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T cell activation stimulates substantially increased protein synthesis activity to accumulate sufficient biomass for cell proliferation. The protein synthesis is fueled by the amino acids transported from the environment. Steroid nuclear receptor coactivator 2 (SRC2) is a member of a family of transcription coactivators. Here, we show that SRC2 recruited by c-Myc enhances CD4 + T cell activation to stimulate immune responses via upregulation of amino acid transporter Slc7a5. Mice deficient of SRC2 in T cells ( SRC2 fl/fl /CD4 Cre ) are resistant to the induction of experimental autoimmune encephalomyelitis (EAE) and susceptible to Citrobacter rodentium ( C. rodentium ) infection. Adoptive transfer of naive CD4 + T cells from SRC2 fl/fl /CD4 Cre mice fails to elicit EAE and colitis in Rag1 / recipients. Further, CD4 + T cells from SRC2 fl/fl /CD4 Cre mice display defective T cell proliferation, cytokine production, and differentiation both in vitro and in vivo. Mechanically, SRC2 functions as a coactivator to work together with c-Myc to stimulate the expression of amino acid transporter Slc7a5 required for T cell activation. Slc7a5 fails to be up-regulated in CD4 + T cells from SRC2 fl/fl /CD4 Cre mice, and forced expression of Slc7a5 rescues proliferation, cytokine production, and the ability of SRC2 fl/fl /CD4 Cre CD4 + T cells to induce EAE. Therefore, SRC2 is essential for CD4 + T cell activation and, thus, a potential drug target for controlling CD4 + T cell-mediated autoimmunity.

Purpose: mAbs blocking immune checkpoints have emerged as important cancer therapeutics, as exemplified by systemic administration of the IgG1 anti-CD47 mAb that blocks the “don't eat me” pathway. However, this strategy is associated with severe toxicity. Experimental Design: To improve therapeutic efficacy while reducing toxicities for ovarian cancer, we engineered an oncolytic herpesvirus (oHSV) to express a full-length, soluble anti-CD47 mAb with a human IgG1 scaffold (OV-αCD47-G1) or IgG4 scaffold (OV-αCD47-G4). Results: Both IgG1 and IgG4 anti-CD47 mAbs secreted by oHSV-infected tumor cells blocked the CD47–SIRPα signal pathway, enhancing macrophage phagocytosis against ovarian tumor cells. OV-αCD47-G1, but not OV-αCD47-G4, activated human NK-cell cytotoxicity and macrophage phagocytosis by binding to the Fc receptors of these cells. In vivo, these multifaceted functions of OV-αCD47-G1 improved mouse survival in xenograft and immunocompetent mouse models of ovarian cancer when compared with OV-αCD47-G4 and a parental oHSV. The murine counterpart of OV-αCD47-G1, OV-αmCD47-G2b, also enhanced mouse NK-cell cytotoxicity and macrophage phagocytosis and prolonged survival of mice bearing ovarian tumors compared with OV-αmCD47-G3. OV-αmCD47-G2b was also superior to αmCD47-G2b and showed a significantly better effect when combined with an antibody against PD-L1 that was upregulated by oHSV infection. Conclusions: Our data demonstrate that an oHSV encoding a full-length human IgG1 anti-CD47 mAb, when used as a single agent or combined with another agent, is a promising approach for improving ovarian cancer treatment via enhancing innate immunity, as well as performing its known oncolytic function and modulation of immune cells.

OV-αmCD47-G2b treatments promote macrophage M1 polarization and NK cell activation in ID8 immunocompetent ovarian cancer metastasis mouse model.

Primers used in this study.

All supplementary data: supplementary figures s1-s13 and table s1

Purpose:mAbs blocking immune checkpoints have emerged as important cancer therapeutics, as exemplified by systemic administration of the IgG1 anti-CD47 mAb that blocks the “don't eat me” pathway. However, this strategy is associated with severe toxicity.Experimental Design:To improve therapeutic efficacy while reducing toxicities for ovarian cancer, we engineered an oncolytic herpesvirus (oHSV) to express a full-length, soluble anti-CD47 mAb with a human IgG1 scaffold (OV-αCD47-G1) or IgG4 scaffold (OV-αCD47-G4).Results:Both IgG1 and IgG4 anti-CD47 mAbs secreted by oHSV-infected tumor cells blocked the CD47–SIRPα signal pathway, enhancing macrophage phagocytosis against ovarian tumor cells. OV-αCD47-G1, but not OV-αCD47-G4, activated human NK-cell cytotoxicity and macrophage phagocytosis by binding to the Fc receptors of these cells. In vivo, these multifaceted functions of OV-αCD47-G1 improved mouse survival in xenograft and immunocompetent mouse models of ovarian cancer when compared with OV-αCD47-G4 and a parental oHSV. The murine counterpart of OV-αCD47-G1, OV-αmCD47-G2b, also enhanced mouse NK-cell cytotoxicity and macrophage phagocytosis and prolonged survival of mice bearing ovarian tumors compared with OV-αmCD47-G3. OV-αmCD47-G2b was also superior to αmCD47-G2b and showed a significantly better effect when combined with an antibody against PD-L1 that was upregulated by oHSV infection.Conclusions:Our data demonstrate that an oHSV encoding a full-length human IgG1 anti-CD47 mAb, when used as a single agent or combined with another agent, is a promising approach for improving ovarian cancer treatment via enhancing innate immunity, as well as performing its known oncolytic function and modulation of immune cells.

