bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5166: Sensitivity of melanoma cells to a novel class of Ras inhibitors
Authors: Saville Kate M. , Lee Kevin , Mattox Tyler E. , Chen Xi , Valiyaveettil Jacob , Berry Kristy , Ramírez-Alcántara Veronica , Zhu Bing , Keeton Adam , Boyd Michael , Piazza Gary , Lindsey Ashley S.
Published: July 2017

A high percentage of human cancers arise from mutations in the ras gene that encodes an abnormal Ras protein locked in a constitutively active GTP-bound state that promotes tumor cell proliferation, survival, and metastasis. These gain-in-function mutations in the ras gene or constitutive activation of tyrosine kinase receptors upstream of the Ras protein drive tumor cell growth by activating Raf/MAPK and PI3K/AKT signaling pathways. Ras has been an elusive drug target for which no inhibitors are available to treat Ras-driven cancers. Screening a library of indene derivatives in a differential phenotypic assay identified a novel compound class displaying high potency and selectivity to inhibit the growth of tumor cells harboring mutant Ras relative to tumor cells with wild type (WT) Ras. Lead optimization resulted in a drug development candidate (DC070-547) and several back-up analogs (e.g. ADT-006) with IC50 values in the low nanomolar range and selectivity indices of 100 fold or greater to inhibit the growth of tumor cells with constitutively activated Ras relative to tumor cells with low levels of activated Ras. Sensitivity among a large panel of tumor cell lines to this compound class strongly correlated with levels of activated Ras, but did not appear to be limited to a specific ras gene mutation or Ras protein isoform. Here, we report that DC070-547 and ADT-006 potently and selectively inhibit the growth of the human melanoma cell line, SK-MEL-2, harboring a mutation in the ras gene that encodes the constitutively active N-Ras protein with IC50 values of 7 and 25 nM, respectively. In addition, both compounds potently inhibited the growth of the murine melanoma cell line, B16-F10 with WT ras, but harboring a mutation in a tyrosine kinase receptor upstream of Ras, specifically PDGFRα, which results in high levels of active, GTP-bound Ras as confirmed by Ras-RBD pull-down assays. To determine if treatment can disrupt Ras signaling, B16-F10 cells were incubated with the compounds before being subjected to Western blotting for phosphorylated signaling molecules downstream of Ras. Treatment reduced levels of phosphorylated c-Raf and MEK at concentrations that inhibit tumor cell growth. These findings support further investigation of this novel class of Ras inhibitors for the treatment of Ras-driven melanoma.

Citation Format: Kate M. Saville, Kevin Lee, Tyler E. Mattox, Xi Chen, Jacob Valiyaveettil, Kristy Berry, Veronica Ramírez-Alcántara, Bing Zhu, Adam Keeton, Michael Boyd, Gary Piazza, Ashley S. Lindsey. Sensitivity of melanoma cells to a novel class of Ras inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5166. doi:10.1158/1538-7445.AM2017-5166
Abstract 5172: E7386, an orally active CBP/beta-catenin modulator, induces T cells infiltration into tumor and enhances antitumor activity of anti-PD-1 mAb in Wnt1 tumor syngeneic mice model
Authors: Hori Yusaku , Yamada Kazuhiko , Kato Yu , Ozawa Yoichi , Odagami Takenao , Matsui Junji , Matsushima Tomohiro , Nomoto Kenichi , Kouji Hiroyuki , Owa Takashi
Published: July 2017

Recently, immunotherapeutic approaches have come to forefront in melanoma, non-small cell lung cancer, bladder cancer, and so on. However, sufficient benefits from these treatments have been limited. T cell infiltrating into tumor tissues is reported as one of the response biomarker candidates for the immune checkpoint inhibitors. Recent studies have shown that the activation of the Wnt/beta-catenin signaling pathway results in T cell exclusion and resistance to immune checkpoint inhibitor in melanoma patients. We established the Wnt1 tumor syngeneic mice model (Wnt1 model) by implantation of mammary adenocarcinomas isolated from MMTV-Wnt1 transgenic mice. Here we demonstrate whether E7386, a first-in-class orally active CBP/beta-catenin modulator, affects the recruitment of T cells into tumor tissues, leading to the enhancement of anti-PD-1 mAb in Wnt/beta-catenin signaling pathway activating tumor model. The mice were treated with E7386 (50 mg/kg, orally, BID) and/or anti-mouse PD-1 mAb (10 mg/kg, intraperitoneal, twice a week) for three weeks. Tumor diameters are measured with digital calipers, and the tumor volume in mm3 is calculated. Immunohistochemical (IHC) analysis was evaluated for tumor-infiltrating T cells. E7386 showed significant antitumor activity in Wnt1 model, but anti-PD-1 mAb did not. In contrast, E7386 with anti-PD-1 mAb indicated prominent antitumor activity compared to each single treatment. Enhancement of body weight loss in combination group was not observed. In IHC analysis, infiltration of T cells was limited in vehicle control group, in contrast T cell infiltration into tumors was clearly observed in both E7386 treatment group and combination group. As a result, antitumor activity of immune checkpoint inhibitor was limited in Wnt-driven tumor model and E7386 as a novel CBP/beta-catenin modulator enhanced the antitumor activity of anti-PD-1 mAb via induction of tumor-infiltrating T cells.

