bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5794: DX2206, a humanized monoclonal antibody that targets IL1RAP, exhibits potent inhibition of IL-1 pathways and activities against tumors in vitro and in vivo
Authors: Liu Qinghao , Ru Yaqi , Jiang Yan , Li Huimin , Li Wenbo , Yang Lan , Shi Qian
Published: March 2024

Background: The Interleukin-1 Receptor Accessory Protein (IL1RAP) is found on cancer cells, stromal cells, and infiltrating immune cells within the tumor microenvironment (TME) of various cancers. It plays an important role in tumor development at various stages by activating IL-1 superfamily pathway, thus become an interesting target in cancer treatment.

Methods: We investigated the correlation between IL1RAP and tumor prognosis through the analysis of the public dataset. An antibody discovery campaign was performed and DX2206 was identified as the top clone against IL1RAP. Epitope of DX2206 was determined by examining the binding of DX2206 with different IL1RAP structural domains and in silico analysis. The activities of DX2206 against IL-1, IL-33, and IL-36 were examined using multiple assays with HEK293-Luc reporter cells, primary HUVEC cells, and A431 human skin squamous carcinoma cells. In vivo efficacy was evaluated in a CDX model.

Results: Based on public data, IL1RAP is overexpressed in various types of cancer patients compared to healthy individuals, and high expression of IL1RAP is associated with poor prognosis in multiple cancer types. Furthermore, high expression of the members of the IL-1 superfamily, such as IL1RAP, IL-1, and IL-36, are negatively correlated with pan-Cancer OS. Our epitope analysis indicated that DX2206 binds to a unique epitope within IL1RAP domain 2. In vitro assays demonstrated that DX2206 inhibited the activities of all three pathways, IL-1, IL-33, and IL-36, with sub-nanomolar IC50s. Simultaneously, it induced a potent ADCC effect in the tumor killing assay. Finally, in a CDX model, DX2206 significantly inhibited tumor growth in vivo.

Conclusions: We discovered a potent antagonist antibody, DX2206, that binds to a unique epitope of IL1RAP, inhibits all three pathways of signaling, and demonstrates in vitro and in vivo activities against tumors. Considering these characteristics, DX2206 emerges as an outstanding preclinical candidate for cancer therapy. IND enabling study was ongoing to expedite the candidate into clinic.

Citation Format: Qinghao Liu, Yaqi Ru, Yan Jiang, Huimin Li, Wenbo Li, Lan Yang, Qian Shi. DX2206, a humanized monoclonal antibody that targets IL1RAP, exhibits potent inhibition of IL-1 pathways and activities against tumors in vitro and in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5794.
Abstract 5817: pH responsive delivery of gemcitabine/pirarubicin co-loaded biodegradable polymeric nanoparticles for synergistic anti-cancer therapy
Authors: Gupta Priya , Kharbanda Surender M. , Singh Harpal
Published: March 2024

Gemcitabine, a nucleoside antimetabolite, is a widely known chemotherapeutic agent being used as a first line treatment alone or in combination with other chemo drugs for different types of cancer. However, due to its extremely short half-life in the body caused by enzymatic degradation and poor pharmacokinetics, the I.V. dosage of administration is quite high i.e., >1000 mg/m2 for metastatic breast cancer treatment. Moreover, gemcitabine in combination with anthracyclines imparts synergy but free anthracyclines are reported to be associated with long term cardiac toxicity. Nanoparticle-based drug delivery systems have provided a befitted solution for improving the poor pharmacokinetic properties and systemic toxicity caused by the chemo drugs because of their ability to improve bioavailability of the drugs at the desired site as well as overcoming multi-drug resistance (MDR).In the present work, PLA-based biodegradable block copolymeric nanoparticles have been employed to co-load Gemcitabine and Pirarubicin for improved anti-cancer activity. Gemcitabine and Pirarubicin have been chemically conjugated to the amphiphilic block copolymer mPEG PLA via a pH responsive Schiff’s Base linkage using a linker molecule Levulinic acid. The prepared PIRA/GEM co-loaded nanoparticles exhibited an optimum size, zeta potential and polydispersity index i.e., 187 ± 3.5 nm, -10 ± 2.0 and < 0.1 PDI respectively. Further, in the drug release experiments, these Nps displayed sustained and higher drug release in lysosomal pH (pH 5.0) than in the physiological buffer environment (pH 7.4) attributed to the pH sensitive bonding. The co-loaded Nps were prepared in multiple ratios (Pira: Gem - 1:1, 1:3, and 3:1) and investigated for in-vitro cellular inhibition studies in comparison to singly loaded drug Nps and corresponding free drug formulations in various breast cancer cell lines. Additionally, apoptotic studies revealed significant enhancement in synergistic activity in the case of PIRA/GEM co-loaded Nps in comparison to conventional free drug formulations. In conclusion, this nano-formulation demonstrated excellent anti-cancer activity against breast cancer cells therefore it may be used as a potential candidate for therapeutic use.

