Antiproliferative Functions Research Articles

The Anti-proliferative Activity of GnRH Through Downregulation of the Akt/ERK Pathways in Pancreatic Cancer.

Gonadotropin-releasing hormone (GnRH) has been demonstrated to exert anti-proliferative functions on various tumor cells in endometrial, ovarian, bladder, or prostate cancer as a part of the autocrine system. In addition, the expression levels of GnRH and its receptor had been identified in breast cancer or non-reproductive cancers, such as glioblastoma and pancreatic cancer. Previous studies have reported abnormal GnRH expression in several malignant tumors, suggesting that GnRH and its receptor might be essential for tumourigenesis. In the present study, we attempted to clarify the mechanisms underlying GnRH function in cell proliferation in pancreatic cancer. Our results indicated that GnRH expression might be essential for the malignancy of pancreatic cancer. We then found that GnRH overexpression can induce cell apoptosis through activating the Bcl-2/Bax pathway and autophagy might be involved in the GnRH-mediated apoptosis in Panc1 cells. Further investigation showed that the inhibition of GnRH may promote tumor invasion and migration through upregulation of MMP2 expression in pancreatic cancer cells. Moreover, our results indicated that GnRH can regulate the Akt/ERK1/2 pathways to promote cell proliferation by inhibiting cell apoptosis in Panc1 cells. Therefore, our finding exhibited that the regulation of GnRH expression may be essential for tumourigenesis in pancreatic cancer, and might be a potential target for the treatment of the patients with pancreatic cancer.

Phycocyanin Exerts Anti-Proliferative Effects through Down-Regulating TIRAP/NF-κB Activity in Human Non-Small Cell Lung Cancer Cells.

Phycocyanin is a type of marine functional food additive, exerting a health care efficacy with no side effects. It has been shown that phycocyanin possesses anticancer function in non-small cell lung cancer (NSCLC) cells, but the underlying regulatory mechanism still remains unclear. Further investigation on the antineoplastic mechanism of phycocyanin would provide useful information on NSCLC treatment. In this study, we explored the in vitro function and mechanism of phycocyanin in three typical NSCLC cell lines, H1975, H1650, and LTEP-a2, for the first time. Phenotypic experiments showed that phycocyanin significantly induced the apoptosis as well as suppressed the growth of NSCLC cells. Transcriptome analysis suggested that toll/interleukin 1 receptor domain-containing adaptor protein (TIRAP) was significantly down-regulated by phycocyanin. Strikingly, similar to phycocyanin-treated assays, siRNA knockdown of TIRAP expression also resulted in the anti-proliferative phenomenon in NSCLC cells. In addition, the activity of NF-κB signaling was also suppressed after silencing TIRAP expression, revealing that phycocyanin exerted anti-proliferative function through down-regulating TIRAP/NF-κB activity in NSCLC cells. Collectively, this study has laid a theoretical basis on the treatment of NSCLC and the potential utilization of marine functional products.

Long non-coding RNA miR143HG predicts good prognosis and inhibits tumor multiplication and metastasis by suppressing mitogen-activated protein kinase and Wnt signaling pathways in hepatocellular carcinoma.

The expression of microRNA143HG (miR143HG) was significantly downregulated in hepatocellular carcinoma (HCC) tissues by bioinformatics analysis. This study aimed to determine the role of miR143HG in HCC cell proliferation and metastasis. Fifty patients with HCC were divided into two groups based on median miR143HG expression levels. The correlation between miR143HG expression and prognosis, and the correlations between miR143HG expression and the patients' clinicopathological characteristics were evaluated based on the two groups. Gain-of-function and loss-of-function measurements of miR143HG were carried out to verify the biological function of miR143HG by Cell Counting Kit-8, EdU, Transwell, and western blotting assays and flow cytometric analysis. The underlying mechanism was explored by quantitative real-time polymerase chain reaction of miRNA (miR-155-5p and miR-26b-5p), luciferase reporter assay, western blotting of Wnt signaling pathway-related proteins (β-catenin, adenomatous polyposis coli (APC), glycogen synthase kinase 3β (GSK3β), ZEB1, and E-cadherin), mitogen-activated protein kinase (MAPK) signaling pathway-related proteins (extracellular signal-regulated kinase [ERK]1/2, p-ERK1/2, c-Jun N-terminal kinase (JNK), p-JNK, P38, and p-P38), and immunofluorescence staining of β-catenin. miR143HG expression was markedly downregulated in HCC tissues and cells. Its expression was associated with the presence or absence of portal vein tumor thrombus, hepatitis B virus infection, relapse and metastasis, and Barcelona Clinic Liver Cancer stage. Additionally, miR143HG expression predicted a good prognosis and acted as an independent prognostic factor in HCC for overall survival. Overexpression of miR143HG suppressed HCC cell proliferation and metastasis, and induced cell cycle arrest and apoptosis. Consistently, the depletion of miR143HG resulted in the opposite phenomenon of the aforementioned results. miR143HG inhibits miR-155 expression; miR-155 directly targets APC, which is a negative regulator of the Wnt/β-catenin pathway, so miR143HG can act on the Wnt pathway. miR143HG was further found to reduce the expression of β-catenin and block the nuclear accumulation of β-catenin, ultimately inhibiting the activation of the Wnt pathway. It inhibits the expression of Wnt downstream target gene ZEB1, and then E-cadherin expression is increased and cell motility is inhibited. Furthermore, miR143HG exerts its antiproliferative function by influencing the MAPK signaling pathway and then inducing G2 /M arrest in cells. This study showed that miR143HG plays critical roles in the development and progression of HCC by suppressing the MAPK and Wnt signaling pathways.

