bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 1538: Role of mitochondrial dysfunction in GPX regulation and glutathione metabolism
Authors: Lu Weiqin , Feng Li , Zhang Hui , Huang Peng 
Published: February 2011

Abstract
Many cancer cells exhibit mitochondrial respiratory dysfunction, which is associated with metabolic alterations, change in cellular redox states, and drug resistance. It is also known that elevated glutathione in cancer cells may promote their survival and resistance to anticancer agents. However, the exact relationship between mitochondrial dysfunction and alterations in cell redox states and viability remain elusive, and the underlying regulatory mechanisms are unclear. In this study, we used a dominant negative form of mitochondrial DNA polymerase γ (POLGdn) expressed in a T-Rex293 tet/on system as a model to induce mitochondrial dysfunction, and showed that suppression of mitochondrial respiration caused a significant increase in ROS generation. Mitochondrial dysfunction also led to a significant increase in glutathione, along with an elevated expression of its rate-limiting enzyme GCLC and the upstream transcription factor Nrf-2. Interestingly, the mRNA expression of glutathione peroxidases GPX1 and GPX4 remain the same, while the GPX proteins and enzyme activity were significantly increased in the mitochondrial defective cells. Since GPX1 and GPX4 are selenium-containing enzymes, they require selenocysteine-tRNA for their protein synthesis. We further demonstrated that selenocysteine-tRNA expression and its transcription factor ZNF143 protein were significantly increased after induction of mitochondrial dysfunction. Furthermore, siRNA knockdown of ZNF143 led to a decrease of GPX activity, an increase in ROS, and a reduction in cell viability in the mitochondrial defective cells. Similarly, a knockdown of GPX1 by shRNA in the mitochondrial defective cells also compromised cell survival. We also observed that ZNF143 protein level was decreased in the GPX1-knockdown cells, suggesting that GPX1 has a positive feedback role in regulating ZNF143 expression. These data suggest that mitochondrial dysfunction led to an activation of glutathione synthesis and an increase in GPX activity through upregulation of the transcription factors Nrf-2 and ZNF143, respectively, and that mitochondrial dysfunction in cancer cells seems to set a new balance between the increase in ROS generation and the elevation in glutathione antioxidant system to maintain cell survival. As such, targeted inhibition of selenocysteine-tRNA, selenoenzymes, or glutathione synthesis may be potential therapeutic strategies for cancer treatment.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1538.
Abstract 1540: MAPK signaling profiles differ between 1,25D-sensitive HL60G and 1,25D-resistant 40AF human leukemia cells
Authors: Chen-Deutsch Xiangwen , Studzinski George P. 
Published: February 2011

Abstract
The resistance to 1,25-dihydroxyvitamin D3 (1,25D) could be an obstacle for potential clinical use of vitamin D in differentiation therapy of leukemia. 40AF cells are a subline of HL60 cells and provide a model for studies of 1,25D-resistance. It is known that 40AF cells grow more rapidly than the parental cells, and have a high percentage of cells in S phase. Also, the addition of the plant antioxidant carnosic acid and a kinase inhibitor SB202190 (the combination dubbed DCS) can partially overcome the resistance to 1,25D. To better understand the basis for this resistance we examined MAPK network profiles, previously shown to be important for HL60 cell differentiation, on mRNA level by RT2-PCR arrays. The results showed that 17 out of 84 genes studied had significantly altered mRNA levels (more than 2 fold) in 40AF cells compared to HL60G cells. Eighteen genes had lower basal level of expression in 40AF compared to HL60G cells, and after partial reversal of resistance by DCS treatment these genes showed increased expression; in contrast, 20 genes had higher basal levels in 40AF cells and their expression was decreased by DCS, suggesting that these genes may be involved in 1,25D resistance. Also, DCS treatment of 40AF cells changed the expression of the RAS-ERK pathway components more obviously than the JNK and the p38MAPK pathways. Mitotic cyclins and CDKs had a generally enhanced expression in 40AF cells compared to HL60G, and their expression decreased following DCS treatment, consistent with the slow down of the cell cycle by DCS, perhaps also because several CKIs, including p21Cip1, dramatically increased. Studies using Phospho-MAPK arrays showed that treatment of both HL60G and 40AF cells with 1,25D or DCS altered the levels of phosphorylated proteins of MAPK family members P-ERK2 in the ERK pathway, P-JNK2 in the JNK pathway, P-p38 alpha/delta/gamma in the p38 pathway, P-Akt1 in the PI3/Akt pathway. The gene expression studies will be validated by Westerns, and MAPK activity by kinase assays. In summary, MAPK signaling networks may play important roles in 1,25D resistance in AML cells, and modification of network expression can influence cell cycle progression and cell differentiation to partially reverse the resistance to 1,25D of non-responding leukemia cells.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1540.