Citation Format: Priya Gupta, Surender M. Kharbanda, Harpal Singh. pH responsive delivery of gemcitabine/pirarubicin co-loaded biodegradable polymeric nanoparticles for synergistic anti-cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5817.
Abstract 583: Spatiotemporal analyses of longitudinal specimens reveal mechanisms of response and resistance to immune checkpoint blockade in metastatic melanoma
Authors: Zhang Gao , Coussens Lisa , Herlyn Meenhard , Flaherty Keith T. , Boland Genevieve , Mills Gordon
Published: March 2024

Although durable responses to immune checkpoint blockade (ICB) therapies exhibit by a subgroup of patients with metastatic melanoma, most of patients have no response or develop to acquired resistance to ICB therapies within few years. Molecular mechanisms of primary and acquired resistance to ICB therapies are still elusive, which warrants further elucidation. Here, we used a holistic approach to profile 35 longitudinal tumor specimens at pre-, on-, and post-treatment time points which were derived from 7 patients (3 responders and 4 non-responders) with metastatic melanoma who progressed on sequential ICB therapies, including anti-PD-1 and anti-CTLA-4 therapies. We integrated analyses of RNA sequencing, Whole-exome Sequencing (WES), NanoString nCounter vantage 3D, Cyclic Immunofluorescence (Cyc-IF), NanoString Digital Spatial Profiling (DSP) and Multiplex Immunohistochemistry (mIHC) data of these longitudinal tumor specimens to elucidate evolutionary trajectories that occurred in both the tumor and the tumor immune microenvironment (TiME) that may have orchestrated response and resistance to ICB therapies. Simultaneous analyses of genomic, transcriptomic and proteomic data identified the re-activation of MAPK-RAS as well as PI3K pathway upon or after ICB therapies, which may elucidate the mechanism of resistance to ICB therapies. Spatially-resolved, image-based immune monitoring analysis at single cell resolution revealed that the activation status of T cell markers and T-cell checkpoint is conversely associated with potential mechanism of resistance to ICB therapies. In summary, integrated analyses of muti-oics and spatially image-based data from longitudinal tumor specimens allow us not only to reveal the dynamic co-revolution of both tumor and immune cells in TiME following sequential ICB therapies but also to provide a comprehensive perspective to molecular mechanisms of response and resistance to ICB therapies in patients with metastatic melanoma.

Citation Format: Gao Zhang, Lisa Coussens, Meenhard Herlyn, Keith T. Flaherty, Genevieve Boland, Gordon Mills. Spatiotemporal analyses of longitudinal specimens reveal mechanisms of response and resistance to immune checkpoint blockade in metastatic melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 583.
Abstract 5830: A first-of-its-kind model that reconstitutes targeted drug-induced cellular transdifferentiation
Authors: Gopal Priyanka , Abazeed Mohamed
Published: March 2024

Introduction: Lung tumors treated with targeted therapies ultimately relapse due to intra-genic resistance mutations, bypass pathway activation, or cellular lineage changes. Newer precision therapies have higher selectivity and potency against both resistant and activating gene mutations, resulting in a significant increase in incidence of cellular transdifferentiation. The most common form of transdifferentiation is the change from lung adenocarcinomas (LUADs) to small cell lung cancer (t-SCLC) upon drug treatment which remains very poorly understood.

Methods: We have combined patient derived xenografts (PDX) and ex vivo lines with multi-omic characterization, high-content image-based morphometry and fluorescence tracking, and single-cell barcode tracing to better understand the process of lung tumor transdifferentiation.

