bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1239: Smurf2-mediated ubiquitination and degradation of Id1 regulates p16 expression during senescence
Authors: Kong Yahui , Zhang Hong
Published: June 2012

The cyclin-dependent kinase inhibitor p16INK4A (p16) plays a critical role in senescence, cancer and aging. Its expression increases in senescent cells and with aging in many tissues of rodents and humans. The regulation of p16 expression during senescence and aging is of great interest, but is not well understood. Here we report that Smurf2, an E3 ubiquitin ligase previously found to activate senescence, can regulate p16 expression during senescence. We find that Smurf2 is required for the elevation of p16 in senescent cells, while ectopic expression of Smurf2 is sufficient to induce p16 expression dependent on its E3 ligase activity. This ligase-dependent regulation of p16 contrasts with previously identified ligase-independent regulation of p21 by Smurf2. Interestingly, we find that Smurf2 expression increases with aging in a number of tissues in mouse, providing a possible mechanism of increased p16 expression during aging. Furthermore, we identify Id1, a transcriptional repressor of p16, as a novel ubiquitination target of Smurf2's E3 ligase activity. Ubiquitination and degradation of Id1 by Smurf2 is the mediator through which Smurf2 regulates p16 expression. As the expression of Smurf2 increases in senescent cells in response to telomere shortening, our finding provides a possible link between telomere shortening and p16 expression during senescence. Further, the regulation of p16 by Smurf2 through Id1 ubiquitination and degradation will help us to understand the underlying mechanism of senescence provoked by Smurf2, and provide insight into tumor suppression or aging regulated by Smurf2.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1239. doi:10.1158/1538-7445.AM2011-1239
Abstract 1242: Induction and targeting of polyploid senescent cells in cancer therapeutics
Authors: Wang Qin , Wu Peter , Ivanova Iana , Chu Elizabeth , Wu Daniel Y.
Published: June 2012

Therapy-induced cellular senescence (TCS), an emerging concept in cancer therapeutics, describes an in vivo response of human tumors to chemotherapy and radiation. These treatments elicit a coordinated response that results in prolonged cell cycle arrest, characteristic senescence morphology and expression of senescence-specific markers. In the past decade, a growing body of evidence has supported the hypothesis that “senescence response occurs in treated human cancers and the response is reversible.” We now present evidence that TCS may be adverse to cancer therapeutics based on a clinicopatholgical study conducted in patients with advanced non-small cell lung cancer following induction therapy prior to surgery. To further define how a subpopulation of senescent cells could escape terminal arrest, our work now implicates a polyploid state through which senescent cells can survive and eventually resume proliferation. In H1299 lung cancer cells, we show that mitotic kinase Cdk1 facilitates endoreplication and formation of polyplid senescent cells (PSCs) following chemotherapy as the genetic modulation of Cdk1 activity profoundly affect the prevalence of these polyploid cells. Importantly, senescence escape occurs from the PSCs at 2.5 times the frequency of escape observed from diploid (2/4n) cells through novel non-canonical cell division mechanisms. Furthermore, we also demonstrate distinct functions of p21 and p27, two members of KIP family in TCS. While both interact with endogenous cyclin B1-Cdk1 complex in senescent cells, only p27 directly inhibits Cdk1 kinase activity and modulates PSC formation, whereas the knockdown of p21 leads to massive apoptosis. Finally, we show that statins, HMG-CoA inhibitors, currently approved for treatment of dyslipidemia down-regulate several key targets of the Cdk1 pathway, including Cdk1 itself, cyclin B1, and survivin, while up-regulating p27. Statins both decrease polyploid cells and abrogate escape of several cancer cell lines from TCS. Altogether, our work here challenges the current cancer treatment paradigm and supports the incorporation of novel strategies to enforce irreversible cell cycle exit in senescent tumor cells following treatment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1242. doi:10.1158/1538-7445.AM2011-1242
Abstract 1244: The requirement of autophagy pathway for drug-induced senescence in human melanoma cells by AZD1152
Authors: Zhang Gao , Herlyn Meenhard
Published: June 2012

Oncogene-induced senescence (OIS) is a well-documented phenomenon both in vitro and in vivo as a tumor-suppression mechanism. It functions as a barrier to tumor initiation and progression. However, tumor cells quickly develop a sophisticated yet not well-understood mechanism to overcome and subsequently repress cellular senescence to facilitate its progression. Here we have focused on the drug-induced senescence in human melanoma cells by inhibition of Aurora B kinase (AURKB) through either small molecule AZD1152 or shAURKB. By implementing a systems biology approach, we have uncovered the necessity of mTOR, and autophagy/lysosome pathways for the drug-induced senescence in human melanoma cells. Particularly, the mTOR inhibitor Rapamycin suppresses the senescence phenotype by converting senescence to quiescence, whereas the autophagy inhibitor Bafilomycin A1 or Hydroxychloroquine can induce cell death in senescent melanoma cells induced by AZD1152, suggesting that autophagy is an important survival mechanism for senescent melanoma cells. Thus our study can potentially lead to a framework of utilizing the pro-senescence therapy followed by inhibition of autophagy as a novel clinic approach toward melanoma prevention and cure.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1244. doi:10.1158/1538-7445.AM2011-1244
Abstract 1283: Phase I and pharmacokinetic evaluation of the DNA methyltransferase inhibitor 5-fluoro-2′-deoxycytidine: A California Cancer Consortium study
Authors: Newman Edward M. , Morgan Robert J. , Beumer Jan H. , Blanchard Suzette M. , El-Khoueiry Anthony B. , Kummar Shivaani , Carroll Mary I. , Synold Timothy W. , Lenz Heinz J. , Doroshow James H.
Published: June 2012

