bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract LB-196: Preventing breast cancer metastases with an anti-angiogenic and anticancer RGD-bearing nanomedicine
Authors: Eldar-Boock Anat , Ben-Shushan Dikla , Sanchis Joaquin , Lupu Ruth , Vicent Maria J. , Satchi-Fainaro Ronit
Published: May 2015

Overcoming drug resistance, emerging either on recurring cancer or metastasis, is a major challenge of cancer treatments. The combination of anti-angiogenic agents with chemotherapeutic ones offers a promising therapeutic approach. Such combination can be achieved exploiting the multivalency of polymer therapeutics. We have recently showed that polymer conjugation of paclitaxel (PTX), a potent cytotoxic and anti-angiogenic drug, improved its pharmacokinetic profile. We hypothesized that actively targeting PTX to αvβ3-integrin, presents an attractive therapeutic strategy for breast cancer. Interestingly, overexpression of αvβ3-integrin, occurring on tumor endothelial and some epithelial cells during tumor growth, invasion, and metastasis, was found to correlate with PTX-resistance of breast cancer cells.

We designed and synthesized a novel polyglutamic acid (PGA)-PTX-E-[c(RGDfK)2] nano-sized conjugate. Polymer conjugation converted PTX to a water-soluble macromolecule, which passively targeted the tumor tissue exploiting the enhanced permeability and retention (EPR) effect. The E-[c(RGDfK)2] was utilized as an additional active targeting moiety to αvβ3 integrin. PGA is enzymatically-degradable by cathepsin B, leading to PTX release. PGA-PTX-E-[c(RGDfK)2] displayed a potent anti-angiogenic activity, determined by several well-established in vitro assays. Preferential tumor accumulation of the RGD-bearing conjugate in orthotopic mammary tumors inoculated in mice, lead to enhanced antitumor efficacy and a marked decrease in toxicity compared with free PTX. We found that metastasis establishment was dependent on αvβ3-integrin expression as determined in vitro and ex vivo. PGA-PTX-E-[c(RGDfK)2] conjugate inhibited metastatic growth in an experimental breast cancer metastases model in mice.

Taken together, inclusion of an active targeting moiety to integrin expressing-cells has the potential to decrease breast cancer metastases establishment by displaying an anti-angiogenic and anticancer activity.

Citation Format: Anat Eldar-Boock, Dikla Ben-Shushan, Joaquin Sanchis, Ruth Lupu, Maria J. Vicent, Ronit Satchi-Fainaro. Preventing breast cancer metastases with an anti-angiogenic and anticancer RGD-bearing nanomedicine. [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-196. doi:10.1158/1538-7445.AM2014-LB-196
Abstract LB-2: TRIM28 is overexpressed in breast cancer and regulates the expression of multiple cancer-associated genes
Authors: Addison Joseph , Koontz Colton , McLaughlin Sarah , Livengood Ryan , Pugacheva Elena , Chen Dongquan , Creighton Chad , Ivanov Alexey V.
Published: May 2015

The transcriptional regulator TRIM28 plays an important role in development, stem cells self-renewal, chromatin organization and DNA damage response. KAP1 is an essential co-repressor for KRAB zinc finger proteins (KRAB-ZNFs). Though KRAB-ZNFs represent the largest family of human transcription factors, their biological functions are largely unknown. We showed that KAP1 and certain KRAB-ZNFs were overexpressed in breast tumors and breast cancer cell lines at both mRNA and protein levels. More significantly, an active SUMOylated form of KAP1 was markedly increased in breast cancer cells. KAP1 depletion in several breast cancer cell lines slowed cell proliferation and inhibited primary tumor growth and metastasis of MDA-MB-231LN xenografts, while KAP1 overexpression conversely stimulated cell proliferation and tumor growth. KAP1 knockdown led to down-regulation of PTGS2/COX2, EREG, CD44, MMP1, MMP2 and ID transcription factors, previously implicated in cancer progression and metastasis. These results indicate that KAP1 and KRAB-ZNFs are up-regulated in breast cancer cells and contribute to increased cell proliferation, tumor growth and metastasis.

Citation Format: Joseph Addison, Colton Koontz, Sarah McLaughlin, Ryan Livengood, Elena Pugacheva, Dongquan Chen, Chad Creighton, Alexey V. Ivanov. TRIM28 is overexpressed in breast cancer and regulates the expression of multiple cancer-associated genes. [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-2. doi:10.1158/1538-7445.AM2014-LB-2
Abstract LB-200: Potent antitumor activity of MLN0128, an investigational selective mTORC1/2 kinase inhibitor, in preclinical models of rhabdomyosarcoma
Authors: Slotkin Emily , Patwardhan Parag , Deraje Shyamprasad Vasudeva , Schwartz Gary , William Tap
Published: May 2015

