Dual targeting of TIGIT and PD-1 with a novel small molecule for cancer immunotherapy.

Immune checkpoint inhibitors have unveiled promising clinical prospects in cancer treatment. Nonetheless, their effectiveness remains restricted, marked by consistently low response rates and affecting only a subset of patients. The co-blockade of TIGIT with PD-1 has exhibited substantial anti-tumor effects. Notably, there is a dearth of reports on small-molecule inhibitors concurrently targeting both TIGIT and PD-1. In this study, we employed Microscale Thermophoresis (MST) to screen our laboratory's existing repository of small molecules. Our findings illuminated Gln(TrT) 's affinity for both TIGIT and PD-1, affirming its potential to effectively inhibit TIGIT/PVR and PD-1/PD-L1 pathways. In vitro co-culture experiments substantiated Gln(TrT)'s proficiency in restoring Jurkat T-cell functionality by blocking both TIGIT/PVR and PD-1/PD-L1 interactions. In the MC38 murine tumor model, Gln(TrT) emerges as a pivotal modulator, promoting the intratumoral infiltration and functional competence of CD8+ T cells. Furthermore, whether used as a monotherapy or in conjunction with radiotherapy, Gln(TrT) substantially impedes MC38 tumor progression, significantly extending the survival of murine subjects.

Development of LAG-3/FGL1 blocking peptide and combination with radiotherapy for cancer immunotherapy.

Aside from antibodies, peptides show great potential as immune checkpoint inhibitors (ICIs) due to several advantages, such as better tumor penetration and lower cost. Lymphocyte-activation gene 3 (LAG-3) is an immune checkpoint which can induce T cell dysfunction through interaction with its soluble ligand fibrinogen like protein-1 (FGL1). Here, we found that LAG-3 expression was higher than programmed cell death protein 1 (PD-1) in multiple human cancers by TCGA databases, and successfully identified a LAG-3 binding peptide LFP-6 by phage display bio-panning, which specifically blocks the interaction of LAG-3/FGL1 but not LAG-3/MHC-II. Subsequently, d-amino acids were introduced to substitute the N- and C-terminus of LFP-6 to obtain the proteolysis-resistant peptide LFP-D1, which restores T cell function in vitro and inhibits tumor growth in vivo. Further, a bispecific peptide LFOP targeting both PD-1/PD-L1 and LAG-3/FGL1 was designed by conjugating LFP-D1 with PD-1/PD-L1 blocking peptide OPBP-1(8-12), which activates T cell with enhanced proliferation and IFN-γ production. More importantly, LFOP combined with radiotherapy significantly improve the T cell infiltration in tumor and elevate systemic antitumor immune response. In conclusion, we developed a novel peptide blocking LAG-3/FGL1 which can restore T cell function, and the bispecific peptide synergizes with radiotherapy to further enhance the antitumor immune response.

An integrated framework for prognosis prediction and drug response modeling in colorectal liver metastasis drug discovery.

BACKGROUND: Colorectal cancer (CRC) is the third most prevalent cancer globally, and liver metastasis (CRLM) is the primary cause of death. Hence, it is essential to discover novel prognostic biomarkers and therapeutic drugs for CRLM. METHODS: This study developed two liver metastasis-associated prognostic signatures based on differentially expressed genes (DEGs) in CRLM. Additionally, we employed an interpretable deep learning model utilizing drug sensitivity databases to identify potential therapeutic drugs for high-risk CRLM patients. Subsequently, in vitro and in vivo experiments were performed to verify the efficacy of these compounds. RESULTS: These two prognostic models exhibited superior performance compared to previously reported ones. Obatoclax, a BCL-2 inhibitor, showed significant differential responses between high and low risk groups classified by prognostic models, and demonstrated remarkable effectiveness in both Transwell assay and CT26 colorectal liver metastasis mouse model. CONCLUSIONS: This study highlights the significance of developing specialized prognostication approaches and investigating effective therapeutic drugs for patients with CRLM. The application of a deep learning drug response model provides a new drug discovery strategy for translational medicine in precision oncology.

Discovery of a novel small molecule as CD47/SIRPα and PD-1/PD-L1 dual inhibitor for cancer immunotherapy.

