Preliminary study on the relationship among stem cell markers, drug resistance and PI3K signaling pathway in multiple myeloma (MM) cell

BACKGROUND: This study aims to explore the mechanism of drug resistance in multiple myeloma (MM). METHODS: In this study, the possible mechanism of chemotherapeutic tolerance was preliminarily explored from two aspects: (I) the changes in cell morphology, cell cycle, cell apoptosis, stem cell markers and the signaling transduction pathway after the irradiation of RPMI-8226 cells; (II) the mechanism of enhancing chemotherapeutic sensitivity through the PI3K/AKT/mTOR signaling pathway. RESULTS: The results showed that the cell morphology and cell cycle of RPMI-8226 had been significantly changed after receiving a radiation dose of 6 Gy in the logarithmic growth phase, the sensitivity of cells to bortezomib had been decreased, the level of stem cell markers had been upregulated, and the PI3K/AKT/mTOR signaling pathway had been activated. However, blocking the PI3K/AKT/mTOR signaling pathway caused the expression of the stem cell markers of RPMI-8226 cells. In addition, the sensitivity of cells to bortezomib had been increased. CONCLUSIONS: Blocking the PI3K/AKT/mTOR might decrease the RPMI-8226 cells which survived the radiotherapy and increase the sensitivity of cells to bortezomib.