Andres Klein-Szanto

Publications of Andres Klein-Szanto

• Deletion of p120-catenin results in a tumor microenvironment with inflammation and cancer that establishes it as a tumor suppressor gene.

  Authors: Douglas B Stairs, Lauren J Bayne, Ben Rhoades, Maria E Vega, Todd J Waldron, Jiri Kalabis, Andres Klein-Szanto, Ju-Seog Lee, Jonathan P Katz, J Alan Diehl, Albert B Reynolds, Robert H Vonderheide, Anil K Rustgi

  Cancer cell. 04/2011; 19(4):470-83.

  p120-catenin (p120ctn) interacts with E-cadherin, but to our knowledge, no formal proof that p120ctn functions as a bona fide tumor suppressor gene has emerged to date. We report herein that p120ctnp120-catenin (p120ctn) interacts with E-cadherin, but to our knowledge, no formal proof that p120ctn functions as a bona fide tumor suppressor gene has emerged to date. We report herein that p120ctn loss leads to tumor development in mice. We have generated a conditional knockout model of p120ctn whereby mice develop preneoplastic and neoplastic lesions in the oral cavity, esophagus, and squamous forestomach. Tumor-derived cells secrete granulocyte macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF), monocyte chemotactic protein-1 (MCP-1), and tumor necrosis factor-α (TNFα). The tumors contain significant desmoplasia and immune cell infiltration. Immature myeloid cells comprise a significant percentage of the immune cells present and likely participate in fostering a favorable tumor microenvironment, including the activation of fibroblasts.

• Identification of the Rac-GEF P-Rex1 as an essential mediator of ErbB signaling in breast cancer.

  Authors: Maria Soledad Sosa, Cynthia Lopez-Haber, Chengfeng Yang, Hongbin Wang, Mark A Lemmon, John M Busillo, Jiansong Luo, Jeffrey L Benovic, Andres Klein-Szanto, Hiroshi Yagi, J Silvio Gutkind, Ramon E Parsons, Marcelo G Kazanietz

  Molecular cell. 12/2010; 40(6):877-92.

  While the small GTPase Rac1 and its effectors are well-established mediators of mitogenic and motile signaling by tyrosine kinase receptors and have been implicated in breast tumorigenesis, little isWhile the small GTPase Rac1 and its effectors are well-established mediators of mitogenic and motile signaling by tyrosine kinase receptors and have been implicated in breast tumorigenesis, little is known regarding the exchange factors (Rac-GEFs) that mediate ErbB receptor responses. Here, we identify the PIP(3)-Gβγ-dependent Rac-GEF P-Rex1 as an essential mediator of Rac1 activation, motility, cell growth, and tumorigenesis driven by ErbB receptors in breast cancer cells. Notably, activation of P-Rex1 in breast cancer cells requires the convergence of inputs from ErbB receptors and a Gβγ- and PI3Kγ-dependent pathway. Moreover, we identified the GPCR CXCR4 as a crucial mediator of P-Rex1/Rac1 activation in response to ErbB ligands. P-Rex1 is highly overexpressed in human breast cancers and their derived cell lines, particularly those with high ErbB2 and ER expression. In addition to the prognostic and therapeutic implications, our findings reveal an ErbB effector pathway that is crucial for breast cancer progression.

• Raloxifene-stimulated experimental breast cancer with the paradoxical actions of estrogen to promote or prevent tumor growth: a unifying concept in anti-hormone resistance.

  Authors: Gregor M Balaburski, Rita C Dardes, Michael Johnson, Bassem Haddad, Fang Zhu, Eric A Ross, Surojeet Sengupta, Andres Klein-Szanto, Hong Liu, Eun Sook Lee, Helen Kim, V Craig Jordan

  International journal of oncology. 08/2010; 37(2):387-98.

  We have previously demonstrated that prolonged treatments with raloxifene (RAL) in vitro will result in phase II RAL resistance and RAL-induced tumor growth. Clinical interest prompted us toWe have previously demonstrated that prolonged treatments with raloxifene (RAL) in vitro will result in phase II RAL resistance and RAL-induced tumor growth. Clinical interest prompted us to re-examine RAL resistance in vivo, particularly the effects of long-term treatments (a decade or more) on the evolution of RAL resistance. In this study, we have addressed the question of this being a reproducible phenomenon in wild-type estrogen receptor (ER)-positive human breast cell line MCF-7. MCF-7 cells cultured under estrogen-deprived conditions in the presence of 1 microM RAL for more than a year develop RAL resistance resulting in an independent cell line, MCF7-RAL. The MCF7-RAL cells grow in response to both estradiol E2 and RAL. Fulvestrant (FUL) blocks RAL and E2-mediated growth. Transplantation of MCF7-RAL cells into athymic ovariectomized mice and treatment with physiologic doses of E2 causes early E2-stimulated tumor growth. In contrast, continuous treatment of implanted animals with daily oral RAL (1.5 mg daily) causes growth of small tumors within 15 weeks. Continuous re-transplantation of the tumors growing in RAL-treated mice indicated that RAL stimulated tumor growth. Tumors in the untreated mice did not grow. Bi-transplantation of MCF7-E2 and MCF7-RAL tumors into the opposing mammary fat pads of the same ovariectomized animal demonstrated that MCF7-E2 grew with E2 stimulation and not with RAL. Conversely, MCF7-RAL tumors grew with RAL and not E2, a characteristic of phase II resistance. Established phase II resistance of MCF7-RAL tumors was confirmed following up to 7 years of serial transplantation in RAL-treated athymic mice. The ERalpha was retained in these tumors. The cyclical nature of RAL resistance was confirmed and extended during a 2-year evolution of the resistant phases of the MCF7-RAL tumors. The MCF7-RAL tumors that initially were inhibited by E2 grew in the presence of E2 and subsequently grew with either RAL or E2. RAL remained the major grow stimulus and RAL enhanced E2-stimulated growth. Subsequent transplantation of E2 stimulated tumors and evaluations of the actions of RAL, demonstrated robust E2-stimulated growth that was blocked by RAL. These are the characteristics of the anti-estrogenic actions of RAL on E2-stimulated breast cancer growth with a minor component of phase I RAL resistance. Continuous transplantation of the phase I RAL-stimulated tumors for >8 months causes reversion to phase II resistance. These data and literature reports of the cyclical nature of anti-androgen/androgen responsiveness of prostate cancer growth, illustrate the generality of the evolution of anti-hormonal resistance in sex steroid-sensitive target tissues.