Phosphatidylinositol 3-kinase (PI3K)-AKT-mammalian target of rapamycin (mTOR) axis regulates growth and homeostasis, and is often dysregulated in rhabdomyosarcoma. Agents that target mammalian target of rapamycin complex 1 (mTORC1), one of the two multi-protein complexes comprising the serine-threonine kinase mTOR, have been disappointing in clinical trials, and novel therapeutics are urgently needed to treat patients with relapsed, refractory, or metastatic alveolar (ARMS) and embryonal (ERMS) rhabdomyosarcoma. It is hypothesized that modest clinical results with mTORC1 only inhibitors may be attributed to the lack of inhibition of the second mTOR complex, mTORC2, and its downstream effectors, as well as release of mTOR-mediated negative feedback of the pathway that leads to activation of receptor tyrosine kinases and feedback activation of AKT. In the present preclinical study, MLN0128, a selective and highly potent inhibitor of both mTORC1 and mTORC2, was tested for its antitumor activity in vitro and in a mouse xenograft model. Data suggest that the anti-proliferative effect of MLN-0128 was superior to rapamycin, a selective mTORC1 inhibitor, in a broad panel of ERMS and ARMS cell lines where it was found to be highly effective at low concentrations from 5 to 175 nanomolar. Western immunoblot analysis of treated cells showed inhibition of phosphorylation of mTORC1 and mTORC2 targets including phosphorylated S6 ribosomal protein (pS6), phospho-p70-S6K, phospho-AKT-S473, phospho-AKT-T308, and phospho-4E-BP1. Apoptosis in both ERMS and ARMS cell lines was confirmed by the presence of cleaved poly ADP ribose. Additionally, MLN0128 was found to have superior anti-tumor effect in a xenograft model of rhabdomyosarcoma without significant toxicity when compared with rapamycin. These pre-clinical studies support further research of MLN0128 as a potential therapeutic approach for patients with ARMS and ERMS.

Citation Format: Emily Slotkin, Parag Patwardhan, Shyamprasad Vasudeva Deraje, Gary Schwartz, Tap William. Potent antitumor activity of MLN0128, an investigational selective mTORC1/2 kinase inhibitor, in preclinical models of rhabdomyosarcoma. [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-200. doi:10.1158/1538-7445.AM2014-LB-200
Abstract LB-208: Targeting resistance pathways in BRAF-mutant pediatric gliomas
Authors: Yao Tsun-Wen (Sheena) , Yoshida Yasuyuki , Zhang Jie , Ozawa Tomoko , James David , Nicolaides Theodore
Published: May 2015

Mutational activation of BRAF is a common finding in pediatric gliomas. As many as 14% of pediatric high grade glioma and up to 66% of certain low grade pediatric glioma subtypes contain the BRAFV600E mutation. Small molecule inhibitors that selectively target BRAFV600E are FDA approved for melanoma and have shown significant efficacy in treating BRAFV600E glioma in pre-clinical trials. Despite showing initial efficacy, drug resistance significantly limits the use of BRAFV600E inhibitors in clinical settings. Here, we identified the molecular mechanisms of BRAFV600E inhibitor resistance in glioma and also provide strategies to over come drug resistance.

We have generated multiple BRAFV600E inhibitor resistant glioma cell lines and murine models to study the mechanisms of drug resistance in glioma. The BRAFV600E inhibitor resistant AM38 and DBTRG-05MG cells are insensitive to BRAF inhibitor induced MAP kinase inhibition, reduced cell viability and cell cycle arrest. Also, the BRAFV600E inhibitor resistant glioma xenografts do not respond to drug induced suppression of tumor growth, resulting in poor animal survival. By phospho-receptor tyrosine kinase array and gene expression array, we found that certain receptor tyrosine kinases, including EGF and Axl receptors, and pro-survival pathways such as Wnt signaling, are hyperactivated in BRAFV600E inhibitor resistant gliomas. We further showed that pharmacological and genetic inhibition of those pathways significantly reduces the viability of those drug resistant cells.

In conclusion, we have discovered mechanisms of BRAFV600E inhibitor resistance in glioma. We showed that BRAFV600E inhibitor resistant cells acquire drug dependency by upregulating pro-survival pathway, such as Wnt, and hyperactivating receptor tyrosine kinases, including EGFR and Axl, to bypass the insult from the drug. Our data suggests novel therapeutic strategies to BRAFV600E -mutant pediatric glioma in which no effective treatment is available.

Citation Format: Tsun-Wen (Sheena) Yao, Yasuyuki Yoshida, Jie Zhang, Tomoko Ozawa, David James, Theodore Nicolaides. Targeting resistance pathways in BRAF-mutant pediatric gliomas. [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-208. doi:10.1158/1538-7445.AM2014-LB-208
Abstract LB-214: The RAC1 P29S hotspot mutation in melanoma confers resistance to pharmacological inhibition of RAF
Authors: Watson Ian R. , Li Liren , Cabeceiras Peter K. , Mahdavi Mozhdeh , Fang Zhuangna , Stemke-Hale Katherine , Mills Gordon B. , Chin Lynda
Published: May 2015

Following recurrent mutations in BRAF and NRAS, the RAC1 c.85C > T single nucleotide variant encoding P29S amino acid change represents the next most frequently observed hotspot mutation in melanoma. However, the biological and clinical relevance of the RAC1 P29S somatic mutation in approximately 4-9% of patients is not entirely clear. Here, we demonstrate that melanoma cell lines possessing the RAC1 hotspot variant are resistant to RAF inhibitors (dabrafenib and vemurafenib). Enforced expression of RAC1 P29S in sensitive BRAF mutant melanoma cell lines resulted in increased viability and in vivo tumor growth upon treatment with RAF inhibitors compared to controls. Conversely, knockdown of endogenous RAC1 P29S in a melanoma cell line with a co-occurring BRAF V600 mutation increased sensitivity to dabrafenib and vemurafenib. Our results suggest that RAC1 P29S status in melanoma may be an important predictor of RAF inhibitor resistance in patients, and consequently should be evaluated as a predictive biomarker to such therapies in the clinic.

