Stem Cells in Tumour Microenvironment Aid in Prolonged Survival Rate of Cancer Cells and Developed Drug Resistance: Major Challenge in Osteosarcoma Treatment.

Osteosarcoma is an aggressive bone cancer found in children and adolescents. The combined treatment strategy includes the surgical removal of tumour and subsequent chemotherapy to prevent the reoccurrence has been a widely accepted approach. However, the drug resistance developed by tumour cells causes recurrence of cancer. It is imperative to understand the molecular mechanism involved in the development of drug resistance and tumour progression for developing potential therapy. Tumour microenvironment and cellular cross-talk via activation of various signalling pathways are responsible for tumour progression and metastasis. The comprehensive reviews are already available on the tumour microenvironment, signalling cascades responsible for tumour progression, and cellular crosstalk between malignant cells and immune cells. Therefore, we intend to provide comprehend review postulating the importance of mesenchymal stem cells (MSCs) in osteosarcoma progression and metastasis. This paper is aimed to provide information sequentially includes: tumour microenvironment, MSCs role in osteosarcoma progression, the hypoxic environment in MSCs recruitment at the tumour site and the importance of exosomes in tumorigenesis, progression and metastasis. Overall, this review may enlighten the research on the role of MSCs and MSCs derived exosome in osteosarcoma progression and drug resistance. This possibly may result in developing novel therapeutic approaches to combat the osteosarcoma effectively and contributes for the development of prognosis tools for early diagnosis.