Recently, we reported that Rhus coriaria exhibits anticancer activities by promoting cell cycle arrest and autophagic cell death of the metastatic triple negative MDA-MB-231 breast cancer cells. Here, we investigated the effect of Rhus coriaria on the migration, invasion, metastasis and tumor growth of TNBC cells. Our current study revealed that non-cytotoxic concentrations of Rhus coriaria significantly inhibited migration and invasion, blocked adhesion to fibronectin and downregulated MMP-9 and prostaglandin E2 (PgE2). Not only did Rhus coriaria decrease their adhesion to HUVECs and to lung microvascular endothelial (HMVEC-L) cells, but it also inhibited the transendothelial migration of MDA-MB-231 cells through TNF-α-activated HUVECs. Furthermore, we found that Rhus coriaria inhibited angiogenesis, reduced VEGF production in both MDA-MB-231 and HUVECs and downregulated the inflammatory cytokines TNF-α, IL-6 and IL-8. The underlying mechanism for Rhus coriaria effects appears to be through inhibiting NFκB, STAT3 and nitric oxide (NO) pathways. Most importantly, by using chick embryo tumor growth assay, we showed that Rhus coriaria suppressed tumor growth and metastasis in vivo. The results described in the present study identify Rhus coriaria as a promising chemopreventive and therapeutic candidate that modulate triple negative breast cancer growth and metastasis.

Here, we investigated the anticancer effect of Rhus coriaria on three breast cancer cell lines. We demonstrated that Rhus coriaria ethanolic extract (RCE) inhibits the proliferation of these cell lines in a time- and concentration-dependent manner. RCE induced senescence and cell cycle arrest at G1 phase. These changes were concomitant with upregulation of p21, downregulation of cyclin D1, p27, PCNA, c-myc, phospho-RB and expression of senescence-associated β-galactosidase activity. No proliferative recovery was detected after RCE removal. Annexin V staining and PARP cleavage analysis revealed a minimal induction of apoptosis in MDA-MB-231 cells. Electron microscopy revealed the presence of autophagic vacuoles in RCE-treated cells. Interestingly, blocking autophagy by 3-methyladenine (3-MA) or chloroquine (CQ) reduced RCE-induced cell death and senescence. RCE was also found to activate p38 and ERK1/2 signaling pathways which coincided with induction of autophagy. Furthermore, we found that while both autophagy inhibitors abolished p38 phosphorylation, only CQ led to significant decrease in pERK1/2. Finally, RCE induced DNA damage and reduced mutant p53, two events that preceded autophagy. Our findings provide strong evidence that R. coriaria possesses strong anti-breast cancer activity through induction of senescence and autophagic cell death, making it a promising alternative or adjunct therapeutic candidate against breast cancer.

Colorectal cancer is the fourth leading cause of cancer-related deaths worldwide. Here, we investigated the anticancer effect of Rhus coriaria extract (RCE) on HT-29 and Caco-2 human colorectal cancer cells. We found that RCE significantly inhibited the viability and colony growth of colon cancer cells. Moreover, RCE induced Beclin-1-independent autophagy and subsequent caspase-7-dependent apoptosis. Blocking of autophagy by chloroquine significantly reduced RCE-induced cell death, while blocking of apoptosis had no effect on RCE-induced cell death. Mechanistically, RCE inactivated the AKT/mTOR pathway by promoting the proteasome-dependent degradation of both proteins. Strikingly, we also found that RCE targeted Beclin-1, p53 and procaspase-3 to degradation. Proteasome inhibition by MG-132 not only restored these proteins to level comparable to control cells, but also reduced RCE-induced cell death and blocked the activation of autophagy and apoptosis. The proteasomal degradation of mTOR, which occurred only 3 hours post-RCE treatment was concomitant with an overall increase in the level of ubiquitinated proteins and translated stimulation of proteolysis by the proteasome. Our findings demonstrate that Rhus coriaria possesses strong anti-colon cancer activity through stimulation of proteolysis as well as induction of autophagic and apoptotic cell death, making it a potential and valuable source of novel therapeutic cancer drug.

Effects of curcumin, a major ingredient of turmeric, were tested on the function of the -subunit of the human nicotinic acetylcholine (-nACh) receptor expressed in oocytes and on nociception in mouse models of tonic and visceral pain. Curcumin caused a significant potentiation of currents induced by acetylcholine (ACh; 100M) with an EC value of 0.2 M. The effect of curcumin was not dependent on the activation of G-proteins and protein kinases and did not involve Ca-dependent Cl channels expressed endogenously in oocytes. Importantly, the extent of curcumin potentiation was enhanced significantly by decreasing ACh concentrations. Curcumin did not alter specific binding of [I]-bungarotoxin. In addition, curcumin attenuated nociceptive behavior in both tonic and visceral pain models without affecting motor and locomotor activity and without producing tolerance. Pharmacological and genetic approaches revealed that the antinociceptive effect of curcumin was mediated by -nACh receptors. Curcumin potentiated the antinociceptive effects of the-nACh receptor agonist -(3R)-1-azabicyclo[2.2.2]oct-3-yl-4-chlorobenzamide (PNU282987). Collectively, our results indicate that curcumin is a positive allosteric modulator of-nACh receptor and reverses nociception in mouse models of tonic and visceral pain.