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Principal Investigator: Judy Lieberman
Organization: BOSTON CHILDREN'S HOSPITAL
Fiscal Year: 2024
Award: $196,525
Funding agency: National Cancer Institute
Colorectal cancer (CRC) is the third most diagnosed cancer in the US with the second highest mortality rate.
Locally advanced and metastatic disease have a poor prognosis. A small subset (5-15%) of metastatic CRC
patients, who bear tumors deficient in DNA mismatch repair (MMR) that have high microsatellite instability (MSI-
high), can respond to immunotherapy with checkpoint blockade (CPI), but most CRC do not. We hypothesize
that to induce immune responses in microsatellite stable (MSS) CRC, new strategies that go beyond CPI are
needed. In MSI-high CRC tumors, tumor-infiltrating myeloid cells, fibroblasts and the tumors themselves all have
inflammatory gene expression signatures and are colocalized into inflammatory hubs with adjacent tumor-
reactive CD8 T cells, suggesting that MSI-high CRCs selectively provoke a robust inflammatory multicellular
network within the tumor that recruits anti-tumor killer cells. Disruption of MMR in CRC mouse tumor grafts
enhances tumor neoantigen expression and recruitment of tumor-specific T cells to trigger immune surveillance.
We hypothesize that interventions that convert MSS CRC to an MMR-deficient MSI phenotype could enhance
antitumor immunity and make resistant MSS CRC sensitive to CPI. This proposal will investigate whether
tumor-targeted gene knockdown can convert MSS CRC to immune responsive MSI-high tumors. There
are no known small molecule inhibitors of MMR. We will exploit a method of epithelial cancer-targeted gene
knockdown that uses subcutaneous injection of aptamer-small interfering RNAs (AsiCs), which link a high affinity
EpCAM aptamer for epithelial tumor targeting to small interfering RNAs, for tumor-selective gene knockdown.
EpCAM, the first described tumor antigen, is ~100-1000-fold more highly expressed in epithelial cancers
(including virtually all CRC) than normal epithelia, making it attractive for selective CRC tumor targeting. We
previously showed that EpCAM-AsiCs that knockdown tumor-dependency genes or genes whose knockdown
promotes immune recognition can strongly suppress aggressive breast cancer in orthotopic, metastatic and
genetically engineered mouse tumor models and induce an effective immune response in immunologically cold
tumors. In this proposal we will evaluate EpCAM-AsiCs to knockdown Mlh1, encoding a key MMR enzyme, in
MSS CRC subcutaneous and caecal tumor implants of 4 mouse CRC cell lines and 2 MMR-proficient, MSS
organoid lines derived from an aggressive genetically engineered mouse model, which conditionally express
mutations in intestinal stem cells of four key genes that are frequently mutated in human CRC – Apc, Kras,
Tgfbr2 and Trp53. We will evaluate the effect of MMR disruption on tumor growth in immunodeficient and
immunocompetent mice and dissect in detail how microsatellite stability, tumor mutational burden and gene
expression in the tumor and the immune response to the tumor are altered. We will also investigate whether CPI
enhances the antitumor effect of tumor-targeted Mlh1 knockdown.
Terms: <Affinity><Antigen Defined by Monoclonal Antibody AUAI><B-Cell Attracting Chemokine 1><B-Lymphocyte Chemoattractant><BCA1><BLC gene><BLC protein><Blood Neutrophil><Blood Polymorphonuclear Neutrophil><Blood monocyte><Body Tissues><Breast Neoplasms><Breast Tumors><CD8 Cell><CD8 T cells><CD8 lymphocyte><CD8+ T cell><CD8+ T-Lymphocyte><CD8-Positive Lymphocytes><CD8-Positive T-Lymphocytes><CXCL13><CXCL13 gene><Cancers><Carcinogen-DNA Adducts><Carcinoma><Cell Body><Cells><Checkpoint inhibitor><Chemokine, CXC Motif, Ligand 13><Chemotactic Cytokines><Chimera><Chimera organism><Clinical><Colorectal Cancer><Colorectal Neoplasms><Colorectal Tumors><DNA><DNA Adducts><DNA Damage><DNA Injury><Death Rate><Defect><Deoxyribonucleic Acid><Dependence><Disease><Disorder><Drugs><EpCAM><Epithelial Cellular Adhesion Molecule><Epithelial cancer><Epithelium><Expression Signature><Fibroblasts><GA733-2><GEM model><GEMM model><Gastrointestinal Tumor-Associated Antigen 2, 35-KD Glycoprotein><Gene Expression><Gene Expression Profile><Gene Transcription><Genes><Genetic Alteration><Genetic Change><Genetic Transcription><Genetic defect><Genetically Engineered Mouse><Graft Enhancements><HG38><Homologous Chemotactic Cytokines><Human><IFN><Immune><Immune Surveillance><Immune checkpoint inhibitor><Immune mediated therapy><Immune response><Immunes><Immunochemical Immunologic><Immunocompetent><Immunologic><Immunologic Surveillance><Immunologic Surveillances><Immunological><Immunological Surveillance><Immunological Surveillances><Immunological