Immunosuppressive Cells In Tumor Microenvironment Research Articles

Orchestrated copper-based nanoreactor for remodeling tumor microenvironment to amplify cuproptosis-mediated anti-tumor immunity in colorectal cancer

Owing to the deficiency of infiltrating immune cells and the accumulation of immunosuppressive cells in tumor microenvironment (TME), immunotherapy remains enormous challenges in colorectal cancer (CRC). Here, CRC was found to be sensitive to cuproptosis which could further evoke immune responses and mediate immune resistance. Thus, a cuproptosis-mediated immunotherapy nanoreactor (CCJD-FA) was constructed by encapsulating copper-based shell-coated CaO2 and bromodomain-containing protein 4 inhibitor JQ-1 with DSPE-PEG-FA. Within tumor cells, CCJD-FA was disassembled under GSH environment, and the exposed CaO2 could generate H2O2 under the acidic condition, which reacted with the released Cu2+ via Fenton-like reaction to produce O2 for relieving hypoxia and Cu+ for inducing cuproptosis. Furthermore, CCJD-FA could also inhibit intracellular glycolysis and ATP generation, then blocking the Cu+ efflux protein ATP7B. Meanwhile, the IFN-γ-induced PD-L1 expression could be exactly reduced by the BRD4 suppression and oxygen supply. These effects sensitized cancer cells to cuproptosis, further evoking systemic immune responses and reshaping immunosuppressive TME to inhibit tumor growth.

Abstract 5068: Nintedanib enhances antitumor effects of anti-PD-1 therapies through inhibition of immunosuppressive cells in tumor microenvironment

Abstract Background: Although programmed cell death-1 (PD-1) inhibitors have achieved promising and durable responses in patients with several types of cancer, many patients show intrinsic resistance to PD-1 inhibitors. Extensive studies have demonstrated that immunosuppressive cells are induced in tumor microenvironment and inhibit antitumor effects of PD-1 inhibitors. The aim of current study is to investigate whether nintedanib, which targets multi-tyrosine kinase including vascular endothelial growth factor, fibroblast growth factor, and platelet-derived growth factor, reduced immunosuppressive cells in tumor microenvironment and augments antitumor effects of PD-1 inhibitors. Method: Mice were inoculated subcutaneously with CT26 murine colon carcinoma or MC38 murine colon carcinoma and were treated with nintedanib (50 mg/kg), αPD-1mAbs (10 mg/kg) or nintedanib plus αPD-1mAbs. The tumor size was measured in 2 perpendicular dimensions 3 times per week. Types of cells infiltrating into tumors and immune status of tumor-draining lymph nodes were assessed using flow cytometry and immunohistochemistry (IHC). Results: RNA sequencing data revealed that nintedanib decreased gene expression related to endothelial mesenchymal transition, angiogenesis and coagulation. Flow cytometry showed that nintedanib significantly decreased the percentage of myeloid-derived suppressor cells and cancer-associated fibroblast in tumor tissues. Both of flow cytometry and IHC analysis showed that nintedanib significantly increased IFN-ϒ+CD4+ and CD8+ T cells infiltrating in tumors. In addition, nintedanib plus αPD-1mAbs significantly retarded tumor progression. Conclusion: Nintedanib decreased immunosuppressive cells, increased effector T cells, and enhanced anti-tumor effects of αPD-1mAbs. Based on these findings, there are possibility that nintedanib improves clinical outcomes of cancer patients treated with PD-1 inhibitors. Citation Format: Ryo Suzuki, Satoshi Watanabe, Kunihiro Shono, Takaaki Masuda, Tomoki Sekiya, Yuka Goto, Toshiya Fujisaki, Masashi Arita, Aya Ohtsubo, Satoshi Shoji, Tomohiro Tanaka, Koichiro Nozaki, Rie Kondo, Yu Saida, Satoshi Hokari, Riuko Ohashi, Kenjiro Shima, Yosuke Kimura, Nobumasa Aoki, Yasuyoshi Ohshima, Toshiyuki Koya, Toshiaki Kikuchi. Nintedanib enhances antitumor effects of anti-PD-1 therapies through inhibition of immunosuppressive cells in tumor microenvironment. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5068.

Research Progress of Regulatory T Cells in the Pathogenesis of Multiple Myeloma --Review

The multiple myeloma (MM), the second most common hematologic malignancy, is malignant proliferative disease of plasma cells. Although the application of many targeted drugs has significantly prolonged the survival time of MM patients, it is still an incurable disease. In recent years, the immunosuppression caused by interaction between tumor microenvironment(TME) and tumor cells has attracted people's attention gradually. As a kind of immunosuppressive cells in TME, regulatory T cells (Treg) play an important role in the progress of MM. Treg is related to the proliferation and metastasis of tumors, and can lead to the progress of MM by promoting the angiogenesis and generating immunosuppressive TME. In this review, we briefly summarized the latest research progress on the impact of Treg on the pathogenesis of MM.

