Biological insights from plasma proteomics of non-small cell lung cancer patients treated with immunotherapy.

Introduction: Immune checkpoint inhibitors have made a paradigm shift in the treatment of non-small cell lung cancer (NSCLC). However, clinical response varies widely and robust predictive biomarkers for patient stratification are lacking. Here, we characterize early on-treatment proteomic changes in blood plasma to gain a better understanding of treatment response and resistance. Methods: Pre-treatment (T0) and on-treatment (T1) plasma samples were collected from 225 NSCLC patients receiving PD-1/PD-L1 inhibitor-based regimens. Plasma was profiled using aptamer-based technology to quantify approximately 7000 plasma proteins per sample. Proteins displaying significant fold changes (T1:T0) were analyzed further to identify associations with clinical outcomes using clinical benefit and overall survival as endpoints. Bioinformatic analyses of upregulated proteins were performed to determine potential cell origins and enriched biological processes. Results: The levels of 142 proteins were significantly increased in the plasma of NSCLC patients following ICI-based treatments. Soluble PD-1 exhibited the highest increase, with a positive correlation to tumor PD-L1 status, and, in the ICI monotherapy dataset, an association with improved overall survival. Bioinformatic analysis of the ICI monotherapy dataset revealed a set of 30 upregulated proteins that formed a single, highly interconnected network, including CD8A connected to ten other proteins, suggestive of T cell activation during ICI treatment. Notably, the T cell-related network was detected regardless of clinical benefit. Lastly, circulating proteins of alveolar origin were identified as potential biomarkers of limited clinical benefit, possibly due to a link with cellular stress and lung damage. Conclusions: Our study provides insights into the biological processes activated during ICI-based therapy, highlighting the potential of plasma proteomics to identify mechanisms of therapy resistance and biomarkers for outcome.

Interferon-stimulated neutrophils as a predictor of immunotherapy response.

Despite the remarkable success of anti-cancer immunotherapy, its effectiveness remains confined to a subset of patients-emphasizing the importance of predictive biomarkers in clinical decision-making and further mechanistic understanding of treatment response. Current biomarkers, however, lack the power required to accurately stratify patients. Here, we identify interferon-stimulated, Ly6Ehi neutrophils as a blood-borne biomarker of anti-PD1 response in mice at baseline. Ly6Ehi neutrophils are induced by tumor-intrinsic activation of the STING (stimulator of interferon genes) signaling pathway and possess the ability to directly sensitize otherwise non-responsive tumors to anti-PD1 therapy, in part through IL12b-dependent activation of cytotoxic T cells. By translating our pre-clinical findings to a cohort of patients with non-small cell lung cancer and melanoma (n = 109), and to public data (n = 1440), we demonstrate the ability of Ly6Ehi neutrophils to predict immunotherapy response in humans with high accuracy (average AUC ≈ 0.9). Overall, our study identifies a functionally active biomarker for use in both mice and humans.

The role of host response to chemotherapy: resistance, metastasis and clinical implications.

Chemotherapy remains the primary treatment for most metastatic cancers. However, the response to chemotherapy and targeted agents is often transient, and concurrent development of resistance is the primary impediment to effective cancer therapy. Strategies to overcome resistance to treatment have focused on cancer cell intrinsic factors and the tumor microenvironment (TME). Recent evidence indicates that systemic chemotherapy has a significant impact on the host that either facilitates tumor growth, allowing metastatic spread, or renders treatment ineffective. These host responses include the release of bone marrow-derived cells, activation of stromal cells in the TME, and induction of different molecular effectors. Here, we provide an overview of chemotherapy-induced systemic host responses that support tumor aggressiveness and metastasis, and which contribute to therapy resistance. Studying host responses to chemotherapy provides a solid basis for the development of adjuvant strategies to improve treatment outcomes and delay resistance to chemotherapy. This review discusses the emerging field of host response to cancer therapy, and its preclinical and potential clinical implications, explaining how under certain circumstances, these host effects contribute to metastasis and resistance to chemotherapy.

Oncogenic ASPM Is a Regulatory Hub of Developmental and Stemness Signaling in Cancers.

