bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2085: Treatment of human melanoma cells with dasatinib requires inactivation of both mTOR and MAPK pathways to achieve high cell eradication efficacy
Authors: Vachtenheim Jiri , Réda Jiri , Vlčková Kateřina , Ondrušová Lubica 
Published: August 2019

Abstract
Advanced stages of melanoma are resilient to therapy and new strategies for the treatment are required. About 60% of melanomas harbor the mutated BRAF oncogene, which activate the MAPK pathway. This BRAF driver mutation can be targeted by a small molecule drug vemurafenib. However, most of patients develop resistance during treatment and even drug addiction is acquired. The nonreceptor SRC tyrosine kinase is highly expressed and deregulated in melanoma and can be efficiently inhibited by the inhibitor dasatinib, an anticancer drug which is already used for the treatment of some tumor types. SRC does not have its own canonical pathway but is capable of activating and augmenting different signaling routes in cancer cells. We found that melanoma tumor cell lines analysed were generally resistant to dasatinib irrespective of BRAF or NRAS mutational status. The exception was the cell line Hbl which was very sensitive even to low dasatinib doses and Hbl cells were completely eradicated by 10 nM of dasatinib in several days. The sensitivity of Hbl to dasatinib was dependent on the drug ability to inhibit completely both the MAPK and AKT/mTOR signaling pathways. Dasatinib was capable of inhibiting SRC activation resulting in the repression of AKT activation in Hbl cells. AKT phosphorylation at Ser473 was fully abolished and Thr308 was severely attenuated through inhibiting SRC by dasatinib in Hbl cells. These two phosphorylations are required for AKT activity. MAPK pathway (ERK1/2 phosphorylation) was also inhibited in Hbl cells. Dasatinib also inhibited the phosphorylation of SRC at Tyr416 (a hallmark of SRC activity) in Hbl cells and, surprisingly, also in other dasatinib-resistant melanoma cells. Importantly, although SRC was dephosphorylated at Tyr416, dasatinib was unable to inactivate AKT and MAPK pathway (ERK1/2) in all other melanoma cells. Molecular changes closely correlated with proliferation assays. Our data indicate that the combination therapy of melanoma with dasatinib would bring benefit to patients only by blocking both MAPK and AKT signaling pathways in melanoma cells. Altogether, more molecular knowledge of the effects of the powerful anticancer drug dasatinib is required in order to be used for the treatment of melanoma. This work was supported by the Institutional research project PROGRESQ25 from Charles University Prague.
Citation Format: Jiri Vachtenheim, Jiri Réda, Kateřina Vlčková, Lubica Ondrušová. Treatment of human melanoma cells with dasatinib requires inactivation of both mTOR and MAPK pathways to achieve high cell eradication efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2085.
Abstract 2093: Drug induced autophagy and transcriptional gene expression signatures in breast cancer cell lines
Authors: Mascia Francesca , Karagiannis Kostantinos , Wu Wells W. , Shen Rong-Fong , Rao Ashutosh 
Published: August 2019

Abstract
Cancer cells can bypass the desired cell death response to chemotherapy through cytoprotective autophagy. In support of this hypothesis, drug resistant clones display higher basal autophagy than the correspondent drug sensitive cell lines. Autophagy therefore represents a potential target to reduce drug resistance and to enhance drug efficacy. We induced autophagy in several breast cancer cell lines with differing ER/PR/Her2 status by exposing them to tamoxifen (MCF-7/ER positive cells), trastuzumab (SKBR3/Her2 positive cells), bortezomib and rapamycin (MDA-MB-231 triple negative cells) in the presence and absence of an autophagy inhibitor such as hydroxychloroquine. While the ongoing autophagy flux process was confirmed by the amount of LC3II at the lipidated protein level, total RNA was extracted at the same time to perform RNA sequencing analysis. We performed differential expression analysis between all the drug treatments and the relative basal level of each cell type obtaining a cell and drug-specific gene list. We then compared all the gene lists to find a common, cell and drug-independent signature. Bioinformatic analysis was performed using the software IPA (Ingenuity Pathway Analysis) and setting a threshold of 0.01 for the p value. This analysis suggested a set of canonical pathways that are significantly and commonly affected in all the samples tested. The top canonical pathways disrupted in all the gene sets were the one identified as tRNA charging, CHK proteins in cell cycle check point control, hypoxia signaling and unfolded protein response. We plan to further identify the smallest gene list that is associated with the disruption of all these pathways across all the cells. This signature may help to uncover a consistent biomarker of autophagy that can be used during preclinical and clinical drug development aiming to reduce or eliminate drug resistance and improve cancer treatment outcomes.
