Programmed cell death ligand 1 disruption by clustered regularly interspaced short palindromic repeats/Cas9‐genome editing promotes antitumor immunity and suppresses ovarian cancer progression

Abstract

Programmed cell death ligand 1 ( PD ‐L1) on tumor cells suppresses anti‐tumor immunity and has an unfavorable prognostic impact in ovarian cancer patients. We herein report the pathophysiological and therapeutic impacts of PD ‐L1 disruption in ovarian cancer. PD ‐L1 was genetically disrupted in the murine ovarian cancer cell line ID 8 using clustered regularly interspaced short palindromic repeats ( CRISPR )/Cas9‐mediated genome editing. PD ‐L1 knockout ( KO ) and control ovarian cancer cells were intraperitoneally inoculated into syngeneic mice, and survival and tumor dissemination were evaluated. Survival times were significantly longer in the PD ‐L1‐ KO ID 8‐inoculated groups than in their control groups, and its therapeutic benefit was enhanced in combination with the cisplatin treatment. Tumor weights and ascites volumes were significantly lower in the PD ‐L1‐ KO ID 8 groups than in their control groups. Immunohistochemical and immunofluorescence analyses showed that intratumoral CD 4 + T cells, CD 8 + T cells, NK cells and CD 11c + M1 macrophages were significantly increased, whereas regulatory T cells were significantly decreased in the PD ‐L1‐ KO ID 8 groups compared with those in their control groups. The intratumoral mRNA expression of interferon‐γ, tumor‐necrosis factor‐α, interleukin ( IL )‐2, IL ‐12a, CXCL 9 and CXCL 10 was significantly stronger, while that of IL ‐10, vascular endothelial growth factor, CXCL 1 and CXCL 2 was significantly weaker in the PD ‐L1‐ KO ID 8 groups. These results indicate that CRISPR /Cas9‐mediated PD ‐L1 disruption on tumor cells promotes anti‐tumor immunity by increasing tumor‐infiltrating lymphocytes and modulating cytokine/chemokine profiles within the tumor microenvironment, thereby suppressing ovarian cancer progression. These results suggest that PD ‐L1‐targeted therapy by genome editing may be a novel therapeutic strategy for ovarian cancer.

Biomarkers of immunotherapy in non‑small cell lung cancer (Review)

“…PD-L1 is a ligand of PD-1 that is highly expressed in various tumor cells, such as lung cancer, malignant brain tumor and melanoma cells (28). The upregulation of PD-1 ligands in the tumor microenvironment and the connection of PD-1 to its ligands on tumor-specific T cells are the key mechanisms of escaping immune elimination (27)(28)(29)(30)(31)(32). For example, PD-1 expressed on CD4 + and CD8 + T cells, as well as other immune cells, interacts with PD-L1.…”

“…For example, PD-1 expressed on CD4 + and CD8 + T cells, as well as other immune cells, interacts with PD-L1. This leads to decreased activation, proliferation, survival, persistence and effector functions of T lymphocytes, induces antigen-specific T cell apoptosis and modulates the activity of CD4 + and CD8 + T cells, NK cells and macrophages, thereby affecting cancer progression in vitro and in vivo ( 29 – 31 ). PD-L1 can be recognized by T cells, resulting in the release of cytokines, which not only attract other cytotoxic immune cells, but can also induce the expression of the checkpoints that promote immune resistance, including the metabolic reprogramming, differentiation characteristics and promotion of homeostatic proliferation of T cells ( 32 – 34 ).…”

Applications of CRISPR‐Cas9 in gynecological cancer research

“…Proto‐oncogenes include EGFR, BRCA1‐/‐2, KRAS, PIK3CA, NOB1p , and other tumor suppressor genes, such as PTEN, TP53, P16 , and WWOX . Aiming at the pathogenesis of ovarian cancer, scientists have achieved significant breakthroughs in suppressing tumor growth by knocking out ovarian cancer oncogenes using CRISPR‐Cas9 technology (summarized in Table ).…”

“…Knock out of BRCA1 in the mouse ovarian carcinoma cell line, ID8, enhances the sensitivity of cancer cells to cisplatin and PARP inhibitors . Similarly, the knockout of PD‐L1 in the mouse ovarian carcinoma cell line, ID8, significantly increased the number of immune cells in the tumors of mouse peritoneal diffusion models, including CD4 + T cells, CD8 + T cells, and CD49 + NK cells, thereby inhibiting the progress of intraperitoneal tumors . In addition to being able to knockout oncogenes, the CRISPR‐Cas9 technology can edit other forms of genes.…”

The diagnostic value of color Doppler ultrasound on ovarian cancer in nude mice

“…Ovarian cancer is one of the most common malignancies of the gynecological system and the mortality of it was highest among all gynecologic ones [1,2]. It is the leading cause of death from gynecological diseases among women worldwide [3,4], and it poses a serious threat to women's health [5].…”