KPNA2 enhances autophagy through activation of the non-canonical NF-κB signaling pathway, thereby promoting the induction of bortezomib resistance in multiple myeloma Free

KPNA2 enhances autophagy through activation of the non-canonical NF-κB signaling pathway, thereby promoting the induction of bortezomib resistance in multiple myeloma Background: Multiple myeloma (MM) is a malignant plasma cell disorder characterized by clonal expansion and remains incurable in clinical practice. Bortezomib (BTZ) exerts anti-tumor effects through proteasome inhibition, which disrupts cell cycle progression and induces apoptosis via suppression of the NF-κB pathway. However, increased autophagic activity diminishes MM cell responsiveness to BTZ, resulting in clinical drug resistance. Consequently, identifying novel therapeutic targets to inhibit autophagy may provide significant improvements in MM treatment efficacy.

Methods:Transcriptional profiling of KPNA2 in plasma cells from healthy donors, newly diagnosed multiple myeloma (NDMM) patients, and relapsed/refractory multiple myeloma (RRMM) patients was conducted utilizing GEO datasets. Engineered MM models with shRNA-mediated KPNA2 knockdown and KPNA2 overexpression were generated to investigate the functional significance of KPNA2 in MM pathogenesis. Cellular behaviors – including proliferation, invasion, migration, and autophagic flux – were comprehensively evaluated in MM cells with modulated KPNA2 expression. RNA sequencing identified dysregulated pathways resulting from KPNA2 knockdown. A murine xenograft model was subsequently established to evaluate the functional impact of KPNA2 on tumor proliferation dynamics and BTZ resistance in vivo.

Results: Quantitative analysis demonstrated significantly elevated KPNA2 expression in plasma cells from NDMM patients compared to healthy donors (P < 0.001), with RRMM cases exhibiting further increased expression relative to NDMM (P < 0.05). Clinically, elevated KPNA2 expression inversely correlated with overall survival in MM patients (P < 0.01). Functional studies established that KPNA2 knockdown significantly suppressed cellular proliferation, invasion, and migration in both in vitro systems and xenograft models. Critically, KPNA2 depletion sensitized MM cells to BTZ-mediated growth arrest, whereas KPNA2 overexpression conferred BTZ resistance. Combination therapy with KPNA2 silencing and BTZ synergistically enhanced cytotoxicity and apoptosis induction. Transcriptomic profiling revealed significant enrichment of autophagy-related pathways following KPNA2 depletion. Concordantly, LC3-II/LC3-I ratio quantification confirmed reduced autophagic flux upon KPNA2 knockdown, while KPNA2 overexpression augmented LC3-II conversion. Mechanistically, KPNA2-mediated reduction of BTZ sensitivity occurred through autophagy enhancement via non-canonical NF-κB pathway activation. Pharmacological inhibition of this pathway in KPNA2-overexpressing cells attenuated autophagy and restored BTZ responsiveness in both cellular and in vivo models.

Conclusion:Elevated KPNA2 expression functions as a prognostic biomarker for high-risk multiple myeloma (HR-MM) progression. Mechanistically, KPNA2 drives MM pathogenesis by activating the non-canonical NF-κB signaling pathway, thereby conferring BTZ chemoresistance. Therapeutic targeting of the KPNA2-autophagy regulatory axis represents a promising strategy to overcome KPNA2-mediated therapeutic resistance in MM.

Keywords: Multiple myeloma; Autophagy; Bortezomib; KPNA2; NF-κB