Therapy for relapsed multiple myeloma

Metabolomics approach reveals key plasma biomarkers in multiple myeloma for diagnosis, staging, and prognosis

BACKGROUND

Multiple myeloma (MM) is the most aggressive and prevalent primary malignant tumor within the blood system, and can be classified into grades RISS-I, II, and III. High-grade tumors are associated with decreased survival rates and increased recurrence rates. To better understand metabolic disorders and expand the potential targets for MM, we conducted large-scale untargeted metabolomics on plasma samples from MM patients and healthy controls (HC).

METHODS

Our study included 33 HC, 38 newly diagnosed MM patients (NDMM) categorized into three RISS grades (grade I: n = 5; grade II: n = 19; grade III: n = 8), and 92 MM patients post-targeted therapy with bortezomib-based regimens. Simultaneously, MM cell lines were employed for validation studies. Metabolites were analyzed and identified using ultra high liquid chromatography coupled with Q Orbitrap mass spectrometry (UPLC-HRMS), followed by verification through a self-built database.

RESULTS

Compared with HC participants, a total of 70 metabolites were identified as undergoing significant changes in NDMM. These metabolites were significantly enriched in citrate cycle, choline metabolism, glycerophospholipid metabolism, and sphingolipid metabolism, etc. Notably, a panel of circulating plasma metabolite biomarkers, including lactic acid and leucine, has emerged not only as diagnostic indicators but also as valuable tools for tumor surveillance, aiding in the assessment of disease stage and prognostic evaluation. Moreover, 14 differential metabolites were identified in both MM cell lines and MM patients. Among these, intracellular levels of lactate and leucine significantly decreased in vitro, aligning with the plasma results.

CONCLUSION

Our findings on key metabolites and metabolic pathways provide novel insights into the exploration of diagnostic and therapeutic targets for MM. A prospective study is essential to validate these discoveries for future MM patient care.

Cyclopamine sensitizes multiple myeloma cells to circularly permuted TRAIL-induced apoptosis

Tumor necrosis factor related apoptosis inducing ligand (TRAIL) is a promising anti-myeloma drug prototype. The aim of the present study was to investigate the synergistic effects of cyclopamine and circularly permuted TRAIL (CPT) on the proliferation and apoptosis of multiple myeloma cells. The results showed that the inhibitory effects of cyclopamine on the proliferation of human myeloma RPMI-8226 and SKO-007 cells were weak. RPMI-8226 cells were sensitive to CPT; however, the proliferation of SKO-007 cells was not effectively inhibited by CPT. SKO-007 cells were thus considered resistant to cyclopamine and CPT and used for subsequent experiments. Treatment with a combination of cyclopamine and CPT significantly inhibited cell proliferation. Moreover, the Q value showed that cyclopamine combined with CPT could synergistically inhibit the proliferation of SKO-007 cells. Cyclopamine increased CPT-induced apoptosis in the SKO-007 cells and exhibited a synergistic induction of apoptosis when combined with CPT. Moreover, the combination of cyclopamine and CPT decreased the ratio of myeloma stem cells. Quantitative PCR showed that cyclopamine decreased the mRNA expression levels of GLI1/GLI2/GLI3 and increased the expression levels of death receptor 4. In conclusion, the present study showed that a combination of cyclopamine and CPT exhibited synergistic effects on the inhibition of proliferation and induction of apoptosis in myeloma cells.