Amphiregulin couples IL1RL1+ regulatory T cells and cancer-associated fibroblasts to impede antitumor immunity

Regulatory T (Treg) cells and cancer-associated fibroblasts (CAFs) jointly promote tumor immune tolerance and tumorigenesis. The molecular apparatus that drives Treg cell and CAF coordination in the tumor microenvironment (TME) remains elusive. Interleukin 33 (IL-33) has been shown to enhance fibrosis and IL1RL1+ Treg cell accumulation during tumorigenesis and tissue repair. We demonstrated that IL1RL1 signaling in Treg cells greatly dampened the antitumor activity of both IL-33 and PD-1 blockade. Whole tumor single-cell RNA sequencing (scRNA-seq) analysis and blockade experiments revealed that the amphiregulin (AREG)-epidermal growth factor receptor (EGFR) axis mediated cross-talk between IL1RL1+ Treg cells and CAFs. We further demonstrated that the AREG/EGFR axis enables Treg cells to promote a profibrotic and immunosuppressive functional state of CAFs. Moreover, AREG mAbs and IL-33 concertedly inhibited tumor growth. Our study reveals a previously unidentified AREG/EGFR-mediated Treg/CAF coupling that controls the bifurcation of fibroblast functional states and is a critical barrier for cancer immunotherapy.

Synergism Between IL21 and Anti-PD-1 Combination Therapy is Underpinned by the Coordinated Reprogramming of the Immune Cellular Network in the Tumor Microenvironment

T cell-stimulating cytokines and immune checkpoint inhibitors (ICI) are an ideal combination for increasing response rates of cancer immunotherapy. However, the results of clinical trials have not been satisfying. It is important to understand the mechanism of synergy between these two therapeutic modalities. Here, through integrated analysis of multiple single-cell RNA sequencing (scRNA-seq) datasets of human tumor-infiltrating immune cells, we demonstrate that IL21 is produced by tumor-associated T follicular helper cells and hyperactivated/exhausted CXCL13+CD4+ T cells in the human tumor microenvironment (TME). In the mouse model, the hyperactivated/exhausted CD4+ T cell-derived IL21 enhances the helper function of CD4+ T cells that boost CD8+ T cell-mediated immune responses during PD-1 blockade immunotherapy. In addition, we demonstrated that IL21's antitumor activity did not require T-cell trafficking. Using scRNA-seq analysis of the whole tumor-infiltrating immune cells, we demonstrated that IL21 treatment in combination with anti-PD-1 blockade synergistically drives tumor antigen-specific CD8+ T cells to undergo clonal expansion and differentiate toward the hyperactive/exhausted functional state in the TME. In addition, IL21 treatment and anti-PD-1 blockade synergistically promote dendritic cell (DC) activation and maturation to mature DC as well as monocyte to type 1 macrophage (M1) differentiation in the TME. Furthermore, the combined treatment reprograms the immune cellular network by reshaping cell-cell communication in the TME. Our study establishes unique mechanisms of synergy between IL21 and PD-1-based ICI in the TME through the coordinated promotion of type 1 immune responses.

Significance

This study reveals how cytokine and checkpoint inhibitor therapy can be combined to increase the efficacy of cancer immunotherapy.

Abstract 1326: Loss of p53 sensitizes tumor cells to immune checkpoint blockade therapy via upregulation of IL-33