While dip direction is a fundamental parameter of slab geometry, it is rarely estimated quantitatively. Here, we develop a new method, Dip Direction Searching (DDS), of receiver functions (RFs) that reduces the uncertainty of slab dip direction estimation from tens to several degrees. DDS can also resolve the thickness and depth of a dipping structure. We then apply DDS to the RFs in the Sumatran subduction zone. Travel time differences of the converted phases from the upper and lower (oceanic Moho) boundaries of the dipping low-velocity layer (LVL) along the plate interface show a thickness of 10–14 km. The results also show increased dip direction of the slab Moho from 47 ± 5.3° in southern Sumatra to 70 ± 10.7° in northern Sumatra, indicating a complicated slab geometry and internal deformation along strike. Similar dip directions are obtained for the upper and lower LVL boundaries beneath Nias and Enggano forearc islands in the north and south, whereas we find a larger discrepancy of ∼14–23° beneath Siberut and Pagai in between. The thicker LVL with a non-negligible difference in the dip directions of its upper and lower bounds in the center of Sumatra is interpreted as a partially serpentinized mantle layer above the oceanic crust, forming a distinct channel atop the subducting slab. Our results provide basic observational constraints on the structure and geometry of the oceanic slab and associated subduction processes. Both synthetics and data analyses also indicate DDS can be applied in other subduction zones and for other dipping interfaces. Ministry of Education (MOE) National Research Foundation (NRF) Published version This research is jointly supported by the National Natural Science Foundation of China (Grant 42288201), the Strategic Priority Research Program (A) of Chinese Academy of Sciences (Grant XDA20070302) and Singapore MOE tier-2 Grant (MOE2019-T2-1-182 (S)). This research was supported by the Earth Observatory of Singapore via its funding from the National Research Foundation Singapore and the Singapore Ministry of Education under the Research Centres of Excellence initiative. This work comprises EOS contribution number 522. M. Feng thanks the Chinese Scholarship Council for scholarship fund.

Oncolytic herpes simplex virus-1 is capable of lysing tumor cells while alerting the immune system. CD47, in collaboration with SIRPα, represents an important immune checkpoint to inhibit phagocytosis by innate immune cells. Here we show locoregional control of glioblastoma by an oncolytic herpes virus expressing a full-length anti(α)-human CD47 IgG1 or IgG4 antibody. The antibodies secreted by the virus-infected glioblastoma cells block the CD47 ‘don’t eat me’ signal irrespective of the subclass; however, αCD47-IgG1 has a stronger tumor killing effect than αCD47-IgG4 due to additional antibody-dependent cellular phagocytosis by macrophages and antibody-dependent cellular cytotoxicity by NK cells. Intracranially injected αCD47-IgG1-producing virus continuously releases the respective antibody in the tumor microenvironment but not into systemic circulation; additionally, αCD47-IgG1-producing virus also improves the survival of tumor-bearing mice better than control oncolytic herpes virus combined with topical αCD47-IgG1. Results from immunocompetent mouse tumor models further confirm that macrophages, and to a lesser extent NK cells, mediate the anti-tumor cytotoxicity of antibody-producing oncolytic herpesviruses. Collectively, oncolytic herpes simplex virus-1 encoding full-length antibodies could improve immune-virotherapy for glioblastoma., Oncolytic herpes simplex virus-1 lyses cancer cells while increases their immunogenicity. Blocking the CD47 “don’t eat me” signal on cancer cells promotes their phagocytosis by macrophages. Authors here show that oncolytic viruses expressing anti-CD47 antibodies improve glioblastoma survival in mouse models.

Integrins have long been sought as therapeutic targets in cancer, but there are no FDA approved drugs to target this gene family. Since integrins require the dimerization between an alpha and beta subunit to function, we developed a CRISPR library targeting all 26 alpha and beta subunits to identify which pair is the most important. We found a strong correlation between ITGAV and ITGB5 (Integrin Beta 5), which form a known heterodimer, in solid tumors. CRISPR targeting either ITGAV or ITGB5 led to attenuated cell proliferation with increased cell cycle stalling and apoptosis. As the more essential partner, we designed a CRISPR tiling scan targeting the entire coding region of ITGAV and determine the essential nature of each amino acid. We found a sub-domain within the beta propeller to be important for ITGAV function, the CRISPR identified pocket (CIP). Genetic targeting of this pocket disrupted the ability to detect the heterodimer signal of ITGAV-ITGB5 by a specific antibody. Furthermore, we confirmed that essential amino acids within the CIP responsible for the heterodimer stability by the NanoBRET energy transfer system. Knowing the role of the CIP in heterodimer stability we searched for a small molecule to bind in the CIP to phenocopy our genetic findings. A combined in-silico and in-vitro high throughput drug screen started tested compounds for cell killing and disruption of the ITGAV-ITGB5 heterodimer. “Compound 2” (cpd_2) showed both strong cell killing and dissociation of the heterodimer. Disruption was measured by detection by flow cytometry and through the NanoBRET system. Cpd_2’s binding was confirmed with thermal shift studies with purified ITGAV beta propeller, validating that this compound is behaving and binding as we expect at the CIP. Next, we sought to understand how the ITGAV-ITGB5 heterodimer controls cancer cell survival. From the Dependency Map Public database (DepMap) we found that Rac1 dependency is significantly correlated only with ITGAV and ITGB5. We hypothesized that this meant that ITGAV-ITGB5 regulated Rac1 activity. Loss of Rac1 phenocopies knock out of ITGAV or ITGB5 and loss of either Rac1 or ITGAV led to dysregulation of the actin cytoskeleton, a known downstream feature of Rac1. A constitutively Rac1 (CA_Rac1) rescues the effects of targeting of ITGAV or treatment with cpd_2. Altogether this data suggests that ITGAV-ITGB5 signals to Rac1 and that attenuation of their function can be reversed by an active Rac1 In summary, our study highlights a novel strategy of targeting the integrin heterodimer ITGAV-ITGB5 with a small molecule binding to a novel subdomain, CIP, of ITGAV. The CIP is responsible for the heterodimer stability of ITGAV and ITGB5. Disruption of this heterodimer led to the dysregulation of Rac1 and destabilization of the actin cytoskeleton. This mechanism highlights a novel strategy for targeting integrins as a therapeutic target in cancer. Citation Format: Nicole Mattson, Kazuya Miyashita, Anthony Chan, Lu Yang, Sheela Pangeni Pokharel, Wei Liu, Ming li, Qiao Liu, Xiaobao Xu, Priyanka Singh, Leisi Zhang, Mingye Feng, Chun-Wei Chen. Targeting integrin alpha V beta 5 heterodimer stability using a novel small molecular inhibitor for tumor suppression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6234.