Background: The California Cancer Consortium conducted the first-in-human clinical trial of the investigational new drug 5-fluoro-2′-deoxycytidine (FdC), a DNA methyltransferase inhibitor stable in aqueous solution, as a 3-hour infusion concurrent with 350 mg/m2 of the cytidine deaminase inhibitor tetrahydrouridine (THU), included to prolong the half-life of FdC in vivo. Methods: A 3+3 design was used; initial FdC dose doubling ended when two moderate toxicities or one severe toxicity were observed. Pharmacokinetics of FdC and THU were obtained. Results: On the initial schedule, daily (QD) × 5 every 21 days (d), FdC was escalated from 2.5 to 80 mg/m2/d without treatment-related grade 3 toxicity other than anemia and lymphopenia. At FdC doses ≥20 mg/m2/d, peak plasma FdC concentrations were above those that inhibit DNA methylation in vitro (Beumer, et al., Cancer Chemother Pharmacol 62:363-8, 2008). The schedule was amended to QD × 5 for 2 consecutive weeks every 28 d, and patients (pts) were enrolled at 40, 67, 100, 134, and 180 mg/m2/d. Overall, 51 pts were treated [28 M; 23 F; median (range): age 63 (30-85), KPS 80 (60-100)]; 44 pts were evaluable for toxicity (1 cycle). 1/6 pts at 134 mg/m2/d had dose-limiting toxicity (DLT) (grade 3 colitis) and 2/2 pts at 180 mg/m2/d had DLT (1-grade 3 fatigue + LFT; 1-grade 4 mucositis + ANC + platelets). Of the 31 pts on 28-d cycles, 8 had clinical progression prior to the first scheduled evaluation at 8 weeks and 5 did not complete 2 cycles for other reasons; 7 pts had progressive disease at 8 weeks; and 10 pts had stable disease for ≥8 weeks. In addition, 1 heavily-pretreated pt with breast cancer, treated at 67 mg/m2/d, had a partial response lasting 1 year. Conclusions: The Maximum Tolerated Dose was 134 mg/m2/d FdC + 350 mg/m2/d THU QD × 5 for 2 consecutive weeks every 28 d. An expansion cohort is being accrued to determine the pharmacokinetics of oral FdC and THU. Based on the nature of the toxicities and the observed response at 67 mg/m2/d, a multi-histology Phase II trial has been initiated at 100 mg/m2/d QD × 5 for 2 consecutive weeks every 28 d. Supported by U01 CA62505, P30 CA33572, N01-CM-52202, and P30CA47904. The authors acknowledge the invaluable contribution of Dr. M. J. Egorin.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1283. doi:10.1158/1538-7445.AM2011-1283
Abstract 1295: Relationship between pharmacokinetic (PK) sampling schema and reported PK variability of liposomes in patients
Authors: Schell Ryan F. , Caron Whitney P. , Walsh Mark D. , Zamboni Beth A. , Ramanathan Ramesh K. , Zamboni William C.
Published: June 2012

Introduction: Liposomal formulations offer advantages over small molecules including increased solubility, selective targeting potential and prolonged drug exposure. Compared with conventional formulations, these agents often have greater PK and pharmacodynamic variability, which is attributed to the role of the mononuclear phagocyte system in the clearance of liposomes. Inter-patient variability in drug exposure, represented by area under the curve (AUC), of encapsulated drug can be 20- to 100-fold. However, some nanoparticle and liposomal agents report lower inter-patient PK variability. Study design and sampling schema may affect the documentation of PK variability, due to the prolonged systemic exposure of encapsulated drug. Thus, we evaluated the reported PK variability of PEGylated CKD-602 (S-CKD602) and non-liposomal CKD-602 (NL-CKD-602) using a short (0-24 h) and long (0-336 h) sampling schema.

Methods: S-CKD602 and NL-CKD-602 were administered at doses ranging from 0.5 to 2.1 mg/m2 in phase I studies of patients with advanced solid tumors. Blood samples were obtained from baseline to 336 h for S-CKD602 and from baseline to 24 h for NL-CKD-602. Plasma concentration of total (lactone + hydroxy acid) encapsulated CKD-602 from S-CKD602 and total CKD-602 from NL-CKD-602 were measured by LC-MS/MS. AUC from 0 to 24 h (AUC0-24) and 0 to 336 h (AUC0-336) were calculated. The coefficient of variance % (CV%) in AUC0-24 and AUC0-336 at each dose level were calculated for S-CKD602 and NL-CKD-602. Results:

Conclusion: The inter-patient variability of exposure of S-CKD602 is 2.5- to 3.4-fold greater than that of NL- CKD-602. Current PK study designs limited to 24 h underestimate the inter-patient variability of exposure of S-CKD602. PK study design of liposomal agents requires an extended PK sampling schema to accurately describe its PK disposition. A limited sampling strategy that may be applied for all nanoparticles is under development to address this issue.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1295. doi:10.1158/1538-7445.AM2011-1295
Abstract 1297: DDAIP improves the pharmacokinetic profile of PrevOnco® in different species: Comparison of DDAIP, CMC and PEG-300/400 formulations in mice, beagle dogs and cynomolgus monkeys
Authors: Dines Kevin , Incardona Francesca , Hachicha Mohamed , Martin Richard , Damaj Bassam
Published: June 2012

Our study in the accompanying abstract demonstrates that a low dose of PrevOnco® in combination with doxorubicin was efficacious in a liver cancer model. In this study we investigated the pharmacokinetic profile of PrevOnco® when formulated with 20% DDAIP or 20% PEG-300 in mice, dogs and cynomolgus monkeys. The goal was to evaluate the potential of formulation in DDAIP to increase PrevOnco® exposure in vivo.

Methods: PK plasma analyses of PrevOnco® administered orally at 100 mg/Kg in 1% carboxy methyl cellulose (CMC) or in 10% PEG-400 were evaluated in nude mice. 20% PEG-300 and 20% DDAIP formulations were evaluated in mice (100 mg/Kg), dogs (5 mg/Kg) and monkeys (5 mg/Kg).

Results: Compared to 20% PEG-300, administration of PrevOnco® in 20% DDAIP induced 7-fold, 8-fold and 2-fold improvements in AUC in mice, dogs and cynomolgus monkeys, respectively. In mice, Cmax reached 4,700 ng/mL in DDAIP compared to 1,000 ng/mL in PEG-300 formulation. PrevOnco® levels were detectable up to 4 hours in DDAIP compared to 2 hrs in PEG-300. In dogs, PrevOnco® in 20% PEG-300 formulation had a Cmax of 125 ng/mL at Tmax = 1 hr. This concentration was maintained up to 2 hrs with levels undetectable at 4 hrs. PrevOnco® in 20% DDAIP formulation had a Cmax of 1,600 ng/mL at Tmax=1 hr and T1/2=3hrs. AUC values were 3,941 and 477 for DDAIP and PEG, respectively. In monkeys, PrevOnco® plasma levels following 5 mg/Kg oral administration reached a Cmax of 120 ng/mL in 20% DDAIP and 90 ng/mL in 20% PEG-400. Tmax was 1 hour and 0.5 hour while AUCs were 390 versus 154 (both DDAIP vs. PEG-400).

Conclusion: Formulating with DDAIP increased plasma levels of PrevOnco® following oral administration in mice, dogs and monkeys. Thus, DDAIP facilitated higher Cmax and AUC values as well as a longer T1/2. DDAIP formulation will allow a lower dose of PrevOnco® to be used while maintaining efficacy and reducing cytotoxicity.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1297. doi:10.1158/1538-7445.AM2011-1297
Abstract 1323: Reciprocal regulation of Stat3 and caveolin-1 in normal fibroblasts and breast carcinoma lines
Authors: Geletu Mulu , Mohan Reva , Arulanandam Rozanne , Joshi Bharat , Nabi Ivan Robert , Raptis Leda Helen
Published: June 2012

Membrane tyrosine kinases known to activate the signal transducer and activator of transcription-3 (Stat3) concentrate in caveolae, where they are sequestered in an inactive state through binding to the main caveolae protein, caveolin-1 (cav1). We previously demonstrated that cell-to-cell adhesion can cause a dramatic increase in Stat3 activity in cultured cells. Therefore, to examine the effect of cav1 upon Stat3, experiments were conducted at several confluences. Our results indicate that cav-1 downregulation through expression of anti-sense or shRNA constructs or treatment of cells with the pharmacological inhibitor, methyl-cyclo-dextran which destroys caveolae, activates Stat3 as well as Erk1/2, at all densities. Conversely, cav1 overexpression downregulates Stat3 and induces growth retardation or apoptosis in NIH3T3 fibroblasts and in breast cancer lines. In all cases, apoptosis was inhibited by co-expression of the constitutively active form of Stat3, Stat3C. Taken together, these findings point to cav1 as an inhibitor of Stat3 activity. In addition, it was previously demonstrated that cav1 upregulates p53, although the exact mechanism is unclear. Since Stat3 is known to inhibit p53 transcription through promotor binding, these data also point to the possibility that cav1 upregulation may, in fact, activate p53 through Stat3 inhibition. Our results further demonstrate for the first time that, in a feedback loop, Stat3 inhibition results in a dramatic increase in cav1 levels, indicating that Stat3 also downregulates cav1 expression. The above findings reveal the presence of a potent, negative regulatory loop between cav1, p53 and Stat3 that plays a crucial role in cellular survival.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1323. doi:10.1158/1538-7445.AM2011-1323
Abstract 1327: Analysis of metal content and distribution in profiling normal and tumor tissues from three human carcinomas
Authors: Farah Ibrahim O. , Nguyen Phoung X.
Published: June 2012