Citation Format: Yusaku Hori, Kazuhiko Yamada, Yu Kato, Yoichi Ozawa, Takenao Odagami, Junji Matsui, Tomohiro Matsushima, Kenichi Nomoto, Hiroyuki Kouji, Takashi Owa. E7386, an orally active CBP/beta-catenin modulator, induces T cells infiltration into tumor and enhances antitumor activity of anti-PD-1 mAb in Wnt1 tumor syngeneic mice model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5172. doi:10.1158/1538-7445.AM2017-5172
Abstract 5178: CB002, a novel p53 pathway-restoring compound that induces apoptosis through the pro-apototic protein NOXA
Authors: Borrero Liz J. Hernandez , Zhang Shengliang , Dicker David T. , El-Deiry Wafik S.
Published: July 2017

P53 is a transcription factor that becomes stimulated upon genotoxic and cellular stress signals ultimately leading to the transcriptional activation of genes involved in processes such as DNA repair, cell cycle arrest, and apoptosis etc. TP53 is the most commonly mutated tumor suppressor and this is associated with cancer initiation, cancer progression and therapy resistance. P53-targeted therapy has proven to be challenging because direct functional restoration of p53 as a transcription factor has been difficult to achieve. We haven taken a different approach by investigating small molecules that functionally restore the p53-signaling pathway instead of direct p53 targeting. To date there is no approved drug that restores the p53 pathway in cancer cells with mutant p53. Therefore, we performed a high-throughput screen to identify such molecules. We identified a family of small molecules, CB002 and its structural analogs, as candidates for restoration of the p53 pathway in p53-null and mutant p53-expressing cancer cells. CB002 was specific in causing apoptosis in colorectal cancer cells and not in normal human fibroblasts cells as indicated by a Sub-G1 assay. Utilizing the xCELLigence RTCA DP system and CIM-Plate we show that CB002 treatment decreases the ability of colorectal cancer cells to migrate. The ability of CB002 to restore the p53 pathway was validated by studying the activation of p53 target genes p21, DR5, and NOXA in various cancer cell lines and expression of well-established apoptotic markers. Stable knockdown of NOXA completely abrogated the expression of cleaved PARP and reduced Sub-G1 cells, implicating the relevance of NOXA as a key mediator of cell death induction by CB002. We are currently exploring the mechanism by which NOXA induces apoptosis, as preliminary results suggest that degradation of Mcl-1 is not required for CB002 mediated cell death. In addition, we are evaluating the ability of CB002 structural analogs in decreasing the stability of mutant p53 using a larger panel of p53 mutants, as CB002 appears to target R175H p53 mutants. Our data supports the continued investigation of CB002 as a p53 pathway-restoring compound that may be further developed as a cancer therapeutic for p53-null tumors as well as tumors with p53 mutations.

Citation Format: Liz J. Hernandez Borrero, Shengliang Zhang, David T. Dicker, Wafik S. El-Deiry. CB002, a novel p53 pathway-restoring compound that induces apoptosis through the pro-apototic protein NOXA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5178. doi:10.1158/1538-7445.AM2017-5178
Abstract 518: Synergistic effects of dual inhibition of YAP1 and TAZ in non-small cell lung cancer cells
Authors: Shum Elaine , Liu Huijie , Zhu Liang , Perez-Soler Roman , Halmos Balazs , Cheng Haiying
Published: July 2017

Background: The Hippo signaling pathway is associated with regulation of cell growth and apoptosis. Downstream effectors of this pathway, YAP and its paralog, TAZ, interact with TEA domain (TEAD) transcription factors leading to cell proliferation and anti-apoptosis. As a result, YAP and TAZ have emerged as attractive anti-cancer therapeutic targets. Several studies, including our previous report, have noted the individual effects of YAP or TAZ ablation; however, consequences of dual inhibition have not yet been investigated in lung cancer. We hypothesize that dual inhibition of YAP and TAZ will lead to more pronounced cytotoxicity than each knockdown alone as a result of diminished compensatory mechanism by the remaining family member.

Methods: NSCLC cell lines, such as PC9 and A549, were transfected with individual YAP1, TAZ siRNA or a combination of both siRNAs. Western blotting was performed to determine the levels of YAP1 and TAZ proteins following knockdown. Quantitative RT-PCR was also performed to confirm effective YAP1 and TAZ knockdown. In addition, gene and protein expression of downstream targets, such as CTGF and Cyr61, were assessed. Clonogenic assays were performed to determine cell survival.

Results: Successful siRNA-mediated YAP and TAZ ablation were confirmed with Western blot and qRT-PCR. The expression of the Hippo-YAP/TAZ downstream targets, CTGF, Cyr61 and AXL, were also reduced accordingly. Moreover, dual knockdown of YAP and TAZ led to a more pronounced inhibition of cell survival/proliferation than ablation of individual genes alone. In addition, dual inhibition of YAP/TAZ exhibited significantly diminished levels of the mesenchymal markers, vimentin and N-cadherin, and increased levels of the epithelial marker, E-cadherin. EMT has been recognized as an essential process during lung cancer tumor migration and metastasis.

Conclusion: Our findings show that dual inhibition of YAP1 and TAZ are synergistic in blocking NSCLC cell survival signaling. Thus, dual inhibition may serve as a better therapeutic strategy in targeting the Hippo pathway than sole YAP1 blockade in the management of NSCLC.

