MRP2 (ABCC2, cMOAT) expression in nuclear envelope of primary fallopian tube cancer cells is a new unfavorable prognostic factor

The Relationship Between Actin Cytoskeleton and Membrane Transporters in Cisplatin Resistance of Cancer Cells

Cisplatin [cis-diamminedichloroplatinum (II)] is a platinum-based anticancer drug widely used for the treatment of various cancers. It forms interstrand and intrastrand cross-linking with DNA and block DNA replication, resulting in apoptosis. On the other hand, intrinsic and acquired cisplatin resistance restricts its therapeutic effects. Although some studies suggest that dramatic epigenetic alternations are involved in the resistance triggered by cisplatin, the mechanism is complicated and remains poorly understood. Recent studies reported that cytoskeletal structures regulate cisplatin sensitivity and that activities of membrane transporters contribute to the development of resistance to cisplatin. Therefore, we focus on the roles of actin filaments and membrane transporters in cisplatin-induced apoptosis. In this review, we summarize the relationship between actin cytoskeleton and membrane transporters in the cisplatin resistance of cancer cells.

Emerging role of nuclear factor erythroid 2-related factor 2 in the mechanism of action and resistance to anticancer therapies

Nuclear factor E2-related factor 2 (NRF2), a transcription factor, is a master regulator of an array of genes related to oxidative and electrophilic stress that promote and maintain redox homeostasis. NRF2 function is well studied in in vitro, animal and general physiology models. However, emerging data has uncovered novel functionality of this transcription factor in human diseases such as cancer, autism, anxiety disorders and diabetes. A key finding in these emerging roles has been its constitutive upregulation in multiple cancers promoting pro-survival phenotypes. The survivability pathways in these studies were mostly explained by classical NRF2 activation involving KEAP-1 relief and transcriptional induction of reactive oxygen species (ROS) neutralizing and cytoprotective drug-metabolizing enzymes (phase I, II, III and 0). Further, NRF2 status and activation is associated with lowered cancer therapeutic efficacy and the eventual emergence of therapeutic resistance. Interestingly, we and others have provided further evidence of direct NRF2 regulation of anticancer drug targets like receptor tyrosine kinases and DNA damage and repair proteins and kinases with implications for therapy outcome. This novel finding demonstrates a renewed role of NRF2 as a key modulatory factor informing anticancer therapeutic outcomes, which extends beyond its described classical role as a ROS regulator. This review will provide a knowledge base for these emerging roles of NRF2 in anticancer therapies involving feedback and feed forward models and will consolidate and present such findings in a systematic manner. This places NRF2 as a key determinant of action, effectiveness and resistance to anticancer therapy.

ABC Family Transporters

The transport of specific molecules across lipid membranes is an essential function of all living organisms. The processes are usually mediated by specific transporters. One of the largest transporter families is the ATP-binding cassette (ABC) family. More than 40 ABC transporters have been identified in human, which are divided into 7 subfamilies (ABCA to ABCG) based on their gene structure, amino acid sequence, domain organization, and phylogenetic analysis. Of them, at least 11 ABC transporters including P-glycoprotein (P-GP/ABCB1), multidrug resistance-associated proteins (MRPs/ABCCs), and breast cancer resistance protein (BCRP/ABCG2) are involved in multidrug resistance (MDR) development. These ABC transporters are expressed in various tissues such as the liver, intestine, kidney, and brain, playing important roles in absorption, distribution, and excretion of drugs. Some ABC transporters are also involved in diverse cellular processes such as maintenance of osmotic homeostasis, antigen processing, cell division, immunity, cholesterol, and lipid trafficking. Several human diseases such as cystic fibrosis, sitosterolemia, Tangier disease, intrahepatic cholestasis, and retinal degeneration are associated with mutations in corresponding transporters. This chapter will describe function and expression of several ABC transporters (such as P-GP, BCRP, and MRPs), their substrates and inhibitors, as well as their clinical significance.

