Citations

Abstract Background: Central nervous system (CNS) lymphoma, both primary and secondary disease, carries the worst prognosis of all Non-Hodgkin’s lymphoma with a 5 year survival of less than 30% with current therapeutic options. Recent studies have shown constitutive activation of both NF-κB and MAPK signaling pathways in the maintenance and progression of CNS lymphoma. This often coincides with mutations in MYD88. IRAK4 is a serine/threonine kinase that mediates interleukin 1 receptor (IL-1R) and Toll-like receptor (TLR) signaling downstream of MYD88, and is a novel therapeutic target for this disease. CA-4948 is an oral first-in-class small molecule inhibitor of IRAK4 that has demonstrated clinical activity in patients with systemic Non-Hodgkin’s Lymphoma. Our study goal was to evaluate CA-4948 efficacy in a syngeneic preclinical model of primary CNS B cell lymphoma (A20), supporting future clinical investigation of this agent in this difficult to treat disease. Materials and Methods: Plasma, cerebrospinal fluid (CSF), and brain tissue (both naïve and tumor bearing) were assessed for CA-4948 drug concentration following single high-dose oral administration using UPLC-MS/MS. Biomarker expression, including NF-κB and MAPK, was measured in control and CA-4948 treated brain tissue resected from tumor-bearing animals using multi-parameter immunohistochemistry and 3D modeling of cleared tissue. Dose-dependent survival responses were also measured using the A20 preclinical model of primary CNS lymphoma. Results: While brain concentrations of CA-4948 remained low with respect to plasma (~4-5%), therapeutic dose levels were attained in both CSF and brain tissue (>502 nM). No significant difference between naïve and A20 tumor bearing brain tissue was observed, indicating the blood brain barrier remained intact in this model. Biomarker analyses revealed significant downregulation of both MAPK and NF-κB signaling pathways in response to CA-4948, as evidenced by reduced protein levels of phospho-p38Thr180/Tyr182, phospho-ERK1/2Thr202/Tyr204, and phospho-p65Ser536 in both the tumor cells and the tumor microenvironment. Finally, CA-4948 treatment produced a dose-dependent survival response in syngeneic animals harboring CNS A20 tumors. Conclusions: CA-4948 is able to reach therapeutic dose levels in the CNS in a preclinical murine model of CNS lymphoma, producing significant and dose-dependent anti-tumor activity and survival advantage. These data support further evaluation of CA-4948 in clinical investigation and treatment of patients with CNS lymphoma. Citation Format: Christina A. von Roemeling, Bently P. Doonan, Lan Hoang-Minh, Han W. Tun, Elizabeth Martinez, Raul Soikes, Reinhard von Roemeling, Duane A. Mitchell. The IRAK4 inhibitor CA-4948 demonstrates antitumor activity in a preclinical model of CNS lymphoma [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P243.

The importance of normal circadian rhythms is underscored by the known relationship between circadian disruption and increased cancer risk. The goal of the present study was to investigate the role of the circadian clock in the regulation of genes encoding products that function in cellular transformation. Microarray analysis was used to evaluate changes in gene expression following siRNA‐mediated knockdown of the circadian clock protein Per 1 in a murine renal collecting duct cell line (mpkCCD c14 ). Several hundred genes underwent significant changes in expression following Per1 knockdown, including 21 genes involved in cellular transformation. Cdkn1a and Cyclin E1, both cell cycle regulators, claudin 1 and 12, involved in tight junction formation, and sFRP1, a regulator of Wnt signaling and a tumor suppressor in renal cell carcinoma, were all confirmed as novel Per1 target genes. In an independent sample set, Cdkn1a, Cyclin E1, Claudin 1 and 12, and sFRP1 were all up‐regulated following Per1 knockdown in mpkCCD c14 cells. The chromophobe subtype of renal cell carcinoma is thought to arise from the collecting duct. Interestingly, dysregulation of the circadian clock genes Per2 and Cry2 was observed in patient chromophobe tumor samples compared to normal tissues. These observations support a role for the circadian clock in the control of cellular transformation in the kidney.

Abstract During development of pancreatic cancer, alternatively activated macrophages contribute to fibrogenesis, pancreatic intraepithelial neoplasia (PanIN) lesion growth, and generation of an immunosuppressive environment. Here, we show that the immunomodulatory agent pomalidomide depletes pancreatic lesion areas of alternatively activated macrophage populations. Pomalidomide treatment resulted in downregulation of interferon regulatory factor 4, a transcription factor for M2 macrophage polarization. Pomalidomide-induced absence of alternatively activated macrophages led to a decrease in fibrosis at PanIN lesions and in syngeneic tumors; this was due to generation of an inflammatory, immune-responsive environment with increased expression of IL1α and presence of activated (IFNγ-positive) CD4+ and CD8+ T-cell populations. Our results indicate that pomalidomide could be used to decrease fibrogenesis in pancreatic cancer and may be ideal as a combination treatment with chemotherapeutic drugs or other immunotherapies. Significance: These findings reveal new insights into how macrophage populations within the pancreatic cancer microenvironment can be modulated, providing the means to turn the microenvironment from immunosuppressive to immune-responsive.

