RANK/RANKL axis promotes migration, invasion, and metastasis of osteosarcoma via activating NF-κB pathway.

Osteosarcoma (OS) is one of the most prevalent primary bone tumors with a high degree of metastasis and poor prognosis. Epithelial-to-mesenchymal transition (EMT) is a cellular mechanism that contributes to the invasion and metastasis of cancer cells, and OS cells have been reported to exhibit EMT-like characteristics. Our previous studies have shown that the interaction between tumor necrosis factor superfamily member 11 (TNFRSF11A; also known as RANK) and its ligand TNFSF11 (also known as RANKL) promotes the EMT process in breast cancer cells. However, whether the interaction between RANK and RANKL enhances aggressive behavior by inducing EMT in OS cells has not yet been elucidated. In this study, we showed that the interaction between RANK and RANKL increased the migration, invasion, and metastasis of OS cells by promoting EMT. Importantly, we clarified that the RANK/RANKL axis induces EMT by activating the nuclear factor-kappa B (NF-κB) pathway. Furthermore, the NF-κB inhibitor dimethyl fumarate (DMF) suppressed migration, invasion, and EMT in OS cells. Our results suggest that the RANK/RANKL axis may serve as a potential tumor marker and promising therapeutic target for OS metastasis. Furthermore, DMF may have clinical applications in the treatment of lung metastasis in patients with OS.

HER3/Akt/mTOR pathway is a key therapeutic target for the reduction of triple­negative breast cancer metastasis via the inhibition of CXCR4 expression.

Triple­negative breast cancer (TNBC), a highly metastatic subtype of breast cancer, and it has the worst prognosis among all subtypes of breast cancer. However, no effective systematic therapy is currently available for TNBC metastasis. Therefore, novel therapies targeting the key molecular mechanisms involved in TNBC metastasis are required. The present study examined whether the expression levels of human epidermal growth factor receptor 3 (HER3) were associated with the metastatic phenotype of TNBC, and evaluated the potential of HER3 as a therapeutic target in vitro and in vivo. A new highly metastatic 4T1 TNBC cell line, termed 4T1­L8, was established. The protein expression levels in 4T1­L8 cells were measured using luminex magnetic bead assays and western blot analysis. The HER3 expression levels and distant metastasis­free survival (DMFS) in TNBC were analyzed using Kaplan­Meier Plotter. Transwell migration and invasion assays were performed to detect migration and invasion. The anti­metastatic effects were determined in an experimental mouse model of metastasis. The results revealed that the increased expression of the HER3/Akt/mTOR pathway was associated with a greater level of cell migration, invasion and metastasis of TNBC cells. In addition, it was found that high expression levels of HER3 were associated with a poor DMFS. The inhibition of the HER3/Akt/mammalian target of rapamycin (mTOR) pathway decreased the migration, invasion and metastasis of TNBC cells by decreasing the expression of C­X­C chemokine receptor type 4 (CXCR4). Furthermore, treatment of metastatic TNBC cells with everolimus inhibited their migration, invasion and metastasis by decreasing CXCR4 expression. Thus, targeting the HER3/Akt/mTOR pathway opens up a new avenue for the development of therapeutics against TNBC metastasis; in addition, everolimus may prove to be an effective therapeutic agent for the suppression of TNBC metastasis.

Inhibition of yes-associated protein suppresses migration, invasion, and metastasis in non-small cell lung cancer in vitro and in vivo.

Non-small cell lung cancer (NSCLC) is a highly aggressive cancer with one of the most prevalent malignant tumors. Metastasis in NSCLC is the major cause of treatment failure and cancer-related deaths. Yes-associated protein (YAP) is a transcriptional coactivator regulated by the evolutionarily conserved Hippo signaling pathway that regulates organ size, growth, and regeneration. YAP is highly expressed in several malignant tumor types. Furthermore, YAP promotes tumor initiation and/or progression in various types of cancer. However, it is unclear whether YAP contributes to the metastasis in NSCLC and serves as a useful therapeutic target. Here, we investigated whether levels of YAP correlate with metastatic phenotype in NSCLC cells and serve as a useful therapeutic target. We found that high levels of YAP associate with high cell migration, invasion, and metastasis in NSCLC cell lines. Furthermore, YAP siRNA decreased the migration and invasion in NSCLC cells. Additionally, verteporfin, an agent used for the treatment of symptomatic polypoidal choroidal vasculopathy, decreased the expression of YAP and inhibited migration, invasion, and metastasis in NSCLC cells. Thus, the study suggests that targeting YAP may present a new avenue to develop therapeutics against metastasis in NSCLC and that verteporfin has potential molecular therapeutic strategy for the treatment of metastatic NSCLC.