Citation Format: Elaine Shum, Huijie Liu, Liang Zhu, Roman Perez-Soler, Balazs Halmos, Haiying Cheng. Synergistic effects of dual inhibition of YAP1 and TAZ in non-small cell lung cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 518. doi:10.1158/1538-7445.AM2017-518
Abstract 5180: Effects of soy isoflavones and SRC inhibitors on metastatic activity in prostate cancer
Authors: Rice Lori P. , Siemann Dietmar W.
Published: July 2017

Background: In advanced prostate cancer (PCa), cells escape from the primary tumor and enter the bloodstream, preferentially targeting the bone. This results in weakened bones, spinal compressions, fractures and intense pain. Efforts to interfere with early steps in the metastatic cascade by affecting the tumor microenvironment have led to the development of promising small molecule targeting agents. The tyrosine kinase inhibitors, saracatinib and dasatinib, have been shown to inhibit activation of Src and downstream effectors thought to be involved in cancer cell dissemination. Soy-derived isoflavones (ISFs) have been shown to have cytostatic effects on PCa cells without toxicity.

Aim: The aim of these studies was to determine if ISFs enhance the effects of Src inhibitors on PCa cells, resulting in lower doses of these agents needed to produce optimum results.

Methods: PC-3 ML and LNCaP cells were treated with either a Src inhibitor (dasatinib or saracatinib), a soy isoflavone extract (ISFs), or a combination. Modified Boyden transwell chambers were used to evaluate migration and invasion. Cell cycle and proliferation were measured using FACS analyses and trypan blue staining, respectively.

Results: ISFs and Src inhibitors did not cause cytotoxicity or reduce proliferation. However, Src inhibitors produced an increase in cells in G1 phase, while ISFs increased cells in G2/M phase. When ISFs were combined with Src inhibitors, both phases were increased with a concomitant decrease in S phase cells. In transwell migration studies, all agents significantly decreased the number of cells found on the bottom of the membrane: dasatinib>saracatinib>ISFs. Lower doses of Src inhibitors were needed to produce inhibition of migration when ISFs were added to the treatment. Invasion studies with PC-3 ML and LNCaP cells suggest that ISFs can reduce metastatic activity by 39% and 35%, respectively. Therefore, by adding ISFs, lower doses of inhibitors might be used to achieve optimal response and decrease toxicity.

Conclusions: In vitro studies suggested that a combination of a Src inhibitors and ISFs, at non-cytotoxic doses, results in greater inhibition of metastatic or invasion activity than either alone. Further studies are needed to determine if this strategy could be used clinically to treat patients with lower doses of small molecule inhibitors by including soy isoflavone concentrates in the treatment regimen.

Citation Format: Lori P. Rice, Dietmar W. Siemann. Effects of soy isoflavones and SRC inhibitors on metastatic activity in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5180. doi:10.1158/1538-7445.AM2017-5180
Abstract 5184: Radiosensitizing effect of lapatinib in HER2-overexpressing breast cancer cells: scientific rationale for RTOG1119 study
Authors: Yu Tosol , Cho Bong Jun , Choi Eun Jung , Park Ji Min , Kim Dan Hyo , Kim In Ah
Published: July 2017

Trastuzumab has been widely used for the treatment of human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer, however, it cannot easily cross the blood-brain barrier (BBB) and is known to increase the incidence of brain metastases. In contrast, lapatinib has a low molecular weight and can cross the BBB and it could be useful to treat brain metastases in patients with HER2-positive breast cancer. To explore the impact of lapatinib on radiation response, we conducted an in vitro experiment using SKBR3 and BT474 breast carcinoma cells exhibiting HER2/neu amplification. Lapatinib down-regulated phosphorylated p-HER2, p-EGFR, p-AKT, and p-ERK. Pretreatment of lapatinib increased the radiosensitivity of SKBR3 (sensitizer enhancement ratio [SER]: 1.21 at a surviving fraction of 0.5) and BT474 (SER: 1.26 at a surviving fraction of 0.5) cells and hindered the repair of DNA damage, as suggested by the prolongation of radiation-induced γH2AX foci and the down-regulation of phosphorylated DNAdependent protein kinase, catalytic subunit (p-DNAPKcs). Increases in radiation-induced apoptosis and senescence were suggested to be the major modes of cell death induced by the combination of lapatinib and radiation. Furthermore, lapatinib did not radiosensitize a HER2- negative breast cancer cell line or normal human astrocytes. These results suggest that lapatinib can potentiate radiation-induced cell death in HER2-overexpressing breast cancer cells and may increase the efficacy of radiotherapy. Based on these findings, RTOG1119 study which is a phase II randomized study for lapatinib combined with radiation therapy in patients with brain metastases from HER2-positive breast cancer is ongoing (NCT 01622868).

Citation Format: Tosol Yu, Bong Jun Cho, Eun Jung Choi, Ji Min Park, Dan Hyo Kim, In Ah Kim. Radiosensitizing effect of lapatinib in HER2-overexpressing breast cancer cells: scientific rationale for RTOG1119 study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5184. doi:10.1158/1538-7445.AM2017-5184
Abstract 5193: Hafnium oxide nanoparticles (NBTXR3), a novel radiation enhancer achieves marked antitumor efficacy across five tumor types
Authors: Zhang Ping , Vivet Sonia , Paris Sébastien , Pottier Agnès
Published: July 2017

