Reduced expression of BAX is associated with poor prognosis in patients with epithelial ovarian cancer: a multifactorial analysis of TP53, p21, BAX and BCL-2

Unlocking the diagnostic, prognostic roles, and immune implications of BAX gene expression in pan-cancer analysis

OBJECTIVES

Cancer, a formidable disease, continues to challenge our understanding and therapeutic approaches. This study delves into the pan-cancer analysis of BCL2 Associated X (BAX) gene expression, seeking to unravel its significance in cancer development, prognosis, and potential therapeutic strategies.

METHODS

A combination of bioinformatics and molecular experiments.

RESULTS

Our pan-cancer investigation into BAX expression encompassed 33 distinct cancer types, revealing a remarkable and uniform increase in BAX expression. This groundbreaking finding emphasizes the potential universality of BAX's role in cancer development and progression. Further, our study explored the prognostic implications of BAX expression, highlighting a consistent association between up-regulated BAX and poor overall survival (OS) in Liver Hepatocellular Carcinoma (LIHC) and Skin Cutaneous Melanoma (SKCM). These results suggest that BAX may serve as an adverse prognostic indicator in these malignancies, emphasizing the importance of personalized treatment strategies. Epigenetic and genetic analyses of BAX provided valuable insights. Hypomethylation of the BAX promoter region was evident in LIHC and SKCM, which likely contributes to the up-regulation of BAX, while genetic mutations in the BAX gene itself were infrequent in these cancers. Our exploration of BAX-associated signaling pathways and the correlation between BAX expression and CD8+ T cell infiltration shed light on the intricate molecular landscape of cancer. BAX's interaction with key apoptotic and immune-related pathways reinforces its role as a central player in tumor development and the immune microenvironment. Moreover, our drug prediction analysis identified potential therapeutic agents for modulating BAX expression in the context of LIHC and SKCM, bridging the gap between research and clinical application.

CONCLUSION

In sum, our comprehensive BAX study not only enhances our understanding of its significance as a biomarker gene but also offers novel avenues for therapeutic interventions, contributing to the ongoing quest for more effective cancer treatments and improved patient care.

Overcoming Chemotherapy Resistance in Metastatic Cancer: A Comprehensive Review

The management of metastatic cancer is complicated by chemotherapy resistance. This manuscript provides a comprehensive academic review of strategies to overcome chemotherapy resistance in metastatic cancer. The manuscript presents background information on chemotherapy resistance in metastatic cancer cells, highlighting its clinical significance and the current challenges associated with using chemotherapy to treat metastatic cancer. The manuscript delves into the molecular mechanisms underlying chemotherapy resistance in subsequent sections. It discusses the genetic alterations, mutations, and epigenetic modifications that contribute to the development of resistance. Additionally, the role of altered drug metabolism and efflux mechanisms, as well as the activation of survival pathways and evasion of cell death, are explored in detail. The strategies to overcome chemotherapy resistance are thoroughly examined, covering various approaches that have shown promise. These include combination therapy approaches, targeted therapies, immunotherapeutic strategies, and the repurposing of existing drugs. Each strategy is discussed in terms of its rationale and potential effectiveness. Strategies for early detection and monitoring of chemotherapy drug resistance, rational drug design vis-a-vis personalized medicine approaches, the role of predictive biomarkers in guiding treatment decisions, and the importance of lifestyle modifications and supportive therapies in improving treatment outcomes are discussed. Lastly, the manuscript outlines the clinical implications of the discussed strategies. It provides insights into ongoing clinical trials and emerging therapies that address chemotherapy resistance in metastatic cancer cells. The manuscript also explores the challenges and opportunities in translating laboratory findings into clinical practice and identifies potential future directions and novel therapeutic avenues. This comprehensive review provides a detailed analysis of strategies to overcome chemotherapy resistance in metastatic cancer. It emphasizes the importance of understanding the molecular mechanisms underlying resistance and presents a range of approaches for addressing this critical issue in treating metastatic cancer.

Box-Behnken design of thermo-responsive nano-liposomes loaded with a platinum(iv) anticancer complex: evaluation of cytotoxicity and apoptotic pathways in triple negative breast cancer cells

Herein, thermo-responsive liposomes (TLs) loaded with Asp (Asp/TLs) were produced by self-assembling DPPC, DSPE-PEG2000, and cholesterol. The preparation variables were optimized using the Box-Behnken design (BBD). The optimized Asp/TLs exhibited an average particle size of 114.05 ± 1.56 nm, PDI of 0.15 ± 0.015, zeta potential of -15.24 ± 0.65 mV, and entrapment efficiency (EE%) of 84.08 ± 2.75%. In addition, under physiological conditions, Asp/TLs showed spherical shape, outstanding stability and thermo-triggered the release of Asp at 38 °C, reaching the maximum Asp release at 40 °C. The MTT assay showed that the optimal Asp/TLs exhibited the highest cytotoxic activity upon exposure to mild hyperthermia (40 °C) against the invasive triple-negative breast cancer cell line (MDA-MB-231) when compared to other preparations. The IC50 of Asp/TLs (40 °C) was estimated at 0.9 μg mL-1, while that of free Asp (40 °C) was 3.83 μg mL-1. As such, the optimal Asp/TLs were shown to increase the cytotoxic activity of Asp by 4-fold upon exposure to mild hyperthermia. The IC50 values of Asp and Asp/TLs without exposure to 40 °C were 6.6 μg mL-1 and 186 μg mL-1, respectively. This indicated that Asp was released only when placed at 40 °C. The apoptosis assay revealed that Asp/TLs (40 °C) caused a remarkable increase in the percentage of cell population among both the late apoptosis and necrosis quartiles, as well as a significant decline in the viable cell quartile (P ≤ 0.001) when compared to Asp (40 °C). Asp/TLs (40 °C) and Asp (40 °C) could stimulate the intrinsic apoptosis pathway by upregulating the apoptotic genes Bak and Bax, while downregulating the anti-apoptotic genes, BCL-xL and BCL-2. The free Asp (40 °C) increased the gene expression of Bak and Bax by 4.4- and 5.2-folds, while reducing the expression of BCL-xL and BCL-2 by 50% and 73%, respectively. The optimal Asp TLs (40 °C) manifested more potent effects as demonstrated by the upregulation of Bak, Bax, and P53 by 5.6-, 7.2-, and 1.3-folds, as well as the downregulation of BCL-xL and BCL-2 by 70% and 85%, respectively. As such, the optimal Asp TLs (40 °C) treatment displayed the most potent cytotoxic profile and induced both apoptosis and necrosis in MDA-MB-231.

Fabricating niosomal-PEG nanoparticles co-loaded with metformin and silibinin for effective treatment of human lung cancer cells

Background

Despite current therapies, lung cancer remains a global issue and requires the creation of novel treatment methods. Recent research has shown that biguanides such as metformin (MET) and silibinin (SIL) have a potential anticancer effect. As a consequence, the effectiveness of MET and SIL in combination against lung cancer cells was investigated in this study to develop an effective and novel treatment method.

Methods

Niosomal nanoparticles were synthesized via the thin-film hydration method, and field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR), atomic force microscopy (AFM), and dynamic light scattering (DLS) techniques were used to evaluate their physico-chemical characteristics. The cytotoxic effects of free and drug-loaded nanoparticles (NPs), as well as their combination, on A549 cells were assessed using the MTT assay. An apoptosis test was used while under the influence of medication to identify the molecular mechanisms behind programmed cell death. With the use of a cell cycle test, it was determined whether pharmaceutical effects caused the cell cycle to stop progressing. Additionally, the qRT-PCR technique was used to evaluate the levels of hTERT, BAX, and BCL-2 gene expression after 48-h medication treatment.

Results

In the cytotoxicity assay, the growth of A549 lung cancer cells was inhibited by both MET and SIL. Compared to the individual therapies, the combination of MET and SIL dramatically and synergistically decreased the IC50 values of MET and SIL in lung cancer cells. Furthermore, the combination of MET and SIL produced lower IC50 values and a better anti-proliferative effect on A549 lung cancer cells. Real-time PCR results showed that the expression levels of hTERT and BCL-2 were significantly reduced in lung cancer cell lines treated with MET and SIL compared to single treatments (p< 0.001).

