bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5484: Dehydroleucodine: A potential sesquiterpene lactone for targeting castration-resistant prostate cancer
Authors: Banerjee Souresh , Munirathinam Gnanasekar
Published: May 2015

Prostate cancer (PCa) patients undergoing standard androgen deprivation therapy eventually develop aggressive castration-resistant prostate cancer (CRPC) for which there is no effective treatment currently available. Hence, there is an urgent need to identify effective treatment strategy for lethal CRPC. Previous studies have shown naturally occurring sesquiterpene lactones (SLs) are promising anti-cancer agents and few SLs are under clinical trials for cancer treatment. Evaluation of additional SLs may prove to be valuable as an adjunct or stand alone treatment especially for CRPC. Dehydroleucodine (DhL), a sesquiterpene lactone isolated from Artemisia douglasiana has several pharmacological benefits such as anti-inflammatory, anti-ulcer and anti-oxidant effects. However, the anti-cancer effects of DhL are not well known. In this study, we have evaluated the effects of DhL against castration-sensitive (LNCaP) and CRPC (PC-3) cells in a pre-clinical study. Our cell viability assay results showed that DhL had pronounced inhibition on PC-3 cell proliferation compared to that of LNCaP cells. Therefore, our subsequent studies focussed on elucidating the effects and mechanism of action of DhL using PC-3 CRPC cells. Our investigations showed that in addition to inhibiting the cell proliferation of PC-3 cells, DhL also abrogated the clonogenic potential of PC-3 cells by activating apoptotic markers such as caspase-3 and PARP-1 and cell cycle inhibitors p21 and p27 respectively. Furthermore, our mechanistic study has identified DhL downregulates the expression of NF-kB (p65) in PC-3 cells which may be contributing to the anti-cancer effects of DhL in these cells. Interestingly, our studies also showed that DhL inhibited the osteoclastogenesis mediated by PC-3 in vitro as determined by tartarate-resistant acid phosphatase (TRAP) assay suggesting that DhL may be beneficial in preventing the bone destruction caused by metastatic CRPC. Taken together, our study warrants further investigation of DhL as a promising natural agent for effective treatment and management of CRPC.

Citation Format: Souresh Banerjee, Gnanasekar Munirathinam. Dehydroleucodine: A potential sesquiterpene lactone for targeting castration-resistant prostate cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5484. doi:10.1158/1538-7445.AM2014-5484
Abstract 5488: Everolimus inhibits the proliferation of aromatase inhibitor-resistant breast cancer cells
Authors: Lui Asona , Lewis-Wambi Joan
Published: May 2015

Aromatase inhibitors (AIs) are currently the standard treatment for estrogen receptor positive breast cancer in postmenopausal women. Unfortunately, the majority of patients treated with AIs eventually develop resistance to these drugs. The mechanism by which AI resistance occurs is still not known, however, there is strong evidence that upregulation of the PI3K/Akt/mTOR pathway might play an important role. As such, mTOR inhibition is now under study in clinical trials as a breast cancer treatment. The newest mTOR inhibitor, Everolimus (Afinitor®), has been FDA approved for the treatment of metastatic breast cancer. We have previously reported the development of two AI-resistant breast cancer cell lines (MCF-7:5C and MCF-7:2A) which were clonally derived from parental MCF-7 cells following long term estrogen deprivation. Both MCF-7:5C and MCF-7:2A cells have been shown to overexpress members of the PI3K/Akt/mTOR pathway. In this study, we examined the therapeutic benefits of everolimus in AI-resistant MCF-7:5C and MCF-7:2A cells compared to endocrine sensitive MCF-7 breast cancer cells and normal breast epithelium MCF10A cells. Results from cell viability assay showed that everolimus markedly inhibited the proliferation of endocrine sensitive MCF-7 cells and AI-resistant MCF-7:5C and MCF-7:2A cells in a time-dependent and concentration-dependent manner with IC50s of 30 nM, 40 nM and 10 nM, respectively. Notably, the MCF-7:2A cells were the most sensitive to everolimus which caused a 70% reduction in proliferation at 24 hours whereas in MCF-7 and MCF-7:5C cells only 30% inhibition was observed at the same time point. The inhibitory effect of everolimus was due primarily to G1 arrest and was associated with significant downregulation of phospho-mTOR, phospho-p70S6K, phospho-Akt, GSK3β, cyclin D1 and p21. Colony formation assay in soft agar indicated that AI-resistant MCF-7:5C and MCF-7:2A cells formed significantly more colonies than MCF-7 cells and that treatment with everolimus notably reduced the size and number of colonies for all three cell lines. Finally, we found that exposure of AI-resistant MCF-7:5C and MCF-7:2A cells to a single dose of gamma-irradiation (6 Gy) significantly enhanced the anti-proliferative effect of everolimus on these cells. In summary, these studies showed that everolimus significantly inhibited the proliferation and tumorigenicity of AI-resistant breast cancer cells and that everolimus might be an effective treatment option for patients with AI-resistant breast cancer.

