Augmented antitumour effects of combination therapy with TNP-470 and chemoimmunotherapy in mice

NVP-LDE225, a potent and selective SMOOTHENED antagonist reduces melanoma growth in vitro and in vivo

Melanoma is one of the most aggressive cancers and its incidence is increasing worldwide. So far there are no curable therapies especially after metastasis. Due to frequent mutations in members of the mitogen-activated protein kinase (MAPK) signaling pathway, this pathway is constitutively active in melanoma. It has been shown that the SONIC HEDGEHOG (SHH)-GLI and MAPK signaling pathway regulate cell growth in many tumors including melanoma and interact with each other in the regulation of cell proliferation and survival.

Here we show that the SHH-GLI pathway is active in human melanoma cell lines as they express downstream target of this pathway GLI1. Expression of GLI1 was significantly higher in human primary melanoma tissues harboring BRAF^V600E mutation than those with wild type BRAF. Pharmacologic inhibition of BRAF^V600E in human melanoma cell lines resulted in decreased expression of GLI1 thus demonstrating interaction of SHH-GLI and MAPK pathways. Inhibition of SHH-GLI pathway by the novel small molecule inhibitor of smoothened NVP-LDE225 was followed by inhibition of cell growth and induction of apoptosis in human melanoma cell lines, interestingly with both BRAF^V600E and BRAF^{Wild Type} status. NVP-LDE225 was potent in reducing cell proliferation and inducing tumor growth arrest in vitro and in vivo, respectively and these effects were superior to the natural compound cyclopamine.

Finally, we conclude that inhibition of SHH-GLI signaling pathway in human melanoma by the specific smoothened inhibitor NVP-LDE225 could have potential therapeutic application in human melanoma even in the absence of BRAF^V600E mutation and warrants further investigations.

Inhibitory effect of herbal remedy PERVIVO and anti-inflammatory drug sulindac on L-1 sarcoma tumor growth and tumor angiogenesis in Balb/c mice

Anticancer activity of many herbs was observed for hundreds of years. They act as modifiers of biologic response, and their effectiveness may be increased by combining multiple herbal extracts . PERVIVO, traditional digestive herbal remedy, contains some of them, and we previously described its antiangiogenic activity. Numerous studies documented anticancer effects of nonsteroidal anti-inflammatory drugs. We were the first to show that sulindac and its metabolites inhibit angiogenesis. In the present paper the combined in vivo effect of multicomponent herbal remedy PERVIVO and nonsteroidal anti-inflammatory drug sulindac on tumor growth, tumor angiogenesis, and tumor volume in Balb/c mice was studied. These effects were checked after grafting cells collected from syngeneic sarcoma L-1 tumors into mice skin. The strongest inhibitory effect was observed in experimental groups treated with PERVIVO and sulindac together. The results of our investigation showed that combined effect of examined drugs may be the best way to get the strongest antiangiogenic and antitumor effect.

Polo-like kinase 1 is a potential therapeutic target in human melanoma

Exploration of the human melanoma cell-cycle pathway can lead to identification of new therapeutic targets. By gene set enrichment analysis, we identified the cell-cycle pathway and its member polo-like kinase 1 (Plk-1) to be significantly overexpressed in primary melanomas and in melanoma metastases. In vitro expression of Plk-1 was peaked at the G2/M phase of the cell cycle. Plk-1 knockdown/inhibition led to induction of apoptosis, which was caspase-3/8-dependent and p53-independent, and involved BID and Bcl-2 proteins. Comparative genomic hybridization/single-nucleotide polymorphism arrays showed no genetic alteration in the Plk-1 locus. Previous suggestions and significant enrichment of the mitogen-activated protein kinase (MAPK) signaling pathway pointed to potential regulation of Plk-1 by MAPK signaling. Inhibition of this pathway resulted in decreased Plk-1 expression as a consequence of G1 cell-cycle arrest rather than direct regulation of Plk-1. Inhibition of MAPK and Plk-1 had an additive effect on reduced cell viability. This study shows that in human melanoma, Plk-1 expression is dynamically regulated during the cell cycle, knockdown of Plk-1 leads to apoptotic cell death, and that a combination of Plk-1 and MAPK inhibition has an additive effect on melanoma cell viability. We conclude that combined inhibition of Plk-1 and MAPK could be a potentially attractive strategy in melanoma therapy.

Augmented antitumor effects of combination therapy with VEGF antibody and cisplatin on murine B16F10 melanoma cells

Our previous studies with EAC tumor model demonstrated that a VEGF polyclonal antibody combined with cisplatin inhibited tumor growth. Here we report the antitumor effect of VEGF antibody plus cisplatin on a murine metastatic tumor model specially emphasizing its effect on different angiogenic parameters both in vitro and in vivo. Mouse B16F10 melanoma cells were cultured in vitro in DMEM media containing 10% FBS, nonessential amino acids and antibiotics in a 5% CO(2) incubator at 37 degrees C and the effect of VEGF antibody singly and in combination with cisplatin on this cell was assessed by MTT assay, matrigel invasion study and MMP-9 expression study in vitro. In vivo studies were performed by two tumor models viz B16F10 solid tumor model and B16LuF10 lung tumor model. The mice treated with VEGF antibody (PAb) alone, cisplatin alone and combination of VEGF antibody and cisplatin on alternative days from the next day of tumor transplantation. Antitumor as well as antiangiogenic efficacy was monitored by measuring tumor burden, survivability, MVD measurement, serum NO value measurement and bcl-2 expression study. It was observed that administration of combined therapy with VEGF antibody and cisplatin augmented antitumor activity in B16F10 melanoma models than the either agents alone. Thus our experiments show a successful VEGF antibody based combination therapy with cisplatin and suggests that the enhancement of antitumor activity could be explained by a concomitant effect on both endothelial and tumor cell compartment.