Embryonic protein NODAL regulates the breast tumor microenvironment by reprogramming cancer-derived secretomes.

The tumor microenvironment (TME) is an important mediator of breast cancer progression. Cancer-associated fibroblasts constitute a major component of the TME and may originate from tissue-associated fibroblasts or infiltrating mesenchymal stromal cells (MSCs). The mechanisms by which cancer cells activate fibroblasts and recruit MSCs to the TME are largely unknown, but likely include deposition of a pro-tumorigenic secretome. The secreted embryonic protein NODAL is clinically associated with breast cancer stage and promotes tumor growth, metastasis, and vascularization. Herein, we show that NODAL expression correlates with the presence of activated fibroblasts in human triple-negative breast cancers and that it directly induces Cancer-associated fibroblasts phenotypes. We further show that NODAL reprograms cancer cell secretomes by simultaneously altering levels of chemokines (e.g., CXCL1), cytokines (e.g., IL-6) and growth factors (e.g., PDGFRA), leading to alterations in MSC chemotaxis. We therefore demonstrate a hitherto unappreciated mechanism underlying the dynamic regulation of the TME.

Sequential combination of bortezomib and WEE1 inhibitor, MK-1775, induced apoptosis in multiple myeloma cell lines.

INTRODUCTION: Multiple myeloma (MM) remains incurable due to high rates of relapse after various treatment regimens. WEE1 is a cell cycle related gene that regulates the G2/M checkpoint and promotes cell cycle suspension for consequent DNA repair. To date, there are clinical studies for the evaluation of WEE1 inhibitors in the treatment of solid tumors and studies on cell lines of non-MM hematological tumors. OBJECTIVES: To perform in vitro functional studies to verify the effect of the inhibition of WEE1 on MM cell lines viability and its potential as therapeutic target. MATERIAL AND METHODS: WEE1 expression was evaluated in 22 newly diagnosed MM patients and in four MM cell lines, RPMI-8226, U266 and SKO-007 and SK-MM2, by quantitative real-time PCR (qPCR). After treatment with the WEE1 inhibitor (MK-1775), with or without proteasome inhibitor (bortezomib) pretreatment, we assessed cell viability through Prestoblue functional test, microspheres formation in soft agar, and induction of apoptosis and cell cycle alterations by flow cytometry. RESULTS: All MM cell lines showed WEE1 expression by qPCR. RPMI-8226 and U266 showed a 50% reduction in cell viability after 24 h of incubation with MK-1775, at concentrations of 5 µM and 20 µM, respectively. SKO-007 showed dose and time dependence to this drug. Combination therapy with bortezomib and MK-1775 abolished the formation of soft agar microspheres in the RPMI-8226 cell line (also responsive to the use of both drugs) and U266, but SKO-007 was resistant to all drugs, isolated and combined. However, treatment of bortezomib followed by MK-1775 (sequential treatment) versus bortezomib alone showed statistically significant impact on cell lines total apoptosis: 88.8% vs 74.1% in RPMI-8222 (confirmed by cell cycle experiments); 92.5% vs 86.6% in U266; and 60.2% 30.9% on SKO-007 (p < 0.05). CONCLUSION: The sequential combination of bortezomib and WEE1 inhibitor, MK-1775, induced apoptosis in RPMI-8226, U266, and especially SKO-007 cell lines, more efficiently than the use of the same isolated drugs, highlighting its effect in inhibition of proliferation of tumor cells in MM cell lines. Our data suggest that WEE1 can figure as a MM target and that the sequential combination of bortezomib and MK-1775 may be explored in future clinical trials.

Exploring major signaling cascades in melanomagenesis: a rationale route for targetted skin cancer therapy.

Although most melanoma cases may be treated by surgical intervention upon early diagnosis, a significant portion of patients can still be refractory, presenting low survival rates within 5 years after the discovery of the illness. As a hallmark, melanomas are highly prone to evolve into metastatic sites. Moreover, melanoma tumors are highly resistant to most available drug therapies and their incidence have increased over the years, therefore leading to public health concerns about the development of novel therapies. Therefore, researches are getting deeper in unveiling the mechanisms by which melanoma initiation can be triggered and sustained. In this context, important progress has been achieved regarding the roles and the impact of cellular signaling pathways in melanoma. This knowledge has provided tools for the development of therapies based on the intervention of signal(s) promoted by these cascades. In this review, we summarize the importance of major signaling pathways (mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K)-Akt, Wnt, nuclear factor κ-light-chain-enhancer of activated B cell (NF-κB), Janus kinase (JAK)-signal transducer and activator of transcription (STAT), transforming growth factor ß (TGF-ß) and Notch) in skin homeostasis and melanoma progression. Available and developing melanoma therapies interfering with these signaling cascades are further discussed.