Activation of Gasdermin D (GSDMD) results in its cleavage, oligomerization, and subsequent formation of plasma membrane pores, leading to a form of inflammatory cell death denoted as pyroptosis. The roles of GSDMD in inflammation and immune responses to infection are well documented. However, whether GSDMD also plays a role in sporadic cancer development, especially that in the gut epithelium, remains unknown. Here, we show that GSDMD is activated in colorectal tumors of both human and mouse origins. Ablation of GSDMD in a mouse model of sporadic colorectal cancer resulted in reduced tumor formation in the colon and rectum, suggesting a tumor-promoting role of the protein in the gut. Both antibiotic-mediated depletion of gut microbiota and pharmacological inhibition of NLRP3 inflammasome reduced the activation of GSDMD. Loss of GSDMD resulted in reduced infiltration of immature myeloid cells, and increased numbers of macrophages in colorectal tumors. Activation of GSDMD is also accompanied by the aggregation of the endosomal sorting complex required for transport (ESCRT) membrane repair proteins on the membrane of colorectal tumor cells, suggesting that active membrane repairment may prevent pyroptosis induced by the formation of GSDMD pore in tumor cells. Our results show that gut microbiota/NLRP3-mediated activation of GSDMD promotes the development of colorectal tumors, and supports the use of NLRP3 inhibitors to treat colon cancer.

Ethnopharmacological relevance: Rujifang (RJF) constitutes a traditional Chinese medicinal compound extensively employed in the management of triple-negative breast cancer (TNBC). However, information regarding its potential active ingredients, antitumor effects, safety, and mechanism of action remains unreported. Aim of the study: To investigate the efficacy and safety of RJF in the context of TNBC. Materials and methods: We employed the ultra high-performance liquid chromatography-electrospray four-pole time-of-flight mass spectrometry technique (UPLC/Q-TOF-MS/MS) to scrutinize the chemical constituents of RJF. Subcutaneously transplanted tumor models were utilized to assess the impact of RJF on TNBC in vivo. Thirty female BLAB/c mice were randomly divided into five groups: the model group, cyclophosphamide group, and RJF high-dose, medium-dose, and low-dose groups. A total of 1 x 106 4T1 cells were subcutaneously injected into the right shoulder of mice, and they were administered treatments for a span of 28 days. We conducted evaluations on blood parameters, encompassing white blood cell count (WBC), red blood cell count (RBC), hemoglobin (HGB), platelet count (PLT), neutrophils, lymphocytes, and monocytes, as well as hepatorenal indicators including alkaline phosphatase (ALP), glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), albumin, and creatinine (CRE) to gauge the safety of RJF. Ki67 and TUNEL were detected via immunohistochemistry and immunofluorescence, respectively. We prepared RJF drug-containing serum for TNBC cell lines and assessed the in vitro inhibitory effect of RJF on tumor cell growth through the CCK8 assay and cell cycle analysis. RT-PCR was employed to detect the mRNA expression of cyclin-dependent kinase and cyclin-dependent kinase inhibitors in tumor tissues, and Western blot was carried out to ascertain the expression of cyclin and pathway-related proteins. Results: 100 compounds were identified in RJF, which consisted of 3 flavonoids, 24 glycosides, 18 alkaloids, 3 amino acids, 8 phenylpropanoids, 6 terpenes, 20 organic acids, and 18 other compounds. In animal experiments, both CTX and RJF exhibited substantial antitumor effects. RJF led to an increase in the number of neutrophils in peripheral blood, with no significant impact on other hematological indices. In contrast, CTX reduced red blood cell count, hemoglobin levels, and white blood cell count, while increasing platelet count. RJF exhibited no discernible influence on hepatorenal function, whereas Cyclophosphamide (CTX) decreased ALP, GOT, and GPT levels. Both CTX and RJF reduced the expression of Ki67 and heightened the occurrence of apoptosis in tumor tissue. RJF drug-containing serum hindered the viability of 4T1 and MD-MBA-231 cells in a time and concentration-dependent manner. In cell cycle experiments, RJF diminished the proportion of G2 phase cells and arrested the cell cycle at the S phase. RT-PCR analysis indicated that RJF down-regulated the mRNA expression of CDK2 and CDK4, while up-regulating that of P21 and P27 in tumor tissue. The trends in CDKs and CDKIs protein expression mirrored those of mRNA expression. Moreover, the PI3K/AKT pathway displayed downregulation in the tumor tissue of mice treated with RJF.

