Blockade Of Signaling Pathway Research Articles

Agrimonolide and Desmethylagrimonolide Induced HO-1 Expression in HepG2 Cells through Nrf2-Transduction and p38 Inactivation.

Agrimonolide and desmethylagrimonolide are the main bioactive polyphenols in agrimony with well-documented antioxidant, anti-diabetic, and anti-inflammatory potential. We report here for the first time that agrimonolide and desmethylagrimonolide stimulate the expression of phase II detoxifying enzymes through the Nrf2-dependent signaling pathway. Agrimonolide and desmethylagrimonolide also possess considerable protective activity from oxidative DNA damage. In order to explore the cytoprotective potential of agrimonolide and desmethylagrimonolide on oxidative stress in liver, we developed an oxidative stress model in HepG2 cells, and check the hypothesis whether Nrf2 pathway is involved. Western blotting and luciferase assay revealed that exposure of HepG2 cells to agrimonolide or desmethylagrimonolide leads to increased heme oxygenase-1 (HO-1) expression by activating ARE through induction of Nrf2 and suppression of Kelch-like ECH-associated protein 1 (Keap1). Moreover, agrimonolide and desmethylagrimonolide also activated ERK signaling pathways and significantly attenuated individual p38 MAPK expression, subsequently leading to Nrf2 nuclear translocation. In conclusion, our results indicated that transcriptional activation of Nrf2/ARE is critical in agrimonolide and desmethylagrimonolide-mediated HO-1 induction, which can be regulated partially by the blockade of p38 MAPK signaling pathway and inhibiting nuclear translocation of Nrf2.

CHIR99021 combined with retinoic acid promotes the differentiation of primordial germ cells from human embryonic stem cells.

Primordial germ cells (PGCs) derived from human embryonic stem cells (hESCs) represent as a desirable experimental model as well as a potential strategy for treating male infertility. Here, we developed a simple and feasible method for differentiation of PGCs from hESCs by using CHIR99021 (an inhibitor of glycogen synthase kinase 3) and retinoic acid (RA). We firstly found that the deleted in azoospermia-like (DAZL) protein can be detected in 3 d CHIR99021 plus 9 d retinoic acid treated cultures and 12 d CHIR99021 plus retinoic acid co-treated cultures, but not expressed in single CHIR99021 treated cultures, single retinoic acid treated cultures, as well as 3 d retinoic acid plus 9 d CHIR99021 treated cultures. Next, we showed that several PGCs’ markers were expressed in the 12 d CHIR99021 and retinoic acid co-treated cultures or 3 d CHIR99021 plus 9 d retinoic acid treated cultures. Moreover, meiosis was initiated in CHIR99021 and retinoic acid co-treated cultures as evidenced by a significant expression of the punctate synaptonemal complex protein 3 (SCP3). Fluorescent in situ hybridization (FISH) analysis indicated that a small percentage of putative 1N populations were formed. Mechanically, we found that β-catenin relocated into nucleus after the treatment of 3 d CHIR99021 suggesting that Wnt signaling pathway was activated. Furthermore, blockade of Wnt signaling pathway by IWR-1 can reverse CHIR99021 and retinoic acid mediated-effects. Taken together, our results indicate that CHIR99021 combined with retinoic acid can effectively differentiate hESCs into PGCs via activating Wnt signaling pathway.

Targeting MAPK Signaling Pathway with Cobimetinib (GDC-0973) Enhances Anti-Leukemia Efficacy of Venetoclax (ABT-199/GDC-0199) in Acute Myeloid Leukemia Models

