B16F10 Melanoma Tumor Growth Research Articles

Abstract 4984: Generation of an RGD containing soluble pro-inflammatory form of the XL313 cryptic collagen epitope during tumor growth and inflammation.

Abstract Evidence indicates that malignant tumor progression depends not only on tumor cells themselves, but also on stromal cells of the malignant lesion including tumor-associated macrophages (TAMs). TAMs have been suggested to contribute to changes in the extracellular matrix (ECM) through remodeling of architectural proteins like type-I collagen. Our previous studies have shown that remodeling of the ECM results in localized triggering of what we have termed “biomechanical ECM switches” resulting in exposure of cryptic ECM epitopes. In this regard, collagen has a number of Arg-Gly-Asp (RGD) containing cryptic sites and soluble RGD containing reagents are currently being developed for the treatment of malignant tumors. However, it is not known if the distinct cryptic RGD elements in type-I collagen are functionally redundant or if specific flanking sequences convey differential control of cellular behavior. In this regard, we previously generated a series of monoclonal antibodies (Mabs) that target distinct RGD containing cryptic sites of type-I collagen. One of these Mabs designated XL313 exhibits selective recognition of the conserved RGDKGE cryptic element and significantly (P<0.05) inhibits B16F10 melanoma tumor growth as well as growth factor induced angiogenesis and inflammation in vivo. Interestingly, Mab XL166, selective for the RGDAPG collagen cryptic eptitope, showed no effect on tumor growth, angiogenesis or inflammation. To evaluate the role of the XL313 epitope in angiogenesis and inflammation in more detail, we examined its exposure in inflammed tissues. While the XL313 epitope was detected in close proximity to angiogenic blood vessels, the majority of the epitope localized to what appeared to be inflammatory infiltrates, suggesting a role for inflammatory cells in generating the XL313 collagen element. Here we provide evidence that a soluble form of the RGD containing XL313 epitope is generated by macrophages through a mechanism dependent in part on cathepsin activity, as a cathepsin inhibitor reduced generation of the XL313 epitope. Importantly, elevated levels of a circulating form of the XL313 epitope were detected, while lower levels of the related XL166 RGD epitope were observed in these samples following FGF-induced inflammation of the Chick CAM. Given these findings, we sought to determine whether the soluble XL313 epitope might induce inflammation in vivo. Our findings indicate that the RGD containing XL313 epitope, but not the XL166, epitope significantly (P<0.05) induced inflammation in vivo, suggesting that generation of distinct RGD containing collagen peptides might have distinct roles in inflammation. Our findings are consistent with a novel mechanism by which generation of a specific highly conserved cryptic RGD collagen peptide might enhance rather than inhibit inflammation in vivo, and thus contribute to tumor progression. Citation Format: Jacquelyn J. Ames, Jennifer Caron, Liangru Contois, Peter Brooks. Generation of an RGD containing soluble pro-inflammatory form of the XL313 cryptic collagen epitope during tumor growth and inflammation. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4984. doi:10.1158/1538-7445.AM2013-4984

Host-Derived MCP-1 and MIP-1α Regulate Protective Anti-Tumor Immunity to Localized and Metastatic B16 Melanoma

Leukocytic infiltration into malignant melanoma lesions is tightly regulated by chemokines. To assess the role of the CC chemokines monocyte chemotactic protein-1 (MCP-1/chemokine ligand 2) and macrophage inflammatory protein-1α (MIP-1α/chemokine ligand 3) in this process, s.c. primary and metastatic B16 F10 melanoma tumor growth levels were examined in mice lacking MCP-1 or MIP-1α. Primary s.c. B16 F10 melanoma growth was augmented by loss of MCP-1 or MIP-1α. Similarly, lung metastasis was enhanced by the deficiency of MCP-1 or MIP-1α. Enhanced tumor outgrowth was associated with decreased percentages of infiltrating CD4(+) T cells, CD8(+) T cells, and natural killer cells. In the absence of MCP-1 or MIP-1α, melanoma outgrowth was correlated with reduced local expression of interferon-γ, IL-6, tumor necrosis factor-α, and transforming growth factor-β. Among these cytokines, reduced expression levels of interferon-γ and tumor necrosis factor-α on leukocytes from the spleen were associated with the development of lung metastasis in chemokine-deficient mice. The local s.c. administration of these four cytokines significantly augmented another chemokine's expression and suppressed primary melanoma growth in mice deficient for MCP-1 or MIP-1α. The s.c. injection of MCP-1 or MIP-1α significantly inhibited the primary tumor growth in wild-type mice. These results indicate that host-derived MCP-1 and MIP-1α regulate protective anti-tumor immunity to B16 F10 melanoma by promoting lymphocyte infiltration into the tumor and subsequent cytokine production.

