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This study was purposed to investigate the apoptosis-inducing effect of Annexin A2 gene (AnxA2) on multiple myeloma (MM) cells and its mechanisms. The human MM cell lines U266 and RPMI8226 were transfected by using siRNA targeting at AnxA2; the expressions of AnxA2 mRNA and protein in the siRNA-transfected cells were detected by real-time PCR and Western blot, respectively; the cell apoptosis was assayed by flow cytometry. The results showed that silencing AnxA2 gene by siRNA resulted in decreased expressions of AnxA2 gene and protein, increased apoptosis of U266 and RPMI8226 cell lines (P < 0.05), at the same time resulted in down-regulation of apoptosis-related gene expressions including p65NF-κB, IL-2, IL-6 (P < 0.05), and up-regulation of P53 gene expression (P < 0.05). It is concluded that the AnxA2 silence plays a promoting role in apoptosis of MM cell lines U266 and RPMI8226.

Mobile phones are widely used globally. However, the biological effects due to exposure to electromagnetic fields (EMF) produced by mobile phones are largely unknown. Environmental and occupational exposure of humans to gamma-rays is a biologically relevant phenomenon. Consequently studies were undertaken to examine the interactions between gamma-rays and EMF on human health. In this study, exposure to 900-MHz EMF expanded gamma-ray damage to SHG44 cells. Preexposure EMF enhanced the decrease in cell proliferation induced by gamma-ray irradiation and the rate of apoptosis. The combination of EMF and gamma-ray exposure resulted in a synergistic effect by triggering stress response, which increased reactive oxygen species, but the expression of hsp70 at both mRNA and protein levels remained unaltered. Data indicate that the adverse effects of gamma-rays on cellular functions are strengthened by EMF.

Background & Objective: Researches have shown that ultrasound can enhance the sensitivity of tumor cells towards chemotherapy drugs, thus to inhibit cell proliferation. This study was to investigate the antitumor effect of low-frequency ultrasound combined with adriamycin on human leukemia multidrug resistance (MDR) cell line K562/A02., Methods: K562/A02 cells were divided into four groups: blank control group, adriamycin group, ultrasound group, and adriamycin plus ultrasound group. The trypan blue dye exclusion assay and MTT assay were used to determine the viability and proliferation of K562/A02 cells, while Wright's stain and flow cytometry were used to determine the apoptosis and the concentration of adriamycin. The expression of P-glycoproteins (P-gp) was detected using immunocytochemistry., Results: Ultrasound (20 kHz, 0.25 W/cm2, 60s) combined with adriamycin (7.5 microg/mL) induced more apoptosis of K562/A02 cells than adriamycin alone. Compared with the adriamycin group, ultrasound at a frequency of 20 kHz and an intensity of 0.5 W/cm2 exerted an acute killing effect on cells. Ultrasound increased the intracellular concentration of adriamycin and promoted apoptosis of K562/A02 cells, but did not change the expression of P-gp on the cell membrane., Conclusion: Ultrasound at a frequency of 20 kHz, an intensity of 0.25 W/cm2 and duration of 60s can enhance the killing effect of adriamycin on K562/A02 cells.