Targeting multiple immune mechanisms may overcome therapy resistance and further improve cancer immunotherapy for humans. Here, we describe the application of virus-like vesicles (VLV) for delivery of three immunomodulators alone and in combination, as a promising approach for cancer immunotherapy. VLV vectors were designed to deliver single chain interleukin (IL)-12, short-hairpin RNA (shRNA) targeting programmed death ligand 1 (PD-L1), and a dominant-negative form of IL-17 receptor A (dn-IL17RA) as a single payload or as a combination payload. Intralesional delivery of the VLV vector expressing IL-12 alone, as well as the trivalent vector (designated CARG-2020) eradicated large established tumors. However, only CARG-2020 prevented tumor recurrence and provided long-term survival benefit to the tumor-bearing mice, indicating a benefit of the combined immunomodulation. The abscopal effects of CARG-2020 on the non-injected contralateral tumors, as well as protection from the tumor cell re-challenge, suggest immune-mediated mechanism of protection and establishment of immunological memory. Mechanistically, CARG-2020 potently activates Th1 immune mechanisms and inhibits expression of genes related to T cell exhaustion and cancer-promoting inflammation. The ability of CARG-2020 to prevent tumor recurrence and to provide survival benefit makes it a promising candidate for its development for human cancer immunotherapy.

BackgroundInterleukin-17 (IL-17) family cytokines promote protective inflammation for pathogen resistance, but also facilitate autoimmunity and tumor development. A direct signal of IL-17 to regulatory T cells (Tregs) has not been reported and may help explain these dichotomous responses.MethodsWe generated a conditional knockout of Il17ra in Tregs by crossing Foxp3-YFP-Cre mice to Il17ra-flox mice (Il17raΔTreg mice). Subsequently, we adoptively transferred bone marrow cells from Il17raΔTreg mice to a mouse model of sporadic colorectal cancer (Cdx2-Cre+/ApcF/+), to selectively ablate IL-17 direct signaling on Tregs in colorectal cancer. Single cell RNA sequencing and bulk RNA sequencing were performed on purified Tregs from mouse colorectal tumors, and compared to those of human tumor infiltrating Treg cells.ResultsIL-17 Receptor A (IL-17RA) is expressed in Tregs that reside in mouse mesenteric lymph nodes and colon tumors. Ablation of IL-17RA, specifically in Tregs, resulted in increased Th17 cells, and exacerbated tumor development. Mechanistically, tumor-infiltrating Tregs exhibit a unique gene signature that is linked to their activation, maturation, and suppression function, and this signature is in part supported by the direct signaling of IL-17 to Tregs. To study pathways of Treg programming, we found that loss of IL-17RA in tumor Tregs resulted in reduced RNA splicing, and downregulation of several RNA binding proteins that are known to regulate alternative splicing and promote Treg function.ConclusionIL-17 directly signals to Tregs and promotes their maturation and function. This signaling pathway constitutes a negative feedback loop that controls cancer-promoting inflammation in CRC.