• Esophageal squamous cell dysplasia and delayed differentiation with deletion of krüppel-like factor 4 in murine esophagus.

  Authors: Marie-Pier Tetreault, Yizeng Yang, Jenna Travis, Qian-Chun Yu, Andres Klein-Szanto, John W Tobias, Jonathan P Katz

  Gastroenterology. 03/2010; 139(1):171-81.e9.

  Krüppel-like factor 4 (Klf; previously known a gut-enriched Krüppel-like factor) is a DNA-binding transcriptional regulator highly expressed in skin and gastrointestinal epithelia, specifically inKrüppel-like factor 4 (Klf; previously known a gut-enriched Krüppel-like factor) is a DNA-binding transcriptional regulator highly expressed in skin and gastrointestinal epithelia, specifically in regions of cellular differentiation. Homozygous null mice for Klf4 die shortly after birth from skin defects, precluding their analysis at later stages. The aim of this study was to analyze the function of Klf4 in keratinocyte biology and epithelial homeostasis in the adult by focusing on the squamous lined esophagus. By using the ED-L2 promoter of Epstein-Barr virus to drive Cre, we obtained tissue-specific ablation of Klf4 in the squamous epithelia of the tongue, esophagus, and forestomach. Mice with loss of Klf4 in esophageal epithelia survived to adulthood, bypassing the early lethality. Tissue-specific Klf4 knockout mice had increased basal cell proliferation and a delay in cellular maturation; these mice developed epithelial hypertrophy and subsequent dysplasia by 6 months of age. Moreover, loss of Klf4 in vivo was associated with increased expression of the pro-proliferative Klf5, and Klf4 down-regulated Klf5 both transcriptionally and posttranscriptionally. By using gene expression profiling, we also showed decreased expression of critical late-stage differentiation factors and identified alterations of several genes important in cellular differentiation. Klf4 is essential for squamous epithelial differentiation in vivo and interacts with Klf5 to maintain normal epithelial homeostasis.

• NEDD9 Promotes Oncogenic Signaling in Mammary Tumor Development.

  Authors: Eugene Izumchenko, Mahendra K Singh, Olga V Plotnikova, Nadezhda Tikhmyanova, Joy L Little, Ilya G Serebriiskii, Sachiko Seo, Mineo Kurokawa, Brian L Egleston, Andres Klein-Szanto, Elena N Pugacheva, Richard R Hardy, Marina Wolfson, Denise C Connolly, Erica A Golemis

  Cancer research. 10/2009;

  In the past 3 years, altered expression of the HEF1/CAS-L/NEDD9 scaffolding protein has emerged as contributing to cancer metastasis in multiple cancer types. However, whereas some studies haveIn the past 3 years, altered expression of the HEF1/CAS-L/NEDD9 scaffolding protein has emerged as contributing to cancer metastasis in multiple cancer types. However, whereas some studies have identified elevated NEDD9 expression as prometastatic, other work has suggested a negative role in tumor progression. We here show that the Nedd9-null genetic background significantly limits mammary tumor initiation in the MMTV-polyoma virus middle T genetic model. Action of NEDD9 is tumor cell intrinsic, with immune cell infiltration, stroma, and angiogenesis unaffected. The majority of the late-appearing mammary tumors of MMTV-polyoma virus middle T;Nedd9(-/-) mice are characterized by depressed activation of proteins including AKT, Src, FAK, and extracellular signal-regulated kinase, emphasizing an important role of NEDD9 as a scaffolding protein for these prooncogenic proteins. Analysis of cells derived from primary Nedd9(+/+) and Nedd9(-/-) tumors showed persistently reduced FAK activation, attachment, and migration, consistent with a role for NEDD9 activation of FAK in promoting tumor aggressiveness. This study provides the first in vivo evidence of a role for NEDD9 in breast cancer progression and suggests that NEDD9 expression may provide a biomarker for tumor aggressiveness. [Cancer Res 2009;69(18):7198-206].

• Nipple aspirate fluid and ductoscopy to detect breast cancer.

