CXCR4 and colorectal carcinoma: Serum-starved CRC cells (HCT116 and HCT116R) in alginate beads were either left untreated or treated as described in Material and Methods, and as shown in Figure 5, we examined the expression of the NF-κB and NF-κB-regulated gene products that are involved in invasion (MMP-9) and metastasis (CXCR4).