sinomenine and Neoplasms

Sinomenine (SIN) is a bioactive alkaloid compound extracted from a Chinese medicinal plant Sinomenium acutum. It is a multitarget antitumor natural substance. Various mechanisms have been proposed for the antitumor effects of SIN, such as direct cytotoxicity, induction of apoptosis, sensitization attenuating radiotherapy and chemotherapy, reversal of drug resistance, resistance to distant metastasis, and antiangiogenesis. SIN can be used as a tumor cell killer and an adjuvant to radiotherapy and chemotherapy. However, recent studies are mostly limited to the basic experimental stage; no systematic clinical studies have yet been reported. Therefore, this paper aimed to review the mechanism underlying the antitumor effects of SIN by consulting relevant domestic and foreign studies and to provide a relevant reference for further development, use, and exploration of SIN.

Topics: Alkaloids; Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Chemotherapy, Adjuvant; Humans; Morphinans; Neoplasms; Plants, Medicinal; Radiotherapy, Adjuvant; Signal Transduction

The oxidative pentose phosphate pathway (PPP) contributes to tumour growth, but the precise contribution of 6-phosphogluconate dehydrogenase (6PGD), the third enzyme in this pathway, to tumorigenesis remains unclear. We found that suppression of 6PGD decreased lipogenesis and RNA biosynthesis and elevated ROS levels in cancer cells, attenuating cell proliferation and tumour growth. 6PGD-mediated production of ribulose-5-phosphate (Ru-5-P) inhibits AMPK activation by disrupting the active LKB1 complex, thereby activating acetyl-CoA carboxylase 1 and lipogenesis. Ru-5-P and NADPH are thought to be precursors in RNA biosynthesis and lipogenesis, respectively; thus, our findings provide an additional link between the oxidative PPP and lipogenesis through Ru-5-P-dependent inhibition of LKB1-AMPK signalling. Moreover, we identified and developed 6PGD inhibitors, physcion and its derivative S3, that effectively inhibited 6PGD, cancer cell proliferation and tumour growth in nude mice xenografts without obvious toxicity, suggesting that 6PGD could be an anticancer target.

Topics: AMP-Activated Protein Kinase Kinases; AMP-Activated Protein Kinases; Humans; Lipogenesis; Neoplasms; Oxidative Stress; Pentose Phosphate Pathway; Phosphogluconate Dehydrogenase; Protein Serine-Threonine Kinases; Ribulosephosphates; Signal Transduction