CROI 2020 Abstract eBook

Abstract eBook

Oral Abstracts

Chemical inhibition of xCT induces ferroptotic death only in KSHV-infected LEC, suggesting that enhanced xCT function is central to the ability of infected cells to resist ferroptosis. KSHV also upregulates the oxidoreductase FSP1 (formerly AIFM2), the key component of the novel CoQ-dependent FSP, identifying a second ferroptosis escape mechanism in infected cells. Conclusion: We have identified unique vulnerabilities in KSHV-infected cells that reflect the delicate pro/antioxidant balance required to facilitate growth and survival. Our work suggests that selective induction of ferroptosis in KSHV- infected cells represents a promising anti-KS strategy. 66 GENE EXPRESSION PATTERNS IN SKIN VS GASTROINTESTINAL KAPOSI SARCOMA LESIONS Ramya Ramaswami 1 , Takanobu Tagawa 1 , Vishal Koparde 2 , Kathryn Lurain 1 , Anna Serquina 1 , Anaida Widell 1 , Irene Ekwede 1 , Robert Yarchoan 1 , Joseph Ziegelbauer 1 1 National Cancer Institute, Bethesda, MD, USA, 2 National Cancer Institute, Frederick, MD, USA Background: Kaposi sarcoma (KS), caused by Kaposi sarcoma herpesvirus (KSHV), is a multicentric tumor characterized by abnormal vasculature and proliferation of KSHV-infected spindle cells. KS involves the skin (sk) but can also affect the gastrointestinal tract (gi) in severe cases. Little is known about host and viral gene expression differences in patients with KS lesions. Here, we performed RNA sequencing of sk and gi KS lesions from HIV+ patients with KS to understand the similarities and differences in the gene expression pattern. Methods: We obtained fresh sk and gi KS lesions with matched normal sk and gi samples. Total RNA was extracted from samples and RNA expression was analyzed using paired-end RNA-Seq. Differential gene expression was measured by comparing KS lesions to normal matched samples. We used programs STAR and DESeq2 to identify differentially expressed genes with a False Discovery Rate cut-off of 0.05. Results: Six samples were obtained (sk (4) and gi (2)) from 5 HIV+ patients with KS. All tumors were stage T1. Only 2 pts had received prior KS therapy. In sk KS, cellular gene networks associated with cell adhesion (extracellular matrix), immune response, angiogenesis, and proteolysis were dysregulated when compared with normal skin. There were 13 cellular genes increased in both sk and gi KS lesions (Figure 1). Of these genes those that were clinically significant included FLT4 , which encodes for a receptor of VEGF-C and VEGF-D, and RIOX1, a histone demethylase and potential independent prognostic factor for venous invasion and lymphatic duct invasion in colon cancer. The most expressed viral genes were a mixture of latent and lytic genes in sk KS samples. There were more lytic viral genes detected in gi KS as compared to sk KS, which may be due to more advanced KS or a difference in lytic activation in gi tissues. One patient had both sk and gi KS (with matched normal samples), which demonstrated 19 genes that were strongly increased in both tissues and included cellular genes ADAMTS4, RIOX1, ACAN. Conclusion: This is one of the first studies comparing sk and gi KS that highlights differences in viral gene and clinically relevant host gene expression between these tissues. By analyzing these gene expression patterns, this ongoing study will improve our understanding of KS pathogenesis.

