bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2308: Sigma-2 receptor ligands induce apoptosis and inhibit proliferation in breast cancer cell line mda-mb-231
Authors: Asong Gladys , Amissah Felix , Salako Olufisayo , Poku Rosemary , Ntantie Elizabeth , Nkembo Augustine , Lamango Nazarius , Ablordeppey Seth 
Published: July 2017

Abstract
Introduction: Despite the reduction in mortality from breast cancer achieved in the last 30 years due to more effective targeted therapies, the survival rate for patients with triple negative breast cancer (TNBC) is poor and has virtually plateaued. Due to the absence of estrogen, progesterone, and human epidermal growth factor receptors 2, no targeted treatment options are currently available for TNBC. Moreover, the current standard systemic treatments are known to cause tremendous side effects. Thus, there is an urgent need to identify novel strategies for treating TNBC. Several reports have revealed that sigma-2 receptors are over-expressed in all solid tumors including TNBC, making it a plausible biomarker to explore for TNBC treatment. In this study, we investigated the effects of novel sigma-2 receptor ligands (XYZ-XI-14 and XYZ-VII-69) synthesized in our lab on the viability and survival of the TNBC, MDA-MB-231.
Methods: MDA-MB-231 cells were treated for 48 h with XYZ-XI-14 and XYZ-VII-69, cell viability and proliferation were assessed using resazurin cell titre assay and cell count methods respectively. The effects of the ligands on spheroids formation, cell cycle, and mode of cell death were also investigated.
Results: XYZ-XI-14 and XYZ-VII-69 decreased cell viability of MDA-MB-231 cells in a concentration-dependent manner. The EC50 for XYZ-XI-14 and XYZ-VII-69 were 12 and 13 µM respectively; and at 5 µM, the ligands inhibited cell proliferation, induced apoptosis, and arrested MDA-MB-231 cells at the G0/G1 phase of cell cycle. Additionally, concentrations of the ligand as low as 1 µM prevented the formation of spheroids as evidenced by the lack of compact spheroids, and caused the disintegration of preformed spheroids.
Conclusion: This study indicates that targeting sigma-2 receptors with novel sigma-2 ligands (XYZ-XII-14 and XYZ-VII-69) effectively inhibits TNBC cancer cell growth by inducing apoptosis and cell cycle arrest, thus presenting a unique and effective pathway for treating TNBC. Additionally, the sigma-2 receptor ligands (XYZ-XI-14 and XYZ-VII-69) have the potential to halt tumor growth and prevent tumor relapse, as seen in our 3D culture assays. Thus, the sigma-2 receptor has the potential to be a valuable target for the development of novel agents for the treatment of TNBC.
Citation Format: Gladys Asong, Felix Amissah, Olufisayo Salako, Rosemary Poku, Elizabeth Ntantie, Augustine Nkembo, Nazarius Lamango, Seth Ablordeppey. Sigma-2 receptor ligands induce apoptosis and inhibit proliferation in breast cancer cell line mda-mb-231 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2308. doi:10.1158/1538-7445.AM2017-2308
Abstract 2310: Molecular dynamics simulation of permeation pathway of cytochrome C through Bax pore
Authors: Zhang Mingzhen , Zheng Jie , Nussinov Ruth , Ma Buyong 
Published: July 2017

Abstract
How cytochrome C is released from the mitochondria to the cytosol via Bax oligomeric pores, a process which is required for apoptosis, is still a mystery. Based on the residue-residue distances detected experimentally for Bax and its homologous protein (Bak), we recently computationally solve the first atomic model for Bax oligomeric pores at the membranes. Next, we investigate the mechanism at the microsecond time- and nanometer space- scale using coarse-grained replica exchange and all-atom MD simulations. Our free energy landscape depicts a low barrier for the permeation of cytochrome C into the Bax C-terminal mouth, with the pathway proceeding to the inner cavity and exiting via the N-terminal mouth. Release is guided by organized charged/hydrophilic surfaces. The hydrophilicity and negative charge of the pore surface gradually increase along the release pathway from the pore entry to the exit opening. Rather than inert passing of cytochrome C through a rigid pore, the flexible pore may selectively aid the cytochrome C passage. The energy barrier is under 4 kcal/mol. Thus, once the Bax pore is formed in the membrane, the release of cytochrome C may be readily achieved through energy fluctuations. Collectively, our work provides mechanistic insight and atomic detail into the release of cytochrome C through Bax oligomeric pores.
Citation Format: Mingzhen Zhang, Jie Zheng, Ruth Nussinov, Buyong Ma. Molecular dynamics simulation of permeation pathway of cytochrome C through Bax pore [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2310. doi:10.1158/1538-7445.AM2017-2310
Abstract 2329: TMEM33 induces apoptosis via UPR signaling and autophagy in breast cancer cells
Authors: Hu Rong , Zhang Xiyuan , Hilakivi-Clarke Leena , Kasid Usha , Clarke Robert 
Published: July 2017

