bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 4727: ST7612AA1: focus on a drug candidate, front-runner of a new generation of HDAC inhibitors
Authors: Giannini Giuseppe , Milazzo Ferdinando Maria , Battistuzzi Gianfranco , Vesci Loredana
Published: July 2016

After more than 20 years of research in the field of HDAC inhibitors, the oncological armamentarium has significantly enriched with new approved drugs. Currently, four drugs, Vorinostat (Zolinza; 2006), Romidepsin (Istodax; 2009) Belinostat (Beleodaq; 2014) and Panobinostat (Farydak; 2015) have been approved by the U.S. Food and Drug Administration (FDA) for the treatment of cutaneous T-cell lymphoma (CTCL), peripheral T-cell lymphoma (PTCL), and multiple myeloma, respectively. A fifth, Chidamide (Epidaza; 2015), has been recently approved by the China Food and Drug Administration for the treatment of PTCL.

Beyond them, more than twenty are currently under pre-clinical and clinical investigation as single agent and in combination therapies against different cancers and in other several novel therapeutic indications. However, it is to emphasize a feature: among all these, no one, with the exception of the natural product Romidepsin, is a thiol derivative.

After efforts lasted years, now we have selected ST7612AA1 - a new thiol-ω(γ-lactam amide) SAHA analogues, potential front-runner of a new generation of HDAC inhibitors, [1] highly competitive respect to other HDAC inhibitors drugs, orally administered with a negligible toxicity.

ST7612AA1 displays low-nanomolar inhibitor activity on HDACs, being especially powerful on HDAC6 isoform, associated to a wide spectrum of antitumor activity, both in vitro and in vivo [2]; it can be industrially developed with a quick and easy synthetic process [3]. Moreover, it has also been investigated as an enhancer in antiretroviral therapy against HIV, aimed to eradicate the viral reservoirs [4].

All these results encouraged further enrichment experiments with ST7612AA1 as a drug candidate, which is currently in a phase of pre-clinical evaluation.

The overall profile of ST7612AA1, including synthesis and a comprehensive pharmacological characterization, will be presented.

[1] G. Giannini et al. J Med Chem. 2014, 57, 8358-8377

[2] L. Vesci et al. Oncotarget 2015, 6, 5735-48

[3] G. Battistuzzi, G. Giannini. Bioorg. Med. Chem .Lett. 2015, submitted

[4] R. Badia Antiviral Research 2015, 123, 62-69

Citation Format: Giuseppe Giannini, Ferdinando Maria Milazzo, Gianfranco Battistuzzi, Loredana Vesci. ST7612AA1: focus on a drug candidate, front-runner of a new generation of HDAC inhibitors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4727.
Abstract 4737: New platinum (Pt)-based anticancer agents, bearing a PtN2SO coordination core, for treating advanced melanoma
Authors: To Kenneth K.W. , Chong Peace , Au-Yeung. Steve C.F.
Published: July 2016

The aim of this project is to demonstrate the potential utility of a new series of platinum (Pt) compounds having a PtN2SO coordination core in treating advanced melanoma. There is currently an unsatisfied medical need for a more effective treatment of advanced melanoma, which is notorious for its prominent resistance to conventional chemotherapeutic drugs due to elevated DNA repair capacity and dysregulation of cancer apoptotic pathways. Platinum (Pt)-based anticancer drugs, exemplified by cisplatin, are key component in combination chemotherapy. They bind to DNA and form mainly the DNA-Pt bifunctional crosslink, subsequently leading to apoptosis to mediate cell death. A series of new Pt(II) compounds possessing a bidentate ligand modified from oxaliplatin has been synthesized, with one of the oxygen ligating atom substituted for a sulfur atom (resulting in a PtN2SO coordination core structure). This novel design is to minimize competition from protein and other bionucleophiles for the Pt drug but maximize drug-DNA interaction. We hypothesize that the unique features of the new PtN2SO compounds may make them good candidates for treating advanced melanoma by (i) overcoming DNA repair-mediated drug resistance; and (ii) generating excess reactive oxygen species (ROS) to selectively trigger apoptosis in melanoma cells. The new compounds were found to be more cytotoxic than cisplatin in a panel of human and mouse melanoma cell lines. Importantly, the new compounds were also found to be minimally affected by Pt resistance, which is presumably caused by the formation of unique DNA-Pt monoadduct and reduced DNA repair. DNA-platination study in melanoma cell lines revealed that the new PtN2SO compounds are able to form more DNA-Pt adducts and there was less repair than treatment with cisplatin. The new compounds were also found to cause a greater induction of the MAPKs (p38, JNK and ERK) than cisplatin to mediate apoptosis. On the other hand, at equipotent concentration, some of the new Pt compounds were found to generate more ROS than cisplatin as indicated by a general fluorescent dye-based oxidative stress indicator. Interestingly, the cytotoxicity of the new compounds were blocked to a greater extent than cisplatin by ROS scavengers, suggesting a more prominent role played by ROS in mediating the cytotoxicity of the new compounds. Our study thus advocates further investigation of the new PtN2SO compounds in treating advanced melanoma.

