Hector Alvarez

University of Texas MD Anderson Cancer Center, Houston, Texas, United States

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Publications (23)120.1 Total impact

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    ABSTRACT: The development of miRNA-based therapeutics represents a new strategy in cancer treatment. The objectives of this study were to evaluate the differential expression of microRNAs in gallbladder cancer (GBC) and to assess the functional role of miR-1 and miR-145 in GBC cell behavior. A profile of miRNA expression was determined using Dharmacon(TM) microarray technology. Differential expression of five microRNAs was validated by TaqMan reverse transcription quantitative-PCR in a separate cohort of 8 tumors and 3 non-cancerous samples. Then, we explored the functional role of miR-1 and miR-145 in tumor cell behavior by ectopic in vitro expression in the GBC NOZ cell line. Several miRNAs were found to be aberrantly expressed in GBC; most of these showed a significantly decreased expression compared to non-neoplastic tissues (Q value < 0.05). The differential expression of 7 selected miRNAs was confirmed by real time PCR. Pathway enrichment analysis revealed that the most deregulated miRNAs (miR-1, miR-133, miR-143 and miR-145) collectively targeted a number of genes belonging to signaling pathways such as TGF-β, ErbB3, WNT and VEGF, and those regulating cell motility or adhesion. The ectopic expression of miR-1 and miR-145 in NOZ cells significantly inhibited cell viability and colony formation (P < 0.01) and reduced gene expression of VEGF-A and AXL. This study represents the first investigation of the miRNA expression profile in gallbladder cancer, and our findings showed that several miRNAs are deregulated in this neoplasm. In vitro functional assays suggest that miR-1 and miR-145 act as tumor suppressor microRNAs in GBC.
    International journal of clinical and experimental pathology. 01/2014; 7(5):1849-67.
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    ABSTRACT: Gallbladder cancer (GBC) is an aggressive neoplasm associated with late diagnosis, unsatisfactory treatment and poor prognosis. Previous work showed that connective tissue growth factor (CTGF) expression is increased in this malignancy. This matricellular protein plays an important role in various cellular processes and its involvement in the tumorigenesis of several human cancers has been demonstrated. However, the precise function of CTGF expression in cancer cells is yet to be determined. The aim of this study was to evaluate the CTGF expression in gallbladder cancer cell lines, and its effect on cell viability, colony formation and in vitro cell migration. CTGF expression was evaluated in seven GBC cell lines by Western blot assay. Endogenous CTGF expression was downregulated by lentiviral shRNA directed against CTGF mRNA in G-415 cells, and the effects on cell viability, anchorage-independent growth and migration was assessed by comparing them to scrambled vector-transfected cells. Knockdown of CTGF resulted in significant reduction in cell viability, colony formation and anchorage-independent growth (P < 0.05). An increased p27 expression was observed in G-415 cells with loss of CTGF function. Our results suggest that high expression of this protein in gallbladder cancer may confer a growth advantage for neoplastic cells.
    International Journal of Experimental Pathology 04/2013; · 2.04 Impact Factor
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    ABSTRACT: Context.-Advanced gallbladder carcinoma (GBC) is a highly fatal disease with poor prognosis and few therapeutic alternatives. The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that plays a central role in cell growth and homeostasis. Its regulation is frequently altered in various tumors and is an attractive target for cancer therapy; however, its status in GBC remains unclear. Objective.-To characterize immunohistochemical expression and prognostic significance of phospho-mTOR in advanced gallbladder carcinoma. Design.-Phospho-mTOR expression was examined by immunohistochemistry in tissue microarrays containing 128 advanced GBCs and 99 cases of chronic cholecystitis, which were divided into 2 groups according to the presence or absence of metaplasia. To evaluate the association of the level of phospho-mTOR expression with clinical variables and patient survival, the advanced GBCs were classified as having low or high expression. Statistical analysis was performed by using a significance level of P < .05, and Kaplan-Meier curves were constructed for survival analysis. Results.-Immunostaining for phospho-mTOR was positive in 82 of 128 tumors (64.1%) and in 24% of chronic cholecystitis cases (16% nonmetaplasia and 32% with metaplasia) (P < .001). Survival analysis indicated that a high phospho-mTOR immunohistochemical expression was associated with poorer prognosis in patients with advanced GBC (P = .02). Conclusions.-Metaplasia is a common finding in chronic cholecystitis and is considered a precursor lesion of dysplasia. Our results suggest that the activation of mTOR occurs very early during the development of GBC, contributing to the carcinogenesis process. Phospho-mTOR expression is correlated with poor survival, supporting the potential of mTOR for targeted therapy.