Conclusion

It is anticipated that the use of nano-niosomal-formed MET and SIL would improve lung cancer treatment outcomes and improve the therapeutic efficiency of lung cancer cells.

Intrinsic and extrinsic pathways of apoptosis: Role in cancer development and prognosis

Apoptosis, also named programmed cell death, is a fundament process required for morphogenetic homeostasis during early development and in pathophysiological conditions. It is come into existence in 1972 by work of Kerr, Wyllie and Currie and later on investigated during the research on development of the C. elegans. Trigger by several stimuli, apoptosis is necessary during the embryonic development and aging as homeostatic mechanism to control the cell population and also play a key role as defense mechanism against the immune responses and elimination of damaged cells. Cancer, a genetic disease, is a growing burden on the health and economy of both developing and developed countries. Every year there is tremendously increasing in the number of new cancer cases and mortality rate. Although, there is a significant improvement have been made in biotechnological and bioinformatic fields however, the therapeutic advantages and cancer etiology is still under explored. Several studies determined the deregulation of different apoptotic components during the cancer development and progression. Apoptosis relies on activation of distinct signaling pathways that are often deregulated in cancer. Thus, exploring the single or more than one apoptotic component underlying their expression in carcinogenesis could help to track the disease progression. Current book chapter will provide the several evidences supporting the use of different apoptotic components as prognosis and prediction markers in various human cancer types.

A theoretical study on cyclometalated iridium (III) complexes by using a density functional theory

Cyclometalated iridium (III) complexes (Ir1–Ir4) are calculated in detail with computational chemistry methods. The calculated structural parameters of Ir3 are compared with experimental values and a good fit is obtained. IR spectra are calculated at B3LYP/LANL2DZ/6-31G(d) level in the gases phase. Calculated 1H-NMR chemical shift values of the mentioned complexes are compared with the experimental data and all chemical shifts are assigned to the respective atoms. The quantum chemical parameters such as absolute hardness ([Formula: see text]), absolute softness ([Formula: see text]) electronegativity ([Formula: see text]), chemical potential ([Formula: see text]) and electronic charges ([Formula: see text]) are calculated and are associated with the experimental anti-cancer properties of the related complexes. Nonlinear optic properties of the Ir1–Ir4 were investigated with the average linear polarizability ([Formula: see text]), the anisotropy of the polarizability ([Formula: see text]), first hyperpolarizability ([Formula: see text]) values. Hole transfer ([Formula: see text]), electron transfer integrals ([Formula: see text]), hole reorganization energies ([Formula: see text]) and electron reorganization energies ([Formula: see text]) are examined. In addition, molecular docking study was performed. It was found that the molecular docking results are similar to the experimental anti-cancer trend.

EGFR Blockade Reverses Cisplatin Resistance in Human Epithelial Ovarian Cancer Cells

Background:

EOC is one of the most lethal gynecological malignancy worldwide. Although the majority of EOC patients achieve clinical remission after induction therapy, over 80% relapse and succumb to the chemoresistant disease. Previous investigations have demonstrated the association of EGFR with resistance to cytotoxic chemotherapies, hormone therapy, and radiotherapy in the cancers. These studies have highlighted the role of EGFR as an attractive therapeutic target in cisplatin-resistant EOC cells.

Methods:

The human ovarian cell lines (SKOV3 and OVCAR3) were cultured according to ATCC recommendations. The MTT assay was used to determine the chemosensitivity of the cell lines in exposure to cisplatin and erlotinib. The qRT-PCR was applied to analyze the mRNA expression of the desired genes.

Results:

Erlotinib in combination with cisplatin reduced the cell proliferation in the chemoresistant EOC cells in comparison to monotherapy of the drugs (p < 0.05). Moreover, erlotinib/cisplatin combination synergistically decreased the expression of anti-apoptotic and also increased pro-apoptotic genes expression (p < 0.05). Cisplatin alone could increase the expression of MDR genes. The data suggested that EGFR and cisplatin drive chemoresistance in the EOC cells through MEKK signal transduction as well as through EGFR/MEKK pathways in the cells, respectively.

Conclusion:

Our findings propose that EGFR is an attractive therapeutic target in chemoresistant EOC to be exploited in translational oncology, and erlotinib/cisplatin combination treatment is a potential anti-cancer approach to overcome chemoresistance and inhibit the proliferation of the EOC cells.

Targeting Mitochondrial Apoptosis to Overcome Treatment Resistance in Cancer

Deregulated cellular apoptosis is a hallmark of cancer and chemotherapy resistance. The B-cell lymphoma 2 (BCL-2) protein family members are sentinel molecules that regulate the mitochondrial apoptosis machinery and arbitrate cell fate through a delicate balance between pro- and anti-apoptotic factors. The recognition of the anti-apoptotic BCL2 gene as an oncogenic driver in hematological malignancies has directed attention toward unraveling the biological significance of each of the BCL-2 superfamily members in cancer progression and garnered interest in the targeting of apoptosis in cancer therapy. Accordingly, the approval of venetoclax (ABT-199), a small molecule BCL-2 inhibitor, in patients with chronic lymphocytic leukemia and acute myeloid leukemia has become the proverbial torchbearer for novel candidate drug approaches selectively targeting the BCL-2 superfamily. Despite the inspiring advances in this field, much remains to be learned regarding the optimal therapeutic context for BCL-2 targeting. Functional assays, such as through BH3 profiling, may facilitate prediction of treatment response, development of drug resistance and shed light on rational combinations of BCL-2 inhibitors with other branches of cancer therapy. This review summarizes the pathological roles of the BCL-2 family members in cancer, discusses the current landscape of their targeting in clinical practice, and highlights the potential for future therapeutic inroads in this important area.

Long non-coding RNA FLJ33360 participates in ovarian cancer progression by sponging miR-30b-3p

Background

Long noncoding RNAs (lncRNAs) have been reported to play a key role in the development and progression of human malignancies. FLJ33360 is an lncRNA with unknown functions. This study was designed to determine the clinical significance and mechanism of FLJ33360 in ovarian cancer.

Materials and methods

The clinical significance of FLJ33360 in ovarian cancer was determined using the Gene Expression Profiling Interactive Analysis (GEPIA) database, Kaplan-Meier Plotter database, quantitative reverse transcription polymerase chain reaction (qRT-PCR) and statistical analysis. The regulatory relationships between FLJ33360 and miR-30b-3p were explored through bioinformatics, the Gene Expression Omnibus (GEO) database, the ArrayExpress database and meta-analysis. The possible pathways were predicted using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. In addition, the key target genes were identified using a protein-protein interaction (PPI) network, the Cancer Genome Atlas (TCGA) database, and correlation analysis.

Results

FLJ33360 expression was significantly downregulated in ovarian cancer tissue (P=0.0011) and was closely associated with International Federation of Gynecology and Obstetrics (FIGO) stage (P=0.027) and recurrence (P=0.002). FLJ33360 may have potential value in detecting ovarian cancer (area under the curve =0.793). Function analysis demonstrated that FLJ33360 can act as a molecular sponge of miR-30b-3p to regulate the expression of target genes that are mainly involved in positive regulation of smooth muscle cell migration, the unsaturated fatty acid metabolic process, and positive regulation of the epithelial to mesenchymal transition. Among these target genes, BCL2 is the hub gene.

Conclusion

FLJ33360 is a potential biomarker for early diagnosis and prognostic assessment in ovarian cancer and may regulate the expression of genes by sponging miR-30b-3p and thus participate in the development of ovarian cancer.

Lower expression of Bax predicts poor clinical outcome in patients with glioma after curative resection and radiotherapy/chemotherapy

BACKGROUND

The prognosis in patients with gliomas after surgical resection followed by radiotherapy and/or chemotherapy is still very poor. The pro-apoptotic protein Bax, a short-lived protein in cancers, plays important roles in the sensitivity of glioma cells to spontaneous and therapy-induced apoptosis but and its prognostic value in gliomas is unknown.

