Nonhematopoietic IRAK1 drives arthritis via neutrophil chemoattractants

New molecular targets in the treatment of rheumatoid arthritis

PURPOSE OF REVIEW

This review will discuss selected emerging molecular targets and associated potential therapeutic agents for rheumatoid arthritis (RA)-directed treatment.

RECENT FINDINGS

Agents in active development for RA treatment include those targeted to CD40 and CD40 ligand, programmed death protein 1 (PD-1), and granulocyte-macrophage colony-stimulating factor (GM-CSF). Several other molecules with a strong theoretical role in RA pathogenesis and/or demonstrated efficacy in other autoimmune diseases are also being evaluated as potential drug targets in preclinical or translational studies in RA. These targets include interleukin 1 receptor associated kinases 1 and 4 (IRAK1, IRAK4), tyrosine kinase 2 (Tyk2), bradykinin receptor 1 (B1R), OX40 and OX40 ligand.

SUMMARY

Identification of molecular targets for RA treatment remains an active area of investigation, with multiple therapeutic agents in clinical and preclinical development.

Role of HDAC6-STAT3 in immunomodulatory pathways in Colorectal cancer cells

Colorectal cancer (CRC) is one of the most common malignant neoplasms and the second leading cause of death from tumors worldwide. Therefore, there is a great need to study new therapeutical strategies, such as effective immunotherapies against these malignancies. Unfortunately, many CRC patients do not respond to current standard immunotherapies, making it necessary to search for adjuvant treatments. Histone deacetylase 6 (HDAC6) is involved in several processes, including immune response and tumor progression. Specifically, it has been observed that HDAC6 is required to activate the Signal Transducer and Activator of Transcription 3 (STAT3), a transcription factor involved in immunogenicity, by activating different genes in these pathways, such as PD-L1. Over-expression of immunosuppressive pathways in cancer cells deregulates T-cell activation. Therefore, we focused on the pharmacological inhibition of HDAC6 in CRC cells because of its potential as an adjuvant to avoid immunotolerance in immunotherapy. We investigated whether HDAC6 inhibitors (HDAC6is), such as Nexturastat A (NextA), affected STAT3 activation in CRC cells. First, we found that NextA is less cytotoxic than the non-selective HDACis panobinostat. Then, NextA modified STAT3 and decreased the mRNA and protein expression levels of PD-L1. Importantly, transcriptomic analysis showed that NextA treatment affected the expression of critical genes involved in immunomodulatory pathways in CRC malignancies. These results suggest that treatments with NextA reduce the functionality of STAT3 in CRC cells, impacting the expression of immunomodulatory genes involved in the inflammatory and immune responses. Therefore, targeting HDAC6 may represent an interesting adjuvant strategy in combination with immunotherapy.