Effect of human Wharton's jelly mesenchymal stem cell secretome on proliferation, apoptosis and drug resistance of lung cancer cells

Abstract

Multipotent mesenchymal stem cells (MSCs) are recently found to alter the tumor condition. However their exact role in tumor development is not yet fully unraveled. MSCs were established to perform many of their actions through paracrine effect. Thus investigation of MSC secretome interaction with tumor cells may provide important information for scientists who are attempting to apply stem cells in the treatment of the disease. In this study we investigated the effect of human Wharton's jelly derived MSC (WJ-MSCs) secretome on proliferation, apoptotic potential of A549 lung cancer cells, and their response to the chemotherapeutic agent doxorubicin. WJ-MSCs were isolated from human umbilical cord and then characterized according to the International Society for Cellular Therapy criteria and WJ-MSC secretome was collected. BrdU cell proliferation assay and Annexin V-PI staining were used for the evaluation of cytotoxic and proapoptotic effects of WJ-MSC secretome on A549 cells. WJ-MSC secretome neither induced proliferation of lung cancer cells nor affected the apoptotic potential of the tumor cells. We also studied the combinatorial effect of WJ-MSC secretome and the anticancer drug doxorubicinwhich showed no induction of drug resistance when A549 cells was treated with combination of WJ-MSC secretome and doxorubicin. Although MSCs did not show antitumor properties, our in vitro results showed that MSC secretome was not tumorigenic and also did not make lung cancer cells resistant to doxorubicin. Thus MSC secretome could be considered safe for other medical purposes such as cardiovascular, neurodegenerative, and autoimmune diseases which may exist or occur in cancer patients.

Keywords: A549 lung cancer cells; Mesenchymal stem cells; Secretome.

Fig. 1

Morphological characteristics of WJ-MSCs. a; Confluent growth of mesenchymal stem cells in passage 4, b; Fibroblast like morphology of WJ-MSCs.

Fig. 2

Differentiation of WJ-MSCs to mesodermal lineages. b; Alizarin Red S staining shows successful differentiation into osteocytes and a; its undifferentiated negative control, d; Oil Red O staining shows successful differentiation into adipocytes and c; its undifferentiated negative control, f; Alcian Blue staining shows successful differentiation into chondrocytes and e; its undifferentiated negative control.

Fig. 3

Surface marker detection of WJ-MSCs. a; dot plot representation of cell population, b; Flowcytometric analyses showed lack of CD34, c; CD45 antigens, d; positive expression of CD73, e; CD90 and f; CD105 on WJ derived cells.

Fig. 4

BrdU proliferation assay. a; A549 cell proliferation did not change significantly before and after treatment with hWJ-MSC secretome (obtained from intact MSCs or IFNγ stimulated MSCs), b; WJ-MSC secretome did not induce resistance to doxorubicin in A549 cells because A549 cell proliferation did not change significantly when treated by doxorubicin alone or doxorubicin + hWJ-MSC secretom or doxorubicin + IFNγ stimulated hWJMSC secretome.

Fig. 5

AnnexinV-PI apoptosis assay on A549 cell line treated with hWJ-MSC seretome. There is no significant difference between a; untreated A549, b; A549 treated with hWJ-MSC secretome and c; A549 treated with IFNγ stimulated hWJ-MSC secretome.