Despite recent advances in molecularly targeted therapies and immunotherapies, the effective treatment of advanced-stage cancers remains a largely unmet clinical need. Identifying driver mechanisms of cancer aggressiveness can lay the groundwork for the development of breakthrough therapeutic strategies. Assembly factor for spindle microtubules (ASPM) was initially identified as a centrosomal protein that regulates neurogenesis and brain size. Mounting evidence has demonstrated the pleiotropic roles of ASPM in mitosis, cell-cycle progression, and DNA double-strand breaks (DSB) repair. Recently, the exon 18-preserved isoform 1 of ASPM has emerged as a critical regulator of cancer stemness and aggressiveness in various malignant tumor types. Here, we describe the domain compositions of ASPM and its transcript variants and overview their expression patterns and prognostic significance in cancers. A summary is provided of recent progress in the molecular elucidation of ASPM as a regulatory hub of development- and stemness-associated signaling pathways, such as the Wnt, Hedgehog, and Notch pathways, and of DNA DSB repair in cancer cells. The review emphasizes the potential utility of ASPM as a cancer-agnostic and pathway-informed prognostic biomarker and therapeutic target.

Chemotherapy-induced tumor immunogenicity is mediated in part by megakaryocyte-erythroid progenitors.

Chemotherapy remains one of the main treatment modalities for cancer. While chemotherapy is mainly known for its ability to kill tumor cells directly, accumulating evidence indicates that it also acts indirectly by enhancing T cell-mediated anti-tumor immunity sometimes through immunogenic cell death. However, the role of immature immune cells in chemotherapy-induced immunomodulation has not been studied. Here, we utilized a mouse pancreatic cancer model to characterize the effects of gemcitabine chemotherapy on immature bone marrow cells in the context of tumor immunogenicity. Single cell RNA sequencing of hematopoietic stem and progenitor cells revealed a 3-fold increase in megakaryocyte-erythroid progenitors (MEPs) in the bone marrow of gemcitabine-treated mice in comparison to untreated control mice. Notably, adoptive transfer of MEPs to pancreatic tumor-bearing mice significantly reduced tumor growth and increased the levels of anti-tumor immune cells in tumors and peripheral blood. Furthermore, MEPs increased the tumor cell killing activity of CD8 + T cells and NK cells, an effect that was dependent on MEP-secreted CCL5 and CXCL16. Collectively, our findings demonstrate that chemotherapy-induced enrichment of MEPs in the bone marrow compartment contributes to anti-tumor immunity.

RNF4~RGMb~BMP6 axis required for osteogenic differentiation and cancer cell survival.

Molecular understanding of osteogenic differentiation (OD) of human bone marrow-derived mesenchymal stem cells (hBMSCs) is important for regenerative medicine and has direct implications for cancer. We report that the RNF4 ubiquitin ligase is essential for OD of hBMSCs, and that RNF4-deficient hBMSCs remain as stalled progenitors. Remarkably, incubation of RNF4-deficient hBMSCs in conditioned media of differentiating hBMSCs restored OD. Transcriptional analysis of RNF4-dependent gene signatures identified two secreted factors that act downstream of RNF4 promoting OD: (1) BMP6 and (2) the BMP6 co-receptor, RGMb (Dragon). Indeed, knockdown of either RGMb or BMP6 in hBMSCs halted OD, while only the combined co-addition of purified RGMb and BMP6 proteins to RNF4-deficient hBMSCs fully restored OD. Moreover, we found that the RNF4-RGMb-BMP6 axis is essential for survival and tumorigenicity of osteosarcoma and therapy-resistant melanoma cells. Importantly, patient-derived sarcomas such as osteosarcoma, Ewing sarcoma, liposarcomas, and leiomyosarcomas exhibit high levels of RNF4 and BMP6, which are associated with reduced patient survival. Overall, we discovered that the RNF4~BMP6~RGMb axis is required for both OD and tumorigenesis.

Bv8 Blockade Sensitizes Anti-PD1 Therapy Resistant Tumors.

