bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract B18: Induction of tumor cell apoptosis by a proteasome deubiquitinase inhibitor is associated with oxidative stress and activation of JNK/AP1 mediated signaling.
Authors: D'Arcy Padraig , Brnjic Slavica , Mazurkiewicz Magdalena , Linder Stig
Published: August 2014

Tumor cells are dependent on a functioning ubiquitin-proteasome system (UPS), making it an ideal target for the development of anti-cancer therapies. The approval of bortezomib has verified this, however several problems have emerged including dose-limiting toxicity and tumor relapse. Thus there is an urgent need not only to identify new drugs but also new drug targets for the improved treatment of cancer patients. We recently identified the small molecule b-AP15 as an inhibitor of proteasome de-ubiquitinase (DUB) activity. b-AP15 inhibits the activity of two proteasome-associated DUBs, UCHL5 and USP14, resulting in defective poly-ubiquitin processing, proteasome shutdown, apoptosis and cell death in vitro and in vivo cancer models. Investigations into the mechanism of action showed that b-AP15 induced apoptosis via the induction of oxidative stress and activation of JNK/AP1 mediated stress signaling. Inhibition of the UPS with bortezomib or b-AP15 induced a similar stress response, characterized by ER stress, activation of the JNK/AP1 pathway and production of reactive oxygen species (ROS). Importantly pharmacological inhibition of JNK or treatment with ROS scavengers inhibited b-AP15-induced apoptosis without altering UPS inhibition. Our data suggests a role for ROS production and JNK signaling in proteasome DUB inhibitor induced apoptosis.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B18.

Citation Format: Padraig D'Arcy, Slavica Brnjic, Magdalena Mazurkiewicz, Stig Linder. Induction of tumor cell apoptosis by a proteasome deubiquitinase inhibitor is associated with oxidative stress and activation of JNK/AP1 mediated signaling. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B18.
Abstract B181: TP53 mutation screening in patients with recurrent platinum-sensitive ovarian cancer.
Authors: Brana Irene , Moore Kathleen , Welch Stephen , Shapira-Frommer Ronnie , Gibbon Darlene , Hirte Hal , Rivkin Saul , Coleman Robert , Prendergast Gerry , Moxley Katherine M. , Jou Ying-Ming , Marinucci Michelle , Freshwater Tomoko , McCarthy Sharon , Anthony Mark Lee , Rose Shelonitda , Oza Amit M.
Published: August 2014

Background: TP53 is commonly mutated in ovarian cancer. As potential agents targeting TP53 mutant or wt are under development, the efficiency and accuracy for determination of TP53 mutations in a clinical trial was evaluated.

Methods: Eligible patients, including relapsed, platinum-sensitive ovarian, fallopian tube, or primary peritoneal cancer, underwent pre-screening for a clinical trial with MK1775, eligibility for which was determined by the presence of functional TP53 mutations (Brana I et al, ASCO 2013). Single base substitution and single base deletion mutations in exons 2 - 11 and the flanking splice junction in the TP53 gene were analyzed using AmpliChip p53 Assay (Roche Molecular Diagnostics, California) on archival tumor specimens.

Results: Seventy-five women were screened for eligibility based on TP53; 43 had TP53 mutations, 27 were TP53 wild-type (wt), and 5 undetermined (Table 1). No clustering of mutations to define hot spots was evident. The most commonly mutated region was exon 5 (11 mutations). Missense mutations were the most common mutation type (69.7%); although, nonsense (14 %), splice (14 %), and frame shift mutations (2.3%) were also observed (Table 1). Most of the missense mutations were in exons 5 to 8 (90%). The mean turnaround time from sample reception to final TP53 status report was 3 days (range 1:14).

Conclusions: The TP53 mutational status has been successfully determined in 93.3% of patients with a short turnaround time, supporting the feasibility of TP53 determination in the clinical setting. In our patient population, 57.3% had a TP53 mutation. Potential geographic differences in the incidence TP53 mutations cannot be evaluated due to the limited sample size; this hypothesis should be further evaluated in a larger patient population

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B181.

Citation Format: Irene Brana, Kathleen Moore, Stephen Welch, Ronnie Shapira-Frommer, Darlene Gibbon, Hal Hirte, Saul Rivkin, Robert Coleman, Gerry Prendergast, Katherine M. Moxley, Ying-Ming Jou, Michelle Marinucci, Tomoko Freshwater, Sharon McCarthy, Mark Lee Anthony, Shelonitda Rose, Amit M. Oza. TP53 mutation screening in patients with recurrent platinum-sensitive ovarian cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B181.
Abstract B184: In vitro and in vivo profiling of novel mTORC1/2 inhibitor DS-3078a.
Authors: Wakita Kenichi , Kiga Masaki , Togashi Noriko
Published: August 2014