    Archives of pathology & laboratory medicine 04/2013; 137(4):552-7. · 2.78 Impact Factor
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    ABSTRACT: Context.- Gallbladder cancer (GBC) is an aggressive neoplasia associated with late diagnosis, unsatisfactory treatment, and poor prognosis. Molecular mechanisms involved in GBC pathogenesis remain poorly understood. Connective tissue growth factor (CTGF) is thought to play a role in the pathologic processes and is overexpressed in several human cancers, including GBC. No information is available about CTGF expression in early stages of gallbladder carcinogenesis. Objective.- To evaluate the expression level of CTGF in benign and malignant lesions of gallbladder and its correlation with clinicopathologic features and GBC prognosis. Design.- Connective tissue growth factor protein was examined by immunohistochemistry on tissue microarrays containing tissue samples of chronic cholecystitis (n = 51), dysplasia (n = 15), and GBC (n = 169). The samples were scored according to intensity of staining as low/absent and high CTGF expressers. Statistical analysis was performed using the χ(2) test or Fisher exact probability test with a significance level of P < .05. Survival analysis was assessed by the Kaplan-Meier method and the log-rank test. Results.- Connective tissue growth factor expression showed a progressive increase from chronic cholecystitis to dysplasia and then to early and advanced carcinoma. Immunohistochemical expression (score ≥2) was significantly higher in advanced tumors, in comparison with chronic cholecystitis (P < .001) and dysplasia (P = .03). High levels of CTGF expression correlated with better survival (P = .04). Conclusions.- Our results suggest a role for CTGF in GBC progression and a positive association with better prognosis. In addition, they underscore the importance of considering the involvement of inflammation on GBC development.
    Archives of pathology & laboratory medicine 02/2013; 137(2):245-250. · 2.78 Impact Factor
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    ABSTRACT: Pancreatic cancer is one of the most lethal of human malignancies, and potent therapeutic options are lacking. Inhibition of cell cycle progression through pharmacological blockade of cyclin-dependent kinases (CDK) has been suggested as a potential treatment option for human cancers with deregulated cell cycle control. Dinaciclib (SCH727965) is a novel small molecule multi-CDK inhibitor with low nanomolar potency against CDK1, CDK2, CDK5 and CDK9 that has shown favorable toxicity and efficacy in preliminary mouse experiments, and has been well tolerated in Phase I clinical trials. In the current study, the therapeutic efficacy of SCH727965 on human pancreatic cancer cells was tested using in vitro and in vivo model systems. Treatment with SCH727965 significantly reduced in vitro cell growth, motility and colony formation in soft agar of MIAPaCa-2 and Pa20C cells. These phenotypic changes were accompanied by marked reduction of phosphorylation of Retinoblastoma (Rb) and reduced activation of RalA. Single agent therapy with SCH727965 (40 mg/kg i.p. twice weekly) for 4 weeks significantly reduced subcutaneous tumor growth in 10/10 (100%) of tested low-passage human pancreatic cancer xenografts. Treatment of low passage pancreatic cancer xenografts with a combination of SCH727965 and gemcitabine was significantly more effective than either agent alone. Gene Set Enrichment Analysis identified overrepresentation of the Notch and Transforming Growth Factor-β (TGF-β) signaling pathways in the xenografts least responsive to SCH727965 treatment. Treatment with the cyclin-dependent kinase inhibitor SCH727965 alone or in combination is a highly promising novel experimental therapeutic strategy against pancreatic cancer.
    Cancer biology & therapy 10/2011; 12(7):598-609. · 3.29 Impact Factor
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    ABSTRACT: [This corrects the article on p. e1001356 in vol. 7.].