Citation Format: Ian R. Watson, Liren Li, Peter K. Cabeceiras, Mozhdeh Mahdavi, Zhuangna Fang, Katherine Stemke-Hale, Gordon B. Mills, Lynda Chin. The RAC1 P29S hotspot mutation in melanoma confers resistance to pharmacological inhibition of RAF. [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-214. doi:10.1158/1538-7445.AM2014-LB-214
Abstract LB-221: PI3K-independent, Rheb-mediated mTOR activation promotes lapatinib resistance
Authors: Brady Samuel W. , Zhang Jian , Tsai Ming Horng , Yu Dihua
Published: May 2015

Acquired resistance to HER2 kinase inhibitors, such as lapatinib, presents an unmet clinical need among the 20% of breast cancers with HER2 amplification. To identify mechanisms of lapatinib resistance, we generated a lapatinib resistance model by extended exposure of the AU565 HER2-amplified breast cancer cell line to lapatinib (AU565 LapR cell line), which was highly resistant to lapatinib compared to AU565 parental cells. AU565 LapR cells maintained mTORC1 activation (indicated by p-P70 S6K and p-S6) after lapatinib treatment, whereas mTORC1 was completely inhibited in lapatinib-treated parental cells. Moreover, HER2 was inhibited equally well by lapatinib in parental and LapR cells, suggesting that mTORC1 activation in LapR cells was HER2-independent. Interestingly, mTORC1 activation in LapR cells was PI3K/Akt-independent, as p-Akt was completely inhibited by lapatinib in parental and LapR cells, while mTORC1 activation was maintained in LapR cells only. LapR cells were sensitive to mTORC1 and mTORC1/2 inhibition, but not to PI3K inhibition. Knockdown of the GTPase Rheb, which is known to promote mTORC1 activation, abolished mTORC1 activity in lapatinib-treated LapR cells, indicating that Rheb was required for mTOR activation in LapR cells. Surprisingly, several known mediators of Rheb/mTOR activation, such as TSC1/2, AMPK, the β-catenin pathway, and PRAS40, were not altered in their activation status in LapR cells compared with parental cells. This suggests that a potentially novel mechanism of mTOR activation may promote lapatinib resistance. These findings suggest the use of mTOR inhibitors in lapatinib-resistant breast cancers, and also may lead to novel basic mechanistic insights into mTOR signaling, which is commonly dysregulated in cancer.

Citation Format: Samuel W. Brady, Jian Zhang, Ming Horng Tsai, Dihua Yu. PI3K-independent, Rheb-mediated mTOR activation promotes lapatinib resistance. [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-221. doi:10.1158/1538-7445.AM2014-LB-221
Abstract LB-233: Unique physicochemical properties of the potent FGFR 1, 2, 3 and 4 inhibitor JNJ-42756493 contribute to prolonged target shutdown
Authors: Jovcheva Eleonora , Paulussen Caroline , Bergen Patrick Van , Chong Yolanda , Vialard Jorge , Mevellec Laurence , Angibaud Patrick , Perera Timothy
Published: May 2015

The ability of drugs to penetrate into cells and tissues is a fundamentally important property that is essential for the efficacy of drugs targeting intracellular processes. Many weakly basic small molecule drugs are known to accumulate extensively in acidic sub-cellular compartments such as lysosomes, through a process called ion trapping that is dependent on the physico-chemical properties of a compound. ‘Lysosomal uptake’ has been shown to significantly influence the activity of many agents, including anticancer drugs, both positively and negatively.

Here we describe the unique physico-chemical properties of JNJ-42756493, a potent inhibitor of fibroblast growth factor receptors (FGFRs) 1, 2, 3 and 4, currently undergoing clinical testing for the treatment of malignancies with FGFR pathway activating alterations. JNJ-42756493 has weakly basic and lipophilic characteristics, is highly permeable, and is fluorescent when exposed to UV light. The fluorescent property of JNJ-42756493 enabled rapid and convenient visualization of the drug (spatial and temporal localization) within the lysosomes of cultured cells exposed to JNJ-42756493. In order to evaluate the influence of this lysosomotropic property on the activity of JNJ-42756493, FGFR phosphorylation was monitored in a series of wash-out experiments performed in various cellular models with FGFR1 or FGFR2 amplifications. This comparative washout analysis demonstrated prolonged FGFR kinase inhibition by JNJ-42756493 in comparison to other FGFR inhibitors lacking lysosomotropic properties. This qualitative fluorescence-based data was complemented by accurate quantification of the amount of compound taken up by the cells through the use of radiolabelled JNJ-42756493.

Our results unequivocally demonstrate that JNJ-42756493 accumulates at high concentrations within the lysosomal compartment of cells without undergoing metabolism. The continued, long lasting effects on the target FGF receptor kinase inhibition following drug washout, suggest a novel intrinsic slow release of the unmodified drug from these intracellular stores. The lysosomotropic property of JNJ-42756493 is proposed to be a major contributor to the efficient and persistent inhibition of FGFR phosphorylation leading to potent cellular and in vivo activity.

