T-Scan: A Genome-wide Method for the Systematic Discovery of T Cell Epitopes.

T cell recognition of specific antigens mediates protection from pathogens and controls neoplasias, but can also cause autoimmunity. Our knowledge of T cell antigens and their implications for human health is limited by the technical limitations of T cell profiling technologies. Here, we present T-Scan, a high-throughput platform for identification of antigens productively recognized by T cells. T-Scan uses lentiviral delivery of antigen libraries into cells for endogenous processing and presentation on major histocompatibility complex (MHC) molecules. Target cells functionally recognized by T cells are isolated using a reporter for granzyme B activity, and the antigens mediating recognition are identified by next-generation sequencing. We show T-Scan correctly identifies cognate antigens of T cell receptors (TCRs) from viral and human genome-wide libraries. We apply T-Scan to discover new viral antigens, perform high-resolution mapping of TCR specificity, and characterize the reactivity of a tumor-derived TCR. T-Scan is a powerful approach for studying T cell responses.

Niclosamide-induced Wnt signaling inhibition in colorectal cancer is mediated by autophagy.

The Wnt signaling pathway, known for regulating genes critical to normal embryonic development and tissue homeostasis, is dysregulated in many types of cancer. Previously, we identified that the anthelmintic drug niclosamide inhibited Wnt signaling by promoting internalization of Wnt receptor Frizzled 1 and degradation of Wnt signaling pathway proteins, Dishevelled 2 and ß-catenin, contributing to suppression of colorectal cancer growth in vitro and in vivo Here, we provide evidence that niclosamide-mediated inhibition of Wnt signaling is mediated through autophagosomes induced by niclosamide. Specifically, niclosamide promotes the co-localization of Frizzled 1 or ß-catenin with LC3, an autophagosome marker. Niclosamide inhibition of Wnt signaling is attenuated in autophagosome-deficient ATG5-/- MEF cells or cells expressing shRNA targeting Beclin1, a critical constituent of autophagosome. Treatment with the autophagosome inhibitor 3MA blocks niclosamide-mediated Frizzled 1 degradation. The sensitivity of colorectal cancer cells to growth inhibition by niclosamide is correlated with autophagosome formation induced by niclosamide. Niclosamide inhibits mTORC1 and ULK1 activities and induces LC3B expression in niclosamide-sensitive cell lines, but not in the niclosamide-resistant cell lines tested. Interestingly, niclosamide is a less effective inhibitor of Wnt-responsive genes (ß-catenin, c-Myc, and Survivin) in the niclosamide-resistant cells than in the niclosamide-sensitive cells, suggesting that deficient autophagy induction by niclosamide compromises the effect of niclosamide on Wnt signaling. Our findings provide a mechanistic understanding of the role of autophagosomes in the inhibition of Wnt signaling by niclosamide and may provide biomarkers to assist selection of patients whose tumors are likely to respond to niclosamide.

Immune correlates of clinical benefit in a phase I study of hyperthermia with adoptive T cell immunotherapy in patients with solid tumors.

Purpose: To characterize the T cell receptor (TCR) repertoire, serum cytokine levels, peripheral blood T lymphocyte populations, safety, and clinical efficacy of hyperthermia (HT) combined with autologous adoptive cell therapy (ACT) and either salvage chemotherapy (CT) or anti-PD-1 antibody in patients with previously treated advanced solid tumors.Materials and methods: Thirty-three (33) patients with ovarian, pancreatic, gastric, colorectal, cervical, or endometrial cancer were recruited into the following therapeutic groups: HT + ACT (n = 10), HT + ACT + anti-PD-1 inhibitor (pembrolizumab) (n = 11) and HT + ACT + CT (n = 12). Peripheral blood was collected to analyze TCR repertoire, measurements of cytokines levels and lymphocyte sub-populations before and after treatment.Results: The objective response rate (ORR) was 30% (10/33), including three complete responses (CR) (9.1%) and seven partial responses (PR) (21.2%) and a disease control rate (DCR = CR + PR + SD) of 66.7% (22 of 33). The most common adverse reactions, blistering, subcutaneous fat induration, local heat-related pain, vomiting and sinus tachycardia, were observed in association with HT. IL-2, IL-4, TNF-α, and IFN-γ levels in peripheral blood were significantly increased among the clinical responders (p < 0.05) while IL-6 and IL-10 were elevated among those with progressive disease (p < 0.05). Peripheral blood CD8+/CD28+ T cells increased (p = 0.002), while the CD4+/CD25+/CD127+Treg cells decreased after therapy (p = 0.012). TCR diversity was substantially increased among the clinical responders.Conclusions: Combining HT with ACT plus either CT or anti-PD-1 antibody was safe, generated clinical responses in previously treated advanced cancers, and promoted TCR repertoire diversity and favorable changes in serum IL-2, IL-4, TNF-α, and IFN-γ levels in clinical responders.

