REV1 Inhibition Enhances Radioresistance and Autophagy

SIMPLE SUMMARY: Cancer resistance to therapy continues to be the biggest challenge in treating patients. Targeting the mutagenic translesion synthesis (TLS) polymerase REV1 was previously shown to sensitize cancer cells to chemotherapy. In this study, we tested the ability of REV1 inhibitors to radiation therapy and observed a lack of radiosensitization. In addition, we observed REV1 inhibition to trigger an autophagy stress response. Because reduction of REV1 triggered autophagy and failed to radiosensitize cells, we hypothesize REV1 expression dynamics might link cancer cell response to radiation treatment through the potential induction of autophagy. ABSTRACT: Cancer therapy resistance is a persistent clinical challenge. Recently, inhibition of the mutagenic translesion synthesis (TLS) protein REV1 was shown to enhance tumor cell response to chemotherapy by triggering senescence hallmarks. These observations suggest REV1’s important role in determining cancer cell response to chemotherapy. Whether REV1 inhibition would similarly sensitize cancer cells to radiation treatment is unknown. This study reports a lack of radiosensitization in response to REV1 inhibition by small molecule inhibitors in ionizing radiation-exposed cancer cells. Instead, REV1 inhibition unexpectedly triggers autophagy, which is a known biomarker of radioresistance. We report a possible role of the REV1 TLS protein in determining cancer treatment outcomes depending upon the type of DNA damage inflicted. Furthermore, we discover that REV1 inhibition directly triggers autophagy, an uncharacterized REV1 phenotype, with a significant bearing on cancer treatment regimens

The movement and physiological demands of international and regional men’s touch rugby matches

This study compared the internal and external match demands imposed on international and regional standard male touch rugby players. The study adopted a cohort design with independent groups. Twelve international players (mean age 27.8 ± 6.2 y, body mass 72.8 ± 3.7 kg, stature 174.5 ± 5.4 cm) and nine regional players (mean age 25.5 ± 5.5 y, body mass 74.2 ± 7 kg, stature 174.1 ± 7 cm) were analysed during nine competitive matches from the 2013 season. Movement demands were measured using a 5 Hz global positioning system (GPS), alongside heart rate and session rating of perceived exertion (s-RPE) to quantify internal load. Total distance covered by international players was lower than regional players (2265.8 ± 562.3 cf. 2970 ± 558.9 m, p14 km·h) was not different between groups (p>0.05), but relative high speed running (39.3 ± 12.0 cf. 26.0 ± 13.6 m·min) was higher for international players. Regional players performed more absolute low speed activity (≤14 km·h) than international players (p0.05). Very high speed running (>20 km·h) distance, bout number and frequency, peak and average speed were all greater in international players (p<0.05). Higher average heart rate, summated heart rate and s-RPE (p<0.05) indicated higher internal loads during matches for regional players. These data indicate that performance in men's touch rugby is characterised by more relative high speed running and better repeated sprint capacities in higher standard players

Molecular basis for increased susceptibility of Indigenous North Americans to seropositive rheumatoid arthritis

Objective The pathogenetic mechanisms by which HLA-DRB1 alleles are associated with anticitrullinated peptide antibody (ACPA)-positive rheumatoid arthritis (RA) are incompletely understood. RA high-risk HLA-DRB1 alleles are known to share a common motif, the ‘shared susceptibility epitope (SE)’. Here, the electropositive P4 pocket of HLA-DRB1 accommodates self-peptide residues containing citrulline but not arginine. HLA-DRB1 His/Phe13β stratifies with ACPA-positive RA, while His13βSer polymorphisms stratify with ACPA-negative RA and RA protection. Indigenous North American (INA) populations have high risk of early-onset ACPA-positive RA, whereby HLA-DRB1*04:04 and HLA-DRB1*14:02 are implicated as risk factors for RA in INA. However, HLA-DRB1*14:02 has a His13βSer polymorphism. Therefore, we aimed to verify this association and determine its molecular mechanism. Methods HLA genotype was compared in 344 INA patients with RA and 352 controls. Structures of HLA-DRB1*1402-class II loaded with vimentin-64Arg59-71, vimentin-64Cit59-71 and fibrinogen β−74Cit69-81 were solved using X-ray crystallography. Vimentin-64Cit59-71-specific and vimentin59-71-specific CD4+ T cells were characterised by flow cytometry using peptide-histocompatibility leukocyte antigen (pHLA) tetramers. After sorting of antigen-specific T cells, TCRα and β-chains were analysed using multiplex, nested PCR and sequencing. Results ACPA+ RA in INA was independently associated with HLA-DRB1*14:02. Consequent to the His13βSer polymorphism and altered P4 pocket of HLA-DRB1*14:02, both citrulline and arginine were accommodated in opposite orientations. Oligoclonal autoreactive CD4+ effector T cells reactive with both citrulline and arginine forms of vimentin59-71 were observed in patients with HLA-DRB1*14:02+ RA and at-risk ACPA- first-degree relatives. HLA-DRB1*14:02-vimentin59-71-specific and HLA-DRB1*14:02-vimentin-64Cit59-71-specific CD4+ memory T cells were phenotypically distinct populations. Conclusion HLA-DRB1*14:02 broadens the capacity for citrullinated and native self-peptide presentation and T cell expansion, increasing risk of ACPA+ RA

