Nimbolide inhibits IGF-I-mediated PI3K/Akt and MAPK signalling in human breast cancer cell lines (MCF-7 and MDA-MB-231).

The insulin-like growth factor I (IGF-I) signalling pathway contributes a major role on various cancer cell proliferation, survival and cell cycle. The present study was aimed to investigate the effect of nimbolide on IGF signalling and cell cycle arrest in MCF-7 and MDA-MB-231 breast cancer cell lines. The protein expression of IGF signalling molecules and cell cycle protein levels was assessed by western blot analysis. In order to study the interaction of nimbolide on IGF-1 signalling pathway, IGF-I and phosphoinositide 3-kinase (PI3K) inhibitor (LY294002) were used to treat MCF-7 and MDA-MB-231 cells. Further, the cell cycle arrest was analysed by flow cytometry. The protein expression of IGF signalling molecules was significantly decreased in nimbolide-treated breast cancer cells. PI3K inhibitor and IGF-I with nimbolide treatment notably inhibited phosphorylated Akt. The cell cycle arrest was observed at the G0/G1 phase, and accumulation of apoptotic cells was observed in nimbolide-treated breast cancer cell lines. Nimbolide also increased the protein expression of p21 and decreased the cyclins in both the cell lines. Nimbolide decreases the proliferation of breast cancer cells by modulating the IGF signalling molecules, which could be very useful for the breast cancer treatment.

Mechanism of apoptotic induction in human breast cancer cell, MCF-7, by an analog of curcumin in comparison with curcumin--an in vitro and in silico approach.

In developing countries, survival rates for breast cancer are poor and it accounts for 22.9% of all cancers in women. Curcumin, a major constituent from turmeric, is one of the well-known chemopreventive agents. Reports have shown that curcumin induces apoptosis in breast cancer cells. We synthesized an ortho-hydroxy substituted analog of curcumin (BDMC-A) and analyzed its cytotoxicity. The BDMC-A inhibited MCF-7 at a dose equivalent to that of curcumin (30 µM). The present study was aimed at delineating the apoptotic mechanism of BDMC-A in comparison to that of curcumin. In our study, BDMC-A exerted more potent effect on the modulation of selective apoptotic markers (intrinsic pathway: p53, Bcl-2, Bax, cyt c, Apaf-1, caspase-9, 3, PARP; extrinsic pathway: FasL, caspase 8) compared to curcumin. mRNA expression studies for Bcl2/Bax also supported the increased efficacy of BDMC-A. An in silico molecular docking study with PI3K revealed that the docking of BDMC-A was more potent compared to curcumin. Increased apoptotic induction by BDMC-A compared to curcumin was also demonstrated by Annexin V, Rh123 (ΔΨm), PI, Hoechst 33258, AO/EB fluorescent staining studies which showed characteristic apoptotic features like nuclear fragmentation and chromatin condensation. Moreover, BDMC-A treated cells effectively induced apoptosis through ROS intermediates compared to curcumin, as measured by 2'-7'-Dichlorodihydrofluorescein diacetate (DCFH-DA). Hence our overall results showed that BDMC-A induced apoptosis more effectively compared to curcumin and the activity can be attributed to the presence of hydroxyl group in the ortho position in its structure. Further researches are going on to delineate its molecular targets to evaluate its effect as a potent anticancer agent.

Expression of matrix metalloproteinases in human breast cancer tissues.

BACKGROUND: Breast cancer is the most common cancer affecting women in the world today. Matrix metalloproteinases (MMPs) are a family of endopeptidases that can degrade extracellular matrix proteins and promote cell invasion and metastasis. MMPs are differentially expressed and their expressions are often associated with a poor prognosis for patients. OBJECTIVE: The aim of this study is to investigate and compare the expression of MMPs in different grades of human breast cancer tissues with normal breast tissues. PATIENTS AND METHODS: We collected 39 breast cancer samples (24 grade II and 15 grade III) along with 16 normal breast tissues from outside the tumor margin during cancer removal surgery. The samples were analysed for the expression of all known MMPs using real-time quantitative PCR. RESULTS: The results indicate that mRNA expressions of MMP-1, -9,-11,-15,-24 and -25 were upregulated in breast cancer tissues when compared to normal breast tissues. But, the mRNA expressions of MMP-10 and MMP-19 were downregulated in cancer tissue. In membrane associated MMPs like MMP-15 and MMP-24 we found a grade dependent increase of their mRNA expression. CONCLUSION: Our studies demonstrate that MMPs are differentially regulated in breast cancer tissues and they might play various roles in tumor invasion, metastasis and angiogenesis. Thus, MMPs are of immense value to be studied as diagnostic markers and drug target.