Human Colorectal Tumors Research Articles

Novel multivalent S100A8 inhibitory peptides attenuate tumor progression and metastasis by inhibiting the TLR4-dependent pathway

The tumor-elicited inflammation is closely related to tumor microenvironment during tumor progression. S100A8, an endogenous ligand of Toll-like receptor 4 (TLR4), is known as a key molecule in the tumor microenvironment and premetastatic niche formation. We firstly generated a novel multivalent S100A8 competitive inhibitory peptide (divalent peptide3A5) against TLR4/MD-2, using the alanine scanning. Divalent peptide3A5 suppressed S100A8-mediated interleukin-8 and vascular endothelial growth factor production in human colorectal tumor SW480 cells. Using SW480-transplanted xenograft models, divalent peptide3A5 suppressed tumor progression in a dose-dependent manner. We demonstrated that combination therapy with divalent peptide3A5 and bevacizumab synergistically suppressed tumor growth in SW480 xenograft models. Using syngeneic mouse models, we found that divalent peptide3A5 improved the efficacy of anti-programmed death (PD)1 antibody, and lung metastasis. In addition, by using multivalent peptide library screening based on peptide3A5, we then isolated two more candidates; divalent ILVIK, and tetravalent ILVIK. Of note, multivalent ILVIK, but not monovalent ILVIK showed competitive inhibitory activity against TLR4/MD-2 complex, and anti-tumoral activity in SW480 xenograft models. As most tumor cells including SW480 cells also express TLR4, S100A8 inhibitory peptides would target both the tumor microenvironment and tumor cells. Thus, multivalent S100A8 inhibitory peptides would provide new pharmaceutical options for aggressive cancers.

Immune escape of colorectal tumours via local LRH-1/Cyp11b1-mediated synthesis of immunosuppressive glucocorticoids.

Control of tumour development and growth by the immune system critically defines patient fate and survival. What regulates the escape of colorectal tumours from destruction by the immune system remains currently unclear. Here, we investigated the role of intestinal synthesis of glucocorticoids in the tumour development during an inflammation-induced mouse model of colorectal cancer. We demonstrate that the local synthesis of immunoregulatory glucocorticoids has dual roles in the regulation of intestinal inflammation and tumour development. In the inflammation phase, LRH-1/Nr5A2-regulated and Cyp11b1-mediated intestinal glucocorticoid synthesis prevents tumour development and growth. In established tumours, however, tumour-autonomous Cyp11b1-mediated glucocorticoid synthesis suppresses anti-tumour immune responses and promotes immune escape. Transplantation of glucocorticoid synthesis-proficient colorectal tumour organoids into immunocompetent recipient mice resulted in rapid tumour growth, whereas transplantation of Cyp11b1-deleted and glucocorticoid synthesis-deficient tumour organoids was characterized by reduced tumour growth and increased immune cell infiltration. In human colorectal tumours, high expression of steroidogenic enzymes correlated with the expression of other immune checkpoints and suppressive cytokines, and negatively correlated with overall patients' survival. Thus, LRH-1-regulated tumour-specific glucocorticoid synthesis contributes to tumour immune escape and represents a novel potential therapeutic target.

Sodium Butyrate Induces CRC Cell Ferroptosis via the CD44/SLC7A11 Pathway and Exhibits a Synergistic Therapeutic Effect with Erastin.

Human normal intestinal epithelial cell line FHT and colorectal tumor cell line HCT-116 were treated with NaB alone or in combination with different programmed cell death inhibitors. Cell activity was then assessed with MTT assays and PI staining; ferroptosis with Fe2+, glutathione (GSH), and lipid peroxidation assays; signaling pathway screening with PCR arrays; and CD44, SCL7A11, and GPX4 expression with Western blotting. A CD44-overexpressing HCT-116 cell line was constructed to determine the effect of the overexpression of CD44 on NaB-induced ferroptosis. The synergistic effect of co-treatment with NaB and Erastin was assessed by isobolographic analysis. NaB induced apoptosis and ferroptosis in HCT-116 cells but only induced low-level apoptosis in FHC cells. Moreover, NaB significantly increased intracellular Fe2+ and promoted GSH depletion and lipid peroxidation in HCT-116 cells. Ferroptosis-related qPCR array analysis identified CD44/SLC7A11 as a potential effector molecular of NaB-induced ferroptosis. NaB significantly inhibited the expression of CD44 and SLC7A11 in mouse CRC tissues. A CD44 overexpressed HCT-116 cell line was used to verify that CD44/SLC7A11 was a key signaling pathway that NaB-induced GSH depletion, lipid peroxidation accumulation, and ferroptosis in HCT-116 cells. Examination of whether NaB can increase the effect of ferroptosis agents showed that NaB, in combination with Erastin, a ferroptosis inducer, further promoted HCT-116 cell death and increased changes of ferroptosis markers. Our results suggest that NaB induces ferroptosis in CRC cells through the CD44/SLC7A11 signaling pathway and has synergistic effects with Erastin. These results may provide new insights into CRC prevention and the combined use of NaB and ferroptosis-inducing agents.