Despite advances in understanding of the biology of acute myeloid leukemia (AML), cure remains elusive for the majority of patients. Pro-survival molecules of BCL-2 family play critical roles in leukemia transformation and chemoresistance. The anti-leukemia potency of selective BCL-2 inhibitor venetoclax (ABT-199/GDC-0199) has been demonstrated in AML models (Pan et al. Cancer Discovery 2014). However, venetoclax is often associated with resistance due to its poor inhibition of MCL-1. RAF/MEK/ERK (MAPK) pathway is commonly activated in AML, and can stabilize anti-apoptotic MCL-1 and inactivate the pro-apoptotic BIM. In this study, we evaluated the anti-leukemia effects of concomitant BCL-2 and MAPK blockade by venetoclax in combination with MEK1/2 inhibitor GDC-0973 (cobimetinib).First, anti-leukemia activity of cobimetinib and venetoclax was examined in 18 primary AML samples with diverse genetic alterations. The combination significantly enhanced cell death, as compared to the single agent treatment (Fig 1A). Cobimetinib inhibited cell proliferation in the majority of AML cases (34.2 ± 23.7%) and the cell growth suppression was more profound in the combination group (60.2 ± 28.8%, p<0.001) (Fig 1A). The clonogenic potential of myeloid progenitors was significantly suppressed by the combination (82.5 ± 20.0%), as compared to cobimetinib (38.3 ± 14.6%, p=0.01) or venetoclax (41.9 ± 18.6%, p<0.05). The normal progenitor function was minimally affected.We next investigated signaling patterns and BCL-2 family protein expression in AML stem/progenitor cells using a 34-antibody panel for CyTOF. In AML 4400240, we identified 10 distinct subpopulations based on cell surface marker expression that were used to build the SPADE tree. BCL-2 and MCL-1 were both enriched in progenitor populations phenotypically positive for CD34, CD38, CD123 and HLA-DR (A2-5 and A9-10, Fig 1B and 1C). G-CSF-induced p-ERK and SCF-induced p-S6 signaling pathways were efficiently suppressed by cobimetinib (Fig 1D). The inhibition of p-S6 may reflect the sensitivity to cobimetinib of this sample (IC50=1.68 nM); consistent with previous study that suppression of TORC1 predicted response to MEK inhibitor (Corcoran et al. Sci Transl Med 2013).We have previously reported activity of venetoclax/cobimetinib combination in a panel of myeloid leukemia cell lines and revealed distinct response patterns to single agents and combination (Han et al. ASH 2015). Functional proteomics RPPA data indicated that p-ERK, p-S6 and p-RSK pathways were significantly down-regulated in response to the combination in cells showing synergy. Western blotting was performed to validate the RPPA data in 4 cell lines representing different response patterns. Cobimetinib inhibited p-ERK when used at high dose (1 _M) in all cell lines. In turn, inhibition of p-S6 at both ser235/236 and ser240/244 sites occurred at low dose of cobimetinib in sensitive cell lines (OCI-AML3 and MV4-11) and required high dose in resistant lines. In OCI-AML3 cells that showed synergy to combination, elevated levels of cleaved PARP was observed in the combination group, which was likely due to suppression of both BCL2:BIM and MCL-1:BIM complex, followed by release of free BIM to induce cell death.To test the efficacy in vivo, we injected NSGS mice with genetically engineered MOLM3/Luc/GFP cells. Bioluminescent imaging demonstrated significantly reduced leukemia burden in treated groups compared to controls, more prominently in the venetoclax (100 mg/kg/d) group and in venetoclax plus cobimetinib (10 mg/kg/d) co-treated mice (Fig 1E and 1F). Human CD45 engraftment and cell counts in both bone marrow and spleen demonstrated a trend towards decreased tumor burden when venetoclax was combined with cobimetinib in vivo (Fig 1G and 1H).In summary, combinatorial blockade of MAPK and BCL-2 pathways promotes cell death and suppresses proliferation in the majority of primary AML cells. The anti-leukemia efficacy of combined blockade of signaling and pro-survival pathways is associated with downregulation of MCL-1, release of pro-death BIM and suppression of p-S6. Additional novel transcriptional biomarkers of response are now being analyzed and will be presented. Combined efficacy of these agents is under clinical investigation in a Phase I trial in elderly relapsed/refractory AML (NCT02670044). [Display omitted] DisclosuresLeverson:AbbVie: Employment, Other: Shareholder in AbbVie. Monique:Genentech: Employment. Phillips:AbbVie Inc.: Employment. Chen:AbbVie: Employment. Jin:AbbVie Inc.: Employment. Daver:Ariad: Research Funding; Sunesis: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Kiromic: Research Funding; BMS: Research Funding; Otsuka: Consultancy, Honoraria; Karyopharm: Honoraria, Research Funding. Jabbour:ARIAD: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Research Funding; BMS: Consultancy. Kantarjian:Bristol-Myers Squibb: Research Funding; ARIAD: Research Funding; Amgen: Research Funding; Pfizer Inc: Research Funding; Delta-Fly Pharma: Research Funding; Novartis: Research Funding. Sampath:Genentech: Employment. Konopleva:AbbVie: Research Funding; Genentech: Research Funding.

Inhibition of Notch Signaling Attenuates Schistosomiasis Hepatic Fibrosis via Blocking Macrophage M2 Polarization.