Gastrodin attenuates proliferation and inflammatory responses in activated microglia through Wnt/β-catenin signaling pathway

Microglia contribute to the regulation of neuroinflammation and play an important role in the pathogenesis of brain disorders. Thus, regulation of neuroinflammation triggered by activation of microglia has become a promising therapeutic strategy. Here, we investigated the beneficial effects of Gastrodin in activated microglia and analyzed the underlying molecular mechanisms. Microglia activation was regulated by Gastrodin not only in terms of microglia population size but also production of inflammatory mediators. Gastrodin inhibited the expression of inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α), cyclin-D1 and Ki67 in lipopolysaccharide (LPS)-stimulated BV-2 or primary microglia. Gastrodin also suppressed the expression of iNOS and Ki67 in activated microglia in three-day-old LPS-injected postnatal rats. In addition, the present results have shown that Gastrodin inhibited LPS-induced phosphorylation of glycogen synthase kinase-3β (GSK-3β) at Ser 9 and β-catenin activity. We further extended our investigation to determine whether Wnt/β-catenin signaling pathway was involved in the anti-inflammatory and anti-proliferation function of Gastrodin. β-Catenin antagonist (XAV939) was used to block LPS-mediated upregulation of iNOS, TNF-α, cyclin-D1, nitric oxide (NO) and the number of cells in the G2/M+S phase of cell cycle. Moreover, treatment with LiCl, a special Wnt/β-catenin pathway agonist significantly blocked Gastrodin-mediated down-regulation of iNOS, TNF-α, cyclin-D1, NO and the number of cells in the G2/M+S phase of cell cycle in LPS-stimulated BV-2 microglia. Taken together, the present results suggested that Gastrodin mediated anti-inflammatory and anti-proliferation effects in activated microglia by modulating the Wnt/β-catenin signaling pathway.

Calcitriol Inhibits the Proliferation of Triple-Negative Breast Cancer Cells through a Mechanism Involving the Proinflammatory Cytokines IL-1β and TNF-α.

Triple-negative breast cancer (TNBC) is one of the most aggressive tumors, with poor prognosis and high metastatic capacity. The aggressive behavior may involve inflammatory processes characterized by deregulation of molecules related to the immunological responses in which interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) are involved. It is known that calcitriol, the active vitamin D metabolite, modulates the synthesis of immunological mediators; however, its role in the regulation of IL-1β and TNF-α in TNBC has been scarcely studied. In the present study, we showed that TNBC cell lines SUM-229PE and HCC1806 expressed vitamin D, IL-1β, and TNF-α receptors. Moreover, calcitriol, its analogue EB1089, IL-1β, and TNF-α inhibited cell proliferation. In addition, we showed that synthesis of both IL-1β and TNF-α was stimulated by calcitriol and its analogue. Interestingly, the antiproliferative activity of calcitriol was significantly abrogated when the cells were treated with anti-IL-1β receptor 1 (IL-1R1) and anti-TNF-α receptor type 1 (TNFR1) antibodies. Furthermore, the combination of calcitriol with TNF-α resulted in a greater antiproliferative effect than either agent alone, in the two TNBC cell lines and an estrogen receptor-positive cell line. In summary, this study demonstrated that calcitriol exerted its antiproliferative effects in part by inducing the synthesis of IL-1β and TNF-α through IL-1R1 and TNFR1, respectively, in TNBC cells, highlighting immunomodulatory and antiproliferative functions of calcitriol in TNBC tumors.