Citation Format: Francesca Mascia, Kostantinos Karagiannis, Wells W. Wu, Rong-Fong Shen, Ashutosh Rao. Drug induced autophagy and transcriptional gene expression signatures in breast cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2093.
Abstract 2110: WEE1 inhibition could reverse trastuzumab resistance by downregulation of PD-L1 in HER2-positive cancers
Authors: Jin Meihua , Nam Ah-Rong , Park Ji-Eun , Bang Ju-Hee , Oh Kyoung-Seok , Oh Do-Youn , Bang Yung-Jue 
Published: August 2019

Abstract
Background: Trastuzumab in combination with chemotherapy is a standard of care for patients with HER2-positive breast and gastric cancer. Resistance mechanism to trastuzumab, anti-HER2 therapy, includes multiple pathways. Cancer cells could evade immune surveillance through high expression of programmed cell death ligand 1 (PD-L1) on cancer or immune cells. Among resistance mechanisms to trastuzumab, the role of PD-L1 modulation has not yet been discovered in HER2-positive cancers. WEE1 is involved in cell cycle progression and DNA damage response (DDR), and, interestingly, beyond DDR, it could modulate immunes.
We aimed to evaluate the role of PD-L1 in trastuzumab resistance in HER2-positive cancers with/without immune cells and to explore WEE1 inhibitor as a trastuzumab resistance overcoming strategy by modulation of PD-L1.
Methods: Four trastuzumab-resistant (HR) cells (SNU216HR, N87HR, SNU2670HR, SNU2773HR) were established from 2 HER2-amplified gastric cancer cells (SNU216, NCI-N87) and 2 HER2-amplified biliary tract cancer cells (SNU2670, SNU2773). For WEE1 inhibition, AZD1775 was used. MTT assay, colony formation assay, cell cycle analysis by FACS Calibur flow cytometer, and western blot were done.
Results: All four HR cells showed PD-L1 upregulation compared with parental cells. When PD-L1 was knocked-down by transfection with si-PD-L1, anti-growth/proliferation effects were observed in MTT assay and colony forming assay. PD-L1 itself may promote cancer cell growth without interacting with immune cells.
AZD1775 downregulated PD-L1 expression and induced cell cycle arrest at sub-G1 and G2/M phases in all 4 HR cells. The synergistic anti-proliferative effects were found in all 4 HR cells with co-treatment of trastuzumab and AZD1775.
Conclusion: PD-L1 upregulation may contribute to trastuzumab resistance in HER2-positive cancer cells. Targeting WEE1-PD-L1 pathway might be a candidate strategy to overcome trastuzumab resistance in HER2-positive cancers.
Citation Format: Meihua Jin, Ah-Rong Nam, Ji-Eun Park, Ju-Hee Bang, Kyoung-Seok Oh, Do-Youn Oh, Yung-Jue Bang. WEE1 inhibition could reverse trastuzumab resistance by downregulation of PD-L1 in HER2-positive cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2110.
