Abstract:To investigate the effect of Bcl-2 small molecule inhibitor ABT-737 on autophagy apoptosis and stemness characteristics of ovarian cancer cells treated with tumor-associated macrophage (TAM)-derived exosomes (Exo). Methods Using phorbol ester (PMA) and recombinant human interleukin-4 (IL-4) to induce human peripheral blood mononuclear cells THP-1 to M2 type TAM, the expression of macrophage-related markers on the cell surface was detected by flow cytometry; The exosomes were extracted by differential centrifugation, the morphology and size distribution of exosomes were observed by transmission electron microscopy and nanoparticle tracking technology, and the expression of exosome marker proteins was detected by Western blot, Dil combined with PKH67 staining was used to detect the uptake of TAM-derived exosomes by ovarian cancer cell line SKOV3; The experimental groups were divided into control group, Exo group, and Exo+ABT-737 group. TAM-derived exosomes and ABT-737 were used to treat SKOV3 cells according to the groups, and flow cytometry was used to detect the apoptosis rate, double fluorescent mRFP-GFP-LC3 assay was used to detect the level of autophagy, Western blot was used to detect autophagy-related proteins (LC3-II/LC-3Ⅰ, Beclin-1, p62) and apoptosis-related proteins (Bax, Bcl-2, Cleaved-caspase3) expression, tumor cell spheroidization assay was used to detect cell stemness, and Western blot was used to detect the expression of cancer stem cell-related proteins (CD133, OCT4, SOX2). Results After induction by PMA and IL-4, the morphology of THP-1 cells changed, the expression ratio of M1 macrophage marker CD86 decreased while the expression ratio of M2 macrophage marker CD206 increased (P<0.05). The isolated particles are spherical vesicles with uniform size and a peak particle size of about 140 nm, the exosome marker proteins Alix, CD63, and TSG101 are clearly expressed. It is judged that the M2-type TAM source Exo was successfully isolated and can be taken up by SKOV3. Compared with the control group, the apoptosis rate of SKOV3 cells in the Exo group decreased, the fluorescent spots of GFP and mRFP decreased, the expressions of LC3-II/LC-3I, Beclin-1, Bax and Cleaved-caspase3 in the cells were all down-regulated, and p62 and Bcl-2 were all up-regulated, in addition, the number of cell spheroids increased, and the expressions of CD133, OCT4 and SOX2 were all up-regulated, the differences were statistically significant (P<0.05). Compared with the Exo group, the apoptosis rate of SKOV3 cells in the Exo+ABT-737 group increased, the fluorescent spots of GFP and mRFP also increased, the intracellular expressions of LC3-II/LC-3I, Beclin-1, Bax and Cleaved-caspase3 were all up-regulated, the expressions of p62 and Bcl-2 were down-regulated, the number of cell spheroids decreased, and the expressions of CD133, OCT4 and SOX2 were down-regulated, the differences were statistically significant (P<0.05). Conclusion ABT-737 can promote the autophagy and apoptosis of ovarian cancer cells treated with M2-type TAM-derived exosomes, and inhibit the tumor stemness characteristic of ovarian cancer