Effects of long-term exposure to MST-312 on lung cancer cells tumorigenesis: Role of SHH/GLI-1 axis

Enhanced induction of apoptosis in chronic myeloid leukemia cells through synergistic effect of telomerase inhibitor MST-312 and imatinib

BACKGROUND

Chronic Myeloid Leukemia (CML), accounting for 15-20% of adult leukemia cases, is marked by the Philadelphia chromosome, resulting from the t(9;22)(q34;q11) translocation. This leads to uncontrolled cell proliferation and survival. Imatinib therapy lowers BCR-ABL levels, influencing telomere-associated proteins and increasing telomerase accessibility, indirectly boosting its activity. This study investigates the effects of MST-312 and imatinib, both individually and combined, on a CML cell line.

METHODS

The K562 cells were subjected to different doses of MST-312 and imatinib, including four combination concentrations. Cell viability and metabolic activity were measured using trypan blue and MTT assays at 24-, 36-, and 48-h post-treatment. Flow cytometry (AnnexinV/PI) assessed cell apoptosis after 36 h of treatment with MST-312 and imatinib, both individually and in combination. The expression levels of Bax, Bcl-2, hTERT, P21, P53, and c-Myc were determined via qRT-PCR.

RESULTS

Both MST-312 and imatinib independently reduced cell viability in a dose- and time-dependent manner. Their combination further decreased cell viability compared to monotherapy. Treatment of K562 cells with MST-312 and imatinib for 36 h increased Bax expression and the Bax/Bcl-2 ratio while decreasing Bcl-2 expression. Combined treatment significantly reduced hTERT ansd P21 gene expression compared to imatinib alone.

CONCLUSIONS

The combination of MST-312 and imatinib shows potential as a CML therapy. However, further research and clinical trials are necessary to validate these findings and determine their clinical relevance.

Combinatorial targeting of telomerase and DNA-PK induces synergistic apoptotic effects against Pre-B acute lymphoblastic leukemia cells

BACKGROUND

Due to the high demand for novel approaches for leukemia-targeted therapy, this study investigates the impact of DNA-PK inhibitor NU7441 on the sensitivity of pre-B ALL cells to the telomerase inhibitor MST-312.

METHODS

The study involved NALM-6 cells treated with MST-312 and NU7441, assessing their viability and metabolic activity using trypan blue and MTT assays. The study also evaluated apoptosis, gene expression changes, and DNA damage using flow cytometry, qRT-PCR, and micronucleus assays. The binding energy of MST-312 in the active site of telomerase was calculated using molecular docking.

RESULTS

The study's findings revealed a synergistic decline in both cell viability and metabolic activity in NALM-6 cells when exposed to the combined treatment of MST-312 and NU7441, and this decrease occurred without any adverse effects on healthy PBMC cells. Furthermore, the combination treatment exhibited a significantly higher induction of apoptosis than treatment with MST-312 alone, as observed through flow cytometry assay. qRT-PCR analysis revealed that this enhanced apoptosis was associated with a notable downregulation of Bcl-2 expression and an upregulation of Bax gene expression. Moreover, the combination therapy decreased expression levels of hTERT and c-Myc genes. The micronucleus assay indicated that the combination treatment increased DNA damage in NALM-6 cells. Also, a good conformation between MST-312 and the active site of telomerase was revealed by docking data.

CONCLUSIONS

The study suggests that simultaneous inhibition of telomerase and DNA-PK in pre-B ALL presents a novel targeted therapy approach.