    PLoS Genetics 05/2011; 7(5). · 8.52 Impact Factor
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    ABSTRACT: Although a combination of genomic and epigenetic alterations are implicated in the multistep transformation of normal squamous esophageal epithelium to Barrett esophagus, dysplasia, and adenocarcinoma, the combinatorial effect of these changes is unknown. By integrating genome-wide DNA methylation, copy number, and transcriptomic datasets obtained from endoscopic biopsies of neoplastic progression within the same individual, we are uniquely able to define the molecular events associated progression of Barrett esophagus. We find that the previously reported global hypomethylation phenomenon in cancer has its origins at the earliest stages of epithelial carcinogenesis. Promoter hypomethylation synergizes with gene amplification and leads to significant upregulation of a chr4q21 chemokine cluster and other transcripts during Barrett neoplasia. In contrast, gene-specific hypermethylation is observed at a restricted number of loci and, in combination with hemi-allelic deletions, leads to downregulatation of selected transcripts during multistep progression. We also observe that epigenetic regulation during epithelial carcinogenesis is not restricted to traditionally defined "CpG islands," but may also occur through a mechanism of differential methylation outside of these regions. Finally, validation of novel upregulated targets (CXCL1 and 3, GATA6, and DMBT1) in a larger independent panel of samples confirms the utility of integrative analysis in cancer biomarker discovery.
    PLoS Genetics 03/2011; 7(3):e1001356. · 8.52 Impact Factor
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    ABSTRACT: Fatty acid synthase (FAS) is overexpressed in many human cancers and is considered to be a promising target for therapy. To investigate the expression of this candidate target in esophageal cancer, we evaluated expression of FAS protein in 22 cases of esophageal squamous cancer, 79 cases of esophageal adenocarcinoma and 16 cases of Barrett's esophagus with high-grade dysplasia--a lesion thought to represent a pre-invasive precursor to esophageal cancer. Using immunohistochemistry, we found significantly higher levels of FAS expression in 77% of the squamous cancers, 96% of the adenocarcinomas and 94% of the Barrett's lesions with high-grade dysplasia, when compared to levels in normal esophageal epithelium and non-dysplastic Barrett mucosa. To evaluate the potential for inhibiting this enzyme as a treatment of esophageal cancer, we treated mice bearing xenografts of the Colo680N esophageal squamous cell carcinoma cell line using C93, a rationally designed molecule that inhibits FAS activity. In these experiments, C93 significantly inhibited the growth of orthotopic xenograft tumors without causing anorexia and weight loss in the treated animals. We conclude that, similar to several other common types of human cancer, FAS is expressed at very high levels in esophageal cancer and growth of these cancers can be inhibited by pharmacological agents that target this enzyme. Moreover, this high expression of FAS is also seen in high-risk, pre-invasive lesions of the esophagus, leading us to propose considering FAS-inhibitors for purposes of esophageal cancer chemoprevention.
    Cancer biology & therapy 09/2010; 10(6):549-54. · 3.29 Impact Factor
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    ABSTRACT: For decades, hundreds of different human tumor type-specific cell lines have been used in experimental cancer research as models for their respective tumors. The veracity of experimental results for a specific tumor type relies on the correct derivation of the cell line. In a worldwide effort, we verified the authenticity of all available esophageal adenocarcinoma (EAC) cell lines. We proved that the frequently used cell lines SEG-1 and BIC-1 and the SK-GT-5 cell line are in fact cell lines from other tumor types. Experimental results based on these contaminated cell lines have led to ongoing clinical trials recruiting EAC patients, to more than 100 scientific publications, and to at least three National Institutes of Health cancer research grants and 11 US patents, which emphasizes the importance of our findings. Widespread use of contaminated cell lines threatens the development of treatment strategies for EAC.
