Overexpression and Role of HHLA2, a Novel Immune Checkpoint, in Colorectal Cancer

• Published in: International journal of molecular sciences Vol. 24; no. 6; p. 5876
• Main Authors: Kula, Agnieszka, Dawidowicz, Miriam, Mielcarska, Sylwia, Kiczmer, Paweł, Skiba, Hanna, Krygier, Małgorzata, Chrabańska, Magdalena, Piecuch, Jerzy, Szrot, Monika, Robotycka, Julia, Ochman, Błażej, Strzałkowska, Bogumiła, Czuba, Zenon, Świętochowska, Elżbieta, Waniczek, Dariusz
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.03.2023; MDPI
• Subjects: Analysis; B cells; Biomarkers, Tumor - genetics; Biomarkers, Tumor - metabolism; Cancer; CD8 antigen; Cell signaling; Chemokines; Colorectal cancer; Colorectal carcinoma; Colorectal Neoplasms - pathology; Cytokines; Cytokines - genetics; Dendritic cells; Eigenvalues; Enzyme-linked immunosorbent assay; Enzymes; Extracellular matrix; Growth factors; Health aspects; HHLA2; Humans; Immune checkpoint; Immune system; Immunoglobulins - metabolism; Immunohistochemistry; Immunotherapy; Lymphocytes; Lymphocytes, Tumor-Infiltrating; Medical research; Medicine, Experimental; Metastases; Microsatellite Instability; MSI; Mutation; Potassium channels (inwardly-rectifying); Principal components analysis; Proteins; Signal transduction; Transforming growth factors; Tumor-infiltrating lymphocytes; Tumors; Poland; California; MSI; colorectal cancer; HHLA2; immune checkpoint; immunotherapy
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms24065876

The study aimed to investigate correlations between HHLA2 levels and parameters, including microsatellite instability (MSI) status, CD8+ cells, and histopathological features: budding, tumor-infiltrating lymphocytes (TILs), TNM scale, grading, cytokines, chemokines, and cell signaling moleculesin colorectal cancer (CRC). Furthermore, the immune infiltration landscape and HHLA2-related pathways in colorectal cancer using available online datasets were analyzed. The study included 167 patients diagnosed with CRC. Expression of HHLA2 was detected by immunohistochemistry method (IHC) and enzyme-linked immunosorbent assay (ELISA). The IHC was used to evaluate the MSI and CD8+ status. The budding and TILs were measured using a light microscope. The concentrations of cytokines, chemokines, and cell signaling molecules were measured to analyze the data by the Bio-Plex Pro Human cytokine screening panel, 48 cytokine assay, and principal component analysis (PCA). Geneset enrichment analysis (GSEA) was conducted to identify HHLA2-related pathways. The biological function of HHLA2 was predicted by Gene Ontology (GO). Analysis of the immune infiltration landscape of HHLA2 in colorectal cancer was made by the web-based tool Camoip. High HHLA2 expression was detected in CRC tumor tissues compared to the adjacent noncancerous tissues. The percentage of HHLA2-positive tumors was 97%. GSEA and GO showed that HHLA2 upregulation correlated with cancer-related pathways and several biological functions. Tumor-infiltrating lymphocytes score correlated positively with IHC HHLA2 expression level percentage. There was a negative correlation between HHLA2, anti-tumor cytokines and pro-tumor growth factors. This study provides a valuable insight into the role of HHLA2 in CRC. We reveal the role of HHLA2 expression as well as a stimulatory and inhibitory immune checkpoint in colorectal cancer. Further research may verify the therapeutic values of the HHLA2-KIR3DL3/TMIGD2 pathway in colorectal cancer.