bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5326: Targeted extracellular vesicle to deliver combined chemotherapies to treat cancers
Authors: Chen Kai , Si Yingnan , Kim Seulhee , Zhou Zhuoxin , Zhou Lufang , Liu X. Margaret
Published: June 2022

Extracellular vesicles (EV), facilitated with cancer-targeted antibody or peptide, have been demonstrated as an effective delivery vehicle of chemotherapy and gene therapy. This study aimed to develop and evaluate a targeted EV to deliver a newly identified natural cytotoxic marine compound verrucarin A (Ver-A) or combination with highly potent microtubule polymerization inhibitor mertansine (DM1). The tumor models, glioblastoma (GBM), triple-negative breast cancer (TNBC) and others, were used to validate the developed targeted therapy. First, the stirred-tank bioreactor-based EV biomanufacturing was optimized by developing a two-step purification procedure using size exclusion (300 kDa) and affinity (CD63) columns in liquid chromatography system. Second, both single and dual tumor-targeting monoclonal antibodies (mAbs), such as anti-SSTR2, CD276, EGFR and/or CD47 mAb either developed in house or used in clinics, were tagged on the surface of PEGylated EV to construct mAb-EV-drugs. The flow cytometry analysis, live-cell confocal images and IC50 assay revealed the effective surface binding, intracellular drug delivery and high anti-cancer cytotoxicity of mAb-EV-drugs in cancer cell lines, and the biodistribution study confirmed the tumor targeting in xenograft mouse models. Furthermore, the maximum tolerated dose study showed minimal systemic toxicity, as confirmed by hematoxylin and eosin staining of multiple important organs. Finally, the anti-tumor efficacy study demonstrated significant inhibition of tumor growth by mAb-EV-Ver-A or Ver-A/DM1 in cell line-derived xenograft models, patient-derived xenograft models, and/or immunocompetent xenograft models. This study suggested that the targeted EV is an efficient platform to deliver combined potent chemotherapies to treat cancer or tumor.

Citation Format: Kai Chen, Yingnan Si, Seulhee Kim, Zhuoxin Zhou, Lufang Zhou, X. Margaret Liu. Targeted extracellular vesicle to deliver combined chemotherapies to treat cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5326.
Abstract 534: An ultrasensitive high-plex assay detecting 24 PIK3CA mutations using SAGAsafe® technology and 6-color Crystal Digital PCR™
Authors: Alcaide Miguel , George Anthony M. , Chen Yilun , Jovelet Cécile , Kilani Sahbi Ben , Saal Lao H. , Mallory Allison C.
Published: June 2022

Starting from a minimally invasive liquid biopsy sample such as a blood sample, one can determine genetic and biological properties of cancer by measuring circulating tumor DNA (ctDNA). ctDNA measurements require a highly sensitive and reliable detection technology to quantify often low-level genetic aberrations within a high background of wild-type sequences.

The focus of this study was to demonstrate the performance of the patented SAGAsafe digital PCR chemistry using 6-color Crystal Digital PCR, by adapting a SAGAsafe assay for a clinically relevant oncogene, PIK3CA. PIK3CA encodes the p110-alpha kinase and is the target of a recently approved drug, alpelisib, for metastatic breast cancer. By combining the power of the SAGAsafe technology with that of 6-color Crystal Digital PCR on the naica system®, we present a highly multiplexed, ultrasensitive proof-of-concept PIK3CA detection assay capable of detecting and quantifying 24 PIK3CA mutations in a single digital PCR reaction.

By evaluating the sensitivity, specificity and precision of the high-plex 6-color PIK3CA digital PCR assay, we show that despite the complexity of the assay, the data were extremely clean resulting in highly accurate quantifications down to mutant allele frequencies (MAFs) in the 0.01% range. In addition, superb PIK3CA mutation detection specificity and sensitivity were observed with Limits of Blank ranging from 0.003% to <0.001% MAF, and Limits of Detection ranging from 0.009% to 0.002% MAF in a high background of wild-type DNA. Moreover, a high concordance was observed between Crystal Digital PCR PIK3CA results and NGS data on breast cancer biopsies.

By joining 6-color Crystal Digital PCR and ultrasensitive SAGAsafe technology, high sensitivity and specificity can be maintained even in a complex multiplex digital PCR assay. This proof-of-concept assay sets the stage for the future development of ultrasensitive, highly multiplexed cancer detection panels to achieve better patient stratification and monitoring during therapy.

Citation Format: Miguel Alcaide, Anthony M. George, Yilun Chen, Cécile Jovelet, Sahbi Ben Kilani, Lao H. Saal, Allison C. Mallory. An ultrasensitive high-plex assay detecting 24 PIK3CA mutations using SAGAsafe® technology and 6-color Crystal Digital PCR™ [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 534.
Abstract 5348: SEMA3C signaling confers resistance to Wnt Inhibition in glioblastoma
Authors: Hao Jing
Published: June 2022

Background: Wnt signaling is widely dysregulated in cancer. The therapeutic potential of Wnt inhibitors appears promising in preclinical studies. However, they have uniformly failed clinical trials. How cancer cells develop Wnt inhibitor resistance is poorly understood. Current Wnt inhibitors are designed targeting either ligand or receptor. We hypothesized cancer cells will bypass ligand-receptor interaction through an unknown mechanism. We focused on the neurodevelopmental signaling program of Semaphorin 3C (Sema3C) that is upregulated in 85% of GBM and regulates glioma stem-cell-driven tumor progression.

