Effect of Doxycycline on Intrinsic Apoptosis of Myeloma Cell Line H929 and Its Mechanism / 中国实验血液学杂志

OBJECTIVE@#To investigate the mechanism of the in vitro toxicity of doxycycline to myeloma cell line H929 and also the possible pathway involved its toxicity.@*METHODS@#Myeloma cell line H929 was treated with DOX, MEK inhibitor U0126 or RAS agonist ML-098, either alone or in combination. Then, the expression of p-MEK, caspase-3, caspase-9 and c-Jun in H929 were used to detected by Western blot; the cells proliferation and apoptosis were detected by CCK-8 assay and flow cytometry, respectively.@*RESULTS@#DOX significantly increased the levels of cleaved caspase-3 and caspase-9, and down-regulated the level of p-MEK in H929 (P<0.05). MEK antagonist U0126 significantly increased the levels of cleaved caspase-3 and caspase-9, and down-regulated the level of p-MEK (P<0.05). After Dox combined with ML-098 treatment of H929 cells, the apoptosis rate of H929 cells was lower than that of DOX alone treatment group(P<0.05). Compared with DOX alone treatment group, the expressions of p-MEK and p-ERK1/2 in DOX+ML-098 combined treatment group were increased, and the levels of cleaved caspase-3,9 in H929 cells were decreased (P<0.05). The levels of c-Jun mRNA and protein increased in H929 when treated by DOX alone (P<0.05).@*CONCLUSION@#DOX can induce apoptosis of H929 via intrinsic apoptosis pathway, and MEK/ERK pathway and c-Jun possibly play a role in this process.

Polydatin protects H9c2 cells from hypoxia-induced injury via up-regulating long non-coding RNA DGCR5

Polydatin (PD), a monocrystalline polyphenolic drug mainly found in the roots of Polygonum cuspidatum, has various pharmacological activities. Long non-coding RNAs (lncRNA) DiGeorge syndrome critical region gene 5 (DGCR5) was found to participate in the suppression of multiple cancers. Here, we proposed to study the effect of PD on myocardial infarction (MI) by inducing DGCR5. CCK-8 assay was performed to detect the viability of H9c2 cells. Flow cytometry was utilized to test apoptosis of H9c2 cells. These results determined the optimal concentration and effect time of hypoxia as well as PD. Si-DGCR5 was transfected into cells and the expression level was determined by qRT-PCR. Western blot was utilized to evaluate the expression of apoptosis-related proteins, Bcl-2, Bax, and cleaved-caspase-3, as well as autophagy-associated proteins including Beclin-1, p62, and LC3-II/LC3-I. As a result, PD efficiently attenuated hypoxia-induced apoptosis and autophagy in H9c2 cells. The expression of DGCR5 was down-regulated by hypoxia and up-regulated by PD. Besides, knocking-down the expression of DGCR5 inhibited the protection of PD in H9c2 cells. In addition, PD up-regulated the accumulation of DGCR5, DGCR5 decreased the expression of Bcl-2 and p62, raised the expression of Bax and cleaved-caspase-3, and the proportion of LC3-II/LC3-I. PD stimulated the PI3K/AKT/mTOR and MEK/ERK signaling pathways via up-regulating the expression of DGCR5. Our data demonstrated that PD reduced cell apoptosis and autophagy induced by hypoxia in cardiomyocytes. Moreover, PD activated PI3K/AKT/mTOR and MEK/ERK signaling pathways by up-regulating the expression of DGCR5.

Screening of monomers from traditional Chinese medicine for specifically inhibiting brafV600E CT26 cells / 中国药理学通报

Aim: To screen BRAFV600E CT26 cell inhibitors from monomers of traditional Chinese medicine (TCM). Methods CT26 cell line was constructed with lentivirus plasmid to stably express BRAFV6C0E. The proliferation, migration and expression of related proteins in MEK/ERK signaling pathway were detected. The monomers of TCM were detected for biological activities as potential BRAF inhibitors by Discovery Studio 4. 0, and further evaluated by MTT assay. Results: The proliferation and migration of BRAFV6C0E CT26 cells were obviously strengthened compared with wild type control. The expressions of proteins in MEK/ ERK pathway were also activated in BRAFV6C0E CT26 cells. Compared with wild type control, Aloin, Angoroside C and Cyasterone exhibited the potent effect against BRAFV600E in CT26 cells (P <0. 05), and could down-regulate the expression of BRAFV600E. Conclusion: Aloin, Angoroside C, Cyasterone might be the potent inhibitors against BRAF for colon treatment.

Advances in research on the modulation of autophagy by Ras/Raf/MEK/ERK signaling pathway / 中国药科大学学报

@#Autophagy is a conserved self-defense mechanism of organism, degrading the necrotic organelles and excess protein into small molecules for recycling. Autophagy plays a role in both physiological and pathological condition, influencing the expression of intracellular substance through multiple signaling pathways. Although it has been demonstrated that Ras/Raf/MEK/ERK signaling pathway was not only extensively involved in the regulation of cell growth, proliferation, differentiation and apoptosis, but was also implicated in autophagy and autophagic cell death, though its detailed mechanisms involved in regulation of autophagy has not been fully elucidated yet. This review focused on the advances of autophagy induced by Ras/Raf/MEK/ERK signaling pathway, to better understand the role of Ras/Raf/MEK/ERK signaling pathway in regulation of autophagy.

Advances in the targeted therapy of cancer:multi-targeted Raf kinase inhibitor / 中国癌症杂志

Advances in the understanding of cancer at the molecular level have led to much progress in the development of anti-cancer agents. Among the newly invented medications for targeted cancer therapy, protein kinase inhibitors target intracellular molecules crucial in signaling pathways for cancer cell survival, proliferation, and disease progression. The Raf serine/threonine kinases are pivotal molecules within the Raf/mitogen extracellular kinase (MEK)/extracellular signal-related kinase (ERK) signaling pathway. The exact function of Raf in normal human cells is not yet understood; however, preclinical and clinical researches have shown that over expression of Raf gene or overreaction of Raf kinase isoforms have critical roles in many types of solid tumors, including renal cell carcinoma, hepatocellular carcinoma, melanoma, and non-small cell lung cancer (NSCLC). Sorafenib is the first oral, multi-kinase inhibitor that targets the Raf kinases. It also has a broad spectrum activity against other receptor tyrosine kinases associated with vascular endothelial growth factor receptors and platelet-derived growth factor receptors. Sorafenib was recently approved by FDA for use in advanced renal cell cancer, and is currently undergoing active investigation in the treatment of other types of malignancies, such as melanoma, liver cancer, prostate cancer, and NSCLC. In this review, we will illustrate the role of Raf in both normal and malignant cells, the mechanism of sorafenib in the treatment of renal cell carcinoma, as well as clinical data that support its use and further investigation in advanced renal cell carcinoma, melanoma, and other tumor types.