Abstract Objective: To study the predictive effect of systemic immune-inflammatory index (SII) on cancer prevalence and mortality. Methods: Participants with SII and cancer status were screened from the National Health and Nutrition Examination Survey database from 1999 to 2010, and their baseline characteristics were analyzed according to the SII tertile. Multivariable logistical or Cox proportional hazards models were used to analyze the associations between SII with cancer prevalence or mortality. The mortality was followed through December 31 2018. For further evaluation on associations of SII with specified outcomes, restricted cubic spline and two piecewise regression models were adopted. Results: This study eventually included 26,049 individuals, of whom 2,432 were cancer patients. According to the SII tertile group, cancer prevalence increased significantly with the rise of SII. In the highest tertile of SII, SII was significantly related to cancer prevalence (OR=1.45, 95%CI= 1.31 - 1.61, p<0.05). Moreover, during a median follow-up of 12.75 year, 329, 351, and 1,202 cardiovascular, cancer and all-cause deaths occurred among cancer patients, respectively. The results indicated that highest level of SII was significantly associated with increased cardiovascular mortality (HR=1.80, 95%CI= 1.28 - 2.52), cancer mortality (HR=1.64, 95%CI= 1.28 - 2.09) and all-cause mortality (HR=1.56, 95%CI= 1.31- 1.85). The model adjusted for multiple covariates still showed the same trend. U-shaped dose-response associations between log-transformed SII (ln-SII) with prevalence and mortality of cancer were detected. The threshold values of ln-SII for the lowest risk associated with cancer prevalence, cardiovascular mortality cancer mortality and all-cause mortality were 5.44, 6.21, 6.27 and 6.21, respectively. Above thresholds, SII was positively associated with increased risk of above outcomes. Conclusion: SII may be a potential earlier warning marker for the prevalence and mortality of total cancers.

BackgroundInterleukin-17 (IL-17) family cytokines play critical roles in inflammation and pathogen resistance. Inflammation in the central nervous system, denoted as neuroinflammation, promotes the onset and progression of Alzheimer's disease (AD). Previous studies showed that IL-17A neutralizing antibody treatment alleviated Amyloid beta (A beta) burden in rodent models of AD, while overexpression of IL-17A in mouse lateral ventricles rescued part of the AD pathology. However, the involvement of IL-17 in AD and its mechanism of action remain largely unknown.MethodsTo investigate the role of IL-17 in AD, we crossed mice lacking the common receptor of IL-17 signaling (IL-17RA knockout mice) to the APP/PS1 mouse model of AD. We then analyzed the composition of immune cells and cytokines/chemokines during different phases of AD pathology, and interrogated the underlying mechanism by which IL-17 may regulate immune cell infiltration into AD brains.ResultsAblation of IL-17RA in APP/PS1 mice decreased infiltration of CD8+ T cells and myeloid cells to mouse brain. IL-17 was able to promote the production of myeloid- and T cell-attracting chemokines CXCL1 and CXCL9/10 in primary glial cells. We also observed that IL-17 is upregulated in the late stage of AD development, and ectopic expression of IL-17 via adenoviral infection to the cortex trended towards worsened cognition in APP/PS1 mice, suggesting a pathogenic role of excessive IL-17 in AD.ConclusionOur data show that IL-17 signaling promotes neuroinflammation in AD by accelerating the infiltration of CD8+ T lymphocytes and Gr1+ CD11b+ myeloid cells.

BackgroundAs increasing experimental evidence suggests that iron metabolism play crucial roles in cancer and non-cancer conditions, there is a lack of data on serum soluble transferrin receptor (sTfR), a promising marker representing unmet cellular iron demands, between cancer risk from epidemiological studies. Here, we aimed to evaluate the predictive value of sTfR and cancer prevalence. Materials and methodsWe analyzed on 5,480 adult participants from 2015 to 2018 National Health and Nutrition Examination Survey (NHANES). Spearman correlation analysis was performed to investigate the correlations between sTfR and other characteristics. To identify the associations between sTfR and the prevalence of cancers, stratified multivariable logistic regression models, subgroup and sensitivity analyses were also performed. ResultsIn tertile analyses, participants in the highest level of sTfR were significantly associated with increased prevalence of total cancers [odds ratio (OR) = 1.53, 95% confidence interval (CI): 1.15-2.02] as compared with those at the lowest tertile. Each unit increment in ln-transformed sTfR concentration was shown to be associated with 39% increased risks of total cancers. Similar associations were found in males rather than females. Further subgroup and sensitivity analyses indicated that, in continuous and tertile analyses, sTfR was more closely associated with male- and female-specific cancers of prostate and testis (2.35: 1.03-5.40; 2.03: 1.00-4.09; respectively), and breast, cervix, ovary and uterus (1.92: 1.11-3.35; 1.66: 1.02-2.69; respectively). ConclusionsOur findings suggested that elevated level of sTfR was associated with the prevalence of cancers, especially in sex-specific cancers. In order to better determine them, further research in humans will be required.