Myeloid-derived suppressor cells (MDSCs) are known to promote tumor growth in part by their immunosuppressive activities and their angiogenesis support. It has been shown that Bv8 blockade inhibits the recruitment of MDSCs to tumors, thereby delaying tumor relapse associated with resistance to antiangiogenic therapy. However, the impact of Bv8 blockade on tumors resistant to the new immunotherapy drugs based on the blockade of immune checkpoints has not been investigated. Here, we demonstrate that granulocytic-MDSCs (G-MDSCs) are enriched in anti-PD1 resistant tumors. Importantly, resistance to anti-PD1 monotherapy is reversed upon switching to a combined regimen comprised of anti-Bv8 and anti-PD1 antibodies. This effect is associated with a decreased level of G-MDSCs and enrichment of active cytotoxic T cells in tumors. The blockade of anti-Bv8 has shown efficacy also in hyperprogressive phenotype of anti-PD1-treated tumors. In vitro, anti-Bv8 antibodies directly inhibit MDSC-mediated immunosuppression, as evidenced by enhanced tumor cell killing activity of cytotoxic T cells. Lastly, we show that anti-Bv8-treated MDSCs secrete proteins associated with effector immune cell function and T cell activity. Overall, we demonstrate that Bv8 blockade inhibits the immunosuppressive function of MDSCs, thereby enhancing anti-tumor activity of cytotoxic T cells and sensitizing anti-PD1 resistant tumors. Our findings suggest that combining Bv8 blockade with anti-PD1 therapy can be used as a strategy for overcoming therapy resistance.

Longitudinal plasma proteomic profiling of patients with non-small cell lung cancer undergoing immune checkpoint blockade.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have revolutionized the cancer therapy landscape due to long-term benefits in patients with advanced metastatic disease. However, robust predictive biomarkers for response are still lacking and treatment resistance is not fully understood. METHODS: We profiled approximately 800 pre-treatment and on-treatment plasma proteins from 143 ICI-treated patients with non-small cell lung cancer (NSCLC) using ELISA-based arrays. Different clinical parameters were collected from the patients including specific mutations, smoking habits, and body mass index, among others. Machine learning algorithms were used to identify a predictive signature for response. Bioinformatics tools were used for the identification of patient subtypes and analysis of differentially expressed proteins and pathways in each response group. RESULTS: We identified a predictive signature for response to treatment comprizing two proteins (CXCL8 and CXCL10) and two clinical parameters (age and sex). Bioinformatic analysis of the proteomic profiles identified three distinct patient clusters that correlated with multiple parameters such as response, sex and TNM (tumors, nodes, and metastasis) staging. Patients who did not benefit from ICI therapy exhibited significantly higher plasma levels of several proteins on-treatment, and enrichment in neutrophil-related proteins. CONCLUSIONS: Our study reveals potential biomarkers in blood plasma for predicting response to ICI therapy in patients with NSCLC and sheds light on mechanisms underlying therapy resistance.

Photopharmacological modulation of native CRAC channels using azoboronate photoswitches.

SignificanceCalcium release-activated calcium (CRAC) channels play key roles in the regulation of cellular signaling, transcription, and migration. Here, we describe the design, chemical synthesis, and characterization of photoswitchable channel inhibitors that can be switched on and off depending on the wavelength of light used. We use the compounds to induce light-dependent modulation of channel activity and downstream gene expression in human immune cells. We further expand the usage of the compounds to control seeding of cancer cells in target tissue and regulation of response to noxious stimuli in vivo in mice.

T Cells Promote Metastasis by Regulating Extracellular Matrix Remodeling following Chemotherapy.

