Mouse Model Of Colorectal Cancer Research Articles

Broad-spectrum efficacy of CEACAM6-targeted antibody-drug conjugate with BET protein degrader in colorectal, lung, and breast cancer mouse models.

Despite remarkable advances in cancer treatment, most solid cancers remain difficult to cure. We recently developed an antibody-drug conjugate (ADC, 84-EBET) for pancreatic cancer by using the carcinoembryonic-antigen-related cell-adhesion molecule 6 (CEACAM6) antibody #84.7 and the bromodomain and extra-terminal (BET) protein degrader EBET. Here, we showed the overexpression of CEACAM6 in colorectal, lung, and breast cancers (CRC, LC, BC) and the broad-spectrum efficacy of 84-EBET in mouse models of these cancers. In vitro assays using cancer organoids and cell lines of CRC, LC, and BC revealed that 84-EBET was more potent than ADCs with known approved payloads-DXd, SN38, and monomethyl auristatin E (MMAE)-or standard chemotherapies. In mouse studies, a single injection of 84-EBET induced marked regression of CRC-, LC-, and BC-patient-derived xenograft tumors and cell-line-derived xenograft tumors. Moreover, in mouse syngeneic CRC, LC, and BC models resistant to PD-1 antibody, the combination of 84-EBET and PD-1 antibody induced complete regression of most tumors. Mechanistically, 84-EBET degraded BRD4 protein in both cancer and stromal cells via bystander efficacy. It decreased stromal inflammatory phenotypes and increased activated T-cell numbers in tumors. These results demonstrate that delivering BET protein degraders to tumors and their microenvironments via a CEACAM6-targeted ADC may be effective against a wide range of solid cancers.

Fusobacterium nucleatum promotes colorectal cancer through neogenesis of tumor stem cells.

Intestinal stem cells are crucial for maintaining intestinal homeostasis, yet their transformation into tumor stem cells in the context of microbial infection remains poorly understood. Fusobacterium nucleatum is frequently associated with the onset and progression of colorectal cancer (CRC). In this study, we uncovered that F. nucleatum colonized the depths of gut crypts in both patients with CRC and mouse models. Through single-cell sequencing analysis, we demonstrated that F. nucleatum infection reprogrammed crypt cells and activated lymphocyte antigen 6 complex, locus A+ ( LY6A+, also known as stem cell antigen 1 [Sca-1]) revival stem cells (RSCs), promoting their hyperproliferation and subsequent transformation into tumor stem cells, which accelerated intestinal carcinogenesis. Mechanistically, we identified LY6A as a glycosylphosphatidylinositol-anchored (GPI-anchored) membrane receptor for F. nucleatum. Upon binding, F. nucleatum induced the upregulation of ribosomal protein S14 (RPS14) via the LY6A receptor, driving RSC hyperactivity and tumorigenic conversion. Functional studies showed that genetic ablation of Ly6a in intestinal epithelial cells or Rps14 in LY6A+ RSCs substantially reduced F. nucleatum colonization and tumorigenesis. Moreover, analysis of clinical CRC cohorts revealed a strong correlation between F. nucleatum infection, RSC expansion, and elevated RPS14 expression in tumor tissues. These findings highlight an alternative F. nucleatum/LY6A/RPS14 signaling axis as a critical driver of CRC progression and propose potential therapeutic targets for effective CRC intervention.

Design, synthesis and biological evaluation of novel β-carbolines as antitumor agents via targeting autophagy in colorectal cancer

A series of novel β-carbolines with a flexible amino side chain at positions 1 and 3, respectively, were designed, synthesized and evaluated as potential antitumor agents. The results revealed that most of the compounds exhibited a broad spectrum of antiproliferative activity with IC50 value lower than 20μM against human tumor cell lines. Among them, compound 2f was the most potent antiproliferative agent with IC50 value below 5.0μM against human tumor cell lines. Subsequent studies on the in vivo antitumor efficacy of the representative compound 2f demonstrated its ability to hinder tumor progression and significantly diminish tumor mass in a mouse model of colorectal cancer. Further investigation on mechanisms of action showed that compound 2f induced autophagy via the ATG5/ATG7 pathway in HCT116cells. These compounds may contribute to the development of therapeutic agents for colorectal cancer.