  Authors: Edward R Sauter, Andres Klein-Szanto, Brenda MacGibbon, Hormoz Ehya

  Diagnostic cytopathology. 09/2009;

  We prospectively performed cytologic assessment and image analysis (IA) on matched nipple aspirate fluid (NAF) and mammary ductoscopy (MD) specimens to determine (1) the accuracy of these methods inWe prospectively performed cytologic assessment and image analysis (IA) on matched nipple aspirate fluid (NAF) and mammary ductoscopy (MD) specimens to determine (1) the accuracy of these methods in cancer detection and (2) whether the two collection methods provide complementary information.NAF and MD specimens were collected from 84 breasts from 75 women (nine bilateral samples) who underwent breast surgery. Cytologic evaluation was performed on all samples. IA was performed on slides with sufficient epithelial cells.Cytologic evaluation proved more accurate in patients without pathologic spontaneous nipple discharge (PND) than those with PND, mainly because of the potential false positive diagnosis in the latter. While the sensitivity of NAF and MD cytology was low (10% and 14%, respectively), both were 100% specific in cancer detection in the non-PND cohort. Combining NAF and MD cytology information improved sensitivity (24%) without sacrificing specificity. Similar to cytology, IA was more accurate in patients without PND having high specificity (100% for aneuploid IA), but relatively low sensitivity (36%). Combining NAF and MD cytology with aneuploid IA improved the sensitivity (45%) while maintaining high specificity (100%). The best predictive model was positive NAF cytology and/or MD cytology combined with IA aneuploidy, which resulted in 55% sensitivity and 100% specificity in breast cancer detection.Cytologic evaluation and IA of NAF and MD specimens are complementary. The presence of atypical cells arising from an intraductal papilloma in ductoscopic specimens is a potential source of false positive diagnosis in patients with nipple discharge. Diagn. Cytopathol. 2009 (c) 2009 Wiley-Liss, Inc.

• Mice Heterozygous for Germ-line Mutations in Methylthioadenosine Phosphorylase (MTAP) Die Prematurely of T-Cell Lymphoma.

  Authors: Yuwaraj Kadariya, Bu Yin, Baiqing Tang, Susan A Shinton, Eoin P Quinlivan, Xiang Hua, Andres Klein-Szanto, Tahseen I Al-Saleem, Craig H Bassing, Richard R Hardy, Warren D Kruger

  Cancer research. 07/2009;

  Large homozygous deletions of 9p21 that inactivate CDKN2A, ARF, and MTAP are common in a wide variety of human cancers. The role for CDKN2A and ARF in tumorigenesis is well established, but whetherLarge homozygous deletions of 9p21 that inactivate CDKN2A, ARF, and MTAP are common in a wide variety of human cancers. The role for CDKN2A and ARF in tumorigenesis is well established, but whether MTAP loss directly affects tumorigenesis is unclear. MTAP encodes the enzyme methylthioadenosine phosphorylase, a key enzyme in the methionine salvage pathway. To determine if loss of MTAP plays a functional role in tumorigenesis, we have created an MTAP-knockout mouse. Mice homozygous for a MTAP null allele (Mtap(lacZ)) have an embryonic lethal phenotype dying around day 8 postconception. Mtap/Mtap(lacZ) heterozygotes are born at Mendelian frequencies and appear indistinguishable from wild-type mice during the first year of life, but they tend to die prematurely with a median survival of 585 days. Autopsies on these animals reveal that they have greatly enlarged spleens, altered thymic histology, and lymphocytic infiltration of their livers, consistent with lymphoma. Immunohistochemical staining and fluorescence-activated cell sorting analysis indicate that these lymphomas are primarily T-cell in origin. Lymphoma-infiltrated tissues tend to have reduced levels of Mtap mRNA and MTAP protein in addition to unaltered levels of methyldeoxycytidine. These studies show that Mtap is a tumor suppressor gene independent of CDKN2A and ARF. [Cancer Res 2009;69(14):5961-9].

• Buthionine sulfoximine sensitizes antihormone-resistant human breast cancer cells to estrogen-induced apoptosis.

  Authors: Joan Lewis-Wambi, Helen Kim, Chris Wambi, Roshani Patel, Jennifer Pyle, Andres Klein-Szanto, V Craig Jordan

  Breast cancer research : BCR. 01/2009; 10(6):R104.

