bluuebunny/crossref_metadata_2025 huggingface dataset:
Neural Correlates of Motor Recovery after Robot-Assisted Training in Chronic Stroke: A Multimodal Neuroimaging Study
Authors: Chen Cheng , Yuan Kai , Wang Xin , Khan Ahsan , Chu Winnie Chiu-wing , Tong Raymond Kai-yu
Published: June 2021

Stroke is a leading cause of motor disability worldwide, and robot-assisted therapies have been increasingly applied to facilitate the recovery process. However, the underlying mechanism and induced neuroplasticity change remain partially understood, and few studies have investigated this from a multimodality neuroimaging perspective. The current study adopted BCI-guided robot hand therapy as the training intervention and combined multiple neuroimaging modalities to comprehensively understand the potential association between motor function alteration and various neural correlates. We adopted EEG-informed fMRI technique to understand the functional regions sensitive to training intervention. Additionally, correlation analysis among training effects, nonlinear property change quantified by fractal dimension (FD), and integrity of M1-M1 (M1: primary motor cortex) anatomical connection were performed. EEG-informed fMRI analysis indicated that for iM1 (iM1: ipsilesional M1) regressors, regions with significantly increased partial correlation were mainly located in contralesional parietal, prefrontal, and sensorimotor areas and regions with significantly decreased partial correlation were mainly observed in the ipsilesional supramarginal gyrus and superior temporal gyrus. Pearson’s correlations revealed that the interhemispheric asymmetry change significantly correlated with the training effect as well as the integrity of M1-M1 anatomical connection. In summary, our study suggested that multiple functional brain regions not limited to motor areas were involved during the recovery process from multimodality perspective. The correlation analyses suggested the essential role of interhemispheric interaction in motor rehabilitation. Besides, the underlying structural substrate of the bilateral M1-M1 connection might relate to the interhemispheric change. This study might give some insights in understanding the neuroplasticity induced by the integrated BCI-guided robot hand training intervention and further facilitate the design of therapies for chronic stroke patients.
[Retracted] Marketing Method and System Optimization Based on the Financial Blockchain of the Internet of Things
Authors: Yan Chaosong , Zhu Jun , Ouyang Yinglong , Zeng Xingyu
Published: June 2021

This article makes relevant research and analysis from theory and practice, respectively. At the same time, with reference to the current state of the Internet, relative analysis was used to focus on the state of commercial banks. The analysis mainly focuses on the problems encountered in the current Internet development in various forms such as the bank’s sales status and customer products. In addition, it really made a reasonable opinion about the relevant sales status of this bank. It systematically studied the development history of marketing products of financial blockchain in China’s financial blockchain and analyzed the process of gradual improvement of the functions and characteristics of marketing products of financial blockchain in China. The characteristics and shortcomings of the marketing products of the financial blockchain were discussed in detail, and from the perspective of technological innovation, the application of emerging technologies in the marketing of China’s financial blockchain was analyzed. This article analyzes the many challenges and opportunities faced by security firms in the development of the Internet. Under the new situation, what kind of development model to adopt and how to transform and upgrade is the strategic proposition that security firms must think about. Based on Internet finance, this article finds that the equity crowdfunding model can be selected in the future development of security companies. On the one hand, the use of equity crowdfunding by security firms can enhance their direct financing capabilities, which will benefit the security industry, especially Internet security firms. On the other hand, through equity crowdfunding, security companies can expand direct financing channels for small, medium, and micro enterprises to promote entrepreneurship. The paper promotes the development of Internet finance, thereby improving the ability of the capital market to serve the real economy.
Human Resource Allocation Based on Fuzzy Data Mining Algorithm
Authors: Wu You , Wang Zheng , Wang Shengqi
Published: June 2021

Data mining is currently a frontier research topic in the field of information and database technology. It is recognized as one of the most promising key technologies. Data mining involves multiple technologies, such as mathematical statistics, fuzzy theory, neural networks, and artificial intelligence, with relatively high technical content. The realization is also difficult. In this article, we have studied the basic concepts, processes, and algorithms of association rule mining technology. Aiming at large‐scale database applications, in order to improve the efficiency of data mining, we proposed an incremental association rule mining algorithm based on clustering, that is, using fast clustering. First, the feasibility of realizing performance appraisal data mining is studied; then, the business process needed to realize the information system is analyzed, the business process‐related links and the corresponding data input interface are designed, and then the data process to realize the data processing is designed, including data foundation and database model. Aiming at the high efficiency of large‐scale database mining, database development tools are used to implement the specific system settings and program design of this algorithm. Incorporated into the human resource management system of colleges and universities, they carried out successful association broadcasting, realized visualization, and finally discovered valuable information.
Abstract A05: Context-dependent transformation with activated Ras isoforms in human normal epithelial cells
Authors: Kumazaki Minami , Yamamoto Yusuke
Published: June 2021

