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Melanoma tumor cells secrete lysosomes which are taken up by dendritic cells

Cell numbers of multiple immune cell substes, and mainly dendritic cells, are decreased over time in melanoma tumors.

Tumor antigens are drained into sentinel lymph nodes independently of dendritic cell migration.

The recent success of checkpoint blockade therapies has established immunotherapy as one of the most promising treatments for melanoma. Nonetheless, a complete curative response following immunotherapy is observed only in a fraction of patients. To identify what factors limit the efficacy of immunotherapies, we established mouse models that cease to respond to immunotherapies once their tumors exceed a certain stage. Analysis of the immune systems of the organisms revealed that the numbers of tumor-infiltrating dendritic cells (TIDC) drastically decreased with time. Further, in contrast to the current paradigm, once melanoma was established, TIDC did not migrate into sentinel lymph nodes. Instead, they underwent local cell death due to excessive phagocytosis of lysosomes. Importantly, TIDC were required to license the cytotoxic activity of tumor CD8+ T cells, and in their absence, T cells did not lyse melanoma cells. Our results offer a paradigm shift regarding the role of TIDC and a framework to increase the efficacy of immunotherapies.Significance:This work redefines the role of monocyte-derived dendritic cells in melanoma and provides a novel strategy to increase the efficacy of T-cell–based immunotherapies in nonresponding individuals.

Proteins associated with myeloid dendritic cells positively correlate with improved survival of melanoma patients

Tumor-infiltrating dendritic cells promote, in a contact-dependant manner, secretion of lytic granules by CD8+ T cells.

Higher doses of immunmotherapy do not induce tumor regression when administrated to large melanoma lesions.

While Immunotherapy has revolutionized the treatment of several cancers such as lung cancer, melanoma, and other cancers, most colorectal cancer patients remain resistant. This resistance to immunotherapy may partially stem from the fact that colorectal cancer very commonly metastasizes to the liver. The liver is known to play an immunotolerant role in in other contexts such as organ transplantation, viral disease, and autoimmune disease. Recent studies reveal the mechanisms in which liver metastases restrict the efficacy of immunotherapy. This effect was shown to be reversable in colorectal cancer mice models, when colorectal liver metastases were irradiated. It is possible that targeting liver metastases with locoregional therapies such as ablation, resection or irradiation may reverse the immunosuppressive effect of liver microenvironment and potentiate immunotherapy systemically. During the past decade, several clinical trials are trying to extrapolate the results achieved in animal model to clinical trials by combining immunotherapy with locoregional therapy. In this scoping review, the current clinical and translational literature was surveyed, to determine whether there is evidence to support the validity of this concept in human patients. If indeed immunotherapy can be potentiated for MS- Stable colorectal cancer utilizing locoregional interventions, a wide array of innovative protocols can be utilized to help cancer patients who have no other available treatment options and thus revolutionize the treatment of cancer patients with liver metastases.

Favorable pathologic response(FPR) is a significant predictor for improved survival following Neoadjuvant therapy(NAT) in esophageal and gastroesophageal cancer(GEJ). Preoperative prediction of FPR could modify treatment plans. No reliable method for predicting FPR exists. We sought to identify preoperative predicting factors for FPR.Retrospective analysis of patients with esophageal and GEJ cancer who underwent esophagectomy following (NAT). Univariate and multivariate analysis was used to identify preoperative predicting factors for FPR. A comparison of Tumor Regression Grade(TRG) was used to assess treatment response on overall survival(OS).Out of 121 patients, 82(67.8%) had neoadjuvant chemoradiation. FPR was observed in 60(49.6%). Female sex, Radiation therapy(RT), squamous cell carcinoma(SCC), lack of signet ring feature, and FDG avidity posttreatment were associated with FPR on univariate analysis. RT and SCC were associated with FPR (OR=3.9 and 4.0, respectively) on multivariate analysis. OS was lower among patients who did not achieve FPR to NAT(P=0.027).FPR is a predictor of improved OS. SCC and radiation therapy-based protocol were identified as major prediction factors of FPR in patients with esophageal and GEJ cancers.