Steroid nuclear receptor coactivator 2 (SRC2) is a member of a family of transcription coactivators. While SRC1 inhibits the differentiation of regulatory T cells (T regs ) critical for establishing immune tolerance, we show here that SRC2 stimulates T reg differentiation. SRC2 is dispensable for the development of thymic T regs , whereas naive CD4 + T cells from mice deficient of SRC2 specific in T regs ( SRC2 fl/fl /Foxp3 YFP-Cre ) display defective T reg differentiation. Furthermore, the aged SRC2 fl/fl /Foxp3 YFP-Cre mice spontaneously develop autoimmune phenotypes including enlarged spleen and lung inflammation infiltrated with IFNγ-producing CD4 + T cells. SRC2 fl/fl /Foxp3 YFP-Cre mice also develop severer experimental autoimmune encephalomyelitis (EAE) due to reduced T regs . Mechanically, SRC2 recruited by NFAT1 binds to the promoter and activates the expression of Nr4a2 , which then stimulates Foxp3 expression to promote T reg differentiation. Members of SRC family coactivators thus play distinct roles in T reg differentiation and are potential drug targets for controlling immune tolerance.

Tumor-associated macrophages (TAMs) are one of the most abundant immune components in the tumor microenvironment and play a plethora of roles in regulating tumorigenesis. Therefore, the therapeutic targeting of TAMs has emerged as a new paradigm for immunotherapy of cancer. Herein, the review summarizes the origin, polarization, and function of TAMs in the progression of malignant diseases. The understanding of such knowledge leads to several distinct therapeutic strategies to manipulate TAMs to battle cancer, which include those to reduce TAM abundance, such as depleting TAMs or inhibiting their recruitment and differentiation, and those to harness or boost the anti-tumor activities of TAMs such as blocking phagocytosis checkpoints, inducing antibody-dependent cellular phagocytosis, and reprogramming TAM polarization. In addition, modulation of TAMs may reshape the tumor microenvironment and therefore synergize with other cancer therapeutics. Therefore, the rational combination of TAM-targeting therapeutics with conventional therapies including radiotherapy, chemotherapy, and other immunotherapies is also reviewed. Overall, targeting TAMs presents itself as a promising strategy to add to the growing repertoire of treatment approaches in the fight against cancer, and it is hopeful that these approaches currently being pioneered will serve to vastly improve patient outcomes and quality of life.

Macrophages are essential in eliciting antibody-dependent cellular phagocytosis (ADCP) of cancer cells. However, a satisfactory anticancer efficacy of ADCP is contingent on early antibody administration, and resistance develops along with cancer progression. Here, we investigate the mechanisms underlying ADCP and demonstrate an effective combinatorial strategy to potentiate its efficacy. We identified paclitaxel as a universal adjuvant that efficiently potentiated ADCP by a variety of anticancer antibodies in multiple cancers. Rather than eliciting cytotoxicity on cancer cells, paclitaxel polarized macrophages toward a state with enhanced phagocytic ability. Paclitaxel-treated macrophages down-regulated cell surface CSF1R whose expression was negatively correlated with patient survival in multiple malignancies. The suppression of CSF1R in macrophages enhanced ADCP of cancer cells, suggesting a role of CSF1R in regulating macrophage phagocytic ability. Together, these findings define a potent strategy for using conventional anticancer drugs to stimulate macrophage phagocytosis and promote the therapeutic efficacy of clinical anticancer antibodies.

Tumor-associated macrophages (TAMs) are often the most abundant immune cells in the tumor microenvironment (TME). Strategies targeting TAMs to enable tumor cell killing through cellular phagocytosis have emerged as promising cancer immunotherapy. Although several phagocytosis checkpoints have been identified, the desired efficacy has not yet been achieved by blocking such checkpoints in preclinical models or clinical trials. Here, we showed that late-stage non-Hodgkin lymphoma (NHL) was resistant to therapy targeting phagocytosis checkpoint CD47 due to the compromised capacity of TAMs to phagocytose lymphoma cells. Via a high-throughput screening of the US Food and Drug Administration–approved anticancer small molecule compounds, we identified paclitaxel as a potentiator that promoted the clearance of lymphoma by directly evoking phagocytic capability of macrophages, independently of paclitaxel’s chemotherapeutic cytotoxicity toward NHL cells. A combination with paclitaxel dramatically enhanced the anticancer efficacy of CD47-targeted therapy toward late-stage NHL. Analysis of TME by single-cell RNA sequencing identified paclitaxel-induced TAM populations with an upregulation of genes for tyrosine kinase signaling. The activation of Src family tyrosine kinases signaling in macrophages by paclitaxel promoted phagocytosis against NHL cells. In addition, we identified a role of paclitaxel in modifying the TME by preventing the accumulation of a TAM subpopulation that was only present in late-stage lymphoma resistant to CD47-targeted therapy. Our findings identify a novel and effective strategy for NHL treatment by remodeling TME to enable the tumoricidal roles of TAMs. Furthermore, we characterize TAM subgroups that determine the efficiency of lymphoma phagocytosis in the TME and can be potential therapeutic targets to unleash the antitumor activities of macrophages.