Citation Format: Asona Lui, Joan Lewis-Wambi. Everolimus inhibits the proliferation of aromatase inhibitor-resistant breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5488. doi:10.1158/1538-7445.AM2014-5488
Abstract 5493: Metformin synergizes 5-fluorouracil, epirubicin, and cyclophosphamide (FEC) sensitivity in breast cancer stem cells and non-stem breast cancer cells
Authors: Soo Sian Siu , Ng Char Hong , Malik Rozita Abdul , Teh Yew Ching , Tan Boon Shing , Ho Gwo Fuang , See Mee Hoong , Taib Nur Aishah Mohd , Yip Cheng Har , Teo Soo Hwang , Leong Chee Onn
Published: May 2015

Incorporating cancer stem cells (CSCs)-targeting therapies into current therapies could prevent cancer progression, recurrence and metastasis. An anti-diabetic, AMPK-activating drug, metformin has been shown to kill CSCs and reduces cancer incidence and cancer related death. This study aimed to evaluate the combination treatment of metformin or other AMPK/mTOR-acting drugs with chemotherapy on breast CSCs and non-CSCs in the pre-clinical and clinical settings. We investigated the combination effect of metformin, AICAR, A-769662, or rapamycin with doxorubicin, cisplatin, paclitaxel, or FEC on breast CSCs (mammospheres) and non-CSCs in vitro. The study was extended clinically in a pilot study of ten non-diabetic locally advanced breast cancer patients treated with metformin and neoadjuvant FEC chemotherapy. Nine patients treated with FEC only were identified as historical controls. ESA+/CD44+/CD24-/low (CSCs) population of the tumor samples and tumor response were evaluated. In contrast to other drugs, metformin exhibited higher sensitivity in CSCs compared to attached cell lines. Metformin combined with FEC demonstrated a synergistic effect on breast CSCs and non-CSCs. Patients receiving metformin/FEC neoadjuvant therapy showed a significant reduction in CSCs proportion (P=0.008). Proportion of CSCs after treatment with metformin/FEC was significantly lower compared with the FEC-only neoadjuvant group (P=0.008). Five out of nine patients (56%) receiving metformin/FEC therapy showed a clinical response versus one out of eight (13%) patients in the FEC-only group. In conclusion, metformin synergizes FEC sensitivity in both CSCs and non-CSCs in breast cancer cell lines. Combination treatment of metformin and FEC reduces CSCs in primary tumor from non-diabetic locally advanced breast cancer patients. These results indicate that neoadjuvant metformin/FEC may be a potential treatment option for breast cancer patients and warrants further clinical investigations.

Citation Format: Sian Siu Soo, Char Hong Ng, Rozita Abdul Malik, Yew Ching Teh, Boon Shing Tan, Gwo Fuang Ho, Mee Hoong See, Nur Aishah Mohd Taib, Cheng Har Yip, Soo Hwang Teo, Chee Onn Leong. Metformin synergizes 5-fluorouracil, epirubicin, and cyclophosphamide (FEC) sensitivity in breast cancer stem cells and non-stem breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5493. doi:10.1158/1538-7445.AM2014-5493
Abstract 5496: Mechanisms of anti-tumurogenic activity of the brown seaweed, F. vesiculosus
Authors: Riby Jacques E. , Conde Lucia , Cui Xiangqin , Zhang Jianqing , Skibola Christine F.
Published: May 2015

Introduction. We previously reported significant anti-estrogenic effects related to the consumption of the brown seaweed, F. vesiculosus. The present study aimed to further characterize the mechanisms involved and to investigate other actions of F. vesiculosus that may be biologically relevant.

Methods. Activation of the estrogen receptor was determined using a luciferase reporter assay (CALUX assay) in six breast, ovarian and endometrial cancer cells lines (MCF7, T47D, MDA-MB-231, OVCAR-3 and HEC-1-B) treated with an F. vesiculosus extract. Cell proliferation and apoptosis were determined by the MTT assay and the AnnexinV affinity assay, respectively. Gene expression profiling for 248 genes in pathways including tumor suppression, apoptosis, autophagy, hormonal regulation, cell cycling, proliferation, angiogenesis, inflammation and oxidative stress were analyzed using the nCounter Analysis System (NanoString Technologies, Seattle, WA), and validated by real-time quantitative RT-PCR. A two-way ANOVA model, with cell line effect and treatment dose effect, was fitted to the normalized expression data for each gene. The permutation based F-test was used to identify genes differentially expressed between treatment doses.

Results. In co-treatments with 12.5 pM β-estradiol (EC50), F. vesiculosus reduced ER activity by ∼50% at the 1mg/mL dose, showing a potent ER antagonist effect. All cells showed a progressive decrease in proliferation rates, as measured by the MTT assay over 3 days, with increasing concentrations of the seaweed extract, but the sensitivity of individual cell lines was variable. The two endometrial cell lines were most responsive, with up to a 50% reduction in cell number, whereas the MDA-MB-231 breast cancer cell line was least responsive with a 30% overall reduction. Transcription levels of multiple genes were affected by the treatments in all cell lines, with more notable effects in apoptosis, proliferation, and several receptor-mediated signaling pathways.

Conclusion. Our results provide new insights into the anti-estrogenic activity of F. vesiculosus through direct inhibition of estrogen receptor activation that may be particularly relevant in the pathogenesis and progression of female cancers. We also found that the F. vesiculosus extract reduced cell proliferation, induced apoptosis and up-regulated genes in signaling pathways that have anti-tumorigenic potential.