Introduction: Colorectal cancer liver metastasis (CRCLM) remains a lethal diagnosis with an overall 5-year survival rate of 5–10%. Two distinct histopathological growth patterns (HGPs) of CRCLM are known to have significantly differing rates of patients survival, and response to treatment. We set out to review the results of 275 patients who underwent liver resection for CRCLM at the McGill University Health Center (MUHC) and analyze their clinical outcome, mutational burden and pattern of cancer progression in light of their HGP’s, and to consider their potential effect on surgical decision making. Methods We performed a retrospective multivariate analysis on clinical data from patients with CRCLM (n = 275) who underwent liver resection at the McGill University Health Center (MUHC). All tumors were scored using international consensus guidelines by pathologists trained in HGP scoring. Results 109 patients (42.2%) were classified as desmoplastic and angiogenic whereas 149 patients (57.7%) were non-desmoplastic and vessel co-opting. The 5 year survival rates for angiogenic patients compared to vessel co-opting patients was 47.1% and 13% respectively (p

Colorectal cancer liver metastases (CRCLM) have two major histopathological growth patterns (HGPs) including angiogenic desmoplastic HGP (DHGP) and non-angiogenic replacement HGP (RHGP). The RHGP lesions obtain their blood supply through vessel co-option, where the cancer cells hijack the pre-existing blood vessels of the surrounding liver tissue. Consequently, anti-angiogenic therapies are less efficacious in CRCLM patients with RHGP lesions. Recently, we identified a positive correlation between the expression of Angiopoietin1 (Ang1) and the development of vessel co-opted CRCLM lesions in vivo. However, the mechanisms underlying Ang1 upregulation in vessel co-opting CRCLM lesions are unclear. Herein, we demonstrated that transforming growth factor β1 (TGFβ1) modulates the expression of Ang1 in hepatocytes in vitro. Significantly, pharmaceutical inhibition of integrin alpha-5/beta-1 (ITGα5β1) through ATN-161 impaired TGFβ1-dependent Ang1 expression in vitro and in vivo. Moreover, blocking ITGα5β1 attenuated the formation of vessel co-opting lesions. Furthermore, treatment with ATN-161 significantly improved survival in tumour-bearing mice. Taken together, our results suggest the molecular mechanism of Ang1 upregulation in vessel co-opting CRCLM and targeting this pathway may serve as promising therapeutic strategy to overcome the development of vessel co-option in CRCLM.

31 Background: Colorectal cancer (CRC) remains a lethal diagnosis with an overall 5-year survival rate of 5-10% for patients with unresectable metastatic disease. The advent of next generation sequencing allows tailored systemic therapy to specific mutations with the goal of improving patient survival. McGill University Health Center instituted next generation sequencing in 2019. Our study aims to evaluate survival outcomes in patients who underwent NGS testing. Methods: A retrospective collection of data on all patients with CRC who were presented at both lower gastroenterology and hepatobiliary tumor boards from January 2019 through July 2022 ( n= 498). Survival and was compared between patients who were found to have genetic alterations identified using the Illumina Miseo platform. Statistical Analysis was performed with GraphPad Prism. Results: A total of 321 (64%) patients had NGS performed on either their primary tumor or a metastasis. A total of 229 (71%) CRC patients had genetic alterations identified on NGS. The most commonly mutated genes were KRAS (41%), APC (17%), PIK3CA (16%) and BRAF (8%). There was no significant difference in median overall survival between patients who had an identified genetic alteration and patients who did not (p = 0.8). Patients with metastatic disease and synchronous presentation had higher rates of genetic alterations (69% and 70%, respectively). Conclusions: This study provides real world data for a single institution initiating Next generation sequencing in colorectal cancer patients. Next Generation testing is an advantageous tool which can help stratify patients into tailored treatment regiments which will lead to improved patient outcomes.

The recent success of checkpoint blockade therapies has established immunotherapy as one of the most promising treatments for melanoma. Nonetheless, a complete curative response following immunotherapy is observed only in a fraction of patients. To identify what factors limit the efficacy of immunotherapies, we established mouse models that cease to respond to immunotherapies once their tumors exceed a certain stage. Analysis of the immune systems of the organisms revealed that the numbers of tumor-infiltrating dendritic cells (TIDC) drastically decreased with time. Further, in contrast to the current paradigm, once melanoma was established, TIDC did not migrate into sentinel lymph nodes. Instead, they underwent local cell death due to excessive phagocytosis of lysosomes. Importantly, TIDC were required to license the cytotoxic activity of tumor CD8+ T cells, and in their absence, T cells did not lyse melanoma cells. Our results offer a paradigm shift regarding the role of TIDC and a framework to increase the efficacy of immunotherapies. Significance: This work redefines the role of monocyte-derived dendritic cells in melanoma and provides a novel strategy to increase the efficacy of T-cell–based immunotherapies in nonresponding individuals.

