Epigenetic regulator MLL2 shows altered expression in cancer cell lines and tumors from human breast and colon

<p>Abstract</p> <p>Background</p> <p>MLL2, an epigenetic regulator in mammalian cells, mediates histone 3 lysine 4 tri-methylation (H3K4me3) through the formation of a multiprotein complex. MLL2 shares a high degree of structural similarity with MLL, which is frequently disrupted in leukemias via chromosomal translocations. However, this structural similarity is not accompanied by functional equivalence. In light of this difference, and previous reports on involvement of epigenetic regulators in malignancies, we investigated MLL2 expression in established cell lines from breast and colon tissues. We then investigated MLL2 in solid tumors of breast and colon by immunohistochemistry, and evaluated potential associations with established clinicopathologic variables.</p> <p>Results</p> <p>We examined MLL2 at both transcript and protein levels in established cell lines from breast and colon cancers. Examination of these cell lines showed elevated levels of MLL2. Furthermore, we also identified incomplete proteolytic cleavage of MLL2 in the highly invasive tumor cell lines. To corroborate these results, we studied tumor tissues from patients by immunohistochemistry. Patient samples also revealed increased levels of MLL2 protein in invasive carcinomas of the breast and colon. In breast, cytoplasmic MLL2 was significantly increased in tumor tissues compared to adjacent benign epithelium (p < 0.05), and in colon, both nuclear and cytoplasmic immunostaining was significantly increased in tumor tissues compared to adjacent benign mucosa (p < 0.05).</p> <p>Conclusion</p> <p>Our study indicates that elevated levels of MLL2 in the breast and colon cells are associated with malignancy in these tissues, in contrast to MLL involvement in haematopoietic cancer. In addition, both abnormal cellular localization of MLL2 and incomplete proteolytic processing may be associated with tumor growth/progression in breast and colonic tissues. This involvement of MLL2 in malignancy may be another example of the role of epigenetic regulators in cancer.</p

BRCA1 Regulates Follistatin Function in Ovarian Cancer and Human Ovarian Surface Epithelial Cells

Follistatin (FST), a folliculogenesis regulating protein, is found in relatively high concentrations in female ovarian tissues. FST acts as an antagonist to Activin, which is often elevated in human ovarian carcinoma, and thus may serve as a potential target for therapeutic intervention against ovarian cancer. The breast cancer susceptibility gene 1 (BRCA1) is a known tumor suppressor gene in human breast cancer; however its role in ovarian cancer is not well understood. We performed microarray analysis on human ovarian carcinoma cell line SKOV3 that stably overexpress wild-type BRCA1 and compared with the corresponding empty vector-transfected clones. We found that stable expression of BRCA1 not only stimulates FST secretion but also simultaneously inhibits Activin expression. To determine the physiological importance of this phenomenon, we further investigated the effect of cellular BRCA1 on the FST secretion in immortalized ovarian surface epithelial (IOSE) cells derived from either normal human ovaries or ovaries of an ovarian cancer patient carrying a mutation in BRCA1 gene. Knock-down of BRCA1 in normal IOSE cells demonstrates down-regulation of FST secretion along with the simultaneous up-regulation of Activin expression. Furthermore, knock-down of FST in IOSE cell lines as well as SKOV3 cell line showed significantly reduced cell proliferation and decreased cell migration when compared with the respective controls. Thus, these findings suggest a novel function for BRCA1 as a regulator of FST expression and function in human ovarian cells

Nations within a nation: variations in epidemiological transition across the states of India, 1990–2016 in the Global Burden of Disease Study

18% of the world's population lives in India, and many states of India have populations similar to those of large countries. Action to effectively improve population health in India requires availability of reliable and comprehensive state-level estimates of disease burden and risk factors over time. Such comprehensive estimates have not been available so far for all major diseases and risk factors. Thus, we aimed to estimate the disease burden and risk factors in every state of India as part of the Global Burden of Disease (GBD) Study 2016

Effect of FST knock down on cell migration.

<p>(A–F) Cell migration analysis was performed for IOSE 7576, IOSE 397 and SKOV3 cell lines that were transfected with either control siRNA or FST-siRNA. Relative fluorescence units (RFU) measured from all the migrated cells in each sample are shown in A–C, whereas, analysis of the total number cells loaded in the Boyden chamber verses total number of cells migrated towards the chemo attractant (10% FBS) in each case are shown in D–F. (G) Western blot for IOSE 7576, IOSE 397 and SKOV3 cell lines confirming knock-down of FST by FST-siRNA.</p

Western blot analysis for IOSE cells.

<p>IOSE 397 (A) and IOSE 7576 (B) cells were transiently transfected either with wtBRCA1 or BRCA1-siRNA in each case. Whole cell lysates from the attached cells were fractionated in 4–12% BT gel, and subsequently immunoblotted with the indicated antibodies. Densitometric analyses of the immunoblots shown above are given in C and D respectively.</p

Cell proliferation and cell migration assay with IOSE cells.

<p>(A) Comparative analysis of cell proliferation for IOSE 7576, IOSE 397 and IOSE 592F cell lines. (B) Western blot analysis showing FST levels for IOSE 7576, IOSE 397 and IOSE 592F cell lines. (C–D) Comparative cell migration analysis for IOSE 7576, IOSE 397 and IOSE 592F cell lines. Relative fluorescence units (RFU) was measured using all of the migrated cells to the feeder tray in each sample (C), whereas, analysis of the total number cells loaded in the Boyden chamber verses total number of cells migrated towards the chemo attractant (10% FBS) in each case is shown in (D).</p