Citation Format: Kenneth K.W. To, Peace Chong, Steve C.F. Au-Yeung. New platinum (Pt)-based anticancer agents, bearing a PtN2SO coordination core, for treating advanced melanoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4737.
Abstract 4742: Comparison of enhancement of the antitumor effect of CDDP by PXR antagonists
Authors: Kishimoto Shuichi , Yasuda Megumi , Tomita Megumi , Yamane Yuki , Suzuki Ryosuke , Fukushima Shoji
Published: July 2016

We have already found that a nuclear receptor PXR can modulate the cytotoxicity of CDDP for cancer cells, and ketoconazole, a PXT antagonist, can be an agent enhancing the antitumor activity of CDDP due to increase of the intracellular platinum content as the mechanism. However, nuclear receptor ligands have a variety of functions, and there is a possibility that PXR antagonist may enhance the cytotoxicity of CDDP through the mechanism other than the inhibition of transporter-mediated efflux of CDDP. The goal of this study was to compare the enhancing ability of three PXR antagonists, ketoconazole (KTZ), phenethyl isothiocyanate (PEITC) and metformin (MFM), for the antitumor effect of CDDP and clarify the contribution of inhibition of the efflux transporter as the mechanism of PXR antagonist. Cell lines used in this study were human hepatoma cell line HepG2. Changes in mRNA expression were assessed by real-time RT-PCR, and the ability of apoptosis induction was assessed as caspase-3 activity. Total intracellular platinum contents were determined by ICP-AES. When HepG2 cells were treated for 24 hr with 10 μM of CDDP, no change of caspase-3 activity was observed when compared to control cells. Also, 30 μM of KTZ, 30 μM of PEITC or 5 mM of MFM had no affect on the caspase-3 activity in treated cells compared with control cells. When KTZ, PEITC or MFM was exposed to HepG2 cells from 24 hr before treatment and during 24-hr treatment with 10 μM of CDDP, the caspase-3 activity was significantly increased to 461%, 355% and 326% of the control, respectively, in comparison with that in CDDP alone. When HepG2 cells were treated for 8 hr with 25 μM of CDDP, the intracellular platinum content was 110 ng/mg protein. On the other hand when KTZ, PEITC or MFM was exposed to HepG2 cells from 24 hr before treatment and during 8-hr treatment with 25 μM of CDDP, the intracellular platinum content was apparently increased to 227%, 491% and 161% of CDDP alone, respectively. Three PXR antagonists resulted in an increase in the intracellular platinum content that seems to be due to inhibition of the platinum efflux transporter, but there is no correlation between increase in intracellular platinum content and enhancement of antitumor activity by PXR antagonists. These results concluded that PXR antagonist can be an agent enhancing the antitumor activity of CDDP, but the ability of PXR antagonist for enhancing antitumor activity of CDDP can not be determined from only the increase in the intracellular platinum content.

Citation Format: Shuichi Kishimoto, Megumi Yasuda, Megumi Tomita, Yuki Yamane, Ryosuke Suzuki, Shoji Fukushima. Comparison of enhancement of the antitumor effect of CDDP by PXR antagonists. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4742.
Abstract 4753: Ovarian cancer stem cell marker ALDH1A2 is a candidate biomarker for patient selection for intraperitoneal chemotherapy
Authors: Seagle Brandon-Luke L. , Dandapani Monica , Luo Chen Hui , Hoppenot Claire , Samuelson Robert , Eng Kevin H. , Odunsi Kunle , Shahabi Shohreh
Published: July 2016

Objective. To evaluate ovarian cancer stem cells as predictors of survival we analyzed associations of cancer stem cell markers ALDH1, CD117 and CD133 with survival outcomes among patients with high grade serous ovarian cancer (HGS OvCa).

Methods. Data from HGS OvCa patients who were surgically staged prior to treatment with IP (n = 90) or IV-only (n = 398) chemotherapy was obtained from The Cancer Genome Atlas. Multivariate Cox proportional-hazards regression tested associations of tumor mRNA expression of 5 cancer stem cell markers with progression free survival (PFS) and overall survival (OS). Expression was analyzed as a continuous variable by restricted mean survival (RMS) analysis. Mean PFS or OS were compared between IP and IV groups by permutation testing stratified by expression. P-values were two-tailed.

Results. Increased tumor ALDH1A2 expression was associated with decreased OS among patients treated with IP chemotherapy, HR 2.36 (1.16-4.80), p = 0.017. IP treated patients with upper 20th percentile ALDH1A2 expression had decreased OS compared to bottom 20th percentile expression (30.4 versus 51.1 months, -20.7 months difference, p = 0.017). RMS curves for PFS and OS of IP versus IV treated patients crossed at high ALDH1A2 expression, indicating that IP treated patients had decreased survival compared to IV-only treated patients. Patients with upper 20th percentile ALDH1A2 expression treated with IP versus IV-only chemotherapy had no difference in mean PFS (21.3 versus 21.6 months, -0.3 months difference, p = 0.67) and decreased OS (30.4 versus 35.3 months, -4.9 months difference, p < 0.0001). Upper 10th percentile ALDH1A2 expression was associated with decreased PFS (19.5 versus 22.0 months, -2.5 months, p = 0.005) and OS (27.1 versus 35.2 months, -8.1 months, p < 0.0001) comparing IP versus IV groups. Increased CD133 expression was associated with increased PFS among IV-only patients, HR 0.85 (0.74-0.97), p = 0.016. CD117 and the ALDH1 genes ALDH1A1/3 were not associated with survival.