Identifying Colorectal Tumor For Single Cell RNA Sequence Using Rectified Linear Unit With Stochastic Gradient Descent

To detect cell clusters in whole human colorectal tumor cells, mechanisms based on single-cell RNA sequencing have been reported. To address such issues, a deep learning technique for single-cell analysis was recently developed, with promising results. Single- cell RNA sequence data contains detailed information about the transcriptome profile. Through gene expression, this information is presented in the form of patterns. The neural network is shown here to help understand these data representatives. Then we use the differential expression to identify distinct cell types and gene markers. Finally, the proposed identifying colorectal tumor for single-cell RNA sequencing that Rectified Linear Unit (ReLu) with Stochastic Gradient Descent(SGD) is compared to other recently developed models such as ReLu with Adam, ReLu with Limited-BFGS-B, TanH with Adam, TanH with SGD, TanH with Limited-BFGS-B, Sigmoid with Adam, Sigmoid with SGD, Sigmoid with Limited-BFGS-B, Linear with Adam, Linear with Limited-BFGS-B and Linear with SGD. At the moment, the results from identifying colorectal tumor for single-cell RNA sequencing that ReLu with SGD performs better than other recently developed models.

Cedrol, a Sesquiterpene Isolated from Juniperus chinensis, Inhibits Human Colorectal Tumor Growth associated through Downregulation of Minichromosome Maintenance Proteins.

Cedrol, a sesquiterpene alcohol, isolated from Juniperus chinensis has been reported to inhibit minichromosome maintenance (MCM) proteins as cancer biomarkers in human lung cancer in vitro. In the present study, we investigated the anti-cancer activity of cedrol in vitro and in vivo using human colorectal cancer HT29 cells and a human colorectal tumor xenograft model. Cedrol inhibited MCM protein expression and cell growth in HT29 cells, which are associated with G1 arrest and the induction of apoptosis. We demonstrated that cedrol effectively reduced HT29 tumor growth without apparent weight loss in a human tumor xenograft model. Compared with vehicle- and adriamycin-treated tumor tissues, cedrol induced changes in the tumor tissue structure, resulting in a reduced cell density within the tumor parenchyma and reduced vascularization. Moreover, the expression of MCM7, an important subunit of MCM helicase, was significantly suppressed by cedrol in tumor tissue. Collectively, these results suggest that cedrol may act as a potential anti-cancer agent for colorectal cancer by inhibiting MCM protein expression and tumor growth.

Dendritic cell-targeting chemokines inhibit colorectal cancer progression.

Recent progress in cancer immunotherapy has shown its promise and prompted researchers to develop novel therapeutic strategies. Dendritic cells (DCs) are professional antigen-presenting cells crucial for initiating adaptive anti-tumor immunity, therefore a promising target for cancer treatment. Here, anti-tumor activities of DC-targeting chemokines were explored in murine colorectal tumor models. The correlation of chemokine messenger RNA (mRNA) expression with DC markers was analyzed using The Cancer Genome Atlas (TCGA) dataset. Murine colorectal tumor cell lines (CT26 and MC38) stably overexpressing mouse C-C motif chemokine ligand 3 (CCL3), CCL19, CCL21, and X-C motif chemokine ligand 1 (XCL1) were established by lentiviral transduction. The effect of chemokines on tumor cell proliferation/survival was evaluated in vitro by cell counting kit-8 (CCK-8) assay and colony formation assay. Syngeneic subcutaneous tumor models were used to study the effects of these chemokines on tumor growth. Ki-67 expression in tumors was examined by immunohistochemistry. Immune cells in the tumor microenvironment (TME) and lymph nodes were analyzed by flow cytometry. Expression of the four chemokines was positively correlated with the two DC markers [integrin alpha X (ITGAX) and CLEC9A] in human colorectal tumor samples. Tumoral overexpression of DC-targeting chemokines had little or no effect on tumor cell proliferation/survival in vitro while significantly suppressing tumor growth in vivo. Fluorescence-activated cell sorting (FACS) analysis showed that CCL19, CCL21, and XCL1 boosted the ratios of DCs and T cells in CD45+ leukocytes while CCL3 increased the percentage of CD45+ leukocytes in total cells in MC38 tumor. XCL1 had an additional positive effect on antigen uptake by DCs in the TME and antigen transfer to tumor-draining lymph nodes. CCL3, CCL19, CCL21, and XCL1 exhibited potent anti-tumor activities in vivo, although they might differentially regulate immune cells in the TME and antigen transfer to lymph nodes.

