Author contributions K.Y. and A.V. performed the majority of experiments and wrote the manuscript. J.Y. assisted with cloning and performed the proximity biotinylation and ubiquitylation experiments. D.E.B. and A.S.W.S. assisted with animal studies. S.G. performed immunofluorescence and analysis of patient PDAC specimens. M.K. assisted with the analysis of flow cytometry data and RNA-seq data. S.M. assisted with immunoblotting and preparing shRNAs. E.Y.L. and S.J.P. cloned fluorescent constructs. K.W.W. and G.E.K. provided PDAC patient specimens and analysis. J.D. provided GFP-NBR1 and GFP-NBR1 dUBA constructs. R.S.B. assisted with transcriptome data analysis. J.D.M. and J.A.P. performed proteomics analysis. D.T.F. provided intellectual feedback and support. R.M.P. and A.C.K. conceived the project, supervised the research, and wrote and edited the paper.Competing interests A.C.K. has financial interests in Vescor Therapeutics, LLC. A.C.K. is an inventor on patents pertaining to KRAS regulated metabolic pathways, redox control pathways in pancreatic cancer, targeting GOT1 as a therapeutic approach, and the autophagic control of iron metabolism. A.

SUMMARY The mitochondrial protein MAVS (also known as IPS-1, VISA, CARDIF) interacts with RLR (RIG-I-like receptors) to induce type 1 interferon (IFN-I) during viral infection. NLRX1 is a mitochondrial NLR (nucleotide-binding, leucine-rich repeats containing) protein that attenuates MAVS-RLR signaling. Using Nlrx1−/− cells we confirmed NLRX1 attenuated IFN-I production, but additionally promoted autophagy during viral infection. This dual function of NLRX1 paralleled the previously described functions of the autophagy-related proteins Atg5-Atg12, but NLRX1 did not associate with Atg5-Atg12. High throughput quantitative mass spectrometry and endogenous protein-protein interaction revealed an NLRX1-interacting partner, mitochondrial Tu translation elongation factor (TUFM). TUFM interacted with Atg5-Atg12 and Atg16L1, and has similar functions as NLRX1 by inhibiting RLR-induced IFN-I but promoting autophagy. In the absence of NLRX1, increased IFN-I and decreased autophagy provide an advantage for host defense against vesicular stomatitis virus. This study establishes a link between an NLR protein and the viral-induced autophagic machinery via an intermediary partner, TUFM.

Kaposi sarcoma-associated herpesvirus (KSHV) is a double-stranded DNA herpesvirus belonging to the gammaherpesvirinae subfamily. KSHV has been associated with the development of three neoplastic diseases: Kaposi sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman disease (MCD). In this review, we discuss the three KSHV-associated malignancies, KSHV genome, latent and lytic aspects of the viral lifecycle, putative viral oncogenes, as well as therapeutic regimens used for the treatment of KS, PEL, and MCD.

Aims The pathological features and diagnostic reliability of crypt cell atypia (CCA) arising in inflammatory bowel disease (IBD) and its clinical significance are unknown. Methods and results DNA flow cytometry (FCM) was performed on 14 colon biopsies of CCA from seven IBD patients (male‐to‐female ratio, 5:2; mean age, 53 years; mean IBD duration, 15 years) using paraffin‐embedded tissue. Seven gastrointestinal pathologists were asked to diagnose each biopsy as negative for dysplasia (NEG), indefinite for dysplasia (IND), low‐grade dysplasia (LGD) or high‐grade dysplasia (HGD) by morphology alone, then again with knowledge of FCM results. Aneuploidy was detected in all 14 biopsies, and five of eight biopsies (63%) also showed strong and diffuse nuclear staining for p53 in the areas of CCA. Six (86%) patients developed HGD (n = 5) or adenocarcinoma (n = 1) in the same colonic segment where CCA had been diagnosed within a mean follow‐up time of 27 months. No follow‐up information was available in the remaining one patient. When diagnoses were grouped as NEG or ‘atypical’ (including IND, LGD or HGD), the overall agreement rate of 76% (kappa = 0.51) based on morphology alone improved to 90% (kappa = 0.81) with knowledge of FCM results. Even when categorised as NEG or dysplasia (LGD or HGD) with each of the IND diagnoses reclassified into three categories (NEG, LGD or HGD) based on the degree of suspicion for dysplasia, the overall agreement rate of 63% (kappa = 0.25) based on morphology alone improved to 73% (kappa = 0.46) with knowledge of FCM results. However, when grouped as NEG, LGD or HGD, the overall agreement rate was less than 40% (kappa < 0.09) regardless of knowledge of FCM results. Conclusions The presence of aneuploidy, p53 positivity and development of HGD or adenocarcinoma on follow‐up indicate that CCA likely represents a dysplastic lesion (at least LGD) and is a histological marker of neoplastic progression. Although the grading of CCA, largely based on cytological abnormalities, is subject to significant interobserver variability, CCA can be histologically identified and should lead to a recommendation of increased endoscopic surveillance, especially if aneuploidy is detected.