NBTXR3 are hafnium oxide nanoparticles (NPs) used for a single intratumor administration as radioenhancer in combination with radiation therapy (RT) as part of multi-modality of cancer treatment. The size, shape and surface of the NPs have been designed to develop strong interactions with cancer cells - effective cell binding and uptake - and to persist within the tumor mass during the whole RT treatment. The high electron density of the NPs is responsible for an increased probability of interaction with incoming ionizing radiations (when compared to tumor tissues with low electron density) and an increased energy dose deposition within the cancer cells which results in an enhanced tumor destruction when compared to RT alone. NBTXR3 works similar to the physical mode of action of RT, it does not rely on any biological system or target and constantly amplifies the radiation dose deposition (“on/off” activation). Here we present the transferability of the approach from one type of cancer to the other evaluating (i) the feasibility of the intratumor injection (intratumor availability of NBTXR3 nanoparticles by Computed Tomography (CT) or µCT) and (ii), the antitumor efficacy of NBTXR3 exposed to radiation. NBTXR3 NPs demonstrated a good intratumor availability and persistence across all tested tumor models (epithelial or mesenchymal origin), including human PDX tumor models. Notably, in PAC-120 tumor model the persistence of NBTXR3 NPs within the tumor mass was observed for more than 50 days which is equivalent to the entire duration of RT treatment. The antitumor efficacy was systematically enhanced in terms of tumor growth delay for animals treated with NBTXR3 and exposed to RT when compared to RT alone. NBTXR3 is currently in clinical trials in seven cancer indications including: soft tissue sarcoma, head and neck (H&N), liver, rectal and prostate. These preclinical studies support the rationale for the development of NBTXR3 across all cancer indications where radiation treatment is used.

NBTXR3 intratumor availability and antitumor efficacyTumor modelX-ray sources (antitumor efficacy)CT or µCTSarcomaHT1080200kV, Ir192LPS80T3 (PDX)200kV, Co60xA673Co60ProstatePC3150kVxDU145200kVxPAC120 (PDX)xH&NCAL33200kVxFaDu200kVxColorectalHCT116Ir192xLungNCI-H460-luc2200kVx

Citation Format: Ping Zhang, Sonia Vivet, Sébastien Paris, Agnès Pottier. Hafnium oxide nanoparticles (NBTXR3), a novel radiation enhancer achieves marked antitumor efficacy across five tumor types [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5193. doi:10.1158/1538-7445.AM2017-5193
Abstract 5195: Modulating the UPR using the impridone ONC201 to change the impact of radiation on prostate cancer cells
Authors: Amoroso Francesca , Pickard Adam , McNaney Alice , Tarapore Rohinton , Allen Joshua E. , Mills Ian G.
Published: July 2017

Prostate cancer is the highest incidence non-cutaneous cancer in men, and a significant cause of cancer mortality. Localized disease is treated with surgery or radiotherapy and whilst androgen deprivation therapy can extend survival in the subset of cases that progress, metastatic disease is incurable. We have found that oncogenic drivers of prostate cancer, as well as therapy, lead to changes in the activation of prostate cancer cell stress signaling pathways and in particular the unfolded protein response (UPR). We have previously reported that the androgen receptor sustains the cytoprotective activity of the IRE1-XBP1 arm of the UPR and represses the activation of the PERK-ATF4 arm. We showed that treating prostate cancer cells with radiation leads to the activation of all three arms of the UPR, culminating in treatment resistance in surviving cells. In this study we assess whether the activation of the UPR in response to radiation mirrors the immunogenic/inflammatory response, which is known to occur in an initially acute apoptotic phase before resolving to a chronic sustainable level. Further we have evaluated the impact of combining radiation with ONC201, a novel anti-cancer small molecule in clinical trials that is an activator of the UPR, on the viability of prostate cancer. We find that ONC201 has a delayed cytotoxic effect as a single agent, with the impact on viability occurring from 72 hours onwards at low microMolar concentrations. However activation of multiple arms of the UPR occurs earlier and is detectable at 24 hours for ATF4, ATF6 and IRE1-XBP1 at the protein/mRNA levels. This time difference creates a window in which to introduce sequential administration of radiation to test ONC201 as a primer for cytotoxic response radiation. We have undertaken this work in a panel of cell-lines (PC3, DU145 and AR-expressing cell-lines) in which we have also knocked down key regulators (PERK, IRE1, CHOP) of separate arms of the UPR. This represents the first in vitro study to characterise the impact of ONC201 on the radiation-responsiveness of prostate cancer cells.

Citation Format: Francesca Amoroso, Adam Pickard, Alice McNaney, Rohinton Tarapore, Joshua E. Allen, Ian G. Mills. Modulating the UPR using the impridone ONC201 to change the impact of radiation on prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5195. doi:10.1158/1538-7445.AM2017-5195
Abstract 5201: PSMA-targeted alpha radioimmunotherapy for prostate cancer with 225Ac-J591
Authors: Batra Jaspreet S. , Liu He , Kim Sae , Navarro Vicente N. , Vallabhajosula Shankar , Tagawa Scott T. , Bander Neil H.
Published: July 2017

Background: Prostate cancer (PC) is a radiosensitive disease. In addition to external beam and brachytherapy, systemic bone-seeking radioisotopes have been utilized clinically for many years, with radium-223 leading to overall survival benefits. However, the available beta and alpha emitting particles in the clinic target tumors / stroma in bone only. Biologically targeted radiopharmaceutical treatment has shown promising results in our earlier multiple clinical trials using beta-emitting anti-PSMA therapy with Leutetium-177 radiolabeled anti-PSMA monoclonal antibody (mAb) J591, with accurate targeting and tumor response, but treatment is limited by myelosuppression. Both beta and alpha-small molecule PSMA ligand directed therapy has been utilized anecdotally outside of the US, but has not been systemically studied. Based upon their biodistribution, targeting of salivary glands and potentially proximal renal tubules may pose longer term toxicity issues. mAb-based targeted alpha-particle delivery may be advantageous with less expected myelosuppression than seen with β-emitters.

