Öksüzoğlu, EmineKozalak, Gül2021-05-252021-05-252021https:/dx.doi.org/10.1515/tjb-2019-0521https://hdl.handle.net/20.500.12451/7966Background: Multiple myeloma (MM), a malignancy of plasma cells, is the second most prevalent hematological cancer. Bortezomib is the most effective chemotherapeutic drug used in treatment. However, drug-resistance prevents success of chemotherapy. One of the factors causing drug-resistance is dysfunction of apoptotic-pathways. This study aimed to evaluate the relationship between expression levels of Bcl-2, Bax, caspase-3 and p-53 genes involved in apoptosis and the development of bortezomib-resistance in MM cell lines. Materials and methods: Multiple myeloma KMS20 (bortezomib-resistant) and KMS28 (bortezomib-sensitive) cell lines were used. 3-[4,5-Dimethylthiazol-2-yl] 1-2,5-diphenylte-trazolium bromide (MTT) assay was performed to determine IC50 values of bortezomib. RNAs were isolated from bortezomib-treated cell lines, followed by cDNA synthesis. Expression levels of the genes were analyzed by using q-Realtime-PCR. Results: As a result, Bcl-2/Bax ratio was higher in KMS20 (resistant) cells than in KMS28 (sensitive) cells. Expression of caspase-3 decreased in KMS20-cells, whereas increased in KMS28-cells. The results indicate that apoptosis was suppressed in resistant cells. Conclusion: These findings will enable us to understand the molecular mechanisms leading to drug-resistance in MM cells and to develop new methods to prevent the resistance. Consequently, preventing the development of bortezomib resistance by eliminating the factors which suppress apoptosis may be a new hope for MM treatment.eninfo:eu-repo/semantics/openAccessMultiple MyelomaBortezomibDrug-ResistanceApoptosisBcI-2/BaxCancerArticle461636910.1515/tjb-2019-0521Q3WOS:000625120300010Q4