Citation Format: Eleonora Jovcheva, Caroline Paulussen, Patrick Van Bergen, Yolanda Chong, Jorge Vialard, Laurence Mevellec, Patrick Angibaud, Timothy Perera. Unique physicochemical properties of the potent FGFR 1, 2, 3 and 4 inhibitor JNJ-42756493 contribute to prolonged target shutdown. [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-233. doi:10.1158/1538-7445.AM2014-LB-233
Abstract LB-236: Preclinical efficacy of targeting FGF autocrine signaling in mesothelioma with the FGF ligand trap, FP-1039/GSK3052230
Authors: Young M. Phillip De , Sherk Christian , Bleam Maureen , Barnette Mary , Ganji Gopi , Hoang Bao , Tunstead James , Bellovin David , Los Gerrit , Minthorn Elisabeth , Kumar Rakesh
Published: May 2015

Fibroblast growth factor (FGF) ligand-dependent signaling plays an important role in cancer development and tumor maintenance through autocrine production of FGFs directly from cancer cells and/or through paracrine production of FGFs from the local stroma. FGF-FGFR autocrine feedback loops have been characterized in several tumor types and may also play a role in drug resistance upon exposure to chemotherapy or targeted agents. FP-1039/GSK3052230 is a ligand trap that sequesters multiple FGFs and inhibits FGF receptor signaling. We previously demonstrated that increased FGF2 mRNA levels correlated with response to GSK3052230. To further extend this hypothesis, we investigated the preclinical efficacy of this drug in models of mesothelioma, a tumor type shown to express high levels of FGF2 mRNA in cell lines and in primary tumor specimens. GSK3052230 inhibited MAPK signaling as evidenced by decreased phospho-ERK levels in both NCI-H226 and MSTO-211H cells. When both cell lines were grown as tumor xenografts in mice, GSK3052230 inhibited tumor growth in a dose-dependent manner (NCI-H226: 16 - 78% TGI; MSTO-211H: 20 - 50% TGI). However, in contrast to what was observed in cultured cells, GSK3052230 had minimal effects on phospho-ERK levels in NCI-H226 tumors. Similarly, two genes downstream of ERK known to be regulated by FGF signaling, DUSP6 and ETV4, displayed modestly reduced mRNA levels upon GSK3052230 treatment. These data demonstrate the limitation of FGF pathway downstream signaling as a pharmacodynamic (PD) readout for this drug in this study despite observing significant tumor growth inhibition. Because FGFs also play a key role in angiogenesis, we explored the effects of GSK3052230 on tumor vessel formation in NCI-H226 xenografts as a potential approach to measure PD. Dose-dependent and statistically-significant reductions in tumor vessel density were observed in GSK3052230-treated tumors compared to vehicle-treated tumors using MECA-32 endothelial cell immunohistochemical staining. These data support the clinical evaluation of this drug in mesothelioma patients.

Citation Format: M. Phillip De Young, Christian Sherk, Maureen Bleam, Mary Barnette, Gopi Ganji, Bao Hoang, James Tunstead, David Bellovin, Gerrit Los, Elisabeth Minthorn, Rakesh Kumar. Preclinical efficacy of targeting FGF autocrine signaling in mesothelioma with the FGF ligand trap, FP-1039/GSK3052230. [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-236. doi:10.1158/1538-7445.AM2014-LB-236
Abstract LB-237: Targeting HER3 and IGF1R in NRG1 high lung squamous cell carcinoma
Authors: Sheng Qing , Pinzon-Ortiz Maria , Das Rita , Huang Alan , Rong Xianhui , Cao Z. Alexander
Published: May 2015

HER3 is a member of the ErbB family of receptor tyrosine kinases. Aberrant activation of HER3 as a result of HER2 amplification or neuregulin 1 (NRG1) over-expression has been demonstrated to mediate constitutive activation of downstream oncogenic signals. LJM716 is a fully human IgG1 anti-HER3 monoclonal antibody. It locks HER3 in an inactive conformation and prevents HER3 dimerization with other ErbB family members. This unique mode of action enables LJM716 to block both ligand dependent and ligand independent HER3 activation. In search of new indications that may benefit from anti-HER3 therapies, we noted that squamous cell carcinomas (SCC) tend to have relatively higher NRG1 expression as compared to their adenocarcinoma counterparts. Highest NRG1 expression was observed in the lung SCC cell lines in cell line encyclopedia (CLE). A subset of the lung SCC cell lines with high NRG1 expression are moderately sensitive to LJM716, with HER3 activation detected in all of the sensitive lines. Surprisingly, phosphorylation of IGF1R rather than other HER family members tracked closely to HER3 phosphorylation in the lung SCC lines. Consistent with this finding, co-treatment with either IGF1R inhibitor, OSI-906, or anti-IGF1R antibody, Figitumumab, with LJM716 further enhanced LJM716 activity in the three NRG1-high lung SCC lines in vitro. The enhanced anti-tumor activity of LJM716 and Figitumumab is also observed in mouse xenografts generated from these lung SCC lines. Furthermore, pharmacodynamic analysis revealed increased inhibition of PI3K/mTOR signaling with the combined treatment of LJM716 and Figitumumab. These data suggest that NRG1- driven HER3 activation is a common feature in a subset of lung squamous cell carcinoma. Combination of anti-HER3 and anti-IGF1R is effective at suppressing PI3K/mTOR signaling and inhibit growth in these tumors.

Citation Format: Qing Sheng, Maria Pinzon-Ortiz, Rita Das, Alan Huang, Xianhui Rong, Z. Alexander Cao. Targeting HER3 and IGF1R in NRG1 high lung squamous cell carcinoma. [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-237. doi:10.1158/1538-7445.AM2014-LB-237
Abstract LB-249: Coffee drinking decreases background DNA strand breaks in humans: A randomized controlled trial
Authors: Eisenbrand Gerhard , Bakuradze Tamara , Lang Roman , Hofmann Thomas , Schipp Dorothea , Galan Jens , Richling Elke
Published: May 2015

Effects of coffee consumption on the level of spontaneous DNA strand breaks in peripheral white blood cells have not been reported yet. In this human intervention study the impact of consuming a dark roast coffee blend on the level of spontaneous DNA strand breaks was investigated.