DS[[Unable to Display Character: ‑]]3078a is a potent, selective small molecule inhibitor of the catalytic site of the mammalian target of rapamycin (mTOR). Our previous study showed DS-3078a to inhibit mTOR kinase activity in a concentration-dependent manner with an IC50 (concentration resulting in 50% of maximum inhibition) of approximately single digit nano molar. Here the antitumor potency of DS-3078a against various cancer cell lines in vitro and in vivo is shown. DS-3078a was applied to a 230 cell line panel assay to evaluate cell growth inhibition and apoptosis induction activity. In this study, DS-3078a was found to be a highly cytostatic compound with strong cell growth inhibiting activity. DS-3078a exhibited GI50s lower than 500 nM against over 200 cell lines and a 5-fold and higher caspase activation against only 36 cell lines. Among 12 in vivo xenograft models, 9 of 12 xenograft models demonstrated greater than a 50% tumor growth inhibition response at half of MTD dosing. There are several well-known selective mTOR kinase inhibitors including AZD8055 and OSI-027. When comparing the cellular response among these compounds, DS-3078a was found to have a weaker induction of the sub G1 population against AN3 CA human endometrial carcinoma cell line than the other two compounds, despite its similar kinase inhibiting profile against them. In a previous study, an increase of the phospho Akt(T308) by DS-3078a treatment in A498 human renal cell carcinoma, which was a sign of negative feedback loop disruption by inhibition of mTORC1 was demonstrated. In this model, AZD8055 and OSI-027 did not increase phospho Akt(T308), which implies inhibition of the PI-3K signal at higher concentrations. To understand the impact of the cytostatic characteristics of DS-3078a, in vivo mTOR signal inhibition at MTD using tumor bearing mouse was measured and compared to the signal inhibition pattern of AZD8055 and the PI-3K/mTOR dual inhibitor DS-7423. DS-3078a fully inhibited mTORC1 and mTORC2 downstream signals for 24 hr, while signal inhibition by DS-7423 was reduced by 18 hr. AZD8055 showed a similar pattern to DS-7423 at MTD dosing. This study highlights the unique characteristics of DS-3078a which may offer a unique differentiation of response and toxic profile compared to other mTOR inhibiting compounds in the clinical setting.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B184.

Citation Format: Kenichi Wakita, Masaki Kiga, Noriko Togashi. In vitro and in vivo profiling of novel mTORC1/2 inhibitor DS-3078a. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B184.
Abstract B195: MAGI3-Akt3, a novel fusion protein in the PI3K pathway in cancer.
Authors: Brown Kristin , Toker Alex
Published: August 2014

Aberrant activation of the PI3K/Akt pathway is found in approximately 70% of breast cancers. We recently identified a recurrent rearrangement that produces an in-frame fusion protein containing Akt3 and the scaffolding protein MAGI3. MAGI3-Akt3 is the first fusion protein that has been identified in the PI3K pathway. We propose that MAGI3-Akt3 is a novel oncogene in breast cancer and that the oncogenic activity of the fusion protein results from disruption of the PI3K/Akt pathway. Within the fusion, Akt3 has a disrupted PH domain prior to glutamate 17 (E17). As a result the fusion protein is constitutively phosphorylated in the Akt3 kinase domain and expression of MAGI3-Akt3 in breast cancer cells enhances Akt substrate phosphorylation. Constitutive MAGI3-Akt3 kinase activity can be inhibited by ATP-competitive small molecule Akt inhibitors but is resistant to the allosteric Akt inhibitor MK2206 which is currently in phase II clinical trials. Our results indicate that ATP competitive Akt inhibitors should be evaluated in clinical trials for the treatment of fusion-positive breast cancers. The fusion protein also contains a severely truncated portion of the scaffolding protein MAGI3. In particular, the fusion lacks the second PDZ domain of MAGI3 that has been reported to bind to PTEN and be required for the inhibitory effect of PTEN on PI3K pathway activity. We have demonstrated that disruption of MAGI3 in breast cancer cell lines does indeed promote PI3K pathway hyperactivity in a PTEN-dependent manner. In addition, the fusion lacks the fifth PDZ domain of MAGI3 and our studies indicate that this disrupts the interaction of MAGI3 with PHLPP2, a phosphatase that directly dephosphorylates Akt at pS473. Our studies therefore demonstrate that the MAGI3-Akt3 translocation significantly perturbs PI3K pathway activity via activation of an oncogene (Akt3) and dysregulation of two tumor suppressors (PTEN and PHLPP2). We are currently continuing studies to elucidate the oncogenic mechanism(s) of MAGI3-Akt3 in breast cancer.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B195.

Citation Format: Kristin Brown, Alex Toker. MAGI3-Akt3, a novel fusion protein in the PI3K pathway in cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B195.
Abstract B196: FGFR3 as a potential target for gastric cancer.
Authors: Lee Choong-kun , Lee Won Suk , Kim Jeong Min , Lee Myung Eun , Park Kyu Hyun , Kim Tae Soo , Kim Hyo Song , Jeung Hei-Cheul , Chung Hyun Cheol , Rha Sun Young
Published: August 2014