Diet therapy abates mutant APC and KRas effects by reshaping plasma membrane cholesterol nanodomains.

Cholesterol-enriched plasma membrane domains are known to serve as signaling platforms in a diverse array of cellular processes. However, the link between cholesterol homeostasis and mutant APC-KRas-associated colorectal tumorigenesis remains to be established. Thus, we investigated the impact of Apc-Kras on 1) colonocyte plasma membrane cholesterol homeostasis, order, and receptor nanoclustering, 2) colonocyte cell proliferation, and 3) whether these effects are modulated by select membrane active dietaries (MADs). We observed that oncogenic APC-KRas increased membrane order by perturbing cholesterol homeostasis when cell proliferation is upregulated, in part by altering the expression of genes associated with cholesterol influx, export and de novo synthesis in mouse colorectal cancer (CRC) models and CRC patients. In addition, oncogene-induced loss of cholesterol homeostasis altered Fzd7, LRP6, and KRas cluster structure/organization. Notably, we show that the combination of chemoprotective MADs, i.e., n-3 PUFAs and curcumin, reduced colonic membrane free cholesterol, order, receptor cluster size, cell proliferation, and the number of dysplastic foci in mutant APC-KRas models. This work highlights the dynamic shaping of plasma membrane organization during colon tumorigenesis and the utility of membrane-targeted cancer therapy.

Fasting-mimicking diet-enriched Bifidobacterium pseudolongum suppresses colorectal cancer by inducing memory CD8+ T cells

BackgroundFasting-mimicking diet (FMD) boosts the antitumour immune response in patients with colorectal cancer (CRC). The gut microbiota is a key host immunity regulator, affecting physiological homeostasis and disease pathogenesis.ObjectiveWe aimed...

Transplantation of the MSLN-deficient Thymus Generates MSLN Epitope Reactive T Cells to Attenuate Tumor Progression.

The development of mesothelin (MSLN) epitope reactive T cells is observed in mice that are immunized with the MSLN vaccine. Engineered T cells expressing MSLN-reactive high-affinity TCR exhibit extraordinary therapeutic effects for invasive pancreatic ductal adenocarcinoma in a mouse model. However, the generation of MSLN-reactive T cells through the introduction of MSLN-deficient thymus and the transplantation of the latter as a cure for cancer treatment have not been tested to date. In the present study, the expression of MSLN was mainly identified in medullary thymic epithelial cells (mTECs) but not in hematopoietic cells, cortical thymic epithelial cells (cTECs), endothelial cells, or fibroblast cells in the thymus. The increasement of activated T cells was observed in MSLN-expressing tumors from MSLN-deficient mice, indicating that MSLN-reactive T cells had developed. Finally, in an AOM-DSS-induced mouse model of colorectal cancer (CRC), transplantation of MSLN-deficient thymus repressed the progression of CRC, accompanied by an increased number of IFNγ-expressing T lymphocytes in the tumors. The data from this study demonstrated that ectopic transplantation of MSLN-deficient thymus induced MSLN-specific antitumor responses to MSLN-expressing tumors, and thus attenuated tumor progression.

First-in-class ultralong-target-residence-time p38α inhibitors as a mitosis-targeted therapy for colorectal cancer.

Colorectal cancer (CRC) constitutes the second leading cause of cancer-related death worldwide and advanced CRCs are resistant to targeted therapies, chemotherapies and immunotherapies. p38α (Mapk14) has been suggested as a therapeutic target in CRC; however, available p38α inhibitors only allow for insufficient target inhibition. Here we describe a unique class of p38α inhibitors with ultralong target residence times (designated ULTR-p38i) that robustly inhibit p38α downstream signaling and induce distinct biological phenotypes. ULTR-p38i monotherapy triggers an uncontrolled mitotic entry by activating Cdc25 and simultaneously blocking Wee1. Consequently, CRC cells undergo mitotic catastrophe, resulting in apoptosis or senescence. ULTR-p38i exhibit high selectivity, good pharmaco-kinetic properties and no measurable toxicity with strong therapeutic effects in patient-derived CRC organoids and syngeneic CRC mouse models. Conceptually, our study suggests ultralong-target-residence-time kinase inhibitors as an alternative to covalent inhibitors, which, because of the lack of cysteine residues, cannot be generated for many kinase cancer targets.