Macrophages play a key role in the pathogenesis of liver granuloma and fibrosis in schistosomiasis. However, the underlying mechanisms have not been fully characterized. This study revealed that the macrophages infiltrating the liver tissues in a murine model of Schistosoma japonica infection exhibited M2 functional polarization, and Notch1/Jagged1 signaling was significantly upregulated in the M2 polarized macrophages in vivo and in vitro. Furthermore, the blockade of Notch signaling pathway by a γ–secretase inhibitor could reverse macrophage M2 polarization in vitro and alleviate liver granuloma and fibrosis in the murine model of schistosomiasis. These results implied that the Notch1/Jagged1 signaling-dependent M2 polarization of macrophages might play an important role in liver granuloma and fibrosis in schistosomiasis, and the inhibition of Notch1/Jagged1 signaling might provide a novel therapeutic approach to administrate patients with schistosomiasis.

257 - Agrimonolide and Desmethylagrimonolide from Agrimonia Pilosa Ledeb Induced HO-1 Expression in HepG2 Cells through Nrf2-Transduction and P38 Inactivation

The antioxidant activities and superoxide dismutase (SOD)-like effects of agrimonolide and desmethylagrimonolid from Agrimonia pilosa Ledeb were investigated. The exposure of HepG2 cells to agrimonolide or desmethylagrimonolide will improve the expression of heme oxygenase-1 (HO-1). Agrimonolide and desmethylagrimonolid effectively attenuated H 2 O 2 -induced cell damage. The mechanisms underlying this protective effect include: (1) free radicals scavenging activities, (2) activation of Nrf2-driven pathways; (3) inhibition of p38 phosphorylation (4) activation of ERK, JNK, and MAPK phosphorylation; (5) elevation of the activity of antioxidative enzymes SOD; (6) increased expression of HO-1. In conclusion, our results indicated that transcriptional activation of Nrf2/ARE is critical in agrimonolide and desmethylagrimonolide-mediated HO-1 induction, which can be regulated in part by the blockade of p38 MAPK signaling pathway and inhibiting nuclear translocation of Nrf2.

Design and discovery of 4-anilinoquinazoline-urea derivatives as dual TK inhibitors of EGFR and VEGFR-2

EGFR and VEGFR-2 are involved in pathological disorders and the progression of different kinds of tumors, the combined blockade of EGFR and VEGFR signaling pathways appears to be an attractive approach to cancer therapy. In this work, a series of 4-anilinoquinazoline derivatives containing substituted diaryl urea or glycine methyl ester moiety were designed and identified as EGFR and VEGFR-2 dual inhibitors. Compounds 19i, 19j and 19l exhibited the most potent inhibitory activities against EGFR (IC50 = 1 nM, 78 nM and 51 nM, respectively) and VEGFR-2 (IC50 = 79 nM, 14 nM and 14 nM, respectively), they showed good antiproliferative activities as well. Molecular docking established the interaction of 19i with the DFG-out conformation of VEGFR-2, suggesting that they might be type II kinase inhibitors.

Interleukin-7 Modulates Anti-Tumor CD8+ T Cell Responses via Its Action on Host Cells.

The adoptive transfer of antigen-specific CD8+ T cells is a promising approach for the treatment of chronic viral and malignant diseases. In order to improve adoptive T cell therapy (ATT) of cancer, recent strategies aim at the antibody-based blockade of immunosuppressive signaling pathways in CD8+ T cells. Alternatively, adjuvant effects of immunostimulatory cytokines might be exploited to improve therapeutic CD8+ T cell responses. For example, Interleukin-7 (IL-7) is a potent growth, activation and survival factor for CD8+ T cells that can be used to improve virus- and tumor-specific CD8+ T cell responses. Although direct IL-7 effects on CD8+ T cells were studied extensively in numerous models, the contribution of IL-7 receptor-competent (IL-7R+) host cells remained unclear. In the current study we provide evidence that CD8+ T cell-mediated tumor rejection in response to recombinant IL-7 (rIL-7) therapy is strictly dependent on IL-7R+ host cells. On the contrary, CD8+ T cell expansion is independent of host IL-7R expression. If, however, rIL-7 therapy and peptide vaccination are combined, host IL-7R signaling is crucial for CD8+ T cell expansion. Unexpectedly, maximum CD8+ T cell expansion relies mainly on IL-7R signaling in non-hematopoietic host cells, similar to the massive accumulation of dendritic cells and granulocytes. In summary, we provide evidence that IL-7R+ host cells are major targets of rIL-7 that modulate therapeutic CD8+ T cell responses and the outcome of rIL-7-assisted ATT. This knowledge may have important implications for the design and optimization of clinical ATT protocols.

