Protein kinase C pathway is involved in the inhibition by crocetin of vascular smooth muscle cells proliferation

Abstract

Crocetin is a natural carotenoid compound isolated from Gardenia jasminoids Ellis. Our previous study showed that crocetin inhibits angiotensin II (Ang II)-induced proliferation of vascular smooth muscle cells (VSMCs). The present study investigated the involvement of the protein kinase C (PKC) pathway in the growth-inhibitory action of crocetin in VSMCs. The findings showed that PKC activity in the membrane fraction of VSMCs increased following stimulation with Ang II, which was suppressed significantly by pretreating the cells with crocetin. Inhibition of PKC activity by crocetin appeared to be associated with growth inhibition in VSMCs, because chelerythrine chloride, a specific PKC inhibitor, likewise decreased cell proliferation. PKC-a, a conventional PKC isoform, was detected in bovine aorta VSMCs by RT-PCR and western blotting analysis. Crocetin inhibited Ang II-induced membrane translocation of PKC-a, and the inhibition of crocetin on PKC activity in membrane fraction coincided with its suppression on membrane translocation of PKC-a. In addition, Ang II-induced mRNA expressions of c-fos, c-jun and c-myc were also decreased by crocetin. Taken together, the data suggest that the inhibition by crocetin of PKC activity, at least in part due to inactivation of PKC-a, and the subsequent suppression of proto-oncogene expressions might mediate its inhibitory effect on VSMCs proliferation.

Comparative Reverse Screening Approach to Identify Potential Anti-neoplastic Targets of Saffron Functional Components and Binding Mode

“…In these group GTPase HRas, Ras-related protein Rab-5A, Ras-related protein Rap-2a and RAF proto-oncogene serine/threonine-protein kinase targets are related to Ras and Raf signaling pathways. In vivo studies have demonstrated that Crocetin has played a therapeutic role in Ras and Raf signaling induced carcinoma in mice (Zhou et al, 2010). Thus our results very well correlate with the experimental evidence.…”

Quercetin improves nonalcoholic fatty liver by ameliorating inflammation, oxidative stress, and lipid metabolism in db/db mice

“…The total proteins (50 or 100 μg) were resolved on 10% SDS-PAGE gel and transferred to nitrocellulose membranes, as previous described. (Zhou, Xiang, He, & Qian, 2010a, 2010b. The membranes were blocked in Tris Buffered Saline with Tween containing 3% bovine serum albumin for 1 hr at room temperature and further incubated with special antibodies, including FXR1, TGR5, and β-actin (1:1,000) at 4°C overnight.…”

Cellular and Molecular Mechanisms in Vascular Smooth Muscle Cells by which Total Saponin Extracted from Tribulus Terrestris Protects Against Artherosclerosis

“…PKC-α, a conventional PKC isoform, has been shown to mediate VSMCs proliferation in rat, human and bovine [9,16,17]. Thus, we focused on the role of PKC-α in the suppression of TSETT on angiotensin II-induced VSMCs proliferation.…”

“…Our result exhibited that the mRNA expressions of c-fos and c-jun were increased clearly by angiotensin II and the increases were inhibited significantly by pretreatment with TSETT This result implied that the proto-oncogene mediated the suppressive effect by TSETT on the proliferation in VSMCs. In fact, previous study showed that chelerythrine chloride, a specific inhibitor of PKC, did not affect activation of ERK1/2 [9], which means that angiotensin II -induced ERK1/2 activation might be independent of PKC in VSMCs. These data suggest that the inhibition of proto-oncogene expression by TSETT attribute to the inhibitory effect on both PKC and ERK1/2.…”

“…Reactive oxygen species (ROS) as mediators of angiotensin II act on calcium signaling [5]. Subsequently, a growing body of evidence suggests that protein kinase C (PKC), extracellular signal-regulated kinase 1/2 (ERK1/2) and some immediate-early proto-oncogenes, such as c-fos and c-jun, are involved in the proliferation of VSMCs induced by angiotensin II [6,7,8,9]. …”