The classical mammalian ras genes exist three isoforms K-, H- and N-Ras. Ras mutations are genetic events that have been detected in 30 % of all human cancers. Unfortunately, mutated Ras tumors have not responded to chemotherapy, an IgG1 chimeric monoclonal antibody and tyrosine-kinase inhibitors against EGFR. Therefore, there is need for development of new therapeutic strategies to mutated Ras tumors. Although the function of three Ras isoforms is considered to be almost the same, the occurrence of Ras mutation is largely different in human each tissue. For example, APC and BRACA1 genes are associated with a high risk of developing tissue specific cancer. APC mutation caused familial adenomatous polyposis. Affected people have a nearly 100% lifetime risk of developing colorectal cancer, whereas other tumor types are rare. Such genes are therefore considered as tissue-specific cancer genes. Whether Ras genes have tissue specificity has not been clarified. In this study, we thought to elucidate whether mutated Ras isoform has tissue specificity and there is a difference in the function among three mutated Ras isoforms by using human normal epithelial cell lines (prostate, small airway, mammary, skin and bronchus). In clinical data, skin and bronchus frequently occurred H-Ras mutation, others occurred K-Ras mutation. Firstly, we induced immortalization of these cell lines by introduction of human papillomavirus E6/E7 and mutant c-myc (T58A). These cell lines could stably culture and were expressed cytokeratin 5, which is basal cell marker of epidermis. We analyzed the carcinogenesis efficiency by soft-agar assay when the cells infected with retrovirus of three mutated Ras in five immortalized cell lines. As a result, carcinogenesis efficiency was different for each cell line. These results were mostly consistent with clinical data. Also, we identified downstream signaling of Ras (PI3K-AKT and MAPK signaling) involved in carcinogenesis by performing Western blot analysis when the cells infected with mutated Ras, which induced highest carcinogenesis efficiency in each cell lines. As a result, the protein expression level that associated with growth-related PI3K/AKT and MAPK signaling affected differently in each mutated Ras isoform. These results indicated that mutated Ras isoform have tissue specificity and specific functions involved in carcinogenesis. Taken together, we concluded that these events present the possibility of new therapeutic target for mutated Ras tumors.

Citation Format: Minami Kumazaki, Yusuke Yamamoto. Context-dependent transformation with activated Ras isoforms in human normal epithelial cells [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr A05.
Abstract A13: KRAS4A directly regulates hexokinase 1
Authors: Mahaffety James P. , Amendola Caroline R. , Chen Wei-Ching , Kimmelman Alec , Balmain Allan , Philips Mark R.
Published: June 2021

The KRAS oncogene is alternatively spliced, yielding KRAS4A and KRAS4B, which differ only in their membrane-targeting sequences. Tumors that harbor mutant KRAS manifest enhanced glucose utilization. We report a direct, GTP-dependent interaction between KRAS4A and hexokinase 1 (HK1) that alters the activity of the kinase, establishing HK1 as an effector of KRAS4A. The interaction is unique to KRAS4A because the palmitoylation/depalmitoylation cycle of this RAS isoform permits colocalization with HK1 on the outer mitochondrial membrane. Our findings constitute the first demonstration of direct regulation of a metabolic enzyme by a RAS protein and the first biochemical distinction between the KRAS splice variants. KRAS4A expression in cancer may drive unique metabolic vulnerabilities that can be therapeutically exploited.

Citation Format: James P. Mahaffety, Caroline R. Amendola, Wei-Ching Chen, Alec Kimmelman, Allan Balmain, Mark R. Philips. KRAS4A directly regulates hexokinase 1 [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr A13.
Abstract A15: Axl-mediated activation of TBK1 drives epithelial plasticity in pancreatic cancer
Authors: Cruz Victoria H. , Arner Emily N. , Du Wenting , Bremauntz Alberto E. , Brekken Rolf A.
Published: June 2021

Pancreatic ductal adenocarcinoma (PDA) is characterized by an activating mutation in KRAS, which is critical for the biology of PDA progression. Direct inhibition of KRAS through pharmacologic means remains a challenge; however, targeting key KRAS effectors has therapeutic potential. Higher levels of TANK-binding kinase 1 (TBK1) mRNA, a critical downstream effector of mutant active KRAS, are associated with poorer overall survival in human PDA patients. We report that TBK1 supports the growth and metastasis of KRAS mutant PDA by driving an epithelial plasticity program in tumor cells that enhances invasive and metastatic capacity. Further, we identify that the receptor tyrosine kinase Axl induces TBK1 activity in a Ras-RalB-dependent manner. These findings demonstrate that TBK1 is central to Axl-driven EMT in KRAS mutant PDA and suggest that interruption of the Axl-TBK1 signaling cascade above or below KRAS has potential therapeutic efficacy in this recalcitrant disease.

Citation Format: Victoria H. Cruz, Emily N. Arner, Wenting Du, Alberto E. Bremauntz, Rolf A. Brekken. Axl-mediated activation of TBK1 drives epithelial plasticity in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr A15.
Abstract A29: The gastric cancer-associated mutations R5W and Y42C in the RAS homologous RHOA protein cause distinct biochemical alterations, exhibit gain-of-function signaling and oncogenic activities
Authors: Schaefer Antje , Hodge Richard G. , Blake Devon R. , Zhang Haisheng , Bass Adam J. , Der Channing J.
Published: June 2021