Heat-shock protein 90 (Hsp90) inhibitors exhibit activity against human cancers. We evaluated a series of new, oral bioavailable, chemically diverse Hsp90 inhibitors (PU-H71, AUY922, BIIB021, NVP-BEP800) against Kaposi sarcoma (KS). All Hsp90 inhibitors exhibited nanomolar EC50 in culture and AUY922 reduced tumor burden in a xenograft model of KS. KS is associated with KS-associated herpesvirus (KSHV). We identified the viral latency associated nuclear antigen (LANA) as a novel client protein of Hsp90 and demonstrate that the Hsp90 inhibitors diminish the level of LANA through proteasomal degradation. These Hsp90 inhibitors also downregulated EphA2 and ephrin-B2 protein levels. LANA is essential for viral maintenance and EphA2 has recently been shown to facilitate KSHV infection; which in turn feeds latent persistence. Further, both molecules are required for KS tumor formation and both were downregulated in response to Hsp90 inhibitors. This provides a rationale for clinical testing of Hsp90 inhibitors in KSHV-associated cancers and in the eradication of latent KSHV reservoirs.

Kaposi sarcoma-associated herpesvirus (KSHV) is a member of the gammaherpesvirus family. It is the etiological agent of three different human cancers, Kaposi sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman disease (MCD). The far left-end of the KSHV genome encodes a unique transmembrane glycoprotein called K1. K1 possesses the ability to transform rodent fibroblasts and block apoptosis. K1 has also been shown to activate the PI3K/Akt/mTOR pathway in different cells Using tandem affinity purification (TAP), we identified heat shock protein 90β (Hsp90β) and endoplasmic reticulum (ER)-associated Hsp40 (Erdj3/DnaJB11), as cellular binding partners of K1. Interactions of K1 with Hsp90β and Hsp40 were confirmed by co-immunoprecipitation in both directions. Furthermore, K1 also interacted with the Hsp90α̣ isoform. We report that siRNAs directed against Hsp90 and Hsp40/Erdj3, as well as pharmacological inhibitors of Hsp90 dramatically reduced K1 expression, suggesting that K1 is a client protein of these chaperones. Additionally, both Hsp90 and Hsp40/Erdj3 were essential for K1’s anti-apoptotic function. Finally, we report that the Hsp90 inhibitors, 17-AAG and 17-DMAG, can suppress the proliferation of KSHV-positive PEL cell lines and exhibited IC50 values of 50nM and below.

STRO-001 is a site-specific, predominantly single-species, fully human, aglycosylated anti-CD74 antibody-drug conjugate incorporating a non-cleavable linker-maytansinoid warhead with a drug-antibody ratio of 2 which was produced by a novel cell-free antibody synthesis platform. We examined the potential pharmacodynamics and anti-tumor effects of STRO-001 in multiple myeloma (MM). CD74 expression was assessed in MM cell lines and primary bone marrow (BM) MM biopsies. CD74 mRNA was detectable in CD138+ enriched plasma cells from 100% (892/892) of patients with newly diagnosed MM. Immunohistochemistry confirmed CD74 expression in 35/36 BM biopsies from patients with newly diagnosed and relapsed/refractory MM. Cytotoxicity assays demonstrated nanomolar STRO-001 potency in 4/6 MM cell lines. In ARP-1 and MM.1S tumor-bearing mice, repeat STRO-001 dosing provided significant antitumor activity with eradication of malignant hCD138+ BM plasma cells and prolonged survival. In a luciferase-expressing MM.1S xenograft model, dose-dependent STRO-001 efficacy was confirmed using bioluminescent imaging and BM tumor burden quantification. Consistent with the intended pharmacodynamic effect, STRO-001 induced dose-responsive, reversible B-cell and monocyte depletion in cynomolgus monkeys, up to a maximum tolerated 10 mg/kg, with no evidence of off-target toxicity. Collectively, these data suggest that STRO-001 is a promising therapeutic agent for the treatment of MM.

Unlike SSAs and HPs, a small subset of SEC and TSA cases demonstrated aneuploidy, suggesting that they can develop neoplasia via the CIN pathway. DNA content analysis of a larger number of SEC cases, with adequate follow-up, may allow for a more precise determination of aneuploidy incidence and neoplasia risk.