While trastuzumab against HER-2 over-expression is the only approved targeted therapy against gastric cancer, it is important to find the biologically significant genetic aberrations in most of gastric cancer without HER-2 overexpression. We performed phospho-RTK (receptor tyrosine kinase) array in 25 gastric cancer cell lines, and confirmed fibroblast growth factor receptor 2 and 3 (FGFR2, 3) as one of the highly phosphorylated RTKs. Knockdown of FGFR3 with transfecting small interfering RNA (siRNA) induced the decrement of phospho-FGFR (653/654) in a time-dependent manner in cell lines with highly activated FGFR3, Hs746T and SNU-5. While cell cycle analysis and apoptosis assay showed no significant changes, invasiveness and anchorage-independent growth was inhibited after FGFR3 siRNA transfection. Modulation of downstream signaling molecules was observed by western blot after transfecting FGFR3 siRNA in Hs746T and SNU-5 cell lines in comparing with FGFR2 activated cell lines (KATO III, SNU-16) transfected with FGFR2 siRNA, since previous reports showed that FGFR2 amplification is important in gastric cancer in influencing cell proliferation and survival. Phospho-AKT was down-regulated in both FGFR2 and FGFR3 activated cell lines after specific siRNA transfection, implying that gastric cancer cells with FGFR2 or FGFR3 activation might be both dependent on PI3K-AKT-mTOR pathway. When we treated mice bearing subcutaneous SNU-5 tumor xenografts with oral FGFR inhibitor TKI-258 (70mg/kg daily), TKI-258 treated group showed anti-tumor growth and anti-angiogenic effect compared with control group. Immunohistochemistry (IHC) against FGFR3 among 116 N3 gastric cancer patient tissues showed 3+ in 62.9%, while FGFR2 positivity was only 11.2%. In summary, we identified FGFR3 harbors significant biological role in subset of gastric cancer patients as FGFR2. Further studies for validating the efficacy of FGFR inhibition in preselected subset of patients would support the proper development of FGFR inhibitor in gastric cancer.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B196.

Citation Format: Choong-kun Lee, Won Suk Lee, Jeong Min Kim, Myung Eun Lee, Kyu Hyun Park, Tae Soo Kim, Hyo Song Kim, Hei-Cheul Jeung, Hyun Cheol Chung, Sun Young Rha. FGFR3 as a potential target for gastric cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B196.
Abstract B197: Proteomic based analysis of ovarian cancer pathways.
Authors: Rikova Klarisa , Hall Benjamin , Levy Tyler , Possemato Anthony , Wang Yi , Lee Kimberly , MacNeil Joan , Guo Ailan , Mulhern Daniel , Keroack Caroline , Ren Jian M. , Beausoleil Sean A. , Lonning Scott , Comb Michael J.
Published: August 2014

Recent genomic-based studies have suggested ovarian cancer is a disease of copy instability, with 63 regions of focal amplification, rather than a disease driven by mutation. However, this analysis has been unable to identify changes in protein expression, modification, and activity. In this study we developed a highly quantitative MS/MS approach to examine the ratio of protein levels, combining TMT labeling with a number of motif and site-specific antibodies to identify deregulated signaling pathways between tumor and normal specimens. We identified over 1400 uniquely upregulated proteins, and over 1600 upregulated post-translational modification sites across 79 tumors and 19 normal tissue samples. We were able to survey activity of over 400 kinases and over 100 other enzymes as well as the substrates associated with them. Our study was able to map these upregulated proteins based on abundance and activity level to their regions of focal amplifications. By focusing on activated cell circuitry, the approach outlined here provides insight into cancer biology not available at the chromosomal and transcriptional levels. This approach may reveal new connections among pathways and candidates for therapeutics and diagnostics.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B197.

Citation Format: Klarisa Rikova, Benjamin Hall, Tyler Levy, Anthony Possemato, Yi Wang, Kimberly Lee, Joan MacNeil, Ailan Guo, Daniel Mulhern, Caroline Keroack, Jian M. Ren, Sean A. Beausoleil, Scott Lonning, Michael J. Comb. Proteomic based analysis of ovarian cancer pathways. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B197.
Abstract B199: Transcriptional regulation of KLF4 by Yin Yang 1 (YY1) in pediatric B-NHL and clinical significance.
Authors: Vega Mario I. , Valencia-Hipolito Alberto , Hernández-Atenógenes Miriam , Vega Gabriel G. , Mayani Hector , Huerta-Yepez Sara , Bonavida Benjamin
Published: August 2014

Krüppel-like factor 4 (KLF4) is a member of the KLF zinc-finger containing transcription factor family. Supporting evidence has established that KLF4 is either an oncogene or a tumor suppressor. Reported studies have indicated the involvement of KLF4 in the regulation of apoptosis, proliferation, and differentiation of B cells and B-cell malignancies. In contrast to adult lymphomas and solid tumors, recently, we have shown in a TMA the overexpression of KLF4 in pediatric NHL tumor tissues. The KLF4 overexpresion predicted unresponsiveness to CHOP treatment. In addition, we have also reported that the transcription factor Yin Yang 1 (YY1) is overexpressed in B-NHL and is a prognostic factor. We hypothesized that the coexpression of KLF4 and YY1 may result from the transcriptional regulation of KLF4 by YY1. This hypothesis was tested in various experimental designs both in cell lines and tumor tissues derived from patients. Analysis of the B-NHL cell line Ramos revealed that both KLF4 and YY1 are overexpressed compared to normal B cells. The transfection of Ramos with siRNA YY1 showed significant inhibition of KLF4. In silico analyses of the KLF4 promoter identified the presence of four putative binding sites for YY1. We confirmed that the -126 site as the binding site for YY1 by CHIP analysis. We also used a reporter system of the KLF4 promoter and mutated the putative binding site for YY1 (-126) and confirmed it as an important site for the regulation of KLF4. The coexpressions of KLF4 and YY1 were examined in TMA of pediatric lymphomas and showed by IHC that all of the tumor tissues exhibited a positive correlation between the expression of KLF4 and YY1 and the correlation was markedly significant in the Burkitt subtype. KLF4 acts as a transcriptional activator of epithelial genes and as a repressor of mesenchymal genes. In addition, KLF4 suppresses the extrinsic apoptotic pathway by inhibiting the activation and cleavage of caspases (7, 9, and 3). Thus, the overexpression of KLF4 in lymphoma may be responsible, in part, in the pathogenesis, malignancy, and drug resistance. The present findings suggest that both KLF4 and YY1 are prognostic biomarkers in pediatric lymphoma. Further, inhibitors of KLF4 are being clinically tested and may be applicable in the treatment of lymphoma.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B199.