METHODS

By an immunohistochemical method, we determined Bax protein expression from 96 patients with gliomas after curative resection. Two statistical analyses were performed to evaluate the prognostic significance of Bax protein: an independent continuous and a multivariate categorical analysis, with test/validation set-defined cut points, and Kaplan-Meier estimated outcome measures of overall survival (OS) and relapse-free survival (RFS).

RESULTS

Bax protein levels in glioblastoma were significantly decreased compared with grade II gliomas. Lower levels of Bax expression confer worse OS (continuous P = 0.025; categorical P = 0.003) and RFS (continuous P = 0.014; categorical P < 0.0001) and negatively correlate with the grades of gliomas. Patients underwent radiotherapy followed by surgical resection showed significantly increased OS (median = 45 vs. 17 months) and RFS (median = 39 vs. 16 months). Patients with higher levels of Bax and radiotherapy showed greatly increased survival rates (median OS = 66 months and median RFS = 105 months). Lower expression of Bax also confers inferior clinical outcome for gliomas patients after chemotherapy with temozolomide (OS and RFS P < 0.0001).

CONCLUSION

Decreased expression of Bax correlates with poor clinical outcome in patients with gliomas. We propose that Bax protein levels can be used as a reliable prognostic marker for risk-stratify patients with gliomas after curative resection and radiotherapy and/or chemotherapy.

Nanoformulations of doxorubicin: how far have we come and where do we go from here?

Nanotechnology, focused on discovery and development of new pharmaceutical products is known as nanopharmacology, and one research area this branch is engaged in are nanopharmaceuticals. The importance of being nano has been particularly emphasized in scientific areas dealing with nanomedicine and nanopharmaceuticals. Nanopharmaceuticals, their routes of administration, obstacles and solutions concerning their improved application and enhanced efficacy have been briefly yet comprehensively described. Cancer is one of the leading causes of death worldwide and evergrowing number of scientific research on the topic only confirms that the needs have not been completed yet and that there is a wide platform for improvement. This is undoubtedly true for nanoformulations of an anticancer drug doxorubicin, where various nanocarrriers were given an important role to reduce the drug toxicity, while the efficacy of the drug was supposed to be retained or preferably enhanced. Therefore, we present an interdisciplinary comprehensive overview of interdisciplinary nature on nanopharmaceuticals based on doxorubicin and its nanoformulations with valuable information concerning trends, obstacles and prospective of nanopharmaceuticals development, mode of activity of sole drug doxorubicin and its nanoformulations based on different nanocarriers, their brief descriptions of biological activity through assessing in vitro and in vivo behavior.

Phosphorylation switches Bax from promoting to inhibiting apoptosis thereby increasing drug resistance

Akt is a pro‐survival kinase frequently activated in human cancers and is associated with more aggressive tumors that resist therapy. Here, we connect Akt pathway activation to reduced sensitivity to chemotherapy via Akt phosphorylation of Bax at residue S184, one of the pro‐apoptotic Bcl‐2 family proteins required for cells to undergo apoptosis. We show that phosphorylation by Akt converts the pro‐apoptotic protein Bax into an anti‐apoptotic protein. Mechanistically, we show that phosphorylation (i) enables Bax binding to pro‐apoptotic BH3 proteins in solution, and (ii) prevents Bax inserting into mitochondria. Together, these alterations promote resistance to apoptotic stimuli by sequestering pro‐apoptotic activator BH3 proteins. Bax phosphorylation correlates with cellular resistance to BH3 mimetics in primary ovarian cancer cells. Further, analysis of the TCGA database reveals that 98% of cancer patients with increased BAX levels also have an upregulated Akt pathway, compared to 47% of patients with unchanged or decreased BAX levels. These results suggest that in patients, increased phosphorylated anti‐apoptotic Bax promotes resistance of cancer cells to inherent and drug‐induced apoptosis.

Molecular mechanisms for tumour resistance to chemotherapy

Chemotherapy is one of the prevailing methods used to treat malignant tumours, but the outcome and prognosis of tumour patients are not optimistic. Cancer cells gradually generate resistance to almost all chemotherapeutic drugs via a variety of distinct mechanisms and pathways. Chemotherapeutic resistance, either intrinsic or acquired, is caused and sustained by reduced drug accumulation and increased drug export, alterations in drug targets and signalling transduction molecules, increased repair of drug-induced DNA damage, and evasion of apoptosis. In order to better understand the mechanisms of chemoresistance, this review highlights our current knowledge of the role of altered drug metabolism and transport and deregulation of apoptosis and autophagy in the development of tumour chemoresistance. Reduced intracellular activation of prodrugs (e.g. thiotepa and tegafur) or enhanced drug inactivation by Phase I and II enzymes contributes to the development of chemoresistance. Both primary and acquired resistance can be caused by alterations in the transport of anticancer drugs which is mediated by a variety of drug transporters such as P-glycoprotein (P-gp), multidrug resistance associated proteins, and breast cancer resistance protein. Presently there is a line of evidence indicating that deregulation of programmed cell death including apoptosis and autophagy is also an important mechanism for tumour resistance to anticancer drugs. Reversal of chemoresistance is likely via pharmacological and biological approaches. Further studies are warranted to grasp the full picture of how each type of cancer cells develop resistance to anticancer drugs and to identify novel strategies to overcome it.

Prognostic Significance of Apoptosis-related Markers in Patients With Soft-Tissue Sarcomas of Extremities

Bcl-2 and Bax proteins are key regulators of apoptosis, a process that is deregulated in many human diseases, particularly cancer. Overexpression of antiapoptotic Bcl-2 protein is associated with drug resistance and poor clinical outcome in cancer patients, whereas the expression of proapoptotic Bax protein, commonly detected in soft-tissue sarcoma (STS), is often associated with chemiosensitivity in different tumors. Studies on the clinical implications of apoptosis-related markers Bcl-2 and Bax in STS are limited. In this study, immunohistochemistry for Bcl-2 and Bax was performed on tissue microarrays of 86 multiple types of adult STS of the extremities. Bcl-2 and Bax positive expression was detected in 25.9% and 66.7% of the sarcomas, respectively. Overexpression of both, Bcl-2 and Bax, was directly associated with histologic grade and clinical stage. A significant association between Bax and Bcl-2 expression was also observed (P=0.007). The 5-year overall survival for the group was 57%, and it was lower for cases that overexpressed Bcl-2 (47.6% vs. 58.3%) and Bax (50% vs. 66.7%), although not statistically significant. After multivariate analysis, only the high histologic grade appeared as an independent prognostic factor for the patients (P=0.043; HR=8.0; 95% CI, 1.1-60.1). In our study, Bcl-2 and Bax expression was significantly associated with histologic grade and clinical stage, which are classic factors of poor prognosis. We suggest the use of these proteins as potential prognostic markers in STS of extremities.

Cytotoxicity and Apoptotic Effects of Polyphenols from Sugar Beet Molasses on Colon Carcinoma Cells in Vitro

Three polyphenols were isolated and purified from sugar beet molasses by ultrasonic-aid extraction and various chromatographic techniques, and their structures were elucidated by spectral analysis. Cytotoxicity and the molecular mechanism were measured by methyl thiazolyl tetrazolium (MTT) assay, flow cytometry, caspase-3 activity assay and Western blot assay. The results showed that gallic acid, cyanidin-3-O-glucoside chloride and epicatechin have cytotoxicity to the human colon, hepatocellular and breast cancer cells. Cyanidin-3-O-glucoside chloride showed its cytotoxicity against various tumor cell lines, particularly against colon cancer Caco-2 cells with half maximal inhibitory concentration (IC₅₀) value of 23.21 ± 0.14 μg/mL in vitro. Cyanidin-3-O-glucoside chloride may be a potential candidate for the treatment of colon cancer. In the mechanism study, cyanidin-3-O-glucoside chloride increased the ratio of cell cycle at G₀/G₁ phase and reduced cyclin D1 expression on Caco-2 cells. Cyanidin-3-O-glucoside chloride decreased mutant p21 expression, and increased the ratio of Bax/Bcl-2 and the activation of caspase-3 to induce apoptosis.

