Inhibition of tumor growth by intramuscular administration of the canstatin gene delivered by electroporation / 中国医师杂志

Objective To construct human canstatin gene eukaryotic expression vector and investigate the therapeutic effect of intramuscular canstatin gene delivered by electroporation on tumor growth.Methods Canstatin cDNA was amplified from total RNA extracted from fresh fetal liver by reversing transcription polymerase chain reaction (RT-PCR).The canstatin cDNA fragment was in serted into pEGFP-N1 eukaryotic expression vector.The recombination plasmid was delivered to the quadriceps of the mice with Lewis lung carcinomas by electroporation intramuscular.Fluorescence intension measured by fluorescence microscope,reverse-PCR assay,and immunohistochemistry assay were performed to detect the expression of canstatin gene in the muscle and in circulation.The tumor weight and volume were used to detect the biological effects of canstatin gene delivery.Results Recombinant eukaryotic expression vector of recombinant human canstatin was successfully constructed.The canstatin mRNA was significantly increased in the skeletal muscle and intramuscular delivery of canatatin gene by electroporation acquired the expression of enhanced green fluorescent protein (EGFP)/canstatin protein in the circulation and significantly inhibited tumor growth.The percent of the inhibition of tumor weight was 57.7 ％.Conclusions Electroporation mediated gene transfer efficiency in skeletal muscle was compared to simple plasmid injection and lasted for a long time.It was an efficient and safe,convenient and economic,gene transfer methods and might have certain clinical application value.Electroporation mediated canstatin gene transfer in skeletal muscle had obvious inhibitory effect on Lewis lung cancer in mice subcutaneous xenograft tumor growth.

RELATIONSHIP BETWEEN DEGREE OF INVASION AND TUMOR METASTASIS / 中国癌症杂志

PURPOSE To provide evidence for the relationship between degree of invasion and tumor metastasis. The tumor cells of transplantable mouse histiocytic sarcoma (L1) were inoculated at the right hind footpads of inbred 615-strain mice. METHODS Once bearing the tumor, all the mice were sacrificed respectively on the 1st. 3th, 5th. 10th, 20th, 30th, and 40th day as to observe the degree of tumor invasion and the process of tumor metastasis. RESULTS When the degree of tumor invasion was grade Ⅲ or Ⅳ , the metastasis of tumor cells was found earliest in draining lymph nodes. However, the tumor metastasis in lung appeared later than in lymph nodes. CONCLUSION According to the time of tumor growth and degree of invasion and metastasis, the authors suggest a new classification for cancer staging, namely, latent, invasive and metastatic stages. During the stage of tumor invasion, it is redivided into early, middle and late invasive phases. During the stage of tumor metastasis, it is redivided into early, middle and late metastatic phases.