Conclusions. High primary tumor ALDH1A2 expression was independently associated with significantly decreased OS among patients treated with IP chemotherapy. High ALDH1A2 was associated with lack of benefit or decreased survival among patients treated with IP compared to IV-only adjuvant chemotherapy.

Citation Format: Brandon-Luke L. Seagle, Monica Dandapani, Chen Hui Luo, Claire Hoppenot, Robert Samuelson, Kevin H. Eng, Kunle Odunsi, Shohreh Shahabi. Ovarian cancer stem cell marker ALDH1A2 is a candidate biomarker for patient selection for intraperitoneal chemotherapy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4753.
Abstract 4754: Overexpression of TSH and ERBB2 (HER2) receptors is associated with sharply decreased survival in high grade serous ovarian cancer
Authors: Seagle Brandon-Luke L. , Dandapani Monica , Luo Chen Hui , Hoppenot Claire , Samuelson Robert , Eng Kevin H. , Odunsi Kunle , Shahabi Shohreh
Published: July 2016

Objective. To test if hormone or growth factor receptor expression is associated with survival among patients with high grade serous ovarian cancer (HGS OvCa) we analyzed tumor mRNA expression microarray and clinical data from The Cancer Genome Atlas (TCGA).

Methods. HGS OvCa patients were surgically staged prior to treatment with IP (n = 90) or IV-only (n = 398) chemotherapy. Multivariate Cox proportional-hazards regression tested associations of expression of 9 hormone or growth factor receptors with progression free survival (PFS) and overall survival (OS). Hazard ratios are hazard per each one standard deviation increase in gene expression. Expression was analyzed as a continuous variable by restricted mean survival analysis. Mean PFS or OS were compared between IP and IV groups by permutation testing stratified by expression. P-values were two-tailed.

Results. Expression of ESR1, PGR, FSHR, LHCGR, MET, and EGFR were not associated with PFS or OS. TSHR expression was associated with decreased OS (HR 1.22 (1.06-1.41), p = 0.005) and PFS (HR 1.18 (1.05-1.33), p = 0.006) among IV-only treated patients. ERBB2 expression was associated with decreased OS (HR 1.48 (1.05-2.10), p = 0.027) among patients who received IP chemotherapy. Using multigene (ESR2, PGR, TSHR, and ERBB2) analysis, among the IP group, ERBB2 (HR 1.76 (1.11-2.79), p = 0.015) and ESR2 (HR 0.28 (0.08-0.93), p = 0.037) were associated with OS. Only TSHR expression was associated with decreased OS (HR 1.22 (1.06-1.41), p = 0.005) and decreased PFS (HR 1.18 (1.05-1.33), p = 0.007) on multigene analysis of IV-only treated patients. OS and PFS decreased steeply at high expression of TSHR and ERBB2. Among patients with upper 10th percentile TSHR expression, no significant difference in mean OS or PFS was observed between patients treated with IP versus IV-only chemotherapy. Patients with lower TSHR expression (< 90% percentile) experienced a mean 13.7-month increased OS and 16.4-month increased PFS associated with IP chemotherapy (p < 0.0001).

Conclusions. Among HGS OvCa patients treated with IV-only chemotherapy, increased tumor TSHR expression was associated with decreased OS and PFS. High TSHR expression characterized patients who did not benefit from IP chemotherapy.

Citation Format: Brandon-Luke L. Seagle, Monica Dandapani, Chen Hui Luo, Claire Hoppenot, Robert Samuelson, Kevin H. Eng, Kunle Odunsi, Shohreh Shahabi. Overexpression of TSH and ERBB2 (HER2) receptors is associated with sharply decreased survival in high grade serous ovarian cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4754.
Abstract 476: Differential prognostic value of MYC immunohistochemistry in papillary RCC subtypes
Authors: Bellut Julia , Bertz Simone , Nolte Elke , Stoehr Christine , Polifka Iris , Herrmann Edwin , Jung Rudolf , Hartmann Arndt , Wullich Bernd , Taubert Helge , Wach Sven
Published: July 2016

Introduction

The histomorphological classification of type 1 and type 2 papillary renal cell carcinomas (pRCCs) has substantially improved the prognostication of patients’ long-term outcome. We previously established microRNA (miRNA) expression profiles of type1 and type 2 pRCCs and, based upon the results, hypothesize a differential expression of the MYC proto-oncogene in pRCCs.

Material and methods

An multi-institutional tissue microarray with more than 200 histomorphological classified pRCCs was acquired from the PANZAR consortium. Immunohistochemistry for MYC, the MYC-induced nuclear antigen MINA53 and Ki67 was performed. The prognostic value for patients’ long-term survival was examined using uni- and multivariate survival models.

Results

As expected, a pRCC type 2 morphology was associated with reduced overall and cancer-specific survival. Interestingly, pRCCs with a mixed type 1/2 morphology showed an even worse clinical outcome. When combining the pRCC morphology and immunohistochemical staining, only the combination of morphology and MYC staining patterns was able to further sub-stratify the group of pRCC type 1 tumors in a good and worse prognosis group. None of the patients with pRCC1 tumors and the favorable MYC staining pattern (>44% of all pRCC type 1 tumors) suffered a tumor-related death. Patients with pRCC type 1 tumors and the adverse MYC staining pattern had an 4.5-fold elevated risk of death (multivariate corrected for pathological tumor stage).

