Dual Knockdown of Musashi RNA-Binding Proteins MSI-1 and MSI-2 Attenuates Putative Cancer Stem Cell Characteristics and Therapy Resistance in Ovarian Cancer Cells

• Published in: International journal of molecular sciences 2021-10, Vol.22 (21), p.11502
• Main Authors: Löblein, Maria T, Falke, Isabel, Eich, Hans Theodor, Greve, Burkhard, Götte, Martin, Troschel, Fabian M
• Format: Article
• Language: English
• Subjects: 1-Pyrroline-5-Carboxylate Dehydrogenase - genetics; Apoptosis; Apoptosis - genetics; Binding; cancer stem cell; Cancer therapies; Carcinoma, Ovarian Epithelial - genetics; Carcinoma, Ovarian Epithelial - pathology; Cell cycle; Cell Cycle - genetics; Cell Line, Tumor; Cell Proliferation - genetics; Chemoresistance; Chemotherapy; Cyclin-Dependent Kinase Inhibitor p21 - genetics; Down-Regulation - genetics; Drug Resistance, Neoplasm - genetics; Female; Flow cytometry; Gene expression; Gene Expression Regulation, Neoplastic - genetics; Gene silencing; Genes; Humans; Investigations; Irradiation; Metabolism; Musashi; Myc protein; Neoplastic Stem Cells - pathology; Nerve Tissue Proteins - genetics; notch; Ovarian cancer; Ovarian Neoplasms - genetics; Ovarian Neoplasms - pathology; Ovarian Neoplasms - therapy; Ovary - pathology; Polymerase chain reaction; Post-irradiation; Protein expression; Proteins; Proto-Oncogene Proteins c-myc - genetics; Radiation; Radiation Tolerance - genetics; Radioresistance; Receptors, Notch - genetics; RNA Interference; RNA, Small Interfering - genetics; RNA-binding protein; RNA-Binding Proteins - genetics; siRNA; Stem cells; therapy resistance; Tumors; Western blotting
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms222111502

In ovarian cancer, therapy resistance mechanisms complicate cancer cell eradication. Targeting Musashi RNA-binding proteins (MSI) may increase therapeutic efficacy. Database analyses were performed to identify gene expression associations between MSI proteins and key therapy resistance and cancer stem cell (CSC) genes. Then, ovarian cancer cells were subjected to siRNA-based dual knockdown of MSI-1 and MSI-2. CSC and cell cycle gene expression was investigated using quantitative polymerase chain reaction (qPCR), western blots, and flow cytometry. Metabolic activity and chemoresistance were assessed by MTT assay. Clonogenic assays were used to quantify cell survival post-irradiation. Database analyses demonstrated positive associations between MSI proteins and putative CSC markers NOTCH, MYC, and ALDH4A1 and negative associations with NOTCH inhibitor NUMB. MSI-2 expression was negatively associated with the apoptosis regulator p21. MSI-1 and MSI-2 were positively correlated, informing subsequent dual knockdown experiments. After MSI silencing, CSC genes were downregulated, while cell cycle progression was reduced. Metabolic activity was decreased in some cancer cells. Both chemo- and radioresistance were reduced after dual knockdown, suggesting therapeutic potential. Dual knockdown of MSI proteins is a promising venue to impede tumor growth and sensitize ovarian cancer cells to irradiation and chemotherapy.