Integration of Metabolomics and Transcriptomics to Reveal the Antitumor Mechanism of Dendrobium officinale Polysaccharide-Based Nanocarriers in Enhancing Photodynamic Immunotherapy in Colorectal Cancer.

Background: The mechanism of Dendrobium officinale polysaccharide-based nanocarriers in enhancing photodynamic immunotherapy in colorectal cancer (CRC) remains poorly understood. Methods: The effects of TPA-3BCP-loaded cholesteryl hemisuccinate-Dendrobium officinale polysaccharide nanoparticles (DOP@3BCP NPs) and their potential molecular mechanism of action in a tumor-bearing mouse model of CRC were investigated using non-targeted metabolomics and transcriptomics. Meanwhile, a histopathological analysis (H&E staining, Ki67 staining, and TUNEL assay) and a qRT-PCR analysis revealed the antitumor effects of DOP@3BCP NPs with and without light activation. Results: Through metabolomics and transcriptomics analysis, we found an alteration in the metabolome and functional pathways in the examined tumor tissues. The metabolic analysis showed 69 and 60 differentially expressed metabolites (DEMs) in positive- and negative-ion modes, respectively, in the treated samples compared to the Control samples. The transcriptomics analysis showed that 1352 genes were differentially expressed among the three groups. The differentially regulated functional pathways were primally related to the antitumor immune response. The results of the pathological histology assay and qRT-PCR analysis verified the findings of the integrated metabolomics and transcriptomics analysis. Conclusions: Overall, our findings elucidate the potential antitumor mechanisms of the D. officinale polysaccharide-based nanocarrier in enhancing photodynamic immunotherapy in CRC.

Artificial metalloenzyme assembly in cellular compartments for enhanced catalysis.

Artificial metalloenzymes (ArMs) integrated within whole cells have emerged as promising catalysts; however, their sensitivity to metal centers remains a systematic challenge, resulting in diminished activity and turnover. Here we address this issue by inducing in cellulo liquid-liquid phase separation through a self-labeling fusion protein, HaloTag-SNAPTag. This strategy creates membraneless, isolated liquid condensates within Escherichia coli as protective compartments for the assembly of ArMs using the same fusion protein. The approach allows for high ArM loading and stabilization by localizing the ArMs within the phase-separated regions. Consequently, the performance of ArM-based whole-cell catalysts is improved, with a demonstrated turnover per cell of up to 7.1 × 109 for the olefin metathesis reaction. Furthermore, we apply this to an engineered E. coli system in live mice, where host bacterial cells confine the metal catalytic species, and in a mouse colorectal cancer model, where ArM-containing whole-cell catalysts mediate concurrent reactions to activate prodrugs.

LBP-CD155 Liposome Nanovaccine Efficiently Resist Colorectal Cancer and Enhance ICB Therapy.

Colorectal cancer (CRC) is a highly malignant and aggressive gastrointestinal tumor. Due to its weak immunogenicity and limited immune, cell infiltration lead to ineffective clinical outcomes. Therefore, to improve the current prophylaxis and treatment scheme, offering a favorable strategy efficient against CRC is urgently needed. Here, we developed a nanovaccine (LBP-CD155L NVs) loaded with CD155 gene in liposome, which was modified by Lycium barbarum polysaccharides (LBP) through electrostatic interaction. The nanovaccine was characterized by transmission electron microscopy and Zetasizer. It was evaluated in vitro, where NVs facilitated the endocytosis and maturation of DCs, and in vivo, where NVs improved the efficacy of prophylaxis and therapy. In addition, further confirmed the mechanisms by how TLR4 and MGL synergistic pathway endow the nanovaccines towards dendritic cells (DCs). Finally, the safety and tumor immunosuppressive microenvironment were evaluated in the CRC tumor-bearing mouse model. We successfully developed a nanovaccine that facilitates the endocytosis and maturation of DCs via a synergistic pathway involving TLR4 and MGL, which endow the nanovaccines towards dendritic cells (DCs) and promote the differentiation, thereby enhancing the cytotoxicity of CD8+T cells. Consequently, LBP-CD155L NVs can potentiate the efficacy of prophylactic and therapeutic administration in a mouse CRC model, as evidenced by decreased infiltration of myeloid-derived suppressor cells (MDSCs) and Tregs, reprogrammed the macrophage phenotypes, which promoted polarization from M2-like macrophages to M1-like macrophages, increased infiltration of effector T cells. Prophylactic and therapeutic combination regimens with anti-PD-1 treatment demonstrate synergism that stimulates T-cell infiltration into tumors and counteracts immunosuppression, leading to remarkable tumor remission and enhancing the efficacy of immune checkpoint therapy in solid tumors. Our work provided that LBP-CD155L NVs may serve as a promising tool for reversing tumor immunosuppressive microenvironment and enhancing ICB therapy in CRC.