BACKGROUND: Targeting the tumor microenvironment (TME) has emerged as a promising strategy in cancer treatment, particularly through the utilization of immune checkpoint blockade (ICB) agents such as PD-1/PD-L1 inhibitors. Despite partial success, the presence of tumor-associated macrophages (TAMs) contributes to an immunosuppressive TME that fosters tumor progression, and diminishes the therapeutic efficacy of ICB. Blockade of the CD47/SIRPα pathway has proven to be an effective intervention, that restores macrophage phagocytosis and yields substantial antitumor effects, especially when combined with PD-1/PD-L1 blockade. Therefore, the identification of small molecules capable of simultaneously blocking CD47/SIRPα and PD-1/PD-L1 interactions has remained imperative. METHODS: SMC18, a small molecule with the capacity of targeting both SIRPα and PD-L1 was obtained using MST. The efficiency of SMC18 in interrupting CD47/SIRPα and PD-1/PD-L1 interactions was tested by the blocking assay. The function of SMC18 in enhancing the activity of macrophages and T cells was tested using phagocytosis assay and co-culture assay. The antitumor effects and mechanisms of SMC18 were investigated in the MC38-bearing mouse model. RESULTS: SMC18, a small molecule that dual-targets both SIRPα and PD-L1 protein, was identified. SMC18 effectively blocked CD47/SIRPα interaction, thereby restoring macrophage phagocytosis, and disrupted PD-1/PD-L1 interactions, thus activating Jurkat cells, as evidenced by increased secretion of IL-2. SMC18 demonstrated substantial inhibition of MC38 tumor growths through promoting the infiltration of CD8+ T and M1-type macrophages into tumor sites, while also priming the function of CD8+ T cells and macrophages. Moreover, SMC18 in combination with radiotherapy (RT) further improved the therapeutic efficacy. CONCLUSION: Our findings suggested that the small molecule compound SMC18, which dual-targets the CD47/SIRPα and PD-1/PD-L1 pathways, could be a candidate for promoting macrophage- and T-cell-mediated phagocytosis and immune responses in cancer immunotherapy.

Hemin blocks TIGIT/PVR interaction and induces ferroptosis to elicit synergistic effects of cancer immunotherapy.

The immune checkpoint TIGIT/PVR blockade exhibits significant antitumor effects through activation of NK and CD8+ T cell-mediated cytotoxicity. Immune checkpoint blockade (ICB) could induce tumor ferroptosis through IFN-γ released by immune cells, indicating the synergetic effects of ICB with ferroptosis in inhibiting tumor growth. However, the development of TIGIT/PVR inhibitors with ferroptosis-inducing effects has not been explored yet. In this study, the small molecule Hemin that could bind with TIGIT to block TIGIT/PVR interaction was screened by virtual molecular docking and cell-based blocking assay. Hemin could effectively restore the IL-2 secretion from Jurkat-hTIGIT cells. Hemin reinvigorated the function of CD8+ T cells to secrete IFN-γ and the elevated IFN-γ could synergize with Hemin to induce ferroptosis in tumor cells. Hemin inhibited tumor growth by boosting CD8+ T cell immune response and inducing ferroptosis in CT26 tumor model. More importantly, Hemin in combination with PD-1/PD-L1 blockade exhibited more effective antitumor efficacy in anti-PD-1 resistant B16 tumor model. In summary, our finding indicated that Hemin blocked TIGIT/PVR interaction and induced tumor cell ferroptosis, which provided a new therapeutic strategy to combine immunotherapy and ferroptosis for cancer treatment.

Fish oil-based microemulsion can efficiently deliver oral peptide blocking PD-1/PD-L1 and simultaneously induce ferroptosis for cancer immunotherapy.

Peptide immune checkpoint inhibitors in cancer immunotherapy have attracted great attention recently, but oral delivery of these peptides remains a huge challenge due to the harsh gastrointestinal environment, large molecular size, high hydrophilic, and poor transmembrane permeability. Here, for the first time, a fish oil-based microemulsion was developed for oral delivery of programmed death-1/programmed cell death-ligand 1 (PD-1/PD-L1) blocking model peptide, OPBP-1. The delivery system was characterized, in vitro and in vivo studies were conducted to evaluate its overall implication. As a result, this nutraceutical microemulsion was easily formed without the need of co-surfactants, and it appeared light yellow, transparent, good flowability with a particle size of 152 ± 0.73 nm, with a sustained drug release manner of 56.45 ± 0.36% over 24 h and a great stability within the harsh intestinal environment. It enhanced intestinal drug uptake and transportation over human intestinal epithelial Caco-2 cells, and drastically elevated the oral peptide bioavailability of 4.1-fold higher than that of OPBP-1 solution. Meanwhile, the mechanism of these dietary droplets permeated over the intestinal enterocytic membrane was found via clathrin and caveolae-mediated endocytic pathways. From the in vivo studies, the microemulsion facilitated the infiltration of CD8+ T lymphocytes in tumors, with increased interferon-γ (IFN-γ) secretion. Thus, it manifested a promising immune anti-tumor effect and significantly inhibited the growth of murine colonic carcinoma (CT26). Furthermore, it was found that the fish oil could induce ferroptosis in tumor cells and exhibited synergistic effect with OPBP-1 for cancer immunotherapy. In conclusion, this fish oil-based formulation demonstrated great potential for oral delivery of peptides with its natural property in reactive oxygen species (ROS)-related ferroptosis of tumor cells, which provides a great platform for functional green oral delivery system in cancer immunotherapy.