Prospective randomized comparative study on rivaroxaban and LMWH for prophylaxis of post-apheresis thrombosis in adoptive T cell immunotherapy cancer patients.

Autologous adoptive T cell immunotherapy has been recognized as an effective treatment for cancer patients. The initial qualified lymphocytes is the core element determining the immunotherapeutic outcomes clinically. Cell separator based apheresis procedure is an optimal procedure to collect adequate mono-nucleated lymphocytes to generate efficient ex vivo T cell expansions; however, potential catheter-associated femoral vein thrombosis at post-apheresis might rise an additional deteriorated morbidity for cancer patients. The emerging prophylactic medications are required at such circumstances. Therefore this study was designed to compare the prophylactic effects of rivaroxaban versus low molecular weight heparin (LMWH) in patients who had exposed during the femoral vein catheterization for apheresis. 74 Patients were randomized 1:1:1 into three groups: subcutaneous injection of LMWH, Fraxiparine (n = 23) (0.4 ml, 3800 IU/day) for 2 days, oral rivaroxaban 10 mg/d (n = 26), and oral rivaroxaban 20 mg/d (n = 25) for consecutive 2 days. The primary endpoint was to compare the venous thromboembolism (VTE) occurrence cases in one month post catheterization. There were 4 cases confirmed VTE occurrence in LMWH group with contrast to 1 case in rivaroxaban 10 mg administration group. None was seen in rivaroxaban 20 mg group (P = 0.02 as the comparison with LMWH). Meantime there was no bleeding events occurrence afterwards. Oral rivaroxaban 20 mg/day was recommendable to be considered which superior to LMWH. Although these limited data and patient volume reached the statistical difference which was able to provide the evidence proofed to compare the potency of those two anticoagulants, it could be regarded as the preliminary data provide the clinical results for cancer patients who were placed in the condition of apheresis and subsequently undergone adoptive T cell immunotherapy.Trial registration ClinicalTrials.gov identifier, NCT03282643. Registered 16 February 2016, http://www.ClinicalTrials.gov/ NCT03282643.

Circulating CD8+CD28- suppressor T cells tied to poorer prognosis among metastatic breast cancer patients receiving adoptive T-cell therapy: A cohort study.

BACKGROUND AIMS: This study aimed to determine the prognostic value of circulating CD8+CD28- T lymphocytes among breast cancer patients treated with adoptive T-lymphocyte immunotherapy after chemotherapy. METHODS: Two hundred and thirty-two breast cancer patients underwent adoptive T-cell immunotherapy. Circulating CD8+CD28- proportion was measured by flow cytometry. Median proportion of CD8+CD28- was 24.2% and set as the categorical cutoff value for further analysis. The median survival was estimated by Kaplan-Meier curve, with difference detection and hazard ratio estimation by log-rank test and Cox hazard proportion regression model. RESULTS: With adoptive T-cell therapy, patients with higher CD8+CD28- levels experienced median progression-free and overall survival of 7.1 months and 26.9 months, respectively-significantly shorter than patients with lower levels (11.8 and 36.2 months). CD8+CD28- proportion >24.2% demonstrated a hazard ratio (HR) of 2.06 (95% confidence interval [CI] 1.31-3.12) for progression and an HR of 1.97 (95% CI 1.06-3.67) for death. Among patients who had received previous first-line chemotherapy, CD8+CD28- proportion >24.2% demonstrated an HR of 2.66 (95% CI 1.45-4.88) for progression. Among patients exposed to previous second-line or higher chemotherapy, CD8+CD28- proportion >24.2% demonstrated a 486% higher risk for death (HR = 5.86, 95% CI 1.77-19.39). A 1% increase in suppressive T cells was associated with a 5% increased risk of death. DISCUSSION: Elevated peripheral blood CD8+CD28- was associated with poorer prognosis for metastatic breast cancer, especially for higher risk of progression among patients with first-line chemotherapy and higher risk of death among patients with more than second-line chemotherapy.

Perhexiline promotes HER3 ablation through receptor internalization and inhibits tumor growth.

INTRODUCTION: Human epidermal growth factor receptor HER3 has been implicated in promoting the aggressiveness and metastatic potential of breast cancer. Upregulation of HER3 has been found to be a major mechanism underlying drug resistance to EGFR and HER2 tyrosine kinase inhibitors and to endocrine therapy in the treatment of breast cancer. Thus, agents that reduce HER3 expression at the plasma membrane may synergize with current therapies and offer a novel therapeutic strategy to improve treatment. METHODS: We devised an image-based screening platform using membrane localized HER3-YFP to identify small molecules that promote HER3 internalization and degradation. In vitro and in vivo tumor models were used to characterize the signaling effects of perhexiline, an anti-anginal drug, identified by the screening platform. RESULTS: We found perhexiline, an anti-anginal drug, selectively internalized HER3, decreased HER3 expression, and subsequently inhibited signaling downstream of HER3. Consistent with these results, perhexiline inhibited breast cancer cell proliferation in vitro and tumor growth in vivo. CONCLUSIONS: This is the first demonstration that HER3 can be targeted with small molecules by eliminating it from the cell membrane. The novel approach used here led to the discovery that perhexiline ablates HER3 expression, and offers an opportunity to identify HER3 ablation modulators as innovative therapeutics to improve survival in breast cancer patients.