A STING agonist prodrug reprograms tumor-associated macrophage to boost colorectal cancer immunotherapy.

Rationale: Tumor-associated macrophages (TAMs) are abundant in colorectal cancer (CRC), correlating with immunosuppression and disease progression. Activation of the stimulator of interferon gene (STING) signaling pathway in TAMs offers a promising approach for CRC therapy. However, current STING agonists face challenges related to tumor specificity and administration routes. Method: The Cancer Genome Atlas (TCGA) database analysis and multicolor immunofluorescence experiments of human CRC samples analysed triggering receptor expressed on myeloid cells 2 (TREM2) expression in the tumor microenvironment of CRC patients. We designed and synthesized a STING agonist prodrug GB2 to reprogram TAMs by targeting TREM2 in tumors. Preliminary evaluation of the anti-tumor capacity of prodrug GB2 in the mouse CRC model intravenously. RNA-seq analysis of bone marrow-derived macrophages (BMDM) after GB2 treatment reveals novel pharmacological mechanisms for the prodrug GB2. Results: Over-expressed TREM2 in TAMs correlates with CRC progression. Via targeting TREM2 expressed in TAMs, GB2 induces comprehensive tumor regression by administrating intravenously in mouse colon cancer models, as well as in a STINGlow mouse melanoma model, with no systemic toxicity. Upon treatment with GB2, TAMs exhibit an M1 phenotype with pro-inflammatory function and demonstrate enhanced phagocytosis capacity. The molecular mechanisms involve (1) GB2 upregulating the Glycolysis-ROS-HIF-1α axis, thereby promoting glucose metabolism and inflammatory cytokine expression; (2) GB2 inducing endoplasmic reticulum-mitochondria contact (MERC), leading to mitochondrial fission, ultimately facilitating Ca2+-mediated phagocytosis. Besides, GB2-treated macrophages reverse immunosuppression, facilitating CD8+ T cell tumor infiltration and effector function. Combining GB2 with αPD-1 therapy reveals a synergistic effect on tumor inhibition, leading to prolonged mouse survival. Conclusion: By targeting TREM2 and activating the STING signaling pathway in TAMs, prodrug GB2 exhibits excellent anti-tumor efficacy and immune-activating capacity in the mouse colon cancer model.

Molecular Mechanisms of Synergistic Effect of PRIMA-1met and Oxaliplatin in Colorectal Cancer With Different p53 Status.