Conclusions

Although a pRCC type 1 histomorphology is regarded as a favorable prognostic factor, associated with good clinical outcome, still patients die of tumor-related causes. We conclude, that in particular for patients with pRCC type 1 tumors, MYC immunohistochemistry is able to provide additional prognostic information for a sub-stratification of this patient population. This knowledge could be used for the establishment of risk-stratified follow-up schemes for patients after surgical treatment.

Citation Format: Julia Bellut, Simone Bertz, Elke Nolte, Christine Stoehr, Iris Polifka, Edwin Herrmann, Rudolf Jung, Arndt Hartmann, Bernd Wullich, Helge Taubert, Sven Wach. Differential prognostic value of MYC immunohistochemistry in papillary RCC subtypes. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 476.
Abstract 4761: Translational regulation by eIF4E and its contribution to tamoxifen resistance in breast cancer
Authors: Gong Chun , Mok Ka Chun , CHEUNG Yuen-Nei , Man Pui-Sum , Lam EWF , Khoo Ui-Soon
Published: July 2016

Breast cancer is one of the prevalent causes of cancer in women and its occurrence has been rising in the last few decades. Two thirds of breast cancer patients are ER-positive and can receive tamoxifen (TAM) treatment. Unfortunately, many of the patients eventually develop resistance to tamoxifen. Identifying a molecular marker associated with tamoxifen resistance would help in designing better therapeutic strategies to overcome this. In eukaryotes, translation initiation is the most regulated step. Abnormal translation machinery underlies a variety of human diseases including cancers. Eukaryotic translation initiation factor 4E (eIF4E) is the least abundant initiation factor and is believed to be the rate limiting step for translation initiation. Overexpression of eIF4E in cells selectively promotes translation of mRNAs involved in cell proliferation, apoptosis and tumor progression. Recently, eIF4E overexpression has been implicated in drug resistance in melanoma1. We hypothesized that eIF4E may also be involved in tamoxifen resistance. The aim of this study was to characterize the role of eIF4E in tamoxifen resistance and identify novel molecular targets that may be translationally regulated.

Immunohistochemistry (IHC) staining of eIF4E showed up-regulation in human breast cancer samples compared with non-tumor counterparts. In silico analysis predicted that ERá and FOXM1 have a long and highly structured 5’-UTR, which are sensitive to the expression level of eIF4E. Polysomal fractionation confirmed that ERá and FOXM1 mRNA were more actively translated in MCF7 than in MCF10A. The correlation between eIF4E and ERá/FOXM1 were further confirmed in tissue microarray (TMA). The role of eIF4E in conferring TAM resistance was studied by MTT assays. Overexpression of eIF4E induced TAM resistance while knockdown eIF4E sensitized cells to TAM. Additionally, overexpression of eIF4E upregulated ERá/FOXM1 expression at protein level while knockdown eIF4E downregulated their expression at protein level.

Our results show that eIF4E induced TAM resistance possibly through translational regulation of ERá/FOXM1. eIF4E is a promising biomarker for anti-estrogen drug responsiveness and a future therapeutic target for treating drug resistant breast cancer patients.

Reference:

1. Zhan Y, et al. The role of eIF4E in response and acquired resistance to vemurafenib in melanoma J Invest Dermatol. 2015 May;135(5):1368-76.

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Citation Format: Chun Gong, Ka Chun Mok, Yuen-Nei CHEUNG, Pui-Sum Man, EWF Lam, Ui-Soon Khoo. Translational regulation by eIF4E and its contribution to tamoxifen resistance in breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4761.
Abstract 4763: Targeted therapy by MET inhibitors against small-cell lung cancer with aberrant activation of HGF/MET pathway
Authors: Taniguchi Hirokazu , Takeuchi Shinji , Fukuda Koji , Yamada Tadaaki , Sakamoto Shuichi , Kawada Manabu , Yano Seiji
Published: July 2016

Small-cell lung cancer (SCLC) is one of the most aggressive malignancy, characterized by rapid growth and metastatic spread to multiple organs. Approximately 70% of SCLC patients have distant metastases at the diagnosis. Recent studies reported some genomic aberrations in SCLC and several molecular target drugs have been evaluated in clinical trials. However, no molecular target agents have been approved yet for SCLC.

Hepatocyte growth factor (HGF), also known as scatter factor, is only one ligand for MET receptor. HGF/MET pathway plays the crucial role in the growth of various types of cancers. The purpose of this study is to examine the role of HGF/MET pathway activation in SCLC and to evaluate therapeutic potential of MET inhibitors, including crizotinib and golvatinib, against metastasized SCLC.

We used eight human SCLC cell lines. Expression of HGF and MET was evaluated by ELISA and western blot, respectively. Cell viability was examined by MTT assay. Four cell lines produced discernible levels of HGF and four cell lines expressed phosphorylated MET, respectively. MET inhibitors, crizotinib and golvatinib, remarkably inhibited the viability of three cell lines, SBC-5, DMS273 and DMS273B1. Knockdown of either MET or HGF by specific siRNA suppressed the growth of these cell lines, indicating that HGF/MET pathway activation is essential for survival of these SCLC cell lines. These observations suggest that MET-TKIs may be useful for a subset of SCLC with aberrant HGF/MET pathway activation.