Missense mutations of the RAS homologous RHOA gene have recently been identified in ~25% of diffuse gastric cancer (DGC). Unexpectedly, in contrast to the gain-of-function hotspot mutations found in RAS in cancer, DGC-associated RHOA mutations (e.g., R5W, Y42C) are localized at different hotspots that instead suggest loss-of-function alterations. First, we utilized bacterially expressed recombinant proteins and determined the biochemical consequences of these mutations on RHOA function. We found that RHOA WT and Y42C, but not R5W nucleotide exchange, was catalyzed by the ECT2 RhoGEF. Similarly, WT and Y42C, but not R5W GTP hydrolysis activity, was stimulated by the p190RhoGAP. Surprisingly, Y42C and to a lesser degree R5W exhibited impaired intrinsic GTP hydrolysis activity. Interestingly, Y42C showed both loss- and gain-of-function interaction with effectors. Second, we ectopically expressed WT and mutant RHOA proteins in NIH/3T3 fibroblast, and surprisingly, found that Y42C and R5W, similar to the lab-generated constitutively GTP-bound Q63L mutant (analogous to RAS Q61L), stimulated actin stress fiber formation and focal adhesion assembly. Finally, when ectopically expressed in beta-catenin-deficient (another mutation found in gastric cancer) mouse gastric organoids, Y42C disrupted the 3D architecture and induced a DGC-like phenotype in vitro and in vivo. In summary, our studies suggest mutation-specific biochemical defects that act as gain-of-function oncogenic RHOA mutations.

Citation Format: Antje Schaefer, Richard G. Hodge, Devon R. Blake, Haisheng Zhang, Adam J. Bass, Channing J. Der. The gastric cancer-associated mutations R5W and Y42C in the RAS homologous RHOA protein cause distinct biochemical alterations, exhibit gain-of-function signaling and oncogenic activities [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr A29.
Abstract A44: SHP2 inhibition overcomes RTK-mediated pathway reactivation in KRAS-mutant tumors treated with MEK inhibitors
Authors: Lu Hengyu , Liu Chen , Velazquez Roberto , Wang Hongyun , Dunkl Lukas M. , Kazic-Legueux Malika , Haberkorn Anne , Billy Eric , Manchado Eusebio , Brachmann Saskia M. , Moody Susan , Engelman Jeffrey A. , Hammerman Peter S. , Caponigro Giordano , Mohseni Morvarid , Hao Huai-Xiang
Published: June 2021

FGFR1 was recently shown to be activated as part of a compensatory response to prolonged treatment with MEK inhibitor trametinib in several KRAS-mutant lung and pancreatic cancer cell lines. We hypothesize that other receptor tyrosine kinases (RTKs) are also feedback activated in this context. Herein, we profile a large panel of KRAS-mutant cancer cell lines for the contribution of RTKs to the feedback activation of phospho-MEK following MEK inhibition, using a SHP2 inhibitor (SHP099) that blocks RAS activation mediated by multiple RTKs. We find that RTK-driven feedback activation widely exists in KRAS mutant cancer cells and involves several RTKs including EGFR, FGFR, and MET. We further demonstrate this pathway feedback activation is mediated through mutant KRAS. Finally, SHP099 and MEK inhibitors exhibit combination benefits inhibiting KRAS mutant cancer cell proliferation in vitro and in vivo. These findings provide a rationale for exploration of combining SHP2 and MAPK pathway inhibitors for treating KRAS-mutant cancers in the clinic.

Citation Format: Hengyu Lu, Chen Liu, Roberto Velazquez, Hongyun Wang, Lukas M. Dunkl, Malika Kazic-Legueux, Anne Haberkorn, Eric Billy, Eusebio Manchado, Saskia M. Brachmann, Susan Moody, Jeffrey A. Engelman, Peter S. Hammerman, Giordano Caponigro, Morvarid Mohseni, Huai-Xiang Hao. SHP2 inhibition overcomes RTK-mediated pathway reactivation in KRAS-mutant tumors treated with MEK inhibitors [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr A44.
Abstract A47: Targeting glutaminolysis potentiates the efficacy of chemotherapy in RAS-driven pancreatic cancers
Authors: Mukhopadhyay Suman , Adiseshaiah Pavan , Goswami Debanjan , Nissley Dwight V. , McCormick Frank
Published: June 2021

Pancreatic cancer is an extremely aggressive and deadly malignancy. Despite a detailed understanding of pancreatic ductal adenocarcinoma (PDAC)’s biology, the outcome of the current therapeutic regimen remains grim. Chemotherapeutic treatment is one of the first-line systemic treatments for PDAC. However, creating resistance against chemotherapy remains a major challenge. Oncogenic K-Ras mutation is one of the most common events responsible for the initiation and progression of PDAC. K-Ras mutation also promotes the activation of a transcription factor called NRF2 that is crucial for tumor development and pancreatic cancer proliferation. Our study detects differential basal levels of NRF2 in a panel of PDAC cell lines. We hypothesized that this phenomenon might reflect a greater intrinsic capacity of PDAC cells to become resistant to chemotherapy. We then demonstrated that upregulation of NRF2 creates resistance against chemotherapy in PDAC cells. Consequently, NRF2 activation rewires metabolic pathway networks. Importantly, our metabolomics analysis revealed that, upon NRF2 activation, several metabolic pathways are reprogrammed. Recent advances in tumor metabolism signify the critical role of glutamine as a key regulator of cancer therapy. Moreover, we observed that inhibiting glutamine metabolism enhances the efficacy of chemotherapeutic drugs in PDAC cells. Taken together, our finding holds promise as a novel combination therapy for patients with pancreatic cancer marked by developed resistance against chemotherapy. Finally, this treatment strategy further establishes the potential for exploiting metabolic changes in RAS-driven cancer cells that confer novel therapeutic opportunities.