Schedule-dependent interaction between temsirolimus and cetuximab in head and neck cancer: a preclinical study.

Aberrant epidermal growth factor receptor (EGFR) signaling is associated with tumor growth in head and neck squamous cell carcinoma (HNSCC) and is a major focus of targeted therapy. The phosphatidylinositol-3-kinase/AKT/mammalian target of the rapamycin (PI3K/AKT/mTOR) signaling pathway is frequently mutated in HNSCC and is involved in disease progression and resistance to EGFR inhibitors. The aim of this study was to assess the antiproliferative effects of mTOR inhibition (temsirolimus) combined with the anti-EGFR monoclonal antibody cetuximab, administered according to different combination schedules. Antiproliferative effects of the combination of temsirolimus and cetuximab were determined on the representative HNSCC CAL33 cell line (PI3KCA H1047R mutated and K-RAS wild-type). In addition, key proteins related to the EGFR pathway (pEGFR/EGFR, pAKT/AKT) and the mTOR pathway (p-p70S6K1, p4E-BP1) were determined to explain the cytotoxic effects. Temsirolimus and cetuximab showed a synergistic effect when administered in combination. Supra-additive effect was lost when the two drugs were administered sequentially, irrespective of which drug was administered first. Synergistic effect of the combination was corroborated by a marked downregulation of pEGFR, significant downregulation of pAKT expression, and a marked diminution of p70S6K1 and p4E-BP1 expression. Our study demonstrated a synergistic effect of temsirolimus and cetuximab administered in combination, well illustrated by a simultaneous blockade of intracellular signaling pathways regulating cell proliferation and survival. These results establish the notion of a schedule dependency for the combined treatment, which can be of importance at the clinical level.

Systematic analysis of factors influencing observations of biased agonism at the mu-opioid receptor

Biased agonism describes the ability of distinct G protein-coupled receptor (GPCR) ligands to stabilise distinct receptor conformations leading to the activation of different cell signalling pathways that can deliver different physiologic outcomes. This phenomenon is having a major impact on modern drug discovery as it offers the potential to design ligands that selectively activate or inhibit the signalling pathways linked to therapeutic effects with minimal activation or blockade of signalling pathways that are linked to the development of adverse on-target effects. However, the explosion in studies of biased agonism at multiple GPCR families in recombinant cell lines has revealed a high degree of variability on descriptions of biased ligands at the same GPCR and raised the question of whether biased agonism is a fixed attribute of a ligand in all cell types. The current study addresses this question at the mu-opioid receptor (MOP). Here, we have systematically assessed the impact of differential cellular protein complement (and cellular background), signalling kinetics and receptor species on our previous descriptions of biased agonism at MOP by several opioid peptides and synthetic opioids. Our results show that all these factors need to be carefully determined and reported when considering biased agonism. Nevertheless, our studies also show that, despite changes in overall signalling profiles, ligands that previously showed distinct bias profiles at MOP retained their uniqueness across different cell backgrounds.

A therapeutic trial of human melanomas with combined small interfering RNAs targeting adaptor molecules p130Cas and paxillin activated under expression of ganglioside GD3

We previously demonstrated that focal adhesion kinase (FAK), p130Cas and paxillin are crucially involved in the enhanced malignant properties under expression of ganglioside GD3 in melanoma cells. Therefore, molecules existing in the GD3-mediated signaling pathway could be considered as suitable targets for therapeutic intervention in malignant melanoma. The aim of this study was to determine whether blockade of p130Cas and/or paxillin by RNAi suppresses melanoma growth. We found a suitable dose (40μM siRNA, 25μl/tumor) of the siRNA to suppress p130Cas in the xenografts generated in nu/nu mice. Based on these results, we performed intratumoral (i.t.) treatment with anti-p130Cas and/or anti-paxillin siRNAs mixed with atelocollagen as a drug delivery system in a xenograft tumor of a human melanoma cell line, SK-MEL-28. Mixture of atelocollagen (1.75%) and an siRNA (500 or 1000pmol/tumor) was injected into the tumors every 3days after the first injection. An siRNA against human p130Cas markedly suppressed tumor growth of the xenograft in a dose-dependent manner, whereas siRNA against human paxillin slightly inhibited the tumor growth. A control siRNA against firefly luciferase showed no effect. To our surprise, siRNA against human p130Cas (500 or 1000pmol/tumor) combined with siRNA against human paxillin dramatically suppressed tumor growth. In agreement with the tumor suppression effects of the anti-p130Cas siRNA, reduction in Ki-67 positive cell number as well as in p130Cas expression was demonstrated by immunohistostaining. These results suggested that blockade of GD3-mediated growth signaling pathways by siRNAs might be a novel and promising therapeutic strategy against malignant melanomas, provided signaling molecules such as p130Cas and paxillin are significantly expressed in individual cases. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.

