Pancreatic cancer is one of the most aggressive solid malignancies prone to metastasis. Epithelial-mesenchymal transition (EMT) contributes to cancer invasiveness and drug resistance. In this study, we investigated whether HS-173, a novel PI3K inhibitor blocked the process of EMT in pancreatic cancer. HS-173 inhibited the growth of pancreatic cancer cells in a dose- and time-dependent manner. Moreover, it significantly suppressed the TGF-β-induced migration and invasion, as well as reversed TGF-β-induced mesenchymal cell morphology. Also, HS-173 reduced EMT by increasing epithelial markers and decreasing the mesenchymal markers by blocking the PI3K/AKT/mTOR and Smad2/3 signaling pathways in pancreatic cancer cells. In addition, HS-173 clearly suppressed tumor growth without drug toxicity in both xenograft and orthotopic mouse models. Furthermore, to explore the anti-metastatic effect of HS-173, we established pancreatic cancer metastatic mouse models and found that it significantly inhibited metastatic dissemination of the primary tumor to liver and lung. Taken together, our findings demonstrate that HS-173 can efficiently suppress EMT and metastasis by inhibiting PI3K/AKT/mTOR and Smad2/3 signaling pathways, suggesting it can be a potential candidate for the treatment of advanced stage pancreatic cancer.

Background/Aims: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignant tumors with poor prognosis. Conventional chemotherapies including gemcitabine have failed owing to weak response and side effects. Hence novel treatment regimens are urgently needed to improve the therapeutic efficacy. In this study, we aimed to assess the anticancer activity of melatonin and sorafenib as a novel therapy against PDAC. Methods: We used various apoptosis assay and PDAC xenograft model to assess anticancer effect in vitro and in vivo. We applied phospho-receptor tyrosine kinase (RTK) array and phospho-tyrosine kinase array to explore the mechanism of the combined therapy. Western blotting, proximity ligation assay, and immunoprecipitation assay were also performed for validation. Results: Melatonin synergized with sorafenib to suppress the growth of PDAC both in vitro and in vivo. The effect was due to increased apoptosis rate of PDAC cells that was accompanied by mitochondria dysfunction. The enhanced anticancer efficacy by the co-treatment could be explained by blockade of PDGFR-β/STAT3 signaling pathway and melatonin receptor (MT)-mediated STAT3. Conclusions: Melatonin reinforces the anticancer activity of sorafenib by downregulation of PDGFR-β/STAT3 signaling pathway and melatonin receptor (MT)-mediated STAT3. The combination of the two agents might be a potential therapeutic strategy for treating PDAC.

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In cancer treatment, herbal medicines may be a good choice because of the reduced risk of adverse side effects. Artemisia capillaris has been recognized as a promising candidate due to its hepatoprotective effects. Herein, we investigated whether A. capillaris-derived fraction (ACE-63) could inhibit the progression of hepatocellular carcinoma (HCC) and its underlying mechanism. In this study, ACE-63 effectively inhibited the growth and proliferation of HCC cells. ACE-63 induced apoptosis, as observed using Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, which was accompanied with increases in cleaved Poly (ADP-ribose) polymerase (PARP) and caspase-3 in HCC cells. Additionally, the pro-apoptotic effect of ACE-63 was demonstrated by a decrease in the expression of the X-linked inhibitor of apoptosis protein (XIAP) and survivin via a loss of mitochondrial membrane potential. In an ex vivo model, ACE-63 significantly inhibited tumor cell growth and induced apoptosis by increasing the expression of cleaved caspase-3 and DNA fragmentation. In addition, ACE-63 decreased the expression of hypoxia-inducible factor-1α and vascular endothelial growth factor and inhibited tube formation of human umbilical vein endothelial cells. A mechanistic study revealed that ACE-63 effectively suppressed the PI3K/AKT/mTOR signaling pathways, which were observed as a target signaling by phosphokinase array. Taken together, our findings demonstrate that ACE-63 could not only efficiently induce apoptosis but also inhibit the growth/angiogenesis of human HCC cells by blocking the PI3K/AKT/mTOR signaling pathway, suggesting that ACE-63 may be a new chemotherapeutic candidate against HCC.

ObjectivesTreatment of both platinum resistant high grade (HG) and low‐grade (LG) ovarian cancer (OVCA) poses significant challenges as neither respond well to conventional chemotherapy leading to morbidity and mortality. Identification of novel agents that can overcome chemoresistance is therefore critical. Previously, we have demonstrated that OVCA has basal upregulated unfolded protein response (UPR) and that targeting cellular processes leading to further and persistent upregulation of UPR leads to cell death. ONC201 is an orally bioavailable Dopamine Receptor D2 inhibitor demonstrating anticancer activity and was found to induce UPR. Given its unique properties, we hypothesized that ONC201 would overcome platinum resistance in OVCA.MethodsCisplatin sensitive and resistant HG OVCA and two primary LG OVCA cell lines were studied. Cell viability was determined using MTT assay. Cell migration was studied using wound healing assay. Apoptosis and mitochondrial membrane potential were investigated using flow cytometry. Analysis of pathway inhibition was performed by Western Blot. mRNA expression of UPR related genes were measured by qPCR. In vivo studies were completed utilizing axillary xenograft models. Co‐testing with conventional chemotherapy was performed to study synergy.ResultsONC201 significantly inhibited cell viability and migration in a dose dependent manner with IC50’s from 1‐20 µM for both cisplatin sensitive and resistant HG and LG‐OVCA cell lines. ONC201 lead to upregulation of the pro‐apoptotic arm of the UPR, specifically ATF‐4/CHOP/ATF3 and increased the intrinsic apoptosispathway. The compensatory, pro‐survival PI3K/AKT/mTOR pathway was downregulated. In vivo, weekly dosing of single agent ONC201 decreased xenograft tumor size by ~50% compared to vehicle. ONC201 also demonstrated significant synergy with paclitaxel in a highly platinum resistant OVCA cell‐line (OV433).ConclusionsOur findings demonstrate that ONC201 can effectively overcome chemoresistance in OVCA cells by blocking pro‐survival pathways and inducing the apoptotic arm of the UPR. This is a promising, orallybioavailable therapeutic agent to consider in clinical trials for patients with both HG and LG OVCA.