(1) Background: We aimed to explore the association between neoadjuvant treatment, tumor-infiltrating immune lymphocyte (TIL), and tumor-associated macrophage (TAM) and survival in patients with esophageal adenocarcinoma. (2) Methods: Patients who underwent esophagectomy were divided into three groups according to their treatment modality and tumor regression grade (TRG): (i) surgery-only group (SG), (ii) good responders (GR) group (TRG 0–1), and (iii) bad responders (BR) group (TRG 2–3). We then carried out statistical correlations of the immunofluorescence analysis of the immune infiltrate in the esophageal surgical specimens with several clinical and pathological parameters. In addition, we analyzed The Cancer Genomic Atlas (TCGA) dataset for differences in TILs, TAMs, and protein expression in immune pathways. (3) Results: Forty-three patients (SG—15, GR—13, and BR—13) were evaluated. The highest enrichment of CD3+ (p < 0.001), CD8+ (p = 0.001) and CD4+ (p = 0.009) was observed in the stroma of GR patients. On multivariate analysis, only CD8+ T cell and signet-ring features were independent prognostic factors for overall survival. In TCGA analysis, we identified overexpression of TAM and colony-stimulating factor 1 receptor (CSF-1R). (4) Conclusions: High enrichment of lymphocyte subpopulations in the microenvironment of esophageal adenocarcinoma is associated with a favorable response to neoadjuvant treatment and an improved patient outcome.

BACKGROUND Esophageal cancer represents a global challenge. Despite significant evolution of treatment protocols in the past decade, recurrence rates are still high and survival rates are poor. Current treatment paradigm for localized gastroesophageal junction (GEJ) carcinoma remains to be further elucidated as for the role of neoadjuvant chemoradiation versus perioperative chemotherapy. AIM To identify biomarkers for response to chemoradiation in esophageal and gastroesophageal cancer, we performed an in-depth proteomic analysis of esophageal and gastroesophageal tumors, to describe differences in pathway activation between patients with favorable and poor prognosis following neoadjuvant chemoradiation. METHODS Patients with locally advanced esophageal and gastroesophageal cancer following neoadjuvant chemoradiation were included in the cohort. The study cohort was dichotomized into two groups of patients, named "favorable prognosis" and "poor prognosis" according to the postoperative disease-free interval. We performed a mass spectrometry analysis of proteins extracted from the malignant regions of surgical specimens and analyzed data from electronic medical records. Clinical data was correlated with differences in protein expression between patient with a favorable and poor prognosis using validated gene expression pathways. RESULTS The study included 35 patients with adenocarcinoma. All patients in this cohort had esophageal adenocarcinoma. Patients median age was 62 years. Twenty-five (71.3%) patients underwent neoadjuvant chemoradiation, and 28.7% underwent neoadjuvant chemotherapy only. A proteomic analysis of our cohort identified 2885 proteins. Enrichment levels of 98 of these proteins differed significantly between favorable and poor prognosis cohorts in patients who underwent neoadjuvant chemoradiation (p

Background Sentinel lymph node biopsy (SLNB) is routinely performed during surgery for malignant melanoma, using double mapping. Still, in some cases, a sentinel lymph node identified pre-operatively by lymphoscintigraphy is not identified during surgery. We hypothesized that disease specific survival would not be significantly impacted by intra-operative lymph node mapping (IOLM) failure. Methods The patient population study included 1300 malignant melanomas operated on by a single surgical oncologist (H.G.) after sentinel lymph node scintigraphy. Patients were included in the analysis if intra-operative lymph node (IOLM) mapping failed. Results Among 1300 patients who underwent surgery for malignant melanoma during the study period and after median follow up of >10 years, 33/36 lymphatic drainage basins with failed sentinel node identification were free of disease. Disease specific survival for the entire group of 33 patients with IOLM failure was 91.0%, which is comparable to previously published disease specific survival for all melanoma patients. Conclusion We conclude that failure to identify a pre-operatively marked sentinel lymph node by an experienced melanoma surgeon has, generally, no impact on disease specific survival, as demonstrated in this review of a series of surgical melanoma patients.

Breast cancer subtypes have not shown significant response to current immunomodulatory therapies. Although most subtypes are treatable, triple negative breast cancer (TNBC), an aggressive highly metastatic cancer, comprising 10–20% of breast cancers, remains an unmet medical need. New strategies are needed in order to overcome flaws in the responsiveness to current TNBC therapies. Our aims were: first, to determine the efficacy of a novel immunomodulatory peptide, C24D, on TNBC and second, to elucidate the molecular mechanism by which C24D induces immune-modulating tumor killing. Using mass spectrometry analysis, we identified CD45 as the C24D binding receptor. In vitro and in vivo TNBC models were used to assess the efficacy of C24D in reversing TNBC-induced immunosuppression and in triggering immune-modulated tumor cell killing. The CD45 signal transduction pathway was evaluated by western blot and FACS analyses. We revealed that addition of PBMCs from healthy female donors to TNBC cells results in a cascade of suppressive CD45 intracellular signals. On binding to CD45’s extra-cellular domain on TNBC-suppressed leukocytes, the C24D peptide re-activates the Src family of tyrosine kinases, resulting in specific tumor immune response. In vitro, immune reactivation by C24D results in an increase of CD69+ T and CD69+ NK cells, triggering specific killing of TNBC cells. In vivo, C24D induced CD8+ and activated CD56+ tumor infiltrated cells, resulting in tumor apoptosis. Our results should renew interest in molecules targeting CD45, such as the C24D peptide, as a novel strategy for TNBC immunotherapy.