Results: We have developed a first-of-its-kind t-SCLC model that reconstitutes ex vivo LUAD to SCLC transdifferentiation. Genomic and transcriptomic analyses of our NSCLC PDX collection identified tumors with mutation in TP53 and RB1, two genes that are altered in virtually all de novo SCLCs. PDX sample CBX336 was identified as having mutations in both TP53 and RB1, in addition to expressing the KRASG12C oncogene. Upon treatment with Sotorasib, CBX336 tumors initially demonstrated slow tumor growth, followed by a dramatic increase in the growth after prolonged drug exposure. Our experimental and computational data suggest a highly coordinated procession toward transdifferentiation with the parallel upregulation of the neuroendocrine transcription factor NEUROD1 across numerous epithelial cellular clones.

Conclusions: Our new experimental system allows characterization at the single-cell level. Ongoing work includes the integration of new resources to study lineage reprogramming, and advancing new therapeutic strategies.

Citation Format: Priyanka Gopal, Mohamed Abazeed. A first-of-its-kind model that reconstitutes targeted drug-induced cellular transdifferentiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5830.
Abstract 5851: Dysregulated RNA splicing promotes AML quiescence and chemoresistance
Authors: Wang Eric , Han Cuijuan , Calderon Alexander , Lawal Abimbo , Hariramani Nidhi , Crosse Edie , Bradley Robert
Published: March 2024

Chemotherapy is the first-line treatment for patients with acute myeloid leukemia (AML). Although most achieve initial remission, an estimated 50% of patients will relapse with poor clinical outcome. The paucity of genetic lesions in AML patients that relapse from chemotherapy implicate non-genetic alterations that mediate chemoresistance. In this study, we conducted a longitudinal analysis of alternative splicing changes in a cohort of 19 AML patients at diagnosis and relapse post-chemotherapy treatment. We found that the long isoform of the transcription factor-encoding gene RUNX1 (also known as RUNX1C) is upregulated in AML relapse cohorts and conferred chemotherapy resistance. Mechanistically, we show that B cell translocation gene 2 (BTG2) is an RUNX1C isoform-specific transcriptional target that promote transition into a quiescent and treatment-resistant state. Direct targeting of RUNX1C mRNA augments chemotherapy response in AML patient-derived xenograft (PDX) models in vivo. These findings uncover an isoform-specific functionality that influences chemotherapy responsiveness and offers a therapeutic strategy to sensitize leukemic cells to conventional chemotherapy treatments.

Citation Format: Eric Wang, Cuijuan Han, Alexander Calderon, Abimbo Lawal, Nidhi Hariramani, Edie Crosse, Robert Bradley. Dysregulated RNA splicing promotes AML quiescence and chemoresistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5851.
Abstract 586: Tumor cell-intrinsic PD-1 activation drives therapeutic resistance in colorectal cancer cells
Authors: Mok Ho Kit , Yapp Donald , Tai Isabella
Published: March 2024

Background/Aim: Despite advancements in diagnosis and treatment, advanced CRC remains a formidable treatment challenge with limited therapeutic options because these tumors are resistant to chemo-, radio- and targeted-therapies. Emerging research shows that the presence of tumor cell-intrinsic PD-1 (ciPD-1) in various tumor types is involved in tumorigenicity and therapy-refractory disease. For example, ciPD-1 promotes tumor growth in melanoma and liver cancer, but in lung cancer, ciPD-1 exhibits tumor-suppressive behavior. These findings highlight the intriguing possibility that ciPD-1 may exert context specific functions within the tumor, beyond its well-known role in immune response suppression. Consequently, the present study addressed the pressing need to explore the effects of immune checkpoint inhibitors within broader tumor context and tumor microenvironment. We have established drug-resistant CRC cells and found that ciPD-1 was upregulated in these cells. This, together with an observation that ciPD-1-mediated survival signaling pathways was activated in CRC patient populations, prompted us to investigate the role of ciPD-1 in regulation of therapeutic resistance in CRC in the absence of immune cells.