Methods: We analyzed the expression of Sema3C and TCF1 expression pattern in 32 human GBM samples by immunohistochemistry. GSC self-renewal was assessed by extreme limiting dilution, Edu incorporation, tumorsphere formation and cell survival assays in Sema3C silencing GSCs. Cell fractionation and immunofluorescence studies were performed to assess β-catenin sub-cellular localization in GSCs. GSC-derived mouse models were assessed for survival.

Results: Porcupine inhibitor LGK974 reduced TCF1 expression in the GBM tumor mouse models, suggesting successful target engagement in vivo. However, it failed to prolong the overall survival. Sema3C expression strongly correlated with TCF1 expression in human GBM samples by immunohistochemical analysis. Genetic inhibition of Sema3C and TCF1 together prolonged animal survival more than either alone, indicating better control of Wnt pathway signaling with dual pathway blockade. Immunofluorescence and cell fractionation studies revealed that Sema3C signaling drove β-catenin nuclear accumulation. Sema3C regulates transactivation of Wnt target genes including TCF1, c-Myc and c-Met. Sema3C pathway activates Rac1. It is reported that Rac1 activates β-catenin and promotes β-catenin nuclear accumulation. In GSCs, constitutively active Rac1 restored β-catenin nuclear localization and rescued TCF1 and c-Myc down-regulation in the setting of Sema3C silencing. Sema3C can drive canonical Wnt signaling even when Wnt ligand secretion is blocked. Together, the data support that GSCs can escape Wnt inhibition through Sema3C and Rac1.

Conclusions: Sema3C signaling drives canonical Wnt signaling, providing an escape mechanism for cancer cells despite Wnt ligand-receptor interruption. Sema3C-β-catenin signaling promotes GSC self-renewal and tumor progression. Upstream Wnt pathway inhibition alone is insufficient to control tumors. Our data provide a therapeutic strategy of dual blockade of Wnt and Sema3C pathways to provide clinically significant tumor control.

Citation Format: Jing Hao. SEMA3C signaling confers resistance to Wnt Inhibition in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5348.
Abstract 5349: Single-cell analysis sheds light on the resistance mechanisms of a novel pan-HER inhibitor, pyrotinib, in non-small cell lung cancer
Authors: Wang Xinfeng , Li Yuan , Jin Runsen , Sun Nan , He Jie
Published: June 2022

Recently, a novel oral, irreversible pan-HER tyrosine kinase inhibitor, pyrotinib, has shown anticancer effects on HER2-mutant non-small cell lung cancer (NSCLC) patients, but the explicit responses of lung cancer cells towards pyrotinib treatment are barely investigated. In our current study, we employed single-cell RNA sequencing to profile the longitudinal transcriptomic dynamics of lung cancer cells during the pyrotinib treatment, unraveling the potential resistance mechanisms. We treated a lung adenocarcinoma cell line, H358, with pyrotinib at doses of 100nM, 200nM, 500nM, and 1000nM every four days, respectively. Then, the untreated cells (P0) as well as longitudinal samples after each administration (P4, P8, P12, P16) were harvested for further analysis. After quality control, a total of 41,804 cells were sequenced and included for further analysis. The differentially expressed genes were determined using MAST and the differentially enriched cancer hallmark signatures based on single-sample Gene Set Variation Analysis (ssGSVA) were identified. The single-cell data revealed that the untreated cells (Sample P0) and persistent cells (Sample P16) had stable and distinct gene expression patterns, while cells during the course of treatment shared similar expression features at a transitional state. Several cancer driver genes were found to be aberrantly regulated during the administration, like EPHA2, CDKN2A, CDK4, PTEN, and MYC. Also, some pathways related to immune response were suppressed after pyrotinib treatment, including interferon alpha response, interferon gamma response, TNFA signaling via NF-κB, and inflammatory response. Intriguingly, CD274 (the gene encoding PD-L1) and LGALS9 were found to significantly decrease after pyrotinib treatment, suggesting that pyrotinib may be associated with outcomes of immunotherapy. With the large cell numbers analyzed, we distinguished an isolated, small subpopulation of cells characterized by the enriched expression of MGP, COL1A1, COL1A2, SPARC, and COL3A1 along with the elevated EMT and angiogenesis scores, suggesting its critical role in pyrotinib resistance. Collectively, our study for the first time reveals the transcriptomic evolution of NSCLC cells in response to pyrotinib administration at the single-cell resolution, providing new insights into potential mechanisms of resistance to this novel regimen in NSCLC.

Citation Format: Xinfeng Wang, Yuan Li, Runsen Jin, Nan Sun, Jie He. Single-cell analysis sheds light on the resistance mechanisms of a novel pan-HER inhibitor, pyrotinib, in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5349.
Abstract 5359: M6A regulated NNMT mediates resistance to platinum in ovarian cancer
Authors: Huang Hao , Zhao Guangyuan , Valdivia Andres Felipe , Cardenas Horacio , Wang Yinu , Matei Daniela Daniela
Published: June 2022

Background: Ovarian cancer (OC) remains one of the deadliest malignancies. Development of resistance to platinum (Pt) is a major clinical problem and understanding its underpinnings will help find new approaches to overcome it. Fat mass and obesity associated protein (FTO) is a N6-methyladenosine (m6A) demethylase and plays an important role regulating how the messenger RNA is processed translating into functional proteins. We recently showed that m6A modifications induced by FTO play a suppressive role in tumorigenicity and survival of OC stem cells. Here we hypothesized that RNA modifications caused by FTO regulate the response of OC cells to Pt.