Studies have shown that elemental/metal homeostasis is very essential to the development of the cancer phenotype in many cancers including lung and liver carcinomas. The balance in the composition of trace elements/metals was recognized to be essential to normal homeostasis. Low Zn levels were implicated in the development of prostate as well as other cancers. The aim of this study was to investigate the differential relationship of metal concentrations and profiles in cancer and normal tissues of humans. It is hypothesized that essential elements/metal concentrations and profiles will show significant differences between cancer and normal tissues as well as between different tissue types in human tissue material. The study will establish critical element/metal profiles that provide correlations with the development of three major carcinomas. Normal human and tumor tissues of lung, breast and liver tissues used in this study were obtained from US Biomax Company. Tissue samples were prepared using standardized digestion procedure and the ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry) was used to determine the concentrations and profiles of 21 elements including Ag, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, Sb, Se, Sr, Tl, V, and Zn. Results showed that nine major elements of Al, Ba, Ca, Cr, Cu, Fe, Mg, Na, and Zn were found to be significantly different in term of their concentration profiles in normal and tumor tissues of human lung, breast and liver. It is concluded that metal/elemental homeostasis is essential for normal tissue function and that shifts in elemental distribution and content are tissue specific as well as carcinoma specific. These results are promising and warrant further studies to exploit the possibility of manipulating elemental content and distribution as a cancer therapeutic modality.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1327. doi:10.1158/1538-7445.AM2011-1327
Abstract 1330: p27 suppresses arsenite-induced Hsp27/Hsp70 expressions through inhibiting JNK2/c-Jun- and HSF-1-dependent pathways
Authors: Zhang Dongyun , Liu Jinyi , Yu Yonghui , Zuo Zhenghong , Guo Wei , Zhao Xuewei , Li Jingxia , Hu Yu , Yang Wancai , Shi Xianglin , Huang Chuanshu
Published: June 2012

p27 is an atypical tumor suppressor, which can regulate the activity of cyclin-dependent kinases (CDKs) and G0 to S phase transitions. More recent studies reveal that p27 may also exhibit its tumor suppressive function through regulating many other essential cellular events. However, the molecular mechanisms underlying these anti-cancer effects of p27 are largely unknown. In current studies, we found that depletion of p27 expression by either gene knockout or knockdown approaches resulted in upregulation of both Hsp27 and Hsp70 expressions at mRNA and promoter-derived transcription as well as protein levels upon arsenite exposure, indicating that p27 provided a negative signaling for regulating the expressions of Hsp27 and Hsp70. Consistently, arsenite-induced activation of JNK2/c-Jun and HSF-1 pathways was also markedly elevated in p27 knockout (p27-/-) and knockdown (shRNA p27) cells. Moreover, interfering the expression or function of JNK2, c-Jun and HSF-1, but not JNK1, led to dramatic inhibition of arsenite-induced Hsp27 and Hsp70 expressions. Collectively, our studies demonstrated that p27 suppressed Hsp27 and Hsp70 expressions at transcriptional level specifically through JNK2/c-Jun- and HSF-1-dependent pathways upon arsenite exposure, which provided additional important molecular mechanism for the tumor suppressive function of p27.

Key words: Arsenite, p27, Hsp27, and Hsp70

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1330. doi:10.1158/1538-7445.AM2011-1330
Abstract 1338: MicroRNAs in a mouse model of oral carcinogenesis
Authors: Tang Xiao-Han , Gudas Lorraine
Published: June 2012

MicroRNAs (miRNAs) can function as oncogenes or tumor suppressor genes. Aberrant expression of microRNAs has been reported in human tongue squamous carcinoma cells. In this study, we investigated the effects of the carcinogen, 4-nitroquinoline 1-oxide (4-NQO), on the expression of several miRNAs in mouse tongues by using a seminal mouse model of oral carcinogenesis that was established by our laboratory and demonstrates similarities to human oral tumors in terms of morphological, histopathological, and molecular characteristics. In addition, we studied the effects of the DNA methyltransferase (Dnmt) inhibitor 5-Aza-2′-deoxycytidine (5-Aza, 0.25 mg/kg body weight), all-trans retinoic acid (RA, given at 100 μg/kg body weight and 1 mg/kg body weight, respectively), and the combination of 5-Aza and the low dose RA on murine oral cavity carcinogenesis induced by 4-NQO and on mouse tongue miRNA expression levels in this mouse model. Compared with control mice (not treated with 4-NQO), 4-NQO treatment caused a remarked reduction in the expression of miR-26a and miR-124a in mouse tongues and an increase in CDK2 (one of miR-124a's targets) mRNA expression. Among all drug treatments, the combination of 5-Aza and the low dose RA attenuated the reduction in the expression of miR-124a caused by the 4-NQO treatment. To some extent, mice in all drug treatment groups showed a reduction in the degree of decrease in the expression of miR-26a in mouse tongues induced by 4-NQO. These results correlate with the data on neoplastic tongue lesion numbers and tongue lesion severity. Moreover, we found that RA, 5-Aza, and the combination of RA and 5-Aza all enhanced the expression of miR-26a and miR-124a in a human tongue squamous cell carcinoma cell line, SCC-15, and that the combination of RA and 5-Aza had the greatest effects. Collectively, our results show that miRNAs have potential as a strategy to reduce oral cavity cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1338. doi:10.1158/1538-7445.AM2011-1338
Abstract 134: The regulatory role of microRNA 338-3p in malignant gliomas
Authors: Hervey-Jumper Shawn , He Xiaobing , Zhu Thant , Gurrea Mikel , Talsma Caroline , Crowley Jessica , Costello Mark , Flack Callie , Jason Heth , Muraszko Karin , Fan Xing
Published: June 2012

Introduction: Glioblastoma multiforme (GBM) is the most common malignant brain tumor in adults. Even with optimal therapy, more than 70% of GBM patients will die within 2 years of diagnosis. MicroRNAs (miR) are important regulators of gene expression through posttranscriptional silencing of target mRNA. MicroRNA roles in cell proliferation, invasion, angiogenesis, and glioma stem cell activity are little known. In this study, we focus on the expression and function of microRNAs in human gliomas.