Citation Format: Mario I. Vega, Alberto Valencia-Hipolito, Miriam Hernández-Atenógenes, Gabriel G. Vega, Hector Mayani, Sara Huerta-Yepez, Benjamin Bonavida. Transcriptional regulation of KLF4 by Yin Yang 1 (YY1) in pediatric B-NHL and clinical significance. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B199.
Abstract B202: Hand-foot syndrome, the main side effect of patients with metastatic renal cell carcinoma treated with sunitinib.
Authors: Bensalem Assia , Bouzid Kamel
Published: August 2014

Background: Hand-foot syndrome (HFS) and related skin toxicities are common side effects of tyrosine kinase inhibitors such as sunitinib (SU), a multitargeted inhibitor of VEGF and PDGF receptors plus other receptor tyrosine kinases. In the treatment of naïve metastatic renal cancer carcinoma (mRCC) patients (pts), sunitinib showed superior progression-free survival (PFS) and objective response rate (ORR) over interferon-alfa, with a median PFS of 11 mo and median overall survival (OS) of 26.4 mo, establishing SU as a reference standard of care (Motzer et al, 2009). In this analysis, correlations between SU-associated HFS and efficacy endpoints were investigated in mRCC pts from January 2009 to January 2011 in the first- and second-line treatment settings. Methods: A total of 23 patients who received single-agent SU as 50 mg/d on a 4-week-on/2-week-off schedule (n=17; 73.9%) or 37.5 mg (n=6; 26%). Median PFS and OS were estimated and compared between pts with vs without HFS. Adverse events were recorded regularly. Results: Of 23 pts, 9 (39%) developed any-grade HFS, compared with 14 (60.8%) who did not. Most HFS (58%) initially occurred during the first 3 treatment cycles. Pts who developed HFS had significantly better ORR (55% vs. 32%), PFS (12 vs. 8 mo), and OS (23 vs. 11 mo) than pts who did not develop HFS.Conclusions: In mRCC pts, SU-associated HFS was significantly and independently associated with improved clinical outcomes. Overall, pts who did not develop HFS still had substantial benefit from SU. However, the presence of HFS identified a subset of pts that manifested highly favorable efficacy results with SU. This is suggesting that development of HFS may serve as a predictive biomarker of SU efficacy.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B202.

Citation Format: Assia Bensalem, Kamel Bouzid. Hand-foot syndrome, the main side effect of patients with metastatic renal cell carcinoma treated with sunitinib. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B202.
Abstract B212: Integrating the pre-clinical pharmacokinetic, pharmacodynamics, and efficacy data for AZD9291, an oral, irreversible inhibitor of EGFR activating (EGFRm+) and resistant (EGFRm+/T790M) mutations and an active metabolite to predict the human pharmacokinetics and potential efficacious dose in patients.
Authors: Ballard Peter , Ashton Susan , Cross Darren , Dimelow Richard , Yates James
Published: August 2014

Small molecule tyrosine kinase inhibitors gefitinib and erlotinib have demonstrated clinical benefit in advanced NSCLC patients with the EGFR activating mutation but ultimately disease progression develops due to resistant mutations. The most common resistant mutation is EGFR T790M and remains a key area of unmet need.

AZD9291 is an irreversible inhibitor of both the EGFR activating mutant (EGFRm+) and resistance mutation (EGFRm+/T790M), while maintaining a margin to wild type EGFR. AZD9291 has demonstrated impressive efficacy and regressions at low doses in mouse xenograft models for both activating (EGFRm+) and resistant (EGFRm+/T790M) mutant forms of EGFR (PC9 and H1975 cell lines). Analysis of plasma samples from these xenograft studies identified a des-methylated metabolite circulating in addition to AZD9291 with subsequent in vitro studies indicating the metabolite was around five fold more potent than AZD9291.

A program of mouse xenograft studies was undertaken to determine the tumor pEGFR pharmacodynamics (PD) and tumor growth inhibition (TGI) of AZD9291 and metabolite. Mathematical models incorporating an irreversible binding component have been developed to describe the contribution of AZD9291 and metabolite exposure to the pEGFR PD and TGI in the mouse (a PK/PD-TGI model). Pre-clinical drug metabolism and pharmacokinetic data were used to predict the human pharmacokinetics of AZD9291 and formation of the active metabolite. The predicted human exposures of both AZD9291 and metabolite were then used to drive the PK/PD-TGI model to simulate inhibition of pEGFR and inhibition of tumor growth. Assuming that human tumours and biomarkers behave in a similar way to those in mouse xenografts, these simulations suggest that a dose of 7-17 mg of AZD9291 once a day would be efficacious in patients with advanced NSCLC harboring the EGFR activating and T790M resistant mutations.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B212.