Identification and optimization of peptide inhibitors to block VISTA/PSGL-1 interaction for cancer immunotherapy.

Developing new therapeutic agents for cancer immunotherapy is highly demanding due to the low response ratio of PD-1/PD-L1 blockade in cancer patients. Here, we discovered that the novel immune checkpoint VISTA is highly expressed on a variety of tumor-infiltrating immune cells, especially myeloid derived suppressor cells (MDSCs) and CD8+ T cells. Then, peptide C1 with binding affinity to VISTA was developed by phage displayed bio-panning technique, and its mutant peptide VS3 was obtained by molecular docking based mutation. Peptide VS3 could bind VISTA with high affinity and block its interaction with ligand PSGL-1 under acidic condition, and elicit anti-tumor activity in vivo. The peptide DVS3-Pal was further designed by d-amino acid substitution and fatty acid modification, which exhibited strong proteolytic stability and significant anti-tumor activity through enhancing CD8+ T cell function and decreasing MDSCs infiltration. This is the first study to develop peptides to block VISTA/PSGL-1 interaction, which could act as promising candidates for cancer immunotherapy.

Development of a novel peptide targeting GPR81 to suppress adipocyte-mediated tumor progression.

GPR81, initially discovered in adipocytes, has been found to suppress lipolysis when activated. However, the current small molecules that target GPR81 carry the risk of off-target effects, and their impact on tumor progression remains uncertain. Here, we utilized phage display technology to screen a GPR81-targeting peptide named 7w-2 and proceeded to demonstrate its bioactivity. Although 7w-2 did not affect the proliferation of tumor cells, it effectively reduced adipocyte catabolism in vitro, consequently restraining the proliferation of co-cultured tumor cells. Furthermore, our findings revealed that 7w-2 could inhibit lipolysis in vivo, leading to a significant impediment in tumor growth and metastasis in the 4T1 murine tumor model. Additionally, 7w-2 exhibited the ability to significantly elevate the proportion and functionality of CD8+ T cells. Our study introduces 7w-2 as the first peptide targeting GPR81, shedding light on its potential role in adipocytes in suppressing tumor progression.

Discovery of a novel dual-targeting D-peptide to block CD24/Siglec-10 and PD-1/PD-L1 interaction and synergize with radiotherapy for cancer immunotherapy.

BACKGROUND: Aside from immune checkpoint inhibitors targeting programmed cell death protein 1 (PD-1) and programmed death ligand 1 (PD-L1), intervention of CD47/Sirpα mediated 'don't eat me' signal between macrophage and tumor cell is considered as a promising therapeutic approach for cancer immunotherapy. Compared with CD47, the novel immune checkpoint CD24/Siglec-10 can also deliver 'don't eat me' signal and CD24 shows much lower expression level in normal tissue which might avoid unwanted side effects. METHODS: Cell-based phage display biopanning and D-amino acid modification strategy were used to identify the CD24/Siglec-10 blocking peptide. Cell-based blocking assay and microscale thermophoresis assay were used to validate the blocking and binding activities of the peptide. Phagocytosis and co-culture assays were used to explore the in vitro function of the peptide. Flow cytometry was performed to assess the immune microenvironment after the peptide treatment in vivo. RESULTS: A CD24/Siglec-10 blocking peptide (CSBP) with hydrolysis-resistant property was identified. Surprisingly, we found that CSBP could not only block the interaction of CD24/Siglec-10 but also PD-1/PD-L1. CSBP could induce the phagocytosis of tumor cell by both the macrophages and monocytic myeloid-derived suppressor cells (M-MDSCs), which can further activate CD8+ T cells. Besides, combination of radiotherapy and CSBP synergistically reduced tumor growth and altered the tumor microenvironment in both anti-PD-1-responsive MC38 and anti-PD-1-resistant 4T1 tumor models. CONCLUSIONS: In summary, this is the first CD24/Siglec-10 blocking peptide which blocked PD-1/PD-L1 interaction as well, functioned via enhancing the phagocytosis of tumor cells by macrophages and M-MDSCs, and elevating the activity of CD8+ T cells for cancer immunotherapy.