Breast Cancer Challenges and Screening in China: Lessons From Current Registry Data and Population Screening Studies.

BACKGROUND: As one of its responses to the increasing global burden of breast cancer (BC), China has deployed a national registration and BC screening campaign. The present report describes these programs and the initial results of these national BC control strategies, highlighting the challenges to be considered. MATERIALS AND METHODS: The primary BC incidence and prevalence data were obtained from the Chinese National Central Cancer Registry. MapInfo software was used to map the geographic distribution and variation. The time trends were estimated by the annual percentage of change from 2003 to 2009. The description of the screening plans and preliminary results were provided by the Ministry of Health. RESULTS: Chinese cancer registries were primarily developed and activated in the East and Coastal regions of China, with only 12.5% of the registries located in West China. Geographic variation was noted, with the incidence of BC higher in North China than in South China and in urban areas compared with rural areas. Of great interest, these registries reported that the overall BC incidence has been increasing in China, with an earlier age of onset compared with Western countries and a peak incidence rate at age 50. In response to this increasing incidence and early age of onset, BC screening programs assessed 1.46 million women aged 35-59 years, using clinical breast examinations and ultrasound as primary screening tools between 2009 and 2011. The diagnostic rate for this screening program was only 48.0/10(5) with 440 cases of early stage BC. Early stage BC was detected in nearly 70% of screened patients. Subsequently, a second-generation screening program was conducted that included older women aged 35-64 years and an additional 6 million women were screened. CONCLUSION: The cancer registration system in China has been uneven, with a greater focus on East rather than West China. The data from these registries demonstrate regional variation, an increasing BC incidence, and an early age of onset. The 2009 to 2011 BC screening program targeting women aged 35-59 years had a low detection rate that resulted in a second-generation screening program that extended the cohort size and ages screened to 35-64 years. IMPLICATIONS FOR PRACTICE: Cancer registration has been active in China for decades; however, a national survey of registries has not been routinely reported. This study used MapInfo to describe the reported data and found asymmetric registration activities, geographic variations in breast cancer (BC) burdens, and an increasing incidence with a peak at age 50. The initial Chinese BC screening programs focused on a relatively young population of women aged 35-59 years and had a low detection rate, but 69.7% of patients had early stage BC. Older women were included in the second-generation screening programs, and an additional 6 million women were screened. Consideration of regional variations and age is necessary to optimize the efficiency and utility of BC screening in China, with the ultimate goal to reduce BC mortality.

Transformation of alkylating regimen of thiotepa into tepa determines the disease progression through GSTP1 gene polymorphism for metastatic breast cancer patients receiving thiotepa containing salvage chemotherapy.

BACKGROUND: The shifts to second-line chemotherapy for metastatic breast cancer (MBC) were widely required based on pharmaceutical molecular profiles to reach out precision medicine. The emerging precise treatment of cancer requires the implementation of clarified pharmacogenetic profiles which are capable of elucidating the predictive responses to cancer chemotherapy. Therefore we were interested in the analysis of the roles of single nucleotide polymorphism (SNP) of GSTP1 (glutathione S-transferase pi 1 gene) alleles to identify pharmacological links with predictors of clinical responses and toxicities. METHODS: 93 MBC patients receiving thiotepa plus docetaxel chemotherapy were enrolled in this study. Optimized CYP3A5, CYP2B6, and GSTP1 were predominantly selected as candidate genes and their three SNPs (CYP2B6 G516T, CYP3A5 A6986G, and GSTP1 A313G) were genotyped by matrix-assisted laser desorption ionization/time of flight (MALDI-TOF) mass spectrometry. Progression-free survival (PFS), disease control rate, and chemo-related toxicities were recorded. RESULTS: GSTP1 A313G (rs1695) was identified to be related with disease progression. In particular, patients harboring AG/GG genotype demonstrated a statistically longer PFS than those with AA. Multivariate analysis confirmed that AG/GG genotype was associated with both clinical responses and liver-localized metastatic lesions. No correlation was found between these three SNPs and chemotherapy-induced toxicity. CONCLUSIONS: These results suggest that the GSTP1 polymorphism is a novel prognostic marker for clinical response to thiotepa-containing chemotherapy regimens. Such evidence could provide insight into the role of pharmacogenetics to deprive of biases in shifting regimens solely by empirical choices.

Overcoming Xenoantigen Immunity to Enable Cellular Tracking and Gene Regulation with Immune-competent "NoGlow" Mice.

