[Show abstract][Hide abstract] ABSTRACT: Neuropilin-1 (NRP-1) has emerged as an important driver of tumor-promoting phenotypes of human malignancies. However, incomplete knowledge exists as to how this single-pass transmembrane receptor mediates pleiotropic tumor-promoting functions. The purpose of this study was to evaluate NRP-1 expression and metastatic properties in 94 endometrial cancer and matching serum specimens and in a lung cancer cell line. We found that NRP-1 expression significantly correlated with increased tumoral expression of vascular endothelial growth factor 2 (VEGFR2) and serum levels of hepatocyte growth factor (HGF) and cell growth-stimulating factor (C-GSF). Tumoral NRP-1 also was positively associated with expression of NEDD9, a pro-metastatic protein. In the highly metastatic lung cancer cell line (H1792), stable LKB1 depletion caused increased migration in vitro and accentuated NRP-1 and NEDD9 expression in vivo. Our findings demonstrate that perturbed expression of these targets correlate with metastatic potential of endometrial and lung tumors, providing clinically-relevant biomarker applications for diagnostic and therapeutic targeting.
[Show abstract][Hide abstract] ABSTRACT: Endometrial hyperplasia (EH) is comprised of a spectrum of changes in the endometrium ranging from a slightly disordered pattern that exaggerates the alterations seen in the late proliferative phase of the menstrual cycle to irregular, hyperchromatic lesions that are similar to endometrioid adenocarcinoma. Generally, EH is caused by continuous exposure of estrogen unopposed by progesterone, polycystic ovary syndrome, tamoxifen or hormone replacement therapy. Since it can progress, or often occur coincidentally with endometrial carcinoma, EH is of clinical importance, and the reversion of hyperplasia to normal endometrium represents the key conservative treatment for prevention of the development of adenocarcinoma. Presently, cyclic progestin or hysterectomy constitutes the major treatment options for EH without atypia or with atypia, respectively. However, clinical trials of hormonal therapies and definitive standard treatments remain to be established for the management of EH. Moreover, therapeutic options for EH patients who wish to preserve fertility are challenging and require nonsurgical management. Therefore, future studies should focus on evaluation of new treatment strategies and novel compounds that could simultaneously target pathways involved in the pathogenesis of estradiol-induced EH. Novel therapeutic agents precisely targeting the inhibition of ER, growth factor receptors, and signal transduction pathways are likely to constitute an optimal approach for treatment of EH.
Preview · Article · Oct 2015 · Journal of Gynecologic Oncology
[Show abstract][Hide abstract] ABSTRACT: Autophagy is a highly regulated catabolic process involving lysosomal degradation of intracellular components, damaged organelles, misfolded proteins, and toxic aggregates, reducing oxidative stress and protecting cells from damage. The process is also induced in response to various conditions, including nutrient deprivation, metabolic stress, hypoxia, anticancer therapeutics, and radiation therapy to adapt cellular conditions for survival. Autophagy can function as a tumor suppressor mechanism in normal cells and dysregulation of this process (ie, monoallelic Beclin-1 deletion) may lead to malignant transformation and carcinogenesis. In tumors, autophagy is thought to promote tumor growth and progression by helping cells to adapt and survive in metabolically-challenged and harsh tumor microenvironments (ie, hypoxia and acidity). Recent in vitro and in vivo studies in preclinical models suggested that modulation of autophagy can be used as a therapeutic modality to enhance the efficacy of conventional therapies, including chemo and radiation therapy. Currently, more than 30 clinical trials are investigating the effects of autophagy inhibition in combination with cytotoxic chemotherapies and targeted agents in various cancers. In this review, we will discuss the role, molecular mechanism, and regulation of autophagy, while targeting this process as a novel therapeutic modality, in various cancers.
Preview · Article · Sep 2015 · Cancer Management and Research
[Show abstract][Hide abstract] ABSTRACT: Purpose:
Brivanib, an oral, multi-targeted tyrosine kinase inhibitor with activity against vascular endothelial growth factor (VEGF) and fibroblast growth factor receptor (FGFR) was investigated as a single agent in a phase II trial to assess the activity and tolerability in recurrent or persistent endometrial cancer (EMC).
Patients and methods:
Eligible patients had persistent or recurrent EMC after receiving one to two prior cytotoxic regimens, measurable disease, and performance status of ≤2. Treatment consisted of brivanib 800 mg orally every day until disease progression or prohibitive toxicity. Primary endpoints were progression-free survival (PFS) at six months and objective tumor response. Expression of multiple angiogenic proteins and FGFR2 mutation status was assessed.