Citation Format: Suman Mukhopadhyay, Pavan Adiseshaiah, Debanjan Goswami, Dwight V. Nissley, Frank McCormick. Targeting glutaminolysis potentiates the efficacy of chemotherapy in RAS-driven pancreatic cancers [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr A47.
Abstract B04: High-level expression of oncogenic KRAS is required to transform LKB1 mutant tissue in vivo
Authors: Rackley Briana B. , Seong Chang-Soo , Gilbert-Ross Melissa
Published: June 2021

Although activating mutations in the GTPase KRAS are oncogenic and implicated in various malignancies, mutations in KRAS alone are inefficient to transform epithelia. In lung adenocarcinoma, KRAS mutations occur at high frequency and co-segregate with loss of the LKB1 tumor suppressor, a master serine/threonine kinase that phosphorylates and activates multiple AMPK family kinases to control energy homeostasis, cell polarity, and cell:matrix signaling. Despite our current knowledge of LKB1 biology, the complexity of the signaling pathway has precluded investigations into the precise mechanism by which alteration of this kinase contributes to oncogenic transformation and tumor progression in vivo. In the present study, we introduced mutations in Kras and Lkb1 in the genetically tractable organism Drosophila melanogaster. We show that low-level expression of oncogenic Kras (KrasLow) promotes the survival of Lkb1-mutant tissue, eventually leading to a G1 arrest, and concomitant overgrowth of the surrounding tumor microenvironment. Alternatively, high-level expression of oncogenic Kras (KrasHigh) promotes the neoplastic transformation of Lkb1-mutant tissue, leading to autonomous growth and increased cell cycle progression, invasion of mutant tissue into the brain, and the survival and growth of explanted tumor tissue in a wild-type Drosophila host. Interestingly, phosphorylation of the canonical Lkb1 target AMPK is maintained in KrasHigh/Lkb1 neoplastic tissue, but not in KrasLow/Lkb1 tissue. Finally, we analyzed TCGA Pan Lung Cancer data and show that high-level, but not low-level, expression of oncogenic KRAS results in worse overall survival in the context of LKB1 loss. Taken together, these data suggest that increasing levels of oncogenic KRAS, perhaps through mutant KRAS copy gains, are a driving event in the malignant transformation of LKB1-mutant tissue, and that the rewired AMPK signaling axis may offer a potential therapeutic target for patients with this subset of mutations.

Citation Format: Briana B. Rackley, Chang-Soo Seong, Melissa Gilbert-Ross. High-level expression of oncogenic KRAS is required to transform LKB1 mutant tissue in vivo [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr B04.
Abstract B12: DOCK1 as a novel target for controlling RAS-driven cancer cell survival and invasion
Authors: Uruno Takehito , Fukui Yoshinori
Published: June 2021

Oncogenic RAS contributes to malignant phenotypes of cancer cells by stimulating macropinocytosis-dependent nutrient uptake and promoting invasive migration. Because these cellular activities require remodeling of the actin cytoskeleton, which is regulated by the Rho family GTPase Rac, we hypothesized that molecules involved in Rac activation downstream of oncogenic RAS may be valuable targets for cancer therapy. DOCK1 is a Rac-specific guanine nucleotide exchange factor (GEF) implicated in malignancy of breast cancers and glioma. We show that genetic inactivation of endogenous DOCK1 in various RAS-transformed cells markedly suppressed their matrix invasion, macropinocytosis, and survival under glutamine-deprived conditions. We developed a selective inhibitor of DOCK1 that binds to the catalytic domain of DOCK1 and blocks its GEF activity. This inhibitor 1-(2-(3′-(trifluoromethyl)-[1,1′-biphenyl]-4-yl)-2-oxoethyl)-5-pyrrolidinylsulfonyl-2(1H)-pyridone (TBOPP) blocked DOCK1-mediated invasion and macropinocytosis without impairing the immune-regulatory functions of its closely related protein DOCK2. Furthermore, TBOPP treatment suppressed cancer metastasis and growth in vivo in mice. To further assess the role of DOCK1 in RAS-driven cancers, we established the KPC mouse pancreatic ductal adenocarcinoma model bearing DOCK1 conditional knockout allele. Our results demonstrate that targeting DOCK1 could be an effective approach to treat RAS-driven cancers.

Citation Format: Takehito Uruno, Yoshinori Fukui. DOCK1 as a novel target for controlling RAS-driven cancer cell survival and invasion [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr B12.
Abstract B15: Dabrafenib-trametinib-induced pyrexia successfully treated with colchicine
Authors: Vera Jesus , Paludo Jonas , Kottschade Lisa , Block Matthew , Yan Yiyi , Loprinzi Charles , Markovic Svetomir
Published: June 2021

The most common adverse event (AE) of dabrafenib and trametinib (DT) is pyrexia, which has been reported to occur in up to 71% of patients. Pyrexia resulted in therapy discontinuation in up to 26% of patients who otherwise were benefiting from the treatment. Little is known about the pathogenesis and optimal management of this common AE. We hypothesized that the etiology of pyrexia in patients treated with DT could be extrapolated from DT-related cutaneous adverse effects in which a paradoxical MAPK pathway activation has been identified. We hypothesized that the mechanism of MAPK pathway activation with DT therapy is similar to that reported in patients with familial Mediterranean fever (FMF), a rare, inherited condition characterized by episodes of fever and rash that responds exceedingly well to colchicine-based therapy. Based on this association, our group explored the use of oral colchicine for the treatment of DT-associated pyrexia in five patients with metastatic melanoma.