Methods: Using RNA extracted from 15 GBM patient samples and serum collected from 2 glioma patients, miR 338-3p expression, relative to normal brain and control serum, was examined using RT PCR. Regional miR expression within a single tumor was identified. A DNA fragment containing the hsa-miR-338-3p locus was amplified and cloned into a lentiviral vector, then transduced into GBM neurosphere lines. MicroRNA 338-3p and its downstream target, expression was assessed by RT PCR and western blot. GBM neurosphere growth was examined in vitro.

Results: Over-expression in miR 338-3p is associated with decreased glioma cell proliferation and neurosphere formation. MicroRNA 338-3p shows decreased expression in the core of malignant gliomas with increased expression at the tumors rim and migrating edge. MiR 338-3p expression induces cleaved caspase 3 expression. MiR 338-3p targets Histone deacetylase 4 (HDAC4).

Conclusion: MicroRNA 338-3p inhibits GBM neurosphere growth in vitro through reducing proliferation and inducing apoptosis possibly via targeting of HDAC4.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 134. doi:10.1158/1538-7445.AM2011-134
Abstract 135: MicroRNA repression of BIRC4/XIAP in lung cancer
Authors: Xie Yili , Camps Jordi , Awad Keytam S. , Wangsa Danny , Yang Jianhui , Yoo Nina , Ried Thomas , Kwong King F.
Published: June 2012

Background: MicroRNAs (miRNAs, miR) are short ∼22 nucleotide (nt) noncoding RNA molecules capable of regulating gene expression by targeting mRNA. Baculovirus IAP repeat containing protein-4 (BIRC4/XIAP) is the most potent member of the Inhibitor of apoptosis family of proteins (IAP) and an important cellular pro-survival stimulus. BIRC4 mRNA contains a long 3’ untranslated region (UTR) and its function remains unclear. Previously, we have shown that 17 candidate miRNAs can be identified that potentially interacted with BIRC4's 3’ UTR by using a computerized heuristic algorithm. An inverse relationship was discovered between miR-24 and BIRC4 in non-small cell lung cancers (NSCLC). The objective of this study is to determine whether miR-24 can directly target BIRC4 and consequently regulate apoptosis in NSCLC.

Methods: miRNA precursors and anti-miRNA inhibitors were transfected in NSCLC cells and their effect on BIRC4 protein expression was evaluated by western blot and their interaction with the BIRC4 3’UTR was detected by using luciferase reporter plasmids containing the BIRC4 3’UTR (wild type & mutant). Lentiviral p-Receiver-lv19-BIRC4 was transduced into A549 cells to generate stable clones overexpressing BIRC4 in order to examine miR-24's effects on a transcript devoid of the native 3’-UTR. The effects of miRNA on cell apoptosis signaling was determined by MTT cell viability assay, TdT apoptosis assay and Western blot for caspase-3 activation and PARP cleavage. Cytogenetic analyses (SKY &CGH) were performed to detect chromosomal abnormalities that may account for reduced expression of miRNA.

Results: miR-24 transfection down-regulates BIRC4 expression in NSCLC cells. Luciferase assay confirmed that miR-24 targets the BIRC4 3’ UTR at nucleotide positions 2294-2310. miR-24 also sensitizes intrinsically TRAIL-resistant A549 cells to TRAIL-induced cell apoptosis, which can be reversed by ectopic expression of miR-24-insensitive BIRC4. miR-24 sensitized-apoptosis is modulated via the canonical apoptosis pathway. Genomic deletion in the miR-24 coding region was found in NSCLC cells with corresponding low levels of miR-24. NSCLC or normal lung cells with normal/high levels of miR-24 did not exhibit cytogenetic deletion in the miR-24 coding region.

Conclusions: miR-24 down-regulates BIRC4 expression by directly targeting the BIRC4 3’UTR and can sensitize NSCLC cells to TRAIL-induced apoptosis. Genomic deletion contributes to the reduced expression of miR-24 in NSCLC. This finding raises the possibility that miR-24 mimetics may be of value in combination with TRAIL or other therapeutic strategies in the future treatment of lung cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 135. doi:10.1158/1538-7445.AM2011-135
Abstract 1371: Antitumor activity of a new quinoxalinyl-piperazine compound
Authors: Lee Young Bok , Chun Gina , Kim Deog J. , Ahn Chang H. , Kong Young D. , Jeon Moon K. , Kong Jae Y.
Published: June 2012