We recently established in vivo imaging model of multiple organ metastasis (including liver and bone metastases) with SBC-5 cells. We are now evaluating the anti-metastatic effect of MET-TKIs, crizotinib and golvatinib, in the in vivo imaging model. At the annual meeting, we will present the results of MET-TKI treatment and discuss their potential against multiple-organ metastasis produced by SCLC with aberrant HGF/MET pathway activation.

Citation Format: Hirokazu Taniguchi, Shinji Takeuchi, Koji Fukuda, Tadaaki Yamada, Shuichi Sakamoto, Manabu Kawada, Seiji Yano. Targeted therapy by MET inhibitors against small-cell lung cancer with aberrant activation of HGF/MET pathway. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4763.
Abstract 4769: Inhibition of ribosomal protein L9 expression suppresses colorectal carcinoma cell growth in vitro and in vivo
Authors: Baik In Hye , Park Keon Uk , Hwang Ilseon , Ryoo Hun-Mo , Lee Yun-Han
Published: July 2016

Background: Ribosomal protein L9 (RPL9), a component of the 60S subunit, is upregulated in human colorectal cancer (CRC). We thus hypothesized if targeting of RPL9 with small interfering (si) RNA could inhibit CRC progression. We also investigated molecular mechanism to mediate CRC cell death caused by RPL9 silencing. Methods: HCT116 and HT29 human CRC cells were transfected with RPL9 siRNA and tested for growth inhibition and apoptotic induction using MTS, FACS and microscopic analysis. To obtain insights into the molecular changes in response to RPL9 knockdown, global changes in gene expression were examined using RNA sequencing. Results: RPL9 silencing caused inhibition of CRC cell growth through induction of apoptotic cell death. RNA sequencing revealed that RPL9-specific knockdown led to dysregulation of 622 genes in HCT116 and 2882 genes in HT29 cells. Among those, 256 genes showed the same directional regulation (128 up- and 168 down-regulated genes), including up-regulation of tumor suppressors such as KLF6 and ATF3, and were considered as a common RPL9 knockdown signature. Western blotting proved that downregulation of RPL9 was accompanied with the decrease in the levels of PARP-1 and pro-caspase 3 delaying cell cycle progression and accelerating apoptotic signaling. Of importance, targeting RPL9 significantly inhibited CRC growth in a murine xenograft model. Conclusion: These results suggest that inhibition of RPL9 expression could be an attractive option for molecular targeted therapy of colorectal cancer.

Citation Format: In Hye Baik, Keon Uk Park, Ilseon Hwang, Hun-Mo Ryoo, Yun-Han Lee. Inhibition of ribosomal protein L9 expression suppresses colorectal carcinoma cell growth in vitro and in vivo. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4769.
Abstract 4770: The regulation of pre-ribosomal RNA synthesis by LKB1
Authors: Jin Rui , Liu Faken , Liu Xiuju , Huang Henry , Wilkinson Scott C. , Zhong Diansheng , Khuri Fadlo R. , Fu Haian , Marcus Adam I. , He Yulong , Zhou Wei
Published: July 2016

LKB1 is commonly thought of as a tumor suppressor gene, because its hereditary mutation is responsible for a cancer syndrome, and somatic inactivation of LKB1 is found in non-small cell lung cancer, melanoma, and cervical cancers. Unlike other tumor suppressors whose main function is to either suppress cell proliferation or promote cell death, one of the functions of LKB1 is to suppress cell proliferation in order to promote cell survival under energetic stress conditions. We recently discovered that LKB1 promotes pre-ribosomal RNA synthesis under uridine down-regulated condition. The mechanistic basis of this finding is that LKB1 activates TIF-IA-mediated pre-riobosomal RNA synthesis, partly through the control of its cellular localization. Immuno-coprecipitation study revealed that the interaction between TIF-IA and nuclear transportation machinery may be regulated by LKB1. Our finding also has important clinical implication because the suppression of de novo UTP synthesis preferentially promotes apoptosis in LKB1-inactivated cells. This unique, pro-survival function of LKB1 led us to exploit the vulnerability of LKB1-null cells in their defect in sensing intracellular UTP depletion. Such targeted agents represent a novel treatment strategy because they only induce cell killing when LKB1 is absent.

Citation Format: Rui Jin, Faken Liu, Xiuju Liu, Henry Huang, Scott C. Wilkinson, Diansheng Zhong, Fadlo R. Khuri, Haian Fu, Adam I. Marcus, Yulong He, Wei Zhou. The regulation of pre-ribosomal RNA synthesis by LKB1. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4770.
Abstract 4774: Hypoxic bio-reduction of novel NBQ48 in treated tumor cells and the activity of cytochrome P450 reductase
Authors: Zayas Beatriz , Lebron Vivian , Rivera Juan P. , Velez Christian , Cox Osvaldo
Published: July 2016