Cancer immunotherapies targeting adaptive immune checkpoints have substantially improved patient outcomes across multiple metastatic and treatment-refractory cancer types. However, emerging studies have demonstrated that innate immune checkpoints, which interfere with the detection and clearance of malignant cells through phagocytosis and suppress innate immune sensing, also have a key role in tumour-mediated immune escape and might, therefore, be potential targets for cancer immunotherapy. Indeed, preclinical studies and early clinical data have established the promise of targeting phagocytosis checkpoints, such as the CD47-signal-regulatory protein α (SIRPα) axis, either alone or in combination with other cancer therapies. In this Review, we highlight the current understanding of how cancer cells evade the immune system by disrupting phagocytic clearance and the effect of phagocytosis checkpoint blockade on induction of antitumour immune responses. Given the role of innate immune cells in priming adaptive immune responses, an improved understanding of the tumour-intrinsic processes that inhibit essential immune surveillance processes, such as phagocytosis and innate immune sensing, could pave the way for the development of highly effective combination immunotherapy strategies that modulate both innate and adaptive antitumour immune responses.

GABRR1 is a rho subunit receptor of GABA, the major inhibitory neurotransmitter in the mammalian brain. While most investigations of its function focused on the nervous system, its regulatory role in hematopoiesis has not been reported. In this study, we found GABRR1 is mainly expressed on subsets of human and mouse hematopoietic stem cells (HSCs) and megakaryocyte progenitors (MkPs). GABRR1-negative (GR-) HSCs led to higher donor-derived hematopoietic chimerism than GABRR1-positive (GR+) HSCs. GR+ but not GR- HSCs and MkPs respond to GABA in patch clamp studies. Inhibition of GABRR1 via genetic knockout or antagonists inhibited MkP differentiation and reduced platelet numbers in blood. Overexpression of GABRR1 or treatment with agonists significantly promoted MkP generation and megakaryocyte colonies. Thus, this study identifies a link between the neural and hematopoietic systems and opens up the possibility of manipulating GABA signaling for platelet-required clinical applications.

Cancer immunotherapy has revolutionized the paradigm for the clinical management of cancer. While FDA-approved cancer immunotherapies thus far mainly exploit the adaptive immunity for therapeutic efficacy, there is a growing appreciation for the importance of innate immunity in tumor cell surveillance and eradication. The past decade has witnessed macrophages being thrust into the spotlight as critical effectors of an innate anti-tumor response. Promising evidence from preclinical and clinical studies have established targeting macrophage phagocytosis as an effective therapeutic strategy, either alone or in combination with other therapeutic moieties. Here, we review the recent translational advances in harnessing macrophage phagocytosis as a pivotal therapeutic effort in cancer treatment. In addition, this review emphasizes phagocytosis checkpoint blockade and the use of nanoparticles as effective strategies to potentiate macrophages for phagocytosis. We also highlight chimeric antigen receptor macrophages as a next-generation therapeutic modality linking the closely intertwined innate and adaptive immunity to induce efficacious anti-tumor immune responses.

BackgroundLimited therapeutic options are available for triple-negative breast cancer (TNBC), emphasizing an urgent need for more effective treatment approaches. The development of strategies by targeting tumor-associated macrophages (TAMs) to stimulate their ability of Programmed Cell Removal (PrCR) provides a promising new immunotherapy for TNBC treatment.MethodsCD47 is a critical self-protective “don’t eat me” signal on multiple human cancers against macrophage immunosurveillance. Using human and mouse TNBC preclinical models, we evaluated the efficacy of PrCR-based immunotherapy by blocking CD47. We performed high-throughput screens on FDA-approved anti-cancer small molecule compounds for agents potentiating PrCR and enhancing the efficacy of CD47-targeted therapy for TNBC treatment.ResultsWe showed that CD47 was widely expressed on TNBC cells and TAMs represented the most abundant immune cell population in TNBC tumors. Blockade of CD47 enabled PrCR of TNBC cells, but the efficacy was not satisfactory. Our high-throughput screens identified cabazitaxel in enhancing PrCR-based immunotherapy. A combination of CD47 blockade and cabazitaxel treatment yielded a highly effective treatment strategy, promoting PrCR of TNBC cells and inhibiting tumor development and metastasis in preclinical models. We demonstrated that cabazitaxel potentiated PrCR by activating macrophages, independent of its cytotoxicity toward cancer cells. When treated with cabazitaxel, the molecular and phenotypic signatures of macrophages were polarized toward M1 state, and the NF-kB signaling pathway became activated.ConclusionThe combination of CD47 blockade and macrophage activation by cabazitaxel synergizes to vastly enhance the elimination of TNBC cells. Our results show that targeting macrophages is a promising and effective strategy for TNBC treatment.