Experimental procedures: To optimize labeling of humanized DOTA-J591 mAb, actinium-225 (225Ac) nitrate was obtained from Oak Ridge National Laboratories and was dissolved in HCl solution and then mixed with trimethyl ammonium acetate and L-ascorbic acid. This preparation was incubated with DOTA-J591. The labeling efficiency (LE) was determined by ITLC-SG. If the LE is >60%, 225Ac-DOTA-J591 mAb was purified by gel filtration and sterilized by membrane filtration. In a pilot pre-clinical study, we studied the toxicity in non-tumor bearing BALB/c mice.

Results: The radiochemical purity is >95% and the immunoreactivity was >80%. Twenty-five BALB/c mice received from 2.1 to 6.3 KBq of 225Ac-J591. Treatment was well tolerated, with all mice alive and healthy at Day 26.

Conclusions: A stable alpha emitting-antibody complex has been produced with 225Ac-J591. Initial mouse safety experiments have been successful. A RIT dose escalation study of PSMA-targeted alpha emitter in a LNCaP xenograft model is underway.

Citation Format: Jaspreet S. Batra, He Liu, Sae Kim, Vicente N. Navarro, Shankar Vallabhajosula, Scott T. Tagawa, Neil H. Bander. PSMA-targeted alpha radioimmunotherapy for prostate cancer with 225Ac-J591 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5201. doi:10.1158/1538-7445.AM2017-5201
Abstract 5209: Ionizing radiation abrogates pro-tumorigenic effects from cancer-associated fibroblasts in xenografts
Authors: Hellevik Turid , Grinde Maria T. , Vik Jørg , Camilio Ketil A. , Martinez-Zubiaurre Inigo
Published: July 2017

Non-malignant elements of tumors play fundamental roles in both cancer sustainability and responses

to therapies. In the context of clinical radiotherapy (RT), all cells that reside in the tumor mass receive

radiation, but the impact of cancer-associated fibroblasts (CAFs) to treatment outcomes remains largely

unexplored. In this study, we have investigated the effects of radiation on the natural pro-tumorigenic

actions of CAFs in animals. Ionizing radiation (IR) was delivered to CAFs either as a single-high dose

or fractionated medium doses. Tumor development was compared in xenografts after co-implantation

of A549 lung tumor cells with irradiated or non-irradiated human lung CAFs. Quantitative histology

and immunohistochemistry was applied to investigate potential biological mechanisms behind tumor

growth regulations. As expected, CAFs showed resistance to radiation-induced cell death, however, the

enhanced tumorigenic effects observed with admixed non-irradiated CAFs was nullified. Quantitative

determinations of parameters such as desmoplasia, angiogenesis, inflammation, innate immunity or

tumor cell proliferation revealed enhanced blood vessel density in tumors established with irradiated

CAFs. Experiments to ascertain fate of implanted CAFs showed that both irradiated and non-irradiated

CAFs only reside at the implantation site during early stages, suggesting that the regulatory functions of

admixed CAFs may take place during the initial phases of tumor formation. In this study, we show that

CAFs receiving ionizing radiation lose their pro-tumorigenic potential in vivo, affecting angiogenesis

and possibly other mechanisms related to tumor engraftment. This finding represent a previously

unknown advantageous effect induced by radiotherapy, which adds to the well-known direct cytotoxic

effects on transformed epithelial cells.

Note: This abstract was not presented at the meeting.

Citation Format: Turid Hellevik, Maria T. Grinde, Jørg Vik, Ketil A. Camilio, Inigo Martinez-Zubiaurre. Ionizing radiation abrogates pro-tumorigenic effects from cancer-associated fibroblasts in xenografts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5209. doi:10.1158/1538-7445.AM2017-5209
Abstract 5211: Hormophysa triquerta polyphenol, an elixir that deters CXCR4- and COX2-dependent dissemination destiny of treatment-resistant pancreatic cancer cells
Authors: Aravindan Sheeja , Ramraj Sathish Kumar , Somasundaram Dinesh Babu , Kandasamy Kathiresan , Thirugnanasambandan Somasundaram S. , Herman Terence , Aravindan Natarajan
Published: July 2017

Therapy resistant pancreatic cancer (PC) cells play a crucial role in tumor relapse, recurrence, and metastasis. Recently, we showed the anti-PC potential of an array of seaweed polyphenols and identified efficient drug deliverables. Herein, we investigated the benefit of one such deliverable, Hormophysa triquerta polyphenol (HT-EA), in regulating the dissemination physiognomy of therapy resistant PC cells in vitro, and residual PC in vivo. Human PC cells exposed to clinical radiation (FIR), with/without HT-EA pretreatment were examined for the alterations in the tumor invasion/metastasis (TIM) transcriptome (93 genes, QPCR-profiling). Utilizing a mouse model of residual PC, we investigated the benefit of HT-EA in the translation regulation of crucial TIM targets (TMA-IHC). Radiation activated 30, 50, 15, and 38 TIM molecules in surviving Panc-1, Panc-3.27, BxPC3, and MiaPaCa-2 cells. Of these, 15, 44, 12, and 26 molecules were suppressed with HT-EA pretreatment. CXCR4 and COX2 exhibited cell line-independent increases after FIR, and was completely suppressed with HT-EA, across all PC cells. HT-EA treatment resulted in translational repression of FIR-induced CXCR4, COX2, β-catenin, MMP9, Ki-67, BAPX, PhPT-1, MEGF10, and GRB10 in residual PC. Muting CXCR4 or COX2 regulated the migration/invasion potential of IR-surviving cells, while forced expression of CXCR4 or COX2 significantly increased migration/invasion capabilities of PC cells. Further, treatment with HT-EA significantly inhibited IR-induced and, CXCR4/COX2 forced expression-induced PC cell migration/invasion. This study (i) documents the TIM blueprint in radiotherapy-resistant PC cells, (ii) defines the role of CXCR4 and COX2 in induced metastatic potential, and (iii) recognizes the potential of HT-EA in deterring the CXCR4/COX2-dependent dissemination destiny of therapy resistant residual PC cells.