Forty-five patients were enrolled. Forty-three patients were eligible and evaluable. Median age was 64 years. Twenty-four patients (55.8%) received prior radiation. Median number of cycles was two (range 1-24). No GI perforations but one rectal fistula were seen. Nine patients had grade 3 hypertension, with one experiencing grade 4 confusion. Eight patients (18.6%; 90% CI 9.6%-31.7%) had responses (one CR and seven PRs), and 13 patients (30.2%; 90% CI 18.9%-43.9%) were PFS at six months. Median PFS and overall survival (OS) were 3.3 and 10.7 months, respectively. When modeled jointly, VEGF and angiopoietin-2 expression may diametrically predict PFS. Estrogen receptor-α (ER) expression was positively correlated with OS.
Brivanib is reasonably well tolerated and worthy of further investigation based on PFS at six months in recurrent or persistent EMC.
No preview · Article · Jul 2014 · Gynecologic Oncology
[Show abstract][Hide abstract] ABSTRACT: The discovery of retinoic acid receptors arose from research into how vitamins are essential for life. Early studies indicated that Vitamin A was metabolized into an active factor, retinoic acid (RA), which regulates RNA and protein expression in cells. Each step forward in our understanding of retinoic acid in human health was accomplished by the development and application of new technologies. Development cDNA cloning techniques and discovery of nuclear receptors for steroid hormones provided the basis for identification of two classes of retinoic acid receptors, RARs and RXRs, each of which has three isoforms, α, β and ɣ. DNA manipulation and crystallographic studies revealed that the receptors contain discrete functional domains responsible for binding to DNA, ligands and cofactors. Ligand binding was shown to induce conformational changes in the receptors that cause release of corepressors and recruitment of coactivators to create functional complexes that are bound to consensus promoter DNA sequences called retinoic acid response elements (RAREs) and that cause opening of chromatin and transcription of adjacent genes. Homologous recombination technology allowed the development of mice lacking expression of retinoic acid receptors, individually or in various combinations, which demonstrated that the receptors exhibit vital, but redundant, functions in fetal development and in vision, reproduction, and other functions required for maintenance of adult life. More recent advancements in sequencing and proteomic technologies reveal the complexity of retinoic acid receptor involvement in cellular function through regulation of gene expression and kinase activity. Future directions will require systems biology approaches to decipher how these integrated networks affect human stem cells, health, and disease.
No preview · Article · May 2014 · Sub-cellular biochemistry
[Show abstract][Hide abstract] ABSTRACT: Objective
There is a lack of reliable indicators to predict who will benefit most from anti-angiogenic therapy, such as bevacizumab. Recognizing obesity is associated with increased levels of VEGF, the main target of bevacizumab, we sought to assess if adiposity, measured in terms of BMI, subcutaneous fat area (SFA), and visceral fat area (VFA) was prognostic.
Reviewed 46 patients with advanced EOC who received primary treatment with bevacizumab-based chemotherapy (N = 21) or chemotherapy alone (N = 25) for whom complete records, CT prior to the first cycle of chemo, and serum were available. CT was used to measure SFA and VFA by radiologists blinded to outcomes. ELISA was used to measure serum levels of VEGF and angiopoietin-2 in the bevacizumab group.
BMI, SFA, and VFA were dichotomized using the median and categorized as “high” or “low”. In the bevacizumab group median PFS was shorter for patients with high BMI (9.8 vs. 24.7 months, p = 0.03), while in the chemotherapy group median PFS was similar between high and low BMI (17.6 vs. 11.9 months, p = 0.19). In the bevacizumab group patients with a high BMI had higher median levels of VEGF and angiopoietin-2, 371.9 vs. 191.4 pg/ml (p = 0.05) and 45.9 vs. 16.6 pg/ml (p = 0.09) respectively. On multivariate analysis neither BMI, SFA, nor VFA were associated with PFS (p = 0.13, p = 0.86, p = 0.16 respectively) or OS (p = 0.14, p = 0.93, p = 0.28 respectively) in the chemotherapy group. However, in the bevacizumab group BMI was significantly associated with PFS (p = 0.02); accounting for confounders adjusted HR for high vs. low BMI was 5.16 (95% CI 1.31–20.24). Additionally in the bevacizumab group SFA was significantly associated with OS (p = 0.03); accounting for confounders adjusted HR for high vs. low SFA was 3.58 (95% CI 1.12–11.43).
Results provide the first evidence in EOC that patients with high levels of adiposity may not derive benefit from bevacizumab and that measurements of adiposity are likely to be a useful biomarker.
No preview · Article · Apr 2014 · Gynecologic Oncology
[Show abstract][Hide abstract] ABSTRACT: Epidemiological studies suggest an association between elevated insulin levels and endometrial cancer. We studied the effects of insulin on normal endometrial cell proliferation with cytotoxicity assays. Organotypic cultures were used to determine the effects of insulin on the development of malignant histological features and anchorage independent growth. Western Blots were used to analyze the mitogen-activated protein kinases and AKT pathways. We found that insulin exerts direct effects on endometrial cells by increasing proliferation and promoting carcinogenesis. Our results suggest that this occurs through ERK 1/2 and glycogen synthase kinase-3β Ser9 phosphorylation.