Evasion of immunosurveillance is critical for cancer initiation and development. The expression of “don’t eat me” signals protects cancer cells from being phagocytosed by macrophages, and the blockade of such signals demonstrates therapeutic potential by restoring the susceptibility of cancer cells to macrophage-mediated phagocytosis. However, whether additional self-protective mechanisms play a role against macrophage surveillance remains unexplored. Here, we derived a macrophage-resistant cancer model from cells deficient in the expression of CD47, a major “don’t eat me” signal, via a macrophage selection assay. Comparative studies performed between the parental and resistant cells identified self-protective traits independent of CD47, which were examined with both pharmacological or genetic approaches in in vitro phagocytosis assays and in vivo tumor models for their roles in protecting against macrophage surveillance. Here we demonstrated that extracellular acidification resulting from glycolysis in cancer cells protected them against macrophage-mediated phagocytosis. The acidic tumor microenvironment resulted in direct inhibition of macrophage phagocytic ability and recruitment of weakly phagocytic macrophages. Targeting V-ATPase which transports excessive protons in cancer cells to acidify extracellular medium elicited a pro-phagocytic microenvironment with an increased ratio of M1-/M2-like macrophage populations, therefore inhibiting tumor development and metastasis. In addition, blockade of extracellular acidification enhanced cell surface exposure of CD71, targeting which by antibodies promoted cancer cell phagocytosis. Our results reveal that extracellular acidification due to the Warburg effect confers immune evasion ability on cancer cells. This previously unrecognized role highlights the components mediating the Warburg effect as potential targets for new immunotherapy harnessing the tumoricidal capabilities of macrophages.

Multiple myeloma (MM) is characterized by an accumulation of malignant plasma cells (PCs) within the BM. The BM microenvironment supports survival of the malignant cells and is composed of cellular fractions that foster myeloma development and progression by suppression of the immune response. Despite major progress in understanding the biology and pathophysiology of MM, this disease is still incurable and requires aggressive treatment with significant side effects. CD84 is a self-binding immunoreceptor belonging to the signaling lymphocyte activation molecule (SLAM) family. Previously, we showed that CD84 bridges between chronic lymphocytic leukemia cells and their microenvironment, and it regulates T cell function. In the current study, we investigated the role of CD84 in MM. Our results show that MM cells express low levels of CD84. However, these cells secrete the cytokine macrophage migration inhibitory factor (MIF), which induces CD84 expression on cells in their microenvironment. Its activation leads to an elevation of expression of genes regulating differentiation to monocytic/granulocytic-myeloid-derived suppressor cells (M-MDSCs and G-MDSCs, respectively) and upregulation of PD-L1 expression on MDSCs, which together suppress T cell function. Downregulation of CD84 or its blocking reduce MDSC accumulation, resulting in elevated T cell activity and reduced tumor load. Our data suggest that CD84 might serve as a novel therapeutic target in MM.

The cell surface proteome provides a pivotal interphase that connects the intracellular signaling with external environments, which may harbor molecular targets for therapeutic development. To identify essential cell surface proteins in cancers, we established a CRISPR library that contains 2,910 sgRNAs targeting 582 genes encoding cell surface receptors (to cytokines, extracellular matrices [ECM], etc.), molecular channels, and signaling components. We then screened this library in 3 solid cancer (MDA-MB-231, SW620, PANC1) and 3 liquid cancer (MV4-11, HUT78, CCRF-CEM) cell models expressing the Cas9 endonuclease, and observed an essential role of ITGAV (Integrin Alpha V) specifically in the solid cancer. As integrins require the dimerization between an alpha and beta subunit to function as cell surface ECM receptors, we further developed a focused CRISPR library with 650 sgRNAs targeting all 26 integrin alpha and beta subunits. This validation screen revealed a strong correlation between ITGAV and ITGB5 (Integrin Beta 5) in solid tumors. CRISPR targeting either ITGAV or ITGB5 led to attenuated cell proliferation with increased cell cycle stalling and apoptosis. Knockout of ITGAV-ITGB5 also suppressed the capacity of tumor cells to migrate and invade through the ECM, highlighting the therapeutic benefit via blocking the ITGAV-ITGB5 heterodimer. To identify novel compounds that can disrupt ITGAV-ITGB5 dimerization, we first modeled a 3D crystal structure of ITGAV (PDB ID: 3IJE) using AutoSite (Scripps) to reveal the protein surface pockets amenable to the small molecular binding. This analysis revealed an AVB pocket at the N-terminal extracellular domain of ITGAV, which is in close contact with the beta subunit. CRISPR targeting this AVB pocket abolished the ITGAV-ITGB5 heterodimers (detected by an AV-B5-complex antibody) and induced rapid cell death, rationalizing this pocket for further therapeutic development. Based on these observations, we computationally docked >100,000 compounds from the NCI DTP Open Chemicals Repository using AutoDock Vina (Scripps), subsequently obtaining the top 500 binder compounds for in-lab validation, and identified a lead AVB pocket inhibitor “Cpd_2” (C32H40N4). Treatment of Cpd_2 killed tumor cells and diminished the AV-B5-complex antibody stain. Furthermore, we confirmed the capacity of Cpd_2 to dissociate ITGAV and ITGB5 on the cell surface by a NanoBRET energy transfer system. Of note, while the traditional ITGAV inhibitor cilengitide (an RGD peptide mimic) blocked the ECM interaction and detached the cells from TC dishes, they failed to dissociate the ITGAV-ITGB5 heterodimer nor induce rapid cell death. In summary, our study highlights a novel strategy of targeting the ITGAV-ITGB5 heterodimer stability by the small molecular inhibitor Cpd_2 for future anti-tumor treatment. Citation Format: Nicole Mattson, Kazuya Miyashita, Anthony Chan, Lu Yang, Sheela Pangeni Pokharel, Wei Lu, Mingli Li, Qiao Liu, Xiaobao Xu, Mingye Feng, Chun-Wei Chen. Targeting integrin alpha V beta 5 heterodimer stability using a novel small molecular inhibitor for tumor suppression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2920.

