IFN-γ is essential for the inhibition of B16BL6 melanoma lung metastasis in chronic alcohol drinking mice

Alcohol as a Non-UV Social-Environmental Risk Factor for Melanoma

Although cancer mortality has declined among the general population, the incidence of melanoma continues to rise. While identifying high-risk cohorts with genetic risk factors improves public health initiatives and clinical care management, recognizing modifiable risk factors such as social-environmental risk factors would also affect the methods of patient outreach and education. One major modifiable social-environmental risk factor associated with melanoma is ultraviolet (UV) radiation. However, not all forms of melanoma are correlated with sun exposure or occur in sun-exposed areas. Additionally, UV exposure is rarely associated with tumor progression. Another social-environmental factor, pregnancy, does not explain the sharply increased incidence of melanoma. Recent studies have demonstrated that alcohol consumption is positively linked with an increased risk of cancers, including melanoma. This perspective review paper summarizes epidemiological data correlating melanoma incidence with alcohol consumption, describes the biochemical mechanisms of ethanol metabolism, and discusses how ethanol and ethanol metabolites contribute to human cancer, including melanoma.

Hepato-entrained B220+CD11c+NK1.1+ cells regulate pre-metastatic niche formation in the lung

Primary tumours establish metastases by interfering with distinct organs. In pre-metastatic organs, a tumour-friendly microenvironment supports metastatic cells and is prepared by many factors including tissue resident cells, bone marrow-derived cells and abundant fibrinogen depositions. However, other components are unclear. Here, we show that a third organ, originally regarded as a bystander, plays an important role in metastasis by directly affecting the pre-metastatic soil. In our model system, the liver participated in lung metastasis as a leucocyte supplier. These liver-derived leucocytes displayed liver-like characteristics and, thus, were designated hepato-entrained leucocytes (HepELs). HepELs had high expression levels of coagulation factor X (FX) and vitronectin (Vtn) and relocated to fibrinogen-rich hyperpermeable regions in pre-metastatic lungs; the cells then switched their expression from Vtn to thrombospondin, both of which were fibrinogen-binding proteins. Cell surface marker analysis revealed that HepELs contained B220⁺CD11c⁺NK1.1⁺ cells. In addition, an injection of B220⁺CD11c⁺NK1.1⁺ cells successfully eliminated fibrinogen depositions in pre-metastatic lungs via FX Moreover, B220⁺CD11c⁺NK1.1⁺ cells demonstrated anti-metastatic tumour ability with IFNγ induction. These findings indicate that liver-primed B220⁺CD11c⁺NK1.1⁺ cells suppress lung metastasis.

The immunomodulatory, antitumor and antimetastatic responses of melanoma-bearing normal and alcoholic mice to sunitinib and ALT-803: a combinatorial treatment approach

ALT-803, a novel IL-15/IL-15 receptor alpha complex, and the tyrosine kinase inhibitor, sunitinib, were examined for their single and combined effects on the growth of subcutaneous B16BL6 melanoma and on lymph node and lung metastasis. The study was conducted in immunocompetent C57BL/6 mice drinking water (Water mice) and in mice that chronically consumed alcohol (Alcohol mice), which are deficient in CD8(+) T cells. Sunitinib inhibited melanoma growth and was more effective in Alcohol mice. ALT-803 did not alter tumor growth or survival in Water or Alcohol mice. Combined ALT-803 and sunitinib inhibited melanoma growth and increased survival, and these effects were greater than sunitinib alone in Water mice. ALT-803 and alcohol independently suppressed lymph node and lung metastasis, whereas sunitinib alone or in combination with ALT-803 increased lymph node and lung metastasis in Water and Alcohol mice. Initially, ALT-803 increased IFN-γ-producing CD8(+)CD44(hi) memory T cells and CD8(+)CD44(hi)CD62L(lo) effector memory T cells and sunitinib decreased immunosuppressive MDSC and T regulatory cells (Treg). However, the impact of these treatments diminished with time. Subcutaneous tumors from Water mice showed increased numbers of CD8(+) T cells, CD8(+)CD44(hi) T cells, NK cells, and MDSC cells and decreased Treg cells after ALT-803 treatment.

A Preclinical Model of Chronic Alcohol Consumption Reveals Increased Metastatic Seeding of Colon Cancer Cells in the Liver

