Abstract B36: Contrasting views on the role of mesenchymal stem cells in tumor progression: A systematic review

Abstract

Abstract The role of mesenchymal stem cells (MSCs) in the progression of tumor remains controversial. Strong experimental evidences support both inhibitory and stimulatory roles of MSCs on tumor growth. To assess factors responsible for contrasting effects of MSCs on tumor growth, we did a systematic review of existing literature on the effect of MSCs on tumor growth from 01/01/00 - 01/05/16. A total of 168 original research articles with 315 experiments were assessed. Factors considered in the complex relationship between MSCs and tumor growth include: type of experiments (in-vivo, in-vitro), experimental models for the in-vivo studies (syngeneic or xenogeneic), immune status of the experimental animal (competent or deficient), sources and types of cancer and MSCs, status of the MSCs (naïve or engineered), methods of inducing cancer as well as methods of administering the MSCs in vivo and methods used in the in vitro experiments (co-culture or conditioned media). 55% of the studies favor the stimulatory effect of MSCs on tumor growth. The type of experiment is divided almost evenly, as about 53% of all the experiments were conducted in-vitro with 60% of the cancer cells exposed to the MSCs via co-culture methods. 78% of the in-vivo experiments were xenogeneic and 63% of these were carried out in immunocompetent animals. About 80% of both MSCs and cancer cells were sourced from human and 86% of these MSCs were used in their naïve form while 14% were engineered to produce factors that could alter the activity of the MSC itself or that of the cancer cells. About 61% of the MSCs were derived from bone marrow while 15% each were derived from adipose tissues and umbilical cord the remaining 8% MSCs were derived from other various tissues. Tumor growth was inhibited in 86% of experiments that used engineered MSCs. Tumor growth was inhibited in 82% of experiment that used umbilical cord MSCs while tumor growth was promoted in 62% of experiment that employed bone marrow MSCs, but the effect of MSCs on tumor growth was about 57% and 43% stimulatory and inhibitory respectively when adipose tissue derived MSCs were used. Thus several factors determine what effect MSCs would have on the progression of tumor growth. Note: This abstract was not presented at the conference. Citation Format: Ahmed Kolade Oloyo, Michael Sean Pepper. Contrasting views on the role of mesenchymal stem cells in tumor progression: A systematic review [abstract]. In: Proceedings of the AACR International Conference: New Frontiers in Cancer Research; 2017 Jan 18-22; Cape Town, South Africa. Philadelphia (PA): AACR; Cancer Res 2017;77(22 Suppl):Abstract nr B36.