Recent studies suggest p53 contributes to poor survival in the context of immune checkpoint blockade (ICB). Mutations to p53 significantly improve the response rate to PD-1 ICB in lung cancer patients. Tumor-derived IL-33 is required for the anti-tumor immune response and efficacy of ICB. However, the relationship between p53 and IL-33 during ICB is unknown. In this study, we characterize the role of the p53/IL-33 axis in regulating the response of the tumor microenvironment to ICB. We use CRISPR-Cas9 to delete Trp53 from murine MC38 colon adenocarcinoma. Deletion of Trp53 and PD-1 ICB synergistically inhibits tumor growth. Il33 is upregulated in the Trp53-deficient and treated tumor cells, and its expression increases with time and response to treatment. Cd4+ and Cd8+ T cell infiltration increases adjacent to IL-33 expressing tumor cells, while Treg infiltration is decreased. Simultaneous deletion of Il33 in MC38 tumors reverses the efficacy PD-1 ICB. Trp53-deficient MC38 in ST2-/- (IL-33 receptor) mice also show no response to PD-1 ICB. Our findings depict a novel mechanism by which the loss of p53 in tumors treated with ICB unleashes the expression of tumoral IL-33 and induces downstream signaling. p53 mutations may be a double-edged sword for cancer, i.e. the loss of the tumor suppressor initially facilitates tumorigenesis, but eventual buildup of mutations and activation of damage pathways, such as NF-kB, leads to upregulation of danger signals in the tumor. These danger signals, such as IL-33, mediate the anti-tumor effect of ICB.

Citation Format: David Shihong Gao, Yang Li, Jason Shoush, Runzi Sun, Binfeng Lu. Loss of p53 sensitizes tumor cells to immune checkpoint blockade therapy via upregulation of IL-33 [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 1326.

The Half-Life-Extended IL21 can Be Combined With Multiple Checkpoint Inhibitors for Tumor Immunotherapy

In the era of immune checkpoint blockade cancer therapy, cytokines have become an attractive immune therapeutics to increase response rates. Interleukin 21 (IL21) as a single agent has been evaluated for cancer treatment with good clinical efficacy. However, the clinical application of IL21 is limited by a short half-life and concern about potential immune suppressive effect on dendritic cells. Here, we examined the antitumor function of a half-life extended IL21 alone and in combination with PD-1 blockade using preclinical mouse tumor models. We also determined the immune mechanisms of combination therapy. We found that combination therapy additively inhibited the growth of mouse tumors by increasing the effector function of type 1 lymphocytes. Combination therapy also increased the fraction of type 1 dendritic cells (DC1s) and M1 macrophages in the tumor microenvironment (TME). However, combination therapy also induced immune regulatory mechanisms, including the checkpoint molecules Tim-3, Lag-3, and CD39, as well as myeloid derived suppressor cells (MDSC). This study reveals the mechanisms of IL21/PD-1 cooperation and shed light on rational design of novel combination cancer immunotherapy.

Development and application of sensitive, specific, and rapid CRISPR-Cas13-based diagnosis

Nucleic acid detection is a necessary part of medical treatment and fieldwork. However, the current detection technologies are far from ideal. A lack of timely and accessible testing for identifying cases and close contacts has allowed severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2), the causative virus of the ongoing coronavirus disease‐2019 (COVID‐19) pandemic, to spread uncontrollably. The slow and expensive detection of mutations—predictors for chronic diseases such as cancer—form a barrier to personalized treatment. A recently developed diagnostic assay is ideal and field‐ready—it relies on CRISPR‐Cas13. CRISPR‐Cas13 works similarly to other CRISPR systems: Cas13 is guided by a crRNA to cleave next to a specific RNA target sequence. Additionally, Cas13 boasts a unique collateral cleavage activity; collateral cleavage of a fluorescent reporter detects the presence of the target sequence in sample RNA. This system forms the basis of CRISPR‐Cas13 diagnostic assays. CRISPR‐Cas13 assays have >95% sensitivity and >99% specificity. Detection is rapid (<2 h), inexpensive ($0.05 per test), and portable—a test using lateral flow strips is akin to a pregnancy test. The recent adaptation of micro‐well chips facilitates high‐level multiplexing and is high‐throughput. In this review, we cover the development of CRISPR‐Cas13 assays for medical diagnosis, discuss the advantages of CRISPR‐Cas13‐based diagnosis over the traditional reverse transcription polymerase chain reaction (RT‐PCR), and present examples of detection from real patient samples.

In the CRISPR‐Cas13 system, Cas13 is guided by a crRNA to cleave sample RNA at a specific target sequence.