Abstract
TMEM33 is a novel transmembrane protein that resides in the endoplasmic reticulum (EnR). It has been shown to activate the PERK and IRE1α branches of the unfolded protein response (UPR). However, the underlying mechanism of action of this EnR resident protein TMEM33 and the cellular functions that it regulates remain largely unknown. In this study, we show that overexpression of TMEM33 induces robust cell death in breast cancer cells. Inhibition of the PERK/eIF2alpha pathway with eIF2alpha inhibitor ISRIB blocks the TMEM33 induced cell death. TMEM33 overexpression strongly activates UPR associated pro-death JNK-p53 signaling. We also observed a significant inhibition of the downstream survivin, which blocks cell death activation by binding to caspases and inhibiting their activation. We further show that the blockage of JNK activation with either an inhibitor or overexpression of survivin, protects cells against TMEM33 induced apoptosis. In addition, we show that TMEM33 overexpression induces autophagy in breast cancer cells. Inhibition of autophagy with using either the inhibitor chloroquine or knockdown of the Atg5 gene, further sensitizes breast cancer cells to the effects of TMEM33 overexpression. Cell death induced by TMEM33 is also decreased by overexpression of the autophagy gene Beclin 1. The findings in this study demonstrate that the novel EnR resident protein TMEM33 induces cell death by activating IRE1α-JNK-p53-survivin signaling in breast cancer cells. Concurrently, autophagy is also activated by TMEM33, and functions as a pro-survival mechanism. Cell fate reflects the balance between the pro-death and pro-survival activities as regulated by TMEM33.
Citation Format: Rong Hu, Xiyuan Zhang, Leena Hilakivi-Clarke, Usha Kasid, Robert Clarke. TMEM33 induces apoptosis via UPR signaling and autophagy in breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2329. doi:10.1158/1538-7445.AM2017-2329
Abstract 2332: Integral modulation of nuclear factor-kappa B activation by C/EBPβ and the endoplasmic reticulum stress sensor PERK to mediate estrogen-induced apoptosis in estrogen-deprived breast cancer cells
Authors: Fan Ping , Tyagi Amit K. , Agboke Fadeke A. , Pokharel Niranjana , Jordan V. Craig 
Published: July 2017

Abstract
Stress responses are critical for estrogen (E2) to induce apoptosis in E2-deprived breast cancer cells. Nuclear factor-kappa B (NF-κB) is well known as a therapeutic target to prevent stress responses in chronic inflammatory diseases including cancer. However, whether E2 activates NF-κB to participate in stress-associated apoptosis in E2-deprived breast cancer cells is unclear. We demonstrated that E2 differentially modulates NF-κB activity in E2-deprived breast cancer cells according to the treatment time. Because E2 initially has significant potential to down modulate the NF-κB activation, it completely suppresses the tumor necrosis factor alpha (TNFα)-induced NF-κB activation. We found that E2 preferentially and constantly enhances the expression of transcription factor CCAAT/enhancer binding protein beta (C/EBPβ) which is responsible for suppression of NF-κB activation by E2 in MCF-7:5C cells. The mTOR signaling pathway promotes repression of NF-κB by C/EBPβ which is confirmed by the evidence that inhibition of mTOR is synergistic with E2 to upregulate NF-κB-dependent genes, such as TNFα. Interestingly, NF-κB p65 activity is upregulated when E2-treatment is administered for 48 hours, leading to induction of TNFα. Blocking the nuclear translocation of NF-κB completely prevents E2 from induction of TNFα and apoptosis. Importantly, protein kinase RNA-like endoplasmic reticulum kinase (PERK), a stress sensor of unfolded protein response, is activated by E2 and plays an essential role in increasing NF-κB p65 DNA binding through the activation of STAT3, independently of canonical IκBα signal pathway. Thus, inhibition of PERK kinase activity completely blocks nuclear activation of NF-κB and NF-κB-dependent induction of TNFα, thereby preventing E2-induced apoptosis. All of these findings illustrate a crucial role for the novel PERK/NF-κB/TNFα axis in E2-induced apoptosis which is integrally modulated by the stress responsive transcription factor C/EBPβ and endoplasmic reticulum stress. This study provides an important rationale for exercising caution in clinical trials when considering targeting PERK or NF-κB following the development of acquired resistance to aromatase inhibitors whereas mTOR may be a target to enhance the therapeutic effects of E2 in antihormone resistant breast cancer.
Citation Format: Ping Fan, Amit K. Tyagi, Fadeke A. Agboke, Niranjana Pokharel, V. Craig Jordan. Integral modulation of nuclear factor-kappa B activation by C/EBPβ and the endoplasmic reticulum stress sensor PERK to mediate estrogen-induced apoptosis in estrogen-deprived breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2332. doi:10.1158/1538-7445.AM2017-2332
Abstract 2342: TNFAIP8 promotes prostate cancer cell survival by modulating autophagy
Authors: Niture Suresh , Ramalinga Malathi , Kedir Habib , Kumar Deepak 
Published: July 2017