The main goal of this research was to evaluate the reduction activity of a novel Nitrobenzazolo[3,2-a]quinolinium (NBQ48) compound under hypoxic environment thru the formation of a fluorescent metabolite and further to evaluate the activity of the cytochrome P450 (CYP450) reducatase in the reduction of these compounds. To evaluate the reduction of NBQ48 and the formation of its fluorescent metabolite two (2) tumor cell lines in culture Toledo (lymphoma) and A431 (endothelial) where treated under nitrogen or argon saturated environments to create a hypoxic (low oxygen) environment. In a 15 ml conical tube 4×106 cells in RPMI 1640 media were treated with NBQ 48 (3mM) for a final volume of 5mL and incubated with argon or nitrogen saturated environment at 37ºC, 5%. Cells were exposed at different time periods (0 to 48 hours) to evaluate the effect of exposure time in the reduction of the NBQ48 by detecting the reduced fluorescent product, the amino-substituted ABQ48. In addition NBQ48 treated tumor cells were located inside a hypoxic chamber to evaluate the formation of the fluorescent metabolites indicative of a metabolically active cell. To determine if the CYP450 reductase enzyme is activated in the reduction of the NBQ towards the formation of the ABQ metabolite, an experiment containing the NBQs and the CYP reductases was designed. Four (4) samples were prepared: blank media hypoxic, NBQ experimental hypoxic, positive ABQ spiked and negative aerobic control NBQ. Samples with NBQ48 (0.4mM) were incubated for 24 hours. After the incubation period, fluorescence emissions indicating the reductive fluorescent product were measured using a Modulus fluorometer (blue filter). The results on tumor cells treated with NBQ48 under hypoxic conditions demonstrated reduction and the formation of a fluorescent product, amino-substituted ABQ48. The time dependent increase in fluorescence in comparison with non treated cells indicated that the reduction of the NBQ increased with time. Results on the determination of the activity of CYP450 in the reduction of the NBQ48 indicated that only samples containing the CYP450 showed the formation of a fluorescent species presumably, ABQ48. This study provides evidence of the reduction of NBQ48 and the formation of a fluorescent metabolite thru the activations of the CYP450 reductases. The implemented experimental design could also be used to determine activity of hypoxic tissues with clinical applications.

Citation Format: Beatriz Zayas, Vivian Lebron, Juan P. Rivera, Christian Velez, Osvaldo Cox. Hypoxic bio-reduction of novel NBQ48 in treated tumor cells and the activity of cytochrome P450 reductase. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4774.
Abstract 4780: RXDX-107 exhibits multiple mechanisms of intracellular delivery and results in extensive drug-induced interstrand crosslinks in solid tumor preclinical models
Authors: Martin Leenus , Patel Roopal , Johnson Michael , Cao Jerry , Chua Peter , Walsh Colin , Oliver Jennifer , Multani Pratik , Wild Robert , Lin Ralph , Li Gary G.
Published: July 2016

RXDX-107 is a dodecanol alkyl ester of bendamustine, which is then encapsulated in human serum albumin (HSA) to form nanoparticles. Bendamustine is an alkylating agent that induces interstrand DNA crosslinks (ICLs) and causes cell death via several pathways, including intrinsic apoptosis. The activity of bendamustine in the treatment of solid tumor malignancies has not been impressive, possibly due to the pharmacokinetic and limited biodistribution properties of bendamustine. RXDX-107 was designed to improve tissue biodistribution over bendamustine, which may result in superior efficacy and tolerability in patients with solid tumors. In preclinical studies, RXDX-107 displayed significant anti-tumor activity in multiple solid tumor cell lines, cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) models of advanced solid tumors, such as breast, lung, and ovarian cancer.

In this study, we further evaluated the mechanism of action of RXDX-107, particularly the means of entry and accumulation of drug into tumor cells. We have developed a novel analytical method to precisely quantify both dodecanol alkyl ester of bendamustine and released bendamustine in tissue culture medium and cells. Our data demonstrate that RXDX-107 is transported into cells in three active forms. Firstly, RXDX-107 slowly releases bendamustine into the extracellular medium, and released bendamustine then enters into cells. Secondly, the dodecanol alkyl ester of bendamustine is transported into cells and causes ICLs. And lastly, by measuring macropinocytosis, we also determined that human serum albumin nanoparticles mediate the intracellular entry of RXDX-107. Each of these mechanisms results in the formation of ICLs. In addition, comet assay data demonstrate that RXDX-107 displayed stronger induction of ICLs than bendamustine, and the induced ICLs persist over 48 hours in multiple solid tumor cell lines. Taken together, our data demonstrate that RXDX-107 enters and accumulates into cells via multiple mechanisms, and causes extensive and superior ICLs compared to bendamustine in several solid tumor cell lines, thereby providing a strong rationale for further investigation of this agent in solid tumor indications.

Citation Format: Leenus Martin, Roopal Patel, Michael Johnson, Jerry Cao, Peter Chua, Colin Walsh, Jennifer Oliver, Pratik Multani, Robert Wild, Ralph Lin, Gary G. Li. RXDX-107 exhibits multiple mechanisms of intracellular delivery and results in extensive drug-induced interstrand crosslinks in solid tumor preclinical models. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4780.
Abstract 479: Detection and clinical significance of circulating tumor cells in squamous cell carcinoma of the head and neck
Authors: Chikamatsu Kazuaki , Takahashi Hideyuki , Sakakura Koichi , Toyoda Minoru
Published: July 2016