Citation Format: Jesus Vera, Jonas Paludo, Lisa Kottschade, Matthew Block, Yiyi Yan, Charles Loprinzi, Svetomir Markovic. Dabrafenib-trametinib-induced pyrexia successfully treated with colchicine [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr B15.
Abstract B33: Inhibition of Ras using Affimers
Authors: Rao Ajinkya , Haza Kataryzna , Trinh Chi , Edwards Thomas , Tomlinson Darren
Published: June 2021

Ras proteins function as binary switches in order to mediate a wide range of signaling events and are one of the most frequently mutated oncoproteins in human cancers. However, progress in targeting Ras has been slow owing to the lack of obvious druggable sites. Recently, numerous binding proteins have been developed that probe Ras function, which have identified some allosteric sites and have opened new avenues for drug discovery. Affimers are now an established class of binding proteins. They consist of two variable regions that confer molecular recognition with target proteins and molecules. We have isolated Affimers against KRas using phage display. From the phage screen, seven unique binders were isolated and tested in SOScat catalyzed nucleotide exchange reaction to identify inhibitors of nucleotide exchange. Three Affimers, K3, K6 and K37, were the most potent inhibitors of this reaction, with K3 also inhibiting Ras interaction with the Ras binding domain of Raf. To understand the molecular mechanisms of inhibiting both nucleotide exchange and interaction with Raf, the X-ray crystal structure of Affimer K3-KRas complex was solved to 2.1 Å resolution. The Affimer interacts with Switch II region of KRas, causing the α-2 helix region to shift outwards to reveal a hydrophobic pocket that has not been targeted by any other non-antibody binding proteins. It is speculated that the shift in the switch II domain will cause a steric clash with the Ras binding domain of Raf. These results show that Affimers can select for protein conformations not previously identified by other reagents and may aid in further developing Ras binding compounds.

Citation Format: Ajinkya Rao, Kataryzna Haza, Chi Trinh, Thomas Edwards, Darren Tomlinson. Inhibition of Ras using Affimers [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr B33.
Abstract B44: KRAS and RAS signaling network is co-regulated and can be therapeutically blocked by targeting eIF4A dependent translation program
Authors: Singh Kamini , Lin Jianan , Lecomte Nicolas , Mohan Prathibha , Gokce Askan , Sanghvi Viraj , Olivera Grbovic-Huezo , Jiang Man , Burčul Antonija , Stark Stefan , Viale Agnes , Romesser Paul B. , Destanchia Elisa , Bagni Rachel , Rätsch Gunnar , Leach Steve D. , Ouyang Zhengqing , Wendel Hans-Guido
Published: June 2021

New and effective therapeutics are urgently needed for the treatment of pancreatic ductal adenocarcinoma (PDAC). The eIF4A/DDX2 RNA helicase drives translation of mRNAs with highly structured 5′UTRs. The natural compound silvestrol and synthetic analogues are potent and selective inhibitors of eIF4A1/2 that show promising activity in models of hematologic malignancies. Here, we show silvestrol analogues have nanomolar activity against PDAC cell lines and organoids in vitro. Moreover, we see single-agent activity in the KRAS/p53 mouse PDAC model and also against PDAC xenograft and primary, patient-derived PDAC tumors. These therapeutic effects occur at nontoxic dose levels. Transcriptome-wide ribosome profiling, analyses of protein and gene expression, and translation reporter studies reveal that KRAS and the RAS signaling network is co-regulated by translation in an eIF4A dependent manner. eIF4A inhibitors block an oncogenic translation program in PDAC cells that includes G-quadruplex containing mRNAs such as KRAS, MYC, YAP1, MET, SMAD3, TGFβ and other components of the RAS signaling network. Together, our data indicate that pharmacologic inhibition of eIF4A disrupts oncoproteins production and shows efficacy across several PDAC models.

Citation Format: Kamini Singh, Jianan Lin, Nicolas Lecomte, Prathibha Mohan, Askan Gokce, Viraj Sanghvi, Grbovic-Huezo Olivera, Man Jiang, Antonija Burčul, Stefan Stark, Agnes Viale, Paul B. Romesser, Elisa Destanchia, Rachel Bagni, Gunnar Rätsch, Steve D. Leach, Zhengqing Ouyang, Hans-Guido Wendel. KRAS and RAS signaling network is co-regulated and can be therapeutically blocked by targeting eIF4A dependent translation program [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr B44.
Abstract IA03: KRAS Q61H preferentially signals through the MAPK pathway in non-small cell lung cancer
Authors: Zhou Zhiwei , Ambrogio Chiara , Bera Asim , Qing Li , Cheng-Xiong Xu , Janne Pasi , Westover Ken
Published: June 2021

RAS proteins are guanosine triphosphatases (GTPases) that function as binary switches cycling between inactive (GDP-bound) and active (GTP-bound) states. Activated RAS proteins bind RAS effectors including RAF kinases, PI3K, RalGDS, and others. Conversion from GDP to GTP is stimulated by guanine nucleotide exchange factors (GEFs) while conversion to the inactive GDP-bound form is mediated by GTPase activating proteins (GAPs). Mutations can alter the signaling properties of RAS proteins through a number of means including modification of the GTPase activity, nucleotide exchange rate, or effector binding characteristics. Understanding these differences may enable new therapeutic approaches to specific RAS mutations associated with human disease. We will discuss how codon 61 mutations in KRAS can result in profoundly reduced intrinsic and GAP-stimulated GTPase activity, and a relatively high affinity for RAF-RBD compared to other oncogenic KRAS mutations, and how these features may enable therapeutic options for cancers bearing RAS mutations at codon 61.