The toxicity and drug resistance associated with oxaliplatin (L-OHP) limit its long-term use for colorectal cancer (CRC) patients. p53 mutation is a common genetic trait of CRC. PRIMA-1met (APR-246, eprenetapopt) restores the DNA-binding capacity of different mutant P53 proteins. PRIMA-1met has progressed to the Phase III clinical trial. Our study explores the combination therapy of PRIMA-1met and L-OHP for CRC with different p53 status. Cell viability was assessed with Cell Counting Kit-8 (CCK-8) assay and combination index (CI) was calculated using The Chou-Talalay method. We also employed wound healing assay and colony formation assay to determine the effect of L-OHP, PRIMA-1met and their combination. Weighted gene co-expression network analysis (WGCNA) of RNA-seq data was conducted to identify key modules and central genes related to different treatment modalities. Xenograft CRC mouse model was used to assess the combination treatment invivo. Our findings showed heightened cytotoxicity and inhibition of migration, and colony formation in CRC cells treated with both drugs, irrespective of p53 status, presenting a promising avenue for addressing L-OHP resistance and toxicity. RNA-seq analysis revealed differential responses between p53-wide type HCT116 and p53-mutant DLD-1 cells, with pathway alterations implicated in tumorigenesis. WGCNA identified key modules and hub genes associated with combination therapy response. Invivo studies demonstrated enhanced efficacy of combined therapy over PRIMA-1met alone, while mitigating L-OHP-induced toxicity. In summary, our research reveals the differential molecular mechanisms of combined PRIMA-1met and L-OHP in CRC with wild type p53 and mutant p53. Our data not only demonstrate that this combined regimen exerts synergistic anti-CRC effect invitro and invivo, but also suggest the benefit of PRIMA-1met on prevention of L-OHP-related side effects. These findings underscore the clinical potential of PRIMA-1met-L-OHP combination therapy in CRC, offering enhanced efficacy and reduced toxicity, warranting further clinical investigation.

Antitumor Activity and Immunostimulant Properties of Liposomes Containing Rosemary Extract on a Mouse Model of Colorectal Cancer.

Rosemary (Ros) is a member of the Lamiaceae family known for its antitumor properties. However, its low water solubility and impaired bioavailability are limiting factors when using rosemary extract. Liposomes are synthetic vesicles that offer permeability, improved bioavailability, and lack of immunogenicity and toxicity, making them ideal for delivering various drugs. To prepare liposomes (HSPC/Chol/mPEG2000-DSPE) containing rosemary alcoholic extract (LipRos) and evaluate its antitumor properties in a mouse model of colorectal cancer (CRC). LipRos were prepared and characterized. CRC was induced in Balb/c mice by subcutaneous injection of C26 cells, and tumor size was monitored continuously. The MTT assay was performed to evaluate cytotoxicity, and liver and kidney function tests were conducted to assess safety. The expression of the pro-apoptotic gene B-cell-lymphoma-2 (Bcl-2), the anti-apoptotic gene Bcl-2-associated-X-protein (Bax), and the expression of cytokines Tumor-necrosis-factor-alpha (TNF-α), Transforming-growth-factor-beta (TGF-β), and Interferon-gamma (IFN-γ) were investigated using real-time PCR. Flow cytometry was used to evaluate the count of cytotoxic (CTL) and regulatory T lymphocytes (Tregs) in spleen and tumor tissue. The results showed that the size of liposomal formulations and their encapsulation efficiency were 113.4 nm and 85%, respectively. The MTT assay demonstrated insignificant cytotoxicity of LipRos on splenocytes, and the tumor size was significantly reduced in the LipRos group (P=0.00045). LipRos also significantly decreased Bcl-2 gene expression (P=0.0086), increased Bax and IFN-γ gene expression (P=0.031), and enhanced the infiltration of CTLs in tumor tissue (P=0.023). This study showed that PEGylated (Poly-Ethylene-Glycol) liposomes containing rosemary extract exhibit an antitumor effect on C26 colorectal cancer cells through multiple mechanisms. These findings can be utilized in future studies.

Gegen Qinlian Decoction Attenuates Colitis-Associated Colorectal Cancer via Suppressing TLR4 Signaling Pathway Based on Network Pharmacology and In Vivo/In Vitro Experimental Validation.