Citation Format: Jacques E. Riby, Lucia Conde, Xiangqin Cui, Jianqing Zhang, Christine F. Skibola. Mechanisms of anti-tumurogenic activity of the brown seaweed, F. vesiculosus. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5496. doi:10.1158/1538-7445.AM2014-5496
Abstract 5498: Changes in expression of DNA repair genes in human leukemia cells treated with laromustine
Authors: Robinson Kristen N. , Coe Kathryn A. , Owumi Justin E. , Rice Kevin P.
Published: May 2015

The anticancer prodrug laromustine induces cytotoxic DNA damage and has had clinical success against acute myelogenous leukemia and glioblastoma multiforme. The causative DNA damage is principally a G-C interstrand crosslink preceded by 2-chloroethylation of guanine O6 by a subspecies of laromustine generated in situ upon base-catalyzed activation. Another cogenerated electrophile, methylisocyanate, contributes synergistically with the DNA alkylating activity towards cytotoxicity. Given this synergism, DNA repair enzymes are considered likely targets of methylisocyanate, which can carbamoylate amines and sulfhydryls. The inhibition of O6-alkylguanine-DNA alkyltransferase (AGT) and DNA polymerase beta by laroumustine's carbamoylating activity, observed in vitro, may contribute to cytotoxicity. To further investigate the relationship between laromustine and DNA repair, drug-induced changes in the transcription of 88 DNA repair genes were measured in cultured human promyelocytic (HL-60) cells using quantitative real-time reverse transcriptase PCR. Cells were treated with laromustine or vehicle for six hours before harvesting mRNA for analysis. The expression of a subset of the tested genes emerged as significantly different in cells treated with laromustine as compared to control cells. Included among those genes with significantly increased expression were: NTHL1 (17 fold), PARP1 (8 fold), and AGT (5 fold). Included among those genes with significantly decreased expression were: PARP2 (-5 fold) and MSH6 (-74 fold). Increased expression of NTHL1, which encodes for an N-glycosylase that can remove damaged guanine bases, may reduce the effectiveness of laromustine's alkylation of guanine O6. A strong negative correlation between the level of AGT activity in patient samples and the efficacy of laromustine has already been established. Some of the gene products identified in this study, such as NTHL1, may emerge as possible cotherapeutic targets or markers for clinical screening.

Citation Format: Kristen N. Robinson, Kathryn A. Coe, Justin E. Owumi, Kevin P. Rice. Changes in expression of DNA repair genes in human leukemia cells treated with laromustine. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5498. doi:10.1158/1538-7445.AM2014-5498
Abstract 5501: Combined effects of docetaxel-magnetic nanoparticles with different surface modifications on prostate cancer cells
Authors: Furuta Nao , Yamaguchi Sou , Iwasaki Ayumi , Okamoto Daiki , Sato Akiko , Endo Yoshihiro , Kurioka Daisuke , Nittami Tadashi , Ishiguro Hitoshi , Uemura Hiroji , Kunota Yoshinobu , Watanabe Masatoshi
Published: May 2015

Docetaxel-based chemotherapy prolongs life and relieves symptoms in patients with castration resistant prostate cancer. However, this needs to be improved because of limitations by lack of specificity, systemic toxicity, and progression of docetaxel-resistance. Nanotechnology has served a new role in medical sciences by a variety of nanotechnology platforms, leading to theranostics. Among these platforms, Fe3O4 magnetic nanoparticles (MgNPs) have potential applications in drug delivery, cancer diagnosis and hyperthermia. We have already shown that MgNPs would modify the effect of chemotherapy in prostate cancer cells based on the observations that MgNPs increased reactive oxygen species (ROS) production and induced oxidative DNA damage in prostate cancer cell lines. Combined treatment of docetaxel and MgNPs has also shown to suppress nuclear transcription factor kappa B expression in DU145 cells. In this study, we analyzed the combined effects of docetaxel-MgNPs with different surface modifications on a prostate cancer cell line, DU145 and their mechanisms. The combination treatment of docetaxel and carboxylic acid-modified MgNPs (MgNPs-COOH) more effectively inhibited cancer cell growth and induced apoptosis compared with docetaxel-MgNPs combination. While MgNPs produced ROS in a dose-dependent manner and inhibited cancer cell growth slightly, MgNPs-COOH did exert no ROS production, however cell membrane damage in a dose-dependent manner. In addition, MgNPs-COOH showed the involvement of the endoplasmic reticulum (ER) stress. These results suggest that MgNPs-COOH may induce different responses compared with MgNPs, and result in favorable development of current chemotherapy for the advanced disease and leading to new theranostics.

Citation Format: Nao Furuta, Sou Yamaguchi, Ayumi Iwasaki, Daiki Okamoto, Akiko Sato, Yoshihiro Endo, Daisuke Kurioka, Tadashi Nittami, Hitoshi Ishiguro, Hiroji Uemura, Yoshinobu Kunota, Masatoshi Watanabe. Combined effects of docetaxel-magnetic nanoparticles with different surface modifications on prostate cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5501. doi:10.1158/1538-7445.AM2014-5501
Abstract 5508: Bromodomain and hegdehog pathway targets in small cell lung cancer
Authors: Kaur Gurmeet , Reinhart Russell A. , Monks Anne , Evans David , Morris Joel , Teicher Beverly A.
Published: May 2015