Polysaccharide-Peptide from Trametes versicolor: The Potential Medicine for Colorectal Cancer Treatment.

The incidence and mortality of colorectal cancer have shown an upward trend in the past decade. Therefore, the prevention, diagnosis, and treatment of colorectal cancer still need our continuous attention. Finding compounds with strong anticancer activity and low toxicity is a good strategy for colorectal cancer (CRC) therapy. Trametes versicolor is a traditional Chinese medicinal mushroom with a long history of being used to regulate immunity and prevent cancer. Its extractions were demonstrated with strong cell growth inhibitory activity on human colorectal tumor cells, while the anticancer activity of them is not acted through a direct cytotoxic effect. However, the intricacy and high molecular weight make mechanistic research difficult, which restricts their further application as a medication in clinical cancer treatment. Recent research has discovered a small molecule polysaccharide peptide derived from Trametes versicolor that has a distinct structure after decades of Trametes versicolor investigation. Uncertain molecular weight and a complex composition are problems that have been solved through studies on its structure, and it was demonstrated to have strong anti-proliferation activity on colorectal cancer in vitro and in vivo via interaction with EGFR signaling pathway. It opens up new horizons for research in this field, and these low molecular weight polysaccharide peptides provide a new insight of regulation of colorectal cancer proliferation and have great potential as drugs in the treatment of colorectal cancer.

Biodistribution of the photosensitizer temoporfin after in vivo topical application of temoporfin-loaded invasomes in mice bearing subcutaneously implanted HT29 tumor

Temoporfin (mTHPC) has a great potential for the topical photodynamic therapy. However, it presents a highly hydrophobic second generation photosensitizer with low percutaneous penetration. In order to use mTHPC for dermal/transdermal delivery it is necessary to employ some of the penetration enhancement methods. In this study invasomes were used as a highly effective drug nanocarrier system to enhance its skin penetration, being composed of non-hydrogenated soybean lecithin (10% w/v), ethanol (3.3%w/v), a mixture of terpenes (1% w/v of the mixture cineole:citral:d-limonene = 45:45:10 v/v) and phosphate buffer saline up to 100% w/v. A pharmacokinetic/biodistribution study was performed in mice bearing s.c. implanted human colorectal tumor HT29 upon the application of mTHPC-loaded invasomes onto the skin above the underlying tumor. The aim was to obtain the biodistribution profile of mTHPC i.e. to gain data on mTHPC-distribution in the body (tumor, treated skin, muscle, blood, liver and untreated skin) of mice after the topical application of mTHPC-loaded invasomes. The results revealed that a significant mTHPC-amount was found in treated skin already after 2 h of incubation time. As to the tumor, significant amounts were found after 12 h, while the highest mTHPC-amount was found after 24 h. This study showed that invasomes applied onto the skin may deliver mTHPC to the tumor being necessary for PDT. Since mTHPC was also found in blood and liver, transdermal mTHPC delivery was confirmed. In conclusion, mTHPC-invasomes could be used for topical PDT of cutaneous and subcutaneous lesions, however with general photoxicity induced by systemic apsorption of mTHPC lasting only for 2 weeks. Additionally, due to systemic absorption of mTHPC after invasomes application onto the skin, they could be used transdermally for the PDT treatment of diseases, which need systemic drug absorption. However, it should be emphasized that mice were used in the study, differing in the skin properties compared to human skin. Thus, additional studies should be conducted.

Targeting the splicing isoforms of spleen tyrosine kinase affects the viability of colorectal cancer cells

Spleen tyrosine kinase (Syk) expression have been both positively and negatively associated with tumorigenesis. Our goal was to evaluate the contribution of Syk and its two splice variants, full length Syk (L) and short isoform Syk (S), in the tumor biology of colorectal cancer cells (CRC). The analysis of Syk expression in primary human colorectal tumors, as well as the analysis of TCGA database, revealed a high Syk mRNA expression score in colorectal cancer tumors, suggesting a tumor promotor role of Syk in CRC. Our analysis showed that Syk (L) isoform is highly expressed in the majority of the tumor tissues and that it remains expressed in tumors in which global Syk expression is downregulated, suggesting the dependence of tumors to Syk (L) isoform. We also identified a small cluster of tumor tissues, which express a high proportion of Syk (S) isoform. This specific cluster is associated with overexpressed genes related to translation and mitochondria, and down regulated genes implicated in the progression of mitosis. For our functional studies, we used short hairpin RNA tools to target the expression of Syk in CRC cells bearing the activating K-Ras (G13D) mutation. Our results showed that while global Syk knock down increases cell proliferation and cell motility, Syk (L) expression silencing affects the viability and induces the apoptosis of the cells, confirming the dependence of cells on Syk (L) isoform for their survival. Finally, we report the promising potential of compound C-13, an original non-enzymatic inhibitor of Syk isolated in our group. In vitro studies showed that C-13 exerts cytotoxic effects on Syk-positive CRC cells by inhibiting their proliferation and their motility, and by inducing their apoptosis, while Syk-negative cell lines viability was not affected. Moreover, the oral and intraperitoneal administration of C-13 reduced the tumor growth of CRC DLD-1 cells xenografts in Nude mice in vivo.