Surface-Degradable Drug-Eluting Stent with Anticoagulation, Antiproliferation, and Endothelialization Functions.

Drug-eluting stents (DES) have been widely applied for saving the life of patients with coronary artery diseases (CADs). However, conventional polymers such as polylactic acid (PLA) and poly (lactic-co-glycolic acid) (PLGA), which are widely applied for drug-eluting stents studies, have serious bulk erosion problems, like high local acidity and poor mechanical properties. Instead, we chose surface erosion polymer poly (1, 3-trimethylene carbonate) (PTMC) as a drug carrier in this study. Here, we fabricated and characterized a novel durable-polymer drug-eluting 316 L stainless steel (SS) stent, in which the inner surface was coated with a Ti–O film using the magnetron sputtering method to promote the growth of endothelial cells (ECs). On the outer layer of the stent, first, a Ti–O film was deposited and, then, on top of it a rapamycin-loaded PTMC coat was deposited using the ultrasonic atomization spray method. This dual coating inhibited the migration and expansion of smooth muscle cells (SMCs). The drug coating also inhibited the adhesion/activation of platelets. In tests on dogs, it was found the novel stent promoted re-endothelialization and reduced restenosis, in contrast to the plain SS stent. Thus, the novel stent may have promise for use in treating patients with CAD.

Oral and intrauterine progestogens for atypical endometrial hyperplasia.

Endometrialcarcinomaisthemostcommongynaecologicmalignancyintheworldanddevelopsthroughpreliminarystagesofendometrialhyperplasia. Atypicalendometrialhyperplasiasuggestsasignificantpre-malignantstatewithfrankprogressiontoendometrialcarcinoma, and tends to occur at a young age. Oral progestins have been used as conservative treatment in young women with atypical endometrial hyperplasia, but they are associated with poor tolerability and side effects that may limit their overall efficacy. So it has become increasingly important and necessary to find a safe and effective fertility-sparing treatment with better tolerability and fewer side effects than the options currently available. Thelevonorgestrel-releasing intrauterinesystem (LNG-IUS) hasbeenusedto provide endometrial protection in women with breast cancer who are on adjuvant tamoxifen. The antiproliferative function of levonorgestrel is thought to reduce the risk of endometrial hyperplasia. Todeterminetheefficacyandsafetyoforal and intrauterine progestogens intreatingatypicalendometrialhyperplasia. In July 2018 we searched CENTRAL; MEDLINE; Embase; CINAHL, PsycINFO and the China National Knowledge Infrastructure for relevant trials. Cochrane Gynaecology and Fertility (CGF) Specialised Register and Embase were searched in November 2018. We attempted to identify trials from references in published studies. We also searched for ongoing trials in five major clinical trials registries. Randomised controlled trials (RCTs) of oral and intrauterine progestogens(LNG-IUS) versus each other or placebo in women with a confirmed histological diagnosis of simple or complex endometrial hyperplasia with atypia. Two review authors assessed trial eligibility and risk of bias and extracted the data. The primary outcomes of the review were rate of regression and adverse effects. Secondary outcomes included rate of recurrence and proportion of women undergoing hysterectomy. We have used GRADE methodology to judge the quality of the evidence. We included one RCT (153 women) comparing the LNG-IUS administering 20 micrograms (μu) levonorgestrel per day versus 10 milligrams of continuous or cyclical oral medroxyprogesterone (MPA) for treating any type of endometrial hyperplasia. Only 19 women in this study were histologically confirmed with atypical complex hyperplasia before treatment. The evidence was of low or very low quality. The included study was at low risk of bias, but the quality of the evidence was very seriously limited by imprecision and indirectness. We did not find any RCTS comparing the LNG-IUS or oral progestogens versus placebo in women with atypical endometrial hyperplasia.Among the 19 women with atypical complex hyperplasia, after six months of treatment there was insufficient evidence to determine whether there was a difference in regression rates between the LNG-IUS group and the progesterone group (odds ratio (OR) 2.76, 95% confidence interval (CI) 0.26 to 29.73; 1 RCT subgroup, 19 women, very low-quality evidence). The rate of regression was 100% in the LNG-IUS group (n = 6/6) and 77% in the progesterone group (n = 10/13).Among the total study population (N = 153), over the six months' treatment the main adverse effects were nausea and vaginal bleeding. There was no evidence of a difference between the groups in rates of nausea (OR 0.58, 95% CI 0.28 to 1.18; 1 RCT, 153 women, very low-quality evidence). Vaginal bleeding was more common in the LNG-IUS group (OR 2.89, 95% CI 1.11 to 7.52; 1 RCT, 153 women, low-quality evidence). Except for nausea and vaginal bleeding, no other adverse effects were reported. We did not find any RCTS of women with atypical endometrial hyperplasia, and our findings derive from a subgroup of 19 women in a larger RCT. All six women who used the LNG-IUS system achieved regression of atypical hyperplasia, but there was insufficient evidence to draw any conclusions regarding the relative efficacy of LNG-IUS versus oral progesterone (MPA) in this group of women. When assessed in a population of women with any type of endometrial hyperplasia, there was no clear evidence of a difference between LNG-IUS and oral progesterone (MPA) in risk of nausea, but vaginal bleeding was more likely to occur in women using the LNG-IUS. Larger studies are necessary to assess the efficacy and safety of oral and intrauterine progestogens in treating atypical endometrial hyperplasia.