  ABSTRACT: INTRODUCTION: Estrogen deprivation using aromatase inhibitors is one of the standard treatments for postmenopausal women with estrogen receptor (ER)-positive breast cancer, however, one ofABSTRACT: INTRODUCTION: Estrogen deprivation using aromatase inhibitors is one of the standard treatments for postmenopausal women with estrogen receptor (ER)-positive breast cancer, however, one of the consequences of prolonged estrogen suppression is acquired drug resistance. Our laboratory is interested in studying antihormone resistance and has previously reported the development of an estrogen deprived human breast cancer cell line, MCF-7:5C, which undergoes apoptosis in the presence of estradiol. In contrast, we have another estrogen deprived cell line, MCF-7:2A, which appears to have elevated levels of glutathione (GSH) and is resistant to estradiol-induced apoptosis. In the present study, we evaluated whether buthionine sulfoximine (BSO), a potent inhibitor of glutathione (GSH) synthesis, is capable of sensitizing antihormone resistant MCF-7:2A cells to estradiol-induced apoptosis. METHODS: Estrogen deprived MCF-7:2A cells were treated with 1 nM E2, 100 microM BSO, or 1 nM E2 +100 microM BSO combination in vitro, and the effects of these agents on cell growth and apoptosis were evaluated by DNA quantitation assay and annexin V and TUNEL staining. The in vitro results of the MCF-7:2A cell line were further confirmed in vivo in a mouse xenograft model. RESULTS: Exposure of MCF-7:2A cells to 1 nM E2 plus 100 microM BSO combination for 48 to 96 hours produced a 7-fold increase in apoptosis whereas the individual treatments had no significant effect on growth. Induction of apoptosis by the combination treatment of E2 plus BSO was evidenced by changes in Bcl-2 and Bax expression. The combination treatment also markedly increased phosphorylated JNK levels in MCF-7:2A cells and blockade of the JNK pathway attenuated the apoptotic effect of E2 plus BSO. Our in vitro findings corroborated in vivo data from a mouse xenograft model in which daily administration of BSO either as a single agent or in combination with E2 significantly reduced tumor growth of MCF-7:2A cells. CONCLUSIONS: Our data indicates that GSH participates in retarding apoptosis in antihormone-resistant human breast cancer cells and that depletion of this molecule by BSO may be critical in predisposing resistant cells to E2-induced apoptotic cell death. We suggest that these data may form the basis of improving therapeutic strategies for the treatment of antihormone resistant ER-positive breast cancer.

• Mouse models of cystathionine {beta}-synthase deficiency reveal significant threshold effects of hyperhomocysteinemia.

  Authors: Sapna Gupta, Jirko Kühnisch, Aladdin Mustafa, Sarka Lhotak, Alexander Schlachterman, Michael J. Slifker, Andres Klein-Szanto, Katherine A High, Richard C Austin, Warren D Kruger

  The FASEB journal : official publication of the Federation of American Societies for Experimental Biology. 12/2008;

  Untreated cystathionine beta-synthase (CBS) deficiency in humans is characterized by extremely elevated plasma total homocysteine (tHcy>200 microM), with thrombosis as the major cause of morbidity.Untreated cystathionine beta-synthase (CBS) deficiency in humans is characterized by extremely elevated plasma total homocysteine (tHcy>200 microM), with thrombosis as the major cause of morbidity. Treatment with vitamins and diet leads to a dramatic reduction in thrombotic events, even though patients often still have severe elevations in tHcy (>80 microM). To understand the difference between extreme and severe hyperhomocysteinemia, we have examined two mouse models of CBS deficiency: Tg-hCBS Cbs(-/-) mice, with a mean serum tHcy of 169 microM, and Tg-I278T Cbs(-/-) mice, with a mean tHcy of 296 microM. Only Tg-I278T Cbs(-/-) animals exhibited strong biological phenotypes, including facial alopecia, osteoporosis, endoplasmic reticulum (ER) stress in the liver and kidney, and a 20% reduction in mean survival time. Metabolic profiling of serum and liver reveals that Tg-I278T Cbs(-/-) mice have significantly elevated levels of free oxidized homocysteine but not protein-bound homocysteine in serum and elevation of all forms of homocysteine and S-adenosylhomocysteine in the liver compared to Tg-hCBS Cbs(-/-) mice. RNA profiling of livers indicate that Tg-I278T Cbs(-/-) and Tg-hCBS Cbs(-/-) mice have unique gene signatures, with minimal overlap. Our results indicate that there is a clear pathogenic threshold effect for tHcy and bring into question the idea that mild elevations in tHcy are directly pathogenic. Gupta, S., Kühnisch, J., Mustafa, A., Lhotak, S., Schlachterman, A., Slifker, M. J., Klein-Szanto, A., High, K. A., Austin, R. C., Kruger, W. D. Mouse models of cystathionine beta-synthase deficiency reveal significant threshold effects of hyperhomocysteinemia.

• Bortezomib induces apoptosis in esophageal squamous cell carcinoma cells through activation of the p38 mitogen-activated protein kinase pathway.

  Authors: Mercedes Lioni, Kazuhiro Noma, Andrew Snyder, Andres Klein-Szanto, J Alan Diehl, Anil K Rustgi, Meenhard Herlyn, Keiran S M Smalley

  Molecular cancer therapeutics. 10/2008; 7(9):2866-75.

  Esophageal squamous cell carcinoma (ESCC) is an exceptionally drug-resistant tumor with a 5-year survival rate <5%. From an initial drug screen, we identified bortezomib as having robust activity inEsophageal squamous cell carcinoma (ESCC) is an exceptionally drug-resistant tumor with a 5-year survival rate <5%. From an initial drug screen, we identified bortezomib as having robust activity in ESCC lines. Mechanistically, bortezomib induced a G(2)-M-phase cell cycle arrest and p53-independent apoptosis associated with caspase cleavage and Noxa induction. Bortezomib also showed excellent activity in organotypic culture and in vivo models of ESCC. Biochemically, bortezomib treatment activated the p38 and c-Jun NH(2)-termnial kinase stress-activated mitogen-activated protein kinase (MAPK) pathways and induced phospho-H2AX activity. Although H2AX is known to cooperate with c-Jun NH(2)-termnial kinase to induce apoptosis following UV irradiation, knockdown of H2AX did not abrogate bortezomib-induced apoptosis. Instead, blockade of p38 MAPK signaling, using either small interfering RNA or a pharmacologic inhibitor, reversed bortezomib-induced apoptosis and the up-regulation of Noxa. Radiation therapy is known to activate the p38 MAPK pathway and is a mainstay of ESCC treatment strategies. In a final series of studies, we showed that the coadministration of bortezomib with irradiation led to enhanced p38 MAPK activity and a significant reduction in colony formation. We therefore suggest that p38 MAPK pathway activation is an excellent potential therapeutic strategy in ESCC. It is further suggested that bortezomib could be added to existing ESCC therapeutic regimens. [Mol Cancer Ther 2008;7(9):2866-75].