AbstractA major challenge in the development of cancer nanomedicine is the inability for nanomaterials to efficiently penetrate and deliver therapeutic agents into solid tumors. Previous studies have shown that tumor vasculature and extracellular matrix regulate the transvascular and interstitial transport of nanoparticles, both critical for successfully delivering nanomedicine into solid tumors. Within the malignant tumor microenvironment, blood vessels are morphologically abnormal and functionally exhibit substantial permeability. Furthermore, the tumor extracellular matrix (ECM), unlike that of the normal tissue parenchyma, is densely packed with collagen. These pathophysiological properties greatly impede intratumoral delivery of nanomaterials. By using an antivascular endothelial growth factor receptor antibody, DC101, and an antitransforming growth factor β1 (TGF‐β1) antibody, normalization of the tumor vasculature and ECM is achieved, respectively, in a syngeneic murine glioma model. This normalization effect results in a more organized vascular network, improves tissue perfusion, and reduces collagen density, all of which contribute to enhanced nanoparticle delivery and distribution within tumors. These findings suggest that combined vascular and ECM normalization strategies can be used to remodel the tumor microenvironment and improve nanomedicine delivery into solid tumors, which has significant implications for developing more effective combinational therapeutic strategies using cancer nanomedicine.

Abstract Glioblastoma is the most common primary tumor of the CNS in adults, representing approximately 50% of all gliomas and 15% of primary brain tumors. The current standard of care for GBM is safe maximal surgical resection followed by radiotherapy and concurrent Temozolomide (TMZ), but median survival continues to be 15–16 months. Temozolomide is a second-generation DNA alkylating agent that induces thymine mispairing during DNA replication resulting in tumor cell G2/M phase arrest and autophagy, a standard care of therapy against GBM. While the success of TMZ in clinical trials showed great promise for its overall efficacy, emerging TMZ resistance make us to think more for the combination therapy. CD47, a tumor cell surface marker, plays as “don't eat me signal” through binding its receptor SIRPα on macrophages and the antibody against CD47, which blocks interactions of CD47 with SIRPα, has been shown to lead to tumor destruction. Furthermore, CD47 is a prognostic marker as its expression predisposes cancer patients to a poorer survival outcome. This has significant clinical implications since approximately more than 80% of patients with the most GBMs, overexpress CD47. Overexpression of CD47 is also associated with a decreased probability of survival in clinical cohorts of GBM. Our work and that of others demonstrate that CD47 blockade enables tumor cell phagocytosis by antigen presenting cells (APC), establishing this molecule as a viable therapeutic target in GBM. We additionally investigated the combinatorial effect of CD47 blockade with temozolomide. DNA alkylating agents induce sporadic tumor cell necrosis associated with the extracellular release of damage associated molecular patterns (DAMPs) such as calreticulin, a pro-phagocytic protein whose interaction with low density lipoprotein receptor-related protein 1 (LRP1) facilitates recognition by professional antigen-presenting cells (APCs) and acts as a critical molecular component in promoting immunogenic cell. Our results showed that tumor cell treatment with temozolomide induces plasma membrane expression of calreticulin. Combination therapy resulted in amplified tumor cell phagocytosis and antigen presentation by APC. In addition, preclinical assessment of combination therapy in a syngeneic murine model of GBM resulted in significantly improved survival, characterized by increased intra-tumor penetration of APC cells. These results suggest that the combination of CD47 blockade with temozolomide may enhance tumor immunogenicity, and can improve clinical outcomes demonstrated by mono-therapeutic approaches with conventional chemotherapy. Citation Format: Yaqing Qie, Christina Von Roemeling, Yuanxin Chen, Kevin Shih, Xiujie Liu, Wen Jiang, Joshua Knight, Charles Chan, Irving Weissman, Betty Kim. CD47 blockade with temozolomide can enhance the therapy in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-208. doi:10.1158/1538-7445.AM2017-LB-208

Abstract Metabolic reprogramming plays a critical role in carcinogenesis, in part due its ability to promote immune suppressive properties within tumors. Agents that specifically target crucial metabolic enzymes utilized by cancer are been actively investigated. However, it is unclear whether inhibition of fatty acid metabolism in tumors affects their immunogenicity. Here, we show for the first time that inhibition of stearoyl-CoA desaturase 1 (SCD1), a key enzyme involved in fatty-acid synthesis and a potential prognostic marker for human cancers, increases the immunogenicity of poorly immunogenic tumors. The enhanced immune activation is accompanied by upregulated endoplasmic reticulum (ER) stress and is dependent on the translocation of ER protein calreticulin to the tumor cell surface. Inhibition of SCD1 increased both recruitment and activation of immune cells in vivo, which when combined with PD-1 blockade resulted in potent and durable anti-tumor T cell responses. Together, our results indicate that inhibition of tumorigenic de novo lipogenesis represents a novel approach to enhance T cell based cancer immunotherapy. Citation Format: Christina Anna Elizabeth Von Roemeling, Thomas Caulfield, Yaqing Qie, Derek C. Radisky, Xiujie Liu, Yuanxin Chen, Joshua Knight, John Copland, Betty Kim. Blockade of stearoyl CoA desaturase 1 promotes immunogenic clearance of tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-189. doi:10.1158/1538-7445.AM2017-LB-189