    CancerSpectrum Knowledge Environment 02/2010; 102(4):271-4. · 14.07 Impact Factor
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    ABSTRACT: MicroRNAs (miRNAs) are 21-24 nucleotide RNA molecules that regulate the translation and stability of target messenger RNAs. Abnormal miRNA expression is a common feature of diverse cancers. Several previous studies have classified miRNA expression in pancreatic ductal adenocarcinoma (PDAC), although no uniform pattern of miRNA dysregulation has emerged. To clarify these previous findings as well as to set the stage for detailed functional analyses, we performed global miRNA expression profiling of 21 human PDAC cell lines, the most extensive panel studied to date. Overall, 39 miRNAs were found to be dysregulated and have at least two-fold or greater differential expression in PDAC cell lines compared to control nontransformed pancreatic ductal cell lines. Several of these miRNAs show comparable dysregulation in first-passage patient derived xenografts. Initial functional analyses demonstrate that enforced expression of miRNAs derived from the miR-200 family and the miR-17-92 cluster, both of which are overexpressed in PDAC cell lines, enhances proliferation. In contrast, inhibition of the miR-200 family, the miR-17-92 cluster, or miR-191 diminishes anchorage independent growth. Consistent with a known role for the miR-200 family in negatively regulating an epithelial-to-mesenchymal transition (EMT), the abundance of these miRNAs correlated positively with E-cadherin expression and negatively with the EMT-associated transcription factor and established miR-200 target ZEB1. Finally, restituted expression of miR-34a, a miRNA whose expression is frequently lost in PDAC cell lines, abrogates growth, demonstrating that the anti-proliferative activity of this miRNA is operative in PDAC. These results, and the widespread availability of PDAC cell lines wherein the aforementioned data were generated, provide a valuable resource for the pancreatic cancer research community and will greatly facilitate functional studies essential for elucidating the consequences of miRNA dysregulation in pancreatic cancer.
    Cancer biology & therapy 11/2009; 8(21):2013-24. · 3.29 Impact Factor
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    ABSTRACT: KIT alterations have been identified in melanoma and treatment with imatinib has met with some success. However, the relationship between KIT and melanoma histology remains uncharacterized, and its role in melanoma pathogenesis unknown. We evaluated 70 melanomas from 70 patients seen at a single institution from 1997 to 2008. Cases were analyzed for KIT protein expression relative to histologic variables: subtype, sun damage, tumor infiltrating lymphocytes, melanoma in situ, vertical growth phase (VGP), location, and hyperpigmentation. Twenty-eight cases demonstrated 3+ membranous staining. Univariate analysis revealed 5 significant variables: sun damage (inverse, P = 0.015), tumor location (trunk>extremities>head and neck, P = 0.005), subtype (epithelioid>spindle, mixed>desmoplastic, P < 0.001), VGP (inverse, P = 0.024), and hyperpigmentation [22/26 (85% hyperpigmented cases) and 6/44 (14% nonhyperpigmented cases), P < 0.001]. Upon multivariate analysis, only hyperpigmentation and VGP remained statistically significant (P = 0.002, P = 0.019). Mutational analyses for KIT exons 9 and 11, and BRAF were performed on cases with 3+ labeling. Two of 27 of cases contained mutations in KIT exon 11, whereas only 1 case contained a V600E BRAF mutation, suggesting that KIT and BRAF mutations may be redundant events. Although KIT mutations were uncommon overall, pigmentation in conjunction with immunohistochemistry and nodular growth phase raised their frequency to 2 (40%) of 5 cases. We expand the context of KIT aberrations to involve areas other than acral and mucosal sites and demonstrate an inverse relationship between KIT abnormalities and sun damage. There is a strong correlation to hyperpigmentation that overrides factors including sun damage, tumor location, and histologic subtype, which may be used to identify cases with KIT aberrations.
    The American Journal of dermatopathology 08/2009; 31(7):619-25. · 1.30 Impact Factor
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    ABSTRACT: Pancreatic cancer is a near uniformly lethal disease and a better understanding of the molecular basis of this malignancy may lead to improved therapeutics. The Axl receptor tyrosine kinase is implicated in cellular transformation and tumor progression, although its role in pancreatic cancer has not been previously documented. Axl labeling was present in 54 of 99 (55%), and was absent in 45 of 99 (45%) cases, respectively. Axl expression in pancreatic cancer was significantly associated with lymph node metastases (p < 0.01), and a shorter median survival (12 versus 18 months, p < 0.01), than in tumors with negative labeling. Stable knockdown of Axl resulted in significant reduction in cell viability (p < 0.001), anchorage independent growth (p = 0.0031), as well as attenuation of migratory (p < 0.001) and invasive properties (p < 0.005), compared to vector-transfected cells. Profound inhibition of p42/p44 MAP kinase and PI-3kinase/Akt effector pathways was observed in MIAPaCa-2 cells with loss of Axl function. The reduction in invasion and migration upon Axl knockdown was mirrored by a decrease in the amounts of activated (GTP-bound) GTPase proteins Rho and Rac, significant downregulation in transcript levels of the epithelial mesenchymal transition (EMT)-associated transcription factors slug, snail and twist, and significant decrease in matrix metalloproteinase MMP-9 mRNA levels. The immunohistochemical expression of Axl protein was assessed in a panel of 99 archival pancreatic cancers. Endogenous Axl expression was stably downregulated by lentiviral short hairpin shRNA directed against AXL mRNA in MIAPaCa-2 cells, and the effects on cell viability, anchorage independent growth, invasion, migration and intracellular effector pathways was assessed, by comparing to lentiviral vector-transfected cells. Expression of Axl tyrosine kinase in pancreatic cancers confers an adverse prognostic influence, and represents a new therapeutic target in this malignancy.