No preview · Article · Mar 2014 · Cancer Investigation
[Show abstract][Hide abstract] ABSTRACT: SHetA2 is a small molecule flexible heteroarotinoid (Flex-Het) with promising cancer prevention and therapeutic activity. Extensive preclinical testing documented lack of SHetA2 toxicity at doses 25 to 150 fold above effective doses. Knowledge of the SHetA2 molecular target(s) that mediate(s) the mechanism of SHetA2 action is critical to appropriate design of clinical trials and improved analogs. The aim of this study was to develop a method to identify SHetA2 binding proteins in cancer cells. A known metabolite of SHetA2 that has a hydroxyl group available for attachment was synthesized and conjugated to a linker for attachment to a magnetic microsphere. SHetA2-conjugated magnetic microspheres and unconjugated magnetic microspheres were separately incubated with aliquots of a whole cell protein extract from the A2780 human ovarian cancer cell line. After washing away non-specifically bound proteins with the protein extraction buffer, SHetA2-binding proteins were eluted with an excess of free SHetA2. In two independent experiments, an SDS gel band of about 72 kDa was present at differential levels in wells of eluent from SHetA2-microspheres in comparison to wells of eluent from unconjugated microspheres. Mass spectrometry analysis of the bands (QStar) and straight eluents (Orbitrap) identified mortalin (HSPA9) to be present in the eluent from SHetA2-microspheres and not in eluent from unconjugated microspheres. Co-immunoprecipitation experiments demonstrated that SHetA2 interfered with mortalin binding to p53 and p66 Src homologous-collagen homologue (p66shc) inside cancer cells. Mortalin and SHetA2 conflictingly regulate the same molecules involved in mitochondria-mediated intrinsic apoptosis. The results validate the power of this protocol for revealing drug targets.
Electronic supplementary material
The online version of this article (doi:10.1007/s10637-013-0041-x) contains supplementary material, which is available to authorized users.
Full-text · Article · Nov 2013 · Investigational New Drugs
[Show abstract][Hide abstract] ABSTRACT: The occurrence of intestinal polyps in people at high risk for developing colorectal cancer provides an opportunity to test the efficacy of chemoprevention agents. In this situation of treating otherwise healthy people, the potential for toxicity must be minimal. The small molecule flexible heteroarotinoid (Flex-Het), called SHetA2, has chemoprevention activity in organotypic cultures in vitro and lack of toxicity at doses capable of inhibiting xenograft tumor growth in vivo. The objective of this study was to evaluate SHetA2 chemoprevention activity and toxicity in the APCMin/+ murine model. Oral administration of SHetA2 at 30 and 60 mg/kg five days per week for 12 weeks significantly reduced development of intestinal polyps by 40 to 60% depending on the dose and sex of the treatment group. Immunohistochemical and Western blot analysis of polyps demonstrated reduced levels of cyclin D1 and proliferating cell nuclear antigen (PCNA) in both SHetA2 treatment groups. Western blot analysis also demonstrated SHetA2 induction of E-cadherin, Bax and caspase 3 cleavage along with reduction in Bcl-2, cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF), consistent with SHetA2 regulation of apoptosis, inflammation and angiogenesis. Neither dose caused weight loss nor gross toxicity in APCMin/+ or wild type littermates. Magnetic resonance imaging (MRI) of cardiac function showed no evidence of SHetA2 toxicity. SHetA2 did not alter left ventricular wall thickness. In summary, SHetA2 exerts chemoprevention activity without overt or cardiac toxicity in the APCMin/+ model. SHetA2 modulation of biomarkers in colon polyps identifies potential pharmacodynamic endpoints for SHetA2 clinical trials.
Full-text · Article · Jul 2013 · Cancer Prevention Research
[Show abstract][Hide abstract] ABSTRACT: Objective:
This study aims to assess the role of polymorphisms in DNA repair genes, excision repair cross-complementation group 1 (ERCC1) and methyl-methanesulfonate sensitivity 19 (MMS19), in tumor response to platinum-based chemotherapy and survival in advanced epithelial ovarian cancer (EOC).
Single nucleotide polymorphism (SNP) analysis was performed on the paraffin-embedded tumor tissue of women with advanced EOC, treated with platinum-based chemotherapy at the University of Oklahoma Health Sciences Center. Polymorphisms from two ERCC1 (codon-118 and C8092A) and three MMS19 (rs2211243, rs2236575 and rs872106) gene loci were evaluated by real time PCR Allelic Discrimination Assay.
