Rab25 is overexpressed in Müllerian serous carcinoma compared to malignant mesothelioma

RAB25 confers resistance to chemotherapy by altering mitochondrial apoptosis signaling in ovarian cancer cells

Ovarian cancer remains one of the most frequent causes of cancer-related death in women. Many patients with ovarian cancer suffer from de novo or acquired resistance to chemotherapy. Here, we report that RAB25 suppresses chemotherapy-induced mitochondrial apoptosis signaling in ovarian cancer cell lines and primary ovarian cancer cells. RAB25 blocks chemotherapy-induced apoptosis upstream of mitochondrial outer membrane permeabilization by either increasing antiapoptotic BCL-2 proteins or decreasing proapoptotic BCL-2 proteins. In particular, BAX expression negatively correlates with RAB25 expression in ovarian cancer cells. BH3 profiling assays corroborated that RAB25 decreases mitochondrial cell death priming. Suppressing RAB25 by means of RNAi or RFP14 inhibitory hydrocarbon-stapled peptide sensitizes ovarian cancer cells to chemotherapy as well as RAB25-mediated proliferation, invasion and migration. Our data suggest that RAB25 is a potential therapeutic target for ovarian cancer.

Pre-analytical issues in effusion cytology

Effusions or body cavity fluids are amongst the most commonly submitted samples to the cytology laboratory. Knowledge of proper collection, storage, preservation and processing techniques is essential to ensure proper handling and successful analysis of the sample. This article describes how the effusions should be collected and proper conditions for submission. The different processing techniques to extract the cellular material and prepare slides satisfactory for microscopic evaluation are described such as direct smears, cytospins, liquid based preparations and cell blocks. The article further elaborates on handling the specimens for additional ancillary testing such as immunostaining and molecular tests, including predictive ones, as well as future research approaches.

The clinical role of epithelial-mesenchymal transition and stem cell markers in advanced-stage ovarian serous carcinoma effusions

We recently identified gene signatures that allow classification of ovarian carcinoma into 5 distinct clinically relevant groups. In the present study, we investigated the clinical role of 10 protein products of the discriminating genes, with focus on epithelial-mesenchymal transition and stem cell markers. Expression of E-cadherin, N-cadherin, P-cadherin, Zeb1, HMGA2, Rab25, CD24, NCAM (CD56), Sox11, and vimentin was assessed in 100 advanced-stage (International Federation of Gynecology and Obstetrics stages III-IV) serous ovarian carcinoma effusions using immunohistochemistry. Results were analyzed for association with clinicopathological parameters, including chemotherapy response, and survival. All 10 proteins were frequently expressed in carcinoma cells. HMGA2 expression was related to older age (P = .015). HMGA2 and NCAM expression was related to stage III disease (P = .011 and P = .023, respectively), and NCAM was overexpressed in peritoneal compared with pleural effusions (P = .001). Vimentin and Zeb1 expression was significantly related to poor chemotherapy response at diagnosis (P = .005 and P = .017, respectively). The associations between NCAM and peritoneal localization and of vimentin and poor chemoresponse were retained after Bonferroni correction. NCAM expression was associated with a trend for shorter overall survival in univariate survival analysis (P = .187), but emerged as an independent prognosticator in Cox multivariate analysis (P = .042). This study identifies vimentin and Zeb1 as markers of poor chemoresponse in metastatic serous ovarian carcinoma effusions and suggests NCAM as potential prognostic marker in metastatic disease. The generally limited prognostic role of the studied markers emphasizes the difficulty in applying data obtained in studies of primary ovarian carcinomas to analyses of ovarian carcinoma effusions, reflecting the unique biology of the latter.

APOA1 mRNA expression in ovarian serous carcinoma effusions is a marker of longer survival

OBJECTIVES

We previously described the overexpression of APOA1 and GPX3 in ovarian/peritoneal serous carcinoma compared with breast carcinoma effusions using gene expression array analysis. The objective of the present study was to validate this finding and to analyze the association between these genes and clinicopathologic parameters, including survival, in advanced-stage ovarian serous carcinoma.

METHODS

APOA1 and GPX3 mRNA expression using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was analyzed in 121 effusions (101 ovarian, 20 breast carcinomas) and 85 solid ovarian carcinoma specimens (43 primary carcinomas, 42 metastases).

