Prognostic analysis of triple-negative breast cancer patients treated with adjuvant chemotherapy of fluorouracil, epirubicin and cyclophosphamide

MicroRNA-941 regulates the proliferation of breast cancer cells by altering histone H3 Ser 10 phosphorylation

Breast cancer including triple negative breast cancer (TNBC) represents an important clinical challenge, as these tumours often develop resistance to conventional chemotherapeutics. MicroRNAs play a crucial role in cell-cycle regulation, differentiation, apoptosis, and migration. Herein, we performed Affymetrix Gene Chip miRNA 4.0 microarray and observed differential regulation of miRNAs (75 upregulated and 199 downregulated) in metastatic MDA-MB-231 cells as compared to immortalized human non-tumorigenic breast epithelial (MCF-10A) cells. MicroRNA-941 was significantly upregulated in MDA-MB-231 cells (almost nine-fold increase) in comparison to MCF-10A cells. Transfection of MiRNA-941 inhibitor significantly decreased the proliferation and migration of MDA-MB-231 cells by altering the expressions of p21, Cyclin D1, PP2B-B1, E-cadherin and MMP-13. Interestingly, we provide first evidence that inhibiting miR-941 prevents cell proliferation and phosphorylation of histone H3 at Ser10 residue. Xenograft model of breast cancer was developed by subcutaneous injection of MDA-MB-231 cells into the mammary fat pad of female athymic nude mice (Crl:NU-Foxn1nu). The tumours were allowed to grow to around 60 mm³, thereafter which we divided the animals into seven groups (n = 5). Notably, intratumoral injection of miR-941 inhibitor significantly abolished the tumour growth in MDA-MB-231 xenograft model. 5-Fluorouracil (10 mg/kg, i.p.) was used as positive control in our study. To the best of our knowledge, we report for the first time that targeting miR-941 improves the sensitivity of MDA-MB-231 cells to 5-fluorouracil. This can be of profound clinical significance, as it provides novel therapeutic approach for treating variety of cancers (overexpressing miRNA-941) in general and breast cancers in particular.

Clinicopathological and Prognostic Characteristics of Malaysian Triple Negative Breast Cancer Patients Undergoing TAC Chemotherapy Regimen

Triple negative breast cancer (TNBC) is associated with aggressive tumour phenotype and early tumour relapse following diagnosis. Generally, clinicopathological features such as tumour size, patient's age at diagnosis, tumour histology subtypes, grade and stage, involvement of lymph nodes, and menopausal status are commonly used for predicting disease progression, prospects of recurrence, and treatment response. Prognostic value of clinicopathological features on Malaysian TNBC patients is limited. Thus, this study is aimed at investigating the association of clinicopathological features on disease-free survival (DFS) and overall survival (OS) of Malaysian TNBC patients undergoing TAC chemotherapy. Seventy-six (76) immunohistochemistry-confirmed TNBC patients were recruited. The clinicopathological features of TNBC patients were collected and recorded. Kaplan-Meier and log-rank followed by a Cox proportional hazard regression model were performed to evaluate the TNBC patients' survival. Out of 76 TNBC patients, 25 were chemoresistant and 51 were chemoresponders to the TAC chemotherapy regimen. The overall 5-year cumulative DFS and OS of TNBC patients were 63.5% and 76.3%, respectively. Multivariate Cox analysis demonstrated that medullary and metaplastic histology subtypes and positive axillary lymph node metastasis were significant prognostic factors associated with relapse with adjusted HR: 5.76, 95% CI: 2.35, 14.08 and adjusted HR: 3.55, 95% CI: 1.44, 8.74, respectively. Moreover, TNBC patients with medullary and metaplastic histology subtypes and positive axillary lymph node metastases had a higher risk to death than patients who had infiltrating ductal carcinoma and negative axillary lymph node metastasis (adjusted HR: 8.30, 95% CI: 2.38, 28.96 and adjusted HR: 6.12, 95% CI: 1.32, 28.42, respectively). Our results demonstrate the potential use of medullary and metaplastic histology subtype and positive axillary lymph node metastasis as a potential biomarker in predicting relapse and survival of the TNBC patients. This warrants further studies on intensification of chemotherapy and also identification and development of targeted therapy to reduce relapses and improve survival of TNBC patients.

Dancing from bottoms up - Roles of the POZ-ZF transcription factor Kaiso in Cancer

The POZ-ZF transcription factor Kaiso was discovered two decades ago as a binding partner for p120^ctn. Since its discovery, roles for Kaiso in diverse biological processes (epithelial-to-mesenchymal transition, apoptosis, inflammation) and several signalling pathways (Wnt/β-catenin, TGFβ, EGFR, Notch) have emerged. While Kaiso's biological role in normal tissues has yet to be fully elucidated, Kaiso has been increasingly implicated in multiple human cancers including colon, prostate, ovarian, lung, breast and chronic myeloid leukemia. In the majority of human cancers investigated to date, high Kaiso expression correlates with aggressive tumor characteristics including proliferation and metastasis, and/or poor prognosis. More recently, interest in Kaiso stems from its apparent correlation with racial disparities in breast and prostate cancer incidence and survival outcomes in people of African Ancestry. This review discusses Kaiso's role in various cancers, and Kaiso's potential for driving racial disparities in incidence and/or outcomes in people of African ancestry.

Gene expression profiling of brain metastatic cell from triple negative breast cancer: Understanding the molecular events

Brain metastatic triple negative breast cancer (BM-TNBC) is afflicted with unfavorable prognosis. However, the molecular events underlying BM-TNBC remain largely unknown. In the present study, we conducted gene expression microarray analysis using the triple negative breast cancer cell line MDA-MB-231 and its brain metastatic derivative (MDA-MB-231Brm). Results of microarray analysis showed that a total of 4296 genes were differentially expressed, of which 2433 genes were up-regulated and 1863 genes were down-regulated. Gene Ontology (GO), KEGG pathway and protein-protein interaction (PPI) analyses indicated differentially expressed genes functionally categorized as genes of signal transduction, multicellular organismal development, ion transport, nervous system development, plasma membrane, extracellular region, calcium ion binding, GTP binding neuroactive ligand-receptor interaction. The validity of the microarray results was verified by quantitative real-time PCR analysis of twelve representative genes. The present findings revealed molecular basis and events associated with brain metastasis in TNBC, which will potentially contribute to the understanding of underlying mechanism and develop therapeutic targets.