Citations

Whereas VHL inactivation is a primary event in clear cell renal cell carcinoma (ccRCC), the precise mechanism(s) of how this interacts with the secondary mutations in tumor suppressor genes, including PBRM1 , KDM5C / JARID1C , SETD2 , and/or BAP1 , remains unclear. Gene expression analyses reveal that VHL, PBRM1, or KDM5C share a common regulation of interferon response expression signature. Loss of HIF2α, PBRM1, or KDM5C in VHL-/- cells reduces the expression of interferon stimulated gene factor 3 (ISGF3), a transcription factor that regulates the interferon signature. Moreover, loss of SETD2 or BAP1 also reduces the ISGF3 level. Finally, ISGF3 is strongly tumor-suppressive in a xenograft model as its loss significantly enhances tumor growth. Conversely, reactivation of ISGF3 retards tumor growth by PBRM1-deficient ccRCC cells. Thus after VHL inactivation, HIF induces ISGF3, which is reversed by the loss of secondary tumor suppressors, suggesting that this is a key negative feedback loop in ccRCC.

Significance Cardiac arrhythmias often occur in heart failure (HF) patients, but drug therapies using selective ion channel blockers have failed clinical trials and effective drug therapies remain elusive. Here we systematically study the major ionic currents during the cardiac action potential (AP) and arrhythmogenic Ca 2+ release in postinfarction HF. We found that changes in any individual current are relatively small, and alone could mislead as to consequences. However, differential changes in multiple currents integrate to shorten AP in the infarct border zone but prolong AP in the remote zone, increasing AP repolarization inhomogeneity. Our findings help explain why single channel-blocker therapy may fail, and highlight the need to understand the integrated changes of ionic currents in treating arrhythmias in HF.

Bone atrophy and its related fragility fractures are frequent, late side effects of radiotherapy in cancer survivors and have a detrimental impact on their quality of life. In another study, we showed that parathyroid hormone 1‐34 and anti‐sclerostin antibody attenuates radiation‐induced bone damage by accelerating DNA repair in osteoblasts. DNA damage responses are partially regulated by the ubiquitin proteasome pathway. In the current study, we examined whether proteasome inhibitors have similar bone‐protective effects against radiation damage. MG132 treatment greatly reduced radiation‐induced apoptosis in cultured osteoblastic cells. This survival effect was owing to accelerated DNA repair as revealed by γH2AX foci and comet assays and to the up‐regulation of Ku70 and DNA‐dependent protein kinase, catalytic subunit, essential DNA repair proteins in the nonhomologous end‐ joining pathway. Administration of bortezomib (Bzb) reversed the loss of trabecular bone structure and strength in mice at 4 wk after focal radiation. Histomorphometry revealed that Bzb significantly increased the number of osteoblasts and activity in the irradiated area and suppressed the number and activity of osteoclasts, regardless of irradiation. Two weeks of Bzb treatment accelerated DNA repair in bone‐lining osteoblasts and thus promoted their survival. Meanwhile, it also inhibited bone marrow adiposity. Taken together, we demonstrate a novel role of proteasome inhibitors in treating radiation‐induced osteoporosis.—Chandra, A., Wang, L., Young, T., Zhong, L., Tseng, W.‐J., Levine, M. A., Cengel, K., Liu, X. S., Zhang, Y., Pignolo, R. J., Qin, L. Proteasome inhibitor bortezomib is a novel therapeutic agent for focal radiation‐induced osteoporosis. FASEB J. 32, 52‐62 (2018). www.fasebj.org