    Cancer biology & therapy 04/2009; 8(7):618-26. · 3.29 Impact Factor
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    ABSTRACT: Cholangiocarcinomas (CCAs) are aggressive cancers, with high mortality and poor survival rates. Only radical surgery offers patients some hope of cure; however, most patients are not surgical candidates because of late diagnosis secondary to relatively poor accuracy of diagnostic means. MicroRNAs (miRs) are involved in every cancer examined, but they have not been evaluated in primary CCA. In this study, miR arrays were performed on five primary CCAs and five normal bile duct specimens (NBDs). Several miRs were dysregulated and miR-21 was overexpressed in CCAs. miR-21 differential expression in these 10 specimens was verified by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). To validate these findings, qRT-PCR for miR-21 was then performed on 18 additional primary CCAs and 12 normal liver specimens. MiR-21 was 95% sensitive and 100% specific in distinguishing between CCA and normal tissues, with an area under the receiver operating characteristic curve of 0.995. Inhibitors of miR-21 increased protein levels of programmed cell death 4 (PDCD4) and tissue inhibitor of metalloproteinases 3 (TIMP3). Notably, messenger RNA levels of TIMP3 were significantly lower in CCAs than in normals. Conclusions: MiR-21 is overexpressed in human CCAs. Furthermore, miR-21 may be oncogenic, at least in part, by inhibiting PDCD4 and TIMP3. Finally, these data suggest that TIMP3 is a candidate tumor suppressor gene in the biliary tree.
    Hepatology 03/2009; 49(5):1595-601. · 12.00 Impact Factor
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    ABSTRACT: Esophageal adenocarcinoma currently has one of the most rapidly increasing tumor incidences in the United States, with the vast majority of cases occurring on the backdrop of metaplastic epithelium (Barrett esophagus). The availability of appropriate cell line models is essential for maintaining the pace of esophageal cancer research and for pre-clinical validation of new therapeutic modalities. The identity of several of the widely utilized esophageal adenocarcinoma cell lines (BIC-1, SEG-1 and TE-7) have recently been called into question. Here we describe the establishment and characterization of a bona fide esophageal cancer cell line, JH-EsoAd1, from a patient with Barrett-associated adenocarcinoma. The rapid dissemination of this cancer cell line to the esophageal cancer research community should help ameliorate the current scarcity of preclinical models in this disease.
    Cancer biology & therapy 12/2008; 7(11):1753-5. · 3.29 Impact Factor
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    ABSTRACT: Nanotechnology has enabled significant advances in the areas of cancer diagnosis and therapy. The field of drug delivery is a sterling example, with nanoparticles being increasingly used for generating therapeutic formulations of poorly water-soluble, yet potent anticancer drugs. Whereas a number of nanoparticle-drug combinations are at various stages of preclinical or clinical assessment, the overwhelming majorities of such systems are injectable formulations and are incapable of being partaken orally. The development of an oral nano-delivery system would have distinct advantages for cancer chemotherapy. We report the synthesis and physicochemical characterization of orally bioavailable polymeric nanoparticles composed of N-isopropylacrylamide, methylmethacrylate, and acrylic acid in the molar ratios of 60:20:20 (designated NMA622). Amphiphilic NMA622 nanoparticles show a size distribution of <100 nm (mean diameter of 80 +/- 34 nm) with low polydispersity and can readily encapsulate a number of poorly water-soluble drugs such as rapamycin within the hydrophobic core. No apparent systemic toxicities are observed in mice receiving as much as 500 mg/kg of the orally administered void NMA622 for 4 weeks. Using NMA622-encapsulated rapamycin ("nanorapamycin") as a prototype for oral nano-drug delivery, we show favorable in vivo pharmacokinetics and therapeutic efficacy in a xenograft model of human pancreatic cancer. Oral nanorapamycin leads to robust inhibition of the mammalian target of rapamycin pathway in pancreatic cancer xenografts, which is accompanied by significant growth inhibition (P < 0.01) compared with control tumors. These data indicate that NMA622 nanoparticles provide a suitable platform for oral delivery of water-insoluble drugs like rapamycin for cancer therapy.