Citation Format: Sheeja Aravindan, Sathish Kumar Ramraj, Dinesh Babu Somasundaram, Kathiresan Kandasamy, Somasundaram S. Thirugnanasambandan, Terence Herman, Natarajan Aravindan. Hormophysa triquerta polyphenol, an elixir that deters CXCR4- and COX2-dependent dissemination destiny of treatment-resistant pancreatic cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5211. doi:10.1158/1538-7445.AM2017-5211
Abstract 5214: Activation of WNT/b-catenin signaling results in resistance to PI3K/mTOR dual inhibitor in co-existing KRAS and PIK3CA mutant colorectal cancer cells
Authors: Park Ye-Lim , Kim Hwang-Phill , Cheon Seul-Ki , Kang Jun-Kyu , Lim Yoojoo , Song Sang-Hyun , Han Sae-Won , Kim Tae-you
Published: July 2017

KRAS is a frequently mutated gene in colorectal cancer. In addition, PIK3CA mutations commonly co-exist with KRAS mutations and lead to additive activation of the PI3K/mTOR signaling pathway. Here, we investigated preclinical activity of gedatolisib, a PI3K/mTOR dual inhibitor, to identify mechanism of inhibition of PI3K/mTOR in 28 colorectal cancer (CRC) cells. Cells specifically with PIK3CA mutation were sensitive while those with KRAS mutation were resistant to gedatolisib. 9 out of 28 CRC cells harbor PIK3CA & KRAS co-mutation and 7 out them were shown to be sensitive to gedatolisib. However, HCT15 and LS174T cells were resistant. We identified that resistant cell lines have high activity of GSK3B and TCF7 frameshift mutation (465insertC466;H155fs*), which functions as positive regulator of WNT/b-catenin pathway. The effects of GSK3B-knockdown showed decreased activity of mTOR downstream molecules in gedatolisib-treated resistant cells. Interestingly, these effects also caused a decrease in activity of WNT/b-catenin pathway. In addition, combination treatment of gedatolisib and CHIR-99021, GSK3B inhibitor, resulted in significantly enhanced cytotoxicity against gedatolisib-resistant TCF7 frameshift mutant cells. Taken together, these show that aberrant regulation of WNT/b-catenin pathway and high activity of GSK3B by TCF7 frameshift mutation cause resistance to PI3K/mTOR dual inhibitor. Inhibition of GSK3B activity in colorectal cancer cells with KRAS and PIK3CA co-mutations increases sensitivity to PI3K/mTOR dual inhibitor.

Citation Format: Ye-Lim Park, Hwang-Phill Kim, Seul-Ki Cheon, Jun-Kyu Kang, Yoojoo Lim, Sang-Hyun Song, Sae-Won Han, Tae-you Kim. Activation of WNT/b-catenin signaling results in resistance to PI3K/mTOR dual inhibitor in co-existing KRAS and PIK3CA mutant colorectal cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5214. doi:10.1158/1538-7445.AM2017-5214
Abstract 5218: Breast cancer resistance protein (ABCG2) and P-glycoprotein (ABCB1) transport ibrutinib and may restrict its oral availability and brain accumulation, whereas CYP3A4 limits ibrutinib oral availability
Authors: Hoppe Stephanie van , Rood Gert-Jan , Wagenaar Els , Sparidans Rolf , Beijnen Jos , Schinkel Alfred
Published: July 2017

Introduction: Ibrutinib (Imbruvica, PCI-32765) is an orally administered tyrosine kinase inhibitor (TKI) approved by the FDA in 2014 for treatment of B-cell malignancies. Ibrutinib is a confirmed irreversible inhibitor of Bruton tyrosine kinase (BTK) with promising clinical activity and tolerability in B-cell malignancies. Ibrutinib is converted into several metabolites, primarily by CYP3A4. Its main metabolite, PCI45227, has an inhibitory activity towards BTK approximately 10 times lower than its parent compound. We investigated whether ibrutinib is a substrate for the multidrug efflux transporters ABCG2 and ABCB1 and whether these transporters influence oral availability and brain and other tissue accumulation of ibrutinib.

Materials: We used in vitro transport assays to assess human (h)ABCB1-, hABCG2- or murine (m)Abcg2-mediated transport of ibrutinib. To study the single and

combined roles of Abcg2 and Abcb1a/1b in oral ibrutinib disposition, we used appropriate knockout mouse strains. To assess the role of Cyp3a in the bioavailability of ibrutinib we used knockout strains as well as humanized CYP3A4 strains and measured the ibrutinib and PCI45227 concentrations at various time points.

Results: Ibrutinib was transported reasonably well by hABCB1 and mAbcg2, but not by hABCG2 in vitro. Upon oral administration of ibrutinib, Cyp3a-/-, Abcg2-/-, Abcb1a1b-/-, and Abcg2;Abcb1a1b-/- mice displayed an increase of 9.8-, 1.3-, 1.6- and 1.1 fold in ibrutinib plasma AUC0-20min compared to wild-type mice. At 20 min, preliminary data indicated that the relative brain accumulation of ibrutinib was not significantly altered for the Abcg2;Abcb1a/1b-/- mice compared to wild-type mice.

Conclusion: Abcg2 and Abcb1a/1b possibly restrict oral availability of ibrutinib. Based on our (preliminary) data ibrutinib may not substantially cross the blood-brain barrier. Cyp3a restricts the oral availability of ibrutinib and therefore inhibition of this enzyme may be of clinical importance for patients undergoing ibrutinib therapy.