• Cdx1 and c-Myc foster the initiation of transdifferentiation of the normal esophageal squamous epithelium toward Barrett's esophagus.

  Authors: Douglas B Stairs, Hiroshi Nakagawa, Andres Klein-Szanto, Shukriyyah D Mitchell, Debra G Silberg, John W Tobias, John P Lynch, Anil K Rustgi

  PLoS ONE. 02/2008; 3(10):e3534.

  BACKGROUND: Barrett's esophagus is a premalignant condition whereby the normal stratified squamous esophageal epithelium undergoes a transdifferentiation program resulting in a simple columnarBACKGROUND: Barrett's esophagus is a premalignant condition whereby the normal stratified squamous esophageal epithelium undergoes a transdifferentiation program resulting in a simple columnar epithelium reminiscent of the small intestine. These changes are typically associated with the stratified squamous epithelium chronically exposed to acid and bile salts as a result of gastroesophageal reflux disease (GERD). Despite this well-defined epidemiologic association between acid reflux and Barrett's esophagus, the genetic changes that induce this transdifferentiation process in esophageal keratinocytes have remained undefined. METHODOLOGY/PRINCIPAL FINDINGS: To begin to identify the genetic changes responsible for transdifferentiaiton in Barrett's esophagus, we performed a microarray analysis of normal esophageal, Barrett's esophagus and small intestinal biopsy specimens to identify candidate signaling pathways and transcription factors that may be involved. Through this screen we identified the Cdx1 homeodomain transcription factor and the c-myc pathway as possible candidates. Cdx1 and c-myc were then tested for their ability to induce transdifferentiation in immortalized human esophageal keratinocytes using organotypic culturing methods. Analyses of these cultures reveal that c-myc and cdx1 cooperate to induce mucin production and changes in keratin expression that are observed in the epithelium of Barrett's esophagus. CONCLUSIONS/SIGNIFICANCE: These data demonstrate the ability of Cdx1 and c-myc to initiate the earliest stages of transdifferentiation of esophageal keratinocytes toward a cell fate characteristic of Barrett's esophagus.

• Memory CD8+ T cells are gatekeepers of the lymph node draining the site of viral infection.

  Authors: Ren-Huan Xu, Min Fang, Andres Klein-Szanto, Luis J Sigal

  Proceedings of the National Academy of Sciences of the United States of America. 07/2007; 104(26):10992-7.

  It is uncertain how immunity protects against systemic viral diseases. Here, we demonstrate that in the absence of persistent virus, not only antibodies but also recall responses by long-lived memoryIt is uncertain how immunity protects against systemic viral diseases. Here, we demonstrate that in the absence of persistent virus, not only antibodies but also recall responses by long-lived memory CD8(+) T cells prevent mousepox, a disease caused by ectromelia virus, a close relative of the virus of human smallpox. Moreover, we show that to protect, recall CD8(+) T cells directly kill targets in the lymph node draining the primary site of infection thus curbing systemic viral spread. Therefore, our work provides the basis for a model where lymph nodes are not just organs where lymphocytes become activated and proliferate but also the sites where a major fight against virus spread takes place.

• Clinical implications of fibroblast activation protein in patients with colon cancer.

  Authors: Leonard R Henry, Hyung-Ok Lee, John S Lee, Andres Klein-Szanto, Perry Watts, Eric A Ross, Wen-Tien Chen, Jonathan D Cheng

  Clinical cancer research : an official journal of the American Association for Cancer Research. 04/2007; 13(6):1736-41.

