Thymoquinone Inhibits Proliferation and Migration of MDA-MB-231 Triple Negative Breast Cancer Cells by Suppressing Autophagy, Beclin-1 and LC3.

BACKGROUND: Triple Negative Breast Cancer (TNBC) is an aggressive and highly heterogeneous subtype of breast cancer associated with poor prognosis. A better understanding of the biology of this complex cancer is needed to develop novel therapeutic strategies for the improvement of patient survival. We have previously demonstrated that Thymoquinone (TQ), the major phenolic compound found in Nigella sativa, induces anti-proliferative and anti-metastatic effects and inhibits in vivo tumor growth in orthotopic TNBC models in mice. Also, we have previously shown that Beclin-1 and LC3 autophagy genes contributes to TNBC cell proliferation, migration and invasion, suggesting that Beclin-1 and LC3 genes provide proto-oncogenic effects in TNBC. However, the role of Beclin-1 and LC3 in mediating TQ-induced anti-tumor effects in TNBC is not known. OBJECTIVE: To investigate the effects of TQ on the major autophagy mediators, Beclin-1 and LC3 expression, as well as autophagic activity in TNBC cells. METHODS: Cell proliferation, colony formation, migration and autophagy activity were evaluated using MTS cell viability, colony formation assay, wound healing and acridine orange staining assays, respectively. Western blotting and RT-PCR assays were used to investigate LC3 and Beclin-1 protein and gene expressions, respectively, in MDA-MB-231 TNBC cells in response to TQ treatments. RESULTS: TQ treatment significantly inhibited cell proliferation, colony formation, migration and autophagic activity of MDA-MB-231 cells and suppressed LC3 and Beclin-1 expressions. Furthermore, TQ treatment led to the inhibition of Integrin-ß1, VEGF, MMP-2 and MMP-9 in TNBC cells. CONCLUSION: TQ inhibits autophagic activity and expression of Beclin-1 and LC3 in TNBC cells and suppresses pathways related to cell migration/invasion and angiogenesis, including Integrin-ß1, VEGF, MMP-2 and MMP- 9, suggesting that TQ may be used to control autophagic activity and oncogenic signaling in TNBC.

Immunohistochemical expression profiles of BRAF (V600E/VE1) in serrated colon polyps in Turkish population.

BACKGROUND AND AIM: Colon carcinoma, as one of the most common cancers, has been investigated for genetic alterations. Besides well-known adenoma-carcinoma sequence, it is recently found that BRAF mutation had an important role particularly in early stages of adenocarcinomas with serrated features. There are no any studies concerning immunohistochemical expression status of BRAF V600E (VE1) antibody in serrated polyps in the Turkish population. The objective of this study is to observe the immunohistochemical staining of BRAF V600E (VE1) antibody in colon polyps in the Turkish population and investigate the frequency of presence of mutated BRAF proteins indicating malignant potential. MATERIALS AND METHODS: 59 cases of serrated polyps (27 cases of hyperplastic polyps, 18 cases of sessile serrated adenoma/polyps and 14 cases of traditional serrated adenomas) and 10 tubular adenomas, and 10 samples of normal colonic mucosa were immunohistochemically evaluated for the presence of BRAF V600E mutated proteins with the VE1 antibody. Results were statistically compared. RESULTS: All SSA/Ps; 92.8% of TSAs; 37% of HPs were stained positively. Of the 27 hyperplastic polyps, all GCHPs were negative but 10 of 12 MVHPs (83.3%) were weakly positive with the VE1 antibody. Cases in control groups and tubular adenomas didn't show any cytoplasmic staining. CONCLUSION: Serrated adenoma/polyps have been gaining much more importance because of their malignant potential. Their frequency is also relatively high in the Turkish population and they should be carefully handled. Detection of BRAF V600E status can be easily achieved immunohistochemically by VE1 antibody. It is easily applicable and reproducible method and it might be helpful in identifying serrated lesions of the colon in addition to morphological features.