Proteasome inhibitors (PIs), used in the treatment of plasma cell myeloma (PCM), interfere with the degradation of misfolded proteins leading to activation of unfolded protein response (UPR) and cell death. However, despite initial strong antimyeloma effects, PCM cells eventually develop acquired resistance to PIs. The pleiotropic role of ʟ-glutamine (Gln) in cellular functions makes inhibition of Gln metabolism a potentially good candidate for combination therapy. Here, we show that PCM cells, both sensitive and resistant to PIs, express membrane Gln transporter (ASCT2), require extracellular Gln for survival, and are sensitive to ASCT2 inhibitors (ASCT2i). ASCT2i synergistically potentiate the cytotoxic activity of PIs by inducing apoptosis and modulating autophagy. Combination of ASCT2 inhibitor V9302 and proteasome inhibitor carfilzomib upregulates the intracellular levels of ROS and oxidative stress markers and triggers catastrophic UPR as shown by upregulated spliced Xbp1 mRNA, ATF3 and CHOP levels. Moreover, analysis of RNA sequencing revealed that the PI in combination with ASCT2i reduced the levels of Gln metabolism regulators such as MYC and NRAS. Analysis of PCM patients' data revealed that upregulated ASCT2 and other Gln metabolism regulators are associated with advanced disease stage and with PIs resistance. Altogether, we identified a potent therapeutic approach that may prevent acquired resistance to PIs and may contribute to the improvement of treatment of patients suffering from PCM.

Fatigue is the most commonly encountered symptom in patients with chronic liver disease (CLD). The resulting decrease in quality of life contributes markedly to the societal costs of fatigue. Moreover, fatigue is associated with social dysfunction, increased daytime somnolence, impaired working...

Acute-on-chronic liver failure (ACLF) is a complex and severe condition marked by multiple organ failure and high short-term mortality. Coagulopathy, a key component of ACLF, is characterized by rebalanced hemostasis with both hypo- and hypercoagulable features, increasing the risk of bleeding and thrombosis. Conventional coagulation tests, including prothrombin time (PT) and platelet count, fail to fully capture the complexity of coagulation dysfunction in ACLF. Advanced diagnostic tools, like viscoelastic tests (VETs), offer a more comprehensive assessment, yet they remain limited in evaluating endothelial dysfunction and fail to account for reduced levels of anticoagulant factors. Emerging therapeutic strategies targeting coagulopathies in ACLF hold promise, but their clinical efficacy remains unclear. A more nuanced approach to diagnosing and managing coagulopathy in ACLF is needed, incorporating advanced hemostatic profiling to better inform prognosis and guide treatment decisions.

DOI: 10.20452/pamw.16869, Published online: October 21, 2024, Authors: Artur Kośnik, Jarosław Gadomski, Paulina Walczak-Wieteska, Paweł Andruszkiewicz, Joanna Raszeja-Wyszomirska