APOBEC3G Expression Correlates with T-Cell Infiltration and Improved Clinical Outcomes in High-grade Serous Ovarian Carcinoma

PURPOSE

APOBEC3 DNA cytosine deaminase family members normally defend against viruses and transposons. However, deregulated APOBEC3 activity causes mutations in cancer. Because of broad expression profiles and varying mixtures of normal and cancer cells in tumors, including immune cell infiltration, it is difficult to determine where different APOBEC3s are expressed. Here, we ask whether correlations exist between APOBEC3 expression and T-cell infiltration in high-grade serous ovarian cancer (HGSOC), and assess whether these correlations have prognostic value.

EXPERIMENTAL DESIGN

Transcripts for APOBEC3G, APOBEC3B, and the T-cell markers, CD3D, CD4, CD8A, GZMB, PRF1, and RNF128 were quantified by RT-qPCR for a cohort of 354 HGSOC patients. Expression values were correlated with each other and clinical parameters. Two additional cohorts were used to extend HGSOC clinical results. Immunoimaging was used to colocalize APOBEC3G and the T-cell marker CD3. TCGA data extended expression analyses to additional cancer types.

RESULTS

A surprising positive correlation was found for expression of APOBEC3G and several T cell genes in HGSOC. Immunohistochemistry and immunofluorescent imaging showed protein colocalization in tumor-infiltrating T lymphocytes. High APOBEC3G expression correlated with improved outcomes in multiple HGSOC cohorts. TCGA data analyses revealed that expression of APOBEC3D and APOBEC3H also correlates with CD3D across multiple cancer types.

CONCLUSIONS

Our results identify APOBEC3G as a new candidate biomarker for tumor-infiltrating T lymphocytes and favorable prognoses for HGSOC. Our data also highlight the complexity of the tumor environment with respect to differential APOBEC family gene expression in both tumor and surrounding normal cell types. Clin Cancer Res; 22(18); 4746-55. ©2016 AACR.

Engineered Nanoparticles Against MDR in Cancer: The State of the Art and its Prospective

Cancer is a highly heterogeneous disease at intra/inter patient levels and known as the leading cause of death worldwide. A variety of mono and combinational therapies including chemotherapy have been evolved over the years for its effective treatment. However, advent of chemotherapeutic resistance or multidrug resistance (MDR) in cancer is a major challenge researchers are facing in cancer chemotherapy. MDR is a complex process having multifaceted non-cellular or cellular-based mechanisms. Research in the area of cancer nanotechnology over the past two decade has now proven that the smartly designed nanoparticles help in successful chemotherapy by overcoming the MDR and preferentially accumulate in the tumor region by means of active and passive targeting therefore reducing the offtarget accumulation of payload. Many of such nanoparticles are in different stages of clinical trials as nanomedicines showing promising result in cancer therapy including the resistant cases. Nanoparticles as chemotherapeutics carriers offer the opportunity to have multiple payload of drug and or imaging agents for combinational and theranostics therapy. Moreover, nanotechnology further bring in notice the new treatment strategies such as combining the NIR, MRI and HIFU in cancer chemotherapy and imaging. Here, we discussed the cellular/non-cellular factors constituting the MDR in cancer and the role of nanomedicines in effective chemotherapy of MDR cases of cancers. Moreover, recent advancements like combinational payload delivery and combined physical approach with nanotechnology in cancer therapy have also been discussed.

Oncogenes associated with drug resistance in ovarian cancer

PURPOSE

Oncogenes play pivotal roles in the development of cancer, and disturbances in their expression have been implicated in drug resistance. However, an overview of the contribution of oncogenes to drug resistance in ovarian cancer has not previously been reported. This study aimed to review the drug resistance-related oncogenes in ovarian cancer and precisely determine their relationships.

METHODS

The oncogenes associated with drug resistance in ovarian cancer from available papers were summarized, and a comprehensive bioinformatics analysis including pathway enrichment, biological processes annotation, protein/gene interaction and microRNA-mRNA interaction was performed.

RESULTS

Total of 25 oncogenes contributing to drug resistance in ovarian cancer was integrated and further analyzed. An oncogene-mediated drug resistance pathway that explains the associations of 21 of these oncogenes in drug resistance was drafted on the basis of previously published papers. The downstream location of v-akt murine thymoma viral oncogene (AKT) and B-cell CLL/lymphoma 2-associated X protein (BAX) with respect to many other oncogenes was determined, indicating that the two genes may play a central role, and the AKT- and BAX-mediated signaling are the main pathways accounting for the involvement of oncogenes in drug resistance in ovarian cancer. Besides, the annotation of biological process indicated that the apoptosis (cell death) and phosphorylation (phosphate metabolic process) might be the two major biological routes through which oncogenes contribute to drug resistance in ovarian cancer. In addition, on the basis of the comprehensive analysis of microRNA-mRNA interactions, 11 microRNAs were identified to be targeted at least 7 of the 25 oncogenes, indicating that those microRNAs could be an important regulator of the 25 oncogenes. Collectively, by integrating and further analyzing the available data on these oncogenes, this study contributes to improving our understanding of the mechanisms by which their expression leads to drug resistance in this ovarian cancer.

The combination of thioxodihydroquinazolinones and platinum drugs reverses platinum resistance in tumor cells by inducing mitochondrial apoptosis independent of Bax and Bak

The effective management of tumors resistant to platinum drugs-based anticancer therapies is a critical challenge in current clinical practices. The proapoptotic Bcl-2 family proteins Bax and Bak are essential for cisplatin-induced apoptosis. Unfortunately, Bax and its related upstream endogenous apoptotic signaling pathways are often dysregulated in cancer cells. Strategies that are able to bypass Bax- and Bak-dependent apoptotic pathways will thus provide opportunities to overcome platinum drug resistance. We have identified the thioxodihydroquinazolinone mdivi-1 as a member of a novel class of small molecules that are able to induce Bax- and Bak-independent mitochondrial outer membrane permeabilization when combined with cisplatin, thereby efficiently triggering apoptosis in platinum-resistant tumor cells. In the present structure activity relationship (SAR) study of a computationally selected library of mdivi-1 related small molecules, we established a pharmacophore model that can lead to the enhancement of platinum drug efficacy and Bax/Bak-independent mitochondrial apoptosis. Specifically, we found that a thiourea function is necessary but not sufficient for the synergism of this class of thioxodihydroquinazolinones with cisplatin. We were also able to identify more potent mdivi-1 analogs through this SAR study, which will guide future designs with the goal to develop novel combination regimens for the treatment of platinum- and multidrug-resistant tumors.

Pathway modulations and epigenetic alterations in ovarian tumorbiogenesis

Cellular pathways are numerous and are highly integrated in function in the control of cellular systems. They collectively regulate cell division, proliferation, survival and apoptosis of cells and mutagenesis of key genes that control these pathways can initiate neoplastic transformations. Understanding these pathways is crucial to future therapeutic and preventive strategies of the disease. Ovarian cancers are of three major types; epithelial, germ-cell, and stromal. However, ovarian cancers of epithelial origin, arising from the mesothelium, are the predominant form. Of the subtypes of ovarian cancer, the high-grade serous tumors are fatal, with low survival rate due to late detection and poor response to treatments. Close examination of preserved ovarian tissues and in vitro studies have provided insights into the mechanistic changes occurring in cells mediated by a few key genes. This review will focus on pathways and key genes of the pathways that are mutated or have aberrant functions in the pathology of ovarian cancer. Non-genetic mechanisms that are gaining prominence in the pathology of ovarian cancer, miRNAs and epigenetics, will also be discussed in the review.