Citation Format: Stephanie van Hoppe, Gert-Jan Rood, Els Wagenaar, Rolf Sparidans, Jos Beijnen, Alfred Schinkel. Breast cancer resistance protein (ABCG2) and P-glycoprotein (ABCB1) transport ibrutinib and may restrict its oral availability and brain accumulation, whereas CYP3A4 limits ibrutinib oral availability [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5218. doi:10.1158/1538-7445.AM2017-5218
Abstract 5227: Synthesis of a biotin probe for identification of the ajoene protein targets in cancer cells ajoene protein targets in cancer cells
Authors: Kaschula Catherine H. , Kusza Daniel A. , Schafer Georgia , Katz Arieh A. , Singh Shivendra V. , Hunter Roger
Published: July 2017

Garlic (Allium sativum) is a medicinal plant belonging to the lily family which has been used since ancient times for its beneficial health effects which include protection against infections and cancer. There are a cluster of bioactive compounds found in crushed garlic which contain sulfide or polysulfide functional groups. One of these compounds, ajoene, is able to interfere with biological processes by undergoing thiolysis exchange reactions with biological thiols, for example glutathione and cysteine residues on proteins. Importantly, ajoene is cytotoxic to cancer cells in the low micromolar range. We have previously found that ajoene targets multiple proteins in cancer cells and the aim of this project is to identify the specific protein targets of ajoene. To achieve this aim, we have synthesized a “tagged” ajoene analogue containing a biotin functional group. As biotin may alter the biological properties of ajoene, our strategy was to initially synthesize an azide-containing ajoene analogue (called azide-ajoene) using our 4-step synthetic route to ajoene analogues previously published. Azide-ajoene was found to retain cancer cell cytotoxicity similar to that of the parent ajoene. We then treated cancer cells (MDA-MB-231 breast and WHCO1 oesophageal cancer) with azide-ajoene to allow transfer of an azide label to the protein targets during thiolysis exchange with ajoene. We then collected lysate from the treated cells and performed an in vitro click reaction with a separately synthesized biotin-alkyne partner which was synthesized via a series of substitution and amide coupling reactions. Click chemistry covalently links biotin to the ajoene-tagged protein via a triazole linkage; and the feasibility of this method was validated by western blot. The biotinylated protein targets were purified using immobilised streptavidin beads and identified by MALDI-TOF mass spectrometry. It is anticipated that knowledge of the specific ajoene protein targets will provide valuable insights into the cytotoxic mechanism of action of ajoene in cancer cells.

Citation Format: Catherine H. Kaschula, Daniel A. Kusza, Georgia Schafer, Arieh A. Katz, Shivendra V. Singh, Roger Hunter. Synthesis of a biotin probe for identification of the ajoene protein targets in cancer cells ajoene protein targets in cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5227. doi:10.1158/1538-7445.AM2017-5227
Abstract 523: HGF mediated upregulation of PHLDA2 is associated with apoptosis in gastric cancer
Authors: Koh Sung Ae , Lee Kyung Hee , Kim Jae Ryong , Kim Sang Woon
Published: July 2017

Pleckstrin homology-like domain family A member 2 (PHLDA2), a homolog of the mouse TDAG51 gene, was the first apoptosis-related gene shown to be imprinted and expressed from the maternal allele in normal development. It is located within the tumor suppressor region of 11p15, and its expression was reported to be suppressed in several cases of malignant tumors. But, the apoptotic regulatory mechanism and its role is not fully known in gastric cancer. The purpose of the this study is to identify of function of PHLDA2 associated with apoptosis in gastric cancer.

We used cell culture, western blotting, RT-PCR, MTT assays, PHLDA2 knock-down with short hairpin RNA (shRNA). First, we confirmed that the expression level of PHLDA2 was up-regulated by HGF(hepatocyte growth factor). To identify associated pathway of HGF-induced LCN2, the cells were treated with PI3-kinase inhibitor (LY294002) or MEK inhibitor(PD098059) or p38 inhibitor(SB203580) and then analyzed by Western blotting. The HGF-mediated PHLDA2 protein level was only decreased with LY294002. The role for PHLDA2 with was determined by knock down cell of PHLDA2. PHLDA2-sh RNA cells showed a decreased level of P53 and a increased level of pAKT. We also examined to confirm the role of HGF-mediated PHLDA2. HGF-mediated cell proliferation and in vitro invasion was increased in PHLDA2 knock down cell. Also, HGF-mediated cell apoptosis decreased in PHLDA2 knock down cell.

Our study showed that PHLDA2 upregulated HGF is regulated through PI3K/AKT pathway in gastric cancer, and PHLDA2 have a role in cell apoptosis in gastric cancer, which may be a possible target for developing gastric cancer therapy.