Methods: To study the mechanisms related to FTO implicated in response to Pt; we used OC cells in which FTO was knocked down (KD) via shRNA or overexpressed (OE). Additionally, Pt-resistant (Pt-R) OC cells were obtained through repeated (3-4) exposures to Pt. Cell viability assay determined the IC50 (half maximal inhibitory concentration) to Pt. Pt response in vivo was assessed in FTO expressing vs. FTO KD xenografts. Induction of DNA damage was assessed by immunofluorescence (IF) for γ-H2AX. Apoptosis was evaluated by Annexin V staining in the IncuCyte system. To identify potential targets of FTO-mediated m6A modifications in Pt induced response, RNA-seq and MeRIP-seq were integrated.

Results: FTO was significantly downregulated in Pt-R vs. sensitive OC cells. Forced expression of FTO increased sensitivity to Pt in vitro and in vivo, while FTO KD increased Pt resistance (p<0.05). A catalytic mutant FTO did not appreciably alter responsiveness to Pt. Increased γ-H2AX foci and increased apoptosis were observed after exposure to Pt in FTO OE vs. control cells. Through integrated RNA-seq and MeRIP-seq, we identified and validated several potential targets involved in response to Pt including IER5, IER5, ST3Gal, and the enzyme nicotinamide N-methyltransferase (NNMT). NNMT was upregulated and significantly hypomethylated in FTO OE cells and was downregulated in Pt resistant cells. Treatment with an NNMT inhibitor rescued the FTO induced sensitivity to Pt in OC cells demonstrating that its function is necessary in the response to Pt.

Conclusions: We identified a new function of FTO-dependent m6A RNA modifications in regulating response to Pt through NNMT, a novel RNA methylated target. Activating FTO could improve response to Pt in OC.

Citation Format: Hao Huang, Guangyuan Zhao, Andres Felipe Valdivia, Horacio Cardenas, Yinu Wang, Daniela Daniela Matei. M6A regulated NNMT mediates resistance to platinum in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5359.
Abstract 5364: The TEAD autopalmitoylation inhibitor VT3989 improves efficacy and increases durability of efficacy of osimertinib in preclinical EGFR mutant tumor models
Authors: Tang Tracy T. , Post Leonard
Published: June 2022

The Hippo-YAP/TAZ pathway is involved in the regulation of cell proliferation, survival, and cell migration. The major effectors of the Hippo pathway are the TEAD transcription factors, which become transcriptionally activated upon YAP/TAZ binding. Genetic alterations of pathway components have been reported in a variety of human malignancies, resulting in YAP/TAZ constitutive nuclear localization and TEAD activation. The TEAD transcription factors have been shown to autopalmitoylate, and palmitoylation is required for its interaction with YAP/TAZ and hence activation of transcriptional activity. We have identified potent, selective, and orally available small molecule compounds that directly interact with TEAD and block its autopalmitoylation (Tang et al, 2021, Mol Cancer Ther. 20(6):986-998). These TEAD inhibitors disrupt YAP/TAZ-TEAD protein interaction, suppress TEAD transcriptional activity, and selectively block proliferation of NF2-deficient mesothelioma in vitro and inhibit NF2 mutant xenograft tumor growth in vivo. Nuclear YAP accumulation and functional requirement have also been linked to resistance to targeted therapies and cancer relapse in BRAF-mutant, KRAS-mutant, EGFR-mutant, and ALK-rearranged non-small cell lung cancers (NSCLC). Hence, as TEAD transcription factors are the main drivers for YAP/TAZ recruitment to chromatin, we evaluated the effect of our TEAD inhibitor VT3989, currently in clinical testing, on emerging drug tolerant persistent cancer cells and drug resistance during EGFR-tyrosine kinase inhibitor osimertinib treatment in combination studies. In in vitro cell proliferation assays, VT3989 showed strong to very strong synergy in combination with osimertinib in several EGFR mutant NSCLC cell lines tested. In vivo, we observed strong VT3989 and osimertinib combination effect in NCI-H1975 and HCC827 cell line-derived xenograft models. We also tested the combination in several EGFR mutant NSCLC patient-derived xenograft models and demonstrated that the addition of VT3989 enhanced the efficacy of osimertinib and delayed tumor regrowth compared to osimertinib alone.

Citation Format: Tracy T. Tang, Leonard Post. The TEAD autopalmitoylation inhibitor VT3989 improves efficacy and increases durability of efficacy of osimertinib in preclinical EGFR mutant tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5364.
Abstract 5366: Hotspot mutations of TP53 sensitize APC-mutated colorectal cancer cells to cetuximab in vitro
Authors: Yang Mingli , Wang Heiman , Davis Thomas B. , Pflieger Lance , Thota Ramya , Pledger W. Jack , Yeatman Timothy J.
Published: June 2022