The neuronal protein Neuroligin 1 promotes colorectal cancer progression by modulating the APC/β-catenin pathway

BackgroundColorectal cancer (CRC) remains largely incurable when diagnosed at the metastatic stage. Despite some advances in precision medicine for this disease in recent years, new molecular targets, as well as prognostic/predictive markers, are highly needed. Neuroligin 1 (NLGN1) is a transmembrane protein that interacts at the synapse with the tumor suppressor adenomatous polyposis Coli (APC), which is heavily involved in the pathogenesis of CRC and is a key player in the WNT/β-catenin pathway.MethodsAfter performing expression studies of NLGN1 on human CRC samples, in this paper we used in vitro and in vivo approaches to study CRC cells extravasation and metastasis formation capabilities. At the molecular level, the functional link between APC and NLGN1 in the cancer context was studied.ResultsHere we show that NLGN1 is expressed in human colorectal tumors, including clusters of aggressive migrating (budding) single tumor cells and vascular emboli. We found that NLGN1 promotes CRC cells crossing of an endothelial monolayer (i.e. Trans-Endothelial Migration or TEM) in vitro, as well as cell extravasation/lung invasion and differential organ metastatization in two mouse models. Mechanistically, NLGN1 promotes APC localization to the cell membrane and co-immunoprecipitates with some isoforms of this protein stimulates β-catenin translocation to the nucleus, upregulates mesenchymal markers and WNT target genes and induces an “EMT phenotype” in CRC cell linesConclusionsIn conclusion, we have uncovered a novel modulator of CRC aggressiveness which impacts on a critical pathogenetic pathway of this disease, and may represent a novel therapeutic target, with the added benefit of carrying over substantial knowledge from the neurobiology field.

Coumarins, furocoumarins and limonoids of Citrus trifoliata and their effects on human colon adenocarcinoma cell lines

Citrus trifoliata L. (Chinese or Japanese bitter orange) is a medicinal plant with furocoumarins and limonoids as characteristic secondary metabolites. The bitter taste of the fruit limits its use as food, however, it is applied in Asian traditional medicine for its antiphlogistic effect, to treat digestive ulcers and different gastrointestinal disorders and cancer. The phytochemical composition and pharmacological characteristics of this species have not been fully discovered, nevertheless its potential antiproliferative or cytotoxic effects might be related to furocoumarins or limonoids.Our aim was to isolate and identify secondary metabolites from C. trifoliata peel and seeds and to investigate their bioactivities that might be related to the supposed anticancer effect of the plant. By using different chromatographic methods, six pure compounds (phellopterin (2), scoparone (3), myrsellin (4), triphasiol (6), umbelliferone (7) and citropten (5,7-dimethoxycoumarin (8)) were isolated from the peel and four (imperatorin (1), auraptene (5), limonin (9) and deacetyl nomilin (10)) from the seeds of C. trifoliata fruits. These compounds are furocoumarin (1, 2), coumarin (3–8), and limonoid derivatives (9, 10). Scoparone (3) has been detected in this species for the first time.The furocoumarins (1–2) showed moderate activity on the human colorectal adenocarcinona tumor cell line COLO 320 in antiproliferative assays and 2 also had remarkable P-glycoprotein inhibitory activity and synergistic effect with doxorubicin. The coumarin 5 showed significant activity on the COLO 320 cell line in antiproliferative assays and P-glycoprotein inhibitory activity in the FACS (fluorescence activated cell sorting) assay.

Tumor-Activatable Nanoparticles Target Low-Density Lipoprotein Receptor to Enhance Drug Delivery and Antitumor Efficacy.