Background: With a developing tumor, tumor cells shed a variety of substances into the blood stream, such as tumor cells, tumor DNA, or exosomes, and these are considered to be as attractive circulating biomarkers to monitor disease progression in cancer patients. However, impact of circulating tumor cells (CTCs) in squamous cell carcinoma of the head and neck (SCCHN) is still not fully understood. In this study, we show that CTCs are present in the peripheral blood of patients with SCCHN, and then investigate the correlation with clinicopathological factors. Materials and Methods: 7.5mL of peripheral blood was obtained from 32 patients with pathologically and clinically confirmed SCCHN. Samples were run with a CellSieve™ Microfiltration Assay (Creatv MicroTech, Inc., Rockville, MD) using a low-pressure vacuum system. The CTCs captured by the filter were stained with an antibody mixture of FITC-conjugated anti-CK 8, 18, and 19, PE-conjugated anti-EpCAM, and Cyanine 5-conjugated anti-CD45. Cells that stained positive for DAPI and CK but negative for CD45, were identified as CTCs. Results: The CTCs were found in 29 (90.6%) of 32 patients. Although there was no association between the number of CTCs and tumor sites, the number of CTCs in patients with advanced disease (stage III/IV) was significantly increased, as compared with those with early disease (stage I/II) (p<0.05). Furthermore, patients with T3/4 had higher number of CTCs compared to patients with T1/2 (p<0.01). Meanwhile, nodal status was not significantly associated with the number of CTCs. In 12 of 32 patients tested, the number of CTCs after treatments was also evaluated. As expected, the number of CTCs was significantly decreased after treatments, regardless of the treatment modalities. Conclusion: Our results suggest that microfiltration is very efficient in capturing CTCs from SCCHN patients. Moreover, CTCs analysis in SCCHN may provide useful information for assessment of treatment efficacy.

Citation Format: Kazuaki Chikamatsu, Hideyuki Takahashi, Koichi Sakakura, Minoru Toyoda. Detection and clinical significance of circulating tumor cells in squamous cell carcinoma of the head and neck. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 479.
Abstract 4796: BTK inhibitor BGB-3111 synergizes with lenalidomide in MCL models
Authors: Hu Nan , Zhang Shuo , He Min , Zhang Jiye , Jiang Bin , Sun Zhijian , Luo Lusong , Wang Lai
Published: July 2016

Background

BGB-3111 is a novel, irreversible, second generation BTK inhibitor with better selectivity profile and DMPK property compared to ibrutinib. It has demonstrated promising anti-tumor activities in patients with advanced B cell malignancies, including mantle cell lymphoma (MCL). Lenalidomide is an immunomodulatory agent with single-agent activity in several histologic subtypes of B-cell non-Hodgkin lymphoma (NHL). It was approved for the treatment of patients with MCL whose disease has relapsed or progressed after two prior therapies, one of which included bortezomib. In this study, we sought to investigate the combination activities of BGB-3111 and lenalidomide in MCL models.

Methods

In vitro drug efficacy was determined using MCL cell lines including REC-1, MINO and JEKO-1. Cell viability was assessed with Cell Titer Glo® assay and half maximal inhibitory concentrations (IC50) were estimated upon exposure to single agents or drug combinations. In vivo activity was assessed in REC-1 and MINO subcutaneous mouse xenograft models. Treatments were administered by oral gavage when tumors were palpable and individual body weight and tumor volume was recorded twice weekly.

Results

The in vitro combination activity of BGB-3111 and lenalidomide was tested in MCL cell lines. Strong synergy was observed in REC-1 and MINO cells, but not in JEKO-1 cells. When tested in vivo, both BGB-3111 (7.5 mg/kg, BID) and lenalidomide (30 mg/kg, QD) significantly inhibited the REC-1 xenograft tumor growth with TGI of 86% and 56%, respectively. The combination treatment resulted in 100% TGI. In MINO xenograft model, combination treatment of BGB-3111 (30 mg/kg, BID) and lenalidomide (30 mg/kg, QD) was also more efficacious than either single agent.

Conclusions

In summary, BGB-3111 and lenlidomide showed interesting in vitro and in vivo combination activity in MCL models, providing rationale for testing this combination in clinic.

Citation Format: Nan Hu, Shuo Zhang, Min He, Jiye Zhang, Bin Jiang, Zhijian Sun, Lusong Luo, Lai Wang. BTK inhibitor BGB-3111 synergizes with lenalidomide in MCL models. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4796.
Abstract 4803: A novel class of phenylacrylonitrile-based small molecules selectively induce double-strand DNA damage in breast cancer cells
Authors: Sakoff Jennette A. , Gilbert Jayne , De Iuliis Geoff , McCluskey Adam
Published: July 2016

We have discovered a class of phenylacrylonitrile-based small molecules that selectively target breast cancer cell lines while having little to no effect on normal breast cancer cells or on cell lines derived from other tumour types including colon, ovarian, lung, skin, prostate and pancreatic carcinomas, neuroblastoma and glioblastoma. Indeed these molecules show more than 200-fold selectivity towards breast cancer cells compared with other tumour types, while maintaining nM potency, as determined by the MTT growth inhibition (GI50) assay with GI50 values of 0.2-2.0μM (72h exposure). Moreover, the sensitive breast cancer cell lines represent tumour types from the four main breast cancer classifications including ER+ luminal A (MCF-7, T47-D and ZR-75-1 cells), ER+ luminal B (BT-474), HER2+ (SKBR-3), and most importantly the Basal (triple negative MDA-MB-468 and BT20) classification which traditionally carries a very poor prognosis. Our novel class of molecules also retain activity in MCF-7/VP16 cells (GI50 0.2μM) which overexpresses the drug resistance ABCC1 gene. Only one breast cancer cell line has shown insensitivity, MDA-MB-231 (Basal triple negative), which unlike all of the other breast cell types has amplifying mutations in KRas and BRaf activity, a genotype found in less than 5% of breast cancer tumours. Furthermore, our novel compounds induce minimal effects on the growth of normal MCF10A breast cells.

