NK-92MI Cells Engineered with Anti-claudin-6 Chimeric Antigen Receptors in Immunotherapy for Ovarian Cancer.

Background: The application of chimeric antigen receptor (CAR) NK cells in solid tumors is hindered by lack of tumor-specific targets and inefficient CAR-NK cell efficacy. Claudin-6 (CLDN6) has been reported to be overexpressed in ovarian cancer and may be an attractive target for CAR-NK cells immunotherapy. However, the feasibility of using anti-CLDN6 CAR-NK cells to treat ovarian cancer remains to be explored. Methods: CLDN6 expression in primary human ovarian cancer, normal tissues and cell lines were detected by immunohistochemistry and western blot. Two types of third-generation CAR NK-92MI cells targeting CLDN6, CLDN6-CAR1 NK-92MI cells with domains containing self-activated elements (NKG2D, 2B4) and CLDN6-CAR2 NK-92MI cells with classical domains (CD28, 4-1BB) were constructed by lentivirus transfection, sorted by flow cytometry and verified by western blot and qPCR. OVCAR-3, SK-OV-3, A2780, Hey and PC-3 cells expressing the GFP and luciferase genes were transduced. Subcutaneous and intraperitoneal tumor models were established via NSG mice. The ability of CLDN6-CAR NK cells to kill CLDN6-positive ovarian cancer cells were evaluated in vitro and in vivo by live cell imaging and bioluminescence imaging. Results: Both CLDN6-CAR1 and CLDN6-CAR2 NK-92MI cells could specifically killed CLDN6-positive ovarian cancer cells (OVCAR-3, SK-OV-3, A2780 and Hey), rather than CLDN6 negative cell (PC-3), in vitro. CLDN6-CAR1 NK-92MI cells with domains containing self-activated elements (NKG2D, 2B4) exhibited stronger cytotoxicity than CLDN6-CAR2 NK-92MI cells with classical domains (CD28, 4-1BB). Furthermore, CLDN6-CAR1 NK cells could effectively eliminate ovarian cancer cells in subcutaneous and intraperitoneal tumor models. More importantly, CAR-NK cells combined with immune checkpoint inhibitors, anti-PD-L1, could synergistically enhance the antitumor efficacy of CLDN6-targeted CAR-NK cells. Conclusions: These results indicate that CLDN6-CAR NK cells possess strong antitumor activity and represent a promising immunotherapeutic modality for ovarian cancer.

Li J ，Hu H ，Lian H ，Yang S ，Liu M ，He J ，Cao B ，Chen D ，Hu Y ，Zhi C ，Shen Y ，Ye X ，He B ，Zhao M ，Fan W ，Xu L ，Leidner R ，Wu Q ，Yang L ，Zhang Z ... -  《International Journal of Biological Sciences》

Use of chimeric antigen receptor NK-92 cells to target mesothelin in ovarian cancer.

Mesothelin (MSLN) has been reported to be overexpressed in ovarian cancer and may be an ideal target for immunotherapy. Recent studies have suggested that natural killer (NK) cells may be better chimeric antigen receptor (CAR) drivers because of their favorable innate characteristics, such as directly recognizing and killing tumor cells, resulting in a graft-versus-tumor effect but irresponsible for graft-versus-host disease (GVHD). The therapeutic effects of CAR-engineered NK cells targeting MSLN in ovarian cancer have not been evaluated. In this study, MSLN- and CD19-targeted CAR NK-92 (MSLN- and CD19-CAR NK) cells were constructed. Both MSLN- and CD19-CAR molecules were highly expressed on the surface of NK-92 cells following lentiviral gene transduction. MSLN-CAR NK cells specifically killed MSLN-positive ovarian cancer cells (OVCAR-3 and SK-OV-3), rather than MSLN-negative cells (SK-HEP-1), in vitro. Moreover, compared with parental NK-92 cells and CD19-CAR NK cells, stronger cytokine secretion was detected in MSLN-CAR NK cells cocultured with OVCAR-3 and SK-OV-3. Furthermore, MSLN-CAR NK cells effectively eliminated ovarian cancer cells in both subcutaneous and intraperitoneal tumor models; these cells also significantly prolonged the survival of intraperitoneally tumor-bearing mice. These results demonstrate that MSLN-CAR NK cells have robust specific antitumor activity, both in vitro and in vivo, suggesting that mesothelin could be a potential target for CAR NK cells and could be applied in the treatment of ovarian cancer.

Cao B ，Liu M ，Wang L ，Liang B ，Feng Y ，Chen X ，Shi Y ，Zhang J ，Ye X ，Tian Y ，Zhi C ，Li J ，Lian H ，Wu Q ，Zhang Z ... -  《-》

Development of mesothelin-specific CAR NK-92 cells for the treatment of gastric cancer.

Background: The application of chimeric antigen receptor (CAR) NK cells in solid tumors is hindered by lack of tumor-specific targets and inefficient CAR NK cell efficacy. It has been reported that mesothelin (MSLN) may be an ideal immunotherapy target for gastric cancer. However, the feasibility of using anti-MSLN CAR NK cells to treat gastric cancer remains to be studied. Methods: MSLN expression in primary human gastric cancer, normal tissues and cell lines were detected. MSLN and CD19 targeted CAR NK-92 (MSLN- and CD19-CAR NK) cells were constructed, purified and verified. N87, MKN-28, AGS and Huh-7 cells expressing the GFP and luciferase genes were transduced. Cell- and patient-derived xenograft (PDX) were established via NSG mice. The ability of MSLN-CAR NK cells to kill MSLN-positive gastric cancer cells were evaluated in vitro and in vivo. Results: MSLN-CAR NK cells can specifically kill MSLN-positive gastric cancer cells (N87, MKN-28 and AGS), rather than MSLN negative cell (Huh-7), in vitro. Moreover, compared with parental NK-92 cells and CD19-CAR NK cells, stronger cytokine secretions were secreted in MSLN-CAR NK cells cocultured with N87, MKN-28 and AGS. Furthermore, MSLN-CAR NK cells can effectively eliminate gastric cancer cells in both subcutaneous and intraperitoneal tumor models. They could also significantly prolong the survival of intraperitoneally tumor-bearing mice. More importantly, the potent antitumor effect and considerable NK cell infiltration were observed in the patient-derived xenograft treated with MSLN-CAR NK cells, which further warranted the therapeutic effects of MSLN-CAR NK cells to treat gastric cancer. Conclusion: These results demonstrate that MSLN-CAR NK cells possess strong antitumor activity and represent a promising therapeutic approach to gastric cancer.

Cao B ，Liu M ，Huang J ，Zhou J ，Li J ，Lian H ，Huang W ，Guo Y ，Yang S ，Lin L ，Cai M ，Zhi C ，Wu J ，Liang L ，Hu Y ，Hu H ，He J ，Liang B ，Zhao Q ，Zhu K ... -  《International Journal of Biological Sciences》

Anti-αFR CAR-engineered NK-92 Cells Display Potent Cytotoxicity Against αFR-positive Ovarian Cancer.

Ao X ，Yang Y ，Li W ，Tan Y ，Guo W ，Ao L ，He X ，Wu X ，Xia J ，Xu X ，Guo J ... -  《-》

Pharmacologically upregulated carcinoembryonic antigen-expression enhances the cytolytic activity of genetically-modified chimeric antigen receptor NK-92MI against colorectal cancer cells.

Shiozawa M ，Chang CH ，Huang YC ，Chen YC ，Chi MS ，Hao HC ，Chang YC ，Takeda S ，Chi KH ，Wang YS ... -  《BMC IMMUNOLOGY》