Citation Format: Zhiwei Zhou, Chiara Ambrogio, Asim Bera, Li Qing, Xu Cheng-Xiong, Pasi Janne, Ken Westover. KRAS Q61H preferentially signals through the MAPK pathway in non-small cell lung cancer [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr IA03.
Abstract IA06: Oncogenic Ras control of the tumor immune microenvironment
Authors: Downward Julian
Published: June 2021

Despite RAS proteins being exceptionally well-validated cancer targets, little progress has been made towards targeting them effectively in the clinic. We have optimized combination targeting of effector pathways downstream of RAS for specific activity on KRAS mutant cells, with combinations targeting MEK, IGF-1R and mTORC1 being highly effective in preclinical models. Replacing MEK with G12C KRAS inhibitor reduces the toxicity of the combination. However, these combinations are not able to eradicate tumors, which recur once treatment is stopped. In order to improve the effectiveness of RAS-targeted therapies, we have investigated the mechanisms whereby RAS signaling pathways can promote local immune suppression in the tumor microenvironment through inducing the expression of immune checkpoint proteins, immune suppressive cytokines, and extracellular enzymes. One such pathway involves the control of mRNA stability of PD-L1 and multiple cytokines by the 3′AU rich element binding protein, tristetraprolin. Another pathway that appears to be strongly upregulated in RAS mutant tumors is signaling by extracellular adenosine, which is strongly immunosuppressive. In order to test potential combinations of targeted therapies and immunotherapies resulting from these studies, we have developed new mouse models for KRAS mutant lung cancer that show more realistic interaction of the immune system with the tumor, which is not seen in existing genetically engineered mouse models used to study RAS mutant cancer due their lack of tumor heterogeneity and mutational burden. This work also involves detailed analysis of the tumor immune microenvironment using imaging mass cytometry and comparison between manipulatable mouse models and human clinical samples from the TRACERx lung cancer study.

Citation Format: Julian Downward. Oncogenic Ras control of the tumor immune microenvironment [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr IA06.
Abstract IA23: Developing therapies for Ras-driven cancers
Authors: Cichowski Karen
Published: June 2021

While selective kinase inhibitors have changed the standard of care in cancers that are driven by oncogenic kinases, there are currently few treatment options for malignancies that lack a “targetable” oncogenic driver. Ras-driven cancers are particularly problematic: agents that target individual Ras effector pathways are largely ineffective and successful therapeutic combinations have not yet been identified. Therefore, it is imperative that we rationally conceptualize and test new therapeutic combinations that either 1) function to suppress orthogonal pathways in tumors, 2) converge on specific cancer cell vulnerabilities, and/or 3) exploit multiple therapeutic modalities. In this presentation various combinatorial strategies designed to inhibit Ras effector kinases and other targets will be discussed. By dissecting the mechanism by which promising combinations are working in preclinical models, we have uncovered nodal points of convergence between these distinct pathways and have identified new vulnerabilities that can be targeted in Ras-driven tumors.

Citation Format: Karen Cichowski. Developing therapies for Ras-driven cancers [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr IA23.
Abstract IA24: Oncogenic Ras-dependent tumor cell vulnerabilities
Authors: Bar-Sagi Dafna
Published: June 2021

A longstanding goal of the work in my lab has been to identify strategies by which the oncogenic potential of mutant Ras can be compromised. The overall framework for our efforts is based on the wealth of evidence indicating that the robustness of the transformed phenotype that is displayed by cells that harbor oncogenic Ras reflects the engagement of a unique set of biologic processes that are critical for tumor initiation and progression. Because by definition these processes represent tumor cell-specific vulnerabilities, our working premise has been that knowledge of the mechanisms downstream of oncogenic Ras that control these processes could be leveraged to develop tumor-specific targeting modalities. We have been testing this premise in the context of Ras-dependent processes that control metabolic adaptation, immune evasion, stress resistance, and proliferative capacity. Recent observations and lessons learned will be discussed.