Identification of four type I IFNs from Japanese eel with differential expression properties and Mx promoter inducibility

Type I IFNs are a family of cytokines with antiviral, anti-proliferative and immune-modulatory functions. In this study, four type I IFNs (termed AjIFN1-4) have been cloned from the Japanese eel, Anguilla japonica. The open reading frames of AjIFN1-4 are 552, 534, 546 and 561 bp in length, encoding 183, 177, 181, and 186 amino acids (aa), respectively. Sequence comparison and phylogenetic analysis results revealed that AjIFN1 and AjIFN2 belong to group one (2C-containing) IFNs, while AjIFN3 and AjIFN4 belong to group two (4C-containing) IFNs. Syntenic comparison showed that chromosome block duplication and rearrangement events might have occurred at IFN loci in different teleost lineages. Expression analysis revealed the rapid induction of AjIFNl and AjIFN2 in response to poly I:C stimulation, while AjIFN3 and AjIFN4 were predominantly expressed at later time points. Two Mx promoter reporter assays were conducted to assess the Mx-inducing capability of AjIFN1-4. It is shown that the overexpression of AjIFN1-4 all promoted the luciferase activity of MxB reporter, but the activity of MxC reporter increased only in cells transfected with AjIFN1. Collectively, it is suggested that teleost IFNs were evolved independently in different lineages of fish and may function differently in teleost antiviral immunity.

Anticancer effects of echinacoside in hepatocellular carcinoma mouse model and HepG2 cells.

Echinacoside (ECH)is a phenylethanoid glycoside extracted from a Chinese herbal medicine, Cistanches salsa. ECH possesses many biological properties, including anti-inflammation, neural protection, liver protection, and antitumor. In the current study, we aimed to explore the effects of ECH on hepatocellular carcinoma (HCC) and the underlying mechanisms. The results showed that ECH could attenuate diethylnitrosamine (DEN)-induced HCC in mice, and exerted antiproliferative and proapoptotic functions on HepG2 HCC cell line. ECH exposure in HepG2 cells dose-dependently reduced the phosphorylation of AKT (p-AKT) and enhanced the expression of p21 (a cell cycle inhibitor) and Bax (a proapoptotic protein). Furthermore, ECH significantly suppressed insulin-like growth factor-1-induced p-AKT and cell proliferation. These data indicated that phosphoinositide 3-kinase (PI3K)/AKT signaling was involved in the anti-HCC activity of ECH. Gene set enrichment analysis results revealed a positive correlation between the PI3K pathway and triggering receptors expressed on myeloid cells 2 (TREM2) expression in HCC tissues. ECH exposure significantly decreased TREM2 protein levels in HepG2 cells and DEN-induced HCC. Furthermore, ECH-mediated proliferation inhibition and AKT signaling inactivation were notably attenuated by TREM2 overexpression. In conclusion, ECH exerted its antitumor activity via decreasing TREM2 expression and PI3K/AKT signaling.

Design, Synthesis, Biological Activity, and Structural Analysis of Lactam‐Constrained PTPRJ Agonist Peptides

PTPRJ is a receptor-like protein tyrosine phosphatase mainly known for its antiproliferative and tumor-suppressive functions. PTPRJ dephosphorylates several growth factors and their receptors, negatively regulating cell proliferation and migration. We recently identified a disulfide-bridged nonapeptide, named PTPRJ-19 (H-[Cys-His-His-Asn-Leu-Thr-His-Ala-Cys]-OH), which activates PTPRJ, thereby causing cell growth inhibition and apoptosis of both cancer and endothelial cells. With the aim of replacing the disulfide bridge by a chemically more stable moiety, we have synthesized and tested a series of lactam analogues of PTPRJ-19. This replacement led to analogues with higher activity and greater stability than the parent peptide.