EGFR inhibitor (EGFRi) therapies (cetuximab and panitumumab) have been approved for metastatic CRC patients who harbor wild-type KRAS/NRAS. Unfortunately, only ~50% of treated patients will respond to therapy. While FDA approved for first-line therapy, these agents are seldom used, significantly limiting their utility. Thus, there is an unmet need to develop additional biomarkers to identify EGFRi sensitive patients. Using an innovative hybrid approach fusing gene expression and DNA sequencing, we recently reported that combined mutations in APC and TP53, two major tumor suppressor genes, were strongly correlated with a validated gene expression signature measuring cetuximab sensitivity (CTX-S) in 468 CRC human tumors (Yang et al. Cancer Epidemiol Biomarkers Prev. 2019). Further analysis reported that APC and TP53 mutations predict cetuximab sensitivity across consensus molecular subtypes (CMS1-4) (Thota et al. Cancers. 2021). While APC truncated mutations are known to mediate WNT pathway activation, one of key features of CMS2 CRCs reported to be associated with cetuximab response, little is known about TP53 mutations with cetuximab sensitivity. To investigate a contributive role of mutant TP53 in vitro, we stably transfected expression plasmids of three hotspot mutations (R175H, R248W, R273H) of TP53 in APC-mutated CRC cells such as SW48 cells harboring WT KRAS/NRAS. Multiple stable clones for each of three TP53 mutations (empty vector as a control) were selected for biochemical and RNASeq analyses. We found that the three oncogenic mutations of TP53 enhanced cetuximab-mediated apoptosis under low serum culture conditions (2% FBS). Interestingly, the enhanced drug effect was associated with altered p53 pathway signatures as assessed by RNASeq. In support of the role of TP53 mutations, siRNA-knockdown of TP53 in SW48 cells also demonstrated an increased sensitivity to cetuximab treatments. Collectively, these in vitro analysis supports TP53 mutations, in combination with APC mutations, as predictive mutation biomarkers of cetuximab sensitivity in CRC.

Citation Format: Mingli Yang, Heiman Wang, Thomas B. Davis, Lance Pflieger, Ramya Thota, W. Jack Pledger, Timothy J. Yeatman. Hotspot mutations of TP53 sensitize APC-mutated colorectal cancer cells to cetuximab in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5366.
Abstract 5428: Evaluating cancer therapies combining radiotherapy with immunotherapy or inhibitors of the DNA damage response
Authors: Fan Feifei
Published: June 2022

Ionizing radiation has largely been recognized as a local targeted therapy by a variety of mechanisms, including inducing direct DNA damage of cancerous tissue or contributing to systemic antitumor immunity. The capacity of cancer cells to recognize DNA damages and initiate repair plays a major role in radio-resistance. Furthermore, the irradiated tumor cell death can enhance antitumor immunity by inducing antigen expression on tumor cells and activating lymphocytes. Recent evidence indicates that cancer cells can be made more sensitive to the effects of radiation (radio-sensitization) through inhibition of DNA repair pathways, and a growing body of evidence indicates that cancer immunotherapy may also have radio-sensitizing effects. The combination of radiation therapy and DDR inhibitors/immunotherapy presents a promising strategy for cancer therapy.In order to provide guidance on clinical therapeutic strategy selection, we established a beam-focused radiation platform (RadSource 2000 X-ray irradiator) to evaluate the anti-tumor efficacy of fractionated radiotherapy combination in a panel of cell lines and mouse models. We have tested the combination effect of DDR inhibitor in combination with radiotherapy in vitro and in vivo, both showing radio-sensitization effects and improvement in anti-tumor activity. We have also chosen several syngeneic models to test the combination strategy of radiotherapy and immune checkpoint inhibitors (PD-1 and PD-L1), and performed TIL analysis to explore the possible mechanisms of combination effect. In summary, our beam-focused radiation platform provides insights into the design of new therapeutic strategies and has become an effective tool in pre-clinical research of anti-cancer therapy.

Citation Format: Feifei Fan. Evaluating cancer therapies combining radiotherapy with immunotherapy or inhibitors of the DNA damage response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5428.
Abstract 544: Role of an ankyrin domain protein in hepatocellular carcinoma progression
Authors: Lopez Samantha , Anilkumar Adithya , Doxtater Kyle , Kotnala Sudhir , Chauhan Neeraj , Yallapu Murali , Jaggi Meena , Chauhan Subhash , Tripathi Manish
Published: June 2022

Background: Liver cancer is the third leading cause of mortality attributed to cancer. Hepatocellular carcinoma (HCC) is the most prevalent form among various histological types accounting for 85% to 90% of primary liver cancers. As per Texas Cancer Registry, the Hispanic population had an incidence of 21.2 per 100,000 in Texas. The Rio Grande Valley, located in South Texas, is an underserved area composed highly of Hispanics. It faces multiple disparities that can attribute to increased risk factors of HCC and, thus, a higher liver cancer incidence and mortality. Due to this, there is a need to identify a new, inexpensive, and faster diagnostic biomarker in liver cancer. We have recently identified an extracellular secreted cancer antigen POTE-2, a member of the ankyrin domain-containing POTE gene family. Our preliminary data indicates high POTE-2 expression in HCC tumors. In this study, we will discuss the role of POTE-2 in HCC progression and its associated regulatory pathways.

Methods: The Cancer Genome Atlas (TCGA) database of HCC patients (n=371 tumor; n=50 normal) was analyzed. Liver cancer cell lines procured from ATCC were analyzed for POTE-2 mRNA and protein expression through RT-PCR and western blot, respectively. Lentiviral-based plasmids were used for overexpression and knockdown studies for oncogenic assays. Localization of POTE-2, YAP1, and PDL1 was identified with immunofluorescence.

Results: Comprehensive analysis of the TCGA database showed increased POTE-2 expression in tumors and is upregulated in all stages of HCC. Lentiviral transduction led to a change in phenotype in oncogenic assays. Modulation of POTE-2 expression led to changes in kinase activity and regulatory pathways. Immunofluorescence showed nuclear localization of YAP1 and PDL1 in the liver cancer cell lines.

Conclusion: These studies will help discover novel mechanisms of POTE-2 protein function, signaling pathways, and its role in liver cancer progression.