Abstract P3-05-05: Targeting tumor re-wiring by triple blockade of mTORC1, ERBB and ER signaling pathways in endocrine resistant breast cancer

Abstract AIM To target tumor re-wiring by combined mTORC1 inhibition plus hormonal treatment with or without co-blockade of ERBB signaling in endocrine resistant models of human breast cancer (BC). BACKGROUND Around 80% of BCs are estrogen receptor positive (ER+). Endocrine therapies target estrogenic stimulation of tumor growth but resistance remains problematic. Several strategies have shown that resistance often depends on the acquisition of enhanced cross-talk between ER and growth-factor pathways, allowing the disease to circumvent the need for steroid hormones. We have previously reported the antiproliferative effects of the combination of everolimus (RAD001-mTORC1 inhibitor) with endocrine therapy in resistance models, but potential routes of escape from treatment via ERBB2/3 signaling were observed. We hypothesised that combined targeting of three signaling pathways, namely ER, ERBB and mTORC1 may provide enhanced anti-tumor activity. METHODS ER+ BC cell lines (MCF7, SUM44 and HCC1428) adapted to long term estrogen-deprivation (LTED) which model relapse on an aromatase inhibitor, along with their wild-type (wt) cell lines were treated with neratinib, a pan-ERBB tyrosine kinase inhibitor, in combination with RAD001 ± estradiol (E2), tamoxifen or fulvestrant. End points included proliferation, cell signaling, cell cycle and effect on ER-mediated transactivation and recruitment by ChIP. RESULTS All cell lines showed a concentration-dependent decrease in proliferation in response to RAD001 (IC50 0.6-50nM in absence of E2 and 1-10nM in presence of E2). A wide range of IC50 values (300-1000nM) was observed with neratinib treatment in the presence of E2. However, in the absence of E2, wt cell lines showed IC50 values in excess of 1800nM with hormetic dose response curves, in which lower concentrations induced cell proliferation. In contrast, LTED IC50 values ranged between 400-900nM. Combination of either agent with endocrine therapy caused a concentration dependent decrease in proliferation in all wt cell lines and their LTED derivatives, but the maximum effect was observed when a triple combination of RAD001, neratinib and ER-blockade was used. Expression of pS6 was dramatically suppressed by RAD001 ± neratinib in all cell lines tested, whilst neratinib caused a cell line specific reduction in expression of ERBB family proteins. Upregulation of pAKT was observed in all cell lines following treatment with RAD001, indicating both inhibitors were effectively suppressing their respective targets. Combination of RAD001 with neratinib suppressed the upregulation of pAKT and significantly reduced cell cycle progression. In the absence of E2, RAD001 caused a reduction in ER-mediated transcription and decrease in recruitment of ER and the CREB-binding protein (CBP) to the TFF1 promoter. In contrast, neratinib induced a marked increase in ER-recruitment and concomitant rise in ER-mediated transactivation, which was reduced by the addition of RAD001. CONCLUSION Targeting tumor re-wiring by triple blockade of ERBB, ER and mTORC1 signaling pathways significantly reduces cell proliferation supporting the potential combination in patients who have relapsed on endocrine therapy and retain a functional ER. Citation Format: Nikitorowicz-Buniak J, Ribas R, Rani A, Pancholi S, Guest SK, Cutler Jr RE, Lalani A, Dowsett M, Johnston SR, Martin L-A. Targeting tumor re-wiring by triple blockade of mTORC1, ERBB and ER signaling pathways in endocrine resistant breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-05-05.

NKCC1-Mediated GABAergic Signaling Promotes Postnatal Cell Death in Neocortical Cajal-Retzius Cells.