Citation Format: Peter Ballard, Susan Ashton, Darren Cross, Richard Dimelow, James Yates. Integrating the pre-clinical pharmacokinetic, pharmacodynamics, and efficacy data for AZD9291, an oral, irreversible inhibitor of EGFR activating (EGFRm+) and resistant (EGFRm+/T790M) mutations and an active metabolite to predict the human pharmacokinetics and potential efficacious dose in patients. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B212.
Abstract B224: HPV-stratified analysis of prognostic role of miR-21 in oropharyngeal squamous cell carcinoma.
Authors: Ko Yoon Ho , An Ho Jung , Sun Der Sheng , Won Hye Sung , Kang Jin Hyoung , Jung Chan-Kwon
Published: August 2014

Background: Both smoking and human papillomavirus (HPV) infection play an significant role in the development and progression of oropharyngeal squamous cell carcinoma (OSCC). MicroRNAs are short noncoding RNAs that regulate multiple mRNAs and are frequently dysregulated in cancer. The miR-21 microRNA is overexpressed in a wide variety of cancers and has been causally related to cellular proliferation and apoptosis. In this study, we investigated the association between the expression of miR-21 and the clinicopathologic features by stratified analysis based on HPV infection status.

Patients and Methods: The expression of miR-21 in the OSCC tissues of 137 patients was evaluated by in situ hybridization method. In addition, PDCD4 and PTEN were also examined by immunohistochemistry using tissue microarray. The clinicopathological implications of these molecules were analyzed statistically.

Results: The up-regulation of miR-21 expression was 22.7% for HPV negative group and 42.1% for HPV positive group (P = 0.081), and significantly correlated with advanced lymph node metastasis and extracapsular extension (P = 0.005 and P = 0.014, respectively). There was a significant association between miR-21 and cytoplasmic PDCD4 overexpression (P = 0.027). Kaplan-Meier analysis showed that up-regulation of miR-21 was significantly related with shorter overall survival (OS; 77.0 v 193.0 months; P =0.05) in HPV-negative OSCC, but not in HPV-positive OSCC (P =0.95). At HPV-stratified multivariate analysis, up-regulation of miR-21 was independent prognostic factor for both relapse-free survival (RFS; HR, 2.681; 95% CI, 1.090 to 6.591; P = 0.032) and OS (HR, 6.286; 95% CI, 2.047 to 19.302; P = 0.001).

Conclusion: Up-regulation of miR-21 expression is closely associated with poor prognosis in HPV-negative OSCC, but not in HPV-positive OSCC, suggesting that miR-21 may have a different role according to the HPV infection status.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B224.

Citation Format: Yoon Ho Ko, Ho Jung An, Der Sheng Sun, Hye Sung Won, Jin Hyoung Kang, Chan-Kwon Jung. HPV-stratified analysis of prognostic role of miR-21 in oropharyngeal squamous cell carcinoma. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B224.
Abstract B230: Targeting mitochondria for metastatic lung adenocarcinoma specific lethality.
Authors: Gruener Barbara M. , Chuang Chen-Hua , Linde Ian , Chiou Shin-Heng , Readhead Ben , Dudley Joel , Doench John , Root David , Winslow Monte M.
Published: August 2014

Introduction: Lung cancer is the leading cause of cancer deaths in the United States. Its ability to leave the primary tumor and establish inoperable metastasis impairs successful therapy and is a major contributor to its lethality. A genetically engineered mouse model recapitulates the human disease very well, incorporating conditional alleles of the Kras oncogene and p53 tumor suppressor. Recently, cell lines generated from non-metastatic primary lung tumors (TnonMet) and metastases (Met) in this model were shown to maintain their metastatic state and exhibit dramatic differences in gene expression programs. This unique set of cell lines from early stage non-metastatic tumors and late-stage metastases provides an opportunity to understand whether cancer progression also creates unique vulnerabilities.

Experimental design: A pooled lentiviral-shRNA library screen which targeted ∼20,000 genes with >92,000 shRNA in two TnonMet and two Met cell lines was used to systematically uncover genes that are specifically required to sustain metastasis survival or growth. High-throughput sequencing of the shRNA in the cancer cell populations before and after 20 population doublings in culture identified shRNAs that disadvantaged each cell line. Gene-set enrichment algorithm was utilized to analyse the data. qRT-PCR, cell competition assays and mitochondria-specific dyes were used to verify the results and unravel the underlying mechanism.

Results and Conclusion: The analysis of our pooled shRNA screen revealed mitochondrial ribosomal protein (Mrp) complexes as the top two gene-sets; in fact individual shRNA targeting more than 15 Mrp genes selectively disadvantaging Met cells with minimal impact on TnonMet cells. These results were individually verified with qRT-PCR. Interestingly, Met cells showed increased expression of mitochondria encoded genes, pointing to a strong imbalance in mitochondrial homeostasis. Furthermore, mitochondria-targeted therapy blocking mitochondrial translation or replication significantly inhibited Met cell growth more than TnonMet cell growth. Taken together, these results point to mitochondria as a metastasis-specific therapeutic target in lung adenocarcinoma and need to be further investigated.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B230.