Nanopreparations to overcome multidrug resistance in cancer

Multidrug resistance is the most widely exploited phenomenon by which cancer eludes chemotherapy. Broad variety of factors, ranging from the cellular ones, such as over-expression of efflux transporters, defective apoptotic machineries, and altered molecular targets, to the physiological factors such as higher interstitial fluid pressure, low extracellular pH, and formation of irregular tumor vasculature are responsible for multidrug resistance. A combination of various undesirable factors associated with biological surroundings together with poor solubility and instability of many potential therapeutic small & large molecules within the biological systems and systemic toxicity of chemotherapeutic agents has necessitated the need for nano-preparations to optimize drug delivery. The physiology of solid tumors presents numerous challenges for successful therapy. However, it also offers unique opportunities for the use of nanotechnology. Nanoparticles, up to 400 nm in size, have shown great promise for carrying, protecting and delivering potential therapeutic molecules with diverse physiological properties. In this review, various factors responsible for the MDR and the use of nanotechnology to overcome the MDR, the use of spheroid culture as well as the current technique of producing microtumor tissues in vitro are discussed in detail.

Prognostic significance of several biomarkers in epithelial ovarian cancer: a meta-analysis of published studies

OBJECTIVE

Abnormal expression of several biomarkers might predict disease prognosis and response to chemotherapy in patients with epithelial ovarian cancer (EOC). However, the published data are inconsistent.

METHODS

Eligible studies that investigated the association between survival or response to platinum-based chemotherapy in EOC and the expression status of Bcl-2, EGFR, GST, LRP, p16, p21, P-gp and TNF-α were identified by an electronic search of PubMed and Embase. The measures of interest were hazard ratio (HR) for survival or risk ratio for chemotherapy response. A meta-analysis was performed using the fixed-effect or random-effect models.

RESULTS

The number of eligible studies analyzed was 27 for Bcl-2, 22 for EGFR, 29 for GST, 12 for LRP, 16 for p16, 22 for p21, 27 for P-gp and three for TNF-α. A meta-analysis showed that high EGFR and P-gp expression was associated with poor overall survival (OS) (pooled adjusted HR = 1.826 and HR = 1.822). Only high GST expression was associated with improved OS (HR = 0.780). Furthermore, high p16 and P-gp expression was associated with poor progression-free survival (PFS) (HR = 1.550 and HR = 2.136). High GST expression was associated with improved PFS (HR = 0.689). Among these factors, only LRP, P-gp and TNF-α were associated with response to platinum-based chemotherapy.

CONCLUSIONS

The markers we analyzed are unlikely to be useful as predictors of prognosis and response to platinum-based chemotherapy in EOC patients in clinical practice.

GnRH receptors in cancer: from cell biology to novel targeted therapeutic strategies

The crucial role of pituitary GnRH receptors (GnRH-R) in the control of reproductive functions is well established. These receptors are the target of GnRH agonists (through receptor desensitization) and antagonists (through receptor blockade) for the treatment of steroid-dependent pathologies, including hormone-dependent tumors. It has also become increasingly clear that GnRH-R are expressed in cancer tissues, either related (i.e. prostate, breast, endometrial, and ovarian cancers) or unrelated (i.e. melanoma, glioblastoma, lung, and pancreatic cancers) to the reproductive system. In hormone-related tumors, GnRH-R appear to be expressed even when the tumor has escaped steroid dependence (such as castration-resistant prostate cancer). These receptors are coupled to a G(αi)-mediated intracellular signaling pathway. Activation of tumor GnRH-R by means of GnRH agonists elicits a strong antiproliferative, antimetastatic, and antiangiogenic (more recently demonstrated) activity. Interestingly, GnRH antagonists have also been shown to elicit a direct antitumor effect; thus, these compounds behave as antagonists of GnRH-R at the pituitary level and as agonists of the same receptors expressed in tumors. According to the ligand-induced selective-signaling theory, GnRH-R might assume various conformations, endowed with different activities for GnRH analogs and with different intracellular signaling pathways, according to the cell context. Based on these consistent experimental observations, tumor GnRH-R are now considered a very interesting candidate for novel molecular, GnRH analog-based, targeted strategies for the treatment of tumors expressing these receptors. These agents include GnRH agonists and antagonists, GnRH analog-based cytotoxic (i.e. doxorubicin) or nutraceutic (i.e. curcumin) hybrids, and GnRH-R-targeted nanoparticles delivering anticancer compounds.

Immunohistochemistry with apoptotic-antiapoptotic proteins (p53, p21, bax, bcl-2), c-kit, telomerase, and metallothionein as a diagnostic aid in benign, borderline, and malignant serous and mucinous ovarian tumors

Background

In many tumors including ovarian cancer, cell proliferation and apoptosis are important in pathogenesis and there are many alterations in most of the genes related to the cell cycle. This study was designed to evaluate immunohistochemistry with apoptotic-antiapoptotic proteins (p53, p21, bax, and bcl-2), c-kit, telomerase, and metallothionein as a diagnostic aid in typing of benign, borderline, and malignant serous and mucinous ovarian tumors.

Methods

Total of 68 ovarian tumors, 25 benign [13 (19.1%) serous and12 (17.6%) mucinous], 16 borderline [9 (13.2%) serous and 7(10.3%) mucinous], and 27 malignant ovarian tumors [24 (35.3%) serous and 3 (4.4%) mucinous tumors] were included in the study. Immunohistochemical expression of p53, p21, bax, bcl–2, telomerase, c-kit, and metallothionein were evaluated.

Results

When all 68 cases were evaluated as benign, borderline, and malignant ovarian tumors without considering histopathological subtypes, the p53, p21, bax and metallothionein showed significantly higher staining scores in the borderline and malignant ones (p < 0.05). After evaluation of all 68 cases, the serous tumors showed significantly higher staining scores of p53, p21, c-kit, and metallothionein compared to the mucinous ones (p < 0.05). For differentiation of benign and borderline and malignant tumors combined, p53 was not used because all benign tumors has no staining, and p21, bax, and metallothionein was determined the significant predictors for borderline and malignant tumors combined (p < 0.05). For differentiation of borderline and malignant tumors, only p53 was determined the significant predictor for malignant tumors (p < 0.05).

Conclusions

In conclusion, p53, p21, bax, c-kit, and metallothionein may be helpful for the typing of ovarian tumors as benign, borderline and malignant or serous and mucinous. p53, p21, bax, c-kit, and metallothionein may have different roles in the pathogenesis of ovarian tumor types. p53 and metallothionein may be helpful in the typing of borderline and malignant ovarian tumors. The immunohistochemical staining with bcl-2 and telomerase may not provide meaningful contribution for the typing of ovarian tumors.

Virtual slide

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2013030833768498

Downregulation of KLF4 and the Bcl-2/Bax ratio in advanced epithelial ovarian cancer

Kruppel-like factor 4 (KLF4) is a key transcriptional regulator of cell differentiation and proliferation and an altered expression of KLF4 has been reported in a number of human malignancies. In the present study, we investigated KLF4 expression and its role in cell proliferation in advanced epithelial ovarian cancer (EOC). We compared KLF4, Bcl-2 and Bax transcript levels in ovaries isolated from advanced EOC and normal control ovaries. In addition, the KLF4 gene was transduced into ovarian cancer cells and transcript levels of Bcl-2 and Bax and cell proliferation were analyzed by real-time RT-PCR and MTT assays, respectively. Ovarian KLF4 expression and Bcl-2/Bax ratios were downregulated in most cases of advanced EOC. In addition, KLF4 overexpression in ovarian cancer cells increased the Bcl-2/Bax ratio. However, MTT analysis indicated that the overexpression of KLF4 had no effect on the proliferation of ovarian cancer cells. The inactivation of KLF4 is frequently observed in ovarian cancers and a reduced expression of KLF4 in the ovarian cancers may lead to a reduction in the Bcl-2/Bax ratio. The latter has a role in predicting cancer grade, although its exact role in ovarian carcinogenesis requires clarification.

