Maackiain inhibits proliferation and promotes apoptosis of nasopharyngeal carcinoma cells by inhibiting the MAPK/Ras signaling pathway / 中国天然药物

Nasopharyngeal carcinoma (NPC) is the third most common malignancy with a high recurrence and metastasis rate in South China. Natural compounds extracted from traditional Chinese herbal medicines have been developed and utilized for the treatment of a variety of cancers with modest properties and slight side effects. Maackiain (MA) is a type of flavonoid that was first isolated from leguminous plants, and it has been reported to relieve various nervous system disorders and exert anti-allergic as well as anti-inflammatory effects. In this study, we demonstrated that MA inhibited proliferation, arrested cell cycle and induced apoptosis in nasopharyngeal carcinoma CNE1 and CNE2 cells in vitro and in vivo. The expression of the related proteins associated with these processes were consistent with the above effects. Moreover, transcriptome sequencing and subsequent Western blot experiments revealed that inhibition of the MAPK/Ras pathway may be responsible to the anti-tumor effect of MA on NPC cells. Therefore, the effects of MA and an activator of this pathway, tertiary butylhydroquinone (TBHQ), alone or combination, were investigated. The results showed TBHQ neutralized the inhibitory effects of MA. These data suggest that MA exerts its anti-tumor effect by inhibiting the MAPK/Ras signaling pathway and it has the potential to become a treatment for patients with NPC.

Identification and functional analysis of a novel phospholipase D2 gene mutation associated with familial systemic lupus erythematosus / 中南大学学报(医学版)

OBJECTIVES@#Systemic lupus erythematosus (SLE) is a kind of autoimmune inflammatory connective tissue disease which seriously endangers human health. Genetic factors play a key role in the pathogenesis of SLE. This study aims to investigate a novel phospholipase D2 (PLD2) mutation associated with familial SLE, and further explore the underlying mechanism of the mutation in SLE.@*METHODS@#The blood samples from a SLE patient, the patient's parents, and 147 normal controls were collected and DNA was extracted. Whole genome high-throughput sequencing was performed in the patient and her parents and the results were further analyzed by various bioinformatics methods. The wild type (wt), mutant type (mu), and negative control PLD2 plasmids were further constructed and transfected into 293 cells. The expression level of HRAS protein in 293 cells was detected by Western blotting.@*RESULTS@#In this SLE family, the female SLE patient and her mother, 1 in generation II and 1 in generation III had typical clinical manifestations of SLE, and all of them had lupus nephritis at early stage. The genetic characteristics are consistent with autosomal dominant inheritance. A novel PLD2 heterozygous mutation (c.2722C>T) was found in the patient and her mother, but not in her father and other normal controls. Compared with wtPLD2 plasmid and negative control PLD2 plasmid, the expression of HRAS in 293 cells transfected with muPLD2 plasmid was significantly up-regulated (both @*CONCLUSIONS@#PLD2 c.2722C>T mutation may be one of the pathogeny of SLE in this family.

ANT2 suppression by shRNA restores miR-636 expression, thereby downregulating Ras and inhibiting tumorigenesis of hepatocellular carcinoma

MicroRNAs (miRNAs) participate in diverse biological functions and carcinogenesis by inhibiting specific gene expression. We previously reported that suppression of adenine nucleotide translocase 2 (ANT2) by using the short hairpin RNA (shRNA) approach has an antitumor effect in several cancer cells. We here examined the influence of ANT2 on expression of miRNAs in hepatocellular carcinoma (HCC) to further elucidate the tumor-suppressive mechanism of ANT2 shRNA. We first carried out screening for miRNAs, whose expression is regulated by ANT2 suppression in the Hep3B HCC cell line using miRNA microarrays. Validation of candidate miRNAs was done by incorporating clinical samples, and their effects on the tumorigenesis of HCC were studied in vitro and in vivo. miR-636 was one of the miRNAs whose expression was highly upregulated by ANT2 suppression in miRNA microarray analysis, as confirmed by real-time reverse transcription-polymerase chain reaction. Notably, miR-636 was markedly downregulated in HCC tissues compared with matched non-neoplastic liver in clinical samples. Restoration of miR-636 in Hep3B cells led to significant reduction of cell proliferation and colony formation. miR-636 restoration resulted in a decreased level of Ras, one of the putative targets of miR-636, and inactivation of its signaling pathway. Moreover, tumorigenesis was efficiently suppressed by miR-636 in an in vivo tumor xenograft model of HCC. The data suggest that miR-636 might function as a tumor suppressor miRNA affecting HCC tumorigenesis via downregulation of Ras, and that ANT2 suppression by shRNA could exert an anticancer effect by restoring miR-636 expression in HCC.