  PURPOSE: Human fibroblast activation protein (FAP)/seprase is a 97-kDa surface glycoprotein expressed on tumor associated fibroblasts in the majority of epithelial cancers including colonPURPOSE: Human fibroblast activation protein (FAP)/seprase is a 97-kDa surface glycoprotein expressed on tumor associated fibroblasts in the majority of epithelial cancers including colon adenocarcinomas. FAP overexpression in human tumor cells has been shown to promote tumor growth in animal models, and clinical trials targeting FAP enzymatic activity have been initiated. The primary objective of this study was to evaluate the clinical significance of stromal FAP in human colon cancers by immunohistochemisty. EXPERIMENTAL DESIGN: Sections of paraffin-embedded resected primary human colon cancer specimens from 1996 through 2001 within the Fox Chase Cancer Center tumor bank were stained with D8 antibody directed against FAP/seprase. Xenotransplanted human colorectal tumors in mice were examined similarly for stromal FAP in tumors of different sizes. Overall percentage of stromal FAP staining of the primary tumor was assessed semiquantitatively (0, 1+, 2+, 3+) and staining intensity was also graded (none, weak, intermediate, strong). Survival time and time to recurrence data were analyzed using Kaplan-Meier plots, log-rank tests, and Cox proportional hazards models. RESULTS: One hundred thirty-eight patients with resected specimens were available for study (mean follow-up, 1,050 days) with 6 (4%) stage I, 52 (38%) stage II, 43 (31%) stage III, and 37 (27%) stage IV patients. FAP was detected in >93% of specimens. Semiquantitative staining was scored as 1+ in 28 (20%), 2+ in 52 (38%), and 3+ in 49 (35%). FAP staining intensity was graded as weak in 45 (33%), intermediate in 48 (35%), and dark in 36 (26%). Stromal FAP was found to correlate inversely with tumor stage (semiquantitative, P = 0.01; intensity, P = 0.009) and with tumor size of the tumor xenograft model (correlation coefficient, -0.61; P = 0.047), suggesting that stromal FAP may have a greater role in the early development of tumors. Furthermore, greater stromal FAP for patients with known metastatic disease was associated with a decreased survival. CONCLUSION: Our data indicate that patients whose colon tumors have high levels of stromal FAP are more likely to have aggressive disease progression and potential development of metastases or recurrence. This study affirms the rationale for ongoing clinical investigations using FAP as a therapeutic target to disrupt FAP-driven tumor progression in patients with metastatic disease. It also suggests that the effects of FAP inhibition should be investigated in earlier-stage tumors, given its high levels and potential effect earlier in the course of the disease.

• RAD001 (Everolimus) delays tumor onset and progression in a transgenic mouse model of ovarian cancer.

  Authors: Seiji Mabuchi, Deborah A Altomare, Denise C Connolly, Andres Klein-Szanto, Samuel Litwin, Matthew K Hoelzle, Harvey H Hensley, Thomas C Hamilton, Joseph R Testa

  Cancer research. 04/2007; 67(6):2408-13.

  The mammalian target of rapamycin (mTOR) is thought to play a critical role in regulating cell growth, cell cycle progression, and tumorigenesis. Because the AKT-mTOR pathway is frequentlyThe mammalian target of rapamycin (mTOR) is thought to play a critical role in regulating cell growth, cell cycle progression, and tumorigenesis. Because the AKT-mTOR pathway is frequently hyperactivated in ovarian cancer, we hypothesized that the mTOR inhibitor RAD001 (Everolimus) would inhibit ovarian tumorigenesis in transgenic mice that spontaneously develop ovarian carcinomas. We used TgMISIIR-TAg transgenic mice, which develop bilateral ovarian serous adenocarcinomas accompanied by ascites and peritoneal dissemination. Fifty-eight female TgMISIIR-TAg mice were treated with 5 mg/kg RAD001 or placebo twice weekly from 5 to 20 weeks of age. To monitor tumor development, mice were examined biweekly using magnetic resonance microimaging. In vivo effects of RAD001 on Akt-mTOR signaling, tumor cell proliferation, and blood vessel area were analyzed by immunohistochemistry and Western blot analysis. RAD001 treatment markedly delayed tumor development. Tumor burden was reduced by approximately 84%. In addition, ascites formation, together with peritoneal dissemination, was detected in only 21% of RAD001-treated mice compared with 74% in placebo-treated animals. Approximately 30% of RAD001-treated mice developed early ovarian carcinoma confined within the ovary, whereas all placebo-treated mice developed advanced ovarian carcinoma. Treatment with RAD001 diminished the expression of vascular endothelial growth factor in tumor-derived cell lines and inhibited angiogenesis in vivo. RAD001 also attenuated the expression of matrix metalloproteinase-2 and inhibited the invasiveness of tumor-derived cells. Taken together, these preclinical findings suggest that mTOR inhibition, alone or in combination with other molecularly targeted drugs, could represent a promising chemopreventive strategy in women at high familial risk of ovarian cancer.

• A reduction of cyclooxygenase 2 gene dosage counters the ovarian morphological aging and tumor phenotype in Wv mice.

  Authors: Wan-Lin Yang, Kathy Qi Cai, Jennifer L Smedberg, Elizabeth R Smith, Andres Klein-Szanto, Thomas C Hamilton, Xiang-Xi Xu

  The American journal of pathology. 04/2007; 170(4):1325-36.

  Menopausal ovaries undergo morphological changes, known as ovarian aging, which are implicated in the high incidence of ovarian cancer occurring during the perimenopausal and immediate postmenopausalMenopausal ovaries undergo morphological changes, known as ovarian aging, which are implicated in the high incidence of ovarian cancer occurring during the perimenopausal and immediate postmenopausal periods. The germ cell-deficient Wv mice recapitulate these postmenopausal alterations in ovarian morphology and develop tubular adenomas. We demonstrate that a reduction of cyclooxygenase 2 gene dosage rescued the ovarian aging phenotype of the Wv mice, whereas homozygous deletion was accompanied by a compensatory increase in ovarian cyclooxygenase 1 expression and prostaglandin E(2) synthesis. Cyclooxygenase inhibitors also reduced the tumor phenotype in a preliminary study. These findings suggest that increased cyclooxygenase activity contributes to the preneoplastic morphological changes of the ovarian surface epithelium, which can be reversed by a reduction of gene dosage achieved by either genetic or pharmacological approaches.