Citation Format: Dafna Bar-Sagi. Oncogenic Ras-dependent tumor cell vulnerabilities [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr IA24.
Abstract IA32: Interplay between RAF inhibitors and RAS
Authors: Zhang Ying , Bollag Gideon
Published: June 2021

Ever since RAF was shown to be a key downstream effector of RAS in the early 90s, RAF inhibition has been a goal within the drug discovery community. Sorafenib, an early entrant to the RAF armamentarium, was discovered through biochemical RAF inhibition assays with the goal of disrupting RAS signaling. Anticancer efficacy that was demonstrated through clinical trials was likely through “off-target” inhibition of VEGF receptors, and RAF is not effectively inhibited in RAS-mutant tumor cells. Furthermore, BRAF-mutant tumors were also poorly targeted by sorafenib, most likely because the “type 2” binding mode is ineffective against the activated BRAF kinase. Subsequently, compounds such as vemurafenib, dabrafenib, and encorafenib were developed as “type 1” inhibitors that target the active form of BRAF kinase: these inhibitors show efficacy in many BRAF-mutant tumors. Curiously, these RAF inhibitors cause certain side effects that have been attributed to the “RAF inhibitor paradox”: the ERK pathway is paradoxically stimulated by RAF inhibitors in cells with an activated RAS pathway. To overcome this liability, the next generation of RAF inhibitors dubbed “paradox breakers” were developed. As a BRAF-specific dimer disruptor, PLX8394 selectively inhibits ERK signaling in tumors bearing both monomer- and dimer-dependent BRAF mutants, including BRAF fusions and splice variants, while sparing RAF function in normal cells and avoiding paradoxical ERK activation in RAS-mutant cells. A converse effort seeks to take advantage of the paradox to identify RAS cell liabilities. By hyperstimulating the ERK pathway, “paradox activators” could tip the balance in favor of cellular disharmony. Future efforts exploiting this mechanism will enhance the context for thinking about RAF and near-neighbor targets in RAS tumors and guide the judicious selection of combination therapies involving RAF-targeting agents and other therapeutics.

Citation Format: Ying Zhang, Gideon Bollag. Interplay between RAF inhibitors and RAS [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr IA32.
Abstract PR06: Combinations with CDK4/6 inhibitors to treat cancers with mutations in both KRAS and CDKN2A
Authors: Litchfield Lacey , Kapoor Avnish , Wu Wenjuan , Gong Xueqian , Webster Yue , Peng Sheng-Bin , Bhagwat Shripad , Merzoug Farhana , Buchanan Sean G.
Published: June 2021

Oncogenic KRAS mutations commonly co-occur with loss of CDKN2A in pancreas and lung cancer. Both mutations are known to activate D-cyclin dependent kinases and therefore may confer sensitivity to drugs that inhibit CDK4 and CDK6 (CDK4/6i). Indeed, preclinical studies have shown that KRAS/CDKN2A double-mutant cancers are reasonably sensitive to CDK4/6 inhibitors and the CDK4/6i abemaciclib showed evidence of benefit in clinical studies of KRAS-mutant NSCLC (1) (http://www.ascopost.com/News/58135). However, despite the encouraging result, abemaciclib did not meet a prespecified overall survival endpoint in the JUNIPER trial, and it has been shown that failure to suppress CDK2 activity diminishes the antiproliferative activity of CDK4/6i in KRAS/CDKN2A mutant cancer cells (2). Since CDK2-specific inhibitors are not available for clinical combination strategies, it is unclear how to exploit this discovery. We employed CRISPR and shRNA genome-wide library screens to identify alternate mechanisms to potentiate the CDK4/6 inhibitor abemaciclib in this class of cancer. Depletion of Src family or Ras-MAPK pathway genes emerged as consistent hits in both lung and pancreas cancer cells with KRAS/CDKN2A mutations. Inhibitors of Src family or Ras-MAPK pathway kinases led to a strong suppression of CDK2 activity and apoptosis when combined with abemaciclib. Across a panel of cancer cell lines, ERKi LY3214996 combined with abemaciclib potently inhibited the growth of KRAS/CDKN2A mutant cancer cells. The combination of LY3214996 with abemaciclib was well tolerated in vivo and caused regressions in mice bearing human KRAS/CDKN2A mutant tumor xenografts, supporting the clinical examination of this drug combination.

References

1. Patnaik A et al. Efficacy and safety of abemaciclib, an inhibitor of CDK4 and CDK6, for patients with breast cancer, non-small cell lung cancer, and other solid tumors. Cancer Discov 2016;6:740-53.

2. Gong X et al. Genomic aberrations that activate D-type cyclins are associated with enhanced sensitivity to the CDK4 and CDK6 inhibitor abemaciclib. Cancer Cell 2017;32:761-76 e766.

This abstract is also being presented as Poster A33.

Citation Format: Lacey Litchfield, Avnish Kapoor, Wenjuan Wu, Xueqian Gong, Yue Webster, Sheng-Bin Peng, Shripad Bhagwat, Farhana Merzoug, Sean G. Buchanan. Combinations with CDK4/6 inhibitors to treat cancers with mutations in both KRAS and CDKN2A [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr PR06.
Abstract AP12: FOXM1 INDUCES DNA REPLICATION STRESS AND PROMOTES GENOMIC INSTABILITY DOWNSTREAM OF CYCLIN E1 IN HIGH-GRADE SEROUS OVARIAN CANCER
Authors: Barger Carter J , Biswas Kajal , Chee Linda , Drapkin Ronny , Sharan Shyam , Karpf Adam R.
Published: June 2021

PURPOSE: Genomic instability (GI) is a hallmark of high-grade serous ovarian cancer (HGSC), and induction of the FOXM1 transcription factor regulatory network is the second most frequent genetic alteration in HGSC. FOXM1 expression is associated with cancer GI, but the mechanistic link is unknown. DNA replication stress (DRS), which involves altered replication fork dynamics, is a key contributor to cancer GI. FOXM1 and cyclin E1 (CCNE1) are both expressed in STIC lesions in the fallopian tube epithelium (FTE), and CCNE1-CDK2 enhances FOXM1 transcriptional activity. Based on these observations, we hypothesized that: 1) FOXM1 is linked to cancer GI through the induction of DRS, and 2) FOXM1 promotes GI downstream of CCNE1, by promoting unscheduled M phase entry in cells that have not completed DNA synthesis.