The ability to temporally regulate gene expression and track labeled cells makes animal models powerful biomedical tools. However, sudden expression of xenobiotic genes [e.g., GFP, luciferase (Luc), or rtTA3] can trigger inadvertent immunity that suppresses foreign protein expression or results in complete rejection of transplanted cells. Germline exposure to foreign antigens somewhat addresses these challenges; however, native fluorescence and bioluminescence abrogates the utility of reporter proteins and highly spatiotemporally restricted expression can lead to suboptimal xenoantigen tolerance. To overcome these unwanted immune responses and enable reliable cell tracking/gene regulation, we developed a novel mouse model that selectively expresses antigen-intact but nonfunctional forms of GFP and Luc, as well as rtTA3, after CRE-mediated recombination. Using tissue-specific CREs, we observed model and sex-based differences in immune tolerance to the encoded xenoantigens, illustrating the obstacles of tolerizing animals to foreign genes and validating the utility of these "NoGlow" mice to dissect mechanisms of central and peripheral tolerance. Critically, tissue unrestricted NoGlow mice possess no detectable background fluorescence or luminescence and exhibit limited adaptive immunity against encoded transgenic xenoantigens after vaccination. Moreover, we demonstrate that NoGlow mice allow tracking and tetracycline-inducible gene regulation of triple-transgenic cells expressing GFP/Luc/rtTA3, in contrast to transgene-negative immune-competent mice that eliminate these cells or prohibit metastatic seeding. Notably, this model enables de novo metastasis from orthotopically implanted, triple-transgenic tumor cells, despite high xenoantigen expression. Altogether, the NoGlow model provides a critical resource for in vivo studies across disciplines, including oncology, developmental biology, infectious disease, autoimmunity, and transplantation. SIGNIFICANCE: Multitolerant NoGlow mice enable tracking and gene manipulation of transplanted tumor cells without immune-mediated rejection, thus providing a platform to investigate novel mechanisms of adaptive immunity related to metastasis, immunotherapy, and tolerance.

Elevated level of peripheral CD8(+)CD28(-) T lymphocytes are an independent predictor of progression-free survival in patients with metastatic breast cancer during the course of chemotherapy.

PURPOSE: Suppression of cellular immunity resulting from tumorigenesis and/or therapy might promote cancer cells' growth, progression and invasion. Here, we explored whether T lymphocyte subtypes from peripheral blood of metastatic breast cancer (MBC) female patients could be used as alternative surrogate markers for cancer progress. Additionally, plasma levels of interleukin (IL)-2, IL-4, IL-6, IL-10, IFN-γ, and transforming growth factor-ß1 were quantitated from MBC and healthy volunteers. EXPERIMENTAL DESIGN: This study included 89 female MBC patients during the post-salvage chemotherapy follow-up and 50 age- and sex-matched healthy volunteers as control. The percentages of T lymphocyte subpopulations from peripheral blood and plasma levels of cytokines were measured. RESULTS: Both CD8(+)CD28(-) and CD4(+)CD25(+) were elevated in MBC patients compared to the control cohort (P < 0.05). In contrast, CD3(+) and CD8(+)CD28(+)cells were significantly lower in MBC patients (P < 0.0001, P = 0.045, respectively). MBC patients had elevated levels of immunosuppressive cytokines IL-6 and IL-10. Patients with elevated CD8(+)CD28(-) and CD4(+)CD25(+) cells showed increased levels of IL-6, and only patients with elevated CD8(+)CD28(-) had decreased interferon-γ. Univariate analysis indicated increased CD3(+)CD4(+) or CD8(+)CD28(+)correlated with prolonged progression-free survival (PFS), while elevated CD8(+)CD28(-)associated with shorten PFS. The percent of CD8(+)CD28(-) T lymphocytes is an independent predictor for PFS through multivariate analysis. CONCLUSIONS: This study suggests that progressive elevated levels of CD8(+)CD28(-) suppressor T lymphocytes represent a novel independent predictor of PFS during post-chemotherapy follow-up.

Non-genetic risk factors and predicting efficacy for docetaxel--drug-induced liver injury among metastatic breast cancer patients.