Abstract 1541: Role of GSH in mediating stromal-leukemia interaction and promoting cell survival and drug resistance in chronic lymphocytic leukemia
Authors: Zhang Wan , Trachootham Dunyaporn , Liu Jinyun , Keating Michael J. , Huang Peng 
Published: February 2011

Abstract
Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the western countries. The interaction between CLL cells and the bone marrow stromal environment is thought to play a major role in promoting the leukemia cell survival and drug resistance. Here we show a novel biochemical mechanism by which the bone marrow stromal cells exert a profound influence on the redox status of primary CLL cells and enhance their ability to sustain oxidative stress and drug treatment. Fresh leukemia cells isolated from the peripheral blood of CLL patients exhibited two major redox alterations when they were cultured alone: a significant decrease in cellular glutathione (GSH) and an increase in basal ROS levels. However, when cultured in the presence of bone marrow stromal cells, CLL cells restored their redox balance with an increased synthesis of GSH, a decrease in spontaneous apoptosis, and an improved cell survival. Further study showed that CLL cells were under intrinsic ROS stress and highly dependent on GSH for survival, and that the bone marrow stromal cells promoted GSH synthesis in CLL cells through a novel biochemical mechanism. Cysteine is a limiting substrate for GSH synthesis and is chemically unstable. Cells normally obtain cysteine by uptaking the more stable and abundant precursor cystine from the tissue environment and convert it to cysteine intracellularly. We showed that CLL cells had limited ability to take up extracellular cystine for GSH synthesis due to their low expression of the transporter Xc-, but had normal ability to uptake cysteine. In the co-culture system, the bone marrow stromal cells effectively took up cystine and reduced it to cysteine for secretion into the tissue microenvironment to be taken up by CLL cells for GSH synthesis. The elevated GSH in CLL cells in the presence of bone marrow stromal cells significantly protected the leukemia cells from stress-induced apoptosis, and rendered them resistant to standard therapeutic agents such as fludarabine and oxaliplatin. Importantly, disabling of this protective mechanism by depletion of cellular GSH using a pharmacological approach potently sensitized CLL cells to drug treatment, and effectively enhanced the cytotoxic action of fludarabine and oxaliplatin against CLL in the presence of stromal cells. This study reveals a key biochemical mechanism of leukemia-stromal cells interaction, and identifies a new therapeutic strategy to overcome drug resistance in vivo.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1541.
Abstract 1542: Molecular mechanisms associated with sensitivity/resistance to PM02734 (Irvalec®), a novel marine-derived cyclic depsipeptide
Authors: Serova Maria , Bieche Ivan , Vidaud Michel , Aracil Miguel , Faivre Sandrine , Raymond Eric 
Published: February 2011

Abstract
Background: PM02734 (Irvalec®) is a novel synthetic depsipeptide derived from kahalalide F currently in clinical trials with evidence of antitumor activity. This study aimed to evaluate the mechanisms yielding antiproliferative effects of PM02734 in human cancer cells.
Materials and Methods: Antiproliferative effects of Irvalec used MTT assay. Baseline and phosphorylated protein levels were assessed using Western blot. Relative level of mRNA expression was evaluated using quantitative qRT-PCR.