Citation Format: Barbara M. Gruener, Chen-Hua Chuang, Ian Linde, Shin-Heng Chiou, Ben Readhead, Joel Dudley, John Doench, David Root, Monte M. Winslow. Targeting mitochondria for metastatic lung adenocarcinoma specific lethality. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B230.
Abstract B232: PIM1 kinase is essential for the growth of MYC-overexpressing triple-negative breast tumors and is an efficacious therapeutic target.
Authors: Horiuchi Dai , Zhou Alicia Y. , Corella Alexandra N. , Yau Christina , Lawson Devon A. , Bazarov Alexey V. , Yaswen Paul , McManus Michael T. , Welm Alana L. , Werb Zena , Goga Andrei
Published: August 2014

While de-regulated MYC signaling has been identified in a wide variety of human malignancies, no targeted therapeutic strategies have been established to target tumors with elevated MYC expression. We have previously reported that receptor “triple negative” (TN) breast cancers, which lack predictive biomarkers of response (i.e., estrogen/progesterone receptors, human epidermal growth factor receptor 2), exhibit significantly elevated MYC expression as well as MYC pathway activation (Horiuchi, D., et al. 2012 JEM). In an effort to uncover the potential Achilles’ heels of TN tumors, we performed a kinome, synthetic-lethal shRNA screen in human mammary epithelial cells in which MYC activity can be controlled (i.e., HMEC-MycER cells). The screen yielded 13 potential synthetic lethal partners of MYC, including recently described AMPK-related kinase 5 (Liu, L., et al. 2012. Nature). One of our top hits is the proto-oncogene PIM1, previously shown by others to be a genetic enhancer of MYC in transgenic mouse models of lymphomas and prostate cancer. Our bioinformatics studies performed on four independent clinical cohorts (n: 146 ∼ 683 patients each) show that in all the cohorts both MYC and PIM1 are significantly enriched in the TN populations. MYC and PIM1 expression are correlated in three out of the four cohorts. Furthermore, we find that PIM1 overexpression is a poor prognostic factor associated with diminished recurrence-free survival. Our in vivo efficacy studies using conventional as well as novel “human-in-mouse” orthotopic xenograft models demonstrate that PIM1 is required for the growth of MYC-overexpressing human TN tumors. We are currently investigating the cellular mechanisms by which PIM kinase inhibition causes such growth defects.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B232.

Citation Format: Dai Horiuchi, Alicia Y. Zhou, Alexandra N. Corella, Christina Yau, Devon A. Lawson, Alexey V. Bazarov, Paul Yaswen, Michael T. McManus, Alana L. Welm, Zena Werb, Andrei Goga. PIM1 kinase is essential for the growth of MYC-overexpressing triple-negative breast tumors and is an efficacious therapeutic target. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B232.
Abstract B235: The role of eIF4E in promoting melanoma cell proliferation and maintaining acquired resistance to vemurafenib in melanoma.
Authors: Zhan Yao , Dahabieh Michael S. , del Rincon Sonia V. , Miller Wilson H.
Published: August 2014

In eukaryotic cells, mRNA translation is restricted by the translation initiation step, in which eIF4E has been regarded as a master regulator. Overexpression of eIF4E has been found in different cancer types; however, whether eIF4E is involved in melanoma tumorigenesis and resistance to standard of care in melanoma remains unclear. We hypothesize that eIF4E promotes melanoma cell proliferation and facilitates the development of acquired resistance to the B-raf inhibitor, Vemurafenib. From our preliminary data, we show that by genetically knocking down eIF4E via siRNA or by using a pharmacological inhibitor of eIF4E, 4EGI-1, we can significantly repress the proliferation of a subset of melanoma cell lines. In addition, eIF4E activity contributes to the proliferation of some melanoma cell lines with acquired resistance to Vemurafenib, since siRNA-silencing eIF4E decreases their proliferation. Similarly, 4EGI-1 seems to be more effective at inhibiting cell proliferation of Vemurafenib resistant lines compared to their parental controls. Finally, we found that autophagy may act as a pro-survival mechanism in melanoma cell lines, based on the observation that the autophagy inhibitors Chloroquine, Bafilomycin, and 3-MA can repress cell proliferation in both BRAF V600E and BRAF WT cell lines. Further investigation with qPCR and western blot showed that eIF4E expression can be significantly downregulated at the mRNA and protein levels with inhibition of autophagy. This implies a role for eIF4E in mediating the pro-survival autophagy pathway in melanoma. Moreover, the expression of key autophagy markers, such as Atg5 and LC-3 II have been upregulated in several Vemurafenib resistant cell lines compared to the parental A375. In conclusion, our data show that eIF4E promotes proliferation of some melanoma cell lines. We also show that eIF4E is involved in maintaining the survival of some melanoma cell lines with acquired vemurafenib resistance. These data suggest that therapeutically targeting eIF4E, and disrupting pro-survival autophagy, may be a viable means of inhibiting melanoma cell proliferation and overcoming vemurafenib resistance.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B235.