Citation Format: Samantha Lopez, Adithya Anilkumar, Kyle Doxtater, Sudhir Kotnala, Neeraj Chauhan, Murali Yallapu, Meena Jaggi, Subhash Chauhan, Manish Tripathi. Role of an ankyrin domain protein in hepatocellular carcinoma progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 544.
Abstract 5441: Discovery of a novel RAD51 inhibitor SCR-6992 targeting homologous recombination pathways in cancer
Authors: Gu Peng , Xue Liting , Chen Ping , Li Wenjing , Geng Ya , Zhou Feng , Yang Guimei , Hou Xiaohong , Zhao Chunyan , Yang Wenqing , Tang Renhong
Published: June 2022

Targeting DNA damage response (DDR) pathways has been proposed as an approach for amplifying tumor-specific replicative lesions. RAD51 plays a central role in the DDR pathway, and thus represents a promising anti-tumor target. We here report the discovery of a series of next generation RAD51 inhibitors that can prevent RAD51 foci formation and particularly, a pre-clinical candidate molecule SCR-6992 with potent anti-tumor efficacies and desirable pre-clinical development drug properties. SCR-6992 exhibits remarkable anti-proliferative potency in human lymphoma Daudi cells in vitro (IC50 = 12 nM) while has no inhibitory effect in normal human cells. The combination of SCR-6992 with chemotherapeutic agents or DDR-targeting drugs produces synergistical anti-cancer response in lymphoma and solid tumor cell lines. Furthermore, SCR-6992 significantly inhibits tumor growth in Daudi xenograft tumor model with the tumor regression observed when dosed orally at 80 mg/kg/day. SCR-6992 also shows acceptable translational drug properties and pharmacokinetic profiles in both rodents and dogs. SCR-6992 was well tolerated in rats and dogs in 14-day dose range finding studies without noted hematological or gastrointestinal toxicities, when dosed up to 200 mg/kg and 40 mg/kg, respectively. Taken together, SCR-6992 demonstrates as an effective RAD51 inhibitor with encouraging anti-tumor activities and favorable development drug properties. The clinical development plans of SCR-6992 have been formulated for hematologic malignancies and solid tumors.

Citation Format: Peng Gu, Liting Xue, Ping Chen, Wenjing Li, Ya Geng, Feng Zhou, Guimei Yang, Xiaohong Hou, Chunyan Zhao, Wenqing Yang, Renhong Tang. Discovery of a novel RAD51 inhibitor SCR-6992 targeting homologous recombination pathways in cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5441.
Abstract 5444: BPI-371153, an orally bioavailable small molecule PD-L1 inhibitor
Authors: Wang Yiqian , Jing Xiangyan , Chen Hong , Zhang Huijuan , Ma Tianyi , Zhang Yao , Zhang Chunhui , Zhang Guangzhi , Liu Xiangyong , Yan Dan , Guo Jing , Lan Hong , Wang Jiabing , Ding Lieming
Published: June 2022

PD-1/PD-L1 antibodies have entered mainstream of cancer treatment, but they came with limitations such as weak tumor penetration, immunogenicity, immune-related risks with a long half-life, and high cost. Small molecule inhibitors of PD-L1 are expected to overcome these limitations. We hereby present BPI-371153, an orally bioavailable small molecule that disrupts PD-1/PD-L1 interaction similar to PD-1/PD-L1 antibodies. BPI-371153 demonstrates high binding affinity to human PD-L1, induces PD-L1 dimeralization and disrupts PD-L1:PD-1 interaction (IC50 <1 nM by HTRF assay). BPI-371153 induces PD-L1 internalization with an IC50 value of 4.2 nM as detected by flow cytometry, activates nuclear factor of activated T cell (NFAT) signaling in cell-based reporter assay, and effectively stimulates IFN-γ release in human peripheral blood monocyte-mediated tumor cell killing assay. In a syngeneic mouse model with murine MC38 colon tumor cells expressing human PD-L1 (MC38-hPD-L1 model), BPI-371153 suppressed tumor growth to an extent comparable to an anti-PD-L1 antibody. In immunocompromised mice grafted with the same cell line, no growth inhibition was observed, confirming that the pharmacologic effect of BPI-371153 indeed came from the immune system. In addition, this compound exhibits favorable ADME properties, with high oral exposure across multiple pre-clinical species. Phase I clinical trial of BPI-371153 is planned for early 2022.

Citation Format: Yiqian Wang, Xiangyan Jing, Hong Chen, Huijuan Zhang, Tianyi Ma, Yao Zhang, Chunhui Zhang, Guangzhi Zhang, Xiangyong Liu, Dan Yan, Jing Guo, Hong Lan, Jiabing Wang, Lieming Ding. BPI-371153, an orally bioavailable small molecule PD-L1 inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5444.
Abstract 5474: A new class of histone deacetylase inhibitors alleviate breast cancer cells growth and invasion capacity by targeting TIMP/MMP signaling
Authors: Bajbouj Khuloud , Sahnoon Lina , AL-Ali Abeer , Shafarin Jasmin , Binder Leonie , Rehman Reem Abdul , El-Awady Rafat , Al-Tel Taleb H.
Published: June 2022

Background: Mounting epidemiological and experimental evidences strongly suggest that epigenetic processes including histone modifications are involved in the development of drug resistance in breast cancer. Histone deacetylases (HDACs) selective inhibition is an important strategy of anticancer drug discovery field. However, lack of HDACs isozymes selective inhibitors associated with adverse side effects that limits their clinical applications. We have recently reported new and selective HDACs inhibitors displaying varying HDAC isozyme selectivity degrees that resulted in increased histones acetylation and apoptosis induction in cancer cells. In the present study, we investigated molecular mechanisms underlying anticancer potential of these molecules in breast cancer cells. Experimental methods: Proliferation ability, invasion capacity, matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMP) major group’s gene expressions and protein levels, and the gelatinolytic activity of MMPs were analyzed after treatment of MCF-7 and MDA-MB-231 breast cancer cell lines with HDACs inhibitors compounds.

