HIV-1 Associated Neurocognitive Disorder (HAND) is a common and clinically detrimental complication of HIV infection. Viral proteins, including Tat, released from infected cells, cause neuronal toxicity. Substance abuse in HIV-infected patients greatly influences the severity of neuronal damage. To repurpose small molecule inhibitors for anti-HAND therapy, we employed MOLIERE, an AI-based literature mining system that we developed. All human genes were analyzed and prioritized by MOLIERE to find previously unknown targets connected to HAND. From the identified high priority genes, we narrowed the list to those with known small molecule ligands developed for other applications and lacking systemic toxicity in animal models. To validate the AI-based process, the selective small molecule inhibitor of DDX3 helicase activity, RK-33, was chosen and tested for neuroprotective activity. The compound, previously developed for cancer treatment, was tested for the prevention of combined neurotoxicity of HIV Tat and cocaine. Rodent cortical cultures were treated with 6 or 60 ng/ml of HIV Tat and 10 or 25 μM of cocaine, which caused substantial toxicity. RK-33 at doses as low as 1 μM greatly reduced the neurotoxicity of Tat and cocaine. Transcriptome analysis showed that most Tat-activated transcripts are microglia-specific genes and that RK-33 blocks their activation. Treatment with RK-33 inhibits the Tat and cocaine-dependent increase in the number and size of microglia and the proinflammatory cytokines IL-6, TNF-α, MCP-1/CCL2, MIP-2, IL-1α and IL-1β. These findings reveal that inhibition of DDX3 may have the potential to treat not only HAND but other neurodegenerative diseases. RK-33, selective inhibitor of Dead Box RNA helicase 3 (DDX3) protects neurons from combined Tat and cocaine neurotoxicity by inhibition of microglia activation and production of proinflammatory cytokines.

Malignant peripheral nerve sheath tumor (MPNST) is a rare but aggressive soft-tissue sarcoma characterized by poor response to therapy. The primary treatment remains surgical resection with negative margins. Nonetheless, in the setting of neurofibromatosis type 1 (NF1), the five-year survival rate is at 20–50%, with recurrence occurring in up to 50% of individuals. For patients with metastatic and unresectable disease, current treatment options include cytotoxic chemotherapy, which offers minimal benefit, and most patients die within five years of diagnosis. Despite advances in targeted therapy focusing on inhibiting Ras signaling and its downstream effectors, clinical trials report minimal clinical benefit, highlighting the need to explore alternative pathways in MPNST pathogenesis. Here, we discuss the role of the E3 ubiquitin ligase, UBR5, in cancer progression and immune modulation across various malignancies, including breast, lung, and ovarian cancer. We focus on mechanisms by which UBR5 contributes to tumorigenesis, focusing on its influence on tumor microenvironment and immune modulation. Additionally, we explore UBR5’s roles in normal tissue function, DNA damage response, metastasis, and therapeutic resistance, illustrating its multifaceted contribution to cancer biology. We discuss evidence implicating UBR5 in immune evasion and highlight its potential as a therapeutic target to enhance the efficacy of immune checkpoint blockade (ICB) therapy in MPNST, a tumor typically characterized by an immune cold microenvironment. We outline current immune-based strategies and challenges in MPNST management, ongoing efforts to shift the immune landscape in MPNST, and ultimately, we suggest that targeting UBR5 could be a novel strategy to potentiate ICB therapy-mediated anti-tumor immune response and clinical outcomes, particularly in MPNST patients with inoperable or metastatic disease.

HIV-associated neurological disorder (HAND) is a serious complication of HIV infection, marked by neurotoxicity induced by viral proteins like Tat. Substance abuse exacerbates neurocognitive impairment in people living with HIV. There is an urgent need for effective therapeutic strategies to combat HAND comorbid with Cocaine Use Disorder (CUD). Our analysis of the HIV and cocaine-induced transcriptomes in primary cortical cultures revealed a significant overexpression of the macrophage-specific gene, aconitate decarboxylase 1 (Acod1), caused by the combined insults of HIV and cocaine. ACOD1 protein converts the tricarboxylic acid intermediate cis-aconitate into itaconate during the activation of inflammation. The itaconate produced facilitates cytokine production and subsequently activates anti-inflammatory transcription factors, shielding macrophages from infection-induced cell death. While the role of itaconate’ in limiting inflammation has been studied in peripheral macrophages, its immunometabolic function remains unexplored in HIV and cocaine-exposed microglia. We assessed in this model system the potential of 4-octyl-itaconate (4OI), a cell-penetrable esterified form of itaconate known for its potent anti-inflammatory properties and potential therapeutic applications. We administered 4OI to primary cortical cultures exposed to Tat and cocaine. 4OI treatment increased the number of microglial cells in both untreated and Tat±Cocaine-treated cultures and also reversed the morphological altercations induced by Tat and cocaine. In the presence of 4OI, microglial cells also appeared more ramified, resembling the quiescent microglia. Consistent with these results, 4OI treatment inhibited the secretion of the proinflammatory cytokines IL-1α, IL-1β, IL-6, and MIP1-α induced by Tat and cocaine. Transcriptome profiling further determined that Nrf2 target genes such as NAD(P)H quinone oxidoreductase 1 (Nqo1), Glutathione S-transferase Pi (Gstp1), and glutamate cysteine ligase catalytic (Gclc), were most significantly activated in Tat-4OI treated cultures, relative to Tat alone. Further, genes associated with cytoskeleton dynamics in inflammatory microglia were downregulated by 4OI treatment. Together, the results strongly suggest 4-octyl-itaconate holds promise as a potential candidate for therapeutic development aimed at addressing HAND coupled with CUD comorbidities. Abstract Figure: Graphical Model of 4OI-mediated neuroprotection against Tat-Cocaine toxicity: Tat and Tat-Cocaine treatment induce neuronal damage, which is mitigated by 4OI through microglia cells. This cartoon shows the reduction of harmful effects such as proinflammatory cytokine release, upregulation of P2R, PDE, and Acod1 by the presence of 4OI. This ester modified itaconate triggers anti-inflammatory responses and activates antioxidant pathways.

