Doxorubicin Affect The Expression Of ABCB1 In Human Hepatoma Cell Line HepG2

Objective: Primary liver cancer is a malignant tumor which is common in China,and it is the second cause of tumor mortality in our country.Although surgical resection is the preferred treatment for liver cancer,the nature of cancer itself often leads to poor results,such as recurrence.Sometimes they had lost the optimal time for treatment when the liver cancer confirmed primary.Therefore,chemotherapy is important for patients to prevent from relapsing and metastasizing,and it can prolong survival time for patients and improve the quality of life.However,drug resistance is a problem that is hard to solve,and it has a bad effect on the efficacy of chemotherapy.There are a number of clinical evidences show that more than 90% death of cancer patients is closely related to drug resistance.Therefore,the molecular mechanisms of drug resistance in liver cancer cells may provide a theoretical basis for finding new therapeutic targets.At present,the main chemotherapy drugs for liver cancer are multitudinous,such as doxorubicin,paclitaxel,5-Fu and cisplatin,etc.These are the first-line chemotherapy drugs for liver cancer,at the same time,they also have caused the multidrug resistance(MDR).ABCB1 multidrug resistance gene located on human chromosome long arm of the 7th District 2 band 1,belonging to ABC(ATP-binding cassette)transporter family.Their overexpression becames the main reason for the of tumor resistance to chemotherapy,but the relationship between the expression of ABCB1 and drug resistance has not been reported now.So a detailed study is crucial to investigate ABCB1 and liver cancer’s drug resistance.Doxorubicin is an antitumor antibiotic,inhibiting the synthesis of RNA and DNA.The effect of RNA inhibition is the strongest.Doxorubicin has a broader anti-tumor spectrum.It belongs to non-cycle-specific drug,and has a killing effect on a variety of tumor cells which are living in all kinds of growth cycles.The efficacy of doxorubicin in chemotherapy has been recognized by oncologists and clinicians.For the reasons mentioned above,our study investigated the effect of doxorubicin on ABCB1 expression in normal HepG2 cell line,and researched the relationship between the expression of ABCB1 and Hep G2/Doxorubicin cell line’s drug resistance.Method: We cultured hepatoma cell line HepG2 routinely,and established doxorubicin-resistant cell lines(Hep G2/Doxorubicin).MTT assay is adopted to observe the inhibitory effect on human hepatoma HepG2 cells and Hep G2/Doxorubicin cell lines.RT-PCR and Western Blot are used to study the expression of ABCB1(mRNA and protein,respectively)in human hepatoma HepG2 cells and resistant cell lines of HepG2/Doxorubicin.Analyze the relevance between the inhibition ratio and ABCB1 mRNA levels to estimate the relationship between ABCB1 and HepG2 resistance.Results:1 HepG2 cells are spindle-shaped,closely-spaced and in the same size,adhering to the wall.There are clear boundary makers between cells.On the contrary,HepG2/Doxorubicin cells are growing slowly with irregular shape.They also increased in volume,and have concentrated nucleus.Cells are growing stackedly.2 The mRNA and protein levels of ABCB1 were tested by RT-PCR and Western blot respectively.Both of them in resistant strains were significantly higher than the parental cell.3 MTT assays the resistance of parental cells HepG2 and HepG2/Doxorubicin.Compared with the parental cells,doxorubicin-resistant cells in different concentrations have a lower inhibition ratio.Their difference is significant,showing a certain degree of resistance.4 Doxorubicin-resistant cells in different doxorubicin concentrations had a lower inhibition ratio which were negatively related with ABCB1 mRNA levels.That is to say,the higher ABCB1 mRNA levels,the lower inhibition ratio.It could provide clinical theoretical basis considering combination therapy for liver cancer patients and injecting liver cancer multi-resistant mechanism a new content.Conclusion: Doxorubicin can inhibit the proliferation of HepG2 cells.Human HepG2 resistant cell lines had significantly increased ABCB1 levels.As ABCB1 mRNA levels grows,increasedrelative resistance.It could provide clinical chemical drug treatment for liver cancer patients in the future,could provide certain theoretical basis for combination therapy for the perfection of the mechanism of liver cancer multi-resistant with new content.