Analysis of our most sensitive breast cancer cell line (MDA-MB-468) shows a significant increase in gammaH2AX within 12h of exposure to our lead phenylacrylonitrile molecule, indicative of DNA double strand breakage. This response is concomitant with an increase in the phosphorylation of the cell cycle check point activator CHK2. Cell cycle analysis shows an increase in the proportion of cells in the S-phase of the cell cycle within 24h of exposure, concomitant with a decrease in the proportion of cells in the G1-phase, and preceding an increase in the sub-G1 cell death population. The ability to specifically target breast tumours, while having little or no effect on normal breast cells, or other tumour types is a unique finding. Elucidating the mechanism controlling this phenomenon is now the focus of our research efforts.

Citation Format: Jennette A. Sakoff, Jayne Gilbert, Geoff De Iuliis, Adam McCluskey. A novel class of phenylacrylonitrile-based small molecules selectively induce double-strand DNA damage in breast cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4803.
Abstract 4807: Triphenylmethanol conjugates of triptorelin as anti-cancer prodrugs
Authors: Beni Ryan , Boadi William , Alnakhli Jawzah
Published: July 2016

Triptorelin (TRP) is an anti-cancer agent used for the treatment of a wide variety of hormone-responsive cancers, such as prostate cancer. The surge of testosterone, known as a flare effect, is the major side-effect of cancer chemotherapy using TRP in a combination regiment. Improving the biological activity of TRP by increasing the cellular uptake and retention is a remedy to this end. In this study, the hydrophobicity of TRP was optimized by using an appropriate hydrophobic linker attached to tris(4-methoxyphenyl)methanol (TPM) derivatives with the expectation to improve the cellular uptake. In this regard, a number of TRP conjugates of TPM derivatives with optimized hydrophobicity were synthesized by the reaction of 2-substituted methoxy benzenes (e.g. methyl 2-methoxybenzoate, 1,2-dimethoxybenzene, methoxy-2-methylbenzene, methoxy-2-nitrobenzene, chloro-2-methxyenzene), and 1,3,5-trioxane, followed by the conjugation with TRP and decanedioic acid in the presence of HBTU/DIPEA/DIC in moderate yields. Comparative antiproliferative assays between TPM-TRP conjugates and the corresponding non-covalent physical mixtures of the TPM derivatives and TRP were performed against human acute lymphoblastic leukemia (CCRF-CEM), human ovarian adenocarcinoma (SK-OV-3), and mouse pre adipocytes (3T3-L1) cells. TPM-TRP conjugates inhibited the cell proliferation of CCRF-CEM, SK-OV-3 and 3T3-L1 cells by 55-92%, 24-73%, 37-56%, respectively, at a concentration of 10-50 μM after 24-72 h of incubation. These data suggest that TPM-TRP derivatives with optimized hydrophobicity can be used to improve the biological activity of TRP.

Citation Format: Ryan Beni, William Boadi, Jawzah Alnakhli. Triphenylmethanol conjugates of triptorelin as anti-cancer prodrugs. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4807.
Abstract 4810: Histone deacetylase 2 is a potential determinant of the sensitivity of hepatocellular carcinoma cells to sorafenib
Authors: Kim Hyung Seok , Eun Jung Woo , Shen Qingyu , Shin Woo Chan , Yang Hee Doo , Kim Sang Yeon , Nam Suk Woo
Published: July 2016

Hepatocellular carcinoma (HCC) is the fifth frequently diagnosed cancer and is the second leading cause of cancer death worldwide. Many groups have suggested possible clinical applications for liver cancer therapy but sorafenib, an orally-available kinase inhibitor, is the only standard systematic therapeutics for treatment of hepatocellular carcinoma. However, survival benefit of sorafenib is unsatisfactory due to high level heterogeneity of individual response. We previously reported that histone deacetylase 2 (HDAC2) was deregulated in HCC, and thereby contributed to liver tumorigenesis by enhancing mitotic and metastatic potential of transformed cells. Targeted-disruption of HDAC2 suppressed in vitro and in vivo tumorgigenic potential of HDAC2 in liver cancer. The goal of this study was to investigate whether both sorafenib treatment and HDAC2 inhibition elicit synergistic anti-tumor effect against HCC cells. Here, we showed that sorafenib effectively blocked ERK/MEK and AKT signaling pathway upon EGF stimulation in liver cancer cell lines. Also, we found that valproic acid (VPA), a selective inhibitor of histone deacetylase family I, and sorafenib treatment synergistically evoked liver cancer cell growth retardation. This effect was recapitulated by HDAC2 knockdown with sorafenib treatment and exhibited synergistic effect on apoptotic cell death of liver cancer cell lines, Hep3B and Huh7, compared to single treatment of sorafenib. Our data suggest that combined sorafenib treatment with HDAC2 targeting may provide more benefits toward HCC therapy providing a novel approach for future application in patients with advanced HCC.

Citation Format: Hyung Seok Kim, Jung Woo Eun, Qingyu Shen, Woo Chan Shin, Hee Doo Yang, Sang Yeon Kim, Suk Woo Nam. Histone deacetylase 2 is a potential determinant of the sensitivity of hepatocellular carcinoma cells to sorafenib. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4810.