Healthy men (n=84) were randomized to consume daily for 4 weeks either 750 ml of fresh coffee brew or 750 ml of water, subsequent to a run in washout phase of 4 weeks. The study coffee was a blend providing substantial amounts of both, caffeoylquinic acids and the roast product N-methylpyridinium. Before and after the coffee/water phases, spontaneous strand breaks were determined by Comet assay.

Both groups exhibited a similar level of spontaneous DNA strand breaks at baseline.In the intervention phase spontaneous ( background) DNA strand breaks slightly increased in the water only group, whereas they significantly decreased in the coffee group,leading to a 27 percent difference between both arms (p=0.0002).

Food frequency questionnaires indicated no differences in the overall diet between groups, mean body weight during the intervention phases remaining stable. Consumption of the study coffee was found associated with a markedly lower level of pontaneous DNA strand breaks in white blood cells.

Conclusion: Regular coffee consumption contributes to DNA integrity.

Citation Format: Gerhard Eisenbrand, Tamara Bakuradze, Roman Lang, Thomas Hofmann, Dorothea Schipp, Jens Galan, Elke Richling. Coffee drinking decreases background DNA strand breaks in humans: A randomized controlled trial. [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-249. doi:10.1158/1538-7445.AM2014-LB-249
Abstract LB-251: p27Kip1 suppression of colitis-associated colon cancer mediated through cell intrinsic function in both mucosal epithelia and mucosal T cells
Authors: Choi Sung Hee , Kim Byung-Gyu , John Letterio J.
Published: May 2015

The cyclin-dependent kinase inhibitor p27Kip1 is a negative regulator of the cell cycle. Reduced expression of p27Kip1 has prognostic significance in several human epithelial cancers. Loss of p27Kip1 expression in cancer cells correlates with tumor aggressiveness, depth of tumor cell invasion and with lack of tumor cell differentiation. However, p27Kip1 also promotes apoptosis and contraction of effector CD4+ T cells, suggesting the potential that suppression of epithelial tumorigenesis may be linked to an intrinsic function of p27Kip1 in T cells. Here we show both mRNA and protein expression of p27Kip1 are significantly decreased in a murine model wherein a T cell-restricted deletion of the gene encoding the TGF-β intermediate, Smad4 (Smad4TKO), results in spontaneous colitis that invariably progresses to colon cancer by the age of 8 months. This phenotype is associated with a consistent decline in the mucosal expression of p27Kip1. To further investigate the role of p27Kip1 in the maintenance of intestinal mucosal homeostasis, we generated a ‘double knockout’ (Smad4TKO / p27Kip1-/- or ‘DKO’) mouse model in which a germ line p27Kip1 gene deletion (p27Kip1-/-) is combined with the T cell-restricted deletion of the Smad4 gene (Smad4TKO). All DKO mice develop spontaneous gastrointestinal inflammation and colon carcinoma by 1-2 months and 3 months of age, respectively. The p27Kip1 gene deletion, when combined with the T cell-restricted deletion of the Smad4 gene, leads to progressive inflammatory cytokine production (TNF-α, IFN-γ, iNOS, IL-6, IL-1β), activation of Stat1 and Stat3 and suppression of the expression of the tumor suppressor, 15-PGDH. Collectively our data suggest that p27Kip1 deficiency promotes gastrointestinal epithelial malignancy through both enhancement of proliferation of mucosal epithelial cells and through expansion of mucosal effector memory T cells.

Citation Format: Sung Hee Choi, Byung-Gyu Kim, Letterio J. John. p27Kip1 suppression of colitis-associated colon cancer mediated through cell intrinsic function in both mucosal epithelia and mucosal T 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 LB-251. doi:10.1158/1538-7445.AM2014-LB-251
Abstract LB-262: Phosphatidylserine-targeting antibody synergizes with anti-PD-1 antibody to inhibit tumor growth in K1735 mouse melanoma model
Authors: Huang Xianming , Ye dan , Brekken Rolf , Yin Yi
Published: May 2015

A large body of evidence indicates that PS is a major player in tumor-associated immunosuppression, including the induction and expansion of immune suppressor cells, such as MDSCs and M2 macrophages, and the production of immunosuppressive cytokines, such as TGF-beta and IL-10. Furthermore, PS also inhibits DCs maturation and antigen presentation. Thus, PS is a critical target for cancer immunotherapy. We have previously shown that anti-PS antibody can override PS-driven immunosuppression and re-program the tumor microenvironment from immunosuppressive to immunosupportive, breaks tumor immune tolerance and elicits potent de novo antitumor T-cell immunity. In the present study, we examined the combination of anti-PD-1 with anti-PS antibody in K1735 mouse melanoma model. Tumor-bearing mice were treated with each antibody alone or the combination at 2.5 mg/kg, twice a week. The combination treatment showed significantly superior tumor growth inhibition than with either antibody alone, animals treated with the combination survived significantly longer than with either antibody alone. Flow cytometry analysis showed the combination has the highest ratio of tumor-infiltrating immune effector to suppressor cells. Finally, no toxicity was observed in all treatment groups following multiple treatment doses. These data suggest that combination of PS blockade with immune checkpoint blockade represents a promising combinatorial strategy for cancer immunotherapy.