Abstract 3887: β3-adrenergic receptor sustains IFN-γ-dependent PD-L1 expression and impairs anti-tumor immunity in neuroblastoma

Abstract In this study we aimed to investigate the role of the β3-adrenergic receptor (β3-AR) in regulating the immune system response against neuroblastoma (NB) tumor. NB is a very heterogeneous extracranial tumor occurring in childhood. A distinctive feature of NB tumors is their neuroendocrine ability to secrete catecholamines, which in turn, via β-adrenergic receptors ligation, may affect different signaling pathways in the tumor microenvironment (TME). We previously demonstrated that the specific antagonism of the β3-AR on NB tumor cells affected tumor growth and progression. Here, in a murine syngeneic model of NB (A/J mice inoculated with the murine neuroblastoma cell line Neuro-2a), the β3-AR blockade ability to influence the number of immunoreactive and/or immunosuppressive cells in TME was investigated through flow cytometry analysis. Moreover, the involvement of the immune-checkpoint signaling axis PD-1/PD-L1 in mediating the anti-tumoral effects brought by a β3-AR antagonist administration was analyzed. Results demonstrated that β3-AR antagonism leads to an immune response reactivation, partially dependent on the PD-1/PD-L1 signaling axis involvement. Indeed, β3-AR antagonism was able to increase the number of immune reactive CD8+, natural killer (NK) and dendritic cells (DCs), and to decrease the number of immune suppressive regulatory T cells (Treg) and Myeloid-derived suppressor cells (MDSC) in tumor mass. Moreover, β3-AR blockade on tumor infiltrating lymphocytes (TILs) dampened their ability to secrete IFN-γ, which in turn reduced the PD-L1 expression on NB tumor cells. Further investigations, through a genomic analysis on NB patients, showed that high ADRB3 gene expression correlates negatively with the patient’s clinical outcome compared to the low expression group, and that ADRB3 gene expression is also related to the expression of different immune-checkpoints. Overall, results indicate that β3-AR in NB TME is able to modulate the interaction between tumor and host immune system, and that its antagonism hits multiple pro-tumoral signaling pathways. Citation Format: Gennaro Bruno, Nicoletta Nastasi, Angela Subbiani, Alessia Boaretto, Annalisa Tondo, Claudio Favre, Maura Calvani. β3-adrenergic receptor sustains IFN-γ-dependent PD-L1 expression and impairs anti-tumor immunity in neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3887.

Myeloid derived suppressor cells contribute to the malignant progression of oral squamous cell carcinoma.

PurposeThe tumor-related myeloid derived suppressor cells (MDSCs), important immunosuppressive cells in tumor microenvironment, play an important role in the cancer progression. This study is aimed to investigate the crosstalk between MDSCs and oral squamous cell carcinoma (OSCC) cells and their role in the malignant progression of OSCC.MethodsImmunochemistry (IHC) was used to investigate the expression of CD33 in 200 OSCC, 36 premalignant. CD33+ MDSCs were sorted and enriched via magnetic-activated cell sorting (MACS) from OSCC patients or health donor, and their phenotypes were identified by flow cytometry. With a co-culture system of MDSCs and OSCC, the effects of MDSCs on OSCC proliferation, apoptosis, migration invasion, epithelial-mesenchymal transition (EMT), and vasculogenic mimicry formation (VM) formation were assessed, respectively. Besides, peripheral blood mononuclear cells (PBMCs) from health donor were cultured with OSCC supernatant, the level of MDSCs and expressions of Arginase (Arg-1) and inducible nitric oxide synthase (iNOS) were measured.ResultsThe number of MDSCs was increased in tumor tissues of OSCC patients, and was positively related to the T stage, pathological grade, lymph node metastasis and poor prognosis. Tumor-related MDSCs of the co-culture system promoted OSCC progression by contributing to cell proliferation, migration and invasion as well as inducing EMT and VM. In turn, OSCC cells had potential to induce MDSCs differentiation from PBMCs and increase the expression of Arg-1 and iNOS.ConclusionThese indicated that the crosstalk between MDSCs and tumor cells facilitated the malignant progression of OSCC cells and the immune suppressive properties of MDSCs, which may provide new insights into tumor treatment on targeting tumor-associated immunosuppressive cells.