The binding of plasma proteins to nanomedicines is widely considered detrimental to their delivery to tumors. Here, the design of OxPt/SN38 nanoparticle containing a hydrophilic oxaliplatin (OxPt) prodrug in a coordination polymer core and a hydrophobic cholesterol‐conjugated SN38 prodrug on the lipid shell for active tumor targeting is reported. OxPt/SN38 hitchhikes on low‐density lipoprotein (LDL) particles, concentrates in tumors via LDL receptor‐mediated endocytosis, and selectively releases SN38 and OxPt in acidic, esterase‐rich, and reducing tumor microenvironments, leading to 6.0‐ and 4.9‐times higher accumulations in tumors over free drugs. By simultaneously crosslinking DNA and inhibiting topoisomerase I, OxPt/SN38 achieved 92–98% tumor growth inhibition in five colorectal cancer tumor models and prolonged mouse survival by 58–80 days compared to free drug controls in three human colorectal cancer tumor models without causing serious side effects. The study has uncovered a novel nanomedicine strategy to co‐deliver combination chemotherapies to tumors via active targeting of the LDL receptor.

Abstract 6192: ERK/AKT pathways may be the wrong effectors for KRAS signaling inhibition in colorectal cancers

Abstract Colorectal cancer (CRC) is the third highest incident cancer worldwide and a major cause of cancer death. KRAS protein gain-of-function point mutations play major roles in colorectal tumorigenesis. However, direct inhibition of KRAS is challenging as its protein structure is inadmissible to inhibitor docking. Efforts have been diverted to inhibit downstream RAF/MEK/ERK and PI3K/Akt signaling. Nevertheless, none of these inhibitors has progressed to clinical use in CRC despite extensive trials over the past few decades. We examined levels of phospho-ERK1/2(T202/Y204) and phospho-Akt1/2/3(S473) in human colorectal tumor and matched mucosa at least 10 cm away with quantitative near infrared western blot and immunofluorescence imaging. Surprisingly, 75.5% (25/33) of tumors has lower or equivalent phospho-ERK1/2 and 96.9% (31/32) of tumors has lower phospho-AKT1/2/3 compared to matched mucosa, irrespective of KRAS mutation status and tumor stage. In contrast, we discovered KRAS-dependent SOX9 upregulation in 28 of the 31 (90.3%) tumors. CPTAC phosphoproteomics data similarly showed significantly lower phospho-ERK1/2 levels in tumor compared to matched mucosa. Analysis of transcriptome data from TCGA and GEO series GSE95132 also showed no activation of RAF/MEK/ERK signaling in CRC tumors. These data indicate that the pursue of targeted therapy inhibiting RAF/MEK/ERK and PI3K/Akt signaling is unlikely to be effective in sporadic CRC and possibly harmful as phospho-ERK1/2 are highly expressed in the matched mucosa suggesting a role in normal colonic homeostasis. The widespread use of RAF/MEK/ERK or PI3K/Akt signaling downregulation as a biomarker in drug testing on CRC cell lines needs to be re-evaluated. The data suggest further that SOX9 could be an alternative effector and biomarker of KRAS signaling. Citation Format: Peh Yean Cheah, Kuen Kuen Lam, Choong Leong Tang, Emile Tan, Siew Heng Wong. ERK/AKT pathways may be the wrong effectors for KRAS signaling inhibition in colorectal cancers [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 6192.

Abstract 5505: ADAM10-targeting CAR-T cells inhibit colon cancer cell growth in vivo

Abstract Chimeric antigen receptor (CAR) T cell therapy has demonstrated a high degree of efficacy in patients with hematological malignancies such as acute lymphatic leukemia. However, its efficacy in solid tumors remains to be demonstrated. There are a number of issues currently limiting therapeutic treatment of solid tumors with CAR-T cells, none more important than target antigen selection. This is a major challenge in solid tumors due to their heterogenous characteristics and the potential for off-cancer effects. ADAM10, A Disintegrin And Metalloproteinase 10, plays critical roles in a wide range of pathophysiological processes during development and inflammation. These proteolytically active multifunctional proteins act as sheddases by cleaving transmembrane-bound proteins such as growth factors, adhesion molecules and chemokine receptors, which can then contribute to migration and invasion of cancer cells. An active form of ADAM10 that has undergone a conformational change has been identified in several cancer types, particularly colorectal cancer. In this study, a novel CAR was generated based on a previously characterized cancer-specific ADAM10 antibody. ADAM-10-targeting CAR-T cells were manufactured using T cells from the peripheral blood of the healthy donors. The CAR-T cells displayed the naïve and central memory phenotype that has been shown to differentiate and proliferate within tumor microenvironments, with little expression of exhaustion markers. These CAR-T cells were capable of killing several human colorectal tumor cell lines in vitro, assessed in a bioluminescence-based cytotoxicity assay. Furthermore, treatment of NSG mice bearing human LoVo colon cancer cell tumors with ADAM-10-targeting CAR-T cells led to significant inhibition of tumor growth compared with either untransduced control T cells or PBS treatment. Overall, these data suggest that targeting ADAM-10 via CAR-T cell therapy is a promising novel avenue of treatment of colorectal cancer. Citation Format: Elaheh Rohani Rad, Jade Foeng, Dylan McPeak, Timona Tyllis, Caitlin Abbott, Veronika bandara, Silvana Napoli, Batjargal gundsambuu, Simon Barry, Timothy Sadlon, shaun McColl. ADAM10-targeting CAR-T cells inhibit colon cancer cell growth in vivo [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 5505.