Citation Format: Xianming Huang, dan Ye, Rolf Brekken, Yi Yin. Phosphatidylserine-targeting antibody synergizes with anti-PD-1 antibody to inhibit tumor growth in K1735 mouse melanoma model. [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-262. doi:10.1158/1538-7445.AM2014-LB-262
Abstract LB-265: ONO-AE3-208 inhibits myeloid derived suppressor cells and glioma growth
Authors: Gary Kohanbash , Straw Erin , Averick Amram , Ahn Brian , Smith-Cohn Matthew , Ohkuri Takayuki , Kosaka Akemi , Okada Hideho
Published: May 2015

Myeloid Derived Suppressor Cells (MDSCs) are up-regulated in all known solid tumors and suppress anti-tumor T-cell activity. Our recent studies have demonstrated the ability of monocytic, Ly6C+ MDSCs to promote glioma growth through the activation of cyclooxygenase (COX)-2 pathway, which is responsible for plostaglandin-synthesis. ONO-AE3-208 is an antagonist of the prostaglandin E (EP)-4 receptor, which is an important positive feedback regulator of the COX-2 pathway. We thus examined the ability of ONO-AE3-208 to suppress MDSC activity in gliomas. ONO-AE3-208 treatment in mice bearing established GL261-quad glioma in the brain resulted in complete and persistent rejection of the tumors (n=4). Flow cytometric analysis revealed that gliomas in the ONO-AE3-208-treated mice were infiltrated by fewer numbers of Ly6C+ MDSCs compared with non-treated animals. We subsequently isolated glioma-infiltrating Ly6C+ MDSCs by flow-sorting to address their functions. RT-PCR analysis revealed that the Ly6C+ MDSCs derived from ONO-AE3-208 treated mice expressed lower levels of the Arg1 and Cox2 expression compared to control animals. Consistently, brain infiltrating leukocytes in ONO-AE3-208 treated tumor-bearing mice demonstrated enhanced Ifng expression compared with control mice, suggestive of enhanced T-cell activity. Our data demonstrate that ONO-AE3-208 may be useful in the treatment of glioma patients to suppress Ly6C+ MDSCs and promote anti-tumor immunity.

Citation Format: Kohanbash Gary, Erin Straw, Amram Averick, Brian Ahn, Matthew Smith-Cohn, Takayuki Ohkuri, Akemi Kosaka, Hideho Okada. ONO-AE3-208 inhibits myeloid derived suppressor cells and glioma growth. [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-265. doi:10.1158/1538-7445.AM2014-LB-265
Abstract LB-274: Mode of breast cancer detection: Do markers of tumor aggressiveness predict which tumors are “missed” at screening
Authors: Mahmoud Abeer Mostafa , Macias Virgilia , Kresovich Jacob K. , Kajdacsy-Balla Andre , Wiley Elizabeth L. , Rauscher Garth H.
Published: May 2015

Screening mammography reduces breast cancer stage at diagnosis by detecting it early before symptoms develop. Nonetheless, a breast cancer can arise as a lump despite a recent prior negative screen (“missed detection”). In the Breast Cancer Care in Chicago study, Non-Hispanic (nH) Black and Hispanic women were more likely than their nH White counterparts to report a missed detection despite a recent prior screening mammogram. We examined whether breast cancer subtype and immunohistochemical (IHC) markers of tumor aggressiveness predicted missed detection and whether they could explain racial/ethnic disparities in missed detection, in a subsample of 198 patients with a recent prior screening mammogram (63 Non-Hispanic White, 78 Hispanic and 57 African American).

Missed detection was defined as symptomatic awareness despite a negative screen in the prior 24 months. IHC analyses were conducted for estrogen receptor (ER), progesterone receptor (PR), HER2, EGFR and CK5/6, Ki67 and p53 expression. Breast cancers were classified as Luminal A (ER+/PR+/HER2-), Luminal B (ER+/PR+/HER2+), HER2 enriched (ER-/PR-/HER2+), and triple negative (TN) (ER-/PR-/HER2-).

Missed detection was highest for more aggressive TN and HER2 enriched subtypes (61% and 60%) and lowest for luminal A and B tumors (37% and 38%). Greater Ki67, EGFR and p53 expression were each associated with missed detection (p<0.02 for all), while PR and CK5/6 were marginally associated with missed detection. Before accounting for tumor characteristics, missed detection was twice as likely for minority than for nH white patients (47% vs. 24%, p=0.002); and the disparity in missed detected remained nearly the same after adjustment for tumor aggressiveness markers (47% vs. 27%, p=0.013)

In this multi-ethnic sample of breast cancer patients, markers of tumor aggressiveness were strongly associated with missed detection at screening but they did not explain racial/ethnic disparities in missed detection.

Citation Format: Abeer Mostafa Mahmoud, Virgilia Macias, Jacob K. Kresovich, Andre Kajdacsy-Balla, Elizabeth L. Wiley, Garth H. Rauscher. Mode of breast cancer detection: Do markers of tumor aggressiveness predict which tumors are “missed” at screening. [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-274. doi:10.1158/1538-7445.AM2014-LB-274
Abstract LB-283: A prospective study of breast cancer risk associated with occupational exposure to potentially endocrine disrupting compounds
Authors: Ekenga Christine C.
Published: May 2015

Background: Endocrine disrupting compounds, exogenous substances that interfere with normal endocrine functions, have been suspected to play a role in the etiology of breast cancer. The purpose of this study was to investigate the relationship between occupational exposure to potential endocrine disrupting compounds and breast cancer risk among women enrolled in the Sister Study, a prospective cohort study of US and Puerto Rican women designed to examine the genetic and environmental risk factors for breast cancer.