Results: PM02734 displayed antiproliferative effects in a panel of 20 cancer cell lines with IC50s ranging 0.4-9µM in breast (ZR-75-1, SKBR3 and MDA-MB-361) and colon (Colo205 and HCC2998) cancer cell lines. Unspecific changes were observed in MAPK and AKT intracellular signaling under exposure to PM02734 despite a decreased Erb-B3 mRNA expression and Erb-B3 phosphorylation at 24h. To study mechanisms associated with resistance to PM02734, we developed DU-PM cells using stepwise exposures to increasing concentrations of PM02734 in DU145. After &gt;6 months exposure to PM02734, DU-PM cells were 4-fold more resistant to PM02734 than parental DU145 cells. Resistance was associated with decreased mRNA expressions of Erb-B3/Erb-B4 and vimentin. Conversely, the mRNA expressions of anti-apoptotic genes such as CDKN1A/p21 and BCL2 were significantly increased in PM02734-resistant cells. Interestingly, DU-PM cells were more sensitive to EGFR inhibitors such as erlotinib, gefitinib and lapatinib than parental DU145 cells. These results provide a rational basis for for further exploring PM02734 in combination with EGFR inhibitors in solid tumors.
Conclusions: PM02734 displays antiproliferative effects against a large variety of cancer cell lines at pharmacological concentrations. Acquired resistance to PM02734 associated with low Erb-B3 expression that may be regarded as predictive factor of sensitivity. The cells with acquired resistance to PM02734 display increased sensitivity to EGFR inhibitors.
Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1542.
Abstract 1558: STX140 but not paclitaxel inhibits mammary tumor initiation, progression and metastasis in C3(1)/SV40 T/t-antigen transgenic mice
Authors: Foster Paul A. , Newman Simon P. , Day Joanna M. , Leese Matthew P. , Potter Barry VL , Reed Michael J. , Purohit Atul 
Published: February 2011

Abstract
New chemotherapeutic options for late-stage metastatic breast cancer are urgently required. Currently, the taxanes are considered one of the most effective treatments for late-stage cancer treatment.
Paclitaxel and the novel cytotoxic agent STX140, compounds that have shown significant activity against numerous xenograft mouse models of cancers, are here investigated in the C3(1)/SV40 T/t-antigen mouse model of spontaneous breast cancer. This mouse model recapitulates important histopathological and molecular alterations in mammary cancer development over a highly predictable time-course. At 8 weeks of age, the female animals develop low-grade mammary intra-epithelial neoplasia (MIN) lesions. By 12 to 14 weeks of age this progresses to high-grade MIN, which is similar to human ductal carcinoma in situ. From 15 weeks of age onwards invasive, metastatic carcinomas are observed. STX140 and paclitaxel were administered to these mice at 12 weeks of age (early intervention) and when tumors had reached 0.5 cm (late intervention).
Results demonstrated that all mice in the control and paclitaxel treated groups at early intervention developed palpable mammary cancer which grew to 3112 mm3 by 25 weeks of age and led to the termination of these animals at week at this time point. However, STX140, when administered at week 12 onwards, blocked disease progression and no palpable tumor develop in 47% of tumors and significantly inhibited the growth of tumors that did develop. This resulted in a significant (P &lt; 0.01) survival advantage for animals treated with STX140. Conversely, in C3(1)/SV40 mice, paclitaxel failed to inhibit tumor growth and therefore did not confer a survival benefit. In the late treatment groups, STX140 significantly (P &lt; 0.05) inhibited primary mammary cancer growth and also resulted in a significant (P &lt; 0.001) survival advantage compared to control animals. Furthermore, it was observed that paclitaxel treatment increased liver metastases in these mice.
To conclude, STX140 has a greater anti-cancer efficacy and conferred an improved survival outcome compared to paclitaxel in a clinically relevant transgenic mouse model of metastatic breast cancer.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1558.