Genotyping was performed in 107 patients, 45 platinum-sensitive and 62 platinum-resistant. ERCC1, codon-118 and C8092A genotyping was evaluable in 98 and 106 patients respectively and in all 107 patients for MMS19 polymorphisms. No differences were observed in genotype between platinum-sensitive and platinum-resistant patients. Polymorphisms in the ERCC1, codon-118 and MMS19 genes did not correlate with overall survival (OS), although a trend toward improved progression free survival (PFS) was observed in patients expressing the minor (GG) alleles of the rs872106 MMS19 gene. Women homozygous for the ERCC1-C8092A minor (AA) alleles had a significant increase in PFS compared to AC and CC patients and both AA and AC genotypes conferred improved survival over the major (CC) genotype.
Polymorphisms in ERCC1, codon-118 and MMS19 genes are not associated with clinical response to platinum or survival. The ERCC1-C8092A genotypes containing an "A" allele were associated with significant improvement in PFS and OS strengthening the value of this specific genotype in survival.
[Show abstract][Hide abstract] ABSTRACT: A single cell has the potential to kill an entire human being. Efforts to cure cancer are limited by survival of individual cancer cells despite immune surveillance and toxic therapies. Understanding the intricate network of pathways that maintain cellular homeostasis and mediate stress response or default into cell death is critical to the development of strategies to eradicate cancer. Autophagy, proteasomal degradation and the unfolded protein response (UPR) are cellular pathways that degrade and recycle excess or damaged proteins to maintain cellular homeostasis and survival. This review will discuss autophagy and how it is integrated with proteasomal degradation and UPR to govern cell fate through restoration of cellular homeostasis or default into the apoptotic cell death pathway. The first response of autophagy is macroautophagy, which sequesters cytoplasm including organelles inside double-membraned autophagosome vesicles that fuse with lysosomes to degrade and recycle the contents. Ubiquitination patterns on proteins targeted for degradation determine whether adapter proteins will bring them to developing autophagosomes or to proteasomes. Macroautophagy is followed by chaperone-mediated autophagy (CMA), in which Hsc70 (Heat shock cognate 70) selectively binds proteins with exposed KFERQ motifs and pushes them inside lysosomes through the LAMP-2A (Lysosome-associated membrane protein type 2A) receptor. These two processes and the lesser understood microautophagy, which involves direct engulfment of proteins into lysosomes, occur at basal and induced levels. Insufficient proteasome function or ER stress induction of UPR can induce autophagy, which can mitigate damage and stress. If this network is incapable of repairing the damage or overcoming continued stress, the default pathway of apoptosis is engaged to destroy the cell. Induction of macroautophagy by cancer therapeutics has led to clinical trials investigating combinations of HCQ (hydroxychloriquine) suppression of autophagy with apoptosis-inducing agents. Further study of the complex integration of autophagy, proteasomal degradation, UPR and apoptosis is likely to provide additional targets for our fight against cancer. This article is part of a Special Issue entitled "Apoptosis: Four Decades Later".
Full-text · Article · Oct 2012 · Experimental oncology
[Show abstract][Hide abstract] ABSTRACT: SHetA2 is a heteroarotinoid that has shown selective inhibition of cancer cell growth and an induction of apoptosis without activation of nuclear retinoic acid receptors. In the rat study, SHetA2 was administered in 1% aqueous methylcellulose/0.2% Tween 80 by oral gavage at 0, 100, 500, and 2,000 mg/kg/day for 28 days. The high-dose administration induced decreased activity in male rats, decreased body-weight gains and food consumption, and changes in organ weights. The major metabolite of SHetA2 in rat plasma was monohydroxy SHetA2, which was considerably higher than the parent compound after oral and intravenous administration. Pharmacokinetic analysis showed extremely low (<1%) systemic bioavailability of SHetA2 for all doses tested. The dose of 2,000 mg/kg/day was considered as the lowest observed adverse effect level. The no observed adverse effect level (NOAEL) was 500 mg/kg/day. In the dog study, no toxicity of SHetA2 in 30% aqueous Solutol(®) HS 15 was observed in any tested dose groups (0, 100, 400, and 1,500 mg/kg/day). The major metabolite of SHetA2 in dog plasma was also monohydroxy SHetA2, which was equal to or lower than the parent compound after oral administration. SHetA2 levels in dog plasma were notably higher, when compared to levels in rat plasma. However, exposure was not dose proportional, as exemplified by a lack of proportional increase in maximum concentration or area under the plasma concentration-time curve with increasing dose. The NOAEL was not established and was considered to be above 1,500 mg/kg/day.
No preview · Article · Sep 2012 · Drug and Chemical Toxicology