response><Immunologically><Immunologically Directed Therapy><Immunologics><Immunosurveillance><Immunotherapy><Implant><Infiltration><Inflammation><Inflammatory><Intercrines><Interferons><Intervention><Intervention Strategies><Intestinal><Intestines><K Cells><Killer Cells><LGR5><LGR5 gene><Large Bowel Tumor><Large Intestine Neoplasm><Large Intestine Tumor><Link><M4S1><MIC18><MMR deficiency><Macrophage><Malignant Cell><Malignant Epithelial Neoplasms><Malignant Epithelial Tumors><Malignant Neoplasms><Malignant Tumor><Mammary Cancer><Mammary Neoplasms><Marrow Neutrophil><Marrow monocyte><Medication><Membrane Component, Chromosome 4, Surface Marker 1><Metallopeptidases><Metalloproteases><Metalloproteinases><Metastasis><Metastasize><Metastatic Lesion><Metastatic Mass><Metastatic Neoplasm><Metastatic Tumor><Methods><Mice><Mice Mammals><Microsatellite Instability><Microsatellite Markers><Microsatellite Repeats><Microsatellites><Minority><Mismatch Repair><Mismatch Repair Deficiency><Modeling><Modern Man><Murine><Mus><Mutate><Mutation><Myeloid Cells><Mφ><Neoplasm Metastasis><Neutrophil Infiltration><Neutrophil Recruitment><Neutrophilic Granulocyte><Neutrophilic Infiltrate><Neutrophilic Leukocyte><Operative Procedures><Operative Surgical Procedures><Organoids><Outcome><Pharmaceutical Preparations><Phenotype><Polymorphonuclear Cell><Polymorphonuclear Leukocytes><Polymorphonuclear Neutrophils><Post-Replication Mismatch Repair><Progenitor Cells><Prognosis><RNA Expression><Resistance><SCYB13><SIS cytokines><Secondary Neoplasm><Secondary Tumor><Short interfering RNA><Small Inducible Cytokine Subfamily B, Member 13><Small Interfering RNA><Somatic Mutation><Subcutaneous Injections><Surgical><Surgical Interventions><Surgical Procedure><T-Cells><T-Lymphocyte><T8 Cells><T8 Lymphocytes><TACSTD1><TACSTD1 gene><TNBC><Testing><Therapeutic><Tissues><Transcription><Tumor Antigens><Tumor Immunity><Tumor Tissue><Tumor-Associated Antigen><Tumor-Associated Calcium Signal Transducer 1><Tumor-infiltrating immune cells><aggressive breast cancer><anti-tumor effect><anti-tumor immunity><antitumor effect><antitumor immunity><aptamer><bowel><cancer antigens><cancer cell><cancer diagnosis><cancer immunity><cancer infiltrating T cells><cancer metastasis><cancer progenitor><cancer progenitor cells><cancer stem cell><check point blockade><check point immunotherapy><check point inhibitor therapy><check point inhibitory therapy><check point therapy><checkpoint blockade><checkpoint immunotherapy><checkpoint inhibitor therapy><checkpoint inhibitory therapy><checkpoint therapy><chemoattractant cytokine><chemokine><chemotherapy><chimeras><colon cancer cell line><colon cancer patients><colorectal cancer cell line><colorectal cancer patients><colorectal neoplasia><design><designing><drug/agent><epithelial carcinoma><gene expression pattern><gene expression signature><genetically engineered mouse model><genetically engineered murine model><genome mutation><host response><hypoimmunity><immune cell infiltration of tumors><immune cells infiltrating the tumor><immune cells that infiltrate the tumor><immune check point blockade><immune check point inhibitor><immune check point therapy><immune checkpoint blockade><immune checkpoint therapy><immune competent><immune deficiency><immune system response><immune therapeutic approach><immune therapeutic interventions><immune therapeutic regimens><immune therapeutic strategy><immune therapy><immune-based therapies><immune-based treatments><immuno therapy><immunodeficiency><immunoresponse><improved><infiltration of tumors by immune cells><interventional strategy><intratumoral immune cell><intratumoral immune infiltrate><knock-down><knockdown><large bowel neoplasm><malignancy><malignant progenitor><malignant stem cell><mammary tumor><metastatic colo-rectal><metastatic colo-rectal cancer><metastatic colo-rectal carcinoma><metastatic colon cancer><metastatic colorectal><metastatic colorectal cancer><metastatic colorectal carcinoma><monocyte><mortality rate><mortality ratio><neo-antigen><neo-epitopes><neoantigens><neoepitopes><neoplasm/cancer><neutrophil><programs><promoter><promotor><recruit><repair><repair endonuclease><repair enzyme><repaired><resistance mechanism><resistant><resistant mechanism><response><siRNA><small molecular inhibitor><small molecule inhibitor><somatic variant><stem cells><subcutaneous><subdermal><subdermal injection><surgery><thymus derived lymphocyte><transcriptional profile><transcriptional signature><triple-negative breast cancer><triple-negative invasive breast carcinoma><tumor><tumor cell metastasis><tumor growth><tumor immune cell><tumor immune infiltrate><tumor infiltrating T cells><tumor infiltration of immune cells><tumor-specific antigen><virtual>