Implementing an online tool for genome-wide validation of survival-associated biomarkers in ovarian-cancer using microarray data from 1287 patients

The validation of prognostic biomarkers in large independent patient cohorts is a major bottleneck in ovarian cancer research. We implemented an online tool to assess the prognostic value of the expression levels of all microarray-quantified genes in ovarian cancer patients. First, a database was set up using gene expression data and survival information of 1287 ovarian cancer patients downloaded from Gene Expression Omnibus and The Cancer Genome Atlas (Affymetrix HG-U133A, HG-U133A 2.0, and HG-U133 Plus 2.0 microarrays). After quality control and normalization, only probes present on all three Affymetrix platforms were retained (n=22,277). To analyze the prognostic value of the selected gene, we divided the patients into two groups according to various quantile expressions of the gene. These groups were then compared using progression-free survival (n=1090) or overall survival (n=1287). A Kaplan-Meier survival plot was generated and significance was computed. The tool can be accessed online at www.kmplot.com/ovar. We used this integrative data analysis tool to validate the prognostic power of 37 biomarkers identified in the literature. Of these, CA125 (MUC16; P=3.7×10(-5), hazard ratio (HR)=1.4), CDKN1B (P=5.4×10(-5), HR=1.4), KLK6 (P=0.002, HR=0.79), IFNG (P=0.004, HR=0.81), P16 (P=0.02, HR=0.66), and BIRC5 (P=0.00017, HR=0.75) were associated with survival. The combination of several probe sets can further increase prediction efficiency. In summary, we developed a global online biomarker validation platform that mines all available microarray data to assess the prognostic power of 22,277 genes in 1287 ovarian cancer patients. We specifically used this tool to evaluate the effect of 37 previously published biomarkers on ovarian cancer prognosis.

Multifunctional tumor-targeted polymer-peptide-drug delivery system for treatment of primary and metastatic cancers

PURPOSE

In order to improve drug delivery to drug-resistant ovarian tumors, we constructed a multifunctional polymer-peptide-drug conjugate (PPDC) system for effective treatment of primary and metastatic ovarian cancers.

METHODS

The PPDC consists of the poly(Ethylene Glycol) (PEG) polymeric carrier conjugated via citric acid spacers to anticancer drug (Camptothecin, CPT), tumor targeting moiety (LRHR, a synthetic analog of luteinizing hormone-releasing hormone) and a suppressor of cellular antiapoptotic defense (BH3 peptide). To test the conjugates in vitro and in vivo, cancer cells were isolated from tissue samples obtained from patients with ovarian primary tumor and metastatic malignant ascites.

RESULTS

It was found that cells isolated from malignant ascites were more aggressive in terms of tumor growth and more resistant to chemotherapy when compared with those isolated from primary tumors. PPDC containing two copies of drugs and peptides was most efficient in treatment of primary tumors and intraperitoneal metastases. Multiple treatments with this PPDC led to almost complete regression of primary tumor and prevented growth of malignant ascites.

CONCLUSION

The proposed multifunctional polymeric delivery system which consists of multiple copies of the drug and peptides demonstrated significantly higher antitumor activity in primary and metastatic cancers when compared with drug alone and PEG-CPT conjugate.

Predictive and prognostic protein biomarkers in epithelial ovarian cancer: recommendation for future studies

Epithelial ovarian cancer is the most lethal gynecological malignancy. Due to its lack of symptoms, this disease is diagnosed at an advanced stage when the cancer has already spread to secondary sites. While initial rates of response to first treatment is >80%, the overall survival rate of patients is extremely low, mainly due to development of drug resistance. To date, there are no reliable clinical factors that can properly stratify patients for suitable chemotherapy strategies. Clinical parameters such as disease stage, tumor grade and residual disease, although helpful in the management of patients after their initial surgery to establish the first line of treatment, are not efficient enough. Accordingly, reliable markers that are independent and complementary to clinical parameters are needed for a better management of these patients. For several years, efforts to identify prognostic factors have focused on molecular markers, with a large number having been investigated. This review aims to present a summary of the recent advances in the identification of molecular biomarkers in ovarian cancer patient tissues, as well as an overview of the need and importance of molecular markers for personalized medicine in ovarian cancer.

Differential transport of platinum compounds by the human organic cation transporter hOCT2 (hSLC22A2)

BACKGROUND

Solute carriers (SLCs), in particular organic cation transporters (OCTs), have been implicated in the cellular uptake of platinum-containing anticancer compounds. The activity of these carriers may determine the pharmacokinetics and the severity of side effects, including neuro- and nephrotoxicity of platinum-based chemotherapy. As decreased drug accumulation is a key mechanism of platinum resistance, SLCs may also contribute to the development of resistance. Here, we define the role of hSLC22A2 (OCT2) in the cellular uptake of platinum compounds.

EXPERIMENTAL APPROACH

Human embryonic kidney (HEK) 293 cells stably expressing the hSLC22A2 gene (HEK293/hSLC22A2) were used in platinum accumulation studies. Following a 2 h exposure to various platinum compounds (100 microM), intracellular platinum levels were determined by flameless atomic absorption spectrometry.

KEY RESULTS

HEK293/hSLC22A2 cells, compared with HEK293/Neo control cells, displayed significant increases in oxaliplatin (28.6-fold), Pt[DACH]Cl(2) (20.6-fold), ormaplatin (8.1-fold), tetraplatin (4.5-fold), transplatin (3.7-fold) and cisplatin (1.3-fold), but not carboplatin. SLC22A2-mediated transport could be inhibited by 1-methyl-4-phenylpyridinium. Furthermore, hSLC22A2-mediated oxaliplatin and cisplatin accumulation was time- and concentration-dependent, but non-saturable. Expression of hSLC22A2 in HEK293 cells resulted in enhanced sensitivity to oxaliplatin (12-fold) and cisplatin (1.8-fold). Although, hSLC22A2 mRNA expression was frequently found in ovarian cancer cell lines, its expression in clinical ovarian cancer specimens (n= 80) was low and did not correlate with the treatment outcome of platinum-based regimens.

CONCLUSIONS AND IMPLICATIONS

The hSLC22A2 drug transporter is a critical determinant in the uptake and cytotoxicity of various platinum compounds, particularly oxaliplatin.

Modest effect of p53, EGFR and HER-2/neu on prognosis in epithelial ovarian cancer: a meta-analysis

BACKGROUND

P53, EGFR and HER-2/neu are the most frequently studied molecular biological parameters in epithelial ovarian cancer, but their prognostic impact is still unequivocal. We performed a meta-analysis to more precisely estimate their prognostic significance.

METHODS

Published studies that investigated the association between p53, EGFR and HER-2/neu status and survival were identified. Meta-analysis was performed using a DerSimonian-Laird model. Publication bias was investigated using funnel plots and sources of heterogeneity were identified using meta-regression analysis.

RESULTS

A total of 62 studies were included for p53, 15 for EGFR and 20 for HER-2/neu. P53, EGFR and HER-2/neu status had a modest effect on overall survival (pooled HR 1.47, 95% CI 1.33-1.61 for p53; HR 1.65, 95% CI 1.25-2.19 for EGFR and HR 1.67, 95% CI 1.34-2.08 for HER-2/neu). Meta-regression analysis for p53 showed that FIGO stage distribution influenced study outcome. For EGFR and HER-2/neu, considerable publication bias was present.

CONCLUSIONS

Although p53, EGFR and HER-2/neu status modestly influences survival, these markers are, by themselves, unlikely to be useful as prognostic markers in clinical practice. Our study highlights the need for well-defined, prospective clinical trials and more complete reporting of results of prognostic factor studies.

The biology of ovarian cancer: new opportunities for translation

Over the past two decades, the 5-year survival for ovarian cancer patients has substantially improved owing to more effective surgery and treatment with empirically optimized combinations of cytotoxic drugs, but the overall cure rate remains approximately 30%. Many investigators think that further empirical trials using combinations of conventional agents are likely to produce only modest incremental improvements in outcome. Given the heterogeneity of this disease, increases in long-term survival might be achieved by translating recent insights at the molecular and cellular levels to personalize individual strategies for treatment and to optimize early detection.

