Investigating the therapeutic effect of metformin on melanoma cancer stem cells using optical microscopy

Cancer stem cells (CSCs) are neoplastic cells that possess certain stem cell properties and are increasingly recognized as pivotal contributors to cancer metastasis, recurrence, and therapy resistance. Recent studies have demonstrated that metformin, a medication for type 2 diabetes, can inhibit the proliferation of CSCs. Malignant melanoma, which harbors CSCs, serves as a valuable model for evaluating cancer therapies and characterizing CSCs. This study assessed the impact of metformin (0-500<i>µ</i>g ml^-1) on melanoma CSCs by employing<i>in vitro</i>three-dimensional (3D) cell cultures and optical microscopy. Our findings revealed that higher concentrations (24 mM) of metformin corresponded to a reduced number of cell spheres, consistent with results reported by other research groups. These observations suggest that optical microscopy is a viable technique for monitoring the short-term effects of metformin on melanoma CSCs<i>in vitro</i>.