Sorafenib treatment of metastatic melanoma with c-Kit aberration reduces tumor growth and promotes survival.

Melanomas are highly malignant tumors that readily metastasize and have poor prognosis. Targeted therapy is a cornerstone of treatment for patients with melanoma. Although c-Kit gene aberration has found in 5-10% of melanoma cases, research on c-Kit inhibitors for melanoma with c-Kit aberration have been disappointing. Sorafenib is a tyrosine kinase inhibitor, whose targets include c-Kit, platelet derived growth factor receptor (PDGFR), VEGFR and RAF. The present study aimed to examine the effect of sorafenib on metastatic melanoma with c-Kit aberration. Cell viability was assessed via trypan blue assay. Migration and invasion were analyzed using cell culture inserts. The anti-metastatic effects and antitumour activity of sorafenib were determined in an in vivo model. Protein expression was detected via western blotting, and the expression of MMP and very late antigen (VLA) was detected via reverse transcription-quantitative PCR. It was identified that sorafenib decreased cell viability, migration and invasion in vitro. Furthermore, sorafenib inhibited metastasis and tumor growth in vivo. Mechanistically, sorafenib inhibited c-Kit, PDGFR, VEGFR, B-Raf and c-Raf phosphorylation both in vitro and in vivo. In addition, sorafenib reduced the expression levels of MMPs and VLA. Importantly, there was a significant effect of sorafenib treatment on overall survival in mice. Collectively, this study suggests that sorafenib may serve as a novel therapeutic option for melanoma with c-Kit dysregulation.

AT9283 exhibits antiproliferative effect on tyrosine kinase inhibitor­sensitive and ­resistant chronic myeloid leukemia cells by inhibition of Aurora A and Aurora B.

Imatinib is the gold standard in the conventional treatment of chronic myeloid leukemia (CML). However, some patients become resistant to imatinib therapy. To overcome this resistance, second­generation (dasatinib, nilotinib, and bosutinib) and third­generation (ponatinib) tyrosine kinase inhibitors (TKIs) have been developed and have been shown to be effective against refractory CML. Although these TKIs provide many benefits for patients with CML, advanced patients show resistance even to these TKIs. Therefore, novel therapeutic strategies are urgently needed for the treatment of TKI­resistant CML patients. AT9283 is a multi­targeted kinase inhibitor with potent activity against Janus kinase (JAK), Aurora kinases, and Abl. In the present study, we showed that AT9283 significantly decreased the cell viability of both TKI­sensitive and TKI­resistant CML cells as determined by trypan blue exclusion assay. In addition, cell cycle analysis, Annexin V assay, and caspase­3/7 activity assay revealed that AT9283 increased the cell population in the G2/M phase and induced apoptosis. We investigated the molecular mechanisms underlying the decrease in cell viability upon treatment with AT9283 by western blotting. Interestingly, our results showed that AT9283 inhibited the expression of Aurora A, Aurora B, and downstream Histone H3 phosphorylation. In contrast, we observed no changes in the levels of Bcr­Abl, signal transducer and activator of transcription 3 (STAT3), extracellular signal­regulated kinase (ERK), and Akt phosphorylation. In addition, we found that AMG900, a selective Aurora A and Aurora B inhibitor, increased the G2/M phase cell population and induced apoptosis via inhibition of Aurora A and Aurora B in both TKI­sensitive and TKI­resistant CML cells. Our studies show that Aurora A and Aurora B are promising therapeutic targets for TKI­sensitive and TKI­resistant CML, and AT9283 may have potential clinical applications for the treatment of TKI­resistant CML patients.