Glycolipid antigens for treating hepatic colorectal cancer metastases and their effect on the therapeutic efficacy of live attenuated Listeria monocytogenes

Imaging α-GalCer-activated iNKT cells in a hepatic metastatic environment

Colorectal cancer patients frequently develop liver metastases after, and perhaps as a consequence of, lifesaving surgical resection of the primary tumor. This creates a potential opportunity for prophylactic metastatic treatment with novel immunostimulatory molecules. Here, we used state-of-the-art intravital imaging of an experimental liver metastasis model to visualize the early behavior and function of invariant (i)NKT cells stimulated with α-galactosylceramide (α-GalCer). Intravenous α-GalCer prior to tumor cell seeding in the liver significantly inhibited tumor growth. However, some seeding tumor cells survived. A multiple dosing regimen reduced tumor burden and prolonged the life of mice, whereas tumors returned within 5 days after a single dose of α-GalCer. With multiple doses of α-GalCer, iNKT cells increased in number and granularity (as did NK cells). As a result, the total number of contacts and time in contact with tumors increased substantially. In the absence of iNKT cells, the beneficial effect of α-GalCer was lost. Robust cytokine production dissipated over time. Repeated therapy, even after cytokine dissipation, led to reduced tumor burden and prolonged survival. Serial transplantation of tumors exposed to α-GalCer-activated iNKT cells did not induce greater resistance, suggesting no obvious epigenetic or genetic immunoediting in tumors exposed to activated iNKT cells. Very few tumor cells expressed CD1d in this model, and as such, adding monomers of CD1d-α-GalCer further reduced tumor growth. The data suggest early and repeated stimulation of iNKT cells with α-GalCer could have direct therapeutic benefit for colorectal cancer patients that develop metastatic liver disease.

CD146 protein as a marker to predict postoperative liver metastasis in colorectal cancer

OBJECTIVE

To study the expression and regulatory effects of CD146 protein in colorectal cancer and the correlation between CD146 protein expression and the prognosis of colorectal cancer.

MATERIALS AND METHODS

The CD146 protein level was detected by immunohistochemistry staining. The relationship between CD146 expression and clinicopathological parameters of colorectal cancer was determined.

RESULTS

It was observed that 216 (20.00%) of the 1080 cases positively expressed CD146 protein. Univariate analyses indicated that CD146 expression was related to histological grade, Duke's stage, and liver metastasis (p=0.001, 0.001, and 0.001, respectively). Spearman correlation analysis showed that CD146 expression has line correlation to histological grade, Duke's stage, and liver metastasis (p=0.02, 0.01 and 0.001, respectively). After multivariate analysis, Duke's stage and CD146 were related to liver metastasis (p=0.01 and 0.001, respectively). In the Cox regression test, histological grade, Duke's stage, and CD146 were detected as the independent prognostic factors (p=0.045, 0.01, and 0.001, respectively).

CONCLUSIONS

CD146 protein may be a potential biomarker for the postoperative liver metastasis of colorectal cancer.