Novel 1-[(5 or 6-substituted alkoxyquinoxalinyl)aminocarbonyl]-4-(hetero)arylpiperazine derivatives were synthesized and evaluated as an anti-tumor agent. Despite their structural similarity to the quinoxalinyl-piperazine core scaffold, the IC50 values of the compounds against human cancer cells depends on the substitution at the quinoxaline ring but also from substituents at the phenyl ring. The best compound showing IC50 values ranging from 11 to 21 nμ was selected and characterized further both in vitro and in vivo. This compound was more potent against paclitaxel resistant HCT-15 colorectal cells compared to paclitaxel itself. Combined treatment of this compound with known anti-cancer drugs, such as paclitaxel, doxorubicin, cisplatin, gemcitabine or 5-fluorouracil, displayed synergistic growth inhibition of cancer cells. In mice bearing tumor xenografts, treatment with the compound completely inhibited the growth of various human tumors, enhanced tumor regression without effects on body weight compared to control animals. Mechanistic studies have shown that this quinoxalinyl-piperazine compound is a G2/M-specific cell cycle inhibitor and inhibits anti-apoptotic Bcl-2 protein with p21 induction. The results clearly demonstrate that our new quinoxalinyl-piperazine compound could become a novel class of anti-tumor chemotherapeutics.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1371. doi:10.1158/1538-7445.AM2011-1371
Abstract 1377: Identification and characterization of small molecule inhibitors of the activator protein-1 pathway
Authors: Miller Nicole R. , Huang Ruili , Xia Menghang
Published: June 2012

The activation of transcription factor activator protein-1 (AP-1) plays a critical role in multiple stages associated with carcinogenesis. The AP-1 complex is a dimeric transcription factor typically made up of proteins from JUN, FOS, ATF, and MAF families. Growth factors including EGF activate AP-1 via cell surface receptors such as EGF receptor (EGFR). EGFR activation of MAPK cascades lead to phosphorylation and nuclear translocation of AP-1 subunits. Discovery of selective inhibitors of the AP-1 pathway would lead to invaluable tools in the study, treatment and prevention of multiple cancers. To screen for AP-1 pathway inhibitors, a FRET-based AP-1 β-lactamase reporter was used to measure AP-1 activation in a ME-180 cervical cancer cell line. Approximately 75,000 compounds were screened, each at 7-15 concentrations, in a quantitative high-throughput screening (qHTS) format. Several novel structure series were identified from this screen. Hits selected based on a structure-activity relationship analysis were confirmed and further investigated for mechanism of action because EGF-stimulated AP-1 activation can be inhibited by multiple mechanisms in the pathway. Inhibitors mechanisms of action in the EFGR-mediated pathway were determined in follow-up studies including receptor inhibition, MAPK inhibition, and direct disruption of the AP-1 signaling complex. The identification and characterization of novel AP-1 inhibitors will lead to compounds that serve as probes of the AP-1 pathway and potential candidates for anticancer drug development.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1377. doi:10.1158/1538-7445.AM2011-1377
Abstract 1379: High throughput screening to identify molecules that alter VHL stability
Authors: Ding Zhiyong , Feng Zhehui , Fikes Nelda A. , Gao Meng , Si Wendy , Sobieski Mary M. , Stephan Clifford C. , Mills Gordon B. , Jonasch Eric
Published: June 2012

Von Hippel-Lindau (VHL) germ line and somatic mutations play determining roles in renal-cell carcinomas (RCC) as well as other diseases, including hemangioblastomas and pheochromocytomas. Although molecules upregulated as a consequence of VHL deficiency have been employed as drug targets in RCC cancer therapy, modulation of pVHL itself has not been explored as a therapeutic strategy in the treatment of VHL derived diseases.

Approximately one third of VHL mutations are point mutations, which destabilize pVHL and decrease pVHL intracellular levels, despite in some cases possessing residual functionality. Therefore, interventions that restabilize mutated pVHL may restore physiological protein levels and function.

We established a high-throughput screening system to identify small molecules that alter VHL stability. We fused an unstable W117A VHL mutant to a fluorescent protein Venus and transduced the VHL null 786-0 RCC cell line. The fluorescence and protein levels of W117A VHL-Venus were low in untreated cells, and increased significantly after treatment with the proteasome inhibitors MG132 or bortezomib. The fluorescence level served as a VHL protein stability readout for the screen. We then performed a screen on the Prestwick drug library and identified multiple candidates that stabilized VHL protein. Certain candidates have been shown to functionally regulate VHL stability as well as its downstream effecter HIF1a. Our work shows that the high-throughput screening system we established could efficiently identify small molecules that alter VHL stability and functionality, and facilitates exploring VHL as a drug target in the treatment of RCC as well as other VHL diseases.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1379. doi:10.1158/1538-7445.AM2011-1379
Abstract 1384: Estrogen receptor beta inhibits migration and invasion of breast cancer cells by regulating E-cadherin levels
Authors: Thomas Christoforos , Rajapaksa Gayani , Nikolos Fotis , Gustafsson Jan-Ake
Published: June 2012