Background: Gegen Qinlian Decoction (GQD), is used for intestinal disorders like ulcerative colitis, irritable bowel syndrome, and colorectal cancer. But the precise mechanisms underlying its anti-inflammatory and anti-tumor effects are not fully elucidated. Methods: Use network pharmacology to identify targets and pathways of GQD. In vivo (azoxymethane/dextran sodium sulfate (AOM/DSS)-induced colitis-associated colorectal cancer (CAC) mouse model) and in vitro (lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages) experiments were conducted to explore GQD's anti-inflammatory and anti-tumor effects. We monitored mouse body weight and disease activity index (DAI), and evaluated colon cancer tissues using hematoxylin and eosin staining. Expression of Ki67 and F4/80 was determined by immunohistochemistry analysis. The protein levels of TLR4 signaling pathway were assessed by western blotting analysis. Enzyme-linked immunosorbent assay measured IL-1β, IL-6, and TNF-α levels. Immunofluorescence (IF) staining visualized NF-κB and IRF3 translocation. Results: There were 18, 9, 24 and 77 active ingredients in the four herbs of GQD, respectively, targeting 435, 156, 485 and 691 genes. Through data platform analysis, it was concluded that there were 1104 target genes of GQD and 2022 target genes of CAC. Moreover, there were 99 intersecting genes between GQD and CAC. The core targets of GQD contained NFKB1, IL1B, IL6, TLR4, and TNF, and GQD reduced inflammation by inhibiting the TLR4 signaling pathway. In vivo experiment, GQD increased mouse body weight, lowered DAI scores, while also alleviating histopathological changes in the colon and decreasing the expressions of Ki67 and F4/80 in the AOM/DSS-induced mice. GQD reduced IL-1β, IL-6, and TNF-α levels in the serum and downregulated TLR4, MyD88, and phosphorylation of IκBα, P65, and IRF3 in the colon tissue from AOM/DSS-induced mice. In vitro, GQD suppressed pro-inflammatory cytokines and TLR4 signaling pathway in the LPS-induced RAW264.7 cells, and combined with TAK242, it further reduced the phosphorylation of IκBα, P65. Conclusions: GQD mitigated CAC by inhibiting the TLR4 signaling pathway, offering a potential therapeutic approach for CAC management.

Chang-Wei-Qing Combined with PD-1 Inhibitor Alleviates Colitis-Associated Colorectal Tumorigenesis by Modulating the Gut Microbiota and Restoring Intestinal Barrier

Chang-Wei-Qing (CWQ) is a widely recognized Traditional Chinese Medicine (TCM) formulation composed of Astragalus, Codonopsis, Atractylodes, Poria, Coix seed, Akebia trifoliata Koidz, Sargentodoxa cuneata, and Vitis quinquangularis Rehd. This formulation has garnered significant interest for its positive effects in mitigating colorectal cancer, and when combined with PD-1, it affects some gut microbiota associated with tumor infiltrating lymphocytes cells. However, the biological rationale underlying the suppression of colitis-associated colorectal cancer (CAC) in AOM/DSS-treated mice by CWQ combined with PD-1 inhibitor remains to be explored. Our aim is to explore the chemopreventive effect of CWQ combined with PD-1 inhibitor on CAC, with a focus on modulating the gut microbiota. A mouse model of CAC was established using azoxymethane (AOM) and dextran sulfate sodium (DSS) treatment. Pathological evaluation of tissue samples included immunohistochemistry and hematoxylin and eosin staining. Intestinal barrier function was assessed by transmission electron microscopy. Fecal microbiota and metabolites were analyzed through 16 S rRNA gene sequencing and liquid chromatography-mass spectrometry, respectively. Mice treated with antibiotics served as models for fecal microbiota transplantation. CWQ combined with PD-1 inhibitor suppressed CAC in AOM/DSS-treated mice. This combined therapy effectively alleviated gut dysbiosis in the CAC model by increasing microbial diversity, enriching probiotic populations such as Limosilactobacillus and Bifidobacterium, and reducing pathogenic bacteria like Desulfovibrio. Additionally, CWQ combined with PD-1 inhibitor downregulated metabolites associated with the NF-kappa B signaling pathway. The combined treatment also significantly improved intestinal barrier function in CAC mice. Transmission electron microscopy of the CWQ combined with PD-1 inhibitor group showed enhanced cellular integrity, a relatively normal mitochondrial structure with intact membranes, and a more abundant, unexpanded endoplasmic reticulum, underscoring the protective effects of this combination on intestinal barrier integrity. Transcriptomic analysis further demonstrated that the combined therapy upregulated genes involved in tight and adherens junctions, while downregulating genes linked to innate immune responses. CWQ combined with PD-1 inhibitor can ameliorate dysbiosis in the AOM/DSS mouse model, with the metabolites of the gut microbiome potentially possessing anti-inflammatory activity. Moreover, CWQ combined with PD-1 inhibitor improves intestinal barrier function, thereby effectively inhibiting the occurrence and development of CAC.

