There is great interest in tumor stem cells (TSCs) as potential therapeutic targets; however, cancer therapies targeting TSCs are limited. A drawback is that TSC markers are often shared by normal stem cells (NSCs); thus, therapies that target these markers may cause severe injury to normal tissues. To identify a potential TSC-specific marker, we focused on doublecortin-like kinase 1 (Dclk1). Dclk1 was reported as a candidate NSC marker in the gut, but recent reports have implicated it as a marker of differentiated cells (for example, Tuft cells). Using lineage-tracing experiments, we show here that Dclk1 does not mark NSCs in the intestine but instead marks TSCs that continuously produce tumor progeny in the polyps of Apc(Min/+) mice. Specific ablation of Dclk1-positive TSCs resulted in a marked regression of polyps without apparent damage to the normal intestine. Our data suggest the potential for developing a therapy for colorectal cancer based on targeting Dclk1-positive TSCs.

Chemokines and their receptors play key roles in leukocyte trafficking and are also implicated in cancer metastasis to specific organs. Here we show that mouse B16F10 melanoma cells constitutively express chemokine receptor CXCR3, and that its ligands CXCL9/Mig, CXCL10/IP-10, and CXCL11/I-TAC induce cellular responses in vitro, such as actin polymerization, migration, invasion, and cell survival. To determine whether CXCR3 could play a role in metastasis to lymph nodes (LNs), we constructed B16F10 cells with reduced CXCR3 expression by antisense RNA and investigated their metastatic activities after s.c. inoculations to syngeneic hosts, C57BL/6 mice. The metastatic frequency of these cells to LNs was markedly reduced to ϳ15% (P < 0.05) compared with the parental or empty vector-transduced cells. On the other hand, pretreatment of mice with complete Freund's adjuvant increased the levels of CXCL9 and CXCL10 in the draining LNs, which caused 2.5-3.0-fold increase (P < 0.05) in the metastatic frequency of B16F10 cells to the nodes with much larger foci. Importantly, such a stimulation of metastasis was largely suppressed when CXCR3 expression in B16F10 cells was reduced by antisense RNA or when mice were treated with specific antibodies against CXCL9 and CXCL10. We also demonstrate that CXCR3 is expressed on several human melanoma cell lines as well as primary human melanoma tissues (5 of 9 samples tested). These results suggest that CXCR3 inhibitors may be promising therapeutic agents for treatment of LN metastasis, including that of melanoma.

Colorectal cancer (CRC) is one of the most common causes of cancer deaths worldwide and the number of CRC patients is increasing progressively. Despite the improvement of the surgical techniques and chemotherapy, we have not completely overcome this disease yet due to the metastases. Therefore, understanding the mechanisms through which metastasis occurs is important for overcoming CRC. Normal host cells in the tumor microenvironment, such as macrophages and fibroblasts, have been reported to promote the growth of CRCs. Although neutrophils were originally considered to have defensive functions against tumor cells, it has been revealed that some populations of neutrophils, called as tumor-associated neutrophils (TANs), have tumor-supportive functions. The plasticity between tumor-suppressive and -supportive neutrophils are regulated by transforming growth factor (TGF)-β and Interferon-β signaling. Some studies have demonstrated that TANs promote the spread of cancer cells to distant organs. TANs contribute to the tumor invasion and angiogenesis through the production of matrix metalloproteinase-9 (MMP9), vascular endothelial growth factor (VEGF), and hepatocyte growth factor (HGF) in the primary and metastatic sites. Neutrophils also promotes tumor cell dissemination by capturing circulating tumor cells using neutrophil extracellular traps and promote their migration to distant sites. The neutrophil-to-lymphocyte ratio is a well-defined predictive marker for CRC patients. In this review, we highlight the molecular signaling between TANs and CRC cells and the possibility of TANs as a potential target for cancer therapy.

Various N-sulfonylamino acid derivatives were synthesized and evaluated for their in vitro and in vivo activities to inhibit type IV collagenase (MMP-9 and MMP-2). When the amino acid residue and the sulfonamide moiety were modified, their inhibitory activities were greatly affected by the structure of the sulfonamide moiety. A series of aryl sulfonamide derivatives containing biaryl, tetrazole, amide, and triple bond were found to be potent and highly selective inhibitors of MMP-9 and MMP-2. In addition, these compounds were orally active in animal models of tumor growth and metastasis. These results revealed the potential of the N-sulfonylamino acid derivatives as a new type of candidate drug for the treatment of cancer.

