Panoply™ Human NGF Knockdown Stable Cell Line

Perineural invasion (PNI) and autophagy are two common features of the pancreatic cancer (PanCa) tumor microenvironment, both of which adversely affect prognosis. Here, researchers found that NGF secreted by pancreatic cancer cells activates autophagy in Schwann cells (SCs) during PNI via a paracrine mechanism. Autophagic Schwann cells promote PNI in two ways: a) by enhancing their own migration toward pancreatic cancer cells and their axon-guiding capabilities; and b) by strengthening their chemotactic attraction of pancreatic cancer cells. The NGF-targeting drug RO and the autophagy inhibitor CQ inhibit autophagic flux in Schwann cells and induce their apoptosis. Furthermore, RO and CQ induce apoptosis in pancreatic cancer cells and demonstrate therapeutic efficacy in PNI models. Consequently, therapeutic strategies targeting NGF and autophagy can block neural invasion, offering promising new directions and experimental evidence for the study and treatment of neural invasion in pancreatic cancer.

Here, the researchers generated NGF-knockdown PANC-1 and BxPC-3 cells (Figure 1B and C). To investigate the effect of NGF secreted by pancreatic cancer (PanCa) cells on Schwann cell (SC) autophagy, the researchers co-cultured SCs with normal medium (control group), conditioned medium (CM) from PANC-1 and BxPC-3 cells, or CM from NGF-knockdown PANC-1 and BxPC-3 cells (shNGF-CM). They assessed LC3 and P62 expression via immunofluorescence staining. As shown in Figure 1D, E, and F, CM from PANC-1 and BxPC-3 cells significantly increased the number of LC3 puncta in SCs compared to the control and NGF-knockdown groups. Similarly, CM from PANC-1 and BxPC-3 cells significantly increased the number of P62 puncta compared to the control and NGF-knockdown groups (Figure 1G, H, and I). Furthermore, GFP/RFP dual-labeled LC3 fluorescence assays (Figure 1J and K) revealed that PANC-1 and BxPC-3 CM increased autophagic flux-an effect partially reversed by NGF knockdown-indicating that pancreatic cancer cells promote SC autophagy in an NGF-dependent manner (Figure 1L and M). The researchers also analyzed autophagy-related proteins using Western blotting. As shown in Figure 1N and O, the CM group exhibited higher expression levels of LC3-II, ATG5, and p-ULK1, and lower expression levels of p-mTOR and P62, compared to the control and NGF-knockdown groups. These results indicate that cancer cell-derived NGF partially induces SC autophagy activation, while also suggesting that other factors may be involved in the process of cancer cell-induced SC autophagy.

Figure 1. PanCa-related NGF activates SC autophagy. (Zhang W, et al., 2022)