Small cell lung cancer (SCLC) is an extremely aggressive cancer that frequently recurs after conventional cytotoxic chemotherapy. SCLC is a neuroendocrine lung malignancy for which there is no effective treatment that affects >200,000 people world-wide every year with a very high mortality rate (<5% of patients survive five years). SCLC cells are, indeed, small with limited cytoplasm surrounding the nuclei. The cells tend to grow as floating clusters or spheroids which are often difficult to disaggregate. Twenty-four human SCLC lines were assessed for response to bromodomain inhibitors and hedgehog pathway inhibitors. Gene expression determined from Affymetrix Exon ST1 arrays and protein expression determined by western blotting confirmed that 6 SCLC lines expressed high levels of c-Myc, 5 lines expressed high levels of L-Myc and 3 lines expressed high levels of n-Myc. The c-Myc over-expressing lines expressed very low levels of ASCL1 and high levels of SMO. The L-Myc over-expressing lines expressed high ASCL1 and moderate SMO, and the n-Myc over-expressing lines had variable expression of ASCL1 and moderate expression of hedgehog pathway genes. Gene expression data is being correlated with the protein expression in 24 human SCLC cell lines using western blot analysis. Nine point concentration response experiments were performed with the bromodomain inhibitors JQ1 and I-BET-15. In general, the Myc over-expressing SCLC lines were more sensitive to the Bromodomain inhibitors than were the lines without Myc amplification. At the IC50 concentrations, the c-MYC over-expressing lines were >-4-fold more sensitive to JQ1 than the lines without Myc amplification while the L-Myc over-expressing lines were >-3-fold more sensitive and the n-Myc over-expressing lines were >-9-fold more sensitive to JQ1 than the lines without Myc amplification. Concentration response experiments with the same 24 SCLC lines were carried out with the Hedgehog pathway inhibitors HPI1, SEN-450, LDE225 (erismodegib; clinical Cmax = 9 uM) and GDC0049 (vismodegib; clinical Cmax = 34 uM). The SCLC lines which over-express Myc were more sensitive to the 4 hedgehog pathway inhibitors than were the lines without Myc amplification. Although the 6 c-Myc over-expressing lines had higher levels of SMO gene expression than the other SCLC lines, they were not different in sensitivity to the SMO inhibitors than the other Myc over-expressing lines. Further studies of SCLC lines response to investigational agents are underway.

Citation Format: Gurmeet Kaur, Russell A. Reinhart, Anne Monks, David Evans, Joel Morris, Beverly A. Teicher. Bromodomain and hegdehog pathway targets in small cell lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5508. doi:10.1158/1538-7445.AM2014-5508
Abstract 5513: Targeting brain tumor initiating cells in atypical teratoid/rhabdoid tumors: Aldehyde dehydrogenase inhibition with disulfiram
Authors: Choi Seung A. , Choi Jung Won , Wang Kyu-Chang , Phi Ji Hoon , Lee Ji Yeoun , Kim Yong Hwy , Kim Young-Hoon , Park Sung-Hye , Kim Seung-Ki
Published: May 2015

Atypical teratoid/rhabdoid tumors (AT/RT) are one of the most malignant pediatric brain tumors with a dismal prognosis. Cells with high aldehyde dehydrogenase (ALDH) activity from brain tumors have a number of characteristics that are expected of brain tumor initiating cells (BTICs). This study aimed to evaluate the therapeutic potential of ALDH inhibition using disulfiram (DSF) against BTICs from AT/RT.

Primary cultured BTICs from AT/RT were stained with Aldefluor and isolated by fluorescence activated cell sorting. Therapeutic effect of DSF against BTICs from AT/RT was confirmed using in vitro and in vivo studies.

AT/RT showed high expression of ALDH. DSF significantly inhibited ALDH enzyme activity of AT/RT cells. DSF decreased self-renewal ability, cell viability, proliferation potential and induced apoptosis and cell cycle arrest on ALDH+ AT/RT cells. DSF showed more potent cytotoxic effect to ALDH+ AT/RT cells compared to standard anti-cancer agents including ifosfamide, carboplatin and etoposide. Importantly, DSF reduced metabolite (metabolism?) of ALDH+ AT/RT cells by increasing NAD+ ratio and regulating SIRT1, NF-κB, Lin28A/B and miRNA let-7g. Notably, treatment with DSF did not have considerable effect on the normal neural stem cells and fibroblasts. Animals in the DSF-treated group demonstrated a significant survival benefit (105 days of median survival in the DSF-treated group versus 91 days in the control group, p = 0.0219).

Our study demonstrated the therapeutic potential of DSF against BTICs from AT/RT and suggested the possibility of ALDH inhibition for clinical application.

Note: This abstract was not presented at the meeting.

Citation Format: Seung Ah Choi, Jung Won Choi, Kyu-Chang Wang, Ji Hoon Phi, Ji Yeoun Lee, Yong Hwy Kim, Young-Hoon Kim, Sung-Hye Park, Seung-Ki Kim. Targeting brain tumor initiating cells in atypical teratoid/rhabdoid tumors: Aldehyde dehydrogenase inhibition with disulfiram. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5513. doi:10.1158/1538-7445.AM2014-5513
Abstract 5570: Laminin-5 gamma-2 (LAMC2) is highly expressed in anaplastic thyroid carcinoma and is associated with tumor progression, migration and invasion by modulating signaling of EGFR
Authors: Garg Manoj , Kanojia Deepika , Okamoto Ryoko , Madan Vikas , Chien Wenwen , Sampath Abhishek , Ding Ling-Wen , Xuan Meng , Said Jonathan W , Doan Ngan , Liu Li-Zhen , Yang Henry , Gery Sigal , Braunstein Gleen D , Koeffler H.Phillip
Published: May 2015

Context: Anaplastic thyroid carcinoma (ATC) is an aggressive malignancy having no effective treatment. Laminin subunit gamma-2 (LAMC2) is an epithelial basement membrane protein involved in cell migration and tumour invasion and might represent an ideal target for the development of novel therapeutic approaches for ATC.

Objective: Study the role of LAMC2 in ATC tumorigenesis.

Design: LAMC2 expression was evaluated by RT-PCR, western blotting and immunohistochemistry in tumor specimens, adjacent non-cancerous tissues and cell lines. shRNA approach was used to investigate the effect of LAMC2 knockdown on tumorigenesis of ATC.

