Solanine induces ferroptosis in colorectal cancer cells through ALOX12B/ADCY4 molecular axis.

OBJECTIVES: Colorectal cancer (CRC) is the fourth most commonly diagnosed cancer worldwide. Solanine is a phytochemical extracted from traditional Chinese medicine with widely reported anticancer effects. Here, we investigated the potential role of solanine in regulating ferroptosis in CRC cells and scrutinized the molecular mechanism. METHODS: Cell growth and cytotoxicity were examined using CCK-8 proliferation assay and lactate dehydrogenase assay. Oxidative stress was determined by measuring glutathione (GSH), malondialdehyde, and reactive oxygen species (ROS) levels. Subcellular changes in mitochondria were examined by transmission electron microscopy. Gene and protein expression levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Protein-protein interaction was determined by co-immunoprecipitation. KEY FINDINGS: Solanine arrested cell proliferation in CRC cells and induced typical ferroptotic changes. Solanine treatment promoted ROS production, lipid peroxidation, and cell membrane disruption, while the cellular level of antioxidant GSH was reduced upon solanine treatment. ALOX12B was identified as a molecular mediator of solanine to promote ferroptosis. Solanine treatment upregulated ALOX12B levels and silencing ALOX12B could suppress solanine-induced ferroptosis. Further, ADCY4 was found to physically associate with ALOX12B and maintain ALOX12B protein stability. Silencing ADCY4 destabilized ALOX12B and attenuated solanine-induced ferroptosis. CONCLUSIONS: Our data demonstrated the ferroptosis-inducing effect of solanine in CRC cells, and revealed ALOX12B/ADCY4 molecular axis as the ferroptosis mediator of solanine. Solanine may synergize with existing ferroptosis inducer as an anticancer strategy in CRC, which warrants further validation in animal experiments.

Protection effect of polyols on Rhizopus chinensis lipase counteracting the deactivation from high pressure and high temperature treatment.

The influence of polyols on Rhizopus chinensis lipase (RCL) was investigated under high pressure. The poor stability of RCL was observed at 500 MPa at 60 °C without polyols which protected RCL against the loss of activity. The lipase is more stable in phosphate buffer than in tris buffer despite the protection of polyols. The activity was maintained 63% by the sorbitol of 2 mol/L in Tris-HCl buffer but 73% in phosphate buffer after the treatment at 500 MPa and 60 °C for 25 min. The same protective effects could be observed at 1 mol/L of sorbitol, erythritol, xylitol, and mannitol. However, further increase of hydroxyl group number could not significantly improve the enzyme stability. The protection of polyols on RCL appears to depend on both of the polyol nature and the hydroxyl group number. Together with fluorescence spectra, circular dichroism spectra indicated that the chaotic conformation of RCL under high pressure became more ordered with 1 mol/L sorbitol. The results showed that sorbitol effectively stabilized the lipase conformation including the hydrophobic core under extreme conditions. It might be attributed to the interaction of polyols with RCL surface to modify intra-/intermolecular hydrogen bonds, maintaining the hydrophobic interactions within RCL.