Metastasis is the main cause of cancer-related mortality. Despite intense efforts to understand the mechanisms underlying the metastatic process, treatment of metastatic cancer is still challenging. Here we describe a chemotherapy-induced, host-mediated mechanism that promotes remodeling of the extracellular matrix (ECM), ultimately facilitating cancer cell seeding and metastasis. Paclitaxel (PTX) chemotherapy enhanced rapid ECM remodeling and mechanostructural changes in the lungs of tumor-free mice, and the protein expression and activity of the ECM remodeling enzyme lysyl oxidase (LOX) increased in response to PTX. A chimeric mouse model harboring genetic LOX depletion revealed chemotherapy-induced ECM remodeling was mediated by CD8+ T cells expressing LOX. Consistently, adoptive transfer of CD8+ T cells, but not CD4+ T cells or B cells, from PTX-treated mice to naïve immunodeprived mice induced pulmonary ECM remodeling. Lastly, in a clinically relevant metastatic breast carcinoma model, LOX inhibition counteracted the metastasis-promoting, ECM-related effects of PTX. This study highlights the role of immune cells in regulating ECM and metastasis following chemotherapy, suggesting that inhibiting chemotherapy-induced ECM remodeling represents a potential therapeutic strategy for metastatic cancer. SIGNIFICANCE: Chemotherapy induces prometastatic pulmonary ECM remodeling by upregulating LOX in T cells, which can be targeted with LOX inhibitors to suppress metastasis.See related commentary by Kolonin and Woodward, p. 197.

Six-Month Efficacy and Toxicity Profile of BNT162b2 Vaccine in Cancer Patients with Solid Tumors.

We had previously reported short-term efficacy, immunogenicity, and safety of the BNT162b2 vaccine among cancer patients with solid tumors. We aimed to evaluate these outcomes at six months postvaccination. The study cohort comprised patients who were on treatment during vaccination and throughout six months postvaccination. Serologic tests were performed after second vaccination and six months afterward. An age-matched cohort of health care workers served as controls. Documentation of COVID-19 infection, blood tests, and imaging studies during the study period was reviewed. Participants included 154 patients and 135 controls. Six months postvaccination, 122 (79%) patients were seropositive compared with 114 (84%) controls (P = 0.32). Serology titer dramatically decreased in a similar manner in both cohorts. No COVID-19 cases were documented in controls, and one case occurred in patient cohort. All previously reported adverse effects resolved. Taken together, the pattern of immunogenicity, efficacy, and safety of BNT162b2 in patients with cancer with solid tumors at six months postvaccination resembles that of the general population. SIGNIFICANCE: Evidence regarding efficacy and safety of COVID-19 vaccines in patients with cancer indicate a favorable short-term profile. Immunomodulation due to anticancer treatments may affect immunity and immunogenicity of patients with cancer to the BNT162b2 vaccine over time. Our study sheds light on these long-term outcomes and portrays a trend that resembles the general population.This article is highlighted in the In This Issue feature, p. 2355.

IL-6 contributes to metastatic switch via the differentiation of monocytic-dendritic progenitors into prometastatic immune cells.

BACKGROUND: Metastasis is the major cause of death in patients with cancer. Myeloid skewing of hematopoietic cells is a prominent promoter of metastasis. However, the reservoir of these cells in the bone marrow (BM) compartment and their differentiation pattern from hematopoietic stem and progenitor cells (HSPCs) have not been explored. METHODS: We used a unique model system consisting of tumor cell clones with low metastatic potential or high metastatic potential (met-low and met-high, respectively) to investigate the fate of HSPC differentiation using murine melanoma and breast carcinoma. Single-cell RNA sequencing (scRNA-seq) analysis was performed on HSPC obtained from the BM of met-low and met-high tumors. A proteomic screen of tumor-conditioned medium integrated with the scRNA-seq data analysis was performed to analyze the potential cross talk between cancer cells and HSPCs. Adoptive transfer of tumor-educated HSPC subsets obtained from green fluorescent protein (GFP)+ tagged mice was then carried out to identify the contribution of committed HSPCs to tumor spread. Peripheral mononuclear cells obtained from patients with breast and lung cancer were analyzed for HSPC subsets. RESULTS: Mice bearing met-high tumors exhibited a significant increase in the percentage of HSPCs in the BM in comparison with tumor-free mice or mice bearing met-low tumors. ScRNA-seq analysis of these HSPCs revealed that met-high tumors enriched the monocyte-dendritic progenitors (MDPs) but not granulocyte-monocyte progenitors (GMPs). A proteomic screen of tumor- conditioned medium integrated with the scRNA-seq data analysis revealed that the interleukin 6 (IL-6)-IL-6 receptor axis is highly active in HSPC-derived MDP cells. Consequently, loss of function and gain of function of IL-6 in tumor cells resulted in decreased and increased metastasis and corresponding MDP levels, respectively. Importantly, IL-6-educated MDPs induce metastasis within mice bearing met-low tumors-through further differentiation into immunosuppressive macrophages and not dendritic cells. Consistently, MDP but not GMP levels in peripheral blood of breast and lung cancer patients are correlated with tumor aggressiveness. CONCLUSIONS: Our study reveals a new role for tumor-derived IL-6 in hijacking the HSPC differentiation program toward prometastatic MDPs that functionally differentiate into immunosuppressive monocytes to support the metastatic switch.