During early development, a substantial proportion of central neurons undergoes programmed cell death. This activity-dependent process is essential for the proper structural and functional development of the brain. To uncover cell type-specific differences in the regulation of neuronal survival versus apoptosis, we studied activity-regulated cell death in Cajal-Retzius neurons (CRNs) and the overall neuronal population in the developing mouse cerebral cortex. CRNs in the upper neocortical layer represent an early-born neuronal population, which is important for cortical development and largely disappears by apoptosis during neonatal stages. In contrast to the overall neuronal population, activity blockade with tetrodotoxin improved survival of CRNs in culture. Activation of GABAA receptors also blocked spontaneous activity and caused overall cell death including apoptosis of CRNs. Blockade of the Na-K-Cl transporter NKCC1 in vitro or its genetic deletion in vivo rescued CRNs from apoptosis. This effect was mediated by blockade of the p75NTR receptor signaling pathway. In summary, we discovered a novel developmental death pathway mediated by NKCC1, via GABAA receptor-mediated membrane depolarization and p75NTR signaling in CRNs. This pathway controls apoptosis of CRNs and may be critically involved in neurodevelopmental disorders such as autism and schizophrenia.

Mechanisms of vasodilation to PTH 1-84, PTH 1-34, and PTHrP 1-34 in rat bone resistance arteries.

Parathyroid hormone (PTH) augments bone metabolism and bone mass when given intermittently. Enhanced blood flow is requisite to support high tissue metabolism. The bone arteries are responsive to all three PTH analogs, which may serve to augment skeletal blood flow during intermittent PTH administration. PTH augments bone metabolism. Yet, mechanisms by which PTH regulates bone blood vessels are unknown. We deciphered (1) endothelium-dependent and endothelium-independent vasodilation to PTH 1-84, PTH 1-34, and PTHrP 1-34, (2) the signaling pathways (i.e., endothelial nitric oxide synthase [eNOS], cyclooxygenase [COX], protein kinase C [PKC], and protein kinase A [PKA]), and (3) receptor activation. Femoral principal nutrient arteries (PNAs) were given cumulative doses (10(-13)-10(-8)M) of PTH 1-84, PTH 1-34, and PTHrP 1-34 with and without signaling pathway blockade. Vasodilation was also determined following endothelial cell removal (i.e., denudation), PTH 1 receptor (PTH1R) inhibition and to sodium nitroprusside (SNP; a nitric oxide [NO] donor). Vasodilation was lowest to PTH 1-34, and maximal dilation was highest to PTHrP 1-34. Inhibition of eNOS reduced vasodilation to PTH 1-84 (-80%), PTH 1-34 (-66%), and PTHrP 1-34 (-48%), evidencing the contribution of NO. Vasodilation following denudation was eliminated (PTH 1-84 and PTHrP 1-34) and impaired (PTH 1-34, 17% of maximum), highlighting the importance of endothelial cells for PTH signaling. Denuded and intact PNAs responded similarly to SNP. Both PKA and PKC inhibition diminished vasodilation in all three analogs to varying degrees. PTH1R blockade reduced vasodilation to 1, 12, and 12% to PTH 1-84, PTH 1-34, and PTHrP 1-34, respectively. Vasodilation of femoral PNAs to the PTH analogs occurred via activation of the endothelial cell PTH1R for NO-mediated events. PTH 1-84 and PTHrP 1-34 primarily stimulated PKA signaling, and PTH 1-34 equally stimulated PKA and PKC signaling.

Effect of IL-17 monoclonal antibody Secukinumab combined with IL-35 blockade of Notch signaling pathway on the invasive capability of hepatoma cells.

We investigated the effect of the IL-17 monoclonal antibody Secukinumab combined with IL-35 in the blockade of the Notch signaling pathway on the invasive capability of hepatoma cells. We examined the effects of IL-17 antibody or IL-35 treatment alone or in combination on cell invasion and migration capabilities with Transwell chambers. The mRNA levels of Hes1, Hes5, and Hey1 were tested using quantitative polymerase chain reaction. The protein expression of N1ICD, Snail, and E-cadherin protein expressions were measured with western blot. The expression of Hes1, Hes5, Hey1 and N1ICD were all very high in hepatoma cell lines, and were positively correlated with the invasive migration capabilities of the cells. The combination of IL-17 monoclonal antibody Secukinumab with IL-35 could effectively inhibit the Notch signaling pathway, as well as the invasive migration of the cells. Snail and E-cadherin are involved in the migration of hepatoma cells, and it has been established that Snail can regulate the expression of E-cadherin. IL-17 monoclonal antibody Secukinumab combined with IL-35 can increase E-cadherin and decrease Snail expression, which are positively correlated with cell invasive migration capabilities. Overall, treatment with both IL-17 antibody and IL-35 is more effective than each treatment alone. Notch signaling is activated in hepatoma cell lines and increases with the enhancement of cell invasive migration capabilities. IL-17 monoclonal antibody Secukinumab combined with IL-35 can block the Notch signaling pathway, simultaneously reducing the invasive migration capability of hepatoma cells.

