Interplay between proteasome inhibitors and NF-κB pathway in leukemia and lymphoma: a comprehensive review on challenges ahead of proteasome inhibitors.

The current scientific literature has extensively explored the potential role of proteasome inhibitors (PIs) in the NF-κB pathway of leukemia and lymphoma. The ubiquitin-proteasome system (UPS) is a critical component in regulating protein degradation in eukaryotic cells. PIs, such as BTZ, are used to target the 26S proteasome in hematologic malignancies, resulting in the prevention of the degradation of tumor suppressor proteins, the activation of intrinsic mitochondrial-dependent cell death, and the inhibition of the NF-κB signaling pathway. NF-κB is a transcription factor that plays a critical role in the regulation of apoptosis, cell proliferation, differentiation, inflammation, angiogenesis, and tumor migration. Despite the successful use of PIs in various hematologic malignancies, there are limitations such as resistant to these inhibitors. Some reports suggest that PIs can induce NF-κB activation, which increases the survival of malignant cells. This article discusses the various aspects of PIs' effects on the NF-κB pathway and their limitations. Video Abstract.

Long-term Effects of Regular Whole Blood Donation on Peripheral Blood CD34+ Cells Population with using Leukoreduction Filters.

Background & Objective: Trapped cell population in leukoreduction filters (LRFs) contains such a significant number of CD34+ hematopoietic stem cells that can be recovered to be used in research studies. Methods: Samples (n=20) were obtained from 10 first-time donors and 10 regular blood donors with more than 30 times blood donation. After separating leukocytes from LRFs by backflushing, total leukocyte number and differential count were determined in both groups using an automated haemocytometer. Then cell viability and CD34+ cell quantification were assessed using 7- amino-actinomycin D and fluorescent-labeled monoclonal antibodies using flow cytometry, respectively. Results: Total leukocyte count was 665±164.92×106 in the first-time blood donors and 883±233.89×106 in the regular donors, which were not significantly different (P=0.08). While the number of CD34+ cells was significantly reduced in the regular donors compared to the first-time donors (0.58±0.20×106/µL vs. 0.36±0.22×106/µL; P=0.034). There was no significant difference in terms of absolute neutrophil count (10.58±3.66×06 vs. 13.17±6.45×106/µL; P=0.349), lymphocytes (7.75±3.11×106 vs. 10.38±3.77×106 /µL; P=0.917), and monocytes (2.31±0.88×106 vs. 2.59±1.09×106/µL; P=0.591) between the first-time and regular donor groups, respectively. Based on the correlation coefficients, the participants' age had no significant effect on these variables. Conclusion: The results of this study depicted that regular blood donation reduces the number of CD34+ cells in the peripheral blood (PB) of regular donors while it has no significant effect on the ratio of myeloid to lymphoid cells of the two groups.

A Role for the Bone Marrow Microenvironment in Drug Resistance of Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a heterogeneous disease with a poor prognosis and remarkable resistance to chemotherapeutic agents. Understanding resistance mechanisms against currently available drugs helps to recognize the therapeutic obstacles. Various mechanisms of resistance to chemotherapy or targeted inhibitors have been described for AML cells, including a role for the bone marrow niche in both the initiation and persistence of the disease, and in drug resistance of the leukemic stem cell (LSC) population. The BM niche supports LSC survival through direct and indirect interactions among the stromal cells, hematopoietic stem/progenitor cells, and leukemic cells. Additionally, the BM niche mediates changes in metabolic and signal pathway activation due to the acquisition of new mutations or selection and expansion of a minor clone. This review briefly discusses the role of the BM microenvironment and metabolic pathways in resistance to therapy, as discovered through AML clinical studies or cell line and animal models.