The deubiquitinase OTUD1 regulates immunoglobulin production and proteasome inhibitor sensitivity in multiple myeloma.

Serum monoclonal immunoglobulin (Ig) is the main diagnostic factor for patients with multiple myeloma (MM), however its prognostic potential remains unclear. On a large MM patient cohort (n = 4146), we observe no correlation between serum Ig levels and patient survival, while amount of intracellular Ig has a strong predictive effect. Focused CRISPR screen, transcriptional and proteomic analysis identify deubiquitinase OTUD1 as a critical mediator of Ig synthesis, proteasome inhibitor sensitivity and tumor burden in MM. Mechanistically, OTUD1 deubiquitinates peroxiredoxin 4 (PRDX4), protecting it from endoplasmic reticulum (ER)-associated degradation. In turn, PRDX4 facilitates Ig production which coincides with the accumulation of unfolded proteins and higher ER stress. The elevated load on proteasome ultimately potentiates myeloma response to proteasome inhibitors providing a window for a rational therapy. Collectively, our findings support the significance of the Ig production machinery as a biomarker and target in the combinatory treatment of MM patients.

A Review of Molecular and Genetic Diagnostics of Myeloid Malignancies with Emphasis on Diagnostics in Bosnia and Herzegovina.

Here we describe the major genetic and genomic aberrations found in myeloid malignancies and how those markers are used in patients' diagnosis, prognosis, and targeted treatment. In Bosnia and Herzegovina, cytogenetic and molecular diagnostics for myeloid malignancies have been established and continually improved since 2005. We report the current state of available diagnostic tools for myeloid malignancies in Bosnia and Herzegovina. Myeloid malignancies are a heterogeneous group of clonal blood diseases characterized by defects in hematopoietic stem cells and myeloid progenitors that lead to abnormal proliferation, differentiation, localization, and self-renewal. Most common myeloid malignancies include myeloproliferative neoplasms (MPNs), myelodysplastic syndrome (MDS), and acute myeloid leukemia (AML). Molecular diagnostics of myeloid malignancies have significantly expanded in the last decade with new genetic and genomic markers for diagnosis, prognosis, and treatment. CONCLUSION: In the last decade, several new genomic markers important for patient diagnosis, prognosis, and therapy have been discovered that need to be implemented in routine molecular diagnostics not only in developed nations but also in developing nations such as Bosnia and Herzegovina.

Intercellular Mitochondrial Transfer in the Tumor Microenvironment.

Cell-to-cell communication is a fundamental process in every multicellular organism. In addition to membrane-bound and released factors, the sharing of cytosolic components represents a new, poorly explored signaling route. An extraordinary example of this communication channel is the direct transport of mitochondria between cells. In this review, we discuss how intercellular mitochondrial transfer can be used by cancer cells to sustain their high metabolic requirements and promote drug resistance and describe relevant molecular players in the context of current and future cancer therapy.