Releasing the Brakes in Cancer

Cancer is a heterogeneous group of diseases where abnormal cell growth with potential to invade other body parts takes control of normal homeostasis and becomes fatal if not timely and rightly treated. There are more than 100 types of cancers characterized so far and many yet to be identified. World Health Organization estimates, that worldwide in 2012 there were 4 million new cancer cases and 8.2 million cancer related deaths. Amongst various treatment options available for cancer, immunotherapy offers an approach where the focus is on enhancing or even inducing an antitumor immune response. Induction or enhancement of anti-tumor immune response is a formidable challenge in cancer because tumor cells use multiple immune evasion strategies and avoid being detected or eliminated by immune cells. Immune checkpoints refer to a network of stimulatory or inhibitory signaling pathways in the immune system which are critical in maintaining self-tolerance, limiting tissue damage and modulating the quality of immune response. Substantial evidence indicates that up regulation of inhibitory signaling molecules (CTLA - 4, PD - 1) by tumor cells subvert activation of tumor antigen specific Teffector cells. Therefore, blockade of inhibitory signaling pathways may be one potential way of revitalizing an exhausted immune response in tumors. Using this approach, antibodies directed against CTLA - 4 and PD - 1 have been shown an acceptable therapeutic benefit in preclinical models and cancer patients. This review will discuss the important immune checkpoints that have been identified critical to suppress anti-tumor immunity and have been exploited as drug targets.

Significant blockade of multiple receptor tyrosine kinases by MGCD516 (Sitravatinib), a novel small molecule inhibitor, shows potent anti-tumor activity in preclinical models of sarcoma

Sarcomas are rare but highly aggressive mesenchymal tumors with a median survival of 10–18 months for metastatic disease. Mutation and/or overexpression of many receptor tyrosine kinases (RTKs) including c-Met, PDGFR, c-Kit and IGF1-R drive defective signaling pathways in sarcomas. MGCD516 (Sitravatinib) is a novel small molecule inhibitor targeting multiple RTKs involved in driving sarcoma cell growth. In the present study, we evaluated the efficacy of MGCD516 both in vitro and in mouse xenograft models in vivo. MGCD516 treatment resulted in significant blockade of phosphorylation of potential driver RTKs and induced potent anti-proliferative effects in vitro. Furthermore, MGCD516 treatment of tumor xenografts in vivo resulted in significant suppression of tumor growth. Efficacy of MGCD516 was superior to imatinib and crizotinib, two other well-studied multi-kinase inhibitors with overlapping target specificities, both in vitro and in vivo. This is the first report describing MGCD516 as a potent multi-kinase inhibitor in different models of sarcoma, superior to imatinib and crizotinib. Results from this study showing blockade of multiple driver signaling pathways provides a rationale for further clinical development of MGCD516 for the treatment of patients with soft-tissue sarcoma.

A potent therapeutics for gallbladder cancer by combinatorial inhibition of the MAPK and mTOR signaling networks.

Gallbladder cancer (GBC) is the most common type of cancer with the worst prognosis among the bile duct cancers. There still remains a clear need for effective mechanism-based novel therapeutic approaches. A crosstalk between mitogen-activated protein kinase (MAPK) and the mammalian target of Rapamycin (mTOR) signaling pathways has been reported in several cancers. We hypothesized that targeting both pathways in combination will be a potent therapeutic for GBC. Expression of phospho-ERK and phospho-S6rp protein were evaluated by immunostaining in surgically resected GBC specimens (n=30). GBC cell lines and a xenograft model were treated with CI-1040, an inhibitor of MEK (mitogen-activated protein kinase kinase) and RAD001, an inhibitor of mTOR, alone or in combination, and then, we examined the cell proliferation and tumor growth, cell cycle status, and apoptosis. Analysis of human GBC tissues demonstrated that MAPK and mTOR signaling pathways were frequently coordinately dysregulated in one third of them. The combination therapy inhibited both signaling pathways and subsequently inhibited human GBC cell proliferation in vitro and xenograft tumor growth in vivo. Compared to the single treatment, the combination therapy significantly induced cell cycle arrest and apoptosis with decreased cyclin D1 expression. The double blockade of MAPK and mTOR signaling pathways inhibits the signal crosstalk and shows anti-tumor activity, which can be a potent therapeutic for GBC, especially for the patients with hyperactivated signaling of both pathways.