Immune oppression array elucidating immune escape and survival mechanisms in uveal melanoma

AIM

To examine the genetic profile of primary uveal melanoma (UM) as compared to UM in immune escape.

METHODS

Dendritic cells (DC) loaded with lysates of UM cells of high metastatic potential were used to stimulate CTLs(CTLs). When CTLs co-cultured with the UM cells, most UM cells could be eliminated. Survival UM cells grew slowly and were considered to be survival variants and examined by a microarray analysis. These differential genes were analyzed further with Venn Diagrams and functions related to immune escape. We additionally examined transcriptional changes of manually selected survival variants of UM cells and of clinical UM samples by quantitative real-time polymerase chain reaction (qRT-PCR), and analyzed the correlation of these expressions and patients' survival.

RESULTS

Gene expression analyses revealed a marked up-regulation of SLAMF7 and CCL22 and a significant down-regulation of KRT10, FXYD3 and ABCC2. The expression of these genes in the relapsed UM was significantly greater than those in primary UM. UM patients with overexpression of these genes had a shorter survival period as compared with those of their underexpression.

CONCLUSION

Gene expression, in particular of SLAMF7, CCL22, KRT10, FXYD3 and ABCC2, differed between primary UM cells and survival variants of UM cells.

Primary Fallopian Tube Carcinoma: A Single-Institution Experience of 101 Cases: A Retrospective Study

OBJECTIVE

This study aimed to identify the prognostic factors for primary fallopian tube carcinoma.

METHODS

A retrospective analysis was conducted of the patients treated with primary surgery and adjuvant chemotherapy at the Obstetrics and Gynecology Hospital of Fudan University from February 2003 to December 2010. Cox proportional hazards model was used for univariate and multivariate survival analysis.

RESULTS

Included in this study were 101 patients with a median follow-up of 64 months and a mean age of 57 years. Latzko triad symptom of abdominal pain, vaginal bleeding or discharge, and palpable pelvic mass was reported in 14 patients, and elevated CA 125 (≥ 35 U/mL) was found in 63. Four patients were classified as grade 1, 31 were grade 2, and 66 were grade 3. The distribution of International Federation of Gynecology and Obstetrics stage was 33 at stage I, 28 at stage II, 39 at stage III, and 1 at stage IV. Ninety patients underwent optimal tumor debulking in which residual tumor was no larger than 1 cm, and 67 patients received no fewer than 6 cycles of postoperative chemotherapy with paclitaxel and carboplatin (TP)-based regimen. Recurrence occurred in 44 patients after a median of 20 months (range, 1-72 months). The 5-year overall survival rate was 67.7%, and the 5-year disease-free survival was 57.4%. Multivariate analysis revealed that International Federation of Gynecology and Obstetrics stage (I-II) [hazard ratio (HR), 2.670; 95% confidence interval (CI), 1.316-5.418; P = 0.007 vs HR, 2.716; 95% CI, 1.416-5.211; P = 0.003], pelvic lymphadenectomy (HR, 0.274; 95% CI, 0.136-0.555; P < 0.001 vs HR, 0.449; 95% CI, 0.227-0.888; P = 0.021), and cycles (≥ 6) of chemotherapy (HR, 0.480; 95% CI, 0.246-0.937; P = 0.031 vs HR, 0.521; 95% CI, 0.276-0.985; P = 0.045) might serve as independent predictors of both overall survival and disease-free survival.

CONCLUSIONS

Preoperative diagnosis of fallopian tube carcinoma is difficult due to the silent course of this neoplasm. Comprehensive surgical staging including pelvic lymphadenectomy followed by adequate cycles of chemotherapy is an important strategy to improve patients' prognosis.

