Treatment-related protein biomarker expression differs between primary and recurrent ovarian carcinomas.
ABSTRACT The molecular characteristics of recurrent ovarian cancers following chemotherapy treatment have been poorly characterized. Such knowledge could impact salvage therapy selection. Since 2008, we have profiled 168 patients' ovarian cancers to determine the expression of proteins that may predict chemotherapy response or are targets for drugs that are in clinical trials for ovarian cancer treatment. Expression of epidermal growth factor receptor (EGFR), HER2, VEGF, ER, c-Met, IGF1R, Ki67, COX2, PGP/MDR1, BCRP, MRP1, excision repair complementation group 1 (ERCC1), MGMT, TS, RRM1, TOPO1, TOP2A, and SPARC was measured by immunohistochemical analyses at Clinical Laboratory Improvement Amendments-certified laboratories. Our univariate analysis of 56 primary and 50 recurrent tumors from patients with advanced stage ovarian serous carcinoma revealed that PGP and ERCC1 were significantly upregulated in recurrent lesions (P < 0.05). To determine whether these or any of the other markers were differentially expressed in specimens obtained from the same individual at diagnosis and at recurrence, we analyzed 43 matched tumor specimens from 19 advanced stage ovarian carcinoma patients. We confirmed the expression differences in PGP and ERCC1 that were observed in the cohort analysis but discovered that the expression levels of BCRP, RRM1, and COX2 were also discordant in more than 40% of the matched tumor specimens. These results may have implications both for the use of biomarkers in therapy selection as well as for their discovery and validation. Expression of these and other candidate response biomarkers must be evaluated in much larger studies and, if confirmed, support the need for profiling of recurrent tumor specimens in future clinical trials.
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ABSTRACT: Abstract The aim of this study was to develop the heptapeptide-conjugated active targeting nanoparticles for delivery of doxorubicin and siRNA to epidermal growth factor receptor (EGFR) high-expressed breast cancer cells. The active targeting nanoparticles were prepared by using a synthesized poly(D,L-lactide-co-glycolide)-poly(ethylene glycol) (PLGA-PEG) copolymer conjugated with a heptapeptide. The particle size of peptide-conjugated nanoparticles was less than 200 nm with narrow size distribution and the surface charge was negative. The uptake of peptide-conjugated nanoparticles was more efficient in EGFR high-expressed MDA-MB-468 cells than in EGFR low-expressed HepG2 cells by 3.9 folds due to peptide specific binding to EGF receptor followed by EGF receptor-mediated endocytosis. The nanoparticles were used to deliver doxorubicin and siRNA, and their in vitro release was faster in pH 4.0 (500 U lipase) than in pH 7.4. The IC50 of doxorubicin-loaded peptide-conjugated nanoparticles was lower than that of peptide-free nanoparticles by 2.3 folds in MDA-MB-468 cells. Similarly, the cellular growth inhibition of siRNA/DOTAP-loaded peptide-conjugated nanoparticles was 2.1 folds higher than that of peptide-free nanoparticles. In conclusion, the heptapeptide-conjugated PLGA-PEG nanoparticles provided active targeting potential to EGFR high-expressed MDA-MB-468 breast cancer cells, and a synergistic cytotoxicity effect was achieved by co-delivery of doxorubicin and siRNA/DOTAP-loaded peptide-conjugated nanoparticles.Journal of Drug Targeting 07/2013; · 2.77 Impact Factor
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ABSTRACT: Cisplatin and paclitaxel are standard chemotherapy for metastatic ovarian cancer, but with limited efficacy. Cancer stem/progenitor cells (or tumor-initiating cells, TICs) are hypothesized to be chemoresistant, and the existence of TICs in ovarian cancer has been previously demonstrated. However, the key signals and molecular events regulating the formation and expansion of ovarian tumor-initiating cells (OTICs) remain elusive. Here, we show that c-Kit is not just a marker of OTICs, but also a critical mediator of the phenotype that can be a viable target for the treatment of ovarian cancer. In contrast to non-OICs, c-Kit was overexpressed in OTICs. Moreover, the use of small interfering RNA to inhibit c-Kit expression markedly attenuated the number and size of OTIC subpopulations, inhibited the expression of stem cell markers and decreased the tumorigenic capabilities of OTICs. Imatinib (Gleevec), a clinical drug that blocks c-Kit kinase activity, also demonstrated its inhibition potency on OTICs. In addition, cisplatin/paclitaxel, which killed non-OTICs, with c-Kit knockdown or imatinib revealed that this was critically required for intervening ovarian cancer progression and recurrence in vitro and in xenograft tumors in vivo. Similar results were obtained with OTICs derived from ovarian carcinoma patients. Studies into the mechanisms suggest an important role for the activation of Wnt/β-catenin and ATP-binding cassette G2 downstream of c-Kit. The tumor-promoting microenvironment, such as hypoxia, could promote OTICs via upregulation of c-Kit expression. These results unravel an integral role for c-Kit in ovarian neoplastic processes and shed light on its mechanisms of action.Oncogene advance online publication, 16 July 2012; doi:10.1038/onc.2012.290.Oncogene 07/2012; · 8.56 Impact Factor
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ABSTRACT: Among the gynecological malignancies, ovarian cancer is the leading cause of mortality in developed countries. Treatment of ovarian cancer is based on surgery integrated with chemotherapy. Platinum-based drugs (cisplatin and carboplatin) comprise the core of first-line chemotherapy for patients with advanced ovarian cancer. Platinum-resistant ovarian cancer can be treated with cytotoxic chemotherapeutics such as paclitaxel, topotecan, PEGylated liposomal doxorubicin, or gemcitabine, but many patients eventually relapse on treatment. Targeted therapies based on agents specifically directed to overexpressed receptors, or to selected molecular targets, may be the future of clinical treatment. In this regard, overexpression of folate receptor-α on the surface of almost all epithelial ovarian cancers makes this receptor an excellent "tumor-associated antigen". With appropriate use of spacers/linkers, folate-targeted drugs can be distributed within the body, where they preferentially bind to ovarian cancer cells and are released inside their target cells. Here they can exert their desired cytotoxic function. Based on this strategy, 12 years after it was first described, a folate-targeted vinblastine derivative has now reached Phase III clinical trials in ovarian cancer. This review examines the importance of folate targeting, the state of the art of a vinblastine folate-targeted agent (vintafolide) for treating platinum-resistant ovarian cancer, and its diagnostic companion (etarfolatide) as a prognostic agent. Etarfolatide is a valuable noninvasive diagnostic imaging agent with which to select ovarian cancer patient populations that may benefit from this specific targeted therapy.Pharmacogenomics and Personalized Medicine 01/2014; 7:31-42.