Results and Discussions: Two compounds, identified as MAL-4 and MAL-5, were selected based on the half-maximal inhibitory concentration (IC50) in both breast cancer cells. Treatment of MCF-7 and MDA-MB-231 breast cancer cells with 5 µM MAL-4 and MAL-5 significantly induces TIMP-2 mRNA and protein levels whereas MMP-2 and MMP-9 content and activities were reduced. Further analyses showed that MAL-4 and MAL-5 attenuated invasion capability of breast cancer cells.

Conclusion: We have demonstrated that the new compounds can be used as potential lead drug candidates for an effective anti-metastatic therapy mediated by HDAC inhibition in breast cancer.

Citation Format: Khuloud Bajbouj, Lina Sahnoon, Abeer AL-Ali, Jasmin Shafarin, Leonie Binder, Reem Abdul Rehman, Rafat El-Awady, Taleb H. Al-Tel. A new class of histone deacetylase inhibitors alleviate breast cancer cells growth and invasion capacity by targeting TIMP/MMP signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5474.
Abstract 5476: Novel azetidine-based STAT3 inhibitors induce misfolded protein response, endoplasmic reticulum stress and mitophagy, and inhibit breast tumor growth in vivo
Authors: Yue Peibin , Lopez-Tapia Francisco , Zhu Yinsong , Verma Nagendra , Alonso-Valenteen Felix , Mikhael Simoun , Medina-Kauwe Lali , Tius Marcus , Turkson James
Published: June 2022

Anticancer drugs that directly target Signal Transducer and Activator of Transcription (Stat)3 have remained elusive. We present azetidine-based small molecules as a new class of potent Stat3 inhibitors. Compounds H172 and H182 have potency (IC50) of 0.38-0.98 µM, H105 and H120 have IC50 of 1.75-2.07 µM against Stat3 DNA-binding activity in vitro, compared to the IC50 of >17 µM against Stat1 or Stat5 activity. Treatment of the triple-negative breast cancer (TNBC), MDA-MB-231 and MDA-MB-468 cells with the new compounds inhibited constitutive Stat3 activation, promoted Stat3 ubiquitination, blocked anchorage-dependent and independent growth, with potency, EC50 of 1.0-1.9 μM, and induced apoptosis of these cells. By contrast, pYStat1, pYStat5, pS727Stat3, pSrc, pJanus kinase, or the induction of other signaling events are not inhibited in compound-treated cells, and normal or tumor cells that do not harbor aberrantly-active Stat3 are only weakly inhibited. In vivo delivery of H120 or H182 as a single agent inhibited growth of human TNBC xenografts, and of H278 (HCl salt of H182) combined with radiation abrogated tumor growth and improved survival in mouse TNBC syngeneic models. These studies provide novel mechanism of disruption of aberrantly-active Stat3 and its dynamics in showing that the azetidine-based Stat3 inhibitors trigger Stat3 ubiquitination, and tumor cell death. H182 and H172 are new entities for further therapeutic development against TNBC and other cancers that harbor aberrantly-active Stat3.

Citation Format: Peibin Yue, Francisco Lopez-Tapia, Yinsong Zhu, Nagendra Verma, Felix Alonso-Valenteen, Simoun Mikhael, Lali Medina-Kauwe, Marcus Tius, James Turkson. Novel azetidine-based STAT3 inhibitors induce misfolded protein response, endoplasmic reticulum stress and mitophagy, and inhibit breast tumor growth in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5476.
Abstract 5499: Efficacy of icotinib as adjuvant therapy for patients with stage IIA-IIIA EGFR-mutant non-small-cell lung adenocarcinoma: a multicenter, open-label, single-arm, phase II study (ICAPE)
Authors: Qian Kun , Hu Bin , He Ming , Wang Zi-Tong , Liu Yu , Liang Hua-Gang , Su Zhi-Yong , Cui Yu-Shang , Liu Li-Jun , Zhang Yi
Published: June 2022

Background: Currently, epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) have been proved to significantly improve the clinical outcome of patients with EGFR-mutant non-small-cell lung cancer (NSCLC). Icotinib is an oral, reversible and selective first-generation EGFR-TKI. The survival benefits of 1-year and 2-year adjuvant icotinib in patients with EGFR-mutant NSCLC have been confirmed in previous studies. However, the optimal duration of adjuvant icotinib remains unknown. This study (ICAPE) evaluated the efficacy of 1.5-year adjuvant therapy with icotinib for patients with stage IIA-IIIA EGFR-mutant non-small-cell lung adenocarcinoma.

Methods: Patients with stage IIA-IIIA EGFR-mutant non-small-cell lung adenocarcinoma were enrolled in the multicenter, open-label, single-arm, phase II study. Eligible patients received oral icotinib 125 mg thrice daily for 1.5 years after complete surgical resection. Primary endpoint was disease-free survival (DFS). Secondary endpoints included 1-year, 3-year, as well as 5-year OS rates, and the DFS according to the BIM mutation status (mutant-type and wild-type) and EGFR mutation types (19 del and 21 L858R).