Peptide-based PET imaging agent of tumor TIGIT expression.

BACKGROUND: Accumulating studies have demonstrated that elevated TIGIT expression in tumor microenvironment correlates with better therapeutic response to TIGIT-based immunotherapy in pre-clinical studies. Therefore, a non-invasive method to detect tumor TIGIT expression is crucial to predict the therapeutic effect. METHODS: In this study, a peptide-based PET imaging agent, 68Ga-DOTA-DTBP-3, was developed to non-invasively detect TIGIT expression by micro-PET in tumor-bearing BALB/c mice. DTBP-3, a D-peptide comprising of 12 amino acids, was radiolabeled with 68Ga through a DOTA chelator. In vitro studies were performed to evaluate the affinity of 68Ga-DOTA-DTBP-3 to TIGIT and its stability in fetal bovine serum. In vivo studies were assessed by micro-PET, biodistribution, and immunohistochemistry on tumor-bearing BALB/c mice. RESULTS: The in vitro studies showed the equilibrium dissociation constant of 68Ga-DOTA-DTBP-3 for TIGIT was 84.21 nM and its radiochemistry purity was 89.24 ± 1.82% in FBS at 4 h in room temperature. The results of micro-PET, biodistribution and immunohistochemistry studies indicated that 68Ga-DOTA-DTBP-3 could be specifically targeted in 4T1 tumor-bearing mice, with a highest uptake at 0.5 h. CONCLUSION: 68Ga-DOTA-DTBP-3 holds potential for non-invasively detect tumor TIGIT expression and for timely assessment of the therapeutic effect of immune checkpoint blockade.

Identification of a novel small-molecule inhibitor targeting TIM-3 for cancer immunotherapy.

PD-1/PD-L1 blockade has achieved substantial clinical results in cancer treatment. However, the expression of other immune checkpoints leads to resistance and hinders the efficacy of PD-1/PD-L1 blockade. T cell immunoglobulin and mucin domain 3 (TIM-3), a non-redundant immune checkpoint, synergizes with PD-1 to mediate T cell dysfunction in tumor microenvironment. Development of small molecules targeting TIM-3 is a promising strategy for cancer immunotherapy. Here, to identify small molecule inhibitors targeting TIM-3, the docking pocket in TIM-3 was analyzed by Molecular Operating Environment (MOE) and the Chemdiv compound database was screened. The small molecule SMI402 could bind to TIM-3 with high affinity and prevent the ligation of PtdSer, HMGB1, and CEACAM1. SMI402 reinvigorated T cell function in vitro. In the MC38-bearing mouse model, SMI402 inhibited tumor growth by increasing CD8+ T and natural killing (NK) cells infiltration at the tumor site, as well as restoring the function of CD8+ T and NK cells. In conclusions, the small molecule SMI402 shows promise as a leading compound which targets TIM-3 for cancer immunotherapy.

Design of a novel chimeric peptide via dual blockade of CD47/SIRPα and PD-1/PD-L1 for cancer immunotherapy.

Although immune checkpoint inhibition has been shown to effectively activate antitumor immunity in various tumor types, only a small subset of patients can benefit from PD-1/PD-L1 blockade. CD47 expressed on tumor cells protects them from phagocytosis through interaction with SIRPα on macrophages, while PD-L1 dampens T cell-mediated tumor killing. Therefore, dual targeting PD-L1 and CD47 may improve the efficacy of cancer immunotherapy. A chimeric peptide Pal-DMPOP was designed by conjugating the double mutation of CD47/SIRPα blocking peptide (DMP) with the truncation of PD-1/PD-L1 blocking peptide OPBP-1(8-12) and was modified by a palmitic acid tail. Pal-DMPOP can significantly enhance macrophage-mediated phagocytosis of tumor cells and activate primary T cells to secret IFN-γ in vitro. Due to its superior hydrolysis-resistant activity as well as tumor tissue and lymph node targeting properties, Pal-DMPOP elicited stronger anti-tumor potency than Pal-DMP or OPBP-1(8-12) in immune-competent MC38 tumor-bearing mice. The in vivo anti-tumor activity was further validated in the colorectal CT26 tumor model. Furthermore, Pal-DMPOP mobilized macrophage and T-cell anti-tumor responses with minimal toxicity. Overall, the first bispecific CD47/SIRPα and PD-1/PD-L1 dual-blockade chimeric peptide was designed and exhibited synergistic anti-tumor efficacy via CD8+ T cell activation and macrophage-mediated immune response. The strategy could pave the way for designing effective therapeutic agents for cancer immunotherapy.