Results: LAMC2 was highly expressed in ATC samples and cell lines compared to normal thyroid tissues. Silencing LAMC2 by shRNA in ATC cells moderately inhibited cell growth in liquid culture and dramatically decreased growth in soft agar and in xenografts growing in immunodeficient mice. Silencing LAMC2 caused cell cycle arrest and significantly suppressed migration, invasion and wound healing of ATC cells. Rescue experiments by overexpressing LAMC2 in LAMC2 knockdown cells, reversed the inhibitory effects as shown by increased cell proliferation and colony formation. Microarray data demonstrated that LAMC2 shRNA significantly altered expression of genes associated with migration, invasion, proliferation and survival. Immunoprecipitation and co-localization experiments showed that LAMC2 bound to EGFR in ATC cells. Silencing LAMC2 partially blocked EGF-mediated activation of EGFR and its downstream pathway. Interestingly, cetuximab (EGFR blocking antibody) or EGFR siRNA additively enhanced the anti-proliferative activity of the LAMC2 knockdown ATC cells compared to control cells.

Conclusions: To our knowledge, this is the first report investigating the effect of LAMC2 on cell growth, cell cycle, migration, invasion and EGFR signaling in ATC cells, suggesting that LAMC2 may be a potential therapeutic target for treatment of ATC.

Citation Format: Manoj Garg, Deepika Kanojia, Ryoko Okamoto, Vikas Madan, Wenwen Chien, Abhishek Sampath, Ling-Wen Ding, Meng Xuan, Jonathan W Said, Ngan Doan, Li-Zhen Liu, Henry Yang, Sigal Gery, Gleen D Braunstein, H.Phillip Koeffler. Laminin-5 gamma-2 (LAMC2) is highly expressed in anaplastic thyroid carcinoma and is associated with tumor progression, migration and invasion by modulating signaling of EGFR. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5570. doi:10.1158/1538-7445.AM2014-5570
Abstract 5577: ERG enhances prostate cancer growth by upregulating neurotransmitter receptors
Authors: On Seungtae
Published: May 2015

Almost 50% of prostate cancer (PCa) cases exhibit a gene fusion between TMPRSS2 and the ETS transcription factor ERG. ERG is suspected to promote the acceleration and progression of prostate cancer. However, the mechanisms whereby ERG exerts its affects growth and development of the prostate cancer cell is are poorly understood. We aimed to identify and characterize ERG-related changes using a prostate tumor cell as a model. We profiled the transcription and metabolomics of cell lines induced to express ERG, and used RT-PCR, calcium influx, proliferation and phosphorylation assays to test our in silico observations. Genome-wide gene expression and metabolite profiling revealed a significantly increased representation of neuronal receptors and metabolites in the ERG+ cells. Specifically, ERG+ cells overexpressed several nicotinic, adrenergic and glutamate receptors. Out of all three receptors, nicotinic receptors were predominently upregulated compared to others. To test the function of these receptors, cells expressing ERG were treated with neuronal receptor agonists nicotin, epinephrine and glutamate. Interestingly, ERG+ cells responded with increased calcium influx, and phosphorylation of pAKT and GSK3b. Nicotine increased cellular growth in ERG+ cells, but had no effect on the ERG- cells. Similar expression of these receptors was found in human PCa samples. Furtheremore, our analysis using the EDRN tissue bank identified a positive correlation between smoking and tumor size among TMRPSS2:ERG expressing PCa patients. Collectively, our findings suggest a correlation between neurotransmitter receptors and cellular proliferation of ERG-expressing Pca, and identify GSK3b and pAKT as the possible underlying signaling mediators.

Citation Format: Seungtae On. ERG enhances prostate cancer growth by upregulating neurotransmitter receptors. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5577. doi:10.1158/1538-7445.AM2014-5577
Abstract 623: BIG3-PHB2 interaction is a key therapeutic target in luminal-type of breast cancer
Authors: Katagiri Toyomasa , Yoshimaru Tesuro , Komatsu Masato , Matsuo Taisuke
Published: May 2015

More than 70% of primary breast tumors are estrogen receptor alpha (ERα)-positive, and the interactions between estrogen (E2) and ERα dramatically enhance the proliferative and metastatic activity of breast tumor cells. The selective estrogen receptor modulator tamoxifen directly inhibits E2 and ERα interactions and is a standard treatment offered to patients with ERα-positive breast cancer. The acquisition of endocrine resistance is a common obstacle in endocrine therapy for ERα-positive breast tumors. Therefore, identifying the factors and pathways responsible for resistance and defining ways to overcome it represent important therapeutic challenges in breast cancer research. Prohibitin 2 (PHB2) is known to function as a co-repressor of ERα because it regulates ERα transcriptional activity via its direct binding to ERα. However, it remains unclear how endogenous PHB2 is inactivated in ERα-positive breast cancer cells, despite its abundant expression and the lack of genomic mutations or methylations in breast cancer clinical specimens or cell lines. Here we report that brefeldin A-inhibited guanine nucleotide-exchange protein 3 (BIG3) protein interacts PP1α, and dephosphorylates the E2-dependent phosphorylation of PHB2, which is indispensable for its tumor suppressive ability, thereby causing an apparent “loss-of-function” of PHB2 protein, resulting in the constitutive activation of ERα signaling pathways. These findings demonstrate for the first time the novel mechanism for the inactivation of tumor suppressor protein. From a therapeutic perspective, intrinsic PHB2 released from BIG3 by the cell-permeable peptide inhibitor directly binds to both nuclear- and membrane-associated ERα, which leads to the inhibition of multiple ERα-signaling pathways, and the growth of ERα-positive breast cancer cells both in vitro and in vivo. More importantly, this peptide inhibitor treatment suppressed tamoxifen resistance and enhanced tamoxifen responsiveness in ERα-positive breast cancer cells. These findings mark the first step toward uncovering a new E2/ ERα signaling network in breast cancer and shed light on novel therapeutic strategies utilizing PHB2 protein functions for E2/ ERα-positive breast cancer.