Abstract 2114: Co-delivery nanoparticle to overcome therapeutic resistance in human head and neck cancer promoted by insufficient Src-targeted treatment
Authors: Lang Liwei , Shay Chloe , Wang Xuli , Teng Yong 
Published: August 2019

Abstract
Head and neck cancer (HNC) exhibiting resistance to molecular-targeted therapeutics poses a challenge to their effective clinical management and alternative treatment strategies are actively sought to improve results. Src is commonly hyperactivated in HNC cells and has been implicated as an oncogenic driver in the development and progression of HNC. Unfortunately, the clinical benefit is dampened significantly in HNC patients because only a small fraction of patients respond positively to Src-targeted treatment, and many develop drug resistance. Here, we demonstrate that the addition of AKT blockade in Src-targeted treatment may prevent activation of alternative signaling pathways to bypass the Src inhibition in HNC cells. The combination of Src and AKT inhibitors significantly suppressed HNC growth more efficiently than either drug alone. However, the properties and pharmacokinetics of two inhibitors required a novel approach to optimal delivery into the same tumor cells. To address this, we developed novel tumor-targeting nanoparticles to selectively co-deliver Src and AKT inhibitors to the tumor site in an orthotopic mouse model of HNC. This nanotherapeutic modality significantly improved the efficacy of tumor repression, which was mainly attributed to the highly specific tumor-targeted drug delivery system and synergistic anticancer effect by co-inactivation of AKT and Src. The results of this study will enable us to take a major step toward addressing the urgent need for single drug resistance and failure, and strongly impact on the development of clinically acceptable therapeutics to combat HNC.
Citation Format: Liwei Lang, Chloe Shay, Xuli Wang, Yong Teng. Co-delivery nanoparticle to overcome therapeutic resistance in human head and neck cancer promoted by insufficient Src-targeted treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2114.
Abstract 2117: Different sensitivities of four protein tyrosine kinase inhibitors towards drug-resistant RET mutations
Authors: Liu Xuan , Shen Tao , Huang Qingling , Peng Teng , Hilberg Frank , Cai Jianfeng , Mooers Blaine H. , Wu Jie 
Published: August 2019

Abstract
The RET protein tyrosine kinase (PTK) is a clinically validated target of therapy in non-small cell lung cancer (NSCLC) and thyroid cancer. Mutations in the targeted PTKs is a mechanism of drug resistance in cancer therapy with tyrosine kinase inhibitors (TKIs). Mutation-sensitive secondary drugs have been used successfully to overcome acquired drug-resistance to the first line TKIs. Cabozantinib, lenvatinib, vandetanib, and nintedanib are FDA-approved multikinase TKIs with anti-RET activity. Using RET kinase-dependent BaF3/KIF5B-RET cells, we isolated thirteen mutations resistant to one of these TKIs. Cross-analysis of sensitivities of these four TKIs on these drug-resistant RET mutants and the RETM918T mutant, which is found in medullary thyroid carcinoma, revealed different TKI resistance-sensitivity profiles. In particular, the RETM918T mutant was resistant to cabozantinib, lenvatinib, and vandetanib but did not affect the potency of nintedanib. RETL881V was isolated as a vandetanib-resistant mutation. The RETL881V mutation also induced resistance to cabozantinib and lenvatinib but did not affect the nintedanib sensitivity. Examination of the RET-vandetanib co-crystal structure and the chemical structures of vandetanib and nintedanib suggested that a phenyl group in nintedanib, which corresponds to a methoxy group in vandetanib, may form hydrophobic interaction with the shorter side chain of Val881 and thus allows nintedanib to inhibit RETL881V. To test this possibility, we synthesized two nintedanib analogs (Compound 1 and Compound 2) without the phenyl group and tested their activities. The data showed that RETL881V was resistant to Compound 1 and Compound 2, supporting a role of the phenyl group of nintedanib in mediating inhibition of RETL881V. Taken together, we have identified 13 RET mutations that display different resistance-sensitivity profiles against four anti-RET TKIs. Moreover, nintedanib is effective in inhibiting RETM918T and RETL881V mutants that are resistant to the other three TKIs.