BACKGROUND AND AIM: Docetaxel has been chosen as one of the most popular anticancer drugs in the treatment of breast cancer for more than a decade. There is increasingly awareness for the occurrence of docetaxel and/or docetaxel-drug-induced liver injury (DILI), although the underlying mechanism of occurrence and its risk factors remain unclear. METHODS: We conducted a retrospective cohort study to identify non-genetic risk factors for docetaxel-DILI among 647 metastasis breast cancer patients treated with docetaxel-containing regimens. RESULTS: Sixty-seven (10.36%) patients were diagnosed as docetaxel-DILI. By logistic regression analysis, premenopausal status (odds ratio [OR][95% confidence interval {CI}] = 2.24 [1.30-3.87]), past hepatitis B virus (HBV) infections (OR [95% CI] = 4.23 [1.57-11.42]), liver metastasis (OR [95% CI] = 3.70 [2.16-6.34]). The predominant occurrence of DILI was seen in groups with docetaxel combination regimens. (OR [95% CI] = 2.66 [1.59-4.55]). The potential increasing occurrence of docetaxel-DILI was associated with multiple risk factors in an exposure-response manner (P < 0.001), and patients with more than three risk factors would be exposed to a 36.61-fold risk of DILI (95% CI = 10.18-131.62). Further analysis by the risk score and area under the receiver-operator characteristic curve (AUC) showed that those four factors contributed to an AUC of 0.7536 (95% CI = 0.70-0.81), with a predictive sensitivity of 74.63% and specificity of 65.17%. CONCLUSIONS: Docetaxel-DILI with a relatively higher incidence should be addressed among metastatic breast cancer patients. Four predominant risk factors, including premenopausal status, past HBV infection, liver metastasis, and docetaxel combination regimens, were potential predicators for DILI.

Combination of a novel heat shock protein 90-targeted photodynamic therapy with PD-1/PD-L1 blockade induces potent systemic antitumor efficacy and abscopal effect against breast cancers.

BACKGROUND: We previously demonstrated potent antitumor activity against human breast cancer xenografts using photodynamic therapy (PDT) targeting a novel tumor-specific photosensitizer (HS201), which binds heat shock protein 90 (HS201-PDT). However, induction of systemic antitumor immunity by HS201-PDT alone or by the combination strategy with immune checkpoint blockade has yet to be determined. METHODS: Using unilateral and bilateral implantation models of syngeneic breast tumors (E0771, MM3MG-HER2, and JC-HER3) in mice, we assessed whether HS201-PDT could induce local and systemic antitumor immunity. In an attempt to achieve a stronger abscopal effect for distant tumors, the combination strategy with anti-PD-L1 antibody was tested. Tumor-infiltrating leukocytes were analyzed by single cell RNA-sequencing and receptor-ligand interactome analysis to characterize in more detailed the mechanisms of action of the treatment and key signaling pathways involved. RESULTS: HS201-PDT demonstrated greater tumor control and survival in immune competent mice than in immunocompromised mice, suggesting the role of induced antitumor immunity; however, survival was modest and an abscopal effect on distant implanted tumor was weak. A combination of HS201-PDT with anti-PD-L1 antibody demonstrated the greatest antigen-specific immune response, tumor growth suppression, prolonged mouse survival time and abscopal effect. The most significant increase of intratumoral, activated CD8+T cells and decrease of exhausted CD8+T cells occurred following combination treatment compared with HS201-PDT monotherapy. Receptor-ligand interactome analysis showed marked enhancement of several pathways, such as CXCL, GALECTIN, GITRL, PECAM1 and NOTCH, associated with CD8+T cell activation in the combination group. Notably, the expression of the CXCR3 gene signature was the highest in the combination group, possibly explaining the enhanced tumor infiltration by T cells. CONCLUSIONS: The increased antitumor activity and upregulated CXCR3 gene signature induced by the combination of anti-PD-L1 antibody with HS201-PDT warrants the clinical testing of HS201-PDT combined with PD-1/PD-L1 blockade in patients with breast cancer, and the use of the CXCR3 gene signature as a biomarker.

A Non-Invasive Deep Photoablation Technique to Inhibit DCIS Progression and Induce Antitumor Immunity.

Ductal carcinoma in situ (DCIS) of the breast is often managed by lumpectomy and radiation or mastectomy, despite its indolent features. Effective non-invasive treatment strategies could reduce the morbidity of DCIS treatment. We have exploited the high heat shock protein 90 (HSP90) activity in premalignant and malignant breast disease to non-invasively detect and selectively ablate tumors using photodynamic therapy (PDT). PDT with the HSP90-targeting photosensitizer, HS201, can not only ablate invasive breast cancers (BCs) while sparing non-tumor tissue, but also induce antitumor immunity. We hypothesized that HS201-PDT would both non-invasively ablate DCIS and prevent progression to invasive BC. We tested in vitro selective uptake and photosensitivity of HS201 in DCIS cell lines compared to the non-selective parental verteporfin, and assessed in vivo antitumor efficacy in mammary fat pad and intraductal implantation models. Selective uptake of HS201 enabled treatment of intraductal lesions while minimizing toxicity to non-tumor tissue. The in vivo activity of HS201-PDT was also tested in female MMTV-neu mice prior to the development of spontaneous invasive BC. Mice aged 5 months were administered HS201, and their mammary glands were exposed to laser light. HS201-PDT delayed the emergence of invasive BC, significantly prolonged disease-free survival (DFS) (p = 0.0328) and tended to improve overall survival compared to the no-treatment control (p = 0.0872). Systemic administration of anti-PD-L1 was combined with HS201-PDT and was tested in a more aggressive spontaneous tumor model, HER2delta16 transgenic mice. A single PDT dose combined with anti-PD-L1 improved DFS compared to the no-treatment control, which was significantly improved with repetitive HS201-PDT given with anti-PD-L1 (p = 0.0319). In conclusion, a non-invasive, skin- and tissue-sparing PDT strategy in combination with anti-PD-L1 antibodies effectively prevented malignant progression of DCIS to invasive BC. This non-invasive treatment strategy of DCIS may be safe and effective, while providing an option to reduce the morbidity of current conventional treatment for patients with DCIS. Clinical testing of HS201 is currently underway.