    Molecular Cancer Therapeutics 12/2008; 7(12):3878-88. · 5.60 Impact Factor
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    ABSTRACT: Pancreatic cancer is an almost uniformly fatal disease, and early detection is a critical determinant of improved survival. A variety of noninvasive precursor lesions of pancreatic adenocarcinoma have been identified, which provide a unique opportunity for intervention prior to onset of invasive cancer. Biomarker discovery in precursor lesions has been hampered by the ready availability of fresh specimens, and limited yields of proteins suitable for large scale screening. We utilized Liquid Tissue, a novel technique for protein extraction from archival formalin-fixed material, and mass spectrometry to conduct a global proteomic analysis of an intraductal papillary mucinous neoplasm (IPMN). Tissue microarrays comprised of 38 IPMNs were used for validation of candidate proteins. The proteomic analysis of the IPMN Liquid Tissue lysate resulted in identification of 1,534 peptides corresponding to 523 unique proteins. A subset of 25 proteins was identified that had previously been reported as upregulated in pancreatic cancer. Immunohistochemical analysis for two of these, deleted in malignant brain tumors 1 (DMBT1) and tissue transglutaminase 2 (TGM2), confirmed their overexpression in IPMNs. Global proteomics analysis using the Liquid Tissue workflow is a feasible approach for unbiased biomarker discovery in limited archival material, particularly applicable to precursor lesions of cancer.
    Pancreatology 11/2008; 8(6):608-16. · 2.04 Impact Factor
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    ABSTRACT: Recent evidence suggests that blockade of aberrant Hedgehog signaling can be exploited as a therapeutic strategy for pancreatic cancer. Our previous studies using the prototype Hedgehog small-molecule antagonist cyclopamine had shown the striking inhibition of systemic metastases on Hedgehog blockade in spontaneously metastatic orthotopic xenograft models. Cyclopamine is a natural compound with suboptimal pharmacokinetics, which impedes clinical translation. In the present study, a novel, orally bioavailable small-molecule Hedgehog inhibitor, IPI-269609, was tested using in vitro and in vivo model systems. In vitro treatment of pancreatic cancer cell lines with IPI-269609 resembled effects observed using cyclopamine (i.e., Gli-responsive reporter knockdown, down-regulation of the Hedgehog target genes Gli1 and Ptch, as well as abrogation of cell migration and colony formation in soft agar). Single-agent IPI-269609 profoundly inhibited systemic metastases in orthotopic xenografts established from human pancreatic cancer cell lines, although Hedgehog blockade had minimal effect on primary tumor volume. The only discernible phenotype observed within the treated primary tumor was a significant reduction in the population of aldehyde dehydrogenase-bright cells, which we have previously identified as a clonogenic tumor-initiating population in pancreatic cancer. Selective ex vivo depletion of aldehyde dehydrogenase-bright cells with IPI-269609 was accompanied by significant reduction in tumor engraftment rates in athymic mice. Pharmacologic blockade of aberrant Hedgehog signaling might prove to be an effective therapeutic strategy for inhibition of systemic metastases in pancreatic cancer, likely through targeting subsets of cancer cells with tumor-initiating ("cancer stem cell") properties.
    Molecular Cancer Therapeutics 10/2008; 7(9):2725-35. · 5.60 Impact Factor
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    ABSTRACT: Esophageal adenocarcinoma arises in the backdrop of Barrett metaplasia-dysplasia sequence, with the vast majority of patients presenting with late-stage malignancy. Mesothelin, a glycophosphatidylinositol-anchored protein, is aberrantly overexpressed on the surface of many solid cancers. Mesothelin expression was assessed in esophageal tissue microarrays encompassing the entire histological spectrum of Barrett-associated dysplasia and adenocarcinoma. Mesothelin expression was observed in 24/84 (29%) of invasive adenocarcinomas and in 5/34 (15%) lymph node metastases. In contrast, normal squamous and cardiac mucosa, as well as noninvasive Barrett lesions, failed to label with mesothelin. Mesothelin was expressed in the esophageal adenocarcinoma cell line JH-EsoAd1 but not in primary human esophageal epithelial cells. Anti-mesothelin antibody-conjugated CdSe/CDS/ZnS quantum rods were synthesized, and confocal bioimaging confirmed robust binding to JH-EsoAd1 cells. Anti-mesothelin antibody-conjugated nanoparticles can be useful for the diagnosis and therapy of mesothelin-overexpressing esophageal adenocarcinomas.