Cystic fibrosis (CF) is an inherited life-threatening disease accompanied by repeated lung infections and multiorgan inflammation that affects tens of thousands of people worldwide. The causative gene, cystic fibrosis transmembrane conductance regulator (CFTR), is mutated in CF patients. CFTR functions in epithelial cells have traditionally been thought to cause the disease symptoms. Recent work has shown an additional defect: monocytes from CF patients show a deficiency in integrin activation and adhesion. Because monocytes play critical roles in controlling infections, defective monocyte function may contribute to CF progression. In this study, we demonstrate that monocytes from CFTRΔF508 mice (CF mice) show defective adhesion under flow. Transplanting CF mice with wild-type (WT) bone marrow after sublethal irradiation replaced most (60-80%) CF monocytes with WT monocytes, significantly improved survival, and reduced inflammation. WT/CF mixed bone marrow chimeras directly demonstrated defective CF monocyte recruitment to the bronchoalveolar lavage and the intestinal lamina propria in vivo. WT mice reconstituted with CF bone marrow also show lethality, suggesting that the CF defect in monocytes is not only necessary but also sufficient to cause disease. We also show that monocyte-specific knockout of CFTR retards weight gains and exacerbates dextran sulfate sodium-induced colitis. Our findings show that providing WT monocytes by bone marrow transfer rescues mortality in CF mice, suggesting that similar approaches may mitigate disease in CF patients.

e14560 Background: Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in humans. Treatment of late-stage CRC remains ineffective, even with the use of latest immunotherapies. Oncolytic viruses have shown limited use for the treatment of cancers, and further improvement of these agents with immune-modulating activities may prove crucial for patients with CRC and other malignancies. To this end, we developed CARG-2020 as an artificial virus for infectious diseases and immuno-oncology (AVIDIO) that employs virus-like vesicles (VLV). VLVs, which are membrane-encapsulated RNA replicons, are oncolytic and can deliver multiple genes resulting in the modulation of several independent immune pathways. Methods: The AVIDIO platform is comprised of in vitro evolved RNA-dependent RNA polymerase from an alphavirus, Semliki Forest virus, and envelope glycoproteins from vesicular stomatitis virus, which together form VLVs. Unarmed or empty vector (VLV), VLV armed with IL-12 (VLV-IL-12) and a VLV that simultaneously expresses IL-12, a dominant-negative form of IL-17 receptor A (dn-1L17RA) and shRNAs targeting PD-L1 (CARG-2020), were given intratumorally to test their therapeutic potential against established (500-600mm 3 ) MC38 tumors in mice. We used tumor growth measurements and analyses of tumor-infiltrating cells after consecutive treatments with these agents to monitor their antitumor and immunomodulatory activities, respectively. Results: Both VLV-IL-12 and CARG-2020 regressed the tumors to undetectable levels in most mice harboring syngeneic MC38 tumors when given intratumorally. CARG-2020, carrying IL-12, dn-IL17RA and PD-L1 shRNA, exerts broader spectrum of immuno-responses and higher number of complete response rates compared with VLV-IL-12. Treatment of primary tumors with VLV-IL-12 or CARG-2020 also significantly repressed the growth of secondary tumors on the other flank of mouse’s body, suggesting an effective systemic immunity elicited by these two agents against the same type of tumors. In addition to the marked local and systemic activation of Th1 cells and CD8 + T cells by both vectors, CARG-2020 also downregulated PD-L1 expression in tumors, and suppressed expression of IL-17A-activated chemokines CXCL1 and CXCL2 that are known to promote cancer development and therapy resistance. Conclusions: As an oncolytic RNA replicon, AVIDIO platform-derived CARG-2020 encodes IL-12, dn-IL-17RA and PD-L1 shRNAs which are expressed concurrently within the same vector. CARG-2020 modulates IL-12, IL-17RA and PD-L1 signaling, and exerts broad immune modulation in tumor microenvironment. Treatment with CARG-2020 eliminates the majority of grafted large tumors in mice, and is effective against both primary and distal tumors. Based on this impressive efficacy results, further development of CARG-2020 in colorectal patients is warranted.