Estrogen receptor beta (ERβ) mediates the effects of estrogens in a variety of human tissues including the mammary gland and regulates biological processes involved in initiation, progression and metastasis of breast cancer such as cell proliferation and migration. Although induction in cell-cell adhesion has been shown to be involved in the ERβ-mediated inhibition of cell migration, the molecular mechanism has not been fully elucidated. Here we show that induction in the expression of ERβ alters the morphology of the metastatic MDA-MB-231breast cancer cells by inducing cell-cell contact and inhibits migration and invasion. This correlates with an ERβ-mediated induction in the expression of the epithelial marker E-cadherin and downregulation of mesenchymal markers vimentin and N-cadherin. We found that the ERβ-mediated increase in the expression of E-cadherin involves an induction in the levels of miR-200 and a concomitant downregulation of its target component and transcriptional repressor of E-cadherin, ZEB1. These data suggest that ERβ through inhibiting migration and invasion in breast cancer cells may have a role in the clinical intervention of metastatic breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1384. doi:10.1158/1538-7445.AM2011-1384
Abstract 1387: WISP-1 increases MMP-2 expression and cell motility in human chondrosarcoma cells
Authors: Chiang Yi-Chun , Tang Chih-Hsin , Tan Tzu-Wei
Published: June 2012

Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. WISP-1 is a cysteine-rich protein that belongs to the CCN (Cyr61, CTGF, Nov) family of matricellular proteins. However, the effect of WISP-1 on migration activity in human chondrosarcoma cells is mostly unknown. Here we found that WISP-1 increased the migration and expression of matrix metalloproteinase (MMP)-2 in human chondrosarcoma cells (JJ012 cells). We also found that human chondrosarcoma tissues had significant expression of the WISP-1 which was higher than that in normal cartilage. α5β1 monoclonal antibody and MAPK kinase (MEK) inhibitors (PD98059 and U0126) inhibited the WISP-1-induced increase of the migration and MMP-2 up-regulation of chondrosarcoma cells. WISP-1 stimulation increased the phosphorylation of focal adhesion kinase (FAK), MEK and extracellular signal-regulated kinase (ERK). In addition, NF-κB inhibitors also suppressed the cell migration and MMP-2 expression enhanced by WISP-1. Moreover, WISP-1 increased NF-κB luciferase activity and binding of p65 to the NF-κB element on the MMP-2 promoter. Taken together, our results indicated that WISP-1 enhances the migration of chondrosarcoma cells by increasing MMP-2 expression through the α5β1 integrin receptor, FAK, MEK, ERK, p65 and NF-κB signal transduction pathway.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1387. doi:10.1158/1538-7445.AM2011-1387
Abstract 1388: Metastatic potential of B16 melanoma subclones indicated by cell stiffness measured by atomic force microscopy (AFM)
Authors: Suganuma Masami , Watanabe Tatsuro , Takahashi Atsushi , Fujiki Hirota
Published: June 2012

To investigate a new parameter for measuring the metastatic potential of cancer cells, we conducted nanomechanical analysis using atomic force microscopy (AFM). AFM, a probe microscope, has the advantage of measuring cell stiffness (elasticity) in physiological conditions without any pretreatment. Since cancer cells are softer than normal cells, the cell stiffness measured by AFM can be utilized as a new cancer diagnostic marker. Experimentally, we examined whether cell stiffness might reflect the metastatic potential of cancer cells using three subclones (B16-F10, B16-BL6, and B16-F1) of B16 melanoma cells. Migration potential was first determined by Transwell assay: B16-F10 and B16-BL6 cells showed 3- and 2- times more migrated cells into reverse sides of filter, at 5 μg/ml concentrations of fibronectin, than did B16-F1 cells. This indicates that B16-F10, B16-BL6, and B16-F1 cells have metastatic potential in the order of high, intermediate, and poor, respectively. AFM measurement clearly shows significant differences in cell stiffness of three B16 subclones, while the morphology and growth rate of these subclones are almost the same. Median values of Young’ modulus with B16-F10, B16-BL6, and B16-F1 cells were 395.12 Pa, 771.13 Pa, and 868.45 Pa, respectively. The results showed that highly metastatic B16-F10 cells are least stiff, suggesting that cell stiffness (Young's modulus) is directly associated with metastatic potential. Furthermore, we found that treatment with green tea catechin EGCG increased the cell stiffness of B16-F10 cells to greater than that of non-treated cells, and it also inhibited of cell migration in Transwell assay. Moreover, an inactive catechin, EC, did not have any effect on cell stiffness or cell migration. The results with EGCG strongly support our previous finding that EGCG in drinking water inhibits the metastasis of B16-F10 cells into the lungs of C57/BL6 mice. We have present for the first time evidence that the cell stiffness, as determined by AFM, is a useful biomarker for predicting metastatic potential and developing new preventive agents against metastasis. We discuss the significance of this mechanical and biochemical property (cell stiffness) in metastasis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1388. doi:10.1158/1538-7445.AM2011-1388
Abstract 1391: Simultaneous knockdown of MMP-9 and uPAR/cathepsin B retards α9β1 integrin-mediated cell migration via SSAT and potassium channel pathway in glioma xenografts
Authors: Veeravalli Krishna Kumar , Ponnala Shivani , Chetty Chandramu , Rao Jasti S.
Published: June 2012