A Pan-RAS Inhibitor with a Unique Mechanism of Action Blocks Tumor Growth and Induces Antitumor Immunity in Gastrointestinal Cancer.

RAS is a common driver of cancer that was considered undruggable for decades. Recent advances have enabled the development of RAS inhibitors, but the efficacy of these inhibitors remains limited by resistance. Here, we developed a pan-RAS inhibitor, ADT-007, that binds nucleotide-free RAS to block GTP activation of effector interactions and MAPK/AKT signaling, resulting in mitotic arrest and apoptosis. ADT-007 potently inhibited the growth of RAS mutant cancer cells irrespective of the RAS mutation or isozyme, and RASWT cancer cells with GTP-activated RAS from upstream mutations were equally sensitive. Conversely, RASWT cancer cells harboring downstream BRAF mutations and normal cells were essentially insensitive to ADT-007. Sensitivity of cancer cells to ADT-007 required activated RAS and dependence on RAS for proliferation, while insensitivity was attributed to metabolic deactivation by UDP-glucuronosyltransferases that were expressed in RASWT and normal cells but repressed in RAS mutant cancer cells. ADT-007 displayed unique advantages over KRAS mutant-specific, pan-KRAS, and pan-RAS inhibitors that could impact in vivo antitumor efficacy by escaping compensatory mechanisms that lead to resistance. Local administration of ADT-007 showed robust antitumor activity in syngeneic immune-competent and xenogeneic immune-deficient mouse models of colorectal and pancreatic cancer. The antitumor activity of ADT-007 was associated with the suppression of MAPK signaling and activation of innate and adaptive immunity in the tumor immune microenvironment. Oral administration of ADT-007 prodrug also inhibited tumor growth. Thus, ADT-007 has the potential to address the complex RAS mutational landscape of many human cancers and to improve treatment of RAS-driven tumors.

Gut virome dysbiosis impairs antitumor immunity and reduces 5-fluorouracil treatment efficacy for colorectal cancer.

Despite the established influence of gut bacteria, the role of the gut virome in modulating colorectal cancer (CRC) patient chemotherapy response remains poorly understood. In this study, we investigated the impact of antiviral (AV) drug-induced gut virome dysbiosis on the efficacy of 5-FU in CRC treatment. Using a subcutaneous CRC mouse model, we assessed tumor growth and immune responses following AV treatment, fecal microbiota transplantation (FMT), and 5-FU administration. AV therapy reduced the abundance of gut DNA and RNA viruses, leading to accelerated tumor growth, shortened survival, and diminished chemotherapy efficacy. FMT restored the gut virome, improving tumor suppression and extending the survival of 5-FU-treated mice. Metagenomic sequencing revealed significant changes in virome composition, AV treatment expanded Kahnovirus, Petivirales, and Enterogokushovirus, whereas FMT enriched Peduovirus STYP1, Mahlunavirus rarus, and Jouyvirus ev207. AV treatment reduced the number of dendritic cells and CD8+ T cells in peripheral blood and tumor tissues, impairing antitumor immunity, FMT reversed these deficiencies. To further investigate the underlying mechanisms, we examined the TLR3-IRF3-IFN-β pathway, essential for recognizing viral RNA and triggering immune responses. AV treatment downregulated this pathway, impairing immune cell recruitment and reducing chemotherapy efficacy, while activation of TLR3 with Poly(I:C) restored pathway function and enhanced the effectiveness of 5-FU. These findings suggest the importance of maintaining gut virome integrity or activating TLR3 as adjunct strategies to enhance chemotherapy outcomes in CRC patients.

Targeting the SIRT3/MnSOD and JNK/HMGB1/Beclin 1 Axes: Role of Apigenin in Multifaceted Metabolic Intervention in Colorectal Cancer.