Role of PI3K, ERK, and p38 Signaling Pathways in the Production of Humoral Erythropoiesis Regulators under Normal Conditions

PI3- and MAP-kinase signaling pathways duplicate and interchange each other in production of agents that determine total erythropoietic activity under conditions of balanced erythropoiesis. The alternative p38-dependent MAP-kinase pathway is the major regulator of erythropoietic activity of adherent bone marrow cells. Blockade of PI3K and p38 signaling pathways stimulated production of erythropoietin by cells that do not produce it constitutively.

Transforming growth factor-β signaling pathway cross-talking with ERα signaling pathway on regulating the growth of uterine leiomyoma activated by phenolic environmental estrogens in vitro.

The aim of this paper is to study the participation of transforming growth factor-β (TGF-β) signaling pathway in mediating the growth of human uterine leiomyoma (UL) activated by phenolic environmental estrogens (EEs), via the interaction between TGF-β and ER signaling pathways. The UL cells were prepared by primary culture and subculture methods. To validate the role of TGF-β3 (5ng/ml) for the viability of human uterine leiomyoma cells, CCK-8 assay was performed in each of five treatment groups including E2 group (E2 10(9)mol/l), BPA group (bisphenol A 10μmol/l), NP group (nonylphenol 32μmol/l), OP group (octylphenol 8μmol/l), or control group (DMSO only). Subsequently, qRT-PCR was applied to detect mRNA expressions of ERα and c-fos, while western blot assay was used to test the expressions of p-Smad3, SnoN, and c-fos proteins in all settings mentioned above; the expressions were compared among different groups, and also in settings with and without synchronous treatment of ICI 182,780. Primarily cultured UL cells were successfully established. Compared with the control group, there were statistically significant increases in the proliferation rate of the UL cells in all EE groups or treated with TGF-β3 only (p < 0.05). Nevertheless, a slight decrease in proliferation rate of UL was detected in coexistence with TGF-β3 in all EE groups (p > 0.05). Interestingly, mRNA expressions of ERα and c-fos reduced in the setting of coexistence of TGF-β3 and EEs compared to isolated EE treatment (p < 0.05). Compared with the control group, the expression of p-Smad3 and c-fos proteins significantly decreased (p < 0.05) in each of E2, BPA, NP, and OP group, and the expression of SnoN protein also significantly reduced only in BPA and NP groups (p < 0.05), followed by TGF-β3 treatment. When adding ICI 182,780, the expression of p-Smad3 protein significantly increased in OP group (p < 0.05), but slightly increased in E2, BPA, NP, and OP groups (p > 0.05). However, compared with the control group, the expressions of SnoN and c-fos proteins significantly decreased (p < 0.05) after adding ICI182,780. Moreover, there was a significant statistical difference in the expression of p-Smad3, SnoN, and c-fos proteins between pre- and post-treatment of ICI 182,780 in all groups (p < 0.05). The ERα signaling pathway and TGF-β signaling pathway have different roles in the control of UL cell proliferation. The phenolic EEs can be a promoter of UL cell proliferation, which is mediated by ERα signaling pathway and its cross-talking with TGF-β signaling pathway. Both less exposure to EEs and blockade of TGF signaling pathway are necessary strategies to prevent UL.

Pertuzumab: Unprecedented benefit in human epidermal growth factor receptor 2-positive breast cancer

ABSTRACTHuman epidermal growth factor receptor 2 (HER2)-positive breast cancer is a more aggressive subtype of breast cancer and targeting the HER2 receptor has proven effective in improving the prognosis of these patients. Pertuzumab, a recombinant humanized monoclonal antibody and the first in a class of HER2 dimerization inhibitors approved for treating HER2+ breast cancer. It blocks ligand-dependent heterodimerization and ligand-independent homodimerization of HER2 with other HER members. When used in combination with trastuzumab and taxane, pertuzumab complements the action of trastuzumab and results in a comprehensive blockade of HER2 signaling pathway. This review article traces the development of pertuzumab from concept to its current use in HER2+ breast cancer treatment. A search of Medical Literature Published since 2007 was performed in PubMed using the keywords “pertuzumab,” “HER2+ breast cancer,” “HER2 targeted therapy,” “metastatic breast cancer,” and in search engines for ongoing trials with pertuzumab and incidence of cancer and breast cancer in India. A total of 35 publications and abstracts from the American Society of Clinical Oncology were selected for this review. Pertuzumab is approved in combination with trastuzumab and docetaxel for the treatment of patients with HER2+ metastatic BC, who have not received prior anti-HER2 therapy or chemotherapy for metastatic disease. The dual HER2 blockade of pertuzumab and trastuzumab is now accepted worldwide as a standard of care by various guidelines.