Cas13 has collateral cleavage activity that when used with a fluorescent reporter detects a specific target sequence.

CRISPR‐Cas13‐based diagnostics are highly sensitive (>95%), specific (>99%), rapid (<2 h), inexpensive ($0.05 per test), and portable‐recent adaptions of micro‐well chips facilitate high‐evel multiplexing and are high‐throughput.

CRISPR‐Cas13‐based diagnostics have been validated in the detection of viral RNA and mutations in patient samples, including SARS‐CoV‐2 RNA during the ongoing COVID‐19 pandemic.

CRISPR‐Cas13 is also applied to RNA editing, thereby creating a full system of diagnostics and therapeutics.

[Association between speed and endurance performance with sleep duration in children and adolescents]

OBJECTIVE

To analyze the association between sleep duration and athletic performance, and provide scientific basis to improve the 50 m and endurance performance in children and adolescents.

METHODS

All the 119 462 subjects aged 9-15 years in both genders were sampled from 2014 National Physical Fitness and Health Surveillance by using stratified random cluster sampling method, to measure the height, weight, 50 meters and endurance performance and investigate sleep duration with questionnaire. Their body mass indexes (BMI) were calculated and the students' 50 m, endurance run scores and sleep durations were assessed. Binary Logistic regression was used to analyze the difference between the different sleep groups, and multifactor Logistic regression was used to analyze the relationship between the sleep condition and athletic performance.

RESULTS

The prevalence of insufficient sleep was 94.67% in the total subjects, the prevalence was higher among the girls (95.26%)than the boys (94.09%, χ²=80.99, P<0.001), and higher among the urban (95.41%) than the rural students(93.93%, χ²=128.48, P<0.001).The children with sufficient sleep had better performance in 50 m and endurance run scores( χ²_{50 m}=10.10, P_{50 m}＜0.01; χ²_{endurance run}=21.76, P<0.001). Logistic regression analysis after controlling the gender, area, grade and BMI showed that children with adequate sleep showed better results(OR_{50 m}=1.14, 95%CI_{50 m}=1.05-1.23, P_{50 m}<0.01; OR_{endurance run}=1.21, 95%CI_{endurance run}=1.11-1.31, P_{endurance run}<0.001). As for gender, the excellent rates of 50 m and endurance run scores in the boys with adequate sleep were higher (P<0.001), but there were no significant difference in 50 m and endurance run excellent rates in the girls of different sleep conditions. The excellent rates of 50 m and endurance run in the urban children and the endurance rate in the rural children and adolescents with adequate sleep were higher than those with insufficient sleep (P<0.01) while there were no significant difference in the 50 m excellent rates between the different sleep groups in rural areas. The 50 m and endurance run excellent rates of the children and adolescents with adequate sleep in each grade were higher than those of the children in the same grade with insufficient sleep (P_{primary students' endurance performance}<0.001, and the rest P<0.05). Children and adolescents with normal BMI and overweight who slept well had better performance in 50 m (P<0.05). The endurance run excellent rate of children and adolescents with adequate sleep in each BMI group was higher than that in children and adolescents with insufficient sleep in the same BMI group (P_malnutrition<0.01, P_normal<0.01, P_overweight<0.05, P_obesity<0.05). The children and adolescents were divided into different groups according to the sleep duration,the one who slept less than 7 hours had lower 50 m excellent rate than the other groups with longer sleeping duration (P<0.01) and the rate in the ones who slept more than 9 hours was the highest (P<0.001).The endurance excellent rate in the children and adolescents who slept more than 9 hours was significantly higher than that in the other groups (P<0.001).There was no significant dose-response relationship in excellent rates and sleep durations.

CONCLUSION

The prevalence of insufficient sleep has increased, and the sleep condition in children and adolescents is severe. Children and adolescents with sufficient sleep have better athletic performance, so we should strengthen the prevention and control of the lack of sleep in children and adolescents.