Panoply™ Human SLC7A11 Knockdown Stable Cell Line

Cancer-associated fibroblasts (CAFs) play a crucial role in the progression of pancreatic ductal adenocarcinoma (PDAC) through promoting tumor signaling and fibrosis formation, where fibrosis creates a physical barrier that is difficult for drugs to penetrate. Therefore, inhibiting CAFs is an ideal component of PDAC treatment strategies. SLC7A11, a cysteine ​​transporter, has been identified as a potential therapeutic target in PDAC cells. However, previous studies have not evaluated the role of SLC7A11 in the PDAC tumor stroma and its prognostic significance. Here, researchers show that high expression of SLC7A11 in the human PDAC tumor stroma (rather than tumor cells) is an independent predictor of poor prognosis. Orthogonal experiments showed that PDAC-derived CAFs are highly dependent on SLC7A11 for cysteine ​​uptake and glutathione synthesis, and SLC7A11 inhibition significantly reduced CAF proliferation, decreased their antioxidant capacity, and inhibited their ability to remodel collagen and support PDAC cell growth. Importantly, specific knockout of SLC7A11 in tumor compartments of transgenic mouse PDAC tumors did not affect tumor growth, indicating that the matrix can significantly influence the response of PDAC tumors to SLC7A11 inhibition. In mouse orthotopic PDAC models constructed using human PDAC cells and CAFs, stable knockdown of SLC7A11 was required in both cell types to reduce tumor growth, metastasis, and intratumoral fibrosis, demonstrating the importance of targeting SLC7A11 in both compartments.

To determine whether inhibiting SLC7A11 in CAFs affects their ability to support PDAC cell growth, researchers conducted 3D co-culture experiments [spheroid growth assay (Figure 1A) and spheroid growth assay (Figure 1B)]. Transient knockdown of SLC7A11 in CAFs, PDAC cells, or both significantly reduced spheroid growth (Figure 1C). Importantly, knockdown of SLC7A11 alone in CAFs or in both cell types was more effective in inhibiting spheroid growth than knockdown of SLC7A11 alone in PDAC cells (Figure 1C). Similar results were observed in 3D Matrigel-embedded spheroid experiments using a stable knockdown of SLC7A11 in MiaPaCa2 PDAC cells and immortalized CAFs (Figure 1D). Except for knocking down SLC7A11 alone in MiaPaCa-2 PDAC cells, knocking down SLC7A11 alone in CAFs or simultaneously in both PDAC cells and CAFs reduced the size of spheroids at the experimental endpoint (relative to the initial size) by 40% (Figure 1D). Researchers replicated this experiment using the aforementioned SLC7A11 knockdown CAF cell lines in combination with other PDAC cells (Panc-1, AsPC1, TKCC5) and observed a similar reduction in spheroid growth compared to CAF (control-shRNA) spheroids (Figure 1E-G).

Figure 1. SLC7A11 knockdown in CAFs reduced PDAC 3D coculture spheroid growth. (Sharbeen G, et al., 2021)