Abstract 161: Adult myogenic stem cells inhibit prostate cancer cell proliferation and increase docetaxel-mediated cell toxicity

Abstract Current treatments for prostate cancer (PCa) are primarily based on use of anti-androgen agents to prevent disease progression and bone lesions. However, metastatic PCa (mPCa) continues to progress in an androgen-independent manner, and consequently, bone and muscle tissues deteriorate, often resulting in severe pain and fragility. Adult stem cells have been used in regenerative medicine approaches for many years for treating human diseases through gene therapy. We have demonstrated for nearly two decades that a population of slow-adhering myogenic progenitor cells, called muscle progenitor cells (MPCs), has tremendous ability to regenerate bone, skeletal muscle, cartilage, nerve, and cardiac muscle after injury. However, to date, the potential therapeutic use of MPCs in cancers has not yet been investigated. We hypothesized that MPCs can inhibit proliferation and survival of PCa cells and increase docetaxel-induced cytotoxicity of the PCa cells. Moreover, MPCs may be effective in decreasing PCa-induced skeletal lesions and promote bone and muscle tissue repair. The objective of this study was to evaluate the paracrine roles of secreted factors from MPCs with respect to proliferation and survival of PCa cells. Here we showed that co-culture of PC3 and C42B cells with MPCs in transwell inserts strongly decreased PCa cell proliferation and survival by activating CDK inhibitors (p16 and p27) and apoptotic BBC3 and NOXA genes. Analysis of factors secreted by MPCs using ELISA protein array and mass spectrometry identified several proteins with known antiproliferative functions, including IGFBP6/7, pigment epithelium-derived factor, HPCAL1, NO, and SPARC. Additionally, conditioned media (CM) from MPCs increased the docetaxel-induced cytotoxicity of both androgen-dependent and -independent PCa cells. Molecular analysis also showed decreased expression of AR, MLL, FOXA1, TWF1, and TGIF1, which are known oncogenic regulators of PCa progression. Since metastatic PCa causes both osteolytic and osteoblastic lesions through the secretion of RANKL and BMPs, respectively, we then showed that treatment of PCa cells with OPG and noggin, antagonists of RANKL and BMPs, respectively, inhibited their cell proliferation. Further, CM from PCa cells pretreated with noggin and OPG resulted in decreased osteoblast activity in primary osteoblasts and decreased osteoclast activity in macrophage cells, respectively, when compared to CM from untreated PCa cells. These results suggest that noggin and OPG could be used as therapeutic proteins for reducing PCa-induced skeletal lesions through MPC gene delivery. Taken together, our data suggest that use of adult stem cell-based therapy along with current chemotherapy agents (e.g., docetaxel) is a promising effective strategy for treatment of PCa and preventing metastatic skeletal lesions. Citation Format: Krishna M. Sinha, Rozita Yarmand, Reid Andrew, Johnny Huard. Adult myogenic stem cells inhibit prostate cancer cell proliferation and increase docetaxel-mediated cell toxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 161.

Abstract 5367: Elucidating the factors determining P53 binding and transcriptomic response to DNA damage