Inflammatory bowel diseases are rising in prevalence globally. While current treatments aim to achieve remission, there remains no cure for this disease. IL-17 family cytokines are important players in inflammation, but clinical trials using anti-IL-17A or IL-17RA blocking antibodies have failed for Crohn’s disease, due to exacerbated inflammation in some patients. While anti-IL-17 antibodies have shown efficacy in the treatment of other autoimmune diseases like psoriasis, patients can often develop Crohn’s disease as a side effect of these drugs. These data suggest a protective role of IL-17 in gut inflammation. The proper activation and function of regulatory T cells is essential for the protection against intestinal autoimmune inflammation. Using the naïve T cell transfer model of colitis in mice, we found that IL-17RA-null iTregs, transferred after the establishment of colitis, were less effective at controlling the colitis compared to WT iTregs. Naïve T cells cultured ex vivo in iTreg polarizing conditions had an increase in complete iTreg differentiation when stimulated with IL-17 cytokines. Our results indicate that IL-17 directly signals to Tregs and assists their anti-inflammatory role during autoimmune gut inflammation. Although the underlying mechanism remains under study, this finding suggests an inhibitory loop between IL-17 and Tregs for the control of overt inflammation.

e15210 Background: Colorectal cancer is the third deadliest of all cancers causing more than 50,000 deaths per year in the U.S. Oncolytic viruses have seen limited use for the treatment of cancers, and further improvement of these methods with immune-modulating activities may prove crucial for the effectiveness of these agents in the treatment of human malignancies. To this end, we developed an artificial virus for infectious diseases and immuno-oncology (AVIDIO) platform that employs virus-like vesicles (VLV) for both the delivery of immunomodulatory agents to tumors and oncolytic activity. Methods: The AVIDIO platform is comprised of in vitro evolved RNA-dependent RNA polymerase from an alphavirus, Semliki forest virus, and envelope glycoproteins from vesicular stomatitis virus, which together form VLVs. Both unarmed VLVs and VLVs armed with the p35 subunit of IL-12 (VLV-IL12p35), an immunomodulatory cytokine that can induce Th1-mediated immunity, were tested for oncolytic activity against various cancer cell lines, including MC38 colorectal cancer cells, in vitro. Using the MC38 syngeneic murine tumor model, we evaluated the antitumor activity of VLV-IL-12p35 in vivo. We used tumor growth measurements and analyses of tumor-infiltrating cells after consecutive treatments with VLV-IL-12p35 to monitor its antitumor and immunomodulatory activities, respectively. Results: VLV-IL-12p35 showed robust oncolytic activity against MC38 cells in vitro, killing over 80% of cells within 24 h. Treatment of intradermal MC38 tumors by intra-tumoral delivery of VLV-IL-12p35 resulted in more than 65% suppression of tumor growth within 2 weeks ( p< 0.05). VLV-IL-12p35-treated tumors also harbored significantly more CD8+ T cells, IFN-gamma-producing CD4+ T cells, and reduced numbers of Foxp3+ regulatory T cells. Conclusions: Our results show that VLV-IL-12p35 derived from the AVIDIO platform has oncolytic activity in vitro and antitumor and immunomodulatory activities in vivo. Therefore, AVIDIO is a promising platform for the delivery of immunomodulatory agents to tumors. Further optimization of the platform, including the addition of other immunomodulatory agents, is in progress to advance the AVIDIO platform to clinical applications for colorectal cancer.