Sequential depletion of myeloid-derived suppressor cells and tumor cells with a dual-pH-sensitive conjugated micelle system for cancer chemoimmunotherapy

Myeloid-derived suppressor cells(MDSCs)are one of the most important immunosuppressive cells in tumor microenvironment, which also promote the development and progression of tumor cells. Nevertheless, due to the different distribution features of MDSCs and tumor cells, selective elimination of MDSCs and tumor cells in tumor microenvironment remain a great challenge. Here we have designed a dual-pH-sensitivity conjugated micelle system (PAH/RGX-104@PDM/PTX) that could deliver liver-X nuclear receptor (LXR) agonist RGX-104 and paclitaxel (PTX) to the perivascular region and tumor cells, respectively. Upon arrival at the acidic tumor microenvironment, the PAH/RGX-104@PDM/PTX undergo structure disintegration and capacitate coinstantaneous release of RGX-104 in the perivascular regions, leaving the intact PTX containing micelles PDM/PTX for tumor deep penetration. The released RGX-104 can be preferentially taken up by leukocytes, endothelial cells and macrophages which are nicely enriched in perivascular regions to active the LXR, and further reduces immunosuppressive MDSC levels. The remained small micelles carrying PTX enable deep tumor penetration as well as rapid specific drug release in the endosomal/lysosomal to kill tumor cells. PAH/RGX-104@PDM/PTX exhibits superior tumor accumulation as well as tumor penetration, and suppresses 74.88% in vivo tumor growth. More importantly, PAH/RGX-104@PDM/PTX has significantly alleviated tumor immunosuppression by eliminating MDSCs and increasing cytotoxic T lymphocytes infiltration. Our studies suggest that the dual-pH-sensitive codelivery nanocarrier not only cause apoptosis of cancer cells but also regulate the tumor immune environment to ultimately enhance the antitumor effect of CTLs through MDSCs depletion.

Theophylline induces differentiation and modulates cytoskeleton dynamics and cytokines secretion in human melanoma-initiating cells

AimsCutaneous melanoma is the most aggressive skin cancer, derived from neoplastic transformation of melanocytes. Since several evidences highlighted the importance of a hierarchical model of differentiation among cancer cells, closely related to resistance mechanisms and tumor relapse, we investigated the effects of theophylline (Theo), a methylxanthine commonly used in treatment of respiratory diseases, on melanoma cells with different degree of differentiation, including patient-derived melanoma-initiating cells. Materials and methodsThe antiproliferative and antimetastatic effects of Theo was demonstrated by cell counting, adhesion and migration assays on A375 and SK-MEL-30 cells. Further, Theo ability to reduce cell growth was highly significant in A375-derived spheroids and in two patient-derived melanoma-initiating cells (MICs). In order to identify pathways potentially involved in the antineoplastic properties of Theo, a comparative mass spectrometry proteomic analysis was used. Then, melanin content, tyrosinase and tissue transglutaminase activities as differentiation markers and actin re-organization through confocal microscopy were evaluated. Furthermore, a secretome profile of MICs after Theo treatments was performed by multiplex immunoassay. Key findingsObtained results demonstrate inhibitory effects of Theo on melanoma cell proliferation and migration, mainly in MICs, together with the induction of differentiation parameters. Moreover, our data indicate that the known anti-melanoma effect of Theo is due also to its ability to interfere with cytoskeleton dynamics and to induce the secretion of inflammatory molecules involved in recruitment of immunosuppressive cells in tumor microenvironment. SignificanceData strongly suggest that Theo supplement, either as drug or as dietary supply, may represent a potent additional weapon against melanoma.

Functional Regulation of Ginsenosides on Myeloid Immunosuppressive Cells in the Tumor Microenvironment.

Ginsenosides, the key components isolated from ginseng, have been extensively studied in antitumor treatment. Numerous studies have shown that ginsenosides have direct function in tumor cells through the induction of cancer cell apoptosis and the inhibition of cancer cell growth and enhance the antitumor immunity through the activation of cytotoxic T lymphocytes and natural killer cells. However, little is known about the function of ginsenosides on myeloid immunosuppressive cells including dendritic cells in tumor, tumor-associated macrophages, and myeloid-derived suppressor cells in the tumor microenvironments. Those myeloid immunosuppressive cells play important roles in promoting tumor angiogenesis, invasion, and metastasis. In the review, we summarize the regulatory functions of ginsenosides on myeloid immunosuppressive cells in tumor microenvironment, providing the novel therapeutic methods for clinical cancer treatment.