RESULTS

APOA1 and GPX3 transcript levels were significantly higher in ovarian carcinoma at all anatomic sites compared with breast carcinoma effusions (P < .001). GPX3 mRNA levels were significantly higher in primary carcinomas and solid metastases from patients who received neoadjuvant chemotherapy compared with chemo-naïve tumors (P = .016). APOA1 and GPX3 mRNA levels in the entire effusion series were unrelated to clinicopathologic parameters. However, higher APOA1 mRNA levels in primary diagnosis pre-chemotherapy effusions were significantly related to better overall survival (P = .045), a finding that retained its significance in Cox multivariate analysis (P = .016).

CONCLUSIONS

APOA1 and GPX3 mRNA levels on qRT-PCR effectively differentiate ovarian from breast carcinoma. APOA1 may be a novel prognostic marker in metastatic serous carcinoma.

Prognostic biomarkers in endometrial and ovarian carcinoma

This article reviews the main prognostic and predictive biomarkers of endometrial (EC) and ovarian carcinoma (OC). In EC, prognosis still relies on conventional pathological features such as histological type and grade, as well as myometrial or lymphovascular space invasion. Estrogen receptor, p53, Ki-67, and ploidy analysis are the most promising biomarkers among a long list of molecules that have been proposed. Also, a number of putative predictive biomarkers have been proposed in molecular targeted therapy. In OC, prognosis is predominantly dependent on disease stage at diagnosis and the extent of residual disease at primary operation. Diagnostic markers which aid in establishing histological type in OC are available. However, not a single universally accepted predictive or prognostic marker exists to date. Targeted therapy has been growingly focused at in recent years, in view of the frequent development of chemoresistance at recurrent disease. The present review emphasizes the crucial role of correct pathological classification and stringent selection criteria of the material studied as basis for any evaluation of biological markers. It further emphasizes the promise of targeted therapy in EC and OC, while simultaneously highlighting the difficulties remaining before this can become standard of care.

Endocytosis and cancer

Endocytosis entails selective packaging of cell-surface proteins, such as receptors for cytokines and adhesion components, in cytoplasmic vesicles (endosomes). The series of sorting events that determines the fate of internalized proteins, either degradation in lysosomes or recycling back to the plasma membrane, relies on intrinsic sequence motifs, posttranslational modifications (e.g., phosphorylation and ubiquitination), and transient assemblies of both Rab GTPases and phosphoinositide-binding proteins. This multicomponent process is enhanced and skewed in cancer cells; we review mechanisms enabling both major drivers of cancer, p53 and Ras, to bias recycling of integrins and receptor tyrosine kinases (RTKs). Likewise, cadherins and other junctional proteins of cancer cells are constantly removed from the cell surface, thereby disrupting tissue polarity and instigating motile phenotypes. Mutant forms of RTKs able to evade Cbl-mediated ubiquitination, along with overexpression of the wild-type forms and a variety of defective feedback regulatory loops, are frequently detected in tumors. Finally, we describe pharmacological attempts to harness the peculiar endocytic system of cancer, in favor of effective patient treatment.

Defining a prognostic marker panel for patients with ovarian serous carcinoma effusion

Advanced-stage ovarian carcinoma is a highly lethal malignancy, yet no widely accepted prognostic panels exist to date in this disease. The objective of this study was to define such panel for patients with ovarian serous carcinoma effusions. The expression by immunohistochemistry and clinical role of 41 previously studied cancer-associated proteins was analyzed in 143 effusions from patients diagnosed as having advanced-stage (International Federation of Gynecology and Obstetrics stages III-IV) ovarian serous carcinoma treated with platinum-based chemotherapy at diagnosis. Survival analyses were performed separately for patients with prechemotherapy and postchemotherapy effusions. In univariate analysis of patients with primary diagnosis prechemotherapy effusions, survivin was associated with longer progression-free survival (P = .03), whereas survivin (P = .009), signal transducer and activator of transcription 5B (P = .011), and p21-activated kinase-1 (P = .04) were markers of longer overall survival. In univariate analysis of patients with disease recurrence postchemotherapy effusions, peroxisome proliferator-activated receptor-γ (P = .004), human leukocyte antigen-G (P = .013), mammalian target of rapamycin (P = .04), and nucleus accumbens 1 (NAC-1) (P = .046) were associated with poor progression-free survival, whereas peroxisome proliferator-activated receptor-γ (P = .013), claudin-3 (P = .019), activator protein-2γ (P = .04), insulin-like growth factor-2 (P = .04), claudin-7 (P = .042), and fatty acid synthase (P = .048) were markers of poor overall survival. In Cox multivariate analysis for prechemotherapy cases, survivin and fatty acid synthase were independent predictors of better progression-free survival (P = .006 and P = .048, respectively), and signal transducer and activator of transcription 5B and heat shock protein 90 were independently associated with better overall survival (P = .033 and P = .006, respectively). None of the biological markers was an independent prognostic factor in recurrent disease. The present study represents the first attempt at prognostic stratification of multiple tumor markers in one cohort of patients with ovarian serous carcinoma effusions.