Citation Format: Sung Ae Koh, Kyung Hee Lee, Jae Ryong Kim, Sang Woon Kim. HGF mediated upregulation of PHLDA2 is associated with apoptosis in gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 523. doi:10.1158/1538-7445.AM2017-523
Abstract 5235: Affecting activity of the linear ubiquitin chain assembly complex (LUBAC) with stapled alpha-helical peptides
Authors: Whiting Amanda L. , Aguilar-Alonso Francisco , Mitala Joseph J. , Bernal Federico
Published: July 2017

The linear ubiquitin chain assembly complex (LUBAC) is the only E3 ubiquitin ligase known to generate linear polyubiquitin chains in vitro. LUBAC is composed of three proteins - HOIL-1L, HOIP and SHARPIN - of which the interaction between HOIL-1L and HOIP has been shown to be critical for LUBAC assembly and function. This interaction occurs between the ubiquitin-like (UBL) domain of HOIL-1L and the ubiquitin-associated (UBA) domain of HOIP. One known substrate of LUBAC is the regulatory subunit NEMO (NF kappa B essential modulator), part of the IKK complex, which results in activation of NF-κB. We hypothesize that disruption of the HOIL-1L-HOIP interaction would prevent LUBAC ubiquitylation activity and result in down-regulated activation of NF-κB. We have synthesized a family of small inhibitor peptides designed to mimic aspects of the bent alpha-helical interacting interface of HOIP-UBA. Here we demonstrate how single amino acid substitutions and hydrocarbon stapling can affect overall peptide shape and helicity, and correlate that structural information to peptide binding affinity, ability to affect LUBAC complex formation and resulting effect on LUBAC ubiquitylation activity in vitro. These findings continue to validate inhibition of LUBAC via interference with the HOIL-1L-HOIP interaction as a potential target to affect NF-κB signaling. Compounds which affect LUBAC activity have potential use in LUBAC-dependent NF-κB activation in the activated B cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL), the DLBCL subtype that is most resistant to current therapies.

Citation Format: Amanda L. Whiting, Francisco Aguilar-Alonso, Joseph J. Mitala, Federico Bernal. Affecting activity of the linear ubiquitin chain assembly complex (LUBAC) with stapled alpha-helical peptides [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5235. doi:10.1158/1538-7445.AM2017-5235
Abstract 5237: Targeting DCN1-mediated neddylation in lung SCC with novel small-molecule inhibitors
Authors: Barrios Richard , Hammill Jared , Min Jaeki , Guy Kip
Published: July 2017

Due to the anti-neoplastic properties and clinical successes of the proteasome inhibitors Bortezomib and Carfilzomib, the ubiquitin-proteasome system (UPS) has become a new target of interest in oncology research. The clinical toxicity induced by these inhibitors, likely caused by complete inhibition of the UPS, has resulted in a need for the development of more selective UPS regulators. A more in depth understanding of the intrinsic molecular mechanisms that are associated with the UPS has unmasked the potential for improved therapies via more specific targets such as the process of neddylation, which is thought to control 15 - 20% of the UPS (5). During neddylation, an enzyme known as DCN1 for “defective in cullin neddylation 1” functions as a co-E3 to help steer a ubiquitin-like protein (UBL), NEDD8, from an E2 enzyme, UBC12, to a cullin (CUL) neddylation site (6 - 7, 9 - 11). Because DCN1 has been found to be amplified in certain squamous cell carcinomas (9) (SCCs; e.g. lung, esophagus, and head and neck), this in vitro, pre-clinical study demonstrates the potential of the DCN1-UBC12 interaction as a therapeutic site in lung SCCs through the use of novel small-molecule inhibitors from the St. Jude (SJ) library. After optimizing dosing regimens, it has been determined that re-administering the SJ compounds (i.e. SJ690, SJ447, SJ446, and SJ323) every 24-hours to address the issue of protein turn-over, produces more efficacious treatment. The most biochemically-potent antagonists in the compound series were also shown in these primary cell lines to potentiate other therapeutic agents such as Cisplatin; however, these compounds alone do not induce DNA damage, nor do they elicit caspase 3/7 activity. Nonetheless, combination treatment of the SJ compounds with Staurosporine in SCC cell lines, potentiated caspase 3/7 activity at varying degrees. Collectively, this data enhances our understanding of the mechanism by which the inhibition of DCN1 affects cancer cells, informing pre-clinical development of the SJ DCN1 antagonists.

Citation Format: Richard Barrios, Jared Hammill, Jaeki Min, Kip Guy. Targeting DCN1-mediated neddylation in lung SCC with novel small-molecule inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5237. doi:10.1158/1538-7445.AM2017-5237
Abstract 5240: Induction of molecular endpoints by reactive oxygen species in human lung cells predicted by physical- chemical properties of engineered nanoparticles
Authors: Ross Jeffrey A. , Nelson Garret B. , Jones Carlton , Thai Sheau-Fung
Published: July 2017

A series of six titanium dioxide and two cerium oxide engineered nanomaterials were assessed for their ability to induce cytotoxicity, reactive oxygen species (ROS), and various types of DNA and protein damage in human respiratory BEAS-2B cells exposed in vitro for 72 hours at several concentrations. Although only limited cytotoxicity was observed at concentrations up to 300 µg/ml for all of the nanomaterials, significant increases in 8-oxo-deoxyguanosine, lipid peroxidation mediated protein adducts, and endogenous DNA adducts measured by 32P-postlabeling were detected at concentrations as low as 30 µg/ml, suggesting that molecular changes associated with ROS induction may provide a better means of assessing the low-dose hazards posed by nanomaterials. To identify molecular properties predictive of the ability of nanoparticles to induce ROS sequelae, a least absolute shrinkage and selection operator multiple regression approach has been used to identify relationships between assay outcomes and nanoparticle physical/chemical properties, including particle size, surface area, zeta potential, and elemental analysis. For several of the assay endpoints examined, concentrations of trace metals in the nanoparticles appear to be better predictors of assay outcomes than physical properties. This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.

Citation Format: Jeffrey A. Ross, Garret B. Nelson, Carlton Jones, Sheau-Fung Thai. Induction of molecular endpoints by reactive oxygen species in human lung cells predicted by physical- chemical properties of engineered nanoparticles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5240. doi:10.1158/1538-7445.AM2017-5240