Methods: We evaluated the clinicopathological relevance of ciPD-1 and its correlation with disease progression in CRC samples from clinical cohorts. Monoclonal antibody inhibition and siRNA interference methods were used to characterize the functional roles of ciPD-1 in regulating therapeutic resistance in CRC. The gene expression profiles of PD-1-High and PD-1-Low patient groups retrieved from clinical cohorts were compared to identify ciPD-1-medatied survival pathways in CRC patients.

Results: We found that ciPD-1 had a critical role in regulating CRC tumorigenicity and survival outcomes. Tumors with high expression levels of ciPD-1 also showed higher mutation rate and levels of microsatellite instability. Exposing CRC cells to chemotherapy, radiation, and nutrient deprivation increased ciPD-1 levels. In line with these observations, drug-resistant CRC cells also expressed higher levels of ciPD-1. The inhibition of ciPD-1 in CRC cells by monoclonal antibody or siRNA interference decreased cell proliferation and self-renewal rates, while enhancing treatment efficacy.

Conclusion: Our studies reveal that CRC cells increase ciPD-1 expressions in response to drug treatment and targeting ciPD-1-mediated survival pathways can delay the onset of drug resistance and promote therapeutic sensitiveness in CRC cells.

Citation Format: Ho Kit Mok, Donald Yapp, Isabella Tai. Tumor cell-intrinsic PD-1 activation drives therapeutic resistance in colorectal cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 586.
Abstract 5869: Investigation of molecular alterations associated with double resistance to BRAF and MEK inhibition in melanoma
Authors: Isaak Armond J. , Clements GeGe R. , Huang Lei , Qin Yifei , Zho Qiang , Merlino Glenn , Yu Yanlin
Published: March 2024

More than 50% of melanomas harbor activating BRAF kinase mutations, with BRAFV600E representing more than 90% of BRAF mutations. Inhibition of mutant BRAF by BRAF inhibitors (BRAFi) in patients with advanced melanoma yields a remarkable initial clinical response. Limited duration response and disease recurrence of inhibitors occurs due to acquired drug resistance. Recently identified mechanisms of MAPK hyperactivation in acquired resistance to BRAFi have encouraged clinicians to employ a combination of BRAF and MAPK inhibitors to block the MAPK signaling pathway more effectively. However, most patients treated with this combination therapy still relapse due to de novo drug resistance. Therefore, innovative strategies are still necessary to improve the precision and durability of anti-melanoma therapies. To investigate the mechanism of both BRAFi and MEKi resistance (double resistance, DR) in mutant BRAF melanomas, we have developed models from four human melanoma cell lines to explore the hypothesis that molecular alterations are related to double resistance to BRAFi and MEKi in melanoma. We have found that BRAFi-MEKi double-resistant models exhibit distinct differences in morphology and growth kinetics. Specifically, BRAFi-MEKi double-resistant human melanomas express a higher level of FGFb and PAI-1 expression. We confirmed that overexpression of FGFb and PAI-1 in parental cells could increase the ability to resist BRAF and MEK inhibition. Additionally, we discovered that decreased expression of FGFb and PAI-1, via knock-down, inhibition, or CRISPR in double resistant cells, can restore cell sensitivity to treatments of BRAFi and MEKi. To further elucidate the role of FGFb and PAI-1 on resistant melanoma, we have extended our scope to in vivo mouse xenograft models. Our findings uncovered the mechanism of how melanoma cells can escape BRAFi and MEKi attacks and offer a rational strategy to guide future clinical treatments.

Citation Format: Armond J. Isaak, GeGe R. Clements, Lei Huang, Yifei Qin, Qiang Zho, Glenn Merlino, Yanlin Yu. Investigation of molecular alterations associated with double resistance to BRAF and MEK inhibition in melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5869.
Abstract 5876: ALDH3A1 as a predictive marker for gemcitabine treatment in pancreatic cancer
Authors: Kim Jin Su , Keum Ji Young , Park Chan Hee , Bang Seungmin
Published: March 2024

Background: Pancreatic cancer is one of the incurable cancer. The currently preferred chemotherapy regimens, including gemcitabine, do not extend patient survival by more than a year, and studies on drug resistance mechanisms or biomarkers for the drug sensitivity are very limited. Aldehyde dehydrogenase (ALDH) is a family of enzymes that play an essential role in cell survival and protection. In cancer cells, it is thought that overexpression of the ALDHs confers a survival advantage to the cells, which is associated with a poor prognosis. In this study, we analyzed the drug sensitivity between ALDH3A1 expression and gemcitabine in PDAC cells.