Immune checkpoint (IC) blockade for programmed cell death 1 (PD1) and PD-Ligand 1 (PD-L1) has shown promising and durable therapeutic outcomes in cutaneous T-cell lymphoma (CTCL), but resistance and/or relapses are common. While research focused on improving adaptive immune functions in CTCL, we investigated the role of 1) the “do not eat me signal” (CD47), and PD-L1, as a dual (innate and adaptive IC)-targeting strategy in CTCL. RNA sequencing and flow cytometric analysis showed that CTCL tumor cells and CTCL cell lines (MyLa, Hut78, HH, and H9 cells) overexpressed CD47 and PD-L1 compared with healthy control, and CD47 positively correlated with PD-L1 in CTCL patients. Overexpression of CD47 and PD-L1 was induced by high MYC expression in CTCL tumor cells lines. In addition, the signal-regulatory protein (SIRP)α receptor for CD47 and PD-L1 were significantly more abundant on macrophages, dendritic cells and natural killer cells in CTCL patients than healthy control by flow cytometric analysis. Furthermore, the RNA sequencing data indicated that the M2 macrophages, immature dendritic cells, and inhibitory receptors expressed natural killer cells in CTCL patients were higher than in healthy control. Notably, TTI-621 (SIRPαFc) treatment decreased M2 macrophage, immature dendritic cells, and inhibitory receptors expressed natural killer cells in CTCL patients at the end of the treatment, compared to baseline. In vitro, TTI-621 treatment increased the macrophage phagocytic activity compared to untreated control. Moreover, TTI-621 synergized with an anti-PD-L1 antibody (durvalumab) to reprogram M2-like TAMs, induced by MyLa supernatant, to M1-like phenotypes. The simultaneous blockade of both CD47 and PD-L1 inhibited growth of CTCL cell lines more potently than each single antibody alone or blank control in vitro. Enhanced CD8+ T cell mediated killing was detected using a chromium-release assay following dual blockade of in CTCL cell lines, suggesting anti-CD47 and anti-PD-L1 may synergistically facilitate elimination of CTCL tumor cells through specific pathways. RNA-sequencing analysis indicated that these effects were mediated by cell death related pathways such as apoptosis, autophagy, and necroptosis. Collectively, our findings demonstrated that CD47 and PD-L1 are critical regulators of innate and adaptive immune surveillance in CTCL and that dual targeting of CD47 and PD-L1 will provide insight into tumor immunotherapy to improve tumor control in CTCL. Citation Format: Zhen Han, Mingye Feng, Xiwei Wu, Chingyu Su, Yate-Ching Yuan, Hanjun Qin, James F. Sanchez, Jasmine Zain, Steven T. Rosen, Christiane Querfeld. CD47 Blockade potentiates immunotherapy of durvalumab against cutaneous T cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5196.

The objective of this study was to evaluate the performance changes of three restorative materials before and after three different aging treatments: storage in distilled water, Streptococcus mutans (S. mutans) and oral salivary microbes suspensions for one month. Resin composite (RC), giomer and glass ionomer cement (GIC) were chosen for aging procedures. Surface morphology, roughness average (Ra), color changes and mechanical properties were all determined before and after aging respectively. Biomass and metabolism difference of early attached biofilm on the material surface were tested through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and lactic acid measurement. The results showed that after S. mutans or salivary microbes aging treatments, GIC group displayed significant morphology changes, with Ra value significantly higher than that before aging (p < .001). Color changes of giomer and GIC group after S. mutans aging were not clinically acceptable. All materials after two microbial-based aging treatments had higher flexural strength than that before aging (p < .05). Giomer after salivary microbes aging had higher elastic modulus than the initial values (p < .05). Additionally, early attached biofilm biomass and lactic acid production in GIC group after S. mutans or salivary microbes aging were higher than that before aging (p < .05). While one-month water aging showed less influences on material performance to some extent. In conclusion, to better simulate the harsh oral environment, in vitro microbial-based aging models showed more advantages in evaluating dental restorative materials' degradation over time.