Trastuzumab/pertuzumab combination therapy stimulates antitumor responses through complement-dependent cytotoxicity and phagocytosis.

Two HER2-specific mAbs, trastuzumab and pertuzumab (T+P), combined with chemotherapy comprise standard-of-care treatment for advanced HER2+ breast cancers (BC). While this antibody combination is highly effective, its synergistic mechanism-of-action (MOA) remains incompletely understood. Past studies have suggested that the synergy underlying this combination occurs through the different mechanisms elicited by these antibodies, with pertuzumab suppressing HER2 heterodimerization and trastuzumab inducing antitumor immunity. However, in vivo evidence for this synergy is lacking. In this study, we found that the therapeutic efficacy elicited by their combination occurs through their joint ability to activate the classical complement pathway, resulting in both complement-dependent cytotoxicity and complement-dependent cellular phagocytosis of HER2+ tumors. We also demonstrate that tumor C1q expression is positively associated with survival outcome in HER2+ BC patients and that complement regulators CD55 and CD59 were inversely correlated with outcome, suggesting the clinical importance of complement activity. Accordingly, inhibition of C1q in mice abolished the synergistic therapeutic activity of T+P therapy, whereas knockdown of CD55 and CD59 expression enhanced T+P efficacy. In summary, our study identifies classical complement activation as a significant antitumor MOA for T+P therapy that may be functionally enhanced to potentially augment clinical therapeutic efficacy.

Sensitizing immune unresponsive colorectal cancers to immune checkpoint inhibitors through MAVS overexpression.

BACKGROUND: The majority of colorectal carcinomas (CRCs) are insensitive to programmed death protein-1/programmed death-ligand 1 (anti-PD-1/PD-L1) immune checkpoint inhibitor (ICI) antibodies. While there are many causes for ICI insensitivity, recent studies suggest that suppression of innate immune gene expression in tumor cells could be a root cause of this insensitivity and an important factor in the evolution of tumor immunosuppression. METHODS: We first assessed the reduction of mitochondrial antiviral signaling gene (MAVS) and related RIG-I pathway gene expression in several patient RNA expression datasets. We then engineered MAVS expressing tumor cells and tested their ability to elicit innate and adaptive anti-tumor immunity using both in vitro and in vivo approaches, which we then confirmed using MAVS expressing viral vectors. Finally, we observed that MAVS stimulated PD-L1 expression in multiple cell types and then assessed the combination of PD-L1 ICI antibodies with MAVS tumor expression in vivo. RESULTS: MAVS was significantly downregulated in CRCs, but its re-expression could stimulate broad cellular interferon-related responses, in both murine and patient-derived CRCs. In vivo, local MAVS expression elicited significant anti-tumor responses in both immune-sensitive and insensitive CRC models, through the stimulation of an interferon responsive axis that provoked tumor antigen-specific adaptive immunity. Critically, we found that tumor-intrinsic MAVS expression triggered systemic adaptive immune responses that enabled abscopal CD8 +T cell cytotoxicity against distant CRCs. As MAVS also induced PD-L1 expression, we further found synergistic anti-tumor responses in combination with anti-PD-L1 ICIs. CONCLUSION: These data demonstrate that intratumoral MAVS expression results in local and systemic tumor antigen-specific T cell responses, which could be combined with PD-L1 ICI to permit effective anti-tumor immunotherapy in ICI resistant cancers.

Combination of ultrasound-based mechanical disruption of tumor with immune checkpoint blockade modifies tumor microenvironment and augments systemic antitumor immunity.