Abstract 5574: In vivo characterization of a novel CAR-T cell therapy directed towards LGR5 for the treatment of colorectal cancer

Abstract Colorectal cancer (CRC) is the third most diagnosed cancer and incidence rates are rapidly increasing among young adults. Despite current treatments, the 5-year survival rate is approximately 65%, highlighting an urgent need for new therapies. Leucine-rich repeat-containing G-protein coupled receptor (LGR5) is a promising antigen target for chimeric antigen receptor (CAR)-T cell therapy, which may represent a novel effective treatment for CRC. LGR5 binds R-spondins and functions to enhance Wnt and β-catenin signalling involved in maintenance and proliferation of adult stem cells. Expression of LGR5 has been previously reported on cancer stem cells in CRC, and has been demonstrated to play a crucial role in CRC tumor initiation and metastasis. Flow cytometric analysis of LGR5 cell surface expression on in vitro and ex vivo human CRC tumour cells revealed a subpopulation of LGR5+ cells. Six LGR5-targetting CD3+ CAR-T cell variants were developed, which differed in CAR variable heavy (VH) and variable light (VL) chain orientation and hinge length. As preliminary experimentation identified that four of the six CAR-T cell variants displayed robust anti-tumour cytotoxicity in vitro, these CAR-T cell variants were tested for in vivo anti-tumour efficacy using a subcutaneous human colorectal tumor xenograft mouse model. Pre-injection phenotyping after freeze-thawing of the CAR-T cells revealed greater than 94% transduction efficiency, low expression of co-inhibitory receptors CTLA-4 and PD-1 and a high frequency of central memory T cells (CD62L+ CD45RO+). Additionally, a high frequency of the CD8+ compartment of these CAR-T cells expressed perforin, CD107a, Granzyme B and TNFα. For each variant, intravenous injection of 20x106 LGR5-targeting CAR-T cells induced significant tumor regression and gave 100-day survival post-tumor injection. Ex vivo analyses of tumors and spleens via flow cytometry at endpoint indicated CAR-T cell persistence to 100-days post-tumor injection. Of the CAR-T cells isolated from tumours ex vivo, high level expression of co-inhibitory receptors PD-1, CTLA-4, and TIM-3 was observed. The splenic T cell population was enriched for central memory T cells and expressed high levels of PD-1. Complete tumor remission was achieved in 100% of mice receiving the VH-VL orientation, medium hinge CAR construct (designated CNA3103), prompting further investigation of this variant. Intravenous injection of 5x106 CNA3103 CAR-T cells was sufficient to induce tumour remission and 100-day survival. Similarly, complete tumour rejection was achieved with a dose of 2.5x106 CNA3103 CAR-T cells in a 30-day in vivo experiment. These results demonstrate that LGR5-targeting CAR-T cells exhibit potent in vivo anti-tumor efficacy and position LGR5 as a promising CAR target antigen, prompting investigation of LGR5-targeting CAR-T cells as a therapeutic for CRC in future clinical trials. Citation Format: Dylan J. McPeake, Timona S. Tyllis, Jade Foeng, Veronika Bandara, Caitlin A. Abbott, Batjargal Gundsambuu, Elaheh Rohani-Rad, Silvana Napoli, Timothy Sadlon, Simon C. Barry, Shaun R. McColl. In vivo characterization of a novel CAR-T cell therapy directed towards LGR5 for the treatment of colorectal cancer [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 5574.