Results: Between March 2014 and January 2018, 79 patients were enrolled. The median follow-up time was 39.7 months with a median DFS and overall survival (OS) of 41.4 months (95% CI: 33.6-51.8) and 67.0 months (95% CI: 21.2-not reached [NR]), respectively. The 1-year, 3-year and 5-year OS rates were 100%, 83.3%, and 61.7%, respectively. No significant difference was found in the median DFS between patients with Bcl-2 interacting mediator of cell death (BIM) mutant-type and wild-type (NR vs. 41.7 months; p=0.75) and no significant difference was found in the median DFS according to EGFR mutation types (all p>0.05).

Conclusions: The phase II ICAPE study demonstrated that 1.5-year adjuvant therapy with icotinib had a favorable survival benefit in patients with stage IIA-IIIA EGFR-mutant non-small-cell lung adenocarcinoma with a long median DFS and high 5-year OS rates which is consistent with other icotinib’s study. Icotinib is suggested to be used as an adjuvant therapy option in IIA-IIIA EGFR-mutant non-small-cell lung adenocarcinoma.

Citation Format: Kun Qian, Bin Hu, Ming He, Zi-Tong Wang, Yu Liu, Hua-Gang Liang, Zhi-Yong Su, Yu-Shang Cui, Li-Jun Liu, Yi Zhang. Efficacy of icotinib as adjuvant therapy for patients with stage IIA-IIIA EGFR-mutant non-small-cell lung adenocarcinoma: a multicenter, open-label, single-arm, phase II study (ICAPE) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5499.
Abstract 5533: YIV-906 could modulate nuclear factor of activated T-cells (NFAT) activity of T cells for immune checkpoint blockade therapy and CAR T-cell therapy
Authors: Lam Wing , Liu Shwu-Huey , Cheng Peikwen , Cheng Yung-Chi
Published: June 2022

YIV-906 is a standardized botanical drug inspired by a traditional Chinese herbal formulation, historically used to treat gastrointestinal symptoms including diarrhea, nausea, and vomiting. Results from seven Phase I/II to II clinical studies suggest that YIV-906 has potential to prolong survival and improve quality of life for patients who have liver, pancreatic, colorectal, and rectal cancer and received chemotherapy and/or radiation therapy. Currently, a phase II international clinical trial for using YIV-906 plus sorafenib to target HBV positive hepatocellular carcinoma as first line therapy (NCT04000737) had been initialized. Recently, we demonstrated that YIV-906 could enhance anti-tumor activity of anti-PD1 against hepatoma in mice by enhancing both adaptive immunity and innate immunity thought promoting T cell activation by modulating IDO activity and potentiating IFNg action to polarize macrophages into M1-like type. Here, by using Jurkat cells-staphylococcal superantigen E (SEE)-Raji cells cell culture model, we demonstrated that YIV-906 could promote T cell activation with up-regulation of CD69 by modulating nuclear factor of activated T-cells (NFAT) activity. This could be due to that YIV-906 could trigger protein phosphorylation of T cell receptor signaling cascades including, Lck, Fyn, Zap70, LAT and Pyk2. Importantly, YIV-906 could enhance Anti-PD1 action to recuse the depressed NFAT activity of Jurkat cells-PD1 cells when incubated with Raji-PD-L1 cells. In addition, YIV-906 could also enhance NFAT activity triggered by the interaction of chimeric antigen receptor (CAR-CD19-CD3z) on Jurkat cells and CD19 on Raji cells. Component S (Scutellaria baicalensis Georgi) of YIV-906 was found to play key roles of the above activities. Flavonoids of S, such as baicalein, chrysin and oroxylin A, were identified to have modulation effect on NFAT activity. In conclusion, YIV-906 could modulate both adaptive immunity and innate immunity to facilitate immune checkpoint blockade therapy or CAR T-cell therapy for treatment of cancer in patients. This is worthy of further investigation. (Supported by research fund from Yiviva, inc)

Citation Format: Wing Lam, Shwu-Huey Liu, Peikwen Cheng, Yung-Chi Cheng. YIV-906 could modulate nuclear factor of activated T-cells (NFAT) activity of T cells for immune checkpoint blockade therapy and CAR T-cell therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5533.
Abstract 5565: Analysis of immune landscape in hepatocellular carcinoma patients with MDM2/4 mutations
Authors: Wang Xinjun , Zhang Hushan , Yang Yuan , Du Hang , Tang Jingling
Published: June 2022

Background Previous studies indicated that alteration of MDM2/4 was related to poor response even hyper-progressive disease (HPD) to immune checkpoint inhibitors (ICI) therapy. Meanwhile, ICI monotherapy showed low effective rate in hepatocellular carcinoma (HCC), it is still unclear that whether it was associated with HPD-related gene mutation such as MDM2/4. Herein, we analyzed characteristic of MDM2/4 mutation in HCC from tumor immune microenvironment (TIME), to explore the underlying mechanism.

Methods Gene mutation of 2615 patients with HCC was analyzed by next generation sequencing (NGS) in 3D Medicines, a laboratory accredited by CAP and Clinical Laboratory Improvement Amendments (CLIA), from Octomber 2017 to May 2020, 68 tumor tissue samples were collected for analysis of TIME, including CD8+ T cells, CD68+HLA-DR+ M1 macrophages and CD68+HLA-DR- M2 macrophages, CD56bright and CD56dim NK cells infiltrated in the tumor tissue, which were detected by multiple fluorescence immunohistochemistry (mICH).

