Objective: To study the synergistic effect of thermotherapy and chemotherapy with chemotherapy on lung tumor cell growth in order to explore its underlying mechanisms.
Methods: A549 cells were treated by combination of 43 degrees C and 50 microg/L Paclitaxel, and 43 degrees C or 50 microg/L Paclitaxel alone. MTU assay and Wound-healing assay were used to measure the survival and the invasive capacity. Phosphorylation of JNK and expression of HSP70 were determined with Western Blotting. Cells without treatment were used as controls.
Results: In comparison with cells treated with 43 degrees C and 50 microg/L Paclitaxel alone, or with combination of 43 degrees C and 50 microg/L Paclitaxel and SP600125, the proliferation rate of cells subjected to combination treatment of 43 degrees C and 50 microg/L Paclitaxel decreased significantly (P > 0.05). There were no significant differences in cell proliferation between untreated cells and the cells treated with 43 degrees C heat, 50 microg/L Paclitaxel and SP600125 (P > 0.05). The invasive capacities of the cells treated combination of 43 degrees C heat and 50 microg/L Paclitaxel were markedly reduced in comparison to other treatment groups. Also phosphorylations of JNK were significantly elevated in comparison to untreated cells or the cells only underwent chemotherapy (P < 0.05). The expression levels of HSP70 on thermotherapy in combination with chemotherapy were more lower than those in thermotherapy group (P < 0.05).
Conclusion: Thermotherapy in combination with chemotherapy showed more strong inhibitory effect than those of thermotherapy or chemotherapy alone on lung tumor cell growth. The resultant phosphorylation of JNK and inhibition of HSP70 expression could be responsible for this effect.