Integrative analysis of bulk and single-cell gene expression profiles to identify tumor-associated macrophage-derived CCL18 as a therapeutic target of esophageal squamous cell carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is a common gastrointestinal malignancy with poor patient prognosis. Current treatment for ESCC, including immunotherapy, is only beneficial for a small subset of patients. Better characterization of the tumor microenvironment (TME) and the development of novel therapeutic targets are urgently needed. METHODS: In the present study, we hypothesized that integration of single-cell transcriptomic sequencing and large microarray sequencing of ESCC biopsies would reveal the key cell subtypes and therapeutic targets that determine the prognostic and tumorigenesis of ESCC. We characterized the gene expression profiles, gene sets enrichment, and the TME landscape of a microarray cohort including 84 ESCC tumors and their paired peritumor samples. We integrated single-cell transcriptomic sequencing and bulk microarray sequencing of ESCC to reveal key cell subtypes and druggable targets that determine the prognostic and tumorigenesis of ESCC. We then designed and screened a blocking peptide targeting Chemokine C-C motif ligand 18 (CCL18) derived from tumor associated macrophages and validated its potency by MTT assay. The antitumor activity of CCL18 blocking peptide was validated in vivo by using 4-nitroquinoline-1-oxide (4-NQO) induced spontaneous ESCC mouse model. RESULTS: Comparative gene expression and cell-cell interaction analyses revealed dysregulated chemokine and cytokine pathways during ESCC carcinogenesis. TME deconvolution and cell interaction analyses allow us to identify the chemokine CCL18 secreted by tumor associated macrophages could promote tumor cell proliferation via JAK2/STAT3 signaling pathway and lead to poor prognosis of ESCC. The peptide Pep3 could inhibit the proliferation of EC-109 cells promoted by CCL18 and significantly restrain the tumor progression in 4-NQO-induced spontaneous ESCC mouse model. CONCLUSIONS: For the first time, we discovered and validated that CCL18 blockade could significantly prevent ESCC progression. Our study revealed the comprehensive cell-cell interaction network in the TME of ESCC and provided novel therapeutic targets and strategies to ESCC treatment.

Peptide vaccine from cancer-testis antigen ODF2 can potentiate the cytotoxic T lymphocyte infiltration through IL-15 in non-MSI-H colorectal cancer.

About 85% of patients with colorectal cancer (CRC) have the non-microsatellite instability-high (non-MSI-H) subtype, and many cannot benefit from immune checkpoint blockade. A potential reason for this is that most non-MSI-H colorectal cancers are immunologically "cold" due to poor CD8+ T cell infiltration. In the present study, we screened for potential cancer-testis antigens (CTAs) by comparing the bioinformatics of CD8+ T effector memory (Tem) cell infiltration between MSI-H and non-MSI-H CRC. Two ODF2-derived epitope peptides, P433 and P609, displayed immunogenicity and increased the proportion of CD8+ T effector memory (Tem) cells in vitro and in vivo. The adoptive transfer of peptide pool-induced CTLs inhibited tumor growth and enhanced CD8+ T cell infiltration in tumor-bearing NOD/SCID mice. The mechanistic study showed that knockdown of ODF2 in CRC cells promoted interleukin-15 expression, which facilitated CD8+ T cell proliferation. In conclusion, ODF2, a CTA, was negatively correlated with CD8+ T cell infiltration in "cold" non-MSI-H CRC and was selected based on the results of bioinformatics analyses. The corresponding HLA-A2 restricted epitope peptide induced antigen-specific CTLs. Immunotherapy targeting ODF2 could improve CTA infiltration via upregulating IL-15 in non-MSI-H CRC. This tumor antigen screening strategy could be exploited to develop therapeutic vaccines targeting non-MSI-H CRC.

