Chemoattractant receptors BLT1 and CXCR3 regulate anti-tumor immunity by facilitating CD8+ T cell migration to tumors.

Presence of increased numbers of CD8+ T cells in the tumors correspond to better overall survival in the patients. Variety of immuno-therapies have shown considerable efficacy in the clinic, however, a multitude of patients remain unresponsive. Most of these immunotherapies rely on effector T cell responses in the tumor. A major obstacle in the success of these immunotherapies is poor recruitment of CD8+ T cells into tumors despite intact effector responses in the periphery. Therefore understanding the mechanisms that regulate CTL infiltration into tumors becomes essential. Previous studies in our laboratory suggested an important role for BLT1 in immune surveillance against tumors by regulating CTL migration in a syngeneic cervical cancer tumor model. In this thesis, we investigated the roles of leukotriene B4 (LTB4) receptor - BLT1; and CXCR3, the receptor for CXCL9, CXCL10 and CXCL11 in anti-tumor immunity using a syngeneic B16 melanoma tumor model. BLT1-/- mice and CXCR3-/- mice on a C57BL/6 background were used to examine the function of these receptors in tumor progression. Significant acceleration in tumor growth and reduced survival was observed in both BLT1-/- and CXCR3-/- mice as compared to the WT mice. Analysis of tumor infiltrating leukocytes revealed significant reduction of CD8+ T cells in the tumors of BLT1-/- and CXCR3-/- mice as compared to WT tumors; their frequencies being similar in the periphery (spleen and TdLN). Significant reduction of Granzyme-B and IFNγ transcripts were observed in tumors of knockout mice compared to WT mice. Adoptive transfer of tumor experienced WT but not BLT1-/- or CXCR3-/- CD8+ T cells reduced tumor growth significantly in Rag2-/- mice, which correlated with reduced infiltration of knockout CD8+ T cells into tumors. Co-transfer of WT CD8+ T cells with either of the knockout CD8+ T cells in tumor bearing Rag2-/- mice showed that WT CD8+ T cells did not facilitate additional knockout CD8+ T cell infiltration to tumors. BLT1/CXCR3 double deficient mice displayed similar tumor kinetics as single knockout mice and showed lack of synergism. The requirement for BLT1 and CXCR3 in inducing checkpoint blockade mediated anti-tumor response was tested. While anti-PD-1 based vaccine significantly attenuated tumor growth in WT mice, the vaccine completely lost its efficacy in BLT1-/-, CXCR3-/- or BLT1-/-CXCR3-/- mice that correlated with failure of knockout CD8+ T cell infiltration into tumors. These results demonstrate a critical role for BLT1 and CXCR3 in CTL migration to tumors and thus can be targeted to enhance effective anti-tumor responses

Essential Role of Lyn in Fibrosis.

Fibrotic disorders involve replacement of normal parenchyma with myofibroblasts, which deposit connective tissue, leading to obliteration of the function of the underlying organ. The treatment options are inadequate and reflect the fact that signaling targets in myofibroblasts are unknown. Here we identify the hyperactive Lyn signaling in myofibroblasts of patients with chronic pancreatitis-induced fibrosis. Lyn activation coexpress with markers of activated myofibroblasts, and is increased ~11-fold in chronic pancreatitis compared to normal tissue. Inhibition of Lyn with siRNA or INNO-406 leads to the substantial decrease of migration and proliferation of human chronic pancreatitis myofibroblasts in vitro, while leaving migration and proliferation of normal myofibroblasts only slightly affected. Furthermore, inhibition of Lyn prevents synthesis of procollagen and collagen in myofibroblasts in a mouse model of chronic pancreatitis-induced fibrosis. We conclude that Lyn, as a positive regulator of myofibroblast migration, proliferation, and collagen production, is a key target for preventing fibrosis

Using mass spectrometry imaging to map fluxes quantitatively in the tumor ecosystem

Tumors are comprised of a multitude of cell types spanning different microenvironments. Mass spectrometry imaging (MSI) has the potential to identify metabolic patterns within the tumor ecosystem and surrounding tissues, but conventional workflows have not yet fully integrated the breadth of experimental techniques in metabolomics. Here, we combine MSI, stable isotope labeling, and a spatial variant of Isotopologue Spectral Analysis to map distributions of metabolite abundances, nutrient contributions, and metabolic turnover fluxes across the brains of mice harboring GL261 glioma, a widely used model for glioblastoma. When integrated with MSI, the combination of ion mobility, desorption electrospray ionization, and matrix assisted laser desorption ionization reveals alterations in multiple anabolic pathways. De novo fatty acid synthesis flux is increased by approximately 3-fold in glioma relative to surrounding healthy tissue. Fatty acid elongation flux is elevated even higher at 8-fold relative to surrounding healthy tissue and highlights the importance of elongase activity in glioma