Abstract Mutations in tp53 are thought to be one of the most common mechanisms by which cancer cells evade tumor suppression. Yet the exact mechanism of tumor suppression by P53 remains to be fully understood. The transcription factor P53 is activated in response to oncogenic stresses and exerts distinct anti-proliferative functions based on the stressor and cell type. Although numerous mammalian ChIP-Seq studies have identified thousands of P53 binding sites, the functionality of these binding sites remains to be established. To study how P53 binding following DNA damage differs between cell types, we performed comparisons between P53 ChIP-Seq data from Drosophila embryos at different developmental stages and a Drosophila cell line (Kc167). Differential expression analysis using RNA-Seq indicated that at an early stem cell-like developmental stage of Drosophila embryos there is P53-dependent induction of pro-apoptotic genes in response to irradiation but not in the later differentiated stages. We aim to establish functionally significant P53 binding sites by combining ChIP-Seq and RNA-Seq data from Drosophila embryos as well as Kc167. The functional significance of these binding sites will be identified by CRISPR-Cas9–mediated genome editing. Preliminary genome-wide motif analysis studies also exhibited that homotypic clustering of P53 consensus motifs is associated with P53 binding. We will also perform comparison studies of DNA damage-induced P53 binding in humans, mice and flies to identify analogous patterns. Preliminary studies revealed that a majority of the P53 binding sites are located at the repetitive regions of the Drosophila genome, especially the Long terminal repeats (LTRs) and Long interspersed nuclear elements (LINEs) as seen previously in mammals by other groups including Botcheva et al and Chang et al. P53 has been known to regulate the expression of retrotransposons and maintain genetic stability by keeping the number of repeats in control. We further aim to see if the functions carried out by P53 differ between repetitive vs. non-repetitive binding regions in Drosophila. This comparative genomics study will help identify the functionally significant P53 binding sites thus further our understanding of tumor suppression by P53. The knowledge obtained from this study will also be valuable in devising novel strategies to restore P53 function in cancers. Citation Format: Varsha Sundaresan, Ying Li, Benedetto DiCiaccio, Victor T. Lin, Adrian A. Acuna Higaki, Nicole F. Pelletier, Jessica T. Cheung, Lei Zhou. Elucidating the factors determining P53 binding and transcriptomic response to DNA damage [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5367.

SALL2 represses cyclins D1 and E1 expression and restrains G1/S cell cycle transition and cancer-related phenotypes.

SALL2 is a poorly characterized transcription factor that belongs to the Spalt‐like family involved in development. Mutations on SALL2 have been associated with ocular coloboma and cancer. In cancers, SALL2 is deregulated and is proposed as a tumor suppressor in ovarian cancer. SALL2 has been implicated in stemness, cell death, proliferation, and quiescence. However, mechanisms underlying roles of SALL2 related to cancer remain largely unknown. Here, we investigated the role of SALL2 in cell proliferation using mouse embryo fibroblasts (MEFs) derived from Sall2 −/− mice. Compared to Sall2 +/+ MEFs, Sall2 −/− MEFs exhibit enhanced cell proliferation and faster postmitotic progression through G1 and S phases. Accordingly, Sall2 −/− MEFs exhibit higher mRNA and protein levels of cyclins D1 and E1. Chromatin immunoprecipitation and promoter reporter assays showed that SALL2 binds and represses CCND1 and CCNE1 promoters, identifying a novel mechanism by which SALL2 may control cell cycle. In addition, the analysis of tissues from Sall2 +/+ and Sall2 −/− mice confirmed the inverse correlation between expression of SALL2 and G1‐S cyclins. Consistent with an antiproliferative function of SALL2, immortalized Sall2 −/− MEFs showed enhanced growth rate, foci formation, and anchorage‐independent growth, confirming tumor suppressor properties for SALL2. Finally, cancer data analyses show negative correlations between SALL2 and G1‐S cyclins’ mRNA levels in several cancers. Altogether, our results demonstrated that SALL2 is a negative regulator of cell proliferation, an effect mediated in part by repression of G1‐S cyclins’ expression. Our results have implications for the understanding and significance of SALL2 role under physiological and pathological conditions.

Aloperine executes antitumor effects through the induction of apoptosis and cell cycle arrest in prostate cancer in vitro and in vivo.

BackgroundProstate cancer (PCa) is one of the most common malignant diseases among male patients. Although androgen deprivation therapy remains the main treatment for PCa, most patients would inevitably progress to castration-resistant PCa, which is the main cause of cancer-related deaths. Thus, novel antitumor agents are urgently needed. Recent studies demonstrated that aloperine (ALO) as a natural alkaloid showed antitumor effects in other cancer types. However, the biological function and underlying mechanisms of ALO in PCa have not been investigated.MethodsPCa cell lines including LNCaP, PC3 and DU145 were cultured and treated with ALO. Cell Counting Kit-8 assay, colony formation assay, apoptosis assay and cell cycle assay were conducted to assess the biological role of ALO. In addition, a PCa subcutaneous xenograft mouse model was established to evaluate the role of ALO in terms of proliferation and apoptosis in vivo. We further measured the protein expression levels of p-Akt/Akt, p-ERK/ERK, c-Myc, cleaved caspase 3, p21, p53, Bcl-2 and Bax using the Western blot 48 h after ALO treatment of PCa cells.ResultsALO effectively inhibited the cell viability of PCa by inducing cell cycle arrest via the activation of the p53/p21 pathway and triggering apoptosis in vitro and in vivo. ALO also inhibited phosphorylation of Akt and ERK protein kinases and activated cleaved caspase 3 while exerting antiproliferation function through inducing apoptosis and cell cycle arrest in PCa cells.ConclusionBased on our findings, we conclude that ALO could suppress the tumor growth and promote cell apoptosis and cell cycle arrest in PCa cells, which indicated that ALO could act as a novel therapeutic agent in treatment of human PCa.