Updates on radiotherapy-immunotherapy combinations: Proceedings of 6(th) annual ImmunoRad conference

Focal radiation therapy (RT) has attracted considerable attention as a combinatorial partner for immunotherapy (IT), largely reflecting a well-defined, predictable safety profile and at least some potential for immunostimulation. However, only a few RT-IT combinations have been tested successfully in patients with cancer, highlighting the urgent need for an improved understanding of the interaction between RT and IT in both preclinical and clinical scenarios. Every year since 2016, ImmunoRad gathers experts working at the interface between RT and IT to provide a forum for education and discussion, with the ultimate goal of fostering progress in the field at both preclinical and clinical levels. Here, we summarize the key concepts and findings presented at the Sixth Annual ImmunoRad conference

Implications of the CALM-AF10 oncogenic fusion protein on Wnt signaling in leukemia

Hematopoiesis is the complex differentiation process involving the formation of all blood cells from a common progenitor; the hematopoietic stem cell. Errors in this process can lead to acute leukemia, or a rapid accumulation of immature blood cells which hinders proper immune function. While survival rates of this devastating disease have increased dramatically over the last several decades, certain cytogenetic abnormalities remain risk factors for treatment resistance and relapse. One of these abnormalities is a chromosomal translocation involving the transcription factor, AF10 Mix-Lineage Leukemia, Translocated to, 10 (MLLT 10, referred to as AF10) is involved in several oncogenic translocations involved in high-risk leukemia. Functionally characterized as a cofactor of the histone methyltransferase, DOT1L, the extent of AF10 function has not been determined. Examination of AF10 structure and interaction partner, b-Catenin, has lead us to develop a hypothesis regarding the role of AF10 in canonical Wnt signaling. Wnt is a highly complex signaling pathway which plays roles in cell fate determination and self-renewal, and is thought to be vital for the onset and progression of leukemia. We hypothesize that the AF10 fusion protein, CALM-AF10, impacts the normal AF10-b-Catenin interaction, and acts to dysregulate Wnt signaling as a mechanism for promoting leukemia. We have developed a luciferase reporter system in HEK293T cells by which to test this hypothesis, and utilize immunoprecipitation to investigate the interaction between CALM-AF10 and b-Catenin. We determine through the work of this thesis, that CALM-AF10 upregulates Wnt signaling in a manner independent of an interaction with b-Catenin

Unraveling the Role of AF10 in Acute Leukemia

Non-random chromosomal translocations represent a common cytogenetic abnormality in acute leukemia, and understanding the functional alterations of these translocations is critical for developing effective treatment for patients. Mixed Lineage Leukemia Translocated to 10 (AF10) is found translocated in-frame with up to seven different genes, all leading to the development of acute myeloid or acute lymphoid leukemia (AML or ALL). While the role of AF10 is broadly known to be a cofactor of the histone methyltransferase, DOT1L, the extent of its function in leukemia remains understudied. As previously shown in colorectal cancer cells, AF10 directly interacts with b-catenin and is required for proper Wnt/b-catenin target gene expression. Activation of the canonical Wnt/b-catenin pathway, normally inactivated after hematopoietic differentiation, is critical for the development of myeloid and lymphoid leukemic stem cells. It is not known how perturbed AF10 alters the Wnt transcriptional response in leukemia cells, but uncovering these consequences is vital for a better understanding of the mechanisms driving AF10 translocated leukemogenesis. We have confirmed the interaction of AF10 and b-catenin in leukemic cells, and will investigate the role of AF10 and AF10 fusion proteins in Wnt signaling in leukemia

Welcome and Opening Remarks Work/Life Conflict in the Legal Profession

At a symposium sponsored by the Women’s Rights Law Reporter, Professor Tanya Hernandez introduces the keynote speaker, Professor Joan Williams, a law professor at the American Law School, Washington College of Law in Washington,D.C. where she teaches Property, Women\u27s Legal History, Feminist Jurist Prudence, and a Jurist Prudence seminar. The topic of the symposium is Work/Life Conflict in the Legal Profession