Metronomic Chemotherapy Modulates Clonal Interactions to Prevent Drug Resistance in Non-Small Cell Lung Cancer.

Despite recent advances in deciphering cancer drug resistance mechanisms, relapse is a widely observed phenomenon in advanced cancers, mainly due to intratumor clonal heterogeneity. How tumor clones progress and impact each other remains elusive. In this study, we developed 2D and 3D non-small cell lung cancer co-culture systems and defined a phenomenological mathematical model to better understand clone dynamics. Our results demonstrated that the drug-sensitive clones inhibit the proliferation of the drug-resistant ones under untreated conditions. Model predictions and their experimental in vitro and in vivo validations indicated that a metronomic schedule leads to a better regulation of tumor cell heterogeneity over time than a maximum-tolerated dose schedule, while achieving control of tumor progression. We finally showed that drug-sensitive and -resistant clones exhibited different metabolic statuses that could be involved in controlling the intratumor heterogeneity dynamics. Our data suggested that the glycolytic activity of drug-sensitive clones could play a major role in inhibiting the drug-resistant clone proliferation. Altogether, these computational and experimental approaches provide foundations for using metronomic therapy to control drug-sensitive and -resistant clone balance and highlight the potential of targeting cell metabolism to manage intratumor heterogeneity.

Host response to immune checkpoint inhibitors contributes to tumor aggressiveness.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have made a paradigm shift in clinical oncology due to unprecedented long-term remissions. However, only a small proportion of patients respond to ICI therapy. It is, therefore, essential to understand the mechanisms driving therapy resistance and to develop strategies for increasing response rates. We previously demonstrated that in response to various cancer treatment modalities, the host activates a range of biological processes that promote tumor regrowth and metastasis. Here, we characterize the host-mediated response to ICI therapy, and investigate its contribution to therapy resistance. METHODS: Tumor cell migration, invasion and motility were assessed in the presence of plasma from ICI-treated mice and patients. Immune cell composition in peripheral blood and tumors of ICI-treated mice was assessed by flow and mass cytometry. Plasma host factors driving tumor aggressiveness were identified by proteomic profiling, followed by bioinformatic analysis. The therapeutic effect of inhibiting host-mediated processes in ICI-treated mice was assessed in a tumor model. RESULTS: Tumor cells exhibit enhanced migratory and invasive properties in vitro on exposure to plasma from anti-PD1-treated mice. Moreover, mice intravenously injected with plasma-exposed tumor cells display increased metastatic burden and mortality rate in comparison to control arms. Furthermore, tumors from anti-PD1-treated mice as well as Matrigel plugs containing plasma from anti-PD1-treated mice are highly infiltrated with immune cell types associated with both antitumor and protumor activity. These collective findings suggest that anti-PD1 treatment induces a systemic host response that potentially counteracts the drug's therapeutic activity. Proteomic profiling of plasma from anti-PD1-treated mice reveals an activation of multiple biological pathways associated with tumor aggressiveness. Consequently, blocking IL-6, one of the key drivers of the identified biological pathways, counteracts ICI-induced metastatic properties in vitro and improves ICI treatment efficacy in vivo. Lastly, plasma samples from ICI-treated non-small cell lung cancer patients differentially affect tumor cell aggressiveness in vitro, with enhanced tumor cell motility correlating with a worse clinical outcome. CONCLUSIONS: ICI therapy induces host-mediated processes that contribute to therapy resistance. Identification and analysis of such processes may lead to the discovery of biomarkers for clinical response and strategies for overcoming therapy resistance.

The Dichotomous Role of Bone Marrow Derived Cells in the Chemotherapy-Treated Tumor Microenvironment.