The α9β1 integrin accelerates cell migration through the binding of α9 cytoplasmic domain to spermidine/spermine-N1-acetyltransferase (SSAT), which catalyzes the catabolism of higher order polyamines, spermidine and spermine, to the lower order polyamine, putrescine. Our recent studies have clearly demonstrated the role of α9β1 integrin in MMP-9, uPAR and cathepsin B-mediated cell migration in glioma xenograft cells (4910 and 5310). In the present study, we aimed to investigate the underlying mechanisms through which MMP-9 and uPAR/cathepsin B knockdown inhibits α9β1 integrin-mediated migration in glioma xenograft cells. Western blot, RT-PCR and immunofluorescence analyses revealed downregulation of SSAT levels both at the mRNA and protein levels by siRNA-mediated simultaneous knockdown of MMP-9 and uPAR/cathepsin B. In addition, we noted a prominent reduction in the expression of SSAT with MMP-9 and uPAR/cathepsin B knockdown in the tumor regions of 5310 injected nude mice brains. Co-localization of α9 integrin with kir4.2, an inward rectifier potassium channel, was observed in both 4910 and 5310 xenograft cells. However, MMP-9 and uPAR/cathepsin B knockdown in these cells prominently reduced the co-localization of α9 with kir4.2. Interestingly, MMP-9, uPAR and cathepsin B overexpression in these xenograft cells significantly elevated SSAT mRNA and protein levels. Further, the migratory potential of MMP-9/uPAR/cathepsin B overexpressed 4910 and 5310 cells was not affected by either glybenclamide or tertiapin-Q but instead was significantly inhibited by either barium or kir4.2 siRNA treatments. Taken together, our results from the present and earlier studies clearly demonstrate that α9β1 integrin-mediated cell migration utilizes SSAT and kir4.2 potassium channel pathway, and inhibition of the migratory potential of these glioma xenograft cells by simultaneous knockdown of MMP-9 and uPAR/cathepsin B could be attributed to the reduced SSAT levels and co-localization of α9 integrin with kir4.2 potassium channels. Based on these findings, we conclude that the simultaneous knockdown of MMP-9 and uPAR/cathepsin B retards SSAT and potassium channel pathway-mediated cell migration through the α9β1 integrin.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1391. doi:10.1158/1538-7445.AM2011-1391
Abstract 1393: CD44 has dual functions to enhance the hyaluronan-induced chemokinesis in cancer cells as an associated molecule of hyaluronidase2-mediated HA catabolism and a hyaluronan receptor for RhoGTPase activation
Authors: Harigaya Kenichi , Saito Teruyoshi , Azuma Kazuhiko , Umemiya Toshifumi , Toyoda Akihiro , Shida Yuki , Kitagawa Motoo
Published: June 2012

Major oncogenic signaling pathways are involved in the alteration of hyaluronan (HA) metabolism of cancer cells, such as Erb B, Wnt, TGF-β and p53 signalings. HA is a widely distributed extracellular matrix glycosaminoglycan and changes biological activities depending on its molecular sizes. Our recent study has shown that fragmented low molecular weight (LMW) HA (approximately 20 kDa) is an autocrine chemokinetic motility factor supported by the HA synthethase2-hyaluronidase2 / CD44 system on the plasma membrane of the cancer cells. In HeLaS3 cells, LMW-HA stimulation effectively enhanced cell spreading and random cell movement (chemokinesis) among different molecular sizes of HA (3, 23, 230, 940-kDa). Biochemically, LMW HA effectively provoked a RhoA activation, recurrent Cdc42 and Rac1 activation, and sustained phosphorylation of ERK1/2. Constrastly, 220 kDa HA did not enhance chemokinesis of HeLaS3 cells with similar activation profiles of Rac1 and ERK 1/2 except for the progressive decrease of Cdc42 and RhoA activation. The transfection of CD44 si-RNA to HeLaS3 cells abolished the enhanced chemokinesis with the remarkable decrease of Rho GTPase activation even in LMW HA stimulation. Accordingly, our study showed that CD44 has dual functions to enhance the HA-induced chemokinesis in cancer cells as an associated molecule of hyaluronidase2-mediated HA catabolism and a HA receptor for RhoGTPase activation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1393. doi:10.1158/1538-7445.AM2011-1393
Abstract 1395: CD16+ dendritic cells (DC) promote squamous carcinoma cell (SCC) survival, and SCC affect DC phenotype and migration
Authors: Kurago Zoya B. , Ramanathapuram Lalitha
Published: June 2012

In the inflammatory mucosal microenvironment of head and neck squamous cell carcinoma (HNSCC), dendritic cells (DC) are prominent; they express CD16, and are usually in direct contact with tumor cells. Mucosal and inflammation-associated DC develop from monocytes, and monocyte-derived DC are used in HNSCC immunotherapy. However, beyond apoptotic tumor cell uptake and presentation of tumor antigens by DC, HNSCC cell interactions with DC are poorly understood. Using co-cultures of monocyte-derived DC and established HNSCC cell lines we found that carcinoma cells induced significant increases in CD16 expression on DC while promoting a CD1a+CD86dim immature phenotype, similar to that observed in HNSCC specimens. Moreover, HNSCC cells strongly affected DC migration, both steady-state and CCL21-induced. The effects of carcinoma cells on migration were donor-dependent, and CCL21-induced migration directly correlated with HNSCC-mediated effects on CCR7 and CD38 expression on DC. Most remarkably, the numbers of live detached HNSCC cells were orders of magnitude higher in DC-HNSCC co-cultures than in parallel HNSCC cell cultures without DC. This study provides a novel insight into the outcomes of DC-HNSCC interactions relevant to the tumor microenvironment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1395. doi:10.1158/1538-7445.AM2011-1395