Epithelial ovarian cancer is typically diagnosed at an advanced stage. Current state-of-the-art surgery and chemotherapy result in the high incidence of complete remissions; however, the recurrence rate is also high. For most patients, the disease eventually becomes a continuum of symptom-free periods and recurrence episodes. Different targeted treatment approaches and biological drugs, currently under development, bring the promise of turning ovarian cancer into a manageable chronic disease. In this review, we discuss the current standard in the therapy for ovarian cancer, major recent studies on the new variants of conventional therapies, and new therapeutic approaches, recently approved and/or in clinical trials. The latter include anti-angiogenic therapies, polyADP-ribose polymerase (PARP) inhibitors, inhibitors of growth factor signaling, or folate receptor inhibitors, as well as several immunotherapeutic approaches. We also discuss cost-effectiveness of some novel therapies and the issue of better selection of patients for personalized treatment.
8 May 2007 in Proceedings of the National Academy of Sciences
Targeting of the Hsp function in tumor cells is currently being assessed as potential anticancer therapy. An improved understanding of the molecular signals that trigger or attenuate the stress protein response is essential for advances to be made in this field. The present study provides evidence that the membrane fluidizer benzyl alcohol (BA), a documented nondenaturant, acts as a chaperone inducer in B16(F10) melanoma cells. It is demonstrated that this effect relies basically on heat shock transcription factor 1 (HSF1) activation. Under the conditions tested, the BA-induced Hsp response involves the up-regulation of a subset of hsp genes. It is shown that the same level of membrane fluidization (estimated in the core membrane region) attained with the closely analogous phenethyl alcohol (PhA) does not generate a stress protein signal. BA, at a concentration that activates heat shock genes, exerts a profound effect on the melting of raft-like cholesterol-sphingomyelin domains in vitro , whereas PhA, at a concentration equipotent with BA in membrane fluidization, has no such effect. Furthermore, through the in vivo labeling of melanoma cells with a fluorescein labeled probe that inserts into the cholesterol-rich membrane domains [fluorescein ester of polyethylene glycol-derivatized cholesterol (fPEG-Chol)], we found that, similarly to heat stress per se , BA, but not PhA, initiates profound alterations in the plasma membrane microdomain structure. We suggest that, apart from membrane hyperfluidization in the deep hydrophobic region, a distinct reorganization of cholesterol-rich microdomains may also be required for the generation and transmission of stress signals to activate hsp genes.
The introduction of microarray techniques to cancer research brought great expectations for finding biomarkers that would improve patients treatment; however, the results of such studies are poorly reproducible, and critical analyses of these methods are rare. In this study we examined gene expression in 97 ovarian cancer samples. Validation of results by quantitative RT-PCR was performed also on 30 additional ovarian cancer samples. We carried out a number of systematic analyses in relation to several defined clinicopathological features. The main goal of our study was to delineate the molecular background of ovarian cancer chemoresistance and find biomarkers suitable for prediction of patients prognosis. Histological tumor type was the major source of variability in genes expression, except for serous and undifferentiated tumors that showed nearly identical profiles. Analysis of clinical endpoints (tumor response to chemotherapy, overall survival, disease-free survival, DFS) brought results that were not confirmed by validation either on the same group or on the independent group of patients. CLASP1 was the only gene that was found as important for DFS in the independent group, while in the preceding experiments it showed associations with other clinical endpoints and with BRCA1 gene mutation; thus, it may be worth of further testing. Our results confirm that histological tumor type is a strong confounding factor and gene expression studies of ovarian carcinomas should be performed on histologically homogeneous groups. Relatively small and unequal patients groups, may be a reason of poor reproducibility of statistical results, as well as the fact that the patients were treated with different chemotherapies. In addition, clinical endpoints may depend on subtle changes in many alternative molecular pathways, and this may be difficult to demonstrate by the methods applied. Also, arbitrarily performed division of samples may not reflect their true biological diversity
2 December 2015 in Postępy Higieny I Medycyny Doświadczalnej