Plasmacytoid Dendritic Cells and ICOS+ Regulatory T Cells Predict Poor Prognosis in Gastric Cancer: A Pilot Study

Background: Regulatory T cells (Tregs) and plasmacytoid dendritic cells (pDCs) are the main immunosuppressive cells in tumor microenvironment of gastric cancer (GC). In this prospective study, the association of prognosis with Tregs subsets and pDCs were further analyzed.Methods: pDCs, Tregs population and its expression of inducible costimulator (ICOS) were analyzed in peripheral blood from 41 GC patients by multicolor flow cytometry. These cell populations in carcinoma tissue, peritumor tissue and normal gastric mucosa from 87 GC patients were also detected by immunohistochemistry and double immunofluorescence.Results: Both ICOS+Foxp3+Treg cells (P=0.0341 and P=0.0298, respectively) and pDC (P=0.0237 and P=0.0083, respectively) in peripheral blood and tumor tissue could predict poor clinical outcome in GC patients. However, the total Foxp3+Tregs in the GC tissue didn't correlated with the outcome (P=0.4299). No correlation of CD4+ T cell or CD8+ T cell frequency could be found with clinical outcome neither in peripheral blood nor in tumor tissue.Conclusions: ICOS+Tregs and pDCs could predict poor prognosis of GC, targeting ICOS-L/ICOS costimulation axis may be a potential treatment for GC.

Abstract 2828: miR-19a-3p inhibits breast carcinoma metastasis via reversing M2 phenotype of TAMs.

Abstract Tumor-associated macrophages (TAMs), most of which exhibit M2 phenotype, function as immunosuppressive cells in tumor microenvironment (TME). Polarization of TAMs from a pro-immune (M1 like) phenotype to an immune-suppressive (M2-like) phenotype is one of the hallmarks of malignancy, but their molecular basis is still remains unknown. It has been reported that microRNAs are involved in monocyte-macrophage differentiation. In this study, we found that miR-19a-3p, broadly conserved in vertebrate, could reverse the M2 phenotype of RAW macrophage cells. When mouse breast tumor cells such as 4T1, 4TO7 and EMT6 were co-cultured with RAW macrophage cells which over express miR-19a-3p, the invasion capacity was suppressed. Meanwhile, when the conditional medium of RAW cells which were transfected with miR-19a-3p mimic was added into culturing medium of tumor cells, the migration capacity of 4T1 and EMT6 breast cancer cells was inhibited. Moreover, when miR-19a-3p was injected intratumor, consistent with the in vitro experiments, we found that the M2 phenotype of TAMs was suppressed significantly. Although 4T1 xengraft breast tumor growth was not affected by miR-19a-3p, lung metastasis of tumor cells was significantly suppressed. Taken together, our findings indicate that miR-19a-3p is down-regulated in M2 phenotype RAW macrophage and TAMs in TME. The low expression of miR-19a-3p plays an important role in inducing M2 macrophage polarization and promoting migration and invasion capacity and metastasis. Citation Format: Jian Yang, Na Li, Zhuhong Zhang, Qin Si, Chong Chen, Yan Liu, Ralph A. Reisfeld, Peiqing Sun, Dwayne Stupack, Rong Xiang, Yunping Luo. miR-19a-3p inhibits breast carcinoma metastasis via reversing M2 phenotype of TAMs. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2828. doi:10.1158/1538-7445.AM2013-2828 Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.

Identifying drug toxicity

Myeloid-derived suppressor cells(MDSCs)are one of the most important immunosuppressive cells in tumor microenvironment, which also promote the development and progression of tumor cells. Nevertheless, due to the different distribution features of MDSCs and tumor cells, selective elimination of MDSCs and tumor cells in tumor microenvironment remain a great challenge. Here we have designed a dual-pH-sensitivity conjugated micelle system (PAH/[email protected]/PTX) that could deliver liver-X nuclear receptor (LXR) agonist RGX-104 and paclitaxel (PTX) to the perivascular region and tumor cells, respectively. Upon arrival at the acidic tumor microenvironment, the PAH/[email protected]/PTX undergo structure disintegration and capacitate coinstantaneous release of RGX-104 in the perivascular regions, leaving the intact PTX containing micelles PDM/PTX for tumor deep penetration. The released RGX-104 can be preferentially taken up by leukocytes, endothelial cells and macrophages which are nicely enriched in perivascular regions to active the LXR, and further reduces immunosuppressive MDSC levels. The remained small micelles carrying PTX enable deep tumor penetration as well as rapid specific drug release in the endosomal/lysosomal to kill tumor cells. PAH/[email protected]/PTX exhibits superior tumor accumulation as well as tumor penetration, and suppresses 74.88% in vivo tumor growth. More importantly, PAH/[email protected]/PTX has significantly alleviated tumor immunosuppression by eliminating MDSCs and increasing cytotoxic T lymphocytes infiltration. Our studies suggest that the dual-pH-sensitive codelivery nanocarrier not only cause apoptosis of cancer cells but also regulate the tumor immune environment to ultimately enhance the antitumor effect of CTLs through MDSCs depletion.