Ribosomal protein L23 is a new target for gene therapy of cancer.It participates in tumor progression by activating p53,inactivating murine double minute 2,regulating the carcinogenic activity of c-Myc,inducing the multi-drug resistance,and affecting the biologic behaviour of tumors.Generally,it′s con-sidered to be a potential prognostic factor in human cancers.

Dihydroartemisinin (DHA),the major active metabolite of artemisinin,participates in tumor progression through the following ways:forming free radicals to induce cancer cells death dependent on iron,inducing apoptosis,inhibiting angiogenesis,tumor cells invasion and metastasis,modulating muhidrug resistance,controlling intracellular Ca2+ concentration,regulating cell cycles,cell autophagy and the immune system and so on.Generally,it is considered to be a potential anti-tumor drug.

Ob jective To construct and screen out the RPL 23-siRNA interference fragments ,providing the basis for the following experiments about the correlation with RPL 23 and gastric cancer .Methods The RPL23-siRNA,synthesized chemically through lipofection ,were selected from three target sequences by RNA in-terference and detected by real -time PCR and Western blot .Results Compared with normal cell group and RPL23 control group ,the mRNA and protein expression of RPL 23 in the other 3 interference groups were signifi-cantly decreased(P<0.01).Multiple comparisons showed that the interference efficiency of RPL 23 -siRNA1 group was significantly higher than that of RPL 23-siRNA2 group and RPL23-siRNA3 group(P<0.01).Con-clusion The RPL23-siRNA interference fragment can be successfully constructed and screened out ,which pro-vides the basis for the following experiments .

Muhidrug resistance (MDR) is one of the important reasons for the failure of clinical anticancer drugs,involving multiple mechanisms.Among them,the classical MDR mechanism mediated by P-glycoprotein (P-gp) is closely related to the formation of MDR,which can excrete intracellular chemotherapeutic drugs through the "drug pump" effect and significantly reduce the therapeutic effect.Curcumin is mainly extracted from the underground rhizome of Chinese medicine turmeric,with a wide range of pharmacological activity.Recent studies have found that curcumin also has a role in reversing the MDR of the tumor,by inhibiting both P-gp function and expression,and this process involves a variety of signal paths.