Induction of Apoptotic Death and Cell Cycle Arrest in HeLa Cells by Extracellular Factors of Breast Cancer Cells

Abstract

Background: There are evidences on the role of extracellular factors in cellular communication between cancer<br />cells and non-cancerous cells to support tumor progression and a phenomenon of cancer cachexia. However, evidences<br />are scarce to show the effects of extracellular factors from one carcinoma microenvironment upon growth and survival<br />of another carcinoma. Methodology: To address the above issue, we have selected excised breast carcinoma tissue<br />samples and in vitro grown MCF-7 sources of extracellular factors and tested their effects to evaluate growth and<br />proliferation inhibitory potential against a cervical carcinoma cell line HeLa. Results: Data from the in vitro experiments<br />like Trypan blue dye exclusion, MTT assay, cell cycle assay and annexin V/PI staining lead us to suggest that the<br />extracellular factors collected from the culture medium of in vitro grown MCF-7 and excised breast carcinoma tissue<br />play an apoptosis inducing and cell cycle arrest role in HeLa. In these in vitro experiments, we detected the presence of<br />up to 40-50% apoptotic cell death in HeLa cells and increase in G2-M cell cycle phase from 11%-25% due to treatment<br />with extracellular factors from human breast carcinoma cells. Discussion and Conclusion: These observations are<br />novel and suggest that extracellular factors from breast carcinoma play an apoptosis inducing and growth inhibitory<br />role upon on HeLa cells. This study can also support the concept of cancer cachexia and a possible hypothesis for rare<br />chance of synchronous two or more primary tumor in a single patient.