A phase II study of laser interstitial thermal therapy combined with doxorubicin in patients with recurrent glioblastoma

BACKGROUND: The blood-brain barrier (BBB) is a major limiting factor for drug delivery in brain tumors. Laser interstitial thermal therapy (LITT) disrupts the peritumoral BBB. In this study, we examine survival in patients with recurrent glioblastoma (GBM) treated with LITT followed by low-dose doxorubicin, a potent anti-neoplastic drug with poor BBB permeability. METHODS: Forty-one patients with recurrent GBM were enrolled; thirty patients were evaluable. Participants underwent LITT followed by 6 weekly doxorubicin treatments starting within one week (Early Arm) or at 6-8 weeks (Late Arm) after LITT. The overall survival (OS), local progression-free survival (PFS), and any PFS were compared to historical controls treated with bevacizumab salvage therapy ( RESULTS: The Late Arm and all patients (Early Arm + Late Arm) demonstrated significant improvement in OS compared to historical controls treated with bevacizumab ( CONCLUSIONS: Low-dose doxorubicin given after LITT is well tolerated and correlated with higher OS compared to historical controls treated with bevacizumab or LITT with standard salvage chemotherapy. A larger study is needed to further characterize survival and progression patterns

A Model for Interprofessional Health Disparities Education: Student-Led Curriculum on Chronic Hepatitis B Infection

Although health disparities are commonly addressed in preclinical didactic curricula, direct patient care activities with affected communities are more limited. To address this problem, health professional students designed a preclinical service-learning curriculum on hepatitis B viral (HBV) infection, a major health disparity affecting the Asian/Pacific Islander (API) population, integrating lectures, skills training, and direct patient care at student-run clinics. An urban health professions campus. Medical and other health professional students at University of California, San Francisco, organized a preclinical didactic and experiential elective, and established two monthly clinics offering HBV screening, vaccination, and education to the community. Between 2004 and 2009, 477 students enrolled in the student-led HBV curriculum. Since the clinics’ inception in 2007, 804 patients have been screened for chronic HBV; 87% were API immigrants, 63% had limited English proficiency, and 46% were uninsured. Serologically, 10% were found to be chronic HBV carriers, 44% were susceptible to HBV, and 46% were immune. Our student-led didactic and experiential elective can serve as an interprofessional curricular model for learning about specific health disparities while providing important services to the local community

Putative role of the adenosine A3 receptor in the antiproliferative action of N6-(2-isopentenyl)adenosine

We tested a panel of naturally occurring nucleosides for their affinity towards adenosine receptors. Both N6-(2-isopentenyl)adenosine (IPA) and racemic zeatin riboside were shown to be selective human adenosine A3 receptor (hA3R) ligands with affinities in the high nanomolar range (Ki values of 159 and 649 nM, respectively). These values were comparable to the observed Ki value of adenosine on hA3R, which was 847 nM in the same radioligand binding assay. IPA also bound with micromolar affinity to the rat A3R. In a functional assay in Chinese hamster ovary cells transfected with hA3R, IPA and zeatin riboside inhibited forskolin-induced cAMP formation at micromolar potencies. The effect of IPA could be blocked by the A3R antagonist VUF5574. Both IPA and reference A3R agonist 2-chloro-N6-(3-iodobenzyl)adenosine-5′-N-methylcarboxamide (Cl-IB-MECA) have known antitumor effects. We demonstrated strong and highly similar antiproliferative effects of IPA and Cl-IB-MECA on human and rat tumor cell lines LNCaP and N1S1. Importantly, the antiproliferative effect of low concentrations of IPA on LNCaP cells could be fully blocked by the selective A3R antagonist MRS1523. At higher concentrations, IPA appeared to inhibit cell growth by an A3R-independent mechanism, as was previously reported for other A3R agonists. We used HPLC to investigate the presence of endogenous IPA in rat muscle tissue, but we could not detect the compound. In conclusion, the antiproliferative effects of the naturally occurring nucleoside IPA are at least in part mediated by the A3R