BACKGROUND: Despite multimodal adjuvant management with radiotherapy, chemotherapy and hormonal therapies, most surgically resected primary breast cancers relapse or metastasize. A potential solution to late and distant recurrence is to augment systemic antitumor immunity, in part by appropriately presenting tumor antigens, but also by modulating the immunosuppressive tumor microenvironment (TME). We previously validated this concept in models of murine carcinoma treated with a novel predominately microcavitating version of high-intensity focused ultrasound (HIFU), mechanical high-intensity focused ultrasound (M-HIFU). Here we elucidated the mechanisms of enhanced antitumor immunity by M-HIFU over conventional thermal high-intensity focused ultrasound (T-HIFU) and investigated the potential of the combinatorial strategy with an immune checkpoint inhibitor, anti-PD-L1 antibody. METHODS: The antitumor efficacy of treatments was investigated in syngeneic murine breast cancer models using triple-negative (E0771) or human ErbB-2 (HER2) expressing (MM3MG-HER2) tumors in C57BL/6 or BALB/c mice, respectively. Induction of systemic antitumor immunity by the treatments was tested using bilateral tumor implantation models. Flow cytometry, immunohistochemistry, and single-cell RNA sequencing were performed to elucidate detailed effects of HIFU treatments or combination treatment on TME, including the activation status of CD8 T cells and polarization of tumor-associated macrophages (TAMs). RESULTS: More potent systemic antitumor immunity and tumor growth suppression were induced by M-HIFU compared with T-HIFU. Molecular characterization of the TME after M-HIFU by single-cell RNA sequencing demonstrated repolarization of TAM to the immunostimulatory M1 subtype compared with TME post-T-HIFU. Concurrent anti-PD-L1 antibody administration or depletion of CD4+ T cells containing a population of regulatory T cells markedly increased T cell-mediated antitumor immunity and tumor growth suppression at distant, untreated tumor sites in M-HIFU treated mice compared with M-HIFU monotherapy. CD8 T and natural killer cells played major roles as effector cells in the combination treatment. CONCLUSIONS: Physical disruption of the TME by M-HIFU repolarizes TAM, enhances T-cell infiltration, and, when combined with anti-PD-L1 antibody, mediates superior systemic antitumor immune responses and distant tumor growth suppression. These findings suggest M-HIFU combined with anti-PD-L1 may be useful in reducing late recurrence or metastasis when applied to primary tumors.

Action for Increasing Diversity, Market Access, and Capacity in Oncology Registration Trials-Is Africa the Answer? Report From a Satellite Session of the Accelerating Anti-Cancer Agent Development and Validation Workshop.

Patients of African ancestry are not well-represented in cancer clinical trials despite bearing a disproportionate share of mortality both in United States and Africa. We describe key stakeholder perspectives and priorities related to bringing early-stage cancer clinical trials to Africa and outline essential action steps. Increasing Diversity, Market Access, and Capacity in Oncology Registration Trials-Is Africa the Answer? satellite session was organized at 2021 Accelerating Anti-Cancer Agent Development and Validation Workshop. Panelists included representatives of African Organization for Research and Training in Cancer, Uganda Cancer Institute, Uganda Women's Cancer Support Organization, BIO Ventures for Global Health, Bill & Melinda Gates Foundation, the US Food and Drug Administration, Nigeria's National Agency for Food and Drug Administration and Control, Bayer, and Genentech, with moderators from ASCO and American Cancer Society. Key discussion themes and resulting action steps were agreed upon by all participants. Panelists agreed that increasing diversity in cancer clinical trials by including African patients is key to ensuring novel drugs are safe and effective across populations. They underscored the importance of equity in clinical trial access for patients in Africa. Panelists discussed their values related to access and barriers to opening clinical trials in Africa and described innovative solutions from their work aimed at overcoming these obstacles. Multisectoral collaboration efforts that allow leveraging of limited resources and result in sustainable capacity building and mutually beneficial long-term partnerships were discussed as key to outlined action steps. The panel discussion resulted in valuable insights about key stakeholder values and priorities related to bringing early-stage clinical trials to Africa, as well as specific actions for each stakeholder group.

Serial assessment of circulating T lymphocyte phenotype and receptor repertoire during treatment of non-muscle invasive bladder cancer with adoptive T cell immunotherapy.

Recurrence and progression of non-muscle-invasive bladder cancer (NMIBC), frequent despite the availability of multiple treatment modalities, may be partly explained by the presence of immunosuppressive cell populations. We hypothesized that progression of disease could be prevented by the administration of an activated T cell immunotherapy (ACT) at time points when immunosuppressive populations increased in peripheral blood. In an N-of-1 study, a patient with multiple primary bladder high grade urothelial carcinomas, previously treated with standard local resection and chemotherapy but with evidence of progression, received ACT consisting of dendritic cells mixed with cytokine induced killer cells (DC/CIK), intravenously 18 times over a 6 year period at indicated time of observed increases in peripheral blood immunosuppressive CD8+/CD28- cells. Peripheral blood was analyzed for T cell phenotype by flow cytometry, T cell receptor (TCR) repertoire, and circulating tumor DNA (ctDNA) by next generation sequencing (NGS) at the time of each infusion. Cystoscopy and pelvic CT scans were performed at routine intervals to assess clinical status of disease. There has been no recurrence or metastasis of urothelial carcinoma. Peripheral blood cytotoxic T cells and unique TCR clones increased and suppressive T cell populations decreased after DC/CIK infusions evidenced by the two more proof-of concept cases. ctDNA analysis detected mutations in six genes (ARID1B, MYCN, CDH23, SETD2, NOTCH4 and FAT1) which appeared at different times, but all of them disappeared after the DC-CIK infusions. These data suggest that DC/CIK infusions may be associated with beneficial changes in T cell phenotype, TCR repertoire, decreases in circulating tumor DNA and sustained recurrence-free survival.