Background: Tumor-associated macrophages (TAMs) play a key role in cutaneous T cell lymphoma (CTCL) growth and neoplastic T cells escape immune surveillance via PD1-PD-L1 axis (Querfeld, C., et al., Blood 2019; Khodadoust, M.S., et al., J Clin Oncol, 2020). There remains a lack of knowledge about how cytokines regulate the mechanisms controlling tumor-growth and polarize the tumor microenvironment (TME). Methods and Results: To investigate PD-L1 and PD1 expression on TAMs and T cells in mycosis fungoides (MF) and the leukemic variant Sézary syndrome (SS) patients, we performed multiplex immunofluorescence (IF) staining of lesional skin samples of MF patients that demonstrated co-localization of PD-L1 on CD163+ M2 macrophages and PD1 expression on CD4+ and CD8+ T cells. In addition, significant enrichment of CD14+ and CD16+/CD14dim CD163+ M2-like monocytes/macrophages with upregulated PD-L1 expression in SS patients compared to healthy donors (HDs) was found via FACS analysis. We also performed 30-plex Luminex cytokine assay on plasma samples, which showed significantly increased IL-6, IL-10, IFNγ and TNFα levels in plasma of MF/SS compared to HDs. To investigate whether polarization towards an M2-like macrophage phenotype with increased PD-L1 expression correlated with the cytokine expression from CTCL-TME, we cultured total PBMCs from HDs with conditioned media (CM) from well established CTCL cell lines MyLa and HuT78 and analyzed PD-L1 mRNA, total PD-L1 protein and PD-L1 surface expression on M2-like macrophages. Significantly increased expression of PD-L1 protein in total PBMCs, especially on CD14+ and CD16+/CD14dim M2-like macrophages was seen. To understand whether distinct cytokines are associated with PD-L1 upregulation on CD163+ M2-like populations, total PBMCs from HDs were stimulated with human recombinant IL-6, IL-10, IFNγ or TNFα. Antibody blocking studies were conducted by adding anti human IL-6, IL-10, IFNγ or TNFα to the cultures with CM. TNFα stimulation significantly increased the CD14+ M2-like subset, but did not affect CD16+/CD14dim M2-like subset. We observed increased PD-L1 expression on both M2-like populations with TNFα compared to other cytokines. In contrast, blockade of TNFα significantly decreased the CD14+ M2-like subset with reduced PD-L1 expression and increased CD16+/CD14dim M2-like cells with upregulated PD-L1 expression. To explore whether the STAT pathway regulates PD-L1 expression through cytokines from CTCL TME, we incubated total PBMCs from HDs in CM of MyLa and HuT78 cells with/without a pan-STAT inhibitor, and in media alone. Inhibition of STAT signaling decreased CD14+ M2-like macrophage population, but did not alter the CD16+/CD14dim M2-like population. In addition, pan-STAT inhibition significantly reduced surface expression of PD-L1 on both CD14+ and CD16+/CD14dim M2-like macrophages. The effects of cytokines on STAT signaling components in regulating PD-L1 expression were also investigated by FACS and immunoblots. TNFα blockade significantly downregulated PD-L1, but also pSTAT1, pSTAT3 and pNF-κB levels, illustrating the role of TNFα on STAT1, STAT3 and NF-κB pathways in conjunction with PD-L1 expression. Stimulation with TNFα increased pSTAT3 level in CD14+ M2-like macrophages, while it did not significantly change pSTAT3 in CD16+/CD14dim M2-like macrophages. Anti-TNFα reduced pSTAT3 levels in CD14+ M2-like macrophages, but profoundly increased PD-L1 in CD16+/CD14dim M2-like macrophages, which aligns with our data of increased PD-L1 expression on CD16+/CD14dim M2-like macrophages following TNFα blockade. Conclusion: We profiled immune alterations of monocyte/macrophages populations and PD-L1 expression in CTCL regulated by selected cytokines. Our results support the dominant role of TNFα in the CTCL microenvironment. Here we show that TNFα potentiates the immunosuppressive TME through macrophage polarization and STAT-mediated PD-L1 regulation. Our results identify potential targets for combination immunotherapy. Disclosures Zain: Seattle Genetics: Research Funding; Mundai Pharma: Research Funding; Kyowa Kirlin: Research Funding. Abdulla:Johnson Johnson: Research Funding; Mallinckrodt: Consultancy, Speakers Bureau. Rosen:Seattle Genetics: Consultancy; NeoGenomics: Consultancy; Aileron Therapeutics: Consultancy; Novartis: Consultancy; Pebromene: Consultancy; Celgene: Speakers Bureau; Abbvie: Speakers Bureau; paradigm Medical Communications: Speakers Bureau. Querfeld:Trillium: Consultancy; Stemline: Consultancy; Bioniz: Consultancy; Helsinn: Consultancy; Celgene: Research Funding; Kyowa Kirin: Consultancy; MiRagen: Consultancy.

East Asia is characterized by an east-west topographic dichotomy on the two sides of the North-South Gravity Lineament (NSGL), a feature not associated with major basement boundaries. The NSGL also marks an abrupt change in the thickness of the continental crust and the lithospheric mantle, as well as that in the associated residual topography. Both the mechanism and timing for the formation of this unique East Asian lithospheric property remain unclear. We reviewed the key tectonic records of East Asia since the early Mesozoic, with a particular focus on the plausible underlying mantle dynamics. The observation that widespread Jurassic-Early Cretaceous crustal extension occurred on both sides of the NSGL and that Cenozoic rift basins were predominantly to the east of the NSGL suggests that the seismically observed East Asian lithospheric structure came into being no earlier than the Cretaceous. Several flat-slab models have been proposed. We suggest that a combination of these models could explain the unique East Asian lithospheric evolution since the Middle Mesozoic. Further ground truth using quantitative geodynamic models with data assimilation demonstrates that a flat slab could significantly reduce the thickness of the overriding plate by dislocating and entraining the lower mantle lithosphere. Meanwhile, an advancing flat slab causes widespread upper-lithosphere compression and disappearance of the mantle wedge, implying regional-scale surface uplift (or reduced subsidence) and magmatic quiescence, respectively. We identify two episodes of Mesozoic flat slabs below East Asia, one during the Jurassic-Early Cretaceous and the other during the Late Cretaceous. The former affected the eastern half of North China and Northeast China, and the latter affected the entire region east of the NSGL from Northeast China to South China. These two flat-slab cycles largely determined the evolution of the lithosphere and topography within East Asia since the Mesozoic.

// Wang Gong 1 , Yandi Xiao 1 , Zihao Wei 1 , Yao Yuan 1 , Min Qiu 1 , Chongkui Sun 1 , Xin Zeng 1 , Xinhua Liang 1 , Mingye Feng 1 and Qianming Chen 1 1 State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China Correspondence to: Mingye Feng, email: // Keywords : big data, precision medicine, targeted therapy, gene therapy, HNSCC Received : April 22, 2016 Accepted : November 21, 2016 Published : December 04, 2016 Abstract Precision medicine is a new strategy that aims at preventing and treating human diseases by focusing on individual variations in people’s genes, environment and lifestyle. Precision medicine has been used for cancer diagnosis and treatment and shows evident clinical efficacy. Rapid developments in molecular biology, genetics and sequencing technologies, as well as computational technology, has enabled the establishment of “big data”, such as the Human Genome Project, which provides a basis for precision medicine. Head and neck squamous cell carcinoma (HNSCC) is an aggressive cancer with a high incidence rate and low survival rate. Current therapies are often aggressive and carry considerable side effects. Much research now indicates that precision medicine can be used for HNSCC and may achieve improved results. From this perspective, we present an overview of the current status, potential strategies, and challenges of precision medicine in HNSCC. We focus on targeted therapy based on cell the surface signaling receptors epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF) and human epidermal growth factor receptor-2 (HER2), and on the PI3K/AKT/mTOR, JAK/STAT3 and RAS/RAF/MEK/ERK cellular signaling pathways. Gene therapy for the treatment of HNSCC is also discussed.