Abstract 1549: Regulation of inflammation and tumor growth by the novel XL313 cryptic ECM element

Abstract Experimental evidence suggests that multiple cell types within the tumor microenvironment such as fibroblast, endothelial cells and inflammatory cells contribute to tumor growth. Recent evidence indicates that biomechanical alterations in the structural integrity of ECM proteins may result in exposure of cryptic regulatory elements that play roles in differentially controlling cell signaling pathways. Therefore, exposure of cryptic regulatory sites may function as biomechanical switches, allowing various cell populations to respond in distinct ways to localized structural alterations within the tumor microenvironment. Thus, identifying and characterizing biomechanical ECM switches may provide selective new therapeutic targets to regulate tumor progression. In this regard, triple helical collagen has numerous RGD containing cryptic integrin binding sites. However, it is not known whether all these cryptic RGD elements are functionally redundant or whether distinct flanking sequences may convey differential control of cellular behavior. To examine potential functional differences between distinct RGD containing cryptic sites, we generated a series of Mabs directed to synthetic RGD containing peptides found within type-I collagen. One Mab termed XL313 selectively recognized a cryptic element containing the amino acid sequence RGDKGE, but failed to bind other RGD containing sites. Mab XL313 failed to recognize intact triple helical collagen, but did bind proteolytically cleaved collagen. Importantly, Mab XL313 significantly (P<0.05) inhibited B16F10 melanoma tumor growth by greater than 50%. Given the possibility that inflammation may contribute to tumor development, we examined the impact of the XL313 epitope on growth factor induced inflammation. Our studies suggest that the XL313 cryptic site may regulate inflammation as Mab XL313 significantly (P<0.05) inhibited inflammation / CAM thickening in the chick embryo model. Collectively, our studies suggest that the XL313 biomechanical ECM switch may represent an important new therapeutic target for the control of tumor growth and inflammation. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1549. doi:10.1158/1538-7445.AM2011-1549

Suramin augments the antitumor and antimetastatic activity of pentoxifylline in B16F10 melanoma

Rapid tumor growth and metastasis are 2 major problems associated with treatment of malignant melanoma. Therefore, drugs that can intervene these processes are of clinical importance. Pentoxifylline (PTX), a methyl xanthine derivative, has been shown to inhibit B16F10 melanoma tumor growth and metastasis. We hypothesized that suramin when combined with PTX enhances its antineoplastic effects, which we have examined using the B16F10 mouse melanoma model. Suramin in simultaneous or sequential combination potentiated the cytotoxic effects of PTX on B16F10 cells. PTX arrested cells in the G0-G1 phase and suramin augmented the effects. Both the drugs inhibited F10 adhesion to laminin, matrigel and collagen type IV and showed enhanced inhibition in combination The combination also demonstrated significantly higher inhibition in cell motility (p = 0.002) and invasion through matrigel (p = 0.005) as compared to the single agents. Suramin synergized with PTX in its effects on secretion of MMP-9 gelatinase. DBA2/J mice implanted with intradermal B16F10 tumor were used as a model to study tumor growth. Animals were intratumorally treated with 50 mg/kg of PTX, 10 mg/kg of suramin and their combinations. Simultaneous administration of the drugs inhibited tumor growth by 5- to 6-folds. Tumor growth was completely blocked in sequential regimen with regression in some cases. The number and size of metastatic nodules on lung was also reduced significantly by the combination treatment. In conclusion, the novel combination of PTX and suramin has synergistic antitumor and antimetastatic activity in B16F10 melanoma and may be a promising approach in treatment of patients suffering from malignant melanoma.