Cholesterol suppresses GOLM1-dependent selective autophagy of RTKs in hepatocellular carcinoma.

Aberrant activation of receptor tyrosine kinases (RTKs) and the subsequent metabolic reprogramming play critical roles in cancer progression. Our previous study has shown that Golgi membrane protein 1 (GOLM1) promotes hepatocellular carcinoma (HCC) metastasis by enhancing the recycling of RTKs. However, how this RTK recycling process is regulated and coupled with RTK degradation remains poorly defined. Here, we demonstrate that cholesterol suppresses the autophagic degradation of RTKs in a GOLM1-dependent manner. Further mechanistic studies reveal that GOLM1 mediates the selective autophagy of RTKs by interacting with LC3 through an LC3-interacting region (LIR), which is regulated by a cholesterol-mTORC1 axis. Lowering cholesterol by statins improves the efficacy of multiple tyrosine kinase inhibitors (TKIs) in vivo. Our findings indicate that cholesterol serves as a signal to switch GOLM1-RTK degradation to GOLM1-RTK recycling and suggest that lowering cholesterol by statin may be a promising combination strategy to improve the TKI efficiency in HCC.

[Research progress in mechanism of berberine's antitumor action].

Malignant tumor, an important factor threatening human life and health, brings huge economic burden to patients. At present, chemoradiotherapy is still the main treatment method for tumor diseases, but there are also great side effects when it plays a therapeutic role. Traditional Chinese medicine in the prevention and treatment of tumor diseases has many advantages such as few side effects, improving the physiological state of patients, and slowing down the side effects of radiotherapy and chemotherapy. Berberine is an effective component of rhizoma coptidis, with a very good antitumor effect. It can inhibit tumor cell proliferation, promote tumor cell apoptosis, inhibit tumor metastasis and angiogenesis, regulate tumor autophagy, reverse multi-drug resistance of tumor, regulate the body immunity, and affect tumor metabolic reprogramming to play its role. Compared with chemical preparations, berberine has a wide range of sources, with high safety and easy access, and has great potential in the prevention and treatment of malignant tumors. In this article, we would mainly review the research progress on the antitumor mechanism of berberine in recent years.

Effects of different cryoprotectants and cryopreservation protocols on the development of 2-4 cell mouse embryos.

This study evaluated the effects of different cryoprotectants and cryopreservation protocols on the development of in vivo fertilized 2-4 cell mouse embryos. Mouse embryos were cryopreserved by using propylene glycerol (PG), ethylene glycerol (EG), dimethyl sulfoxide (DMSO) or glycerol (G) as cryoprotectant with slow-freezing or Vit-Master vitrification protocol. After thawing, the survival rate, blastocyst formation rate and blastocyst hatching rate of the embryos were compared. When mouse embryos were cryopreserved by the slow-freezing, survival rate, blastocyst formation rate and blastocyst hatching rate of the embryos with PG were significantly higher than those of DMSO and G (P < 0.05, respectively), but there is no significantly difference among those of DMSO, G and EG(p > 0.05), and between PG and EG. When mouse embryos were cryopreserved by Vit-Master vitrification, survival rate, blastocyst formation rate and blastocyst hatching rate of the embryos with EG were significantly higher than those of PG, DMSO and G (P < 0.05). There were no significant differences among those of PG, DMSO and G (p > 0.05). In conclusion, PG was the optimal cryoprotectant for the cryopreservation of 2-4 cell mouse embryos by slow-freezing protocol. EG was the optimal cryoprotectant for the cryopresevation of 2-4 cell mouse embryos by Vit-Master vitrification protocol, which may be commonly used in clinical and laboratory practice.

Effects of removal of necrotic blastomeres from human cryopreserved embryos on pregnancy outcome.

This study assessed whether the implantation potential of embryos that were partially damaged after freezing and thawing can be improved by removal of necrotic blastomeres. We retrospectively analyzed the pregnancy rate and implantation rate of 170 human frozen embryo transfer cycles. Laser-assisted hatching and micromanipulation were performed to remove the necrotic blastomeres. A higher clinical pregnancy rate (22.22%) and embryo implantation rate (10.17%) were observed when transferred embryos comprised fully intact and partially damaged embryos compared with partially damaged embryos alone (5.88% and 2.82%, respectively). When transferred embryos were fully intact and partially damaged embryos, removal of necrotic blastomeres from partially damaged embryos significantly increased the clinical pregnancy rate (43.90% versus 24.00%, P<0.05) and the implantation rate (19.44% versus 10.29%, P<0.05). The results indicated that the implantation potential of partially damaged cryopreserved embryos can be improved by removal of necrotic blastomeres with laser-assisted hatching and micromanipulation.

Expression, purification and anti-tumor activity of curcin.

Curcin, purified from the seeds of Jatropha curcas, can be used as a cell-killing agent. Understanding the anti-tumor activity of the recombinant protein of curcin is important for its application in clinical medicine. The segment encoding the mature protein of curcin was inserted into Escherichia coli strain M15, and the recombinant strain was induced to express by isopropyl-beta-D-thiogalactopyranoside at a concentration of 0.5 mM. The recombinant protein was expressed in the form of inclusion bodies and purified by Ni-NTA affinity chromatography. The target protein was incubated with the tumor cells at different concentrations for different times and the results demonstrated that the target protein could inhibit the growth of tumor cells (NCL-H446, SGC-7901 and S180) at 5 microg/ml.

Effects of removal of necrotic blastomeres from mouse cryopreserved embryos on blastocyst formation and hatching.

To evaluate whether the developmental potential of embryos that were partially damaged after freezing and thawing can be improved by removal of necrotic blastomeres. Eight-cell mouse embryos were cryopreserved using 1,2-propanediol and sucrose as cryoprotectant with slow cooling procedure. After thawing, blastocyst formation and hatching of fully intact embryos were compared between no treatment and with laser-assisted hatching. For partially intact embryos, the effects of removal of necrotic blastomeres with micromanipulation were evaluated. Laser-assisted hatching of mouse cryopreserved fully intact embryos significantly increased blastocyst hatching (63.4% versus 48.3%, P<0.05), but had little effect on blastocyst formation (72.0% versus 70.1%, P>0.05). The removal of necrotic blastomeres from partially damaged mouse cryopreserved embryos with micromanipulation significantly increased blastocyst formation (52.9% versus 32.0%, P<0.05) and blastocyst hatching (41.2% versus 22.0%, P>0.05) compared with the control group. The developmental potential of partially damaged cryopreserved embryos can be improved by removal of necrotic blastomeres with micromanipulation.