Chemokines and their receptors are essential for leukocyte trafficking, and also implicated in cancer metastasis to specific organs. We have recently demonstrated that CXCR3 plays a critical role in metastasis of mouse melanoma cells to lymph nodes. Here, we show that some human colon cancer cell lines express CXCR3 constitutively. We constructed cells that expressed CXCR3 cDNA ('DLD-1-CXCR3'), and compared with nonexpressing controls by rectal transplantation in nude mice. Although both cell lines disseminated to lymph nodes at similar frequencies at 2 weeks, DLD-1-CXCR3 expanded more rapidly than the control in 4 weeks. In 6 weeks, 59% of mice inoculated with DLD1-CXCR3 showed macroscopic metastasis in para-aortic lymph nodes, whereas only 14% of those with the control (Po0.05). In contrast, metastasis to the liver or lung was rare, and unaffected by CXCR3 expression. In clinical colon cancer samples, we found expression of CXCR3 in 34% cases, most of which had lymph node metastasis. Importantly, patients with CXCR3-positive cancer showed significantly poorer prognosis than those without CXCR3, or those expressing CXCR4 or CCR7. These results indicate that activation of CXCR3 with its ligands stimulates colon cancer metastasis preferentially to the draining lymph nodes with poorer prognosis.

Chitinase 3-like 1 (CHI3L1), one of mammalian members of the chitinase family, is expressed in several types of human cancer, and elevated serum level of CHI3L1 is suggested to be a biomarker of poor prognosis in advanced cancer patients. However, the overall biological function of CHI3L1 in human cancers still remains unknown. Studies were performed to characterize the role of CHI3L1 in cancer pathophysiology utilizing human colorectal cancer samples and human cell lines. Plasma protein and tissue mRNA expression levels of CHI3L1 in colorectal cancer were strongly upregulated. Immunohistochemical analysis showed that CHI3L1 was expressed in cancer cells and CHI3L1 expression had a significant association with the number of infiltrated macrophages and microvessel density. By utilizing trans-well migration and tube formation assays, overexpression of CHI3L1 in SW480 cells (human colon cancer cells) enhanced the migration of THP-1 cells (human macrophage cells) and HUVECs (human endothelial cells), and the tube formation of HUVECs. The knockdown of CHI3L1 by RNA interference or the neutralization of CHI3L1 by anti-CHI3L1 antibody displayed strong suppression of CHI3L1-induced migration and tube formation. Cell proliferation assay showed that CHI3L1 overexpression significantly enhanced the proliferation of SW480 cells. ELISA analysis showed that CHI3L1 increased the secretion of inflammatory chemokines, IL-8 and MCP-1, from SW480 cells through mitogen-activated protein kinase (MAPK) signaling pathway. Both neutralization of IL-8 or MCP-1 and inhibition or knockdown of MAPK in SW480 cells significantly inhibited CHI3L1-induced migration and tube formation. In a xenograft mouse model, overexpression of CHI3L1 in HCT116 cells (human colon cancer cells) enhanced the tumor growth as well as macrophage infiltration and microvessel density. In conclusion, CHI3L1 expressed in colon cancer cells promotes cancer cell proliferation, macrophage recruitment and angiogenesis. Thus, the inhibition of CHI3L1 activity may be a novel therapeutic strategy for human colorectal cancer.

BackgroundLaparoscopic rectal surgery involving rectal transection and anastomosis with stapling devices is technically difficult. The aim of this study was to evaluate the risk factors for anastomotic leakage (AL) after laparoscopic low anterior resection (LAR) with double-stapling technique (DST) anastomosis.MethodsThis was a retrospective single-institution study of 154 rectal cancer patients who underwent laparoscopic LAR with DST anastomosis between June 2005 and August 2013. Patient-, tumor-, and surgery-related variables were examined by univariate and multivariate analyses. The outcome of interest was clinical AL.ResultsThe overall AL rate was 12.3 % (19/154). In univariate analysis, tumor size (P = 0.001), operative time (P = 0.049), intraoperative bleeding (P = 0.037), lateral lymph node dissection (P = 0.009), multiple firings of the linear stapler (P = 0.041), and precompression before stapler firings (P = 0.008) were significantly associated with AL. Multivariate analysis identified tumor size (odds ratio [OR] 4.01; 95 % confidence interval [CI] 1.25–12.89; P = 0.02) and precompression before stapler firings (OR 4.58; CI 1.22–17.20; P = 0.024) as independent risk factors for AL. In particular, precompression before stapler firing tended to reduce the AL occurring in early postoperative period.ConclusionsUsing appropriate techniques, laparoscopic LAR with DST anastomosis can be performed safely without increasing the risk of AL. Important risk factors for AL were tumor size and precompression before stapler firings.

ICG fluorescence imaging is useful for assessing anastomotic perfusion in colorectal surgery, which can result in more precise operative decisions tailored for an individual patient.