Citation Format: Yao Zhan, Michael S. Dahabieh, Sonia V. del Rincon, Wilson H. Miller, Jr.. The role of eIF4E in promoting melanoma cell proliferation and maintaining acquired resistance to vemurafenib in melanoma. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B235.
Abstract B238: PIN1 (Peptidyl-prolyl cis/trans-isomerase, NIMA-interacting 1) is a potential therapeutic target for EBV-associated nasopharyngeal carcinoma.
Authors: Xu Meng , Chow Chit , Cheung Chartia Ching Mei , Chung Grace Tin-Yun , Lo Kwok Wai
Published: August 2014

Nasopharyngeal carcinoma (NPC) is a common EBV-associated human malignancy in Southern China. NPC is highly radiosensitive and radiotherapy is the mainstay treatment for the patients. However, poor clinical outcome remains the major concern in NPC patients with advanced stage disease. Development of new clinical interventions to treat the disease are importance for control this cancer. PIN1 is a highly conserved enzyme that isomerizes specific phosphorylated Ser/Thr-Pro bonds in multiple proteins. It induces conformational changes and modulates functions of many proteins that promote oncogenesis. We have recently confirmed the high PIN1 expression in almost all NPC primary tumours. The aim of this study was to investigate the potential of PIN1 as a therapeutic target for the treatment of NPC. The oncogenic function of PIN1 was investigated in the EBV-positive NPC cell line C666-1 and an immortalized NP epithelial cells NP69. The antitumor effect of PIN1 inhibition was then studied in both in vitro and in vivo NPC models by using the PIN1 inhibitor juglone. In the stable PIN1-expressing NP cells, we found the upregulation of cyclin D1 and activation of MAPL/JNK pathway. Furthermore, we also demonstrated the interaction between PIN1 and EBNA1 in the NPC cells. PIN1 was also shown to interfere the transcription activity of EBNA1 through binding to the phosphorylation sites of EBNA1. Notably, knockdown of PIN1 by siRNA significantly inhibited cell proliferation, DNA synthesis and colony formation of NPC cells. Treatment with juglone demonstrated significant induction of apoptosis and suppression of cyclin D1 expression in C666-1 cells. The IC50 of C666-1 was approximately 6 μM while that of EBV-negative NPC cells HK-1was 10 μM. A dose-dependent inhibition of tumor growth was observed in mice treated with juglone. A significantly growth suppression and cyclin D1 downregulation was found in the tumours of the mice treated with 1-1.5 mg/kg juglone. In conclusion, our findings imply that targeting Pin1 may serve as a potential therapeutic approach for treating patients suffering from this EBV-associated cancer.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B238.

Citation Format: Meng Xu, Chit Chow, Chartia Ching Mei Cheung, Grace Tin-Yun Chung, Kwok Wai Lo. PIN1 (Peptidyl-prolyl cis/trans-isomerase, NIMA-interacting 1) is a potential therapeutic target for EBV-associated nasopharyngeal carcinoma. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B238.
Abstract B240: Novel protein fusion toxins targeting c-kit positive neuroendocrine tumors.
Authors: Choudhary Swati , Pardo Alessa , Rosinke Reinhard , Barth Stefan , Batra Janendra K. , Verma Rama S.
Published: August 2014

Currently, the treatment options for patients with neuroendocrine carcinomas (NECs) are limited. Stem cell factor is found to have a trophic role in neuroendocrine cancer cells through an autocrine growth loop, which leads to the activation of the c-kit receptor. NECs like neuroblastomas, small cell lung carcinomas and poorly differentiated human colon carcinoma cells (CRCs) over-express both the c-kit receptor and its ligand, stem cell factor (SCF), as compared to normal cells. The role of the known c-kit inhibitor imatinib has already been investigated in these cell types and has shown promising results. We developed SCF-based c-kit targeting protein fusion toxins against neuroendocrine carcinomas, such as neuroblastomas and colorectal carcinomas. In this study, SCF was cloned from the HepG2 cell line and mutated in order to optimize its expression. The mutated SCF was recombinantly fused with bacterial toxins (Diphtheria toxin (DT) and Pseudomonas exotoxin A (PE)) to form c-kit targeting fusion toxins. These proteins were expressed in E.coli and purified by affinity chromatography followed by size exclusion chromatography. Flow cytometric analysis was used to monitor receptor expression on c-kit positive neuroblastoma cell lines (IMR 32 and SHSY5Y), colon carcinoma cell lines (HT-29, HCT 116 and DLD-1), and the c-kit negative cell line, MCF-7. In vitro binding, internalization and toxicity studies were performed on the above cell lines in order to characterize the purified chimeric toxins. Annexin V binding assays and cell cycle analysis were performed additionally, to prove their efficacy. The ID50 values for the toxins were found to correlate with the receptor expression on these cell lines. The novel c-kit targeting protein fusion toxins reported in our study offer a promising strategy for therapeutics against neuroendocrine tumors and warrant further testing in such tumors with c-kit autocrine and paracrine loops.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B240.