• Pten loss in the mouse thyroid causes goiter and follicular adenomas: insights into thyroid function and Cowden disease pathogenesis.

  Authors: Nicole Yeager, Andres Klein-Szanto, Shioko Kimura, Antonio Di Cristofano

  Cancer research. 03/2007; 67(3):959-66.

  Inactivation and silencing of the tumor suppressor PTEN are found in many different epithelial tumors, including thyroid neoplasia. Cowden Disease patients, who harbor germ-line PTEN mutations, oftenInactivation and silencing of the tumor suppressor PTEN are found in many different epithelial tumors, including thyroid neoplasia. Cowden Disease patients, who harbor germ-line PTEN mutations, often display thyroid abnormalities, including multinodular goiter and follicular adenomas, and are at increased risk of thyroid cancer. To gain insights into the role PTEN plays in thyroid function and disease, we have generated a mouse strain, in which Cre-mediated recombination is used to specifically delete Pten in the thyrocytes. We found that Pten mutant mice develop diffuse goiter characterized by extremely enlarged follicles, in the presence of normal thyroid-stimulating hormone and T4 hormone levels. Loss of Pten resulted in a significant increase in the thyrocyte proliferative index, which was more prominent in the female mice, and in increased cell density in the female thyroid glands. Surprisingly, goitrogen treatment did not cause a substantial increase of the mutant thyroid size and increased only to some extent the proliferation index of the female thyrocytes, suggesting that a relevant part of the thyroid-stimulating hormone-induced proliferation signals are funneled through the phosphatidylinositol-3-kinase (PI3K)/Akt cascade. Although complete loss of Pten was not sufficient to cause invasive tumors, over two thirds of the mutant females developed follicular adenomas by 10 months of age, showing that loss of Pten renders the thyroid highly susceptible to neoplastic transformation through mechanisms that include increased thyrocyte proliferation. Our findings show that constitutive activation of the PI3K/Akt cascade is sufficient to stimulate continuous autonomous growth and provide novel clues to the pathogenesis of Cowden Disease and sporadic nontoxic goiter.

• Multidrug resistance protein 4 protects bone marrow, thymus, spleen, and intestine from nucleotide analogue-induced damage.

  Authors: Martin G Belinsky, Ping Guo, Kun Lee, Feng Zhou, Elena Kotova, Alex Grinberg, Heiner Westphal, Irina Shchaveleva, Andres Klein-Szanto, James M Gallo, Gary D Kruh

  Cancer research. 02/2007; 67(1):262-8.

  Nucleoside-based analogues are mainstays in the treatment of cancer, viral infections, and inflammatory diseases. Recent studies showing that the ATP-binding cassette transporter, multidrugNucleoside-based analogues are mainstays in the treatment of cancer, viral infections, and inflammatory diseases. Recent studies showing that the ATP-binding cassette transporter, multidrug resistance protein 4, is able to efflux nucleoside and nucleotide analogues from transfected cells suggests that the pump may affect the efficacy of this class of agents. However, the in vivo pharmacologic functions of the pump are largely unexplored. Here, using Mrp4(-/-) mice as a model system, and the nucleotide analogue, 9'-(2'-phosphonylmethoxyethyl)-adenine (PMEA) as a probe, we investigate the ability of Mrp4 to function in vivo as an endogenous resistance factor. In the absence of alterations in plasma PMEA levels, Mrp4-null mice treated with PMEA exhibit increased lethality associated with marked toxicity in several tissues. Affected tissues include the bone marrow, spleen, thymus, and gastrointestinal tract. In addition, PMEA penetration into the brain is increased in Mrp4(-/-) mice. These findings indicate that Mrp4 is an endogenous resistance factor, and that the pump may be a component of the blood-brain barrier for nucleoside-based analogues. This is the first demonstration that an ATP-binding cassette transporter can affect in vivo tissue sensitivity towards this class of agents.

• Biologic markers of breast cancer in nipple aspirate fluid and nipple discharge are associated with clinical findings.

  Authors: Edward R Sauter, Colette Wagner-Mann, Hormoz Ehya, Andres Klein-Szanto

  Cancer detection and prevention. 01/2007; 31(1):50-8.

  BACKGROUND: The aim of this prospective study was to assess predictive markers in nipple aspirate fluid (NAF) and pathologic nipple discharge (PND) collected prior to excisional breast biopsy, asBACKGROUND: The aim of this prospective study was to assess predictive markers in nipple aspirate fluid (NAF) and pathologic nipple discharge (PND) collected prior to excisional breast biopsy, as well as clinical factors available prior to biopsy, with histopathologic results in women with a radiographically suspicious and/or palpable breast lesion. METHODS: 208 NAF samples from 191 women were evaluated for the following candidate predictive proteins and cellular markers: prostate-specific antigen (PSA), human glandular kallikrein 2 (hK2), basic fibroblast growth factor (bFGF), S phase fraction (SPF), DNA index, and cytology. Clinical factors included whether or not the lesion was palpable, menopausal status, history of pregnancy, history of birth control or hormone replacement use, and PND. RESULTS: Considering all women, bFGF (p=0.005) and SPF (0.031) were associated, and abnormal cytology approached an association (p=0.056) with the presence of breast cancer. Women with PND were less likely to have breast cancer (4 vs. 37%, p<0.001) or palpable lesions (10 vs.43%, p<0.001), were younger, had lower PSA levels (p=0.046), and were more likely to have atypical NAF cytology (p=0.002). Excluding PND, increased age, postmenopause (both p<0.01), high bFGF (p=0.004) and low PSA (p=0.05) were associated with cancer. The best breast cancer predictive model included cytology, bFGF, and age (88% sensitive and 57% specific). When the data were divided by menopausal status, the optimal models to predict breast cancer, which included NAF hK2 or PSA and age, were 100% sensitive and 41% specific in pre- vs. 93% sensitive and 12% specific in postmenopausal women. CONCLUSION: NAF and clinical biomarkers are sensitive predictors of whether a breast contains cancer, and may ultimately help guide treatment. Future studies to determine the optimal combination of predictive markers are warranted.