Methods: Over 50,000 women aged 33-74 enrolled in the Sister Study between 2004 and 2009. A comprehensive baseline questionnaire included questions about occupational exposures, including ever use and duration and frequency of use of nine agents containing potential endocrine disrupting compounds: Dyes or Inks, Gasoline or other Petroleum Products, Glues or Adhesives, Lubricating Oils, Metals, Paints, Pesticides, Organic Solvents, and Stains. Cumulative lifetime exposure to each potential endocrine disruptor was estimated and classified into quartiles. Study participants were prospectively followed from baseline until breast cancer diagnosis, death, or end of follow-up. Multivariable Cox proportional hazards regression was used to assess the impact of level of exposure (comparing each quartile of exposure with never exposure) to each of these compounds on breast cancer risk, adjusting for established breast cancer risk factors.

Results: Among the 47,755 women in the Sister Study with an occupational history, a total of 1798 cases of invasive breast cancer were diagnosed. Compared to their respective never exposure groups, an elevated risk of estrogen-receptor positive breast cancer was observed for women in the top quartile of occupational exposure to Dyes or Inks (HR: 1.7, 95%CI: 1.1-2.8). Non-significantly elevated risks were observed for women in the top quartile of occupational exposure to Gasoline or other Petroleum Products (HR: 1.7, 95%CI: 1.0-2.9) and Metals (HR: 1.5, 95%CI: 0.9-2.8).

Conclusions: Results suggest that exposure to occupational dyes or inks may influence breast cancer risk. Dyes and inks contain compounds with endocrine disrupting properties, including organic compounds and heavy metals. Further studies are necessary to elucidate the role of these potential endocrine disrupting compounds in breast cancer.

Citation Format: Christine C. Ekenga. A prospective study of breast cancer risk associated with occupational exposure to potentially endocrine disrupting compounds. [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-283. doi:10.1158/1538-7445.AM2014-LB-283
Abstract LB-305: Identification of p21 as a novel substrate of LATS2 in lung cancer
Authors: Yeung Benjamin
Published: May 2015

LATS2 is a serine/threonine kinase and tumor suppressor gene found to be downregulated and mutated in lung cancer. Although LATS2 has been shown to regulate many cancer-related functions such as maintenance of genomic stability, cell proliferation and apoptosis, its roles in lung tumorigenesis are largely unknown. In addition, the downstream cellular genes mediating LATS2 tumor suppressing function in lung cancer remains elusive. Since LATS2 kinase activity is essential for its function, therefore, identification and characterization of LATS2 substrates is critical in understanding the role it plays in lung tumorigenesis and is the focus of this study. To elucidate LATS2 function in lung cancer, we stably overexpressed LATS2 in a variety of lung cancer cell lines using a doxycycline-inducible lentivirus system. We have found that LATS2 strongly suppresses cell proliferation in all of cell lines tested. Further functional screening for LATS2 kinase substrates identified p21CIP1 to be a potential LATS2 substrate mediating LATS2 tumor suppressing function. p21 and LATS2 were found to bind each other as revealed by GST-pulldown and co-immunoprecipitation assays. Importantly, we found that LATS2 specifically phosphorylates p21 at S146, and that this site is critical for suppressing cell proliferation in lung cancer cells. These findings describe a novel LATS2 signalling pathway and improve our understanding of the role of LATS2 in lung tumorigenesis.

Citation Format: Benjamin Yeung. Identification of p21 as a novel substrate of LATS2 in 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 LB-305. doi:10.1158/1538-7445.AM2014-LB-305
Abstract LB-310: Single cell genome sequencing reveals clonal stability and diversity in breast cancer
Authors: Wang Yong , Navin Nicholas , Waters Jill , Leung Marco , Unruh Anna , Shi Xiuqing , Roh Whijae , Chen Ken , Scheet Paul , Vattathil Selina , Liang Han , Multani Asha , Zhang Hong , Meric-Bernstam Funda , Michor Franziska , Zhao Rui
Published: May 2015

Human breast cancers often display intratumor genomic heterogeneity. This clonal diversity confounds the clinical diagnosis and basic research of cancer, because single samples may not represent that tumor as a whole. Sequencing breast tumor cohorts en masse has identified many prevalent mutations, but has limited ability for resolving subclonal diversity. Here, we developed a whole-genome and exome single-cell sequencing approach (Nuc-Seq) using G2/M cells. To validate our method, we applied Nuc-Seq to sequence the whole genomes of two single cells from a genetically monoclonal breast cancer cell line (SK-BR-3) at high coverage depth (61X ± 5 sem, n=2) and breadth (83.70% ± 3.40 sem, n=2) to detect somatic mutations. Our analysis suggests that Nuc-Seq generates low allelic dropout rates (9.73% ± 2.19%) and low false positive error rates for point mutations (FPR = 1.24e-6). We then applied this method to sequence single normal and tumor cells from an estrogen-receptor positive breast cancer and a triple-negative ductal carcinoma at base-pair resolution. In parallel, we performed single cell copy number profiling. In both tumors, we observed a large number of rare variants that were not detected by sequencing the bulk tumor en masse. In contrast, we find that single cell copy number profiles are highly similar. Our data suggest that aneuploid rearrangements occurred early in tumor evolution and remained highly stable as the tumor mass expanded. In contrast we find that point mutations evolved gradually, generating extensive clonal diversity. Many of the diverse mutations were shown to occur at low frequencies (0.03 -10%) in the tumor mass by targeted duplex sequencing. Mathematical modeling suggests that the triple-negative tumor cells have an increased mutation rate (13.3X), while the ER+ tumor cells do not. These findings have important implications for the diagnosis, therapeutic treatment and evolution of chemoresistance in breast cancer.