Method: In this study, we investigated the relationship between ALDH3A1 expression and gemcitabine sensitivity using 8 pancreatic cancer cell line. We observed changes in the pattern of ALDH3A1 expression in established gemcitabine resistance pancreatic cancer cell line. Following this, we functionally inhibited ALDH3A1 to determine its impact on gemcitabine sensitivity using shRNA method. To elucidate the molecular mechanisms related with ALDH3A1, we performed multi-omics analysis such as transcriptomics and proteomics.

Results: As a results, there was a negative correlation between ALDH3A1 expression (Protein & mRNA) and gemcitabine resistance 8 pancreatic cancer cell lines. However, in established gemcitabine resistance BxPC3 cells compared to control cells, gemcitabine resistance increased more than 1000 fold while the protein expression was decreased. In these results correlated with inhibition of ALDH3A1 expression using shALDH3A1 experiments both change ALDH3A1 expression and gemcitabine resistance. In biological phenotype experiments, cell proliferation and migration increased in the ALDH3A1 inhibition groups. When using combination treatment of gemcitabine and CB29, a known ALDH3A1 inhibitor, drug resistance increased by more than 2,000 fold in the combination treatment groups. In RNAseq analysis, Adherens junction, Ras signaling, Axon guidance, and JAK-STAT signaling pathway related genes were up regulated in shALDH3A1 treatment group compared control.

Conclusion: In this study, we demonstrated the negative correlation between ALDH3A1 and gemcitabine resistant in pancreatic cancer cell lines and suggesting that it may serves as a predictive marker for gemcitabine treatment in pancreatic cancer patients.

Keywords: Pancreatic ductal adenocarcinoma (PDAC), Aldehyde dehydrogenase 3 family member A1 (ALDH3A1), Gemcitabine sensitivity.

Citation Format: Jin Su Kim, Ji Young Keum, Chan Hee Park, Seungmin Bang. ALDH3A1 as a predictive marker for gemcitabine treatment in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5876.
Abstract 5881: Upregulation of TET2 expression by DNA methyltransferase (DNMT) inhibitors is associated with resistance in DNMT1 knockout colorectal cancer cells
Authors: Laranjeira Angelo B. , Nguyen Dat , Pelosof Lorraine C. , Doroshow James H. , Yang Sherry X.
Published: March 2024

Ten-eleven-translocation 2 (TET2) is a member of the TET family proteins (TET1-3) that convert 5-methylcytosine to 5-hydroxymethylcytosine (5-hmC) in DNA and causes site-specific DNA demethylation. The effects of DNMT1 on TET2 phenotype following DNMT inhibitor treatment is unclear in human cancer. In colorectal cancer HCT116 cells with DNMT1 gene intact (DNMT1+/+) and deletion (DNMT1−/−) status, we found that TET2 expression was robustly increased in DNMT1−/− cells after treatment with 0.5 µM and 5 µM decitabine for 72 h, 96 h, and 120 h. The augmentation in TET2 expression was accompanied by a dose-dependent re-expression of p16ink4A in DNMT1−/− cells. Particularly, TET2 upregulation was associated with resistance to DNMT inhibitors, showing a lack of induction of DNA damage, cell-cycle arrest and apoptosis after drug exposure in DNMT1−/− compared to DNMT1+/+ cells. The treatment with 4’-thio-5-aza-2’-deoxycytidine (aza-T-dCyd) only up-regulated TET2 and re-expressed p16ink4A at the lower dose of 0.5 µM, which was consistent with our previous findings that high dose of aza-T-dCyd at 5 µM predominantly eliminates the cancer cells with severe DNA damage by undergoing apoptosis and cell death (Scientific Reports, 13:5964, 2023). Moreover, both decitabine and aza-T-dCyd had minimal effects on TET2 upregulation and p16ink4A re-expression in cells with intact DNMT1 gene. The data suggest that the absence of DNMT1 gene made the cells prone to TET2 upregulation upon DNMT inhibitor challenges. Future study is needed to investigate the interactive relationship between DNMT1 and TET2 as well as demethylation, and its impact on cancer treatment with DNMT inhibitors.