Despite aggressive multimodal treatment with chemoradiation or surgery and adjuvant radiation therapy (RT) +/- chemotherapy, recurrence rates approach 50% for locally advanced human papillomavirus (HPV)-negative HNSCC. Thus, more effective therapeutics are needed in both the upfront and recurrent settings to improve outcomes for HNSCC patients. Ataxia telangiectasia and Rad 3-related (ATR) is a potential therapeutic target that may enhance RT response. ATR is a DNA damage response protein activated by replication stress and single-strand DNA breaks, such as those caused by RT. We hypothesize that ATR inhibition radiosensitizes tumors by preventing DNA repair and forcing HNSCC cells with unrepaired DNA damage into mitosis, leading to cell death. We evaluated the effects of ATR inhibitor BAY 1895344 (BAY) in preclinical models of HPV-negative HNSCC using murine and human cell lines, including MOC1, MOC2, JHU-012, and FaDu. We confirmed dose-dependent inhibition of ATR signaling by BAY using Western blot analysis of downstream phosphorylated CHK1 in cells treated with RT+vehicle versus RT+BAY. Additionally, dose-dependent increase in yH2AX (DNA damage marker) was observed at 18 hours post-RT in cells treated with serial dilutions of BAY vs vehicle. In clonogenic assays, cells treated with 100nM BAY (4h) and 0-8Gy RT demonstrated radiosensitization compared to vehicle. Cell cycle analysis showed that BAY pre-treatment significantly abrogated RT-induced G2/M cell cycle arrest (p<0.01, unpaired t-test). Cells treated with BAY before RT vs vehicle + RT or BAY alone exhibited increased co-staining for yH2AX and pHH3 (mitosis marker) by flow cytometry and immunofluorescence, indicative of mitotic catastrophe. Additionally, MOC2 cells treated with BAY alone or BAY + RT exhibited significantly increased micronuclei and multinucleation events at 24 hours compared to vehicle alone (p=0.0009, unpaired t test) or vehicle + RT (p=0.01), respectively. For in vivo evaluation of BAY in a radioresistant syngeneic mouse model, intramuscular MOC2 tumors were induced in the gastrocnemius of C57BL/6J mice. When tumors reached 70-280 mm³, mice were randomized (n=10/group) to receive vehicle, BAY (40mg/kg), RT (8Gy x 3), or BAY + RT. Image-guided RT was administered every 4 days. Vehicle or BAY was given orally twice on the day of RT or sham RT (morning/evening) and once the morning after RT or sham RT. Median survival was significantly increased in treated groups: 39.5d for BAY + RT vs. 14d for vehicle + sham RT (p=0.0002, Log-rank test), 22d for BAY + sham RT (p=0.0003), and 23d for vehicle + RT (p=0.0007). Thus, the small molecule ATR inhibitor BAY 1895344 radiosensitizes HNSCC in vitro and increases survival combined with RT in vivo, indicating therapeutic potential for targeting ATR in head and neck cancer. The combination of BAY 1895344 (elimusertib), pembrolizumab, and stereotactic body radiation therapy is currently being tested in a phase I clinical trial for patients with unresectable or metastatic HNSCC within a previously irradiated field (NCT04576091). Citation Format: Allison N. Pittman, Diana A. Odhiambo, Rico J. Castillo, Ashlyn G. Rickard, Joshua Chen, Joshua E. Himes, Alex M. Bassil, Nerissa T. Williams, David G. Kirsch, Yvonne M. Mowery. Evaluating the therapeutic potential of ATR inhibitor BAY 1895344 and radiation therapy for head and neck squamous cell carcinoma [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Innovating through Basic, Clinical, and Translational Research; 2023 Jul 7-8; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2023;29(18_Suppl):Abstract nr IA04.

Malignant peripheral nerve sheath tumor (MPNST) is a rare but aggressive soft-tissue sarcoma characterized by poor response to therapy. The primary treatment remains surgical resection with negative margins. Nonetheless, in the setting of neurofibromatosis type 1 (NF1), the five-year survival rate is at 20-50% with recurrence occurring in up to 50% of individuals. For patients with metastatic and unresectable disease, current treatment options include cytotoxic chemotherapy, which offers minimal benefit, and most patients die within five years of diagnosis. Despite advances in targeted therapy focusing on inhibiting Ras signaling and its downstream effectors, clinical trials report minimal clinical benefit, highlighting the need to explore alternative pathways in MPNST pathogenesis. Here we discuss the role of the E3 ubiquitin ligase, UBR5, in cancer progression and immune modulation across various malignancies including breast, lung and ovarian cancer. We focus on mechanisms by which UBR5 contributes to tumorigenesis focusing on its influence on tumor microenvironment and immune modulation. We discuss evidence implicating UBR5 in immune evasion and highlight its potential as a therapeutic target to enhance the efficacy of immune checkpoint blockade (ICB) therapy in MPNST, a tumor typically characterized by an immune cold microenvironment. We outline current immune-based strategies and challenges in MPNST management, ongoing efforts to shift the immune landscape in MPNST, and ultimately, we suggest that targeting UBR5 could be a novel strategy to potentiate ICB therapy-mediated anti-tumor immune response and clinical outcomes, particularly in MPNST patients with inoperable or metastatic disease.