Ovarian cancer is the most frequent cause of deaths from among gynecologic malignancies. Due to its asymptomatic development the disease is frequently diagnosed at an advanced, incurable stages. Although ovarian cancers usually respond well to the first line chemotherapy based on platinum compounds and taxanes, majority of patients develop recurrence and chemo-resistance. Despite many years of studies there is still lack of reliable diagnostic markers as well as other diagnostic methods enabling early detection and suitable for screening. Thus, current studies are aimed on finding new biomarkers with diagnostic, prognostic and predictive potential as well as on the search for the new therapeutic targets. Interestingly, an understanding of ovarian cancer etiology has changed fundamentally within recent years. The classical theory, claiming that ovarian cancers originate from ovarian surface epithelial cells, was undermined. Currently, there is a lot of evidence that majority of serous ovarian cancers have its origin in malignant tubal epithelium, while endometrioid and clear cell ovarian cancers develop most likely from endometriosis. These new findings will have an impact on diagnostic approaches as well as on the prevention options for women with genetic predisposition to ovarian cancer. The new knowledge about an origin of different histological types of ovarian cancer may open new pathways in basic research and clinical studies. In this paper we report current knowledge about ovarian cancer risk factors, we also present the arguments for extraovarian origin of the majority of ovarian cancers and stress the mechanisms of action of new drugs for targeted therapies that show most promising results in the current clinical trials.
PURPOSE: The study was undertaken to evaluate the frequency of inherited medullary thyroid carcinoma (MTC) among patients with apparent sporadic disease. A stepwise algorithm was used depending on clinical indices and the age of patient at MTC diagnosis. PATIENTS AND METHODS: One hundred sixteen patients with MTC verified by postoperative pathologic examination were subjected to genetic analysis of RET exons 10, 11, 13, 14, and 16 by means of polymerase chain reaction, restriction endonuclease digestion, and DNA sequencing. RESULTS: Among 116 apparent sporadic MTC patients, we identified eleven (9.5%) RET germline mutation carriers. Seven of these (6.0%) were found by routine analysis (exons 10 and 11). The frequency of inherited disease among patients younger than 45 years at diagnosis was 10.2% by analysis of typical mutations in exons 10 and 11. Extended genetic analysis (sequencing of exons 11, 13, 14, and 16) yielded 6.1% additional diagnoses, giving a risk of 16.3% in this age group. One previously unreported mutation in exon 11 affected codon 649 (TCG>TTG, Ser>Leu). In the true sporadic MTC patients younger than 30 years at diagnosis, frequencies of 36% and 4.5% in polymorphic variants L769L and S836S, respectively, were observed. The frequency for L769L was higher than in older patients (P < .05). CONCLUSION: The frequency of inherited disease among apparent sporadic medullary thyroid carcinoma patients is close to 10% in the Polish population of MTC patients. The extended analysis of all known RET proto-oncogene mutation sites is obligatory in patients younger than 45 years at diagnosis, but we also see the need to analyze the impact of rarer mutations in older patients.
Background: During functional studies on the rat stress-inducibleHspa1b(hsp70.1) gene we noticed that some liposome-based DNA carriers, which are used for transfection, induce its promoter activity. This observation concerned commercial liposome formulations (LA), Lipofectin and Lipofectamine 2000. This work was aimed to understand better the mechanism of this phenomenon and its potential biological and practical consequences.Results: We found that a reporter gene driven byHspa1bpromoter is activated both in the case of transient transfections and in the stably transfected cells treated with LA. Using several deletion clones containing different fragments ofHspa1bpromoter, we found that the regulatory elements responsible for most efficient LA-driven inducibility were located between nucleotides -269 and +85, relative to the transcription start site. Further studies showed that the induction mechanism was independent of the classical HSE-HSF interaction that is responsible for gene activation during heat stress. Using DNA microarrays we also detected significant activation of the endogenousHspa1bgene in cells treated with Lipofectamine 2000. Several other stress genes were also induced, along with numerous genes involved in cellular metabolism, cell cycle control and pro-apoptotic pathways.Conclusions: Our observations suggest that i) some cationic liposomes may not be suitable for functional studies onhsppromoters, ii) lipofection may cause unintended changes in global gene expression in the transfected cells.