Colorectal cancer (CRC) is the third most prevalent cancer worldwide. While chemotherapy remains the standard treatment approach, natural products have emerged as a promising alternative. Among these, apigenin, a natural flavonoid, has garnered significant attention due to its pro-oxidant and antioxidant properties in various types of cancer. This study aimed to assess the potential impact of apigenin in CRC treatment by targeting mitochondrial SIRT3, HMGB1, and beclin 1-mediated autophagy in a mouse model of CRC. We administered 20 mg/kg of dimethyl hydrazine (DMH) intraperitoneally once weekly for 20 weeks to induce CRC in C57BL/6 mice. After 6 weeks of initiating the study, apigenin was intragastrically co-administered by oral gavage at 25 and 50 mg/kg until the end of week 20. The results revealed significant weight loss, shortening of the colon, and diarrhea in DMH-induced CRC, which are considered the marks of CRC. In addition, histopathological examination revealed dysplastic changes in the DMH-treated group, while no dysplasia was found in the apigenin-treated CRC groups. Importantly, the administration of apigenin to DMH-treated animals has led to a significant reduction of SIRT3 and MnSOD expression levels with a significant increase in LC3-II at either dose and a significant dose-dependent increase in the levels of MDA, c-JNK, HMGB1, and beclin 1 compared to the DMH-treated group. In conclusion, apigenin may have a promising role in suppressing DMH-induced CRC. It elicits a pro-oxidant activity by suppressing the gene expression of SIRT3 and subsequently, its target MnSOD, resulting in increased reactive oxygen species (ROS) and lipid peroxidation. The released ROS, in turn, activates JNK-mediated autophagy by enhancing HMGB1, beclin 1, and LC3-II protein levels.

A Phosphatidyl Conjugated Telomerase-Dependent Telomere-Targeting Nucleoside Demonstrates Colorectal Cancer Direct Killing and Immune Signaling.

Telomerase and telomeres are crucial in cancer cell immortalization, making them key targets for anticancer therapies. Currently, 6-thio-dG (THIO) combined with the anti-PD-1 inhibitor Cemiplimab is under phase II clinical investigation (NCT05208944) in NSCLC patients resistant to prior immunotherapies. This study presents the design, synthesis, and evaluation of novel bimodular conjugate molecules combining telomere-targeting nucleoside analogs and phosphatidyl diglyceride groups. Among them, dihexanoyl-phosphatidyl-THIO (diC6-THIO) showed high anticancer activity with sub-µM EC50 values in vitro across various cancer cell lines. In mouse colorectal cancer models, diC6-THIO demonstrated strong anticancer effects alone and in combination with PD1/PD-L1 inhibitors. Administration of this compound resulted in the efficient formation of Telomere dysfunction Induced Foci (TIFs) in vitro, indicating an on-target, telomerase-mediated telomere-modifying mechanism of action for the molecule. Systemic treatment also activated CD4+ and CD8+ T cells while reducing regulatory T cells, indicating immune system enhancement. Notably, diC6-THIO exhibits an improved solubility profile while maintaining comparable anticancer properties, further supporting its potential as a promising therapeutic candidate. These findings highlight diC6-THIO as a promising telomere-targeting prodrug with dual effects on telomere modification and immune activation.

CHD1L Inhibitor OTI-611 Synergizes with Chemotherapy to Enhance Antitumor Efficacy and Prolong Survival in Colorectal Cancer Mouse Models.

Colorectal cancer (CRC) is one of the most prevalent and deadly forms of cancer. It is universally treated with a combination of the DNA damaging chemotherapy drugs irinotecan, 5-Fluorouracil (5-FU), and oxaliplatin. CHD1L is a novel oncogene that plays critical roles in chromatin remodeling and DNA damage repair, as well as the regulation of malignant gene expression. We show that an inhibitor of CHD1L, OTI-611, when combined with chemotherapy significantly increases DNA damage in CRC cell lines. OTI-611 also synergizes with SN-38, 5-FU, and oxaliplatin in killing CRC tumor organoids. We also demonstrate that, as in breast cancer, OTI-611 traps CHD1L, PARP1, and PARP2 onto chromatin. The entrapment of CHD1L causes the deprotection of PAR chains in the nucleus, ultimately resulting in cell death by CHD1Li-mediated PARthanatos, as measured by AIF translocation to the nucleus. Finally, the combination of low doses of OTI-611 with irinotecan significantly reduces tumor volume and extends survival in CRC xenograft mouse models compared to irinotecan alone. The combination of standard of care chemotherapy drugs with CHD1Li represents a promising advancement in future therapeutic strategies for CRC and other cancers driven by CHD1L.