Citation Format: Xuan Liu, Tao Shen, Qingling Huang, Teng Peng, Frank Hilberg, Jianfeng Cai, Blaine H. Mooers, Jie Wu. Different sensitivities of four protein tyrosine kinase inhibitors towards drug-resistant RET mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2117.
Abstract 2141: Mechanistic studies of altertoxin II: A fungal metabolite with selective activity against Ewing sarcoma
Authors: Robles Andrew J. , Dai Wentao , Cichewicz Robert H. , Mooberry Susan L. , Houghton Peter J. 
Published: August 2019

Abstract
Ewing sarcomas (ES) are bone and soft tissue tumors that affect children and adolescents. These cancers are driven by chromosomal translocations that most frequently result in expression of the abnormal EWSR1-FLI1 fusion protein, a transcriptional activator and modulator of RNA splicing, or similar fusion proteins. Despite significant advances in therapies for pediatric hematological malignancies over the past 30 years, there has been less progress in the development of curative therapies for advanced or metastatic pediatric solid tumors. Approximately 35% of ES are resistant to standard-of-care chemotherapeutic agents, and nearly 70% of ES patients with metastatic disease at the time of diagnosis die within 5 years. Therefore, there is a need to develop new, targeted therapies for ES that improve patient survival and decrease toxicity. We performed high-content phenotypic screens of natural product libraries to identify compounds with selective actions against pediatric solid tumor types and found that the fungal metabolite altertoxin II (ATXII) has highly selective cytotoxic activity against 6 ES cells lines compared to a panel of other pediatric and adult cancer cell lines. On average, the IC50 of ATXII is 94-fold higher (range 16- to 400-fold) in rhabdomyosarcoma (RMS) cells than in ES cells, indicating high selectivity for ES. Mechanistic studies were conducted to determine this compound’s mechanisms of actions in ES cells, with the goal of identifying new molecular targets for the treatment of ES. We found that 100 nM ATXII, a concentration that has no effect on RMS cell viability, induces cell cycle accumulation in ES cells in the S and G2/M phases, and rapid phosphorylation of histone H2A.X (gamma-H2A.X) and checkpoint kinase 1, suggesting ATXII selectively induces cell cycle arrest and DNA damage in ES cells. To determine if ES sensitivity to ATXII is a dominant or recessive phenotype, we hybridized sensitive EW8 cells (ES) with resistant Rh30 cells (RMS) and determined the sensitivity of these hybrids to ATXII. Five single-cell subclones derived from these hybrids were resistant to ATXII, suggesting that sensitivity to ATXII is a recessive phenotype in ES cells. Ongoing studies are aimed at determining the cellular uptake and binding kinetics of radiolabeled ATXII and identifying genes that mediate sensitivity and resistance to this compound by performing a genome-wide CRISPR/Cas9 knockout screen.
Citation Format: Andrew J. Robles, Wentao Dai, Robert H. Cichewicz, Susan L. Mooberry, Peter J. Houghton. Mechanistic studies of altertoxin II: A fungal metabolite with selective activity against Ewing sarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2141.