Abstract 5575: Pre-clinical validation of a LGR5-targeting CAR-T against colorectal cancer

Abstract Chimeric antigen receptor T cells (CAR-T) have demonstrated robust clinical activity against B-cell malignancies, and rapid translation to approval for use in man has inspired the search for CAR-T cells against solid tumors. Cancer stem cells are a small population of cells within a tumor that have the capacity to self-renew, differentiate, and initiate new tumors. Cancer stem cells are known to be resistant to chemotherapy and radiotherapy and are enriched in residual disease which allows relapse. Targeting cancer stem cells will reduce the tumors’ ability to generate new cells resulting in tumor remission. We have tested a novel CAR-T cell that has the potential to target cancer stem cells. Leucine-rich G protein-coupled receptor 5 (LGR5) expression is restricted to stem cell populations in multiple tissues in adults. In addition, LGR5 is a marker of cancer stem cells and LGR5+ cells are implicated in tumor progression and metastasis. We designed six lentiviral CAR-T constructs targeting the extra cellar domain of LGR5 with differing linker lengths and binding domain orientation, and tested gene delivery to purified human CD3 T cells and in vitro cytotoxicity. All constructs were expressed robustly (>90%), and four of six LGR5-targeting CAR-T cells showed significant antigen-specific cytotoxicity against colorectal cancer cell lines in vitro. We confirmed the on-target specificity of the LGR5 targeting CAR-T using a cell line over-expressing the LGR5 protein and antibody competition assays, which blocked cytotoxicity. Using optimized gene delivery and CAR-T manufacturing protocols, we generated pre-clinical scale batches of the four lead constructs to evaluate their potency in a pre-clinical colorectal cancer xenograft mouse model. Post expansion our cell products expressed markers of self-renewing naïve-like and central memory phenotype and three out of four LGR5-targeting CAR-T cells were able to significantly inhibit the growth of human colorectal tumors. These results suggest a CAR-T targeting LGR5 may provide long-term protection against tumor growth. Our data positions LGR5-targeting CAR-T therapy as a viable therapeutic for human metastatic colorectal cancer types with minimal off-target effects, which we now aim to test in human clinical trials. Citation Format: Veronika Bandara, Stuart Mills, Emma Thompson, Lih Tan, Batjargal Gundsambuu, Silvana Napoli, Jade Foeng, Dylan McPeake, Justin Coombs, Allison Cowin, Claudine Bonder, Timothy Sadlon, Shaun McColl, Simon Barry. Pre-clinical validation of a LGR5-targeting CAR-T against colorectal cancer [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 5575.

P-211 Claudin-16, its clinical and prognostic value in colorectal cancer

Claudin-16, also known as CLDN-16 or paracellin-1, plays a major role in tight junction-specific occlusion of the intercellular space, through calcium-independent cell-adhesion activity, and Involved in paracellular magnesium reabsorption. The CLDN16 gene is a protein coding gene, mutations of which are associated with diseases such as Hypomagnesemia 3, renal and primary hypomagnesemia. Among its related pathways are cell junction organization and Blood-Brain Barrier and immune cell transmigration. Tight junctions represent one mode of cell-to-cell adhesion in epithelial or endothelial cell sheets, forming continuous seals around cells and serving as a physical barrier to prevent solutes and water from passing freely through the paracellular space. Evidence has now identified tight junction as key barriers to metastatic disease and cancer progression. We have previously shown that CL16 is associated with survival in breast cancer. The present study explored the expression and relevance of Claudin-16 in human colorectal cancer. Claudin-16 expression levels in human colorectal tumour and normal tissues were quantitatively analysed using gene transcript analyses. Expression was determined against the clinical and pathological parameters and clinical outcome of the patients including recurrence, metastatic disease and deaths related to colorectal cancer. The Mann Whitney U statistical test was utilised for comparisons and logistic regression, with Kaplan-Meier used for survival analyses. Expression of Claudin-16 was significantly reduced in tumour specimens in this colorectal cohort (p=0.0016, tumour n=83; normal n=41). Paired tumour/normal tissues also indicated a significantly reduces expression in tumour samples (p= 0.0287). There was a progressive reduction in Claudin-16 expression with increasing TNM status (p < 0.08). Intriguingly, expression of Claudin-16 was significantly lower in tumours originating in right colon and the rectum (p < 0.034) and expression was reduced in tumours that were both invasive/non-invasive (p < 0.026). When evaluating disease outcome, patients that remained alive and well had higher levels of Claudin-16 when compared to those with local recurrence, metastatic disease and had dies from cancer (p < 0.0238). Kaplan-Meier curves indicated that Clausin-16 was associated with recurrence of disease and death from colorectal cancer (p < 0.042). Claudin-16 has a highly differential expression in colorectal cancer and exhibits properties that in future may enable its use as a possible prognostic indicator.