Citation Format: Toyomasa Katagiri, Tesuro Yoshimaru, Masato Komatsu, Taisuke Matsuo. BIG3-PHB2 interaction is a key therapeutic target in luminal-type of breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 623. doi:10.1158/1538-7445.AM2014-623
Abstract 633: Inhibition of TGFβ as a strategy to convert the irradiated tumor into in situ individualized vaccine
Authors: Vanpouille-Box Claire I. , Diamond Julie M. , Zavadil Jiri , Babb James , Schaue Dörthe , Barcellos-Hoff Mary Helen , McBride William H. , Formenti Silvia C. , Demaria Sandra
Published: May 2015

Accumulating data support the concept that ionizing radiation therapy (RT) has the potential to convert the tumor into an in situ, individualized vaccine; however this potential is rarely realized by RT alone. Transforming growth factor β (TGFβ) is an immunosuppressive cytokine that is activated by RT and inhibits the antigen-presenting function of dendritic cells and the differentiation of effector CD8+ T cells. Here we tested the hypothesis that TGFβ hinders the ability of RT to promote anti-tumor immunity. Development of tumor-specific immunity was examined in two pre-clinical models of metastatic breast cancer and analyzed in patients with metastatic breast cancer treated with local radiotherapy and the TGFβ-neutralizing antibody Fresolimumab.

Mice bearing established 4T1 and TSA mouse mammary carcinomas treated with pan-isoform specific TGFβ neutralizing antibody, 1D11, showed significantly improved control of the irradiated tumor and non-irradiated metastases, but no effect in the absence of RT. Notably, whole tumor transcriptional analysis demonstrated the selective upregulation of genes associated with immune-mediated rejection only in tumors of mice treated with RT+TGFβ blockade. Mice treated with RT+TGFβ blockade exhibited cross-priming of CD8+ T cells producing IFNγ in response to three tumor-specific antigens in tumor-draining lymph nodes, which was not evident for single modality treatment. Likewise, HLA-A2.1+ metastatic breast cancer patients (n=8) enrolled in NCT01401062 trial of local RT and fresolimumab were examined for CD8+ T cells specific for the tumor antigen survivin by tetramer staining. Three patients developed increased frequencies of survivin-specific CD8+ T cells in the blood during treatment, while two patients negative at baseline became positive.

Analysis of the immune infiltrate in mouse tumors showed a significant increase in CD4+ and CD8+ T cells only in mice treated with the combination of RT+TGFβ blockade. Depletion of CD4+ or CD8+ T cells abrogated the therapeutic benefit of RT+TGFβ blockade.

These data identify TGFβ as a master inhibitor of the ability of RT to generate an in situ tumor vaccine, which supports testing inhibition of TGFβ during radiotherapy to promote therapeutically effective anti-tumor immunity.

Supported by DOD BCRP Multi-Team Award BC100481.

Citation Format: Claire I. Vanpouille-Box, Julie M. Diamond, Jiri Zavadil, James Babb, Dörthe Schaue, Mary Helen Barcellos-Hoff, William H. McBride, Silvia C. Formenti, Sandra Demaria. Inhibition of TGFβ as a strategy to convert the irradiated tumor into in situ individualized vaccine. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 633. doi:10.1158/1538-7445.AM2014-633
Abstract CT207: Pharmacokinetic analysis of the HDAC inhibitor belinostat (PXD-101) and metabolites in patients with hepatic dysfunction
Authors: Kiesel Brian , Parise Robert , Lin Yan , Allen Deborah , Reddy Guru , Chawla Shanta , Piekarz Richard , Ivy Percy , Kumar Shivaani , Beumer Jan H.
Published: May 2015

Introduction: Histone deacetylases (HDAC) are frequently deregulated in human cancers and their inhibition allows re-expression of silenced genes. Belinostat is an HDAC inhibitor with in vitro and in vivo activity in multiple malignancies, currently in phase II trials. We report the pharmacokinetics of belinostat and metabolites in patients enrolled in a phase I liver dysfunction trial currently being conducted and led by the NCI.

Methods: Patients enrolled into the study were assigned to varying cohorts depending on their level of hepatic dysfunction (normal=N, mild=H1, moderate=H2, and severe=H3). All patients were given a 30 minute infusion at 400 mg/m2 on cycle 1 day -7. Heparinized plasma samples were collected prior to infusion, 15 and 25 min after start, and 5, 10, 15, 30, 60, 90, 120, 240, 360, 480 and 1440 minutes after infusion. Patients from the NCIDTC had samples collected and these were quantitated by a previously validated assay for belinostat, belinostat-glucuronide, methyl-belinostat, M21, M24, and M26. Pharmacokinetic parameters were derived non-compartmentally with PK Solutions. Metabolic ratios were calculated as a measure of metabolic fate.

Results: 15 patients (N=2, H1=10, H2=2, H3=1) had useable pharmacokinetic data. Observed belinostat Cmax (N=21.1±4.9, H1=55.8±78.0, H2=23.0±7.2, H3=23.1 µg/mL) and belinostat AUC0-inf (N=806±294, H1=1308±996, H2=702±82, H3=780 µg/mL•min) did not reveal any trends with dysfunction cohort. Metabolic AUC0-inf ratios of belinostat to the various metabolites also did not appear to change with dysfunction cohort.