Emerging role of NRF2 in chemoresistance by regulating drug-metabolizing enzymes and efflux transporters

Chemoresistance is a disturbing barrier in cancer therapy, which always results in limited therapeutic options and unfavorable prognosis. Nuclear factor E2-related factor 2 (NRF2) controls the expression of genes encoding cytoprotective enzymes and transporters that protect against oxidative stress and electrophilic injury to maintain intrinsic redox homeostasis. However, recent studies have demonstrated that aberrant activation of NRF2 due to genetic and/or epigenetic mutations in tumor contributes to the high expression of phase I and phase II drug-metabolizing enzymes, phase III transporters, and other cytoprotective proteins, which leads to the decreased therapeutic efficacy of anticancer drugs through biotransformation or extrusion during chemotherapy. Therefore, a better understanding of the role of NRF2 in regulation of these enzymes and transporters in tumors is necessary to find new strategies that improve chemotherapeutic efficacy. In this review, we summarized the recent findings about the chemoresistance-promoting role of NRF2, NRF2-regulated phase I and phase II drug-metabolizing enzymes, phase III drug efflux transporters, and other cytoprotective genes. Most importantly, the potential of NRF2 was proposed to counteract drug resistance in cancer treatment.

Associations of Promoter Methylations and mRNA Expressions of MMP-2, MMP-7 and MMP-9 with Primary Fallopian Tube Carcinoma

OBJECTIVE

To explore the associations of matrix metalloprotease-2 (MMP-2), MMP-7 and MMP-9 methylations and messenger ribonucleic acid (mRNA) expressions with primary fallopian tube carcinoma (PFTC) development and prognosis.

METHODS

We recruited 48 patients with PFTC into the case group and 48 healthy individuals into the control group; PFTC tissues and normal fallopian tube tissues were obtained from subjects in both groups. Methylation specific polymerase chain reaction (PCR), reverse transcription PCR and the immunohistochemical method were used to examine methylation, mRNA expressions and protein expressions of MMP-2, MMP-7 and MMP-9, respectively.

RESULTS

The methylation rates of MMP-2, MMP-7 and MMP-9 in the case group were significantly lower than those in the control group (all p < 0.05); MMP-2, MMP-7 and MMP-9 protein and mRNA expressions of PFTC tissues were enormously higher than those of normal tissues (all p < 0.05); univariate survival analysis indicated that MMP-2 and MMP-9 methylations and their protein expressions were associated with PFTC prognosis (all p < 0.05), which was further confirmed by the Cox regression model (all p < 0.05).

CONCLUSION

The protein and mRNA expressions of MMP-2, MMP-7 and MMP-9 might be related to PFTC, while the methylations and protein expressions of MMP-2 and MMP-9 might be associated with PFTC progression and prognosis.

Annexin A4 is a promising therapeutic target for the treatment of platinum-resistant cancers

INTRODUCTION

Platinum drugs are widely used for the treatment of testicular, bladder, ovarian, colorectal, lung and prostate cancers. With regard to ovarian cancer in particular, the prognosis is poor for tumours that are (or have become) platinum-resistant. Determining the mechanism underlying platinum resistance may aid in the identification of therapeutic targets for the treatment of platinum-resistant tumours.

AREAS COVERED

This review gives an overview of the characteristics and functions of Annexin (Anx) A4, the mechanism of Anx A4-induced platinum resistance, the association between platinum resistance and platinum transporters, recent reports that Anx A4 overexpression promotes the efflux of platinum drugs via platinum transporters and the association between other Anxs and chemoresistance. The reader will gain an understanding of recent studies on the mechanism of Anx A4-induced chemoresistance. Anx A4 represents a therapeutic target for the treatment of Anx A4-overexpressing platinum-resistant tumours.

EXPERT OPINION

Anx A4 is overexpressed in ovarian clear cell carcinoma (CCC), and enhanced Anx A4 expression induces platinum resistance. Recent studies showed that Anx A4 is also associated with platinum resistance in cancers other than ovarian CCC. Furthermore, other Anxs are reportedly associated with chemoresistance, suggesting a relationship between the Anx family and chemoresistance.