    Nanomedicine: nanotechnology, biology, and medicine 09/2008; 4(4):295-301. · 6.93 Impact Factor
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    ABSTRACT: Gallbladder carcinoma (GBC) is a highly malignant neoplasm and represents the leading cause of cancer death in Chilean women. In order to determine the potential role of promoter methylation in gallbladder carcinogenesis, we investigated the frequency of this epigenetic mechanism by methylation-specific polymerase chain reaction (MSP) in 35 chronic cholecystitis (CC, separated according to the presence or absence of metaplasia), 19 early cancers (mucosa or muscularis propia invasion) and 48 advanced carcinomas with invasion of the gallbladder subserosa (25 cases) and serosa (23 cases). We examined 14 genes and observed an increase of multigenic methylation during tumoral progression which was not significantly associated with the patient's age. Four genes (DAPK1, DLC1, TIMP3, and RARbeta2) displayed a progressive increase in their methylation status from CC without metaplasia to advanced carcinoma invading the serosa layer (P <or= 0.05). The survival analysis indicated that a methylated condition of DLC1 gene is significantly associated with poor prognosis (P = 0.04), whereas a methylated state of MGMT gene correlated with better patient survival (P = 0.006). Our findings indicate that aberrant hypermethylation of promoter regions is an early, progressive and cumulative event in gallbladder carcinogenesis. Furthermore, the methylation levels seems to accumulate in the progression of CC without metaplasia to CC with metaplasia, a fact that could provide new evidence to consider this morphological adaptation of GB mucosa as a premalignant lesion. Finally, the methylation status of some individual genes could be useful biomarkers with potential clinical application in diagnosis or prognosis of GBC if they are validated in a greater number of clinical samples.
    Molecular Carcinogenesis 06/2008; 48(1):79-89. · 4.27 Impact Factor
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    ABSTRACT: Pancreatic cancer is among the most dismal of human malignancies. Current therapeutic strategies are virtually ineffective in controlling advanced, metastatic disease. Recent evidence suggests that the Hedgehog signalling pathway is aberrantly reactivated in the majority of pancreatic cancers, and that Hedgehog blockade has the potential to prevent disease progression and metastatic spread. Here it is shown that the Hedgehog pathway is activated in the Pdx1-Cre;LsL-Kras(G12D);Ink4a/Arf(lox/lox) transgenic mouse model of pancreatic cancer. The effect of Hedgehog pathway inhibition on survival was determined by continuous application of the small molecule cyclopamine, a smoothened antagonist. Microarray analysis was performed on non-malignant human pancreatic ductal cells overexpressing Gli1 in order to screen for downstream Hedgehog target genes likely to be involved in pancreatic cancer progression. Hedgehog inhibition with cyclopamine significantly prolonged median survival in the transgenic mouse model used here (67 vs 61 days; p = 0.026). In vitro data indicated that Hedgehog activation might at least in part be ascribed to oncogenic Kras signalling. Microarray analysis identified 26 potential Hedgehog target genes that had previously been found to be overexpressed in pancreatic cancer. Five of them, BIRC3, COL11A1, NNMT, PLAU and TGM2, had been described as upregulated in more than one global gene expression analysis before. This study provides another line of evidence that Hedgehog signalling is a valid target for the development of novel therapeutics for pancreatic cancer that might be worth evaluating soon in a clinical setting.
    Gut 06/2008; 57(10):1420-30. · 10.73 Impact Factor

Publication Stats

784 Citations
120.10 Total Impact Points

Institutions

  • 2014
    • University of Texas MD Anderson Cancer Center
      Houston, Texas, United States
  • 2007–2011
    • Johns Hopkins University
      • • Department of Medicine
      • • Department of Pathology
      Baltimore, MD, United States
  • 2008
    • Pontifical Catholic University of Chile
      CiudadSantiago, Santiago, Chile