Identification of natural product 3, 5-diiodotyrosine as APOBEC3B inhibitor to prevent somatic mutation accumulation and cancer progression.

BACKGROUND: The development of cancer is largely dependent on the accumulation of somatic mutations, indicating the potential to develop cancer chemoprevention agents targeting mutation drivers. However, ideal cancer chemoprevention agents that can effectively inhibit the mutation drivers have not been identified yet. METHODS: The somatic mutation signatures and expression analyses of APOBEC3B were performed in patient with pan-cancer. The computer-aided screening and skeleton-based searching were performed to identify natural products that can inhibit the activity of APOBEC3B. 4-nitroquinoline-1-oxide (4-NQO)-induced spontaneous esophageal squamous cell carcinoma (ESCC) and azoxymethane/dextran sulfate sodium (AOM/DSS)-induced spontaneous colon cancer mouse models were conducted to investigate the influences of APOBEC3B inhibitor on the prevention of somatic mutation accumulation and cancer progression. RESULTS: Here, we discovered that the cytidine deaminase APOBEC3B correlated somatic mutations were widely observed in a variety of cancers, and its overexpression indicated poor survival. SMC247 (3, 5-diiodotyrosine), as a source of kelp iodine without side effects, could strongly bind APOBEC3B (KD=65 nM) and effectively inhibit its deaminase activity (IC50=1.69 µM). Interestingly, 3, 5-diiodotyrosine could significantly reduce the clusters of mutations, prevent the precancerous lesion progression, and prolong the survival in 4-NQO-induced spontaneous ESCC and AOM/DSS-induced spontaneous colon cancer mouse models. Furthermore, 3, 5-diiodotyrosine could reduce colitis, increase the proportion and function of T lymphocytes via IL-15 in tumor microenvironment. The synergistic cancer prevention effects were observed when 3, 5-diiodotyrosine combined with PD-1/PD-L1 blockade. CONCLUSIONS: This is the first prove-of-concept study to elucidate that the natural product 3, 5-diiodotyrosine could prevent somatic mutation accumulation and cancer progression through inhibiting the enzymatic activity of APOBEC3B. In addition, 3, 5-diiodotyrosine could reduce the colitis and increase the infiltration and function of T lymphocytes via IL-15 in tumor microenvironment. 3, 5-diiodotyrosine combined with PD-1/PD-L1 blockade could elicit synergistic cancer prevention effects, indicating a novel strategy for both prevent the somatic mutation accumulation and the immune-suppressive microenvironment exacerbation.

A PD-L1 and VEGFR2 dual targeted peptide and its combination with irradiation for cancer immunotherapy.

Although the blockade of immune checkpoint PD-1/PD-L1 has achieved great success, the lack of tumor-infiltrating immune cells and PD-L1 expression in the tumor microenvironment results in a limited response in certain tumor types. Thus, rational and optimal combination strategies were urgently needed. The combination of PD-1/PD-L1 blockade and anti-angiogenic therapy has been reported to have great potential. Here, a chimeric peptide OGS was designed by conjugating the peptides OPBP-1 (8-12) and DA7R targeting PD-L1 and VEGFR2, respectively. OGS could bind to both human and mouse PD-L1 with high affinity and block the PD-1/PD-L1 interaction, and also inhibit the migration and tube formation of HUVEC cells in wound healing and tube formation assays. To further prolong the half-life of OGS, it was modified by coupling with peptide DSP which has a high binding affinity to both human serum albumin (HSA) and mouse serum albumin (MSA) to form the peptide DSPOGS. DSPOGS could not directly affect the viability, apoptosis, and cell cycle of tumor cells in vitro, while significantly inhibiting the tumor growth in the MC38 mouse model. DSPOGS could elicit a potent anti-tumor immune response and inhibit tumor angiogenesis, with the enhancement of tumor infiltrating CD8+ T cells and the IFN-γ secreting CD8+ T cells in the spleen and tumor-draining lymph node. Further, the combination of radiotherapy with DSPOGS could dramatically improve the therapeutic efficacy. Our study could provide a promising paradigm for the combination of immune checkpoint blockade, anti-angiogenesis, and radiotherapy.

Identification of Immune Subtypes of Esophageal Adenocarcinoma to Predict Prognosis and Immunotherapy Response.