Abstract
TNF-α inducible protein (TNFAIP8) is an antiapoptotic protein with roles in tumor cell growth and survival. Mechanisms of cell survival by TNFAIP8 remains elusive. In the current study, we investigated the role and molecular mechanism related to TNFAIP8 in the modulation of cell/cycle, autophagy and drug resistance/cell survival in prostate cancer cells. Microarray data from PC3 prostate cancer cells ectopically expressing TNFAIP8 demonstrated modulation of cell cycle related genes such as CDKs, CDCs and PCNA. Immunoblotting data from overexpression of TNFAIP8 in PC3 cells shows upregulation of cell cycle proteins cyclin A, cyclin B1, Myt1 and Chk1. However, no change in cell cycle was found. Phosphorylation of Histone-S10, CDC2-Tyr15 and Wee1-S642] was also observed. Autophagy plays an important role in tumor cell survival. We evaluated the effects of TNFAIP8 in modulating autophagy. Overexpression of TNFAIP8 leads to induction of autophagy. TNFAIP8 positively modulates the expression/stabilization of autophagy markers and effectors such as LC3β I/II, Beclin1, 4EBP1, oncogene p62 and SIRT1. Knockdown of TNFAIP8 inhibits autophagy induced by nutrient starvation in PC3 prostate and MCF7 breast cancer cells. We also evaluated cell growth and survival in PC3 cells. We demonstrate that TNFAIP8 promotes cell growth and proliferation in PC3, LNCaP and C4-2 prostate cancer cells. Furthermore, we have found that TNFAIP8 increase resistance against anticancer drugs docetaxel and doxorubicin. These data collectively suggest that by the creation of cellular autophagy events TNFAIP8 promotes cell survival and drug resistance in prostate cancer cells.
Citation Format: Suresh Niture, Malathi Ramalinga, Habib Kedir, Deepak Kumar. TNFAIP8 promotes prostate cancer cell survival by modulating autophagy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2342. doi:10.1158/1538-7445.AM2017-2342
Abstract 2345: CDK4 inhibition enhances anti-melanoma effects of BRAF/MEK inhibition
Authors: Zhang Yanping , Hsueh Eddy C. 
Published: July 2017

Abstract
Introduction: Targeted therapy against BRAF-mutated melanoma has shown clinical efficacy. However, resistance to therapy often occurs. CDK4 (INK4)-retinoblastoma (RB) pathway controls cell cycle progression by regulating the G1-S checkpoint. Defect in the p16INK4A: cycling D-CDK4/6: RB pathway is also detected in melanoma. We study the effect of combining CDK4-RB pathway inhibition with BRAF/MEK inhibition as a possible strategy to overcome resistance to therapy.
Methods: Three BRAF wild-type and three BRAF-mutated melanoma cell lines were selected. CDK4/6 inhibitor (PD0332991; PD), BRAF inhibitor (PLX4032; PLX), MEK inhibitor (AZD6244; AZD), and PI3K/AKT inhibitor (XL765; XL) were used alone or in combination. Cell proliferation assay was performed using Cell Titer Blue assay. Cell migration assay was performed by artificial wounding of melanoma cell monolayer and observing migration of cells into the wound up to 48 hours. Western blotting was performed for expression of pERK/ERK, pRB/RB, Cyclin D1, CDK4, and GAPDH. Data were presented as means ± SD for triplicate experiments. For comparison between groups, the student’s t test was used and p&lt;0.05 was considered to be statically significant.
Results: Variable inhibition of cell proliferation and migration was observed in a dose- and time-dependent fashion. Enhanced inhibition of melanoma proliferation and migration was observed with PD+AZD and PD+PLX combination compared with single agent AZD or PLX. Differential enhancement was observed in BRAF wild-type cell lines with PD+AZD and in BRAF mutated cell lines with PD+PLX combination. Minimal change in tumor proliferation and migration inhibition was noted with PD+XL combination compared with PD or PLX alone. No correlation was observed between expression of CDK4 and cyclin D1 and sensitivity to singe agent or the combination. Inhibition of phosphorylated RB1 and ERK expression was observed with exposure to single agent PD, PLX, XL, AZD. Enhancement of pRB1 and pERK inhibition was noted with PD+PLX and PD+AZD combination but not PD+XL.
Conclusion: CDK4 inhibition can enhance anti-proliferation and migration effects of BRAF/ MEK inhibition in melanoma cells. The mechanism is via augmented down-regulation of pRB expression.
Citation Format: Yanping Zhang, Eddy C. Hsueh. CDK4 inhibition enhances anti-melanoma effects of BRAF/MEK inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2345. doi:10.1158/1538-7445.AM2017-2345
Abstract 2352: Effect of inhibition of cell cycle versus transcription cyclin-dependent kinases (CDKs) in ovarian cancer cells
Authors: Chilà Rosaria , Panini Nicolò , Erba Eugenio , Damia Giovanna , Broggini Massimo 
Published: July 2017

