Enriching CCL3 in the Tumor Microenvironment Facilitates T cell Responses and Improves the Efficacy of Anti-PD-1 Therapy

Chronic Stress Exacerbates the Immunosuppressive Microenvironment and Progression of Gliomas by Reducing Secretion of CCL3

As understanding of cancer has deepened, increasing attention has been turned to the roles of psychological factors, especially chronic stress-induced depression, in the occurrence and development of tumors. However, whether and how depression affects the progression of gliomas are still unclear. In this study, we have revealed that chronic stress inhibited the recruitment of tumor-associated macrophages (TAM) and other immune cells, especially M1-type TAMs and CD8+ T cells, and decreased the level of proinflammatory cytokines in gliomas, leading to an immunosuppressive microenvironment and glioma progression. Mechanistically, by promoting the secretion of stress hormones, chronic stress inhibited the secretion of the chemokine CCL3 and the recruitment of M1-type TAMs in gliomas. Intratumoral administration of CCL3 reprogrammed the immune microenvironment of gliomas and abolished the progression of gliomas induced by chronic stress. Moreover, levels of CCL3 and M1-type TAMs were decreased in the tumor tissues of glioma patients with depression, and CCL3 administration enhanced the antitumor effect of anti-PD-1 therapy in orthotopic models of gliomas undergoing chronic stress. In conclusion, our study has revealed that chronic stress exacerbates the immunosuppressive microenvironment and progression of gliomas by reducing the secretion of CCL3. CCL3 alone or in combination with an anti-PD-1 may be an effective immunotherapy for the treatment of gliomas with depression. See related Spotlight by Cui and Kang, p. 514.

Identification of immune-related hub genes and construction of an immune-related gene prognostic index for low-grade glioma

Low-grade glioma (LGG) poses significant management challenges and has a dismal prognosis. While immunotherapy has shown significant promise in cancer treatment, its progress in glioma has confronted with challenges. In our study, we aimed to develop an immune-related gene prognostic index (IRGPI) which could be used to evaluate the response and efficacy of LGG patients with immunotherapy. We included a total of 529 LGG samples from TCGA database and 1152 normal brain tissue samples from the GTEx database. Immune-related differentially expressed genes (DEGs) were screened. Then, we used weighted gene co-expression network analysis (WGCNA) to identify immune-related hub genes in LGG patients and performed Cox regression analysis to construct an IRGPI. The median IRGPI was used as the cut-off value to categorize LGG patients into IRGPI-high and low subgroups, and the molecular and immune mechanism in IRGPI-defined subgroups were analysed. Finally, we explored the relationship between IRGPI-defined subgroups and immunotherapy related indicators in patients after immunotherapy. Three genes (RHOA, NFKBIA and CCL3) were selected to construct the IRGPI. In a survival analysis using TCGA cohort as a training set, patients in the IRGPI-low subgroup had a better OS than those in IRGPI-high subgroup, consistent with the results in CGGA cohort. The comprehensive results showed that IRGPI-low subgroup had a more abundant activated immune cell population and lower TIDE score, higher MSI, higher TMB score, lower T cell dysfunction score, more likely benefit from ICIs therapy. IRGPI is a promising biomarker in the field of LGG ICIs therapy to distinguish the prognosis, the molecular and immunological characteristics of patients.

Quantifying the impact of immunotherapy on RNA dynamics in cancer

BACKGROUND

Checkpoint inhibitor (CPI) immunotherapies have provided durable clinical responses across a range of solid tumor types for some patients with cancer. Nonetheless, response rates to CPI vary greatly between cancer types. Resolving intratumor transcriptomic changes induced by CPI may improve our understanding of the mechanisms of sensitivity and resistance.

METHODS

We assembled a cohort of longitudinal pre-therapy and on-therapy samples from 174 patients treated with CPI across six cancer types by leveraging transcriptomic sequencing data from five studies.

RESULTS

Meta-analyses of published RNA markers revealed an on-therapy pattern of immune reinvigoration in patients with breast cancer, which was not discernible pre-therapy, providing biological insight into the impact of CPI on the breast cancer immune microenvironment. We identified 98 breast cancer-specific correlates of CPI response, including 13 genes which are known IO targets, such as toll-like receptors TLR1, TLR4, and TLR8, that could hold potential as combination targets for patients with breast cancer receiving CPI treatment. Furthermore, we demonstrate that a subset of response genes identified in breast cancer are already highly expressed pre-therapy in melanoma, and additionally we establish divergent RNA dynamics between breast cancer and melanoma following CPI treatment, which may suggest distinct immune microenvironments between the two cancer types.

