FAP-α Gene Editing    

Fibroblast activation protein-α (FAP-α) is a serine protease composed of 760 amino acids. As one of the members of the type II protease family, it has the activities of dipeptidyl peptidase and collagenase, as well as certain non-enzymatic activities. Fap-α-α is only expressed in tumor-associated fibroblasts (CAFs), but not in fibroblasts of normal tissues. As one of the tumor-specific markers, Fap-α plays an important role in promoting the occurrence, invasion and metastasis of tumors. Tumor cells can be altered at the genetic level to highly express Fap-α, which further promotes tumor growth, metastasis and infiltration. At the same time, Fap-α is used as a target, which provides a new direction for tumor treatment.

Physiological Function

Fap-α has the same protease hydrolysis effect as dipeptidyl peptidase IV and can degrade dipeptides. However, the protease hydrolysis characteristics of Fap-α have positional characteristics, which are more prone to cleavage of the carboxyl terminus by proline residues. Fap-α also has collagenase activity and can degrade gelatin and type I collagen. Besides, Fap-α can hydrolyze the cell-matrix by dipeptidyl peptidase and collagenase, change the tumor microenvironment, and make tumor cells spread and metastasize. In addition, Fap-α can increase the adhesion of macrophages by lysing type I collagen in the surrounding matrix. This effect in tumor tissues may accumulate more cells to perform phagocytosis and promote tumor immune escape. Fap-α is mostly expressed in cancer cells and tumor-related fibroblasts and affects the secretion of protein and other cytokines by fibroblasts. However, Fap is also found in non-tumor-related diseases (rheumatoid arthritis, liver cirrhosis, obesity, diabetes, etc.) -α expression, and in healthy people, Fap-α is mainly expressed in bed healing and scar tissue.

Fap-α Affects Tumor Signal Transduction Pathway and Immune Regulation

The non-enzymatic activity of Fap-α can mediate signal transduction through different signal pathways and affect the occurrence and development of tumors. In lung squamous cell carcinoma, Fap-α can reduce the expression of E-cadherin and β-catenin through the sonic hedgehog pathway, promote epithelial-part-time transformation, and cause tumor metastasis and invasion. Expression of Fap-α in osteosarcoma tissue activates the P13K pathway and further activates the AKT pathway (Fap-α can also directly act on the ERK pathway without passing through the PI3K pathway). The phosphorylation of the AKT/ERK pathway promotes the expression of endothelial growth factor A, to provide a way for tumor growth and metastasis. In gastric adenocarcinoma cells, Fap-α promotes the proliferation, migration, invasion and apoptosis of gastric adenocarcinoma cells through the Wnt/β-catenin pathway. The cure rate of malignant tumors is low, and the mortality rate is high. In the process of tumor development, it depends to a certain extent on the failure of the body's immune response to tumors and the immune escape of tumor cells. Immune regulation, especially the loss or suppression of T cell immunity, plays a huge role in tumor development and metastasis. Fap-α can induce senescence of T cells, which makes its immune function to tumor tissues invalid. In TME, osteosarcoma mesenchymal stem cells expressing Fap-α can activate the downstream AKT pathway through the PI3K pathway. On the one hand, it reduces the expression of cytokine CD28 and serum anti-telomerase reverse transcriptase (nTERT) to make T cells age. Play immunosuppression, on the other hand, express TGF-β and IL-6 cytokines, further release cytokines or chemokines through direct contact or indirect action, activate Th17 cells to express transcription factor RORγ and cytokine IL-17, and induce T Cell senescence.

Fig 1. FAP-α affects tumor signal transduction pathway and immune regulation mechanism

FAP-α and Tumor Targeted Therapy

FAP-α has dipeptidyl peptidase and collagenase activities, can cleavage substrates of many dipeptidyl peptidase activities including gelatin and denatured type I collagen in the matrix, participate in ECM degradation, and promote tumor cells from primary Site detachment, invasion and metastasis, so selective inhibition of Fap-α enzyme activity will help to weaken the invasion and metastasis ability of tumor cells. Val-boroPro (Talabostat) is an enzyme activity inhibitor obtained by the boronic acid reaction with Fap-α specific dipeptide substrate Val-Pro. It can effectively inhibit the activity of peripheral blood Fap-α enzyme and can be used for colorectal cancer. In addition, some Fap-α vaccines can also be used for tumor treatment. Experiments have shown that after inoculation with Fap-α DNA vaccine, it can significantly inhibit the growth of primary tumors in mice through CD8+T cell-mediated killing and prolong the lifespan of mice.

FAP-α Gene Editing Service

CRISPR/Cas9 Platform^CB, one of the leading biotechnological companies specializing in gene editing, is dedicated to offering comprehensive CRISPR/Cas9 gene-editing services to a wide range of genomics researchers. Based on our platform, we can help you effectively FAP-α gene deleted, inserted or point mutated in cells or animals by CRISPR/Cas9 technology.

• FAP-α Gene Knockout: We offer FAP-α gene knockout cell line and knockout animal model generation service with high quality. Typically, we develop CRISPR-mediated gene editing cell lines including HEK239T, Hela, HepG2, U87, but we can use other cell lines according to your requirements. Our one-stop KO animal model generation service that covers from sgRNA design and construct, pronuclear microinjection to Founders genotyping and breeding.
• FAP-α Gene Knockin: CRISPR/Cas9 Platform^CB provides the one-stop FAP-α knock-in cell line and knockout animal model generation services, including point mutation and gene insertion. Our expert staff has succeeded in dozens of FAP-α knock-in cell line generation projects, including stem cells, tumor cells and even difficult-to-handle cells. We also have extensive experience in incorporating CRISPR/Cas9 technology into animal models, which have been fully recognized by our clients.

If you have any questions, please feel free to contact us.

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