Aberrant Caveolin-1-Mediated Smad Signaling and Proliferation Identified by Analysis of Adenine 474 Deletion Mutation (c.474delA) in Patient Fibroblasts: A New Perspective in the Mechanism of Pulmonary Hypertension.

A heterozygous Caveolin-1 c.474delA mutation has been identified in a family with heritable pulmonary arterial hypertension (PAH). This frameshift mutation leads to caveolin-1 protein that contains all known functional domains but has a change only in the final 20 amino acids of the C terminus. Here we studied how this mutation alters caveolin-1 function using patient-derived fibroblasts. Transmission electron microscopy showed that fibroblasts carrying the c.474delA mutation formed typical caveolae. Expression of mutated caveolin-1 in caveolin-1-null mouse fibroblasts failed to induce formation of caveolae due to retention of the mutated protein in the endoplasmic reticulum. However, co-expression of wild type caveolin-1 with mutated caveolin-1 restored the ability to form caveolae. Importantly, fibroblasts carrying the mutation showed 2-fold increase in proliferation rate associated with hyper-phosphorylation of Smad1/5/8. This mutation impaired the anti-proliferative function of caveolin-1. Inhibition of type I TGFβ receptors ALK1/2/3/6 responsible for phosphorylation of Smad1/5/8 reduced the hyper-proliferation seen in c.474delA fibroblasts. These results demonstrate the critical role of the final 20 amino acids of caveolin-1 in modulating fibroblast proliferation through dampening Smad signaling, and suggest that augmented Smad signaling and fibroblast hyper-proliferation are contributing factors in the pathogenesis of PAH in patients with caveolin-1 c.474delA mutation.

Scoulerine affects microtubule structure, inhibits proliferation, arrests cell cycle and thus culminates in the apoptotic death of cancer cells

Scoulerine is an isoquinoline alkaloid, which indicated promising suppression of cancer cells growth. However, the mode of action (MOA) remained unclear. Cytotoxic and antiproliferative properties were determined in this study. Scoulerine reduces the mitochondrial dehydrogenases activity of the evaluated leukemic cells with IC50 values ranging from 2.7 to 6.5 µM. The xCELLigence system revealed that scoulerine exerted potent antiproliferative activity in lung, ovarian and breast carcinoma cell lines. Jurkat and MOLT-4 leukemic cells treated with scoulerine were decreased in proliferation and viability. Scoulerine acted to inhibit proliferation through inducing G2 or M-phase cell cycle arrest, which correlates well with the observed breakdown of the microtubule network, increased Chk1 Ser345, Chk2 Thr68 and mitotic H3 Ser10 phosphorylation. Scoulerine was able to activate apoptosis, as determined by p53 upregulation, increase caspase activity, Annexin V and TUNEL labeling. Results highlight the potent antiproliferative and proapoptotic function of scoulerine in cancer cells caused by its ability to interfere with the microtubule elements of the cytoskeleton, checkpoint kinase signaling and p53 proteins. This is the first study of the mechanism of scoulerine at cellular and molecular level. Scoulerine is a potent antimitotic compound and that it merits further investigation as an anticancer drug.

Defining the distinct, intrinsic properties of the novel type I interferon, IFNϵ

The type I interferons (IFNs) are a family of cytokines with diverse biological activities, including antiviral, antiproliferative, and immunoregulatory functions. The discovery of the hormonally regulated, constitutively expressed IFNϵ has suggested a function for IFNs in reproductive tract homeostasis and protection from infections, but its intrinsic activities are untested. We report here the expression, purification, and functional characterization of murine IFNϵ (mIFNϵ). Recombinant mIFNϵ (rmIFNϵ) exhibited an α-helical fold characteristic of type I IFNs and bound to IFNα/β receptor 1 (IFNAR1) and IFNAR2, but, unusually, it had a preference for IFNAR1. Nevertheless, rmIFNϵ induced typical type I IFN signaling activity, including STAT1 phosphorylation and activation of canonical type I IFN signaling reporters, demonstrating that it uses the JAK-STAT signaling pathway. We also found that rmIFNϵ induces the activation of T, B, and NK cells and exhibits antiviral, antiproliferative, and antibacterial activities typical of type I IFNs, albeit with 100-1000-fold reduced potency compared with rmIFNα1 and rmIFNβ. Surprisingly, although the type I IFNs generally do not display cross-species activities, rmIFNϵ exhibited high antiviral activity on human cells, suppressing HIV replication and inducing the expression of known HIV restriction factors in human lymphocytes. Our findings define the intrinsic properties of murine IFNϵ, indicating that it distinctly interacts with IFNAR and elicits pathogen-suppressing activity with a potency enabling host defense but with limited toxicity, appropriate for a protein expressed constitutively in a sensitive mucosal site, such as the reproductive tract.

