Study On The Effects Of Hyperthermia Combined With Chemotherapy On Human Lung Cancer Cells A549 And SBC5

BACKGROUND Lung cancer is one of the commonest malignant tumors threatening the health of human being. Its incidence rate and mortality rate are both very high. The high mortality of lung cancer is because that radiotherapy alone or chemotherapy alone can not control cancer. Hyperthermia has become the fifth method after surgery, radiotherapy chemotherapy and bio-therapy in resent years. Hyperthermia combined with radiotherapy or chemotherapy is being used more and more widely in the treatment of lung cancer, but the lagged theoretical research is still the obstacle of the progression in clinical practice.The research on the sensitivity of hyperthermia to different tumor cells has never been reported in and out of domestic, and possible molecular mechanisms are worth of being investigated. Navelbine, Cisplatin, Taxotere, Gemzar, Etoposide, are all effective chemotherapy agents in cancer treatment, but their effects of combined with hyperthermia is not known. In the study, A549 and SBC-5 cell lines were used to explore the sensitivities to hyperthermia, as well as the possible mechanism. Furthermore the combined effects could be evaluated and the theoretical basis could be provided for triall practice. METHODS 1,The working concentrations of NVB, DDP, TAX, GEM, VP-16 against human pulmonary adenocarcinoma cells(A549) and human small cell lung cancer cells(SBC-5) were determined by MTT assay that had been developed for quantitative evaluation of the proliferation of cells. Then hyperthermia and chemotherapy were used singly or concurrently and the cell survival rates were obtained at 24h. The anticancer effect was evaluated by Veleriote method;2,The changes in cell cycle of A549 cells and the assessment of apoptosis rates after treated with 42℃hyperthermia and NVB were analyzed by flow cytometry (FCM);3,The changes in cell cycle of SBC-5 cells and the assessment of apoptosis rates after treated with 42℃hyperthermia and VP-16 were analyzed by flow cytometry(FCM);4,The changes of SBC-5 cell ultra microstructures were detected by electron microscope after different treatments.RESULTS 1,The concentrations were defined as that of IC10～IC20 at 24h. It turned out: NVB 1ug/ml, DDP 0.1ug/ml, TAX 1ug/ml, GEM 0.1ug/ml, VP-16 0.1ug/ml. Both single hyperthermia and single chemotherapy suppressed the proliferation of A549 and SBC-5 cells (P < 0.05);Combination of hyperthermia and chemotherapy suppressed proliferation and killed more cells than single chemotherapy and single hyperthermia(P<0.01); The anticancer effect was evaluated by Veleriote method: NVB, DDP, TAX, GEM, VP-16 combined with hyperthermia can enhance the suppressing effects .2,(A549)Flow cytometry showed that 42℃hyperthermia(42℃,1h) resulted in progressive decrease in cells in S phase; the chemotherapy group (NVB,1ug/ml) arrested cell cycle progression in G2/M phase; compared with the group of single chemotherapy(NVB,1ug/ml), the proportion of S phase cells of the group of combined treatment of 42℃hyperthermia and chemotherapy (42℃+ NVB,1ug/ml,1h)decreased while the proportions of G2/M phase cells increased. The apoptosis rates of the four groups (control group, hyperthermia group, chemotherapy group and combination group) are 1.5%,7.9%,13.9%and 29.1% respectively;3,(SBC-5)Flow cytometry showed that: 42℃hyperthermia(42℃,1h) resulted in progressive decrease in cells in S phase; the chemotherapy group (VP-16,0.1ug/ml)arrested cell cycle progression in G2/M phase; Compared with the group of single chemotherapy(VP-16,0.1ug/ml), the proportion of G2/M phase cells of the group of combined treatment of 42℃hyperthermia and chemotherapy(42℃+ VP-16,0.1ug/ml,1h) decreased while the proportions of S phase cells increased. The apoptosis rates of the four groups(control group, hyperthermia group, chemotherapy group and combination group) were 3.3%,6.9%,10.3% and 21.1% respectively.4,Under transmission electron microscope we found SBC-5 that the control group cell membrane is integrity, cell organ is normal, nuclear chromatin is uniformity, nucleolus is clear, cell nucleus is big; the hyperthermia group (42℃,1h) nuclear chromatin is agglutinate, nuclear membrane is integrity, cell organ is constit engorge; the chemotherapy group (VP-16,0.1ug/ml)cell is shrinkage, cytoplasm is concentrate, nuclear chromatin is enriched at nuclear membrane; the combined hyperthermia with chemotherapy group (42℃+ VP-16,0.1ug/ml,1h) cell chipped to apoptotic body, cell membrane is integrity, chromatin is uneven in each apoptotic.CONCLUSION 1,Both single hyperthermia and single chemotherapy suppressed the proliferation of A549 and SBC-5 cells(P<0.05); 2,The sensitivity of hyperthermia,combined hyperthermia and chemotherapy to SBC-5 is higher than A549;3,Combined hyperthermia and chemotherapy can obviously enhance the cytotoxicity of each one(P<0.01);4,The mechanism of anti-tumor is multiplicity ,may be related to disturbance of cell cycle and cell ultramicrostructure.