// Xiaoyan Xie 1, * , Yuchen Jiang 1, * , Yao Yuan 1, * , Peiqi Wang 1 , Xinyi Li 1 , Fangman Chen 1 , Chongkui Sun 1 , Hang Zhao 1 , Xin Zeng 1 , Lu Jiang 1 , Yu Zhou 1 , Hongxia Dan 1 , Mingye Feng 1 , Rui Liu 1 , Qianming Chen 1 1 State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China * These authors have contributed equally to this work Correspondence to: Rui Liu, email: liurui_scu@hotmail.com Qianming Chen, email: qmchen@scu.edu.cn Keywords: NCOA7, MALDI Imaging, oral squamous cell carcinoma, oral submucous fibrosis, aryl hydrocarbon receptor Received: December 14, 2015 Accepted: June 09, 2016 Published: August 4, 2016 ABSTRACT Oral squamous cell carcinoma (OSCC) ranks among the most common cancer worldwide, and is associated with severe morbidity and high mortality. Oral submucous fibrosis (OSF), characterized by fibrosis of the mucosa of the upper digestive tract, is a pre-malignant lesion, but the molecular mechanisms underlying this malignant transformation remains to be elucidated. In this study, matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS)-based proteomic strategy was employed to profile the differentially expressed peptides/proteins between OSCC tissues and the corresponding adjacent non-cancerous OSF tissues. Sixty-five unique peptide peaks and nine proteins were identified with altered expression levels. Of them, expression of NCOA7 was found to be up-regulated in OSCC tissues by immunohistochemistry staining and western blotting, and correlated with a pan of clinicopathologic parameters, including lesion site, tumor differentiation status and lymph node metastasis. Further, we show that overexpression of NCOA7 promotes OSCC cell proliferation in either in vitro or in vivo models. Mechanistic study demonstrates that NCOA7 induces OSCC cell proliferation probably by activating aryl hydrocarbon receptor (AHR). The present study suggests that NCOA7 is a potential biomarker for early diagnosis of OSF malignant transformation, and leads to a better understanding of the molecular mechanisms responsible for OSCC development.

Background 5-Fluorouracil (5-FU) is an essential chemotherapeutic agent for oral squamous cell carcinoma (OSCC). However, toxic side effects have limited its role in OSCC therapy. The aim of this study was to explore whether combination therapy with 5-FU and honokiol (HNK), a small natural organic molecule shown to induce apoptosis in OSCC cells, could enhance the anticancer activity of 5-FU without notably increasing its toxicity. Methods 5-FU and/or HNK were used to treat OSCC cells both in vitro and in vivo. The therapeutic effect and underlying mechanisms were evaluated by cell viability assay, flow cytometry, OSCC xenograft mouse model, and Western blot. Tumor tissue apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Toxicity was assessed following hematoxylin and eosin staining. Results Exposure to HNK + 5-FU produced a synergistic cytotoxic effect on OSCC cells. Both HNK and 5-FU could induce apoptosis through the mitochondria-mediated intrinsic pathway, and their specific signaling pathways were different. In the mouse OSCC xenograft model, treatment with 5-FU + HNK substantively retarded tumor growth, as compared to treatment with either drug individually. TUNEL analysis further confirmed that the superior in vivo antitumor efficacy of 5-FU + HNK was associated with enhanced stimulation of cell apoptosis. Notably, HNK did not increase the toxicity of 5-FU. Conclusion These findings suggest that HNK and 5-FU exert a synergistic therapeutic effect on OSCC by inducing apoptosis. HNK might thus enhance the clinical therapeutic efficacy of 5-FU without increasing its toxicity.

PURPOSE OF REVIEW: To describe the relevance of CD47 in the tumor microenvironment and summarize data on anti-CD47 therapies, including its role in cutaneous T-cell lymphoma (CTCL). RECENT FINDINGS: CD47 is expressed on all normal cells and targets SIRPα on the surface of myeloid cells. However, CD47 is found to be overexpressed on cancer cells. CD47-SIRPα interaction inhibits macrophage phagocytosis, allowing cancer cells to escape immune surveillance. Current focus in immunotherapy has been targeted towards inhibiting CD47-SIRPα interaction via anti-CD47 antibodies. This activates innate immunity, promoting cancer cell destruction by macrophages. It also activates adaptive immunity resulting in antigen-presentation, mostly by dendritic cells, leading to anti-tumor cytotoxic reactions. Current CD47 antagonists undergoing clinical trials include Hu5F9 (an anti-CD47 antibody that directly inhibits the CD47-SIRPα interaction) and TTI-621, (a fusion protein composed of CD47 binding domain of human SIRPα and linked to the Fc region of IgG1). These agents have continued to show strong efficacy against solid and hematological tumors. SUMMARY: In the CTCL tumor microenvironment, increased immune checkpoint inhibition expression via CD47 bound to SIRPα correlates with a more advanced disease state. Continued success in treating these patients require further studies on CD47 antagonists, specifically when combined with other antibodies.