Delanzomib

Renal fibrosis is scarring and tissue hardening caused by the excess deposition of extracellular matrix proteins in response to chronic inflammation. Renal fibrosis is the primary cause of a progressive loss of renal function, and is an important therapeutic target because it ultimately leads to end-stage renal failure, which can be treated only by either dialysis or kidney transplantation. There is no effective treatment that specifically targets renal fibrosis. Myofibroblasts are known to evade apoptosis by activating molecular mechanisms in response to pro-survival biomechanical and growth factor signals from the fibrotic microenvironment. In this study, we screened and selected compounds that selectively cause cell death in myofibroblasts in vitro and studied their possible potency against renal fibrosis in a mouse model. Several proteasome inhibitors induced selective cell death in myofibroblasts differentiated from the human fibroblast cell line (MRC5). The in vivo antifibrotic effect of Delanzomib (Dz), one of the proteasome inhibitors most sensitive to myofibroblasts in vitro, was investigated in a Unilateral Ureteric Obstruction (UUO) mouse model. Treatment with Dz decreased the expression levels of the actin-alpha-2 (ACTA2) and collagen-type-1-alpha-1 (COL1A1) genes in the kidney, which are common fibrosis markers. These results suggest that Dz might be a compound that suppresses renal fibrosis by inducing selective cell death of myofibroblasts, although further investigation is required.

Medullary thyroid cancer (MTC) is a rare thyroid tumour whose management in advanced stages is challenging, despite effective therapeutic options having expanded in recent years. Proteasome inhibitors (PrIn) have shown the ability to improve patient outcomes, including survival and quality of life, in several malignancies, due to their ability to impair cell proliferation and cause apoptosis through the inhibition of the proteasome activity. Consequently, these drugs could represent a useful tool, alone or in combination with other treatments, in MTC patients.

This review aims to summarize the available in vitro and in vivo data about the role of PrIn in MTC.

We performed an extensive search for relevant data sources, including full-published articles in international online databases (PubMed, Web of Science, Scopus), preliminary reports in selected international meeting abstract repositories, and short articles published as supplements of international meetings, by using the following terms: medullary thyroid carcinoma, proteasome inhibitors, bortezomib, carfilzomib, ixazomib, delanzomib, marizomib, oprozomib, and MG132. Additionally, we conducted with the same keywords, an in-depth search in registered clinical trials repositories.

Our search revealed in vitro studies in human and murine MTC cell lines, based on the use of PrIns, both alone and in combination with other anticancer drugs, and two pertinent clinical trials.

We found a strong discrepancy between the evidence of PrIns effects in preclinical studies, and the scarcity or early interruption of clinical trials. We might speculate that difficulties in enrolling patients, as happens in other rare diseases, may have discouraged trials' implementation in favor of drugs already approved for MTC. However, given the concrete improvement in the comprehension of the molecular basis of PrIn effects in MTC, new clinical trials with accurate inclusion criteria of enrollment might be warranted, in order to ascertain whether this treatment, alone or in combination with other drugs, could indeed represent an option to enhance the therapeutic response, and to ultimately improve patients' outcome and survival.