• Age-dependent morphological alterations of human ovaries from populations with and without BRCA mutations.

  Authors: Kathy Qi Cai, Andres Klein-Szanto, Devarajan Karthik, Mitchell Edelson, Mary B Daly, Robert F Ozols, Henry T Lynch, Andrew K Godwin, Xiang-Xi Xu

  Gynecologic oncology. 12/2006; 103(2):719-28.

  OBJECTIVE: From analysis of pre-cancer ovarian tissues obtained from prophylactic oophorectomies, several studies reported the increased ovarian morphological changes in high-risk ovaries, butOBJECTIVE: From analysis of pre-cancer ovarian tissues obtained from prophylactic oophorectomies, several studies reported the increased ovarian morphological changes in high-risk ovaries, but whether these morphological changes are associated with BRCA1/BRCA2 genotypes or are cancer precursors is controversial. Here, we have investigated a recent collection of ovaries from prophylactic oophorectomies and control ovaries from surgeries due to other non-ovarian-related cancer or non-neoplastic diseases to determine if ovarian morphological changes relate to BRCA1/2 genotypes or reproductive history. METHODS: We assembled a panel of archived ovarian tissues: 52 ovarian tissue blocks were from prophylactic oophorectomies of a high-risk (HR) population; 66 ovaries were from surgeries due to non-ovarian-related diseases, referred to as normal-risk (NR) group. The morphology of ovarian tissues was examined, and morphological changes including papillomatosis, invaginations, inclusion cysts, and epithelial stratification were assessed in a blinded fashion. RESULTS: No statistically significant difference in frequency of these histolopathologic features was found between HR and NR groups. However, inclusion cysts and deep invaginations were found much more commonly in women age 45-54 of either HR or NR groups. CONCLUSIONS: This study suggests that no significant increase in the presence of non-neoplastic ovarian morphological changes is associated with BRCA1/BRCA2 mutations. Rather, the frequency of these histological features, especially inclusion cysts, may associate with age or menopausal status. We propose that ovulatory and perimenopausal gonadotropin stimulation produces ovarian morphological changes, and these histological features may promote the transformation of genetically compromised epithelial cells in the development of ovarian cancer.

• Coordinated functions of E-cadherin and transforming growth factor beta receptor II in vitro and in vivo.

  Authors: Claudia D Andl, Brenton B Fargnoli, Takaomi Okawa, Mark Bowser, Munenori Takaoka, Hiroshi Nakagawa, Andres Klein-Szanto, Xianxin Hua, Meenhard Herlyn, Anil K Rustgi

  Cancer research. 11/2006; 66(20):9878-85.

  In epithelial cells, E-cadherin plays a key role in cell-cell adhesion, and loss of E-cadherin is a hallmark of tumor progression fostering cancer cell invasion and metastasis. To examine E-cadherinIn epithelial cells, E-cadherin plays a key role in cell-cell adhesion, and loss of E-cadherin is a hallmark of tumor progression fostering cancer cell invasion and metastasis. To examine E-cadherin loss in squamous cell cancers, we used primary human esophageal epithelial cells (keratinocytes) as a platform and retrovirally transduced wild-type and dominant-negative forms of E-cadherin into these cells. We found decreased cell adhesion in the cells expressing dominant-negative E-cadherin, thereby resulting in enhanced migration and invasion. To analyze which molecular pathway(s) may modulate these changes, we conducted microarray analysis and found up-regulation of transforming growth factor beta receptor II (TbetaRII) in the wild-type E-cadherin-overexpressing cells, which was confirmed by real-time PCR and Western blot analyses. To investigate the in vivo relevance of this finding, we analyzed tissue microarrays of paired esophageal squamous cell carcinomas and adjacent normal esophagus, and we could show a coordinated loss of E-cadherin and TbetaRII in approximately 80% of tumors. To determine if there may be an E-cadherin-dependent regulation of TbetaRII, we show the physical interaction of E-cadherin with TbetaRII and that this is mediated through the extracellular domains of E-cadherin and TbetaRII, respectively. In addition, TbetaRI is recruited to this complex. When placed in the context of three-dimensional cell culture, which reflects the physiologic microenvironment, TbetaRII-mediated cell signaling is dependent upon intact E-cadherin function. Our results, which suggest that E-cadherin regulates TbetaRII function, have important implications for epithelial carcinogenesis characterized through the frequent occurrence of E-cadherin and TbetaRII loss.