Combined ultrasound-curcumin treatment of human cervical cancer cells

Objectives: Human papillomavirus (HPV) is associated with cervical cancer. Studies showed curcumin inhibits HPV oncogenes expression but curcumin has low bioavailability. The objectives were: (1) to study ultrasound enhancement of curcumin effects on HeLa, SiHa and C33A, (2) to compare two frequencies for sonoporation and (3) to detect cell-free DNA released by the treatment.

Study design: HeLa, SiHa and C33A cells (non-HPV control) were processed and exposed to either: (1) 10μM curcumin only, (2) 10μM curcumin with 8s of 7.5MHz ultrasound, (3) 10μM curcumin with 8s of 5.0MHz ultrasound, (4) control medium, or (5) 8s of 7.5MHz ultrasound. The five treated groups were incubated (48h) and analyzed by dual fluorescence apoptosis/necrosis assay. DNA in spent media was analyzed by capillary analysis.

Results: Combined curcumin ultrasound resulted in 9-, 12- and 16-fold higher necrosis in HeLa, SiHa and C33A cells respectively. Increased necrosis correlated with higher ultrasound frequencies. There was increased apoptosis in HeLa or SiHa cells with the combined treatment. Curcumin alone resulted in a lesser 2-4-fold increase in necrosis in the groups. Cell-free DNA was detected in the spent media of HeLa and SiHa but not C33A cultures.

Conclusions: The results showed enhanced necrosis in cervical carcinoma cell lines after combined treatment and confirmed the ultrasound capacity to increase effectiveness of curcumin. Cancer cells were smaller post-treatment suggesting microtubule structural disruption. Cell-free DNA was low molecular weight consistent with lysed host cell.