Abstract 2157: Eliminating Edge Effect in 96-Well Plates by Controlling Thermal Conditions during Cell Plating
Authors: Darou Shannon , Henn Alicia , Alm Kersti , Frank Allayna M. , Yerden Randy 
Published: August 2019

Abstract
The traditional approach to avoiding the increased variability in 96-well plate edge wells has been to avoid using them. This results in a 37% loss in usable assay space, increasing time and materials needed for cell-based assays. Approaches to reducing this “edge effect” have included reducing plate evaporation during long-term incubation. However, we have preliminary data that plating cells at a constant 37 degrees C dramatically reduces edge effect. We have previously showed that in plates filled at room temp (RT), the cells in edge and corner wells experienced the most directional cell rolling during cell settling, preventing random cell deposition. In contrast, cells plated at 37 degrees C settled randomly in edge wells with less or no directional rolling. Here, we extend these findings with studies of well-specific cell settling patterns associated with plate-wide thermal changes after cell plating. Our null hypothesis was that intra-well thermal currents as plates warm to 37 degrees C from RT do not disrupt random cell deposition during settling. A549 human lung carcinoma cells were plated in warmed medium in either traditional uncontrolled RT conditions or in an Xvivo System under completely controllable conditions. In this closed chamber, everything (chamber floor, atmosphere, the pipettor, tips, fluids, gloves, and plate) was at the same temp as the incubator, where cells typically settle in the wells after plating. We used the PHI HoloMonitor M4 microscope to record holographic time-lapse images of cells settling and adhering to the well floor. Crystal violet staining was used to assess cell deposition patterns. We found that not only did constant temp conditions change well-specific cell settling patterns, but when plate-wide thermal changes were inverted, by plating cells at 37 degrees C and letting them settle at RT, we were able to alter well-specific cell rolling and cell settling patterns. We concluded that it is thermal changes that drive edge well variability and that constant temperature control during cell plating can reduce or eliminate edge effect. Plating cells under full-time control of conditions could have a tremendous impact on cell-based drug discovery and pre-clinical testing by allowing full use of 96-well plates. This could reduce assay time and materials as well as improve assay reproducibility.
Citation Format: Shannon Darou, Alicia Henn, Kersti Alm, Allayna M. Frank, Randy Yerden. Eliminating Edge Effect in 96-Well Plates by Controlling Thermal Conditions during Cell Plating [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2157.
Abstract 2178: Targeted delivery of chemotherapeutic agents employing nanovesicles effectively reduced intrahepatic tumors
Authors: George Joseph , Hayashi Nobuhiko , Saito Takashi , Tsutsumi Mikihiro , Tsuchishima Mutsumi 
Published: August 2019

Abstract
Background and Aims: Currently there is no appropriate method for effective and targeted delivery of chemotherapeutic agents to tumor sites. The conventional chemotherapy is afflicted with lack of effective drug delivery to the tumor site, unwanted injury to actively dividing healthy cells, and numerous side effects due to toxicity. The present study was aimed to develop a biologically derived nanoparticle based drug delivery system for the effective treatment of primary hepatic tumors.
Methods: Intrahepatic tumors were induced in immunosuppressed mice using PLC/PRF/5 hepatocellular carcinoma (HCC) cells stably transfected with a mammalian expression vector carrying luciferase gene for in-vivo imaging. Nanovesicles ranging from 80-150 nm were isolated from bovine skim milk using ultracentrifugation and characterized using nanoparticle tracking analysis (NTA) and electron microscopy. Purified nanovesicles were loaded with chemotherapeutic agents and antisense oligonucleotides for grossly deregulated microRNAs specific to HCC. Animals with uniform intrahepatic tumors were injected with nanovesicle loaded anticancer agents through tail vein. Tumor regression was monitored weekly using in-vivo imaging system and the animals were maintained up to 8 weeks.
Results: Bioluminescence based in-vivo imaging demonstrated significant reduction of tumor size in treated animals compared to untreated controls. There was increased survival rate and complete absence of metastasis in all treated animals. Untreated mice developed large intrahepatic tumors, which also metastasized to other organs. There were no side effects or immunological reactions in animals injected with plain nanovesicles without loading of any anticancer agents.
Conclusions: The present study demonstrated that milk derived nanovesicles can be effectively used for successful delivery of anticancer agents into intrahepatic tumors. Nanovesicle based targeted drug delivery system could be an effecient method for the treatment of primary hepatic tumors.* Presenting author E-mail: georgej@kanazawa-med.ac.jp
Note: This abstract was not presented at the meeting.
Citation Format: Joseph George, Nobuhiko Hayashi, Takashi Saito, Mikihiro Tsutsumi, Mutsumi Tsuchishima. Targeted delivery of chemotherapeutic agents employing nanovesicles effectively reduced intrahepatic tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2178.