The Role Of Sp1 Up-expression In Drug Resistance Of The Small Cell Lung Cancer Cells

Objective: Small cell lung cancer (SCLC) is a special histologic type of bronchogenic carcinoma. It malignancy is highest and prognosis is extremely poor in all types of human lung cancers. It may be effectively treated by chemotherapeutics initially in the clinic, but it soon developed the multidrug resistance (MDR). MDR is one of the reasons that result in the failure of SCLC chemotherapy. MDR is a special broad spectrum drug resistant phenomenon. Once cancer cells develop resistance to a certain anticancer drug, it will resist to many other drugs that are structurally and chemically unrelated.At present, a plenty of research were done on the mechanis of cancer MDR and its reversal, which mainly centralized on membrane protein that perform drug pump role, such as P-glycoprotein and etc, it was called classic drug resistance. But the study on non-classic drug resistance such as abnormal endocellular enzyme including topoisomerase II to bring out MDR was few.Etoposide (VP-16) is one of the derivatives of podophyl- lotoxin and belongs to DNA topoisomerase II (Topo II) inhibitor. The inhibition of Topo II is known to be a major mechanism for the action of VP-16 by stabilizing the cleavable complexes and...