The inhibitory effect of Cordycepin on the proliferation of cisplatin-resistant A549 lung cancer cells

The goal of this study is to determine the anti-cancer mechanism of Cordycepin in A549 Cisplatin-Resistance (CR) lung cancer cells. Cordycepin inhibited the viability of A549CR cells in a dose-dependent manner. The cell inhibition was due to induction of apoptosis in the cells treated with Cordycepin by activation of caspase −3, −8 and −9 activities. The cell cycle analysis showed that accumulation of Sub G1 was observed in Cordycepin-treated with A549CR lung cancer cells. Based on the data of expression profile analysis of cell signaling proteins using IPS-FPAA, H-Ras was down-regulated in Cordycepin-treated A549CR cells. Collectively, anti-proliferative function of Cordycepin was due to stimulation of the cell apoptosis and the cell cycle arrest via caspases activation and down-regulation of H-Ras.

Physicochemical Characterization and Functional Analysis of the Polysaccharide from the Edible Microalga Nostoc sphaeroides.

Nostoc colonies have been used as food and medicine for centuries, and their main supporting matrix is polysaccharides, which help Nostoc cells resist various environmental stresses including oxidative stress. Here we isolated a polysaccharide, nostoglycan, from cultured Nostoc sphaeroides colonies and determined its physicochemical properties, which revealed a characteristic infrared absorption spectrum typical of polysaccharides and an amorphous morphology with rough surfaces. We also show that nostoglycan has strong moisture absorption and retention capacities and a high relative viscosity. Using Caenorhabditis elegans models, we then demonstrate that nostoglycan is capable of improving overall survival rate of the animals under increased oxidative stress caused by paraquat. Nostoglycan also reduces reactive oxygen species level, inhibits protein carbonyl formation and lipid peroxidation, and increases activities of superoxide dismutase and catalase in paraquat-exposed nematodes. As oxidative stress may drive tumor progression, we further demonstrate that nostoglycan can suppress the proliferation of several types of tumor cells and induce apoptosis of human lung adenocarcinoma A549 cells via caspase-3 activation. Together, our results yield important information on the physicochemical characteristics and demonstrate the antioxidant and anti-proliferative functions of nostoglycan, and thus provide an insight into its potential in food and health industries.

P38 differentially regulates ERK, p21, and mitogenic signalling in two pancreatic carcinoma cell lines.

Whereas the p38 MAP kinase has largely been associated with anti-proliferative functions, several observations have indicated that it may also have positive effects on proliferation. In hepatocytes, we have found that p38 has opposing effects on DNA synthesis when activated by EGF and HGF. Here we have studied the function of p38 in EGF- and HGF-induced DNA synthesis in the two pancreatic carcinoma cell lines AsPC-1 and Panc-1. In Panc-1 cells, the MEK inhibitor PD98059 reduced EGF- and HGF-induced DNA synthesis, while the p38 inhibitor SB203580 strongly increased the basal DNA synthesis and reduced expression of the cyclin-dependent kinase inhibitor (CDKI) p21. In contrast, in AsPC-1 cells, EGF- and HGF-induced DNA synthesis was not significantly reduced by PD98059 but was inhibited by SB203580. Treatment with SB203580 amplified the sustained ERK phosphorylation induced by these growth factors and caused a marked upregulation of the expression of p21, which could be blocked by PD98059. These results suggest that while DNA synthesis in Panc-1 cells is enhanced by ERK and strongly suppressed by p38, in AsPC-1 cells, p38 exerts a pro-mitogenic effect through MEK/ERK-dependent downregulation of p21. Thus, p38 may have suppressive or stimulatory effects on proliferation depending on the cell type, due to differential cross-talk between the p38 and MEK/ERK pathways.