valganciclovir started before cART could diminish HHV-8-VL and reduce the incidence of S-KS-IRIS and its atributable mortality. Methods: ORCT (Clincal Trials NIH ID NCT03296553) of patients with disseminated KS (DKS), approved by IRB, participants signed informed consent. Inclusion criteria: AIDS cART naïve patients with at least two of the following: pulmonary disease, 30 skin lesions, lymphedema, lymph node involvement, GIT involvement. Exclusion criteria: other malignant disease, steroid treatment, active Hepatitis B or C, CMV end-organ disease; and APACHE >15. S-IRIS-KS definition: abrupt clinical exacerbation of KS after starting cART and at least 3 of the following parameters: thrombocytopenia, anemia, hyponatremia, hypoalbuminemia or fever. Experimental group (EG) started valganciclovir 900 mg BID 4 weeks before cART and continued until week 48; control group (CG) started cART at week 0. Treating physician determined Vincristine/Bleomycin administration. Scheduled visits: weeks 0,1,2,4,8,12,16,24, and 48. In each visit HIV-VL, HHV-8 VL (ELITe M GB KIT) CD4 and CD8 count by flow cytometry. Results: 38 patients were randomized, 19 in each group; one patient stopped valganciclovir and was excluded. Three patients died due to S-IRIS-KS in the CG, two died in the EG (opiod overdose and H1NI pneumonia). Four patients developed 12 episodes of S-IRIS-KS in the CG (IR of 0.21 per/100 patient-days), two patients, one episode each in the EG (IR 0.038 per/100 patient-days) p=0.007. In multivariate poisson or negative binomial models, higher-baseline CD4 decreased and higher HHV8-VL increased consistently the risk of S-IRIS-KS; Valganciclovir treatment reduced S-SIRI-KS events (IRR= 0.06, 95%CI 0.004-0.7 p=0.024) and the number of patients with at least one S-IRIS-KS episode (, IRR 0.24, 95%CI 0.03, 2.27, p= 0.21). Conclusion: Valganciclovir reduced episodes of S-IRIS-KS and its attributable mortality. Measurement of HHV-8 VL may be important in the clinical care of DKS. Vickie Marshall 1 , Catherine Brands 1 , Nazzarena Labo 1 , Vicky Coalter 1 , Jeffrey D. Lifson 1 , Denise Whitby 1 , Claire Deleage 1 , Gregory Q. Del Prete 1 1 AIDS and Cancer Virus Program, Frederick, MD, USA Background: Gammaherpesviruses are a clinically significant cause of cancer and are primarily transmitted via saliva. However, the specific sites of viral replication in oral tissues resulting in salivary shedding are poorly understood. Rhesus macaques (RM) are naturally infected with three gammaherpesviruses: retroperitoneal fibromatosis herpesvirus (RFHV), an ortholog of KSHV, rhesus lymphocryptovirus (RLCV), closely related to EBV, and rhesus rhadinovirus (RRV). Rhesus macaques have been used as models of gammaherpesvirus-associated malignancies in the context of SHIV/SIV infection and offer an opportunity to study oral biology of gammaherpesviruses in greater detail. Methods: Oral fluid and oral tissues from 30 RM experimentally infected with SIV or not were collected during necropsy. These included buccal and gingival tissue, parotid, submandibular and sublingual salivary glands, submandibular lymph nodes, adenoid, palatine and inguinal tonsil, soft palate and tongue. DNA was extracted and tested by qPCR for RRV, RLCV, and RFHV viral load. In situ hybridization targeting viral DNA was performed, for all 3 viruses, in all tissue types and highly positive tissues were used to phenotype the cells harboring viral DNA. Results: Rhesus gammaherpesviruses were detected in the oral fluid and oral tissues of all 30 animals examined; many were positive for more than one virus. By qPCR, the highest levels of RFHV were identified in gingiva, tongue, and submandibular lymph nodes while the highest levels of RLCV and RRV were detected in adenoid and palatine tonsil. Using ISH, most infection events for all three viruses were visualized in lymphoid tissues including lymph node and palatine tonsil. Multiplexing ISH with antibody-based phenotyping revealed a broad range of infected cell types including B- and T-lymphocytes, fibroblasts, epithelial cells, and NK-cells. Certain infected cell types, especially for RFHV, remain unidentified and phenotyping experiments are ongoing. Conclusion: This is the first study examining RRV, RLCV, and RFHV viral load in rhesus oral tissues and oral fluid and may provide insights into human gammaherpesvirus biology within the oral compartment.

Oral Abstracts

68 SURVEILLANCE OF RHESUS MACAQUE TISSUES IDENTIFYING GAMMAHERPESVIRUS INFECTION SITES

67LB IMPACT OF VALGANCICLOVIR THERAPY ON SEVERE IRIS–KAPOSI SARCOMA–ATTRIBUTABLE MORTALITY Patricia Volkow 1 , Beda Daniela Islas Muñoz 1 , Leslie Chávez-Galán 2 , Lucero Ramón-Luing 2 , Dora Patricia Cornejo Juárez 1 , Judith Cruz-Velázquez 1 , for the Kaposi Sarcoma 1 Instituto Nacional de Cancerología, Mexico City, Mexico, 2 National Autonomous University of Mexico, Mexico City, Mexico Background: High HHV-8 viral load (VL) has been associated with severe Kaposi sarcoma (S-KS). KS Immune reconstitution inflammatory syndrome (IRIS) can occur in patients after starting cART with associated high mortality. Ganciclovir has anti-HHV8 activity. Our objective was to investigate if

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CROI 2020