CONCLUSIONS

Overall, delineating longitudinal RNA dynamics following CPI therapy sheds light on the mechanisms underlying diverging response trajectories, and identifies putative targets for combination therapy.

Construction of a novel prognostic model in skin cutaneous melanoma based on chemokines-related gene signature

Skin cutaneous melanoma, SKCM, is one of the most aggressive treatment-resistant tumours. Despite the fact that the BRAF oncogene and immunological checkpoints such as PD-1/PD-L1 and CTLA-4 have enhanced the therapeutic efficacy of SKCM, the subsequent resistance mechanisms and remedies have raised concerns. Chemokines have a significant role in the immunological milieu of tumor, which may increase the efficacy of checkpoint blockade and serve as a possible therapeutic intervention route. However, there is still no chemokine-based typing and risk model to provide a prognosis and therapeutic efficacy assessment for SKCM patients. In this study, we verified the distinct differences of prognostic stratification as well as immune characteristics between two chemokine-related clusters in SKCM patients. Two clusters of DEGs were discovered to be primarily enriched in B and T cell receptor signaling pathways as well as TNF signaling via NF-kappa-B. Based on 14 prognosis-related DEGs from aforementioned two clusters (CCL8, GBP2, GBP4, SRNG, HLA-DMB, RARRES3, HLA-DQA1, PARP12, APOL3, IRF1, HLA-DRA, UBE2L6, IL2RA and CD38), a chemokine-related 14-gene prognostic model was established. At the same time, researchers explored differences between the low-risk and high-risk groups in clinical traits, the proportion of infiltration of 22 different types of immune cells, and how well medications worked. The risk score model's immunotherapy and prognostic predictions were also confirmed in testing groups. Based on the finding, we can claim that there is a clear link between chemokines and TME in SKCM. The risk score may perform as a trustworthy prediction model, giving therapeutic benefits for both chemotherapy and immunotherapy, as well as being beneficial for clinical decision making in SKCM patients.

CD103+ Cells and Chemokine Receptor Expression in Breast Cancer

Mucosal environments harbour lymphocytes, which express several adhesion molecules, including intestinal homing receptors and integrin αE/β7 (CD103). CD103 binds E-cadherin, an integrin receptor expressed in intestinal endothelial cells. Its expression not only enables homing or retention of T lymphocytes at these sites but is also associated with increased T lymphocyte activation. However, it is not yet clear how CD103 expression is related to the clinical staging of breast cancer, which is determined by factors such as the size of the tumor (T), the involvement of nearby lymph nodes (N), and presence of metastasis (M). We examined the prognostic significance of CD103 by FACS in 53 breast cancer patients and 46 healthy controls enrolled, and investigated its expression, which contributes to lymphocyte recruitment in tumor tissue. Patients with breast cancer showed increased frequencies of CD103⁺, CD4⁺CD103⁺, and CD8⁺CD103⁺ cells compared to controls. CD103 was expressed at a high level on the surfaces of tumor-infiltrating lymphocytes in patients with breast cancer. Its expression in peripheral blood was not correlated with clinical TNM stage. To determine the localisation of CD103⁺ cells in breast tissue, tissue sections of breast tumors were stained for CD103. In tissue sections of breast tumors stained for CD103, its expression in T lymphocytes was higher compared to normal breast tissue. In addition, CD103⁺ cells expressed higher levels of receptors for inflammatory chemokines, compared to CD103^- cells. CD103⁺ cells in peripheral blood and tumor tissue might be an important source of tumor-infiltrating lymphocyte trafficking, homing, and retention in cancer patients.

CCL3-CCR5 axis promotes cell migration and invasion of colon adenocarcinoma via Akt signaling pathway

BACKGROUND

Infiltration of tumor-associated macrophages (TAMs) can promote tumorigenesis and development. C-C motif chemokine ligand 3 (CCL3) was reported to be derived from TAMs and tumor cells and facilitate the progression of several cancers. Nevertheless, whether CCL3 can be derived from TAMs and tumor cells of colon adenocarcinoma (COAD) is unclarified.