Despite the remarkable success of immunotherapy in cancer, most patients will develop resistant tumors. While the main conceptual paradigm suggests that relapsed clones emerge through a process of clonal selection and immunoediting, currently little evidence directly demonstrates this process in epithelial cancers.To study this process, we established several mouse models in which tumors drastically regress following immunotherapy, yet resistant tumors relapse within a few weeks of treatment cessation. Whole exome analyses indicated that relapsed tumors share hundreds of neo-antigens with the primary tumors and are comparably killed by reactive T cells. Examination of tumor cells that survive immunotherapies revealed that they structure a transient cell-in-cell formation, which is impenetrable to immune-derived cytotoxic compounds and to chemotherapies. This formation is mediated predominantly by a cell-membrane protein on activated T cells, which subsequently induces epidermal growth factor receptors and STAT3 phosphorylation in tumors cells. In contrast to previous reports on cell-in-cell formations, here both cells remain alive and can disseminate into single tumor cells once T cells are no longer present.Overall, this work highlights a powerful resistance mechanism which enable tumor cells to survive immune pressure and provides a new theoretical framework for combining chemotherapies and immunotherapies.

Introduction:The project was provided under the auspice and support of the Israel Agency for International Development Cooperation (MASHAV) at the Ministry of Foreign Affairs (MFA). Togo, one of the smallest and least developed countries in West Africa, has a population of ~7.9 million. About 65% of its population lives in rural areas. Due to the lack of medical resources, Togo suffers from health problems including those related to trauma and mass events. In May 2017, a trauma and disaster team came to Togo to train the medical team in the new trauma unit, donated and built by the MFA. The unit was built in the Atakpame Regional Hospital (ARH), located 160km north of the capital, Lomé. ARH serves one million inhabitants, mostly from rural areas.Methods:The training included lectures, simulations, drills, case studies, bedside teaching, and operation of medical technologies.Results:Following the training, it was recommended to continue the program and to move forward with advanced training. Following the team’s recommendations, MASHAV decided to expand the program and to provide a multilateral project to Togo and ten other West African countries within five months after the first training ended. Twenty participants (mostly senior doctors) were chosen from ten Western African countries and brought to Lomé. The participants joined a two-day Trauma and Disaster Preparedness seminar. Following the seminar, they were moved to Atakpame to join the local team and the facilitators, to visit the trauma unit, and to learn about it as a model for trauma care that can be modified to the capabilities of the local facility.Discussion:Lessons learned and recommendations from those two projects were brought to the MFA that will try to develop more training and cooperation models to help and establish better trauma care and disaster response, supported by the Israeli team.

61 Background: Neoadjuvant chemoradiotherapy (NCRT) followed by surgery represents a key therapeutic strategy for locally advanced esophageal cancer (LAEC). Former studies addressed the clinicopathological patterns of patients who demonstrated good response to NCRT compared with inferior response. Nevertheless, there is paucity of data regarding potentially involved cellular pathways that account for tumor response to NCRT. We performed a comprehensive proteomic analysis to identify the key differences in protein function and pathway activation between patients with a poor response and those with a favourable response to treatment. Methods: Patients diagnosed with LAEC who were treated with NCRT and operated at our institution were included in the study. Patients were defined as good responders (GR) upon the tumor regression grade (TRG) in the pathological specimen: GR defined as TRG 0/1 and no evidence of recurrence at 1-year post surgery. Bad responders (BR) were defined as TRG 2/3 and recurrence < 1year. Tumor was isolated from the surgical specimen and proteins were extracted and processed for mass spectrometry-based analysis. Clinical data of demographics, response to treatment, and survival was retrieved from electronic medical records. Difference in protein expression between GR and BR were analysed using validated gene expression pathways tools and correlated to clinical data. Results: Forty-four patients were included in the cohort. Mean age was 66.7 years, male predominance (33/44). Thirty-five patients had adenocarcinoma – 17 GR and 18 BR. Nine patients had squamous cell carcinoma – 6 GR and 3 BR. Protein expression patterns significantly differed between GR and BR regardless of histology, mainly in cellular pathways account for nucleic acid metabolism (p < 10-9), whereas BR had overexpression of these genes. Conclusions: Our study indicate that lack of response to NCRT may derive from overexpression of unique cellular pathways. Former studies imply these cellular pathways may play a role in resistance to cisplatin. Larger transcriptomic studies are warranted for future analysis to extend these observations.