Citation Format: Yong Wang, Nicholas Navin, Jill Waters, Marco Leung, Anna Unruh, Xiuqing Shi, Whijae Roh, Ken Chen, Paul Scheet, Selina Vattathil, Han Liang, Asha Multani, Hong Zhang, Funda Meric-Bernstam, Franziska Michor, Rui Zhao. Single cell genome sequencing reveals clonal stability and diversity in 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 LB-310. doi:10.1158/1538-7445.AM2014-LB-310
Abstract LB-311: Whole-exome sequencing of polycythemia vera revealed novel driver genes and somatic mutation shared by T cells and granulocytes
Authors: Wheeler David A. , Wang Linghua , Swierczek Sabina , Hickman Kimberly , Drummond Jennifer A. , Muzny Donna , Gibbs Richard A. , Prchal Joseph
Published: May 2015

Polycythemia vera (PV) is a myeloproliferative neoplasm characterized by augmented myelopoiesis leading to increased red cell mass with frequent excessive proliferation of other myeloid lineages. Over 95% of PV patients harbor JAK2V617F mutation, which confers proliferative advantage to affected myeloid progenitors. JAK2V617F, which is thought to be necessary but not sufficient for the disease, is often associated with acquired uniparental disomy on chromosome 9p (9pUPD). To better understand the underlying molecular basis of PV, we performed whole-exome sequencing and DNA copy-number analysis of 31 JAK2V617F-positive patients and further investigated the evolution of somatic mutations using longitudinal samples. In addition to JAK2 V617F and 9pUPD, we identified recurrent somatic mutation in an additional 5 genes including ASXL1, TET2, DNMT3A, and SF3B1 and recurrent DNA copy-number alterations at 1q and 18p. Forty-two percent of patients had at least one somatic mutation in an epigenetic modifier gene, and 23% of patients harbored mutation in RTK/RAS, RNA processing pathways, tumor suppressors and protein kinases. In 4 of 31 cases, variant allele abundance suggested somatic mutations of ASXL1, DNMT3A and SF3B1 may have preceded JAK2V617F. Interestingly, in 7 PV patients mutations also present in COSMIC were shared between the patients’ T-cell controls and granulocytes: 4 NF1, 2 ASXL1, and one each in TET2, IDH2, and DNMT3A, suggesting these genes mutated early in hematopoietic development. Absence of JAK2V617F in these T-cells ruled out cross-contamination of cell lineages. In an additional 4 cases, a minor JAK2V617F subclone acquired new mutations in DNMT3A, SF3B1, SMARCA2, and TET2 during PV progression. In summary, seventy percent of patients had mutation of at least one gene important to development of myeloid neoplasms, other than JAK2V617F. Our data reveal that these mutations, in particular NF1, may have arisen in some cases early in hematopoiesis but also in some patients during progression after diagnosis. These results suggest that the order of mutation is not as important as the total mutational burden in the development of PV.

Citation Format: David A. Wheeler, Linghua Wang, Sabina Swierczek, Kimberly Hickman, Jennifer A. Drummond, Donna Muzny, Richard A. Gibbs, Joseph Prchal. Whole-exome sequencing of polycythemia vera revealed novel driver genes and somatic mutation shared by T cells and granulocytes. [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-311. doi:10.1158/1538-7445.AM2014-LB-311
Abstract LB-316: The landscape of actionable genomic lesions in small cell bladder cancer
Authors: Chang Matthew T. , Asthana Saurabh , Iyer Gopakumar , Desai Neil , Al-Ahmadie Hikmat , Chapman Jocelyn , Bochner Bernard H. , Rosenberg Jonathan E. , Bajorin Dean F. , Solit David B. , Taylor Barry S.
Published: May 2015

Small cell cancers are aggressive tumors with unfavorable prognosis. Small cell bladder carcinomas are a particularly troublesome and poorly differentiated tumor where little is known and in which few targeted therapeutic options exist for molecularly defined patients. We therefore sought to characterize both common and actionable aberrant pathways in small cell bladder tumors to serve as a guide for therapeutic development. Utilizing a combination of deep targeted capture and whole-genome sequencing approaches, we characterized the mutational and DNA copy number alteration spectrum of twenty patients with small-cell bladder cancer including multi-region profiling of a subset of cases with mixed small cell and urothelial histologies. Integrating molecular, clinical, and pathway data along with comparative genomic analyses of 371 urothelial bladder and small cell lung cancers, we identified histology- and lineage-specific lesions and significant differences in the prevalence of specific pathway aberrations. Whole-genome sequencing revealed structurally complex tumors and, in some cases, somatic hypermutation, including one sample harboring more than 150,000 clonal mutations. Aberrations in G1/S cell cycle progression appear to be pathognomonic in small cell tumors. Furthermore, additional lesions affecting both pro/anti apoptotic as well as metabolic pathways occurred in patterns that are distinct from other small-cell and bladder cancers. In total, 85% of small cell bladder cancer samples contain at least one potentially clinically actionable lesion. These results indicate that integrative genomic analyses of small-cell bladder cancer facilitates therapeutic development and pathway targeting in a complex mutational landscape.

Citation Format: Matthew T. Chang, Saurabh Asthana, Gopakumar Iyer, Neil Desai, Hikmat Al-Ahmadie, Jocelyn Chapman, Bernard H. Bochner, Jonathan E. Rosenberg, Dean F. Bajorin, David B. Solit, Barry S. Taylor. The landscape of actionable genomic lesions in small cell bladder 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 LB-316. doi:10.1158/1538-7445.AM2014-LB-316