Results Among these patients with HCC, 19.54% (511/2615) were mutated in gene MDM2/4, 18.9% (493/2165), 0.7% (18/2165) were MDM2 and MDM4, respectively. The 68 samples were divided into two groups, including group with wild type MDM2/4, and group with MDM2/4 alterations. Analysis of immune cell infiltration revealed that almost all of these immune cells we detected were less infiltrated into tumor tissue of patients with MDM2/4 mutation than without MDM2/4 mutation. What’s more, the most significant difference between patients with and without MDM2/4 alteration was infiltration of CD56dim NK cells (p<0.001).

Conclusion The poor response to ICI monotherapy may associated with the high proportion of alteration in gene MDM2/4, which was characterized by low infiltration of immune cells, especially effective NK cells.

Citation Format: Xinjun Wang, Hushan Zhang, Yuan Yang, Hang Du, Jingling Tang. Analysis of immune landscape in hepatocellular carcinoma patients with MDM2/4 mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5565.
Abstract 5596: TNFα production by myeloid DCs in response to rituximab induces monocyte and NK cell proliferation and survival
Authors: Yu Nanmeng , Weiner George J.
Published: June 2022

Background: Rituximab is a central component of chemoimmunotherapy for B cell lymphomas. With over two decades in clinical use, new insights into its mechanisms of action continue to emerge. Rituximab infusion into patients results in elevated levels of TNFα in patient sera. However, our understanding of the mechanism of TNFα production in the context of rituximab and its role in anti-tumor immunity remain limited. In our study, we sought to determine the major producers of TNFα following rituximab treatment and the effect of rituximab-induced TNFα on anti-tumor effector cells.

Methods: Peripheral blood mononuclear cells (PBMCs) from normal donors were cocultured in vitro with CD20-expressing Raji cells for 1 to 7 days. The coculture was treated with rituximab or non-specific antibody trastuzumab. Recombinant TNFα or TNFα blocking antibody infliximab were used to test the effect of TNFα in the rituximab- or trastuzumab-treated coculture system. ELISA was used to evaluate TNFα production in culture supernatant. Multicolor flow cytometry was used to evaluate for phenotypic and functional changes with TNFα treatment or blockade in various immune cell populations.

Results: TNFα was robustly produced by PBMCs when treated with rituximab. This production was mediated by the Fc portion of rituximab antibody, as rituximab Fab elicited very little if any TNFα response from PBMCs. Myeloid dendritic cells (HLA-DR+CD123-CD11c+) were the key producers of TNFα in response to rituximab. In the absence of antibody therapy, recombinant TNFα treatment induced proliferation and survival of two major effector cells in the peripheral blood: monocytes and NK cells as determined by cell count and percent of Ki67+ cells. TNFα blockade using infliximab inhibited monocyte and NK cell proliferation and survival. TNFα blockade also protected Raji cells from rituximab-mediated killing.

Conclusions: Rituximab-induced TNFα production promotes the proliferation and survival of monocytes and NK cells. Myeloid dendritic cells are necessary for TNFα production in this context. These results highlight the complexity of the immune response to rituximab treatment. Additional studies are ongoing exploring the role TNFa plays in the therapeutic response to rituximab.

Citation Format: Nanmeng Yu, George J. Weiner. TNFα production by myeloid DCs in response to rituximab induces monocyte and NK cell proliferation and survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5596.
Abstract 5599: A novel orally available anti-cancer drug candidate, SB17170, represses myeloid-derived suppressor cells by targeting HMGB1
Authors: Choi Young Il , Ahn Sungoh , Kim Hyo Young , Jung Na Jin , Lee Jae Jin , Park Seung Bum
Published: June 2022

Introduction: High Mobility Group Box1 (HMGB1) is a kind of DAMP to modulate immune responses in various conditions, including the tumor microenvironment. In various cancers, it has been reported that cytoplasmic localization of HMGB1 is correlated with poor prognosis. Here, we present a novel small-molecule drug candidate, SB17170, which inhibits immune-suppressive cells in tumor microenvironments by specific binding to HMGB1.

Methods: SB17170 is a pro-drug of active metabolite SB1703 which was identified in cell-based phenotypic screening. SB1703 modulates immune responses by inhibiting the secretion of various cytokines from activated macrophages. HMGB1 was revealed as the target protein of SB1703 using Fluorescence difference In Two-dimensional Gel-Electrophoresis (FITGE). The antitumor activity of SB1703 was analyzed in B16F10 murine syngeneic model.

Results: SB17170 is orally available drug candidate at the clinical development stage for solid tumors. The active metabolite SB1703, bound to HMGB1, was observed in activated MDSC, but not in immature MDSC, and inhibited the activity and cytokine release of MDSC at the submicromolar range. The antitumor activity of SB17170 was observed in B16F10 murine syngeneic model, but not in immunodeficient NOG model, suggesting that SB17170 requires the adaptive immune system for its antitumor activity. The oral treatment of SB17170 in tumor-bearing mice induced intratumor T cell infiltration, but reduced the number of MDSC from day 3. SB17170 also repressed HMGB1 levels as well as MDSC in the blood. In combination with immune checkpoint inhibitors against PD1, PD-L1, and CTLA4, SB17170 enhanced the antitumor responses.

Conclusions: We presented here orally available small-molecule drug candidate, SB17170, which selectively binds to HMGB1 and represses MDSC in tumor microenvironment. SB17170 showed the antitumor activity in B16F10 murine syngeneic models, but not in immunodeficient background, suggesting that its mechanism of action is based on antitumor immune responses.

Citation Format: Young Il Choi, Sungoh Ahn, Hyo Young Kim, Na Jin Jung, Jae Jin Lee, Seung Bum Park. A novel orally available anti-cancer drug candidate, SB17170, represses myeloid-derived suppressor cells by targeting HMGB1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5599.