Abstract
Background. Cell cycle is regulated by cyclin-dependent kinases (CDKs) activity, whose deregulation can lead to uncontrolled proliferation and cancer. Other CDKs are engaged in the regulation of transcription and post-transcriptional mRNA processing through the phosphorylation of the C-terminal domain of RNA polymerase II, such as CDK9 and CDK12. Inhibitors of cell cycle CDKs have been developed as anticancer agents and some of them are under clinical validation (e.g. palbociclib). While recent data would suggest that inhibition of CDK9 is feasible and has antitumor effect, the data on the therapeutic role of CDK12 inhibition are very scanty.
Methods. Ovarian cancer cell lines were maintained in RPMI medium supplemented with 5% glutamine and 10% FBS. Cells were treated with different drug concentrations and after 72 hours cell survival was evaluated by MTS assay (Promega). IC50 values were calculated by interpolation method. Cell cycle analysis and apoptosis were performed with standard flow cytometric methods. A2780 and SKOV3 ovarian cancer cell lines knocked out for CDK12 were generated with CRISPR/CAS9 genome editing tool.
Results. The cytotoxicity of palbociclib (a CDK4/6 inhibitor) and LDC000067 (a CDK9 inhibitor) was tested in a panel of ovarian cancer cell lines (A2780, SKOV3, OVCAR3, OVCAR5, OVCAR8, OVCA432, OVCA433, IGROV1, EFO27). Sensitivity of cells was similar for palbociclib and LDC000067, ranging from 10 to 33 and from 8 to 60 μM, respectively. A preferential G1 block was observed with palbociclib, while LDC000067 caused a S-G2 block. A higher induction of apoptosis was observed after LDC000067 than after palbociclib treatment in both A2780 and SKOV3. The palbociclib-induced G1 block was associated with decreased Rb phosphorylation, while no modulation of the Ser2 in the carboxyterminal domain of RNA polymerase II was observed after LDC000067 treatment. We generated CDK12 knocked out cells transfecting CRISPR/CAS9 engineered plasmid in both A2780 and SKOV3 ovarian cancer lines. The biological and pharmacological characterization of these clones is under study.
Conclusions. Palbociclib and LDC000067 showed a dose dependent cytotoxic effect in the panel of ovarian cancer cell lines tested and were active in the μM range. Preliminary data of treatment induced cell cycle perturbation and apoptosis suggest that the two drugs behave in a different manner and have distinct molecular effects on cells.
Citation Format: Rosaria Chilà, Nicolò Panini, Eugenio Erba, Giovanna Damia, Massimo Broggini. Effect of inhibition of cell cycle versus transcription cyclin-dependent kinases (CDKs) in ovarian cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2352. doi:10.1158/1538-7445.AM2017-2352
Abstract 2353: CDKI-15, a novel and highly selective CDK4/6 inhibitor: discovery, in vitro and in vivo anticancer efficacy
Authors: Tadesse Solomon , Bantie Laychiluh , Tomusange Khamis , Islam Saiful , Rahaman Muhammed H. , Noll Benjamin , Lam Frankie , Yu Mingfeng , Wang Shudong 
Published: July 2017

