Modulatory effects of silibinin in various cell signaling pathways against liver disorders and cancer – A comprehensive review

Silybin Against Liver Ischemia-Reperfusion Injury: Something Old, Something New…

Ischemia reperfusion injury (IRI) is a life threatening condition that may develop after elective liver surgery or liver transplantation. Numerous surgical and pharmacological approaches have shown varying degrees of protection against liver IRI. A group of protective compounds are the flavonoids but their intestinal absorbtion and bioavailability are low and impredictible. In this issue Tsaroucha et al. reports significantly decreased hepatocellular injury, Fas/FasL expression and inhibited HMGB1 release in rats receiving a hydrosoluble, lyophilized complex of SLB and hydroxypropyl-β-cyclodextrin (SLB-HP-β-CD) intravenously.

Silibinin suppresses bladder cancer through down-regulation of actin cytoskeleton and PI3K/Akt signaling pathways

Silibinin is the major active constituent of silymarin, an extract of milk thistle seeds. Silibinin has been shown to have significant anti-cancer effects in a variety of malignancies. However, the molecular mechanisms of silibinin action in bladder cancer have not been studied extensively. In the present study, we found that silibinin (10 μM) significantly suppressed proliferation, migration, invasion and induced apoptosis of T24 and UM-UC-3 human bladder cancer cells. Silibinin down-regulated the actin cytoskeleton and phosphatidylinositide 3-kinase (PI3K)/Akt signaling pathways in these cancer cell lines. These pathways were found to crosstalk through RAS cascades. We found that silibinin suppressed levels of trimethylated histone H3 lysine 4 and acetylated H3 at the KRAS promoter. Furthermore, silibinin targets long non-coding RNA: HOTAIR and ZFAS1, which are known to play roles as oncogenic factors in various cancers. This study shows that silibinin exerts anti-cancer effects through down-regulation of actin cytoskeleton and PI3K/Akt pathways and thus suppresses bladder cancer growth and progression.

Design and discovery of silybin analogues as antiproliferative compounds using a ring disjunctive - Based, natural product lead optimization approach

The present study reports the synthesis and anticancer activity evaluation of twelve novel silybin analogues designed using a ring disjunctive-based natural product lead (RDNPL) optimization approach. All twelve compounds were tested against a panel of cancer cells (i.e. breast, prostate, pancreatic, and ovarian) and compared with normal cells. While all of the compounds had significantly greater efficacy than silybin, derivative 15k was found to be highly potent (IC₅₀ < 1 μM) and selective against ovarian cancer cell lines, as well as other cancer cell lines, compared to normal cells. Preliminary mechanistic studies indicated that the antiproliferative efficacy of 15k was mediated by its induction of apoptosis, loss of mitochondrial membrane potential and cell cycle arrest at the sub-G1 phase. Furthermore, 15k inhibited cellular microtubules dynamic and assembly by binding to tubulin and inhibiting its expression and function. Overall, the results of the study establish 15k as a novel tubulin inhibitor with significant activity against ovarian cancer cells.