METHODS

Peripheral blood monocytes-derived macrophages were polarized by the conditioned medium from COAD cells to establish TAM-like macrophages (TAM1/2). RT-qPCR and western blotting were used for detection of expression levels of CCL3 and its receptors C-C motif chemokine receptor 1 (CCR1) and CCR5 in TAM1/2 and COAD cells. Immunofluorescence staining was utilized for evaluating CCL3, CD163 and CCR5 expression. The Akt signaling pathway-associated protein levels were measured by western blotting. Transwell assays were used for assessing cell migration and invasiveness.

RESULTS

CCL3 displayed a high level in TAMs and cancer cells of COAD. CCL3 activated the Akt signaling pathway by binding to CCR5. CCL3-CCR5 axis facilitated COAD cell migration and invasiveness by activating the Akt signaling. CCL3 derived from both TAMs and cancer cells contributed to the malignant behaviors of COAD cells. High expression of CCL3/CCR5 was closely associated with poor prognoses of COAD patients.

CONCLUSION

CCL3-CCR5 interaction promotes cell migration and invasiveness, and functions as a prognostic biomarker for COAD.

Tumor Immunogenic Cell Death as a Mediator of Intratumor CD8 T-Cell Recruitment

The success of anticancer treatments relies on a long-term response which can be mediated by the immune system. Thus, the concept of immunogenic cell death (ICD) describes the capacity of dying cancer cells, under chemotherapy or physical stress, to express or release danger-associated molecular patterns (DAMPs). These DAMPs are essential to activate dendritic cells (DCs) and to stimulate an antigen presentation to CD8 cytotoxic cells. Then, activated CD8 T cells exert their antitumor effects through cytotoxic molecules, an effect which is transitory due to the establishment of a feedback loop leading to T-cell exhaustion. This phenomenon can be reversed using immune checkpoint blockers (ICBs), such as anti-PD-1, PD-L1 or CTLA-4 Abs. However, the blockade of these checkpoints is efficient only if the CD8 T cells are recruited within the tumor. The CD8 T-cell chemoattraction is mediated by chemokines. Hence, an important question is whether the ICD can not only influence the DC activation and resulting CD8 T-cell activation but can also favor the chemokine production at the tumor site, thus triggering their recruitment. This is the aim of this review, in which we will decipher the role of some chemokines (and their specific receptors), shown to be released during ICD, on the CD8 T-cell recruitment and antitumor response. We will also analyze the clinical applications of these chemokines as predictive or prognostic markers or as new targets which should be used to improve patients' response.

MIP-1α Level and Its Correlation with the Risk of Left Atrial Remodeling in Patients with Atrial Fibrillation

The aim of this study is to investigate the expression level of macrophage inflammatory protein-1α (MIP-1α) in atrial fibrillation patients and its correlation with the risk of left atrial remodeling. A total of 64 atrial fibrillation patients admitted to our hospital from April 2020 to December 2021 were prospectively selected as the case group and 61 healthy subjects who received physical examination during the same period were selected as the control group. Serum MIP-1α level was determined by a double-antibody sandwich enzyme-linked immunosorbent assay. Serum MIP-1α expression levels were compared between the case and the control groups. The case group was divided into high-level and low-level groups according to the serum MIP-1α median. Simultaneously, the sociodemographic data, clinical data, and left atrial remodeling indexes of the patients were collected in the case group. The Pearson correlation analysis was applied to analyze the correlation between the serum MIP-1α level and the risk of left atrial remodeling in patients with atrial fibrillation. The serum MIP-1α level was significantly higher in the case group than that in the control group (P < 0.05), high-level group (≥2.14 pg/mL, 32 cases), and low-level group (<2.14 pg/mL, 32 cases). There were significant differences in the anteroposterior diameter, upper and lower diameter, left and right diameter of the left atrium, left atrial volume, volume index, left atrial global ejection fraction, and sphericity between the low-level and high-level groups (P < 0.05). The Pearson correlation analysis showed that serum MIP-1α level was positively correlated with the left atrial anteroposterior diameter (r = 0.745), left atrial left and right diameter (r = 0.759), left atrial upper and lower diameter (r = 0.810), left atrial volume (r = 0.837), left atrial volume index (r = 0.813), and left atrial sphericity (r = 0.785) but negatively correlated with the left atrial global ejection fraction (r = -0.731) (P < 0.05). The expression level of serum MIP-1α is high in atrial fibrillation patients and is associated with the risk of left atrial remodeling.