Survival-related profile, pathways, and transcription factors in ovarian cancer

BACKGROUND

Ovarian cancer has a poor prognosis due to advanced stage at presentation and either intrinsic or acquired resistance to classic cytotoxic drugs such as platinum and taxoids. Recent large clinical trials with different combinations and sequences of classic cytotoxic drugs indicate that further significant improvement in prognosis by this type of drugs is not to be expected. Currently a large number of drugs, targeting dysregulated molecular pathways in cancer cells have been developed and are introduced in the clinic. A major challenge is to identify those patients who will benefit from drugs targeting these specific dysregulated pathways.The aims of our study were (1) to develop a gene expression profile associated with overall survival in advanced stage serous ovarian cancer, (2) to assess the association of pathways and transcription factors with overall survival, and (3) to validate our identified profile and pathways/transcription factors in an independent set of ovarian cancers.

METHODS AND FINDINGS

According to a randomized design, profiling of 157 advanced stage serous ovarian cancers was performed in duplicate using approximately 35,000 70-mer oligonucleotide microarrays. A continuous predictor of overall survival was built taking into account well-known issues in microarray analysis, such as multiple testing and overfitting. A functional class scoring analysis was utilized to assess pathways/transcription factors for their association with overall survival. The prognostic value of genes that constitute our overall survival profile was validated on a fully independent, publicly available dataset of 118 well-defined primary serous ovarian cancers. Furthermore, functional class scoring analysis was also performed on this independent dataset to assess the similarities with results from our own dataset. An 86-gene overall survival profile discriminated between patients with unfavorable and favorable prognosis (median survival, 19 versus 41 mo, respectively; permutation p-value of log-rank statistic = 0.015) and maintained its independent prognostic value in multivariate analysis. Genes that composed the overall survival profile were also able to discriminate between the two risk groups in the independent dataset. In our dataset 17/167 pathways and 13/111 transcription factors were associated with overall survival, of which 16 and 12, respectively, were confirmed in the independent dataset.

CONCLUSIONS

Our study provides new clues to genes, pathways, and transcription factors that contribute to the clinical outcome of serous ovarian cancer and might be exploited in designing new treatment strategies.

Chemotherapy drug response in ovarian cancer cells strictly depends on a cathepsin D-Bax activation loop

The ovarian cancer cell lines A2780 (wild-type p53) and NIHOVCAR3 (mutated p53) showed, respectively, sensitivity and resistance towards several chemotherapy drugs. We hypothesized that the two cell lines differ in their ability to activate the intrinsic death pathway and have, therefore, dissected the lysosome-mitochondrion signalling pathway by pharmacological inhibition or genetic manipulation of key regulators and executioners. Biochemical and morphological confocal fluorescence studies showed that: (1) In A2780 cells bcl-2 is expressed at an undetectable level, whereas Bax is expressed at a rather high level; by contrast, bcl-2 is highly expressed and Bax is expressed at extremely low levels in NIHOVCAR3 cells; (2) Chemotherapy treatment reduced the expression of bcl-2 in NIHOVCAR3 cells, yet these cells resisted to drug toxicity; (3) Cathepsin D (CD), not cathepsin B or L, mediates the activation of the mitochondrial intrinsic death pathway in A2780 cells; (4) Lysosome leakage and cytosolic relocation of CD occurs in the chemosensitive A2780 cells, not in the chemoresistant NIHOVCAR3 cells; (5) Bax is essential for the permeabilization of both lysosomes and mitochondria in A2780 cells exposed to chemotherapy drugs; (6) CD activity is mandatory for the oligomerization of Bax on both mitochondrial and lysosomal membranes; (7) Bax activation did not occur in the resistant NIHOVCAR3 cells despite their high content in CD. The present data are consistent with a model in which on treatment with a cytotoxic drug the activation of a CD-Bax loop leads to the generalized permeabilization of lysosomes and eventually of mitochondria, thus reaching the point of no return, and culminates with the activation of the caspase cascade. Our data also imply that dysfunctional permeabilization of lysosomes contributes to the development of chemoresistance.

Serum and tissue biomarkers as predictive and prognostic variables in epithelial ovarian cancer

Tumour stage, residual disease after initial surgery, histological type and tumour grade are the most important clinical-pathological factors related to the clinical outcome of patients with epithelial ovarian cancer. In the last years, several investigations have assessed different biological variables in sera and in tissue samples from patients with this malignancy in order to detect biomarkers able to reflect either the response to chemotherapy or survival. The present paper reviewed the literature data about the predictive or prognostic relevance of serum CA 125, soluble cytokeratin fragments, serum human kallikreins, serum cytokines, serum vascular endothelial growth factor and plasma d-dimer as well as of tissue expression of cell cycle- and apoptosis-regulatory proteins, human telomerase reverse transcriptase, membrane tyrosine kinase receptors and matrix metalloproteinases. A next future microarray technology will hopefully offer interesting perspectives of translational research for the identification of novel predictive and prognostic biomarkers for epithelial ovarian cancer.

Resistance to chemotherapy in ovarian carcinoma

Resistance to cytotoxic chemotherapy is the main cause of therapeutic failure and death in women suffering from ovarian carcinoma. The standard first-line chemotherapy of ovarian cancer consists of a combination of a taxane and a platinum-containing drug. Thus, the cellular and molecular mechanisms involved in resistance against these compounds are of vital importance in the context of chemotherapy of ovarian cancer. This review will discuss the current state of knowledge of drug resistance-associated factors and their impact on clinical chemotherapy response in ovarian carcinoma as well as different strategies for reversal of drug resistance.

Determination of the mechanism of gemcitabine modulation of cisplatin drug resistance in panel of human endometrial cancer cell lines

OBJECTIVES

The primary objective of this study was to determine the mechanism(s) of cisplatin drug resistance in endometrial cancer cell lines. To evaluate the mechanism that gemcitabine modulates cisplatin drug resistance in endometrial cancer cell lines.

METHODS

Combination treatment was completed in panel of four human endometrial cancer cell lines. Growth inhibition assays were conducted in each cell line evaluating combinations of the Ic25, Ic50, and Ic90 to determine optimal dosing for the combination of gemcitabine plus cisplatin. Evaluation of the correlative biological targets for modulation of platinum drug resistance was completed by the respective immunohistochemistry assays.

RESULTS

Downregulation of glutathione-S-transferase (GST) activity by 11% to 100% was observed with an associated 78.6% to 100% decrease in intracellular glutathione (GSH) concentrations. In the gemcitabine plus cisplatin treatment arm compared to either alone, there was also downregulation of MSH2, p53, and ERCC1 expression. No changes observed in the pro-apoptotic proteins, BAX or BAD, expression, AKT activation, or MDR1/PGP expression regardless of treatment with combination of gemcitabine plus cisplatin or either agent alone.

CONCLUSIONS

There is likely more than one mechanism contributing to the increase synergistic in vitro platinum-resistant cell lines and increase clinical activity that has been observed in patients with platinum-resistant tumors. In this in vitro study, we determined the downregulation of intracellular GST activity and GSH concentration were the predominant mechanisms involved in the modulation of platinum resistance. Downregulation of MSH2, p53 and ERCC1 expression may also contribute to increase cytotoxic activity compared to cisplatin alone.

Alterations in the p53 pathway and prognosis in advanced ovarian cancer: a multi-factorial analysis of the EORTC Gynaecological Cancer group (study 55865)

PURPOSE

The study was designed to determine independent prognostic variables in suboptimally debulked advanced ovarian cancer patients entered in the randomised phase III study EORTC 55865.

EXPERIMENTAL DESIGN

Retrospectively collected paraffin blocks from 169 patients with stages IIb-IV epithelial ovarian cancer, taken at primary debulking surgery, were analysed. All patients were treated with cyclophosphamide and cisplatin (CP), and followed up for a median of 10 years. Expression of p53, bcl-2, P21, Ki-67 and HER-2 status was assessed by immunohistochemistry (IHC).

RESULTS

Expression of p21, a downstream effector of the p53 gene, was found to be a favourable prognostic factor for survival (HR 0.58, CI 0.36-0.94, p=0.025) in addition to FIGO stage (HR 1.54, CI 1.08-2.21, p=or<0.02). For progression free survival (PFS), both p21 (HR 0.52) and Ki-67 (HR 0.6) were significant factors.

