Search

Simple Summary: Triple-negative breast cancer (TNBC) is an aggressive and intractable malignancy. Although a high-level expression of epidermal growth factor receptor (EGFR) is a distinct feature of TNBC, targeting EGFR has not been successful yet. Here, we described a combination of the EGFR inhibitor gefitinib and IκB kinase (IKK) inhibitor IKK16 (Gefitinib+IKK16) as a potential therapeutic approach to treat TNBC. The combination of these drugs resulted in reduced cell viability and survival in TNBC cells in vitro. Mechanistically, several components of PI3K/AKT/mTOR pathway were further downregulated by drug combination compared with single-agent treatments. Gene expression analysis revealed that several NF-κB/RELA targets were suppressed, and a couple of tumor suppressor genes were induced by the drug combination. Taken together, targeting IKK may potentiate EGFR inhibition in TNBC. Triple-negative breast cancer (TNBC) remains as an intractable malignancy with limited therapeutic targets. High expression of epidermal growth factor receptor (EGFR) has been associated with a poor prognosis of TNBC; however, EGFR targeting has failed with unfavorable clinical outcomes. Here, we performed a combinatorial screening of fifty-five protein kinase inhibitors with the EGFR inhibitor gefitinib in the TNBC cell line MDA-MB-231 and identified the IκB kinase (IKK) inhibitor IKK16 as a sensitizer of gefitinib. Cell viability and clonogenic survival assays were performed to evaluate the antiproliferative effects of the gefitinib and IKK16 (Gefitinib + IKK16) combination in TNBC cell lines. Western blot analyses were also performed to reveal the potential mode of action of this combination. In addition, next-generation sequencing (NGS) analysis was performed in Gefitinib+IKK16-treated cells. The Gefitinib+IKK16 treatment synergistically reduced cell viability and colony formation of TNBC cell lines such as HS578T, MDA-MB-231, and MDA-MB-468. This combination downregulated p-STAT3, p-AKT, p-mTOR, p-GSK3β, and p-RPS6. In addition, p-NF-κB and the total NF-κB were also regulated by this combination. Furthermore, NGS analysis revealed that NF-κB/RELA targets including CCL2, CXCL8, EDN1, IL-1β, IL-6, and SERPINE1 were further reduced and several potential tumor suppressors, such as FABP3, FADS2, FDFT1, SEMA6A, and PCK2, were synergistically induced by the Gefitinib-+IKK16 treatment. Taken together, we identified the IKK/NF-κB pathway as a potential target in combination of EGFR inhibition for treating TNBC. [ABSTRACT FROM AUTHOR]

Embelin (EB) is a benzoquinone derivative isolated from Embelia ribes Burm plant. Recent scientific evidence shows that EB induces apoptosis and inhibits migration and invasion in highly metastatic human breast cancer cells. However, the exact mechanisms of EB in tumor metastasis and invasion have not been fully elucidated. Here, we investigated the underlying mechanisms of antimetastatic activities of EB in breast cancer cells. The EB downregulated the chemokine receptor 4 (CXCR4) as well as matrix metalloproteinase (MMP)-9/2 expression and upregulated the tissue inhibitor of metalloproteinase 1 expression in MDA-MB-231 cells under noncytotoxic concentrations but not in MCF-7 cells. Additionally, EB inhibited the CXC motif chemokine ligand 12 induced invasion and migration activities of MDA-MB-231 cells. A detailed study of underlying mechanisms revealed that the regulation of the downregulation of CXCR4 was at the transcriptional level, as indicated by the downregulation of mRNA expression and suppression of nuclear factor-kappa B (NF-κB) activation. It further reduced the binding of NF-κB to the CXCR4 promoter. Besides, EB downregulated mesenchymal marker proteins (neural cadherin and vimentin) and concurrently upregulated epithelial markers (epithelial cadherin and occludin). Overall, these findings suggest that EB can abrogate breast cancer cell invasion and metastasis by suppression of CXCR4, MMP-9/2 expressions, and inhibition of epithelial-mesenchymal transition and thus may have a great potential to suppress metastasis of breast cancer. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Ginkgetin, a biflavone from Ginkgo biloba leaves, is known to exhibit antiinflammatory, antifungal, neuroprotective, and antitumor activities, but its precise mechanism of action has not been fully elucidated. Because the aberrant activation of STAT3 has been linked with regulation of inflammation, proliferation, invasion, and metastasis of tumors, we hypothesized that ginkgetin modulates the activation of STAT3 in tumor cells. We found that ginkgetin clearly suppressed constitutive phosphorylation of STAT3 through inhibition of the activation of upstream JAK1 and c-Src kinases and nuclear translocation of STAT3 on both A549 and FaDu cells. Treatment with sodium pervanadate reversed the ginkgetin-induced down-modulation of STAT3, thereby indicating a critical role for a PTP. We also found that ginkgetin strongly induced the expression of the SHP-1 and PTEN proteins and its mRNAs. Further, deletion of SHP-1 and PTEN genes by siRNA suppressed the induction of SHP-1 and PTEN, and reversed the inhibition of STAT3 activation. Ginkgetin induced apoptosis as characterized by an increased accumulation of cells in subG1 phase, positive Annexin V binding, loss of mitochondrial membrane potential, down-regulation of STAT3-regulated gene products, and cleavage of PARP. Overall, ginkgetin abrogates STAT3 signaling pathway through induction of SHP-1 and PTEN proteins, thus attenuating STAT3 phosphorylation and tumorigenesis. [ABSTRACT FROM AUTHOR]