METHODS: We determined associations between FOXM1 and markers of DRS and GI in TCGA HGSC data. We overexpressed FOXM1c and a DNA binding domain mutant (DBD) in immortalized FTE cells and characterized the impact on DRS, DNA replication, and DNA damage. We determined the impact of CCNE1 on FOXM1 expression in immortalized FTE cells. We determined the combined effect of CCNE1 and FOXM1 on GI in FTE cells.

RESULTS: FOXM1 was significantly associated with markers of DRS (CHK1-Ser345) and GI (fractional copy number altered genome (CNA)) in TCGA HGSC data. FOXM1 expression, but not its DBD mutant, induced biomarkers of DRS and DNA damage in hTERT/mutant Tp53 immortalized FTE cells. Unexpectedly, FOXM1c increased DNA replication fork rate in FTE cells. Increased fork rate is a novel and recently recognized cause of DRS. CCNE1 expression in FTE cells induced and activated FOXM1, promoting mitotic entry. FOXM1 and CCNE1 co-expression in FTE cells induced an expression signature of GI, and TCGA HGSC tumors with FOXM1 and CCNE1 co-expression showed significantly increased GI.

CONCLUSIONS: We demonstrate that FOXM1 induces DRS and DNA damage in FTE cells, providing an explanation for the known link between FOXM1 and GI. Notably, FOXM1 induces a novel form of DRS involving increased replication fork rate. We show that CCNE1 activates FOXM1, which in turn promotes mitotic entry and GI. These data reveal a potentially major form of oncogenic collaboration in HGSC, and has implications for HGSC treatment approaches that promote DRS or inhibit the cellular DRS response.

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Citation Format: Carter J Barger, Kajal Biswas, Linda Chee, Ronny Drapkin, Shyam Sharan, Adam R. Karpf. FOXM1 INDUCES DNA REPLICATION STRESS AND PROMOTES GENOMIC INSTABILITY DOWNSTREAM OF CYCLIN E1 IN HIGH-GRADE SEROUS OVARIAN CANCER [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr AP12.
Abstract AP17: MOLECULAR AND FUNCTIONAL HETEROGENEITY OF CANCER ASSOCIATED FIBROBLASTS IN HIGH-GRADE SEROUS OVARIAN CANCER
Authors: Hussain Ali , Voisin Veronique , Poon Stephanie , Meens Jalna , Dmytryshyn Julia , Paterson Josh , Bernardini Marcus , Bader Gary , Neel Benjamin G , Ailles Laurie E
Published: June 2021

High grade serous ovarian cancer (HGSC) is typically diagnosed at an advanced stage and the vast majority of patients relapse and die within 5 years of diagnosis. Significant clinical problems in HGSC include wide-spread abdominal dissemination of disease and chemotherapy resistance. Cancer-associated fibroblasts (CAFs) have been shown to play a role in promotion of cancer cell proliferation and invasion, and mediation of chemotherapy resistance. To interrogate the molecular properties of CAFs in HGSC we used fluorescence activated cell sorting to isolate CAFs directly from primary tumor samples and performed gene expression profiling. We found that patients stratify into two classes based on their CAF gene signatures: One with high expression of Fibroblast Activation Protein (FAP-High; FH) and one with low expression of FAP (FAP-Low; FL). FH CAFs express classical CAF genes whereas FL CAFs possesses a preadipocyte-like molecular signature. The FL phenotype has remained largely unnoticed as it is generally out-competed in vitro by FH cells when grown under classical CAF culture conditions. Patients from The Cancer Genome Atlas (TCGA), as well as from our own institute, can be stratified into FH and FL subtypes; in both cohorts patients with FH CAFs have a significantly shorter disease-free and overall survival. In vitro and in vivo functional assays performed with isolated CAFs of both types indicate that FH CAFs aggressively promote proliferation, invasion and therapy resistance of cancer cells, whereas FL CAFs do not. Finally, we identified TCF21, a transcriptional repressor, as a FL-specific transcription factor. Analysis of published TCF21 ChIP-Seq data indicates that TCF21 targets a large number of genes specific to FH CAFs. Overexpression of TCF21 in FH CAFs partially reversed their ability to promote cancer cell invasion and tumor growth. Our discovery of CAF heterogeneity in HGSC highlights the need to personalize patient treatment with respect to both cancer and stromal phenotypes. FH patients may benefit from inhibition of cancer-stroma interactions or from epigenetic modulators that reprogram cancer-promoting FH CAFs into the non-supportive FL state.

Citation Format: Ali Hussain, Veronique Voisin, Stephanie Poon, Jalna Meens, Julia Dmytryshyn, Josh Paterson, Marcus Bernardini3, Gary Bader, Benjamin G Neel, Laurie E Ailles. MOLECULAR AND FUNCTIONAL HETEROGENEITY OF CANCER ASSOCIATED FIBROBLASTS IN HIGH-GRADE SEROUS OVARIAN CANCER [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr AP17.