Bone marrow derived cells (BMDCs) play a wide variety of pro- and anti-tumorigenic roles in the tumor microenvironment (TME) and in the metastatic process. In response to chemotherapy, the anti-tumorigenic function of BMDCs can be enhanced due to chemotherapy-induced immunogenic cell death. However, in recent years, a growing body of evidence suggests that chemotherapy or other anti-cancer drugs can also facilitate a pro-tumorigenic function in BMDCs. This includes elevated angiogenesis, tumor cell proliferation and pro-tumorigenic immune modulation, ultimately contributing to therapy resistance. Such effects do not only contribute to the re-growth of primary tumors but can also support metastasis. Thus, the delicate balance of BMDC activities in the TME is violated following tumor perturbation, further requiring a better understanding of the complex crosstalk between tumor cells and BMDCs. In this review, we discuss the different types of BMDCs that reside in the TME and their activities in tumors following chemotherapy, with a major focus on their pro-tumorigenic role. We also cover aspects of rationally designed combination treatments that target or manipulate specific BMDC types to improve therapy outcomes.

Breast Cancer-Derived Microparticles Reduce Cancer Cell Adhesion, an Effect Augmented by Chemotherapy.

Tumor cell heterogeneity is primarily dictated by mutational changes, sometimes leading to clones that undergo a metastatic switch. However, little is known about tumor heterogeneity following chemotherapy perturbation. Here we studied the possible involvement of tumor-derived extracellular vesicles, often referred to as tumor-derived microparticles (TMPs), as mediators of the metastatic switch in the tumor microenvironment by hindering cell adhesion properties. Specifically, we show that highly metastatic or chemotherapy-treated breast cancer cells shed an increased number of TMPs compared to their respective controls. We found that these TMPs substantially reduce cell adhesion and disrupt actin filament structure, therefore increasing their biomechanical force pace, further implicating tumor cell dissemination as part of the metastatic cascade. Our results demonstrate that these pro-metastatic effects are mediated in part by CD44 which is highly expressed in TMPs obtained from highly metastatic cells or cells exposed to chemotherapy when compared to cells with low metastatic potential. Consequently, when we inhibited CD44 expression on TMPs by a pharmacological or a genetic approach, increased tumor cell adhesion and re-organized actin filament structure were observed. We also demonstrated that breast cancer patients treated with paclitaxel chemotherapy exhibited increased CD44-expressing TMPs. Overall, our study provides further insights into the role of TMPs in promoting metastasis, an effect which is augmented when tumor cells are exposed to chemotherapy.

Intratumoral HLA-DR-/CD33+/CD11b+ Myeloid-Derived Suppressor Cells Predict Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer.

Capecitabine-based neoadjuvant chemoradiation therapy (nCRT) is currently the mainstay of treatment for locally advanced rectal cancer (LARC), prior to surgical tumor removal. While response to this treatment is partial, it carries significant risk of side effects. As of today, there is no accepted model to predict tumor response, and allow for patient stratification. The level of circulating Myeloid-derived suppressor cells (MDSCs), a subpopulation of early myeloid cells (EMCs), has been shown to correlate with prognosis and response to therapy in advanced colon cancer, but their role in LARC is not clear. We sought to study the effect of intratumoral and circulating levels of different EMCs subpopulations including MDSCs on response to nCRT. We analyzed tumor, normal mucosa, and peripheral blood samples from 25 LARC patients for their different EMCs subpopulation before and after nCRT, and correlated them with degree of pathologic response, as determined postoperatively. In addition, we compared LARC patient to 10 healthy donors and 6 metastatic patients. CD33+HLA-DR-CD16-CD11b+EMCs in the circulation of LARC patients were found to inhibit T-cell activation. Furthermore, elevated levels of CD33+HLA-DR- myeloid cells were found in the tumor relative to normal mucosa, but not in the circulation when compared to healthy subjects. Moreover, intratumoral, but not circulating levels of MDSCs correlated with clinical stage and response to therapy in patients treated with nCRT, with high levels of MDSCs significantly predicting poor response to nCRT. Importantly, therapy by itself, had significant differential effects on MDSC levels, leading to increased circulating MDSCs, concomitantly with decreasing intratumoral MDSCs. Our results suggest that high levels of intratumoral, but not circulating MDSCs may confer drug resistance due to immunomodulatory effects, and serve as a biomarker for patient stratification and decision-making prior to nCRT.