Rab25 in cancer: a brief update

Derailed endocytosis is a hallmark of cancer. The endocytic pathway, as demonstrated by our laboratory, is a frequent target of genomic aberrations in cancer and plays a critical role in the maintenance of cellular polarity, stem cell function, bioenergetics, proliferation, motility, invasion, metastasis, apoptosis and autophagy. The Rab GTPases, along with their effectors, are critical regulators of this endocytic machinery and can have a huge impact on the cellular itinerary of growth and metabolism. Rab25 is an epithelial-cell-specific member of the Rab GTPase superfamily, sharing close homology with Rab11a, the endosomal recycling Rab GTPase. RAB25 has been implicated in various cancers, with reports presenting it as both an oncogene and a tumour-suppressor gene. At the cellular level, Rab25 was shown to contribute to invasiveness of cancer cells by regulating integrin trafficking. Recently, our laboratory uncovered a critical role for Rab25 in cellular energetics. Assimilating all of the existing evidence, in the present review, we give an updated overview of the complex and often context-dependent role of Rab25 in cancer.

AZGP1 and SPDEF mRNA expression differentiates breast carcinoma from ovarian serous carcinoma

The ANPEP, AZGP1, and SPDEF genes were previously found to be overexpressed in breast compared to ovarian carcinoma effusions. The present study validated this finding in a larger cohort consisting of both primary and metastatic tumors. ANPEP, AZGP1, and SPDEF mRNA expression was investigated in 83 breast carcinomas (57 primary carcinomas and 26 effusions) and 40 ovarian carcinomas (20 primary carcinomas and 20 effusions) using qPCR. ANPEP protein expression was immunohistochemically analyzed in 53 breast carcinoma effusions and patient-matched primary carcinomas (n = 25) and lymph node metastases (n = 16). mRNA and protein levels were studied for association with tumor type and anatomic site, and for clinical role in breast carcinoma. AZGP1 and SPDEF mRNA was overexpressed in breast compared to ovarian carcinoma (both p < 0.001). AZGP1 mRNA was overexpressed in primary breast carcinoma compared to effusions (p < 0.001), with opposite findings for ANPEP (p = 0.044). AZGP1 mRNA expression correlated with positive ER status (p = 0.032) and grade 1 histology (p = 0.011), whereas SPDEF mRNA levels were associated with positive ER (p = 0.002) and PR (p = 0.013) status and tamoxifen treatment (p = 0.004). ANPEP protein expression was higher in breast carcinoma effusions compared to primary tumors and lymph node metastases (both p = 0.001). ANPEP, AZGP1, and SPDEF levels were unrelated to disease-free or overall survival. This is the first study documenting ANPEP, AZGP1, and SPDEF expression in breast carcinoma effusions. AZGP1 and SPDEF may be novel molecular markers for the differentiation of breast from ovarian carcinoma. ANPEP may be involved in breast carcinoma progression in view of its overexpression in effusions compared to solid specimens.

Increased Rab25 expression is not correlated with peritoneal metastasis of ovarian cancers

Ovarian cancer is the leading cause of death in gynecological cancer. Studies suggested Rab25 is involved in the pathogenesis of ovarian cancers. We here investigated the expression of Rab25 is in all ovarian cancers and whether the expression of Rab25 is associated with peritoneal metastasis. Fifty-nine ovarian cancer patients were included and the levels of Rab25 measured by immunohistochemistry. Our data showed Rab25 was highly expressed in all subtypes of epithelial ovarian cancers, and two subtypes of germ cell tumors, but not in sex cord stromal tumors. Furthermore, the Rab25 expression was not correlated with peritoneal metastasis of ovarian cancer.