Study on the Relevance of Inducing Apoptosis and Reversal Effect of Nilotinib In Combination with Tet on Multidrug Reststahoe of K562/A02 Cell Line

Abstract

4951 Objective To investigate the relevance of Inducing apoptosis and reversal effect of nilotinib in combination with Tet on multidrug reststahoe of K562/A02 cell line and its mechanism. Methods Methyl-thiazol tetrazolium(MTT) assay is employed to examine the pharmacological effect of Nilotinib or Tet alone on K562/A02 cell line, to calculate the inhibitor concerntration 50(IC50) of daunorubicin(DNR) in K562/A02 cell line and the resistance multiple of DNR to K562/A02 cell line. Flow cytometry(FCM) was employed to comple the effect on the inducing apoptosis of K562/A02. The expression of bax/survivin mRNA was determined by RT-PCR, and the expression of bax/survivin protein was assessed by Western blot. Results After 48 h 5 nmol/L nilotinib or 1.0μmoL/L Tet treatment, IC50 of DNR to K562/A02 was 5.71mg/L or 6.52 mg/L respectively;While on combinative treatment, its IC50 decreased to 3.12 mg/L. Nilotinib or Tet alone was able to increase the DNR induced apoptosis rate of K562/A02 cell (P<0.05), while on combination treatment the apoptosis rate increased remarkably. After 48 h 5 nmoL/L nilotinib or 1.0μmoL/L Tet treatment alone, gray—scale vaule of bax mRNA Was 2.90±0.31 or 3.6±0.46, respectively Gwhile on combinative treatment the value increased to 5.9±0.98. The bax protein expression level in K562/A02 cells was 2.1±0.07 or 2.90±0.09 when treated with 5 nmoL/L nilotinib or 1.0μmoL/L Tet alone for 48 h, but on combination treatment, the level increased to 4.8±0.31. After 48 h 5 nmoL/L nilotinib or 1.0μmoL/L Tet treatment alone, gray—scale vaule of survivin mRNA was 0.70±0.01 or 0.55±0.02, respectively;while on combinative treatment the value decreased to 0.35±0.08. The survivin protein expression level in K562/A02 cells was 0.74±0.03or 0.61±0.04 when treated with 5 nmoL/L nilotinib or 1.0μmoL/L Tet alone for 48 h, but on combination treatment, the level decreased to 0.42±0.06. Conclusion Nilotinib or Tet alone can pattially reverse drug resistance of K562/A02 cells. There is resistance phenomena of DNR to K562/A02 cells, and Nilotinib or Tet alone alone is able to reserve the resistance of DNR and enhance the inducing apoptasis effect of DNR. The mechanism may be associated with the increase of bax mRNA and protein expression and decrease of survivin mRNA and protein expression and increase of the apoptosis rate. And there is a synergistic action with these two agants in combination. Disclosures: No relevant conflicts of interest to declare.

Tyrosine kinase inhibitors enhanced the efficacy of conventional chemotherapeutic agent in multidrug resistant cancer cells

“…What’s more, in nude mouse MDR xenograft models, combination of nilotinib and doxorubicin hampered tumor growth compared with those treated doxorubicin alone ( P < 0.05), indicating nilotinib potently reverses ABCB1-mediated resistance to doxorubicin both in vitro and vivo [ 79 ]. Note that a study conducted by Chen et al compared BrTet treatment alone and the combination of nilotinib and BrTet in K562/A02 cells, thus found the latter (IC 50 ) significantly decrease [ 80 ], suggesting the potential function of nilotinib as chemosensitizer.…”