BACKGROUND:The IL-17 family cytokines are potent drivers of colorectal cancer (CRC) development. We and others have shown that IL-17 mainly signals to tumor cells to promote CRC, but the underlying mechanism remains unclear. IL-17 also dampens Th1-armed anti-tumor immunity, in part by attracting myeloid cells to tumor. Whether IL-17 controls the activity of adaptive immune cells in a more direct manner, however, is unknown.METHODS:Using mouse models of sporadic or inducible colorectal cancers, we ablated IL-17RA in the whole body or specifically in colorectal tumor cells. We also performed adoptive bone marrow reconstitution to knockout CXCR3 in hematopoietic cells. Histological and immunological experimental methods were used to reveal the link among IL-17, chemokine production, and CRC development.RESULTS:Loss of IL-17 signaling in mouse CRC resulted in marked increase in the recruitment of CD8+ cytotoxic T lymphocytes (CTLs) and regulatory T cells (Tregs), starting from early stage CRC lesions. This is accompanied by the increased expression of anti-inflammatory cytokines IL-10 and TGF-β. IL-17 signaling also inhibits the production of T cell attracting chemokines CXCL9 and CXCL10 by tumor cells. Conversely, the inability of hematopoietic cells to respond to CXCL9/10 resulted in decreased tumor infiltration by CTLs and Tregs, decreased levels of IL-10 and TGF-β, and increased numbers of tumor lesions. Blockade of IL-17 signaling resulted in increased expression of immune checkpoint markers. On the other hand, treatment of mouse CRC with anti-CTLA-4 antibody led to increased expression of pro-tumor IL-17.CONCLUSION:IL-17 signals to colorectal tumor cells and inhibits their production of CXCL9/10 chemokines. By doing so, IL-17 inhibits the infiltration of CD8+ CTLs and Tregs to CRC, thus promoting CRC development. Cancer immunotherapy may be benefited by the use of anti-IL-17 agents as adjuvant therapies, which serve to block both IL-17-mediated tumor promotion and T cell exclusion.

We described a ribonuclease-dependent cleavable beacon primer, an energy-transfer-tagged oligonucleotide inserted with a ribonucleotide, which can be cleaved by ribonuclease to generate enhanced fluorescence signals and initiate DNA amplification for single nucleotide mutation detection with ultrahigh sensitivity and selectivity.

Chronic inflammation is linked to the development of multiple cancers, including those of the colon. Inflammation in the gut induces carcinogenic mutagenesis and promotes colorectal cancer initiation. Additionally, myeloid and lymphoid cells infiltrate established tumors and propagate so called “tumor-elicited inflammation”, which in turn favors cancer development by supporting the survival and proliferation of cancer cells. In addition to the interaction between cancer cells and tumor infiltrating immune cells, the gut also hosts trillions of bacteria and other microbes, whose roles in colorectal inflammation and cancer have only been appreciated in the past decade or so. Commensal and pathobiotic bacteria promote colorectal cancer development by exploiting tumor surface barrier defects following cancer initiation, by invading normal colonic tissue and inducing local inflammation, and by generating genotoxicity against colonic epithelial cells to accelerate their oncogenic transformation. On the other hand, a balanced population of microbiota is important for the prevention of colorectal cancer due to their roles in providing certain bacterial metabolites and inhibiting intestinal inflammation. In this review we summarize our current knowledge regarding the link between microbiota, inflammation, and colorectal cancer, and aim to delineate the mechanisms by which gut microbiome and inflammatory cytokines regulate colorectal tumorigenesis.