Background: Cancer-associated mesenchymal stem cells (CA-MSCs) are MSCs present in the tumor microenvironment. Over the last decade, studies have demonstrated that CA-MSCs can, directly and indirectly, interact with the tumor microenvironment to promote or inhibit tumour growth. Therefore, understanding the interactions of CA-MSCs with tumor cells is critical to disease progression and response to therapy. Development of chemo-radio-resistance in cervical cancer is a major cause of mortality in developing countries like India, so in this study, we have focused on the interaction of CA-MSCs with chemo-radio-resistant cervical cancer cells developed in our laboratory.
Methodology: CA-MSCs were isolated from biopsy samples of cervical cancer patients via explant method and characterized as per ISCT guidelines. Further, an in vitro chemo-radio-resistant cervical cancer cell line, HeLa (HeLa-CRR), was established by a fractionated treatment to cisplatin and megavoltage X-rays and was made resistant up to 2.5µM cisplatin + 50Gy. It was characterised via viability assay, clonogenic survival, cell cycle analysis, apoptosis assay and g-H2AX staining and compared to a sham-treated group (HeLa-NR). CA-MSCS were then co-cultured directly or indirectly (conditioned media) with HeLa cells to decipher the effect of CA-MSCs on cancer proliferation, migration, invasion, sphere formation abilities and response to chemo-radiotherapy.
Results: Isolated CA-MSCs were positive for CD105, CD73 and CD90 and negative for CD45, CD34 and HLA-DR and showed trilineage differentiation potential. Establishment of HeLa-CRR was confirmed by increased cell viability and clonogenic survival. HeLa-CRR also showed shortened G2/M phase, lower apoptosis and lesser number of g-H2AX foci compared to HeLa-NR. Co-culturing of CA-MSCs with HeLa-CRR/NR led to a significant increase in proliferation, migration, invasion and sphere formation ability of the cancer cells. Co-cultured cells also showed an altered response to chemo-radiotherapy .
Conclusion: This study revealed that CA-MSCs from cervical cancer patients showed pro-tumorigenic activity and affected therapeutic response in HeLa-NR and Hela-CRR cells.