Targeting metabolic vulnerability in mitochondria conquers MEK inhibitor resistance in KRAS-mutant lung cancer

MEK is a canonical effector of mutant KRAS; however, MEK inhibitors fail to yield satisfactory clinical outcomes in KRAS-mutant cancers. Here, we identified mitochondrial oxidative phosphorylation (OXPHOS) induction as a profound metabolic alteration to confer KRAS-mutant non-small cell lung cancer (NSCLC) resistance to the clinical MEK inhibitor trametinib. Metabolic flux analysis demonstrated that pyruvate metabolism and fatty acid oxidation were markedly enhanced and coordinately powered the OXPHOS system in resistant cells after trametinib treatment, satisfying their energy demand and protecting them from apoptosis. As molecular events in this process, the pyruvate dehydrogenase complex (PDHc) and carnitine palmitoyl transferase IA (CPTIA), two rate-limiting enzymes that control the metabolic flux of pyruvate and palmitic acid to mitochondrial respiration were activated through phosphorylation and transcriptional regulation. Importantly, the co-administration of trametinib and IACS-010759, a clinical mitochondrial complex I inhibitor that blocks OXPHOS, significantly impeded tumor growth and prolonged mouse survival. Overall, our findings reveal that MEK inhibitor therapy creates a metabolic vulnerability in the mitochondria and further develop an effective combinatorial strategy to circumvent MEK inhibitors resistance in KRAS-driven NSCLC.

Research progress on the biological activity of pyrrole 1,2-α indole alkaloids / 中国基层医药

Pyrrole [1,2-α] indole is a novel fused heterocyclic skeleton, which is also the basic structural unit and synthetic intermediate of many natural active products and drugs. Pyrrole [1,2-α] indole heterocyclic derivatives have attracted much attention in organic synthesis and medicinal chemistry because of their extensive and marked biological activities. Plant extracts have always been an important source of active compounds. At present, the alkaloids based on the pyrrole [1,2-α] indole heterocyclic structure discovered and isolated from plant extracts include isatisine, isoborreverine, flinderoles, polyavolensin and yuremamine. This paper reviews the research progress on the biological activity of pyrrole [1,2-α] indole heterocyclic derivatives and has found that pyrrole [1,2-α] indole heterocyclic derivatives have a good development prospect in screening active compounds and developing candidate drugs.

Research status and progress of acute myeloid leukemia stem cells / 中国基层医药

Acute myeloid leukemia is a clonal malignant proliferative disease of myeloid blasts of the hematopoietic system. The leukemia cell population is composed of cells of different stages. Acute myeloid leukemia stem cells are the cells that may cause diseases in immunodeficient animals and can regenerate themselves through continuous transplantation, which causes leukemia. Since more than 96% of leukemia stem cells are in the G0 stage, they may escape the effects of chemical drug stabbing, leading to drug resistance and recurrence of leukemia. Therefore, the key to the treatment of acute myeloid leukemia has always been how to remove leukemia stem cells without damaging hematopoietic stem cells. This review paper addresses the new developments in the immunophenotype of leukemia stem cells and leukemia stem cells-targeting therapy for acute myeloid leukemia.

Current status of glioma therapy / 中国基层医药

Gliomas are a group of refractory heterogeneous diseases. Gliomas even at the same pathological type and grade exhibit different outcomes after treatment. Therefore, glioma patients have obvious survival difference. The development of intraoperative auxiliary means has greatly contributed to surgical resection of glioma and remarkably increased therapeutic effects. The development of sensitizer realizes the combination of radiotherapy and chemotherapy and can improve the anti-tumor effects of oral temozolomide. Molecular markers and signal pathways involved in glioma, such as isocitrate dehydrogenase-1 mutation, epidermal growth factor amplification, high expression of vascular endothelial growth factor, Notch signal pathway, miRNA, etc. are involved in the occurrence and development of glioma and have an obvious impact on the proliferation, metastasis and invasion of glioma. They are potential molecular targets for the clinical treatment of glioma. Many different immunotherapy schemes are actively carried out in patients with glioma, but the unique tumor immune microenvironment of the central nervous system needs to be considered. This paper reviews the treatment progress of glioma in recent years.

Screening of novel miRNAs targeting EZH2 3' untranslated region using lentivirus miRNAs library and their expressions in breast cancer cells and tissues / 南方医科大学学报

<p><b>OBJECTIVE</b>To screen novel miRNAs targeting EZH2 3' untranslated region (UTR) in recombinational MCF-7 breast cancer cells over-expressing EZH2 3' UTR and quantitative analyze the expressions of the screened miRNA in breast cancer cells and tissues.</p><p><b>METHODS</b>A lentiviral library was transfected into the recombinant cell line MCF-7. The cells were screened with cytotoxic agents before extraction of the genome for amplification of the miRNA precursors using PCR. The screened miRNAs were identified with sequence analysis and their expressions were analyzed quantitatively with real-time PCR in breast cancer cells and tissues.</p><p><b>RESULTS</b>Seven miRNAs were screened from the recombinant MCF-7 cells, namely miR-15b, miR-16-2, miR-181b2, miR-217, miR-224, miR-329-1, and miR-487b, all of which failed to be predicted by bioinformatics software. Real-time PCR showed that miR-217, miR-329-1, and miR-487b were over-expressed in MCF-7 cells, and the expression of miR-15b and miR-16-2 was significantly increased in cancer tissues compared with the adjacent tissues (P<0.05).</p><p><b>CONCLUSION</b>Novel targeted miRNAs that can not be predicted by bioinformatics software were successfully screened from MCF-7 breast cancer cells over-expressing EZH2 3' UTR. These miRNAs are expressed differentially between normal breast cells and breast cancer tissues.</p>