Abstract
Cyclin D dependent kinases CDK4 & CDK6 are crucial regulators of the G1 to S phase transition of the cell cycle. The facts that myriad cancer types show aberrance in INK4-CDK4/6-cyclin D-Rb-E2F pathway, & the rapidly emerging positive clinical data of pharmacological inhibitors have validated CDK4/6 as anticancer drug targets. As the first commercialized CDK inhibitor, palbociclib in combination with letrozole or fulvestrant has received regulatory approval for the treatment of breast cancer. This represents an important scientific advance in the field. However, the limited structural diversity & undesired side effects due to broader kinase interactions of existing inhibitors mean that the hunt for new & highly selective CDK4/6 inhibitor drug candidates continues. Using our advanced medicinal chemistry, targeted biochemical & cell-based assays, & animal pharmacology, we synthesized & evaluated a novel series of inhibitors. Many compounds were highly potent & selective against CDK4/6, & exhibited low nanomolar potency against a range of human cancer cell lines. Notably, inhibition of CDK4D1 by compound CDKI-15 (Ki = 4 nM) was over 3 orders of magnitude greater than CDK1B, CDK2A, CDK7H & CDK9T1. Interrogation of a panel of 369 protein kinases revealed CDKI-15 to be highly selective for CDK4/6 with only 3 other kinases inhibited potently. CDKI-15 reduced the level of Rb phosphorylation & induced G1 cell cycle arrest, confirming cellular inhibition of CDK4/6 in cancer cells. Moreover, CDKI-15 possesses superior pharmacokinetic profile with oral bioavailability of 100% in mice. Treatment of nude BALB/c mice bearing human MV4-11 acute myeloid leukemia cells with CDKI-15 at daily dose of 100 mg/kg by oral administration resulted in a robust inhibition of tumor growth compared to vehicle treated animals (T/C = 30%, p &lt; 0.00001). Strikingly, CDKI-15 caused a complete & sustained tumor regression in one-third of the animals. No detectable toxicity was observed in the animals during & post treatment. Taken together, our data provide a rationale for CDKI-15 to be developed towards clinic for cancer therapy.
Citation Format: Solomon Tadesse, Laychiluh Bantie, Khamis Tomusange, Saiful Islam, Muhammed H. Rahaman, Benjamin Noll, Frankie Lam, Mingfeng Yu, Shudong Wang. CDKI-15, a novel and highly selective CDK4/6 inhibitor: discovery, in vitro and in vivo anticancer efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2353. doi:10.1158/1538-7445.AM2017-2353
Abstract 2354: Identification of CDK1 as an aspirin and salicylic acid binding protein: a potential role in chemoprevention
Authors: Gunaje Jayarama B. , Kumar D.Ramesh , Kesharwani Siddharth , Callegari Eduardo , Tummala Hemachand , Dachineni Rakesh 
Published: July 2017

Abstract
Data emerging from the past 10 years have consolidated the rationale for investigating the use of aspirin for chemoprevention; however, the mechanisms leading to its anti-cancer effects are still being elucidated. We hypothesized that aspirin’s ability to exert chemopreventive effects may involve altering the levels and activity of cell cycle regulatory proteins. In the present study, using HT-29 colon cancer cells and other cancer cells, we demonstrated that both aspirin and its primary metabolite, salicylic acid, downregulated the protein and mRNA levels of cyclin B1 and cyclin dependent kinase-1 (CDK1). Lactacystin, a 26S proteosomal inhibitor, prevented aspirin and salicylic acid mediated degradation of cyclin B1, but not CDK1. Decrease in protein levels of cyclin B1/CDK1 was correlated with a corresponding decrease in CDK1 kinase activity. Molecular docking studies showed that aspirin and salicylic acid independently can dock on CDK1 through interactions with Leucine 83. Incubation of recombinant CDK1 with aspirin resulted in acetylation at lysine residues, this was also observed in cell culture experiments. Pre-incubation of CDK1 with salicylic acid dose dependently prevented aspirin’s ability to acetylate CDK1 in purified preparations confirming the data obtained from molecular docking studies. Our results show that CDK1 is a salicylic acid binding protein (SABP) and the chemopreventive actions of aspirin may involve modulation of levels and activity of cyclin B1 and CDK1.
Citation Format: Jayarama B. Gunaje, D.Ramesh Kumar, Siddharth Kesharwani, Eduardo Callegari, Hemachand Tummala, Rakesh Dachineni. Identification of CDK1 as an aspirin and salicylic acid binding protein: a potential role in chemoprevention [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2354. doi:10.1158/1538-7445.AM2017-2354