Citation Format: Swati Choudhary, Alessa Pardo, Reinhard Rosinke, Stefan Barth, Janendra K. Batra, Rama S. Verma. Novel protein fusion toxins targeting c-kit positive neuroendocrine tumors. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B240.
Abstract B241: Bispecific antibody targeting EGFR and cMet demonstrates superior activity compared to the combination of single pathway inhibitors.
Authors: Moores Sheri , Chiu Mark , Bushey Barbara , Chevalier Kristen , Chin Diana , Chippari Susan , Haytko Peter , McCabe Frank , Neijssen Joost , Parren Paul , Schuurman Janine , Wu Sam , Attar Ricardo , Anderson Mark
Published: August 2014

Many tumors respond initially to targeted therapy, only to develop resistance over time thereby allowing the tumors to progress. In patients treated with EGFR small molecule inhibitors, the cMet pathway is often upregulated, either through MET gene amplification or an increase in the ligand HGF, to compensate and provide resistance to the EGFR monotherapy. Because both EGFR and cMet signal through some of the same survival and growth-promoting pathways, dual inhibition of these receptors may improve efficacy and prevent resistance through these mechanisms. We have designed a bispecific EGFR-cMet antibody (EM1-mAb) with multiple mechanisms of action resulting in superior activity compared to a combination of single EGFR and cMet inhibitors. Fab arm exchange was used to produce EM1-mAb, a technique that allows for efficient large-scale preparation of bispecific antibodies. EM1-mAb prevented binding of the ligands EGF and HGF to their respective receptors, EGFR (IC50 = 10 nM) and cMet (IC50 = 30 nM). Ligand-induced phosphorylation of each receptor was inhibited in cell-based assays. Blocking signaling from both EGFR and cMet with a combination of single monospecific antibodies resulted in an enhanced inhibition of pERK, a downstream effector of both receptors. The bispecific EM1-mAb further increased the potency of inhibition of pERK (55-65-fold) compared to the combination of single monospecific antibodies, suggesting an avidity effect on downstream signaling. EM1-mAb was evaluated in SCID-beige mice implanted with tumor cells engineered to express human HGF. Complete regression of 8/8 tumors was observed upon treatment with EM1-mAb dosed twice a week at 20 mg/kg. After the dosing period of four weeks, mice were monitored for an additional 10 weeks and no tumor regrowth was observed.

Our data demonstrate that the bispecific antibody EM1-mAb, generated using Fab arm exchange, inhibited EGFR and cMet pathways simultaneously, resulting in superior activity in cellular downstream signaling compared to the combination of single pathway inhibitors. These attributes allow for a more efficient path toward clinical development.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B241.

Citation Format: Sheri Moores, Mark Chiu, Barbara Bushey, Kristen Chevalier, Diana Chin, Susan Chippari, Peter Haytko, Frank McCabe, Joost Neijssen, Paul Parren, Janine Schuurman, Sam Wu, Ricardo Attar, Mark Anderson. Bispecific antibody targeting EGFR and cMet demonstrates superior activity compared to the combination of single pathway inhibitors. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B241.
Abstract B250: Evaluation of anticancer efficacy of 6-propionylpterin characterized from native isolate Bacillus subtilis.
Authors: Nisshanthini S D. , Sukirtha R. , Achiraman S. , Palaniswamy M. , Jayaraman Angayarkanni
Published: August 2014

In this context the present study is aimed at purifying a pteridine derivative and studying its apoptotic effect on a cancer cell line. 6-propionyl pterin have been purified from a native strain of Bacillus subtilis and administered via intra peritoneal injection to DLA induced mice. During the course of the experiment reduction in angiogenesis was visualized. Earlier report (Kim et.al., 2011) clearly suggested that sepiapterin, a precursor of tetrahydrobiopterin inhibits VEGF-A induced HUVEC proliferation and adhesion through down-regulation of VEGFR-2 downstream signaling pathways, independently of NO synthesis and this supported the present finding. Based on our preconceived view that administration of 6-pp enhances the activity of iNOS, thereby enhanced production of nitric oxide (NO), an attempt was made to check the pathway of NO induced apoptosis. The expression of iNOS, p53, caspase 3, and mdm2 gene were checked by RT PCR. But only mdm2 gene expression alone was upregulated. p53 downregulation might be due to Mdm2 which block its transcriptional activity, favours its nuclear export and stimulates its degradation (Chene, 2003). Caspase 3 activation does not participate in Mdm2 induced apoptosis as determined by the protein levels or poly (ADP-ribose) polymerase fragmentation (Dilla et al., 2000). The report of Wolf et al., 1999 strongly suggests that caspase 3 is the primary activator of apoptotic DNA fragmentation. This is inconsistent with our present finding wherein there was absence of DNA fragmentation in apoptotic cells and also expression of caspase 3 was absent. Thus overall mechanism may be initiated by expression of Mdm2 which inturn inhibited p53 expression. Mdm2 might have down regulated Bcl2 followed by a cascade of Caspase 2 and Cyt-c expression. Cyt-c activation might have regulated Caspase -7 and ROCK protein. ROCK is responsible for cell shrinking and membrane blebbing and finally leading to apoptosis. Caspase 3 activation does not participate in Mdm2 induced apoptosis and hence DNA fragmentation is not found. This study was done to evaluate the efficacy of the compound as anticancer agent and whether it induces apoptosis or not. Mechanism of action of drug was predicted from the results obtained. To derive the exact mechanism further study on the signaling proteins has to be performed.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B250.

Citation Format: S D. Nisshanthini, R. Sukirtha, S. Achiraman, M. Palaniswamy, Angayarkanni Jayaraman. Evaluation of anticancer efficacy of 6-propionylpterin characterized from native isolate Bacillus subtilis. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B250.