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Acquisition of cisplatin resistance is the common and critical limitation for hepatocellular carcinoma (HCC) therapy. Our study was aimed to determine whether there were conditions under which the addition of imperatorin would reverse the resistance of HCC cells to cisplatin-based therapy. In this study, we found that addition of imperatorin significantly enhanced the cytotoxicity of cisplatin to HCC cells. Since the Mcl-1 was overexpressed in HCC cell lines (HepG2, HepG3B, PLC, Huh7) compared with normal liver cell line (L-O2), we found that the Mcl-1 expression was downregulated by imperatorin but not influenced by cisplatin in HCC cells. In addition, our results showed the combination of imperatorin and cisplatin induced apoptosis and ∆Ψm collapse more significantly compared with treatment of imperatorin or cisplatin alone. Furthermore, the imperatorin-induced sensitization for cisplatin-cytotoxicity to HCC cells was abolished by the transfection of Mcl-1 expression plasmid. Finally, we found that the addition of imperatorin significantly reversed the resistance to cisplatin in cisplatin-resistant HCC cells, which was Mcl-1 dependent. In summary, our study revealed that combination with imperatorin could enhance the antitumor activity of cisplatin via targeting Mcl-1 and reverse the resistance to cisplatin in HCC.

BaP promotes Ang II-induced AAA formation in mice via elevating infiltration of macrophages, activating nuclear factor-κB, upregulating the expression of MMP-2, MMP-9, and MMP-12, and increasing the apoptosis of vascular muscle cells in its synergistic effect with Ang II in aortic wall.

Inorganic polyphosphate (polyP) is an ancient energy metabolite and phosphate store that occurs ubiquitously in all organisms. The vacuolar transporter chaperone (VTC) complex integrates cytosolic polyP synthesis from ATP and polyP membrane translocation into the vacuolar lumen. In yeast and in other eukaryotes, polyP synthesis is regulated by inositol pyrophosphate (PP-InsP) nutrient messengers, directly sensed by the VTC complex. Here, we report the cryo-electron microscopy structure of signal-activated VTC complex at 3.0 Å resolution. Baker’s yeast VTC subunits Vtc1, Vtc3, and Vtc4 assemble into a 3:1:1 complex. Fifteen trans-membrane helices form a novel membrane channel enabling the transport of newly synthesized polyP into the vacuolar lumen. PP-InsP binding orients the catalytic polymerase domain at the entrance of the trans-membrane channel, both activating the enzyme and coupling polyP synthesis and membrane translocation. Together with biochemical and cellular studies, our work provides mechanistic insights into the biogenesis of an ancient energy metabolite.

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