Liver metastasis is the main cause of death from colorectal cancer. Alcohol consumption impacts liver function and is suggested to be an independent risk factor for liver metastasis of colorectal cancer, but no experimental evidence supporting this hypothesis has been demonstrated to date. In this study, we investigated the effect of alcohol intake on liver metastasis. We examined colon cancer cell spread from the spleen in mice provided with water (control group), alcohol for 4 weeks before tumor injection (prealcohol), alcohol for 3 weeks after tumor injection (postalcohol), or alcohol throughout the 7-week study (alcohol). Alcohol intake significantly increased hepatic metastatic burden in the prealcohol (2.4-fold, P < 0.001), postalcohol (2.0-fold, P < 0.01), and alcohol groups (2.2-fold, P < 0.001). A fluorescence-based metastasis tracking assay also confirmed an alcohol-induced increase in the abundance of tumor cells in the liver (2.5-fold, P < 0.001). Investigation of the host microenvironment revealed an alcohol-induced inflammatory response marked by elevated TNFα, IL1β, IL6, and IFNγ protein levels, as well as increased expression of intercellular molecule-1 (ICAM1) in hepatic tissues after 4 weeks of alcohol consumption. Moreover, the peripheral blood of mice provided with alcohol for 4 weeks exhibited reduced natural killer and CD8(+) T-cell counts. Collectively, our findings suggest that chronic alcohol consumption accelerates liver metastasis of colorectal cancer cells through alterations to the liver microenvironment and inactivation of immune surveillance. Cancer Res; 76(7); 1698-704. ©2016 AACR.

Chronic alcohol consumption inhibits melanoma growth but decreases the survival of mice immunized with tumor cell lysate and boosted with α-galactosylceramide

Alcohol consumption increases the incidence of multiple types of cancer. However, how chronic alcohol consumption affects tumor progression and host survival remains largely unexplored. Using a mouse B16BL6 melanoma model, we studied the effects of chronic alcohol consumption on s.c. tumor growth, iNKT cell antitumor immune response, and host survival. The results indicate that although chronic alcohol consumption inhibits melanoma growth, this does not translate into increased host survival. Immunizing mice with a melanoma cell lysate does not significantly increase the median survival of water-drinking, melanoma-bearing mice, but significantly increases the median survival of alcohol-consuming, melanoma-bearing mice. Even though survival is extended in the alcohol-consuming mice after immunization, the median survival is not different from the immunized mice in the water-drinking group. Immunization with tumor cell lysate combined with α-galatosylceramide activation of iNKT cells significantly increases host survival of both groups of melanoma-bearing mice compared to their respective non-immunized counterparts; however, the median survival of the alcohol-consuming group is significantly lower than that of the water-drinking group. Alcohol consumption increases NKT cells in the thymus and blood and skews NKT cell cytokine profile from Th1 dominant to Th2 dominant in the tumor-bearing mice. In summary, these results indicate that chronic alcohol consumption activates the immune system, which leads to the inhibition of s.c. melanoma growth and enhances the immune response to immunization with melanoma lysate. With tumor progression, alcohol consumption accelerates iNKT cell dysfunction and compromises antitumor immunity, which leads to decreased survival of melanoma-bearing mice.

Alcohol consumption and antitumor immunity: dynamic changes from activation to accelerated deterioration of the immune system

The molecular mechanisms of how alcohol and its metabolites induce cancer have been studied extensively. However, the mechanisms whereby chronic alcohol consumption affects antitumor immunity and host survival have largely been unexplored. We studied the effects of chronic alcohol consumption on the immune system and antitumor immunity in mice inoculated with B16BL6 melanoma and found that alcohol consumption activates the immune system leading to an increase in the proportion of IFN-γ-producing NK, NKT, and T cells in mice not injected with tumors. One outcome associated with enhanced IFN-γ activation is inhibition of melanoma lung metastasis. However, the anti-metastatic effects do not translate into increased survival of mice bearing subcutaneous tumors. Continued growth of the subcutaneous tumors and alcohol consumption accelerates the deterioration of the immune system, which is reflected in the following: (1) inhibition in the expansion of memory CD8+ T cells, (2) accelerated decay of Th1 cytokine-producing cells, (3) increased myeloid-derived suppressor cells, (4) compromised circulation of B cells and T cells, and (5) increased NKT cells that exhibit an IL-4 dominant cytokine profile, which is inhibitory to antitumor immunity. Taken together, the dynamic effects of alcohol consumption on antitumor immunity are in two opposing phases: the first phase associated with immune stimulation is tumor inhibitory and the second phase resulting from the interaction between the effects of alcohol and the tumor leads to immune inhibition and resultant tumor progression.

Effects of Alcohol on Tumor Growth, Metastasis, Immune Response, and Host Survival

Most research involving alcohol and cancer concerns the relationship between alcohol consumption and cancer risk and the mechanisms of carcinogenesis. This review relates the amount and duration of alcohol intake in humans and in animal models of cancer to tumor growth, angiogenesis, invasion, metastasis, immune response, and host survival in specific types and subtypes of cancer. Research on the influence of alcohol drinking on human cancer patients is limited. Although there is more information in animal models of cancer, many aspects still are ill defined. More research is needed to define the mechanisms that underlie the role of alcohol on cancer progression in both animals and humans. Activation of the immune system can play a positive role in keeping cancer under control, but this also can facilitate cancer progression. Additionally, a functional immune system is required for cancer patients to achieve an optimal response to conventional chemotherapy. Insight into the underlying mechanisms of these interactions could lead to effective immunotherapeutic approaches to treat alcoholics with cancer. Defining the epigenetic mechanisms that modulate cancer progression also has great potential for the development of new treatment options not only for treating alcoholics with cancer but also for treating other alcohol-induced diseases.