CONCLUSION

P21 overexpression is a positive prognostic factor for survival and PFS in advanced ovarian carcinoma with residual lesions of more than 1 cm.

Influence of interval between primary surgery and chemotherapy on short-term survival of patients with advanced ovarian, tubal or peritoneal cancer

OBJECTIVE

To investigate the impact on short-term survival of time between surgery and start of first chemotherapy cycle in patients with advanced ovarian cancer.

METHODS

This prospective, population-based study comprised 371 patients with epithelial ovarian, tubal or peritoneal cancer diagnosed in 2002-2003. All patients underwent primary surgery, followed at different intervals by chemotherapy. The data were derived from notifications to the Norwegian Cancer Registry and included medical, surgical and histopathological records. Kaplan-Meier plots were used to show differences in survival, and Cox regression analysis was used to show the effect of prognostic factors on survival, expressed as hazard ratios (HRs).

RESULTS

No difference in survival between patient groups was seen when time between surgery and start of chemotherapy was divided into quartiles. The group of patients with no residual disease and an interval between surgery and start of chemotherapy equal to or more than 6 weeks had non-significantly worse survival (unadjusted HR = 1.86; adjusted HR = 1.35) than those with an interval of less than 6 weeks. Patients with residual disease after surgery and chemotherapy at an interval of less than 6 weeks had worse short-term survival than patients without residual disease and the same interval before chemotherapy: unadjusted HR = 3.66 (95% CI, 2.09-6.40) and adjusted HR = 2.36 (95% CI, 1.22-4.57).

CONCLUSIONS

The interval between surgery and start of chemotherapy had no major impact on short-term survival after ovarian cancer. Patients might be included in chemotherapy trials when interval between surgery and start of chemotherapy is more than 6 weeks. Any further investigation of a possible effect of interval between surgery and start of chemotherapy should be performed as a randomized trial.

Mismatch repair and treatment resistance in ovarian cancer

BACKGROUND

The treatment of ovarian cancer is hindered by intrinsic or acquired resistance to platinum-based chemotherapy. The aim of this study is to determine the frequency of mismatch repair (MMR) inactivation in ovarian cancer and its association with resistance to platinum-based chemotherapy.

METHODS

We determined, microsatellite instability (MSI) as a marker for MMR inactivation (analysis of BAT25 and BAT26), MLH1 promoter methylation status (methylation specific PCR on bisulfite treated DNA) and mRNA expression of MLH1, MSH2, MSH3, MSH6 and PMS2 (quantitative RT-PCR) in 75 ovarian carcinomas and eight ovarian cancer cell lines

RESULTS

MSI was detected in three of the eight cell lines i.e. A2780 (no MLH1 mRNA expression due to promoter methylation), SKOV3 (no MLH1 mRNA expression) and 2774 (no altered expression of MMR genes). Overall, there was no association between cisplatin response and MMR status in these eight cell lines. Seven of the 75 ovarian carcinomas showed MLH1 promoter methylation, however, none of these showed MSI. Forty-six of these patients received platinum-based chemotherapy (11 non-responders, 34 responders, one unknown response). The resistance seen in the eleven non-responders was not related to MSI and therefore also not to MMR inactivation.

CONCLUSION

No MMR inactivation was detected in 75 ovarian carcinoma specimens and no association was seen between MMR inactivation and resistance in the ovarian cancer cell lines as well as the ovarian carcinomas. In the discussion, the results were compared to that of twenty similar studies in the literature including in total 1315 ovarian cancer patients. Although no association between response and MMR status was seen in the primary tumor the possible role of MMR inactivation in acquired resistance deserves further investigation.

Molecular predictors of response and outcome in ovarian cancer

A major problem in clinical management of patients with epithelial ovarian cancer (EOC) is the largely unpredictable response to first-line treatment and the occurrence of relapse after complete initial response, associated with broad cross-resistance to even structurally dissimilar drugs. During tumor development and progression, multiple genic alterations take place that might contribute specifically to the treatment response and eventually impact on disease outcome. One area of intense research is the identification of molecular markers to accurately assess the prognosis of EOC patients and to define innovative therapeutic strategies. A large survey of recent published data indicates the need to revisit traditional molecular markers with respect to their contribution to the assessment of overall survival in selected populations. Furthermore, recent technological developments that enable simultaneous measurement of many parameters ("omic" approaches) hold the promise of identifying new molecular prognostic and predictive markers.

Histopathology of BRCA1- and BRCA2-associated breast cancer

Hereditary breast carcinomas that are attributable to BRCA1/2 mutations have their own morphological and immunohistochemical characteristics. BRCA1-associated carcinomas are poorly differentiated infiltrating ductal carcinomas that frequently show morphological features of typical or atypical medullary carcinoma. BRCA2-associated breast carcinomas tend to be of higher grade than sporadic age-matched controls. BRCA1tumors have been found to be more frequently estrogen receptor- and progesterone receptor-negative, and p53-positive than are age-matched controls, whereas these differences are not usually found in BRCA2-associated tumors. In addition, BRCA1- and BRCA2-associated breast carcinomas show a low frequency of HER2 expression. Most BRCA1 breast carcinomas are characterized by the expression of basal (myoepithelial) markers, such as cytokeratin 5/6 and or P-cadherin. These features could be used to distinguish patients who are likely to carry a BRCA1 or BRCA2 germline mutation, thus indicating which gene should be screened for first in families with a high incidence of breast and ovarian cancer.

Molecular targeting of BCL2 and BCLXL proteins by synthetic BCL2 homology 3 domain peptide enhances the efficacy of chemotherapy

Chemotherapeutic agents are known to induce programmed cell death or apoptosis. The activation of cellular antiapoptotic defense that prevents the translation of drug-induced damage into cell death is the key factor in cellular antiapoptotic resistance that decreases the chemotherapeutic effectiveness of a broad spectrum of anticancer drugs. A novel proapoptotic anticancer drug delivery system (DDS) was designed to simultaneously induce apoptosis and suppress antiapoptotic cellular defense. The system includes three main components: 1) anticancer drug camptothecin (CPT) as an apoptosis inducer, 2) synthetic BCL2 homology 3 domain (BH3) peptide as a suppressor of cellular antiapoptotic defense, and 3) poly(ethylene glycol) (PEG) polymer as a carrier. The above DDS was studied in vitro using A2780 human ovarian carcinoma cells and in vivo on nude mice bearing xenografts of human ovarian tumor. The results obtained in both series of experiments corroborate each other. They show that the designed DDS provided intracellular delivery of active components and suppressed cellular antiapoptotic defense, leading to the more pronounced induction of caspase-dependent signaling pathway of apoptosis compared with CPT alone and simple CPT-PEG conjugate. Including BH3 peptide in complex DDS decreased apoptotic cellular defense, substantially increased toxicity of the whole complex, and provided high antitumor activity. Therefore, the proposed novel multicomponent proapoptotic anticancer drug delivery system has high potential to enhance the efficacy of chemotherapy.

Cyclin-dependant kinase inhibitors CIP1 (p21) and KIP1 (p27) in ovarian cancer

PURPOSE

Deregulation of the cell cycle is one of the important prerequisites for cancer development. p21 and p27 are both universal inhibitors of cyclin-dependent kinases and can therefore influence cell cycle or tumor progression. The aim of this study was to determine the influence of p21 and p27 expression on survival and chemotherapy response.

METHODS

165 patients with ovarian cancer have been examined for p21 and p27 expression by immunohistochemistry on formalin-fixed, paraffin-embedded tissue using the monoclonal primary antibody WAF1 (Oncogene Science) and KIP1 (Transduction Laboratories).

RESULTS

High p21 expression (>50%) correlates only with early tumor stage (P=0.04). There was no correlation found between p21 and p27 expression. Patients with high p27 expression (>25%) had a longer DFS (disease free survival) in both univariate and multivariate analysis (P=0.05 and P=0.043) than patients with low p27 expression. A longer overall survival (OS) could only be proven for the group of high p27 expression in univariate analysis (P=0.03).

CONCLUSION

p27 is an independent prognostic factor for ovarian cancer for DFS though this was not true for OS.