Changes in Peripheral Blood Regulatory T Cells and IL-6 and IL-10 Levels Predict Response of Pediatric Medulloblastoma and Germ Cell Tumors With Residual or Disseminated Disease to Craniospinal Irradiation.

PURPOSE: Radiation therapy (RT) modulates immune cells and cytokines, resulting in both clinically beneficial and detrimental effects. The changes in peripheral blood T lymphocyte subsets and cytokines during RT for pediatric brain tumors and the association of these changes with therapeutic outcomes have not been well described. METHODS AND MATERIALS: The study population consisted of children (n = 83, aged 3~18) with primary brain tumors (medulloblastoma, glioma, germ cell tumors (GCT), and central nervous system embryonal tumor-not otherwise specified), with or without residual or disseminated (R/D) diseases who were starting standard postoperative focal or craniospinal irradiation (CSI). Peripheral blood T lymphocyte subsets collected before and 4 weeks after RT were enumerated by flow cytometry. Plasma levels of interleukin (IL)-2, IL-4, IL-6, IL-10, tumor necrosis factor-α, interferon-γ, and IL-17A were measured by cytometric bead array. RESULTS: Patients with R/D lesions receiving CSI (n = 32) had a post-RT increase in the frequency of CD3+T and CD8+T cells, a decrease in CD4+T cells, and an increase in regulatory T cells (Tregs) and CD8+CD28- suppressor cells, which was more predominantly seen in these patients than in other groups. In the CSI group with such R/D lesions, consisting of patients with medulloblastoma and germ cell tumors, 19 experienced a complete response (CR) and 13 experienced a partial response (PR) on imaging at 4 weeks after RT. The post/pre-RT ratio of Tregs (P = .0493), IL-6 (P = .0111), and IL-10 (P = .0070) was lower in the CR group than in the PR group. Multivariate analysis revealed that the post/pre-RT ratios of Treg, IL-6, and IL-10 were independent predictors of CR (P < .0001, P = .018, P < .0001, respectively). The areas under the receiver operating curves and confidence intervals were 0.7652 (0.5831-0.8964), 0.7794 (0.5980-0.9067), and 0.7085 (0.5223-0.8552) for IL-6, IL-10, and Treg, respectively. The sensitivities of IL-6, IL-10, and Treg to predict radiotherapeutic responses were 100%, 92.3%, and 61.5%, and specificity was 52.6%, 57.9%, and 84.2%, respectively. CONCLUSIONS: CSI treatment to those with R/D lesions predominantly exerted an effect on antitumor immune response compared with both R/D lesion-free but exposed to focal or CSI RT and with R/D lesions and exposed to focal RT. Such CSI with R/D lesions group experiencing CR is more likely to have a decrease in immunoinhibitory molecules and cells than patients who only achieve PR. Measuring peripheral blood Treg, IL-6, and IL-10 levels could be valuable for predicting radiotherapeutic responses of pediatric brain tumors with R/D lesions to CSI for medulloblastoma and intracranial germ cell tumors.

Blood microbiota diversity determines response of advanced colorectal cancer to chemotherapy combined with adoptive T cell immunotherapy.

Human microbiota influence the response of malignancies to treatment with immune checkpoint blockade; however, their impact on other forms of immunotherapy is poorly understood. This study explored the effect of blood microbiota on clinical efficacy, represented by progression-free survival (PFS) and overall survival (OS), of combined chemotherapy and adoptive cellular therapy (ACT) in advanced colon cancer patients. Plasma was collected from colorectal cancer patients (CRC) treated with either chemotherapy alone (oxaliplatin and capecitabine) (XELOX CT alone group, n = 19), or ACT with a mixed dendritic cell/cytokine-induced killer cell product (DC-CIK) + XELOX (ICT group, n = 20). Circulating microbiota analysis was performed by PCR amplification and next-generation sequencing of variable regions V3~V4 of bacterial 16S rRNA genes. The association of the blood microbial diversity with clinical response to the therapy as measured by RECIST1.1 and OS was evaluated. The baseline Chao index of blood microbial diversity predicted prolonged PFS and OS of DC/CIK immunotherapy. More diverse blood microbiota that included Bifidobacterium, Lactobacillus, and Enterococcus were identified among responders to DC/CIK compared with non-responders. The plasma bacterial DNA copy number is inversely correlated with the CD3-/CD16+/CD56+ NK cells in circulation and decreased following DC-CIK; however, the Chao index of plasma microbiota significantly increased after administration of the DC-CIK product and this subsequent change was correlated with the number of CD3-/CD16+/CD56+ and CD8+/CD28+ cells infused. The diversity of the blood microbiome is a promising predictive marker for clinical responses to chemotherapy combined with DC-CIK. Cellular immunotherapy can affect the plasma microbiota's diversity in a manner favorable to clinical responses.