Advance in the chemotherapy resistance of retinoblastoma / 国际眼科杂志(Guoji Yanke Zazhi)

Retinoblastoma(RB)is the most common intraocular malignant tumor of children. Chemotherapy is a preferred method in RB treatment, which includes intravenous chemotherapy, intra-arterial chemotherapy and intravitreal chemotherapy. However, the occurrence of chemotherapy resistance often leads to the failure of eye-preserving treatment in RB patients. Therefore, exploring the mechanism of the occurrence of chemotherapy resistance and searching for new strategies and combined medicines for RB treatment are of great clinical significance. This article reviews that RB cells obtain chemotherapy resistance through ATP binding cassette protein(ABC transporter), non-coding RNA, epigenetics modification, autophagy, epithelial mesenchymal transformation, extracellular matrix changes and other ways, and the potential therapeutic targets for chemotherapy resistance are also summarized, in the hope of providing some references for further research on chemotherapy resistance of RB.

Synergistic effect on biosynthesis of Panax notoginseng saponins by overexpressing a transcription factor PnbHLH and RNA interference of cycloartenol synthase gene / 中国中药杂志

This study cloned the transcription factor gene PnbHLH which held an open reading frame of 966 bp encoding 321 amino acids. This study constructed the overexpression vector of transcription factor PnbHLH of Panax notoginseng. The combination of PnbHLH overexpression and RNAi of the key enzyme gene PnCAS involved in the phytosterol biosynthesis was achieved in P. notoginseng cells, thus exploring the biosynthetic regulation of P. notoginseng saponins(PNS) by the synergistic effect of PnbHLH overexpression and PnCAS RNAi. The results showed that the PnbHLH transcription factor interacted with the promoters of key enzyme genes PnDS, PnSS and PnSE in the biosynthetic pathway of PNS, and then regulated the expression levels of key enzyme genes and affected the biosynthesis of saponins indirectly. Further study indicated that the synergistic effect of PnbHLH overexpression and PnCAS RNAi was a more effective approach to regulate the biosynthesis of saponins. Compared with the wild type and PnCAS RNAi cells of P. notoginseng, the contents of total saponins and monomeric saponins(Rd, Rb_1, Re, Rg_1 and R_1) were increased to some extent in the cell lines of PnbHLH overexpression and PnCAS RNAi. This indicated that the two ways of forward regulation and reverse regulation of saponin biosynthesis showed superposition effect. This study explored a more rational and efficient regulation strategy of PNS biosynthesis based on the advantages of multi-point regulation of transcription factors as well as the down-regulation of by-product synthesis of saponins.