Conclusion: Liver function does not appear to affect the pharmacokinetics or metabolic fate of belinostat. Analysis of additional subjects is ongoing. The results of this study will facilitate optimal dosing for patients with liver dysfunction.

Citation Format: Brian Kiesel, Robert Parise, Yan Lin, Deborah Allen, Guru Reddy, Shanta Chawla, Richard Piekarz, Percy Ivy, Shivaani Kumar, Jan H. Beumer. Pharmacokinetic analysis of the HDAC inhibitor belinostat (PXD-101) and metabolites in patients with hepatic dysfunction. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr CT207. doi:10.1158/1538-7445.AM2014-CT207
Abstract CT304: Anti-prostate-specific membrane antigen (PSMA) monoclonal antibody J591 plus low-dose interleukin-2 (IL-2) in patients with recurrent prostate cancer (PC)
Authors: Khagi Yulian , Kaur Gurveen , Christos Paul , Akhtar Naveed H. , Nanus David M. , Bander Neil H. , Tagawa Scott T.
Published: May 2015

Purpose

J591 is a deimmunized monoclonal antibody that recognizes the extracellular domain of prostate specific membrane antigen and was engineered to induce antibody-dependent cellular cytotoxicity (ADCC). Low dose IL-2 may enhance ADCC by the clonal expansion of natural killer (NK) cells. Immunotherapy may result in survival benefits independent of immediate response. This study was designed to evaluate the efficacy of J591 plus low-dose IL-2 in men with recurrent PC.

Experimental Design

Men with non-castrate PSA relapse or progressive metastatic castration-resistant PC (mCRPC) received low-dose subcutaneous IL-2 (1.2 x 106 IU/m2/day) daily for 8 weeks with weekly intravenous infusions of J591 (25 mg/m2) on weeks 4-6 (considered 1 cycle). A maximum of 3 cycles of therapy was delivered. Flow cytometry was used to assess NK cell fraction and PSA changes and survival were assessed.

Results

Seventeen men were treated between 2001-03 with at least 1 cycle (11 PSA relapse, 6 mCRPC) with 1 mCRPC patient invaluable for PSA response due to a protocol violation (9 received 2 cycles, 2 received 3 cycles). Toxicity was mild, mainly limited to fatigue and injection site reactions. PSA declined following therapy in 7 of 16 evaluable men (2 of 5 mCRPC). Flow cytometry revealed an average increase in absolute NK cell count of 107% at week 4 and 117% at the end of cycle 1. NK cell percent change had an inverse relationship with PSA (2-tailed Pearson correlation coefficient r = -0.46; P= 0.13). The actual vs. predicted survival for 5 of the 6 men with mCRPC disease was greater than predicted by the Halabi nomogram (Spearman correlation analysis r=0.29; P=0.57, i.e. nomogram did not predict survival).

Conclusions

The combination of J591 with low-dose IL-2 was well tolerated in patients with biochemical relapse and mCRPC. In addition, combination therapy expanded NK cell fraction which correlated with PSA decline. Interestingly, long term follow up reveals that 83% of the mCRPC group lived significantly longer than predicted, mostly in an era prior to the approval of life-prolonging therapy. These data support further testing of the hypothesis that PSMA-directed immunotherapy influences outcome in men with advanced PC.

Citation Format: Yulian Khagi, Gurveen Kaur, Paul Christos, Naveed H. Akhtar, David M. Nanus, Neil H. Bander, Scott T. Tagawa. Anti-prostate-specific membrane antigen (PSMA) monoclonal antibody J591 plus low-dose interleukin-2 (IL-2) in patients with recurrent prostate cancer (PC). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr CT304. doi:10.1158/1538-7445.AM2014-CT304
Abstract CT414: Efficient induction of cellular and humoral immune responses by heterologous prime-boost therapeutic vaccination, involving plasmid DNA and adenoviral vector, in subjects with HER2-expressing breast cancer: Results from a phase Ib study
Authors: KIM SUNGBAE , Jung KyungHae , Ahn JinHee , Kim Jeongeun
Published: May 2015

A phase I clinical trial was conducted to assess safety, tolerability and preliminary efficacy of a heterologous prime-boost strategy, involving a plasmid DNA (pHM-GM-CSF, expressing truncated HER2 and GM-CSF as a bicistronic message) and an adenoviral vector (Ad-HM, containing the same modified HER2 sequence only), in subjects with stage III-IV metastatic breast cancer expressing HER2 (1+∼3+ by immunohistochemistry). Nine eligible subjects were divided into three cohorts based on three different DNA doses (2, 4 and 8 mg) of pHM-GM-CSF, which were intramuscularly injected three times on weeks 0, 2, and 4 (i.e. 6, 12, and 24mg in total), followed by a single injection of Ad-HM (3x109 viral particle) on week 6. Relevant parameters were measured during the 6-month follow-up period. Seven minor grade 1 toxicities were found in four of nine patients, while no drug-related serious adverse event was reported. HER2-specific cell-mediated or humoral immunities were produced in all (100 %) or three patients (33 %), respectively. One patient showed a partial response, and seven subjects had stable diseases. No clear correlation was observed between DNA dosages and induction of immunogenicity and clinical tumor response. Our data showed that intramuscular injection of pHM-GM-CSF 24mg and Ad-HM 3x109 VP were well tolerated and safe. To our knowledge, this is the first clinical study demonstrating an efficient induction of HER2-specific cellular and humoral responses in patients with metastatic breast cancer expressing HER2.