IL-31 induces antitumor immunity in breast carcinoma.

BACKGROUND: Immunomodulatory agents that induce antitumor immunity have great potential for treatment of cancer. We have previously shown that interleukin (IL)-31, a proinflammatory cytokine from the IL-6 family, acts as an antiangiogenic agent. Here, we characterize the immunomodulatory effect of IL-31 in breast cancer. METHODS: In vivo breast carcinoma models including EMT6 and PyMT cell lines were used to analyze the effect of IL-31 on the composition of various immune cells in the tumor microenvironment using high-throughput flow cytometry. In vitro studies using isolated cytotoxic T cells, CD4+ T cells, myeloid-derived suppressor cells (MDSCs) and macrophages were carried out to study IL-31 immunological activity. The generation of recombinant IL-31 bound to IgG backbone was used to test IL-31 therapeutic activity. RESULTS: The growth rate of IL-31-expressing breast carcinomas is decreased in comparison with control tumors due, in part, to antitumor immunomodulation. Specifically, cytotoxic T cell activity is increased, whereas the levels of CD4+ T cells, MDSCs, and tumor-associated macrophages are decreased in IL-31-expressing tumors. These cellular changes are accompanied by a cytokine profile associated with antitumor immunity. In vitro, IL-31 directly inhibits CD4+ Th0 cell proliferation, and the expression of Th2 canonical factors GATA3 and IL-4. It also promotes CD8+ T cell activation through inhibition of MDSC activity and motility. Clinically, in agreement with the mouse data, alterations in immune cell composition in human breast cancer biopsies were found to correlate with high expression of IL-31 receptor A (IL-31Ra) . Furthermore, high coexpression of IL-31Ra, IL-2 and IL-4 in tumors correlates with increased survival. Lastly, to study the therapeutic potential of IL-31, a recombinant murine IL-31 molecule was fused to IgG via a linker region (IL-31-L-IgG). This IL-31-L-IgG therapy demonstrates antitumor therapeutic activity in a murine breast carcinoma model. CONCLUSIONS: Our findings demonstrate that IL-31 induces antitumor immunity, highlighting its potential utility as a therapeutic immunomodulatory agent.

The Potential Role of Immune Alteration in the Cancer-COVID19 Equation-A Prospective Longitudinal Study.

Background: The risk of cancer patients to develop COVID19 infection is unclear. We aimed to prospectively study cancer patients and oncology healthcare workers for COVID19 serology. In IgG+ cases, immune profile was determined to portray the pattern of immune response to SARS-CoV2. Methods: Cancer patients on active treatment and healthcare workers were enrolled. During the study period (3/2020-6/2020), demographic data and blood were collected at three time points. Expression of IgG, IgM, and IgA were assessed. In SARS-CoV-2 IgG+ cases and matched negative cases, we performed mass cytometry time of flight (CyTOF) analysis on the basis of the expression of surface markers. Results: The study included 164 cancer patients on active intravenous treatment and 107 healthcare workers at the cancer center. No symptomatic cases were reported during the study period. Serology analysis revealed four IgG+ patients (2.4%) and two IgG+ healthcare workers (1.9%)-all were asymptomatic. CyTOF analysis demonstrated substantial reduction in myeloid cells in healthcare workers who were SARS-CoV-2 IgG+ compared to those who were SARS-CoV-2 IgG-, whereas in cancer patients, the reduction was relatively milder (≈50% reduction in SARS-CoV-2 IgG+ cancer patients compared with ≈90% reduction in SARS-CoV-2 IgG+ workers). Conclusion: Our results indicate a similar rate of asymptomatic COVID19 infection in cancer patients and healthcare workers in a longitudinal study throughout the pandemic time. Due to differential immune cell profiles of cancer patients who are treated with immunomodulatory agents, the host response to the SARS-COV2 may play a role in COVID19 course and representation. The immunological perspective of cancer treatments on the risk for COVID19 infection should be further explored.