CXCR4 and cancer: To determine whether SDF-1 is a key signaling molecule secreted by INT6-repressed HMFs to influence transforming activities in cancer cells, we added the SDF-1 receptor antagonist AMD3100 and found that HMF-induced colony formation in soft agar was greatly reduced (Figure 3E), with a concurrent reduction of the CAF marker α-SMA (Figure 3F).