Indication of participation of caspase-2 and caspase-5 in mechanisms of human cervical malignancy.

INTRODUCTION

When apoptosis is disrupted, the transformed cells can survive, proliferate, and evolve into a malignancy. The strictly conserved caspase genes and the reliable experimental data clearly show that some caspases play a crucial role in apoptosis even if some of them have no apoptotic activity and others exhibit both apoptotic and nonapoptotic properties. Although caspase-2 belongs to initiator caspases, its normal role remains unclear. Experimental studies have shown that it is primarily necessary for the execution of apoptosis in mutagenic cells. Human caspase-5 is classified as an inflammatory caspase, although its substrate has not been identified yet. In this research, the activities of caspase-2 and caspase-5 have been estimated during the progression of human cervical malignancy.

METHODS

The experimental material includes human cervical tissue samples (normal and pathological) and blood serum samples of the corresponding tissue donors, where enzyme activities have been measured colorimetrically.

RESULTS

Both caspases' activities showed the highest increase, statistically significant (P < 0.01, by t test) compared with the controls, in the low-grade squamous intraepithelial lesion tissues. Caspase-2 of all pathological tissues was proved more active than the controls. Serum caspases' activities were significantly lower than those of the tissues. Serum caspase-2's activity in patients with low-grade squamous intraepithelial lesion stage showed no statistically significant increase compared with the controls. Serum caspase-5's activity of all patients with malignancy stages was presented elevated, whereas that of the serum of patients with cervical cancer had the highest activity (P < 0.01, by t test).

CONCLUSIONS

The changes of caspase-2 and caspase-5 activities could be indicative of their involvement in the cervical malignancy mechanisms.