Citation Format: SUNGBAE KIM, KyungHae Jung, JinHee Ahn, Jeongeun Kim. Efficient induction of cellular and humoral immune responses by heterologous prime-boost therapeutic vaccination, involving plasmid DNA and adenoviral vector, in subjects with HER2-expressing breast cancer: Results from a phase Ib study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr CT414. doi:10.1158/1538-7445.AM2014-CT414
Abstract DDT02-03: Discovery of GDC-0994, a potent and selective ERK1/2 inhibitor in early clinical development
Authors: Robarge Kirk , Schwarz Jacob , Blake Jim , Burkard Michael , Chan Jocelyn , Chen Huifen , Chou Kang-Jye , Diaz Dolores , Gaudino John , Gould Stephen , Grina Jonas , Linghu Xin , Liu Lichuan , Martinson Matthew , Moreno David A. , Orr Christine , Pacheco Patricia , Qin Ann , Rasor Kevin , Ren Li , Shahidi-Latham Sheerin , Stults Jeffrey , Sullivan Francis , Wang Weiru , Yin Peter , Zhou Aihe , Belvin Marcia , Merchant Mark , Moffat John G.
Published: May 2015

The extracellular-signal-regulated kinases (ERK1 and ERK2) represent an essential node within the RAS/RAF/MEK/ERK signaling cascade that commonly is activated by oncogenic mutations in BRAF or RAS or by upstream oncogenic signaling, such as receptor tyrosine kinase (RTK) activation. While targeting upstream nodes with RAF and MEK inhibitors has proven effective clinically, resistance frequently develops through reactivation of the pathway. Simultaneous targeting of multiple nodes in the pathway, such as MEK and ERK, offers the prospect of enhanced efficacy as well as reduced potential for acquired resistance. Here, we present the discovery and characterization of GDC-0994, an orally bioavailable, small molecule inhibitor of ERK kinase activity. GDC-0994 is highly selective for ERK1 and ERK2, with biochemical potency of 1.1 nM and 0.3 nM, respectively. Daily, oral dosing of GDC-0994 results in significant single-agent activity in multiple in vivo cancer models, including KRAS-mutant and BRAF-mutant human xenograft tumors in mice. PD biomarker inhibition of phospho-p90RSK in these tumors correlates with potency in vitro and in vivo. In contrast to other published ERK inhibitors, GDC-0994 neither increases nor decreases phospho-ERK, suggesting that different ERK inhibitors have alternative mechanisms of action with respect to feedback signaling. Furthermore, we demonstrate a novel approach for targeting the oncogenic signaling through the RAS pathway by combining ERK and MEK inhibitors. GDC-0994 is currently in Phase I clinical development.

Citation Format: Kirk Robarge, Jacob Schwarz, Jim Blake, Michael Burkard, Jocelyn Chan, Huifen Chen, Kang-Jye Chou, Dolores Diaz, John Gaudino, Stephen Gould, Jonas Grina, Xin Linghu, Lichuan Liu, Matthew Martinson, David A. Moreno, Christine Orr, Patricia Pacheco, Ann Qin, Kevin Rasor, Li Ren, Sheerin Shahidi-Latham, Jeffrey Stults, Francis Sullivan, Weiru Wang, Peter Yin, Aihe Zhou, Marcia Belvin, Mark Merchant, John G. Moffat. Discovery of GDC-0994, a potent and selective ERK1/2 inhibitor in early clinical development. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr DDT02-03. doi:10.1158/1538-7445.AM2014-DDT02-03
Abstract LB-101: The antiandrogen drug dutasteride sensitizes triple negative breast cancer cells to chemotherapy via HIF-1α / VEGF-signaling
Authors: Wahlde Marie-Kristin von , Huelsewig Carolin , Ruckert Christian , Götte Martin , Kiesel Ludwig , Liedtke Cornelia , Bernemann Christof
Published: May 2015

Background: Triple negative breast cancer is characterized by a lack of expression of both estrogen and progesterone receptor as well as lack of amplification of HER2. Patients with triple negative breast cancer carry an unfavorable prognosis compared to other breast cancer subtypes given that endocrine or HER-2 targeted therapies are not effective, rendering chemotherapy the sole effective treatment option to date.

In a previous work by Liedtke et al. ((Liedtke et al., Cancer Res 2009) we generated a list of genes, which showed higher expression in triple negative breast cancer and, in addition, are known to encode targets for known non-oncologic drugs. These gene products might represent targets for future therapies of triple negative breast cancer.

Results: We could identify SRD5A1, which encodes the type-1 isoform of the steroid-5-alpha-reductase, showing a higher expression in triple negative breast cancer both in vivo and in vitro. Dutasteride is a dual blocker of both the type-1 and type-2 isoform of SRD5A1 and is indicated in the treatment of benign prostate hyperplasia. Treatment of triple negative breast cancer cell lines with dutasteride was associated with a dose-dependent decrease in cell viability, altered protein expression of VEGF and HIF-1α and increased chemosensitivity.

Conclusion: Our results demonstrate that firstly, using differential gene expression analysis in clinically relevant breast cancer subtypes, potential new drug targets can be generated. Secondly, we identified the SRD5A1-corresponding anti androgenic drug dutasteride as a combinatorial therapeutic option besides standard chemotherapy in highly aggressive triple negative breast cancer.

Citation Format: Marie-Kristin von Wahlde, Carolin Huelsewig, Christian Ruckert, Martin Götte, Ludwig Kiesel, Cornelia Liedtke, Christof Bernemann. The antiandrogen drug dutasteride sensitizes triple negative breast cancer cells to chemotherapy via HIF-1α / VEGF-signaling. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-101. doi:10.1158/1538-7445.AM2014-LB-101