A low response rate limits the application of immune checkpoint inhibitors (ICIs) in the treatment of esophageal adenocarcinoma (EAC), which requires the precise characterization of heterogeneous tumor microenvironments. This study aimed to identify the molecular features and tumor microenvironment compositions of EAC to facilitate patient stratification and provide novel strategies to improve clinical outcomes. Here, we performed consensus molecular subtyping with nonnegative matrix factorization (NMF) using EAC data from the Cancer Genome Atlas (TCGA) and identified two distinct subtypes with significant prognostic differences and differences in tumor microenvironments. The findings were further validated in independent EAC cohorts and potential response to ICI therapy was estimated using Tumor Immune Dysfunction and Exclusion (TIDE) and SubMap methods. Our findings suggest that EAC patients of subtype 2 with low levels of cancer-associated fibroblasts, tumor associated macrophages (TAMs), and MDSCs in the tumor microenvironment may benefit from PD-1 blockade therapy, while patients of subtype 1 are more responsive to chemotherapy or combination therapy. These findings might improve our understanding of immunotherapy efficacy and be useful in the development of new strategies to better guide immunotherapy and targeted therapy in the treatment of EAC.

Extracellular vesicle IL-32 promotes the M2 macrophage polarization and metastasis of esophageal squamous cell carcinoma via FAK/STAT3 pathway.

BACKGROUND: Metastasis is the leading cause of mortality in human cancers, including esophageal squamous cell carcinoma (ESCC). As a pro-inflammatory cytokine, IL-32 was reported to be a poor prognostic factor in many cancers. However, the role of IL-32 in ESCC metastasis remains unknown. METHODS: ESCC cells with ectopic expression or knockdown of IL-32 were established and their effects on cell motility were detected. Ultracentrifugation, Transmission electron microscopy and Western blot were used to verify the existence of extracellular vesicle IL-32 (EV-IL-32). Coculture assay, immunofluorescence, flow cytometry, and in vivo lung metastasis model were performed to identify how EV-IL-32 regulated the crosstalk between ESCC cells and macrophages. RESULTS: Here, we found that IL-32 was overexpressed and positively correlated to lymph node metastasis of ESCC. IL-32 was significantly higher in the tumor nest compared with the non-cancerous tissue. We found that IL-32ß was the main isoform and loaded in EV derived from ESCC cells. The shuttling of EV-IL-32 derived from ESCC cells into macrophages could promote the polarization of M2 macrophages via FAK-STAT3 pathway. IL-32 overexpression facilitated lung metastasis and was positively correlated with the proportion of M2 macrophages in tumor microenvironment. CONCLUSIONS: Taken together, our results indicated that EV-IL-32 derived from ESCC cell line could be internalized by macrophages and lead to M2 macrophage polarization via FAK-STAT3 pathway, thus promoting the metastasis of ESCC. These findings indicated that IL-32 could serve as a potential therapeutic target in patients with ESCC.

Screening and identification of HLA-A2-restricted neoepitopes for immunotherapy of non-microsatellite instability-high colorectal cancer.

Colorectal cancer has one of the highest mortality rates among malignant tumors, and most patients with non-microsatellite instability-high (MSI-H) colorectal cancer do not benefit from targeted therapy or immune checkpoint inhibitors. Identification of immunogenic neoantigens is a promising strategy for inducing specific antitumor T cells for cancer immunotherapy. Here, we screened potential high-frequency neoepitopes from non-MSI-H colorectal cancer and tested their abilities to induce tumor-specific cytotoxic T cell responses. Three HLA-A2-restricted neoepitopes (P31, P50, and P52) were immunogenic and could induce cytotoxic T lymphocytes in peripheral blood mononuclear cells from healthy donors and colorectal cancer patients. Cytotoxic T lymphocytes induced in HLA-A2.1/Kb transgenic mice could recognize and lyse mutant neoepitope-transfected HLA-A2+ cancer cells. Adoptive transfer of cytotoxic T lymphocytes induced by the peptide pool of these three neoepitopes effectively inhibited tumor growth and increased the therapeutic effects of anti-PD-1 antibody. These results revealed the potential of high-frequency mutation-specific peptide-based immunotherapy as a personalized treatment approach for patients with non-MSI-H colorectal cancer. The combination of adoptive T cell therapy based on these neoepitopes with immune checkpoint inhibitors, such as anti-PD-1, could provide a promising treatment strategy for non-MSI-H colorectal cancer.