Brassinin (BSN), a type of indole compound derived from cruciferous vegetables, has shown anti-cancer effects in cells and animals. Capsaicin (CAP), an alkaloid derived from the chilli pepper, is also of interest in for its reported efficacy against various malignancies. The objective of our study was to analyze the potential synergistic anti-tumor effects of BSN combined with CAP on prostate cancer PC-3 cells. After treatment with BSN and CAP at various concentrations, the synergistic cytotoxic effect of PC-3 cells was analyzed by MTT method, proliferation, apoptosis, mitochondrial membrane potential, colony formation, and Western blotting. Moreover, the inhibitory effects of BSN and CAP on the constitutive expressions of MMP-9/2, their enzymatic activities, cellular migration, and cell invasion were also investigated. The cytotoxicity was synergistically increased in combination compared with the single drug used; moreover, proliferation, apoptosis, mitochondrial membrane potential, and colony formation were significantly suppressed and anti-apoptotic-, proliferative-, and metastatic-related proteins were clearly abolished in the combination group. Besides, constitutive MMP-9/2 expression, their enzymatic activities, cell migration, and tumor cell invasion were inhibited, and TIMP-1 was up-regulated in the combination group in PC-3 cells. Our results indicate, for the first time, that BSN and CAP in combination exert synergistic anticancer effects in prostate carcinoma. [ABSTRACT FROM AUTHOR]

Natural medicinal plants are multi-targeted in nature and their anti-cancer activities are also complex and varied, thus requiring a more systematic analysis of their modes of action. Since the activation of signal transducer and activator of transcription 3 (STAT3) is often deregulated in non-small cell lung carcinoma (NSCLC) cells and tissue specimens, its negative regulation can form the basis for identification of targeted therapy. In this report, we analyzed the possible anti-cancer effects of ophiopogonin D (OP-D) and the underlying mechanisms by which OP-D exerts its actions in NSCLC. OP-D exhibited substantial suppressive activity on STAT3 signaling and this effect was found to be mediated via oxidative stress phenomena caused by disturbance in GSH/GSSG ratio. In addition, OP-D induced apoptosis, activated caspase mediated apoptotic cascade and decreased expression of various oncogenic genes. Consistently, OP-D treatment significantly reduced NSCLC tumor growth in preclinical mouse model with via decreasing levels of p-STAT3. OP-D was also found to attenuate the expression of STAT3-regulated anti-apoptosis, cell cycle regulator, and angiogenesis biomarkers. Our findings suggest that OP-D can induce apoptosis and exert anti-tumor effects by inhibition of STAT3 signaling pathways in NSCLC. [ABSTRACT FROM AUTHOR]

Colorectal cancer (CRC) remains a significant global health concern, and targeting inflammation has emerged as a promising approach for its prevention and treatment. Medicinal plants and phytochemicals have garnered attention for their potential efficacy against inflammation with minimal toxicity. Osmanthus fragrans var. aurantiacus Makino (O. fragrans) has a history of traditional use in Korea and China in treating various inflammation-related conditions, but its potential use for CRC has not been uncovered. This study aims to explore the potential anti-proliferative and pro-apoptotic properties of O. fragrans , focusing on its impact on CRC treatment. By investigating O. fragrans , we aim to uncover its anti-proliferative and apoptotic effects in human CRC cells, potentially paving the way for effective and well-tolerated therapeutic strategies for CRC patients. Ethanol (EtOH) extracts of O. fragrans leaf and flower, along with specific fractions (n -hexane, ethyl acetate (EtOAc), n -butanol, and the aqueous residue) were evaluated for their anti-proliferative effects in human CRC cells using MTT assays, and compared to normal colon cells. Mechanistic insights and chemical profiling were obtained through flow cytometry, colorimetric assays, western blotting, and molecular docking, and high-performance liquid chromatography (HPLC) system. Both flower and leaf EtOH extracts of O. fragrans exhibited significant anti-proliferative effects in human CRC cells, with the leaf extract demonstrating higher potency. The EtOAc fraction from the leaf extract displayed the strongest anti-CRC cell proliferative effects while no cytotoxic effects in normal colon cells. Chemical profiling of these fractions identified triterpenoids as significant components in the EtOAc fractions. The leaf EtOAc fraction caused cell cycle arrest and apoptosis, accompanied by elevating intracellular reactive oxygen species and mitochondrial dysfunction in CRC cells. Additionally, it inhibited NF-κB and ERK1/2 signaling, leading to reduced COX2 expression. Notably, two triterpenoids isolated from the leaf EtOAc fraction, maslinic acid and corosolic acid, displayed potent anti-cancer activity in CRC cells without affecting normal colon cells. Corosolic acid exhibited a strong binding affinity to COX2 and reduced its expression, supporting its role in the anti-inflammatory and anti-cancer effects. Our findings suggest that O. fragrans , particularly its triterpenoid-rich EtOAc fraction, holds promise as a novel therapeutic agent for CRC prevention and therapy. These results provide valuable insights into the potential application of O. fragrans and its bioactive compounds in combating CRC. [Display omitted] • Osmanthus fragrans var. aurantiacus (O. fragrans) inhibits proliferation of colorectal cancer (CRC) cells. • The leaf EtOAc fraction of O. fragrans promotes apoptosis in CRC cells by inducing mitochondrial dysfunction. • Triterpenoids from the leaf EtOAc fraction display strong anti-CRC cell proliferation activity with induction of apoptosis. • The leaf EtOAc fraction and triterpenoids exhibit anti-CRC cell proliferation effects by inhibiting NF-κB and COX2. • These results underscore the therapeutic potential of O. fragrans and its bioactive compounds against CRC. [ABSTRACT FROM AUTHOR]