LIGHT enhanced bispecific antibody armed T-cells to treat immunotherapy resistant colon cancer

Increased tumor infiltrating lymphocytes (TIL) are associated with improved patient responses to immunotherapy. As a result, there is interest in enhancing lymphocyte trafficking particularly to colon cancers since the majority are checkpoint blockade-resistant and microsatellite stable. Here, we demonstrate that activated T-cells (ATC) armed with anti-CD3 x anti-EGFR bispecific antibody increases TIL and mediate anti-tumor cytotoxicity while decreasing tumor cell viability. Furthermore, treatment induces endogenous anti-tumor immunity that resisted tumor rechallenge and increased memory T-cell subsets in the tumor. When combined with targeted tumor expression of the tumor necrosis factor superfamily member LIGHT, activated T-cell proliferation and infiltration were further enhanced, and human colorectal tumor regressions were observed. Our data indicate that tumor-targeted armed bispecific antibody increases TIL trafficking and is a potentially potent strategy that can be paired with combination immunotherapy to battle microsatellite stable colon cancer.SignificanceEnhancing trafficking of tumor infiltrating lymphocytes (TILs) to solid tumors has been shown to improve outcomes. Unfortunately, few strategies have been successful in the clinical setting for solid tumors, particularly for “cold” microsatellite stable colon cancers. In order to address this gap in knowledge, this study combined TNFSF14/LIGHT immunomodulation with a bispecific antibody armed with activated T-cells targeted to the tumor. This unique T-cell trafficking strategy successfully generated anti-tumor immunity in a microsatellite stable colon cancer model, stimulated T-cell infiltration, and holds promise as a combination immunotherapy for treating advanced and metastatic colorectal cancer.

Pyroptosis-Related Signatures for Predicting Prognosis in Breast Cancer.

BackgroundFemale breast cancer (BC) has become the most common cancer in the world, and its mortality was considerably higher in transitioning vs. transitioned countries. Pyroptosis, an inflammation-dependent programmed cell death mediated by inflammasomes, has been observed in human colorectal tumors and gliomas. However, the characteristics of pyrolysis-related genes and their influence and mechanism on the tumorigenesis and progress of BC were unknown.MethodsBased on the global public database, we used comprehensive bioinformatics analysis to systematically analyze the expression of pyroptosis-related genes in BC and their relationship in tumor progression. In addition, BC patients were divided into two groups, and the clinical features and outcomes could be better predicted by the consistent clustering of pyroptosis-related genes. Least absolute shrinkage and selection operator (LASSO) Cox regression analysis was used to establish a risk score. Then, we further explored the prognostic value and clinical features of pyroptosis genes. Finally, we used the Human Protein Atlas (HPA) platform to identify the expression at protein levels of the key genes.ResultsWe confirmed that the expression of pyroptosis-related genes was different in BC and normal breast tissues. A high frequency of somatic mutations occurred in BC. In addition, 33 pyroptosis-related proteins interacted frequently. Based on univariate analysis and the LASSO Cox model, five pyroptosis-related genes [including GADMA, interleukin-6 (IL-6), NLR pyrin domain-containing protein 6 (NLRP6), caspase-1 (CASP1), and caspase-9 (CASP9)], were obtained to calculate a risk score. The risk score was identified as an independent risk factor for the prognosis of BC and might play an auxiliary role in clinical classification. The HPA platform confirmed that the expression trends of the key genes were consistent with our previous studies.ConclusionPyroptosis had an important effect on the progression of BC. And the pyroptosis-related genes could be used as new prognostic biomarkers and therapeutic targets for BC.

IL-36γ and IL-36Ra Reciprocally Regulate Colon Inflammation and Tumorigenesis by Modulating the Cell-Matrix Adhesion Network and Wnt Signaling.

Inflammatory bowel disease and colorectal cancer are associated with dysregulation of cytokine networks. However, it is challenging to target cytokines for effective intervention because of the overlapping functions and unpredictable interactions of cytokines in such diverse networks. Here, it is shown that IL‐36γ and IL‐36Ra, an agonist and an antagonist for IL‐36R signaling respectively, reciprocally regulate the experimental colitis and the colon cancer development in mice. Knockout or neutralization of IL‐36γ alleviates dextran sulfate sodium (DSS)‐induced colitis and inhibits colon cancer development, whereas knockout of IL‐36Ra exacerbates DSS‐induced colitis and promotes colonic tumorigenesis in multiple colon cancer models in mice. Mechanistically, IL‐36γ upregulates extracellular matrix and cell–matrix adhesion molecules and facilitates Wnt signaling, which is mitigated by IL‐36Ra or IL‐36γ neutralizing antibody. Consistently, IL‐36γ levels are positively correlated with extracellular matrix levels and β‐catenin levels in human colorectal tumor biopsies. These findings suggest the critical role of IL‐36γ and IL‐36Ra in gut inflammation and tumorigenesis and indicate that targeting the IL‐36γ/IL‐36Ra signal balance provides potential therapeutic strategy for inflammatory bowel disease and gastrointestinal cancers.