365 Background: Pancreatic ductal adenocarcinoma (PDAC) is characterized by dense stroma and connective tissue growth factor (CTGF) overexpression. Although prolonged overall survival (OS) can be achieved through resection, only approximately 15% to 20% of patients are treated with surgery. Previously, pamrevlumab (P), a fully human monoclonal antibody blocking CTGF, was combined with gemcitabine/erlotinib (G/E) in a study of advanced PDAC. P plasma levels of > 150 μg/mL and low baseline CTGF levels resulted in prolonged OS. We hypothesize that neoadjuvant (NA) treatment of LAPC with P + G/nab-paclitaxel (NP) may alter LAPC’s stroma, increase R0 resectability, and improve OS similar to that of patients resectable at presentation. Methods: LAPC subjects, confirmed by NCCN criteria and staging laparoscopy, were randomized 2:1 to G/NP ± P for 6-cycle/24-week treatment. Safety and efficacy (resection rate, OS, progression-free survival, tumor response) were assessed. Resection was performed in subjects who met protocol-defined criteria with no contraindications. Results: As of 26 Sep 2016, 25 subjects were enrolled. Of 14 subjects in Arm A (G/NP + P), 7 completed, 2 discontinued. Of 11 subjects in Arm B (G/NP), 4 completed, 4 discontinued. 6 subjects (43%) in Arm A and 4 (36%) in Arm B experienced SAEs; no P-related SAEs were reported. Out of 7 eligible Arm A subjects, 3 were not resected. Successful resection was achieved in 4 Arm A subjects (3 R0, 1 R1) and 1 Arm B subject (R0) (Table). Conclusions: The combination of G/NP + P is feasible and well-tolerated with no incremental safety signals in this study. The addition of P suggests a trend toward increased resectability among LAPC subjects. Clinical trial information: NCT02210559. [Table: see text]

Triggering receptor expressed on myeloid cells 2 (TREM2) is an innate immune receptor expressed in microglia in the brain. A soluble form of TREM2 (sTREM2) derived from proteolytic cleavage of the cell surface receptor is increased in the preclinical stages of AD and positively correlates with the amounts of total and phosphorylated tau in the cerebrospinal fluid. However, the physiological and pathological functions of sTREM2 remain unknown. Here, we show that sTREM2 promotes microglial survival in a PI3K/Akt-dependent manner and stimulates the production of inflammatory cytokines depending on NF-κB. Variants of sTREM2 carrying AD risk-associated mutations were less potent in both suppressing apoptosis and triggering inflammatory responses. Importantly, sTREM2 delivered to the hippocampi of both wild-type and Trem2-knockout mice elevated the expression of inflammatory cytokines and induced morphological changes of microglia. Collectively, these data indicate that sTREM2 triggers microglial activation inducing inflammatory responses and promoting survival. This study has implications for the pathogenesis of AD and provides insights into targeting sTREM2 pathway for AD therapy.

Objective Limited efficacy of immune checkpoint inhibitors in pancreatic ductal adenocarcinoma (PDAC) has prompted investigation into combination therapy. We hypothesised that interleukin 6 (IL-6) blockade would modulate immunological features of PDAC and enhance the efficacy of anti-programmed death-1-ligand 1 (PD-L1) checkpoint inhibitor therapy. Design Transcription profiles and IL-6 secretion from primary patient-derived pancreatic stellate cells (PSCs) were analyzed via Nanostring and immunohistochemistry, respectively. In vivo efficacy and mechanistic studies were conducted with antibodies (Abs) targeting IL-6, PD-L1, CD4 or CD8 in subcutaneous or orthotopic models using Panc02, MT5 or KPC-luc cell lines; and the aggressive, genetically engineered PDAC model (Kras LSL−G12D , Trp53 LSL−R270H , Pdx1-cre, Brca2 F/F (KPC-Brca2 mice)). Systemic and local changes in immunophenotype were measured by flow cytometry or immunohistochemical analysis. Results PSCs (n=12) demonstrated prominent IL-6 expression, which was localised to stroma of tumours. Combined IL-6 and PD-L1 blockade elicited efficacy in mice bearing subcutaneous MT5 (p<0.02) and Panc02 tumours (p=0.046), which was accompanied by increased intratumoural effector T lymphocytes (CD62L − CD44 − ). CD8-depleting but not CD4-depleting Abs abrogated the efficacy of combined IL-6 and PD-L1 blockade in mice bearing Panc02 tumours (p=0.0016). This treatment combination also elicited significant antitumour activity in mice bearing orthotopic KPC-luc tumours and limited tumour progression in KPC-Brca2 mice (p<0.001). Histological analysis revealed increased T-cell infiltration and reduced α-smooth muscle actin cells in tumours from multiple models. Finally, IL-6 and PD-L1 blockade increased overall survival in KPC-Brca2 mice compared with isotype controls (p=0.0012). Conclusions These preclinical results indicate that targeted inhibition of IL-6 may enhance the efficacy of anti-PD-L1 in PDAC.