Abstract 1561: Guaiacol glyceryl ether, a novel agent to reduce MUC1 expression in breast cancer cells
Authors: Smith Joshua S. , Colon Jimmie , Madero-Visbal Rafael , Konduri Santhi , Baker Cheryl H. 
Published: February 2011

Abstract
Purpose: The overexpression and loss of polarity of Mucin1 (MUC1) has been documented in aggressive breast cancer. We have identified guaifenesin as a novel treatment to reduce or eliminate MUC1 expression on human breast cancer cells.
Methods: MCF-7 and ZR-75-1 human breast cancer cells were grown for 48 hours in varying concentrations of guaifenesin to determine if a dose dependent effect on MUC1 protein expression resulted with treatment. In addition, cells were also harvested, RNA isolated, reverse transcribed and PCR was performed using ABI quantitative real time PCR machine. In another set of experiments, MCF-7 cells were plated and grown for 72 hours in the absence or presence of 12.5 mM guaifenesin and the cells were harvested and stained with propidium iodine for analysis by flow cytometry. The Cell-Titer Glo assay was performed on MCF-7 and ZR-75-1 cells incubated for 48 hours in the presence of guaifenesin at varying concentrations and the LD50 was determined. In a final set of experiments, MCF-7 cells, incubated in the presence or absence of guaifenesin, were analyzed for their ability to migrate /proliferate in vitro by using a standard scratch assay. For in vivo studies ovarectomized female nude mice were injected with MCF-7-luciferase tagged cells into the mammary fat pad 24 hours after an estrogen pellet was implanted into the right flank. Treatment (vehicle or 400 mg/kg/daily) was initiated after 10 days and tumor growth was monitored through Kodak imaging system. Six weeks after the treatment tumors were isolated, measured and processed for immunohistochemistry to analyze the expression of MUC1, TUNEL and CD31.
Results: Initially, MUC1 gene expression was confirmed in MCF-7 and ZR-75-1 human breast cancer cell lines. Following confirmation, the LD50 was determined to be 12.5 mM. MUC1 gene expression was successfully decreased in a dose-dependent manner in both MCF-7 and ZR-75-1 cell lines when treated with guaifenesin. When MCF-7 cells are treated with 12.5mM guaifenesin, G1 arrest occurs within 24 hours and by 72 hours, 94.2% of cells are in G1 compared to 76.2% in control (drug free) conditions. In addition, there was a significant decrease in the ability of guaifenesin treated MCF-7 cells to migrate into the scratch compared to the control (untreated) cells. In vivo studies revealed that guaifenesin significantly decreased the breast tumor weight and volume which was associated with a low expression of MUC1 in tumor sections as evaluated by immunohistochemistry.
Conclusion: These findings suggest that guaifenesin may provide a novel approach to inhibit breast cancer growth.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1561.
Abstract 1563: Role of EGFR during the transition of inflammation to dysplasia in a colitis-associated colon cancer model
Authors: Pagan-Ortiz Beatriz , Isidro Angel A. , Coppola Domenico , Wu Jie , Appleyard Caroline B. 
Published: February 2011

Abstract
Background: The underlying mechanisms in ulcerative colitis-associated dysplasia are poorly understood. Neurokinin-1 receptors (NK-1R) have been shown to be involved in chronic colonic inflammation, and we have demonstrated their over-expression in patients with dysplasia. The NK-1R has been found to crosstalk with the epidermal growth factor receptor (EGFR). EGFR is related to the development of some cancers including colorectal cancer. Erlotinib, a potent inhibitor of the EGFR tyrosine kinase, has been shown to inhibit the intracellular EGFR signaling pathway and to block non-small cell lung cancer and pancreatic tumor growth; however its role in the genesis of dysplasia is unknown. Aim: The aim of this study was to investigate the role of EGFR in a novel model of colitis-associated dysplasia using a small molecule inhibitor, Erlotinib. Methods: Sprague Dawley rats received trinitrobenzene sulfonic acid (TNBS; 30 mg in 50% ethanol, ic.), followed six weeks later by reactivation with TNBS (5 mg/kg, iv.) for three days. To induce colitis-associated dysplasia, the rats then received TNBS (iv.) twice a week for ten weeks. One group received the Erlotinib (10 mg/kg, ip.) for one week before the start of the reactivation of the colitis and two weeks after (21 days); the rest received the vehicle. After sacrifice, the colons were removed and analyzed for damage and expression of NK-1R, Cox-2, EGFR, and the downstream signaling components. Results: Animals receiving Erlotinib had no significant difference in macroscopic or microscopic damage from controls. Pathological analysis however revealed a decrease of the incidence of dysplasia in animals treated with Erlotinib when compared with the vehicle-treated animals. This decrease was most evident in both the mid and the distal colon (15% vs. 53% and 20% vs. 61%). Colonic tissues from Erlotinib-treated animals also had decreased expression of NK-1R, Cox-2, pErk ½, and Akt compared to the vehicle-treated group. Conclusion: Our results suggest that Erlotinib can delay the development of colitis associated dysplasia, suggesting a potential therapeutic use for Erlotinib in patients with long-standing colitis. Supported in part by 1U56 CA126379-01 and 1F31 GM078951.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1563.
Abstract 1571: Nek2 as an effective molecular target for cancer treatment
Authors: Kokuryo Toshio , Senga Takeshi , Yokoyama Yukihiro , Nagino Masato , Hamaguchi Michinari 
Published: February 2011

Abstract
Nek2 (NIMA-related kinase 2) is a member of the serine/threonine kinase family, Nek, structurally related to the essential mitotic regulator NIMA. Nek2 is involved in cell division and mitotic regulation by centrosome splitting. Increased expression of Nek2 has been reported in cell lines derived from cervical and prostate cancer as well as lymphomas. We, therefore, examined the expression levels of Nek2 in various cancer cell lines, such as cholangiocarcinoma (HuCCT1, TFK1, HuH28, CCKS1, ETK1, RBE, IHGGK), breast cancer (BT20, BT474, Hs578T, MCF7, MDA-MB-231, T47D, ZR-75-1) and colorectal cancer (HCT-15, DLD-1, Colo205, Colo320). These cancer cells expressed higher levels of Nek2 mRNA and protein than those of HFF, a cell line derived from normal human fibroblast. The expression of Nek2 was also elevated in breast cancer and colorectal cancer tissue in compared with that of normal tissue. The Nek2 suppression with siRNA resulted in the inhibition of cell proliferation and induced cell death in these cancer cell lines. We next examined the effect of Nek2 siRNA treatment on the growth of cholangiocarcinoma tumor in xenograft-nude mouse model. Mean tumor volumes in Nek2 siRNA-treated mice were substantially reduced in comparison with those of the control mice. The Nek2 expression in the tumor tissues was dramatically suppressed in Nek2 siRNA treated tumors, as compared with those of control siRNA treated tumors. Nek2 siRNA also resulted in reduction of tumor size as compared with those of control siRNA injection in breast cancer tumor and colorectal cancer tumor. To further evaluate the effects of Nek2 siRNA treatment, we challenged siRNA in the peritoneal dissemination model. It should be noted that peritoneal dissemination is one of the major undesirable complications frequently associated with inoperable cases. In peritoneal dissemination model, Nek2 siRNA-treated mice showed statistically longer survival periods in comparison with those of the control siRNA-treated mice. Survival rates of the Nek2 siRNA-treated mice were approximately 1.5 times higher than those of the control siRNA-treated mice. Taken together, for the improvement of cancer therapy, identification of specific molecular targets critical for its tumorigenicity is an important issue. Nek2 plays a critical role in tumorigenic growth of various cancers, and inhibition of Nek2 expression with its siRNA causes suppression of cancer growth and survival. Our data in vivo provides a strong rationale for the further investigation of Nek2 inhibitors as a new cancer therapy, holding the potential to provide regression of multiple human malignancies.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1571.