Multitargets and Interactions of Wortmannin with MSC-Mitogenic Proteins Validate the Enhanced Antiproliferative Effect of MSCSecretome on Breast Cancer Michigan Cancer Foundation-7 Cells

Although the anticancer effect of Mesenchymal Stem Cells (MSCs) is well-reported, they play an integral role in the tumor microenvironment and contribute to tumor progression and metastasis. These events are facilitated by growth and angiogenic factors commonly released by MSCs. In the present study, we combined MSC-Conditioned Media (MSC-CM) with wortmannin, a potent PI3K/Akt-mTOR pathway inhibitor, and evaluated their anticancer effects on breast cancer cells (MCF-7). Additionally, preliminary in silico studies were conducted to allocate wortmannin cellular targets and possible molecular interactions with mitogenic factors released by MSCs. The results showed that wortmannin demonstrated an additive antiproliferative effect on breast cancer cells when it was combined with MSC-CM. This was mediated by apoptosis and necrosis, as indicated by cell membrane disintegration and staining of the nuclear DNA with ethidium bromide, nuclear condensation and DNA fragmentation observed through DAPI staining. In silico Target Fishing (TG) conducted via five databases, identified PI3K catalytic subunits (α, β, δ and γ) as common targets, along with other cellular proteins such as aromatase, arachidonate 15-lipoxygenase and M-phase inducer phosphatase 2. Moreover, wortmannin has been observed to interact with several growth factors, commonly released by MSCs, including Epidermal Growth Factors Receptor (EGFR), Transforming Growth Factor-Beta-3 (TGF- β3), and Granulocyte-Colony Stimulating Factor (G-CSF). Their docking energies were comparable to paclitaxel, a common breast cancer treatment. These preliminary investigations suggest that merging anticancer drugs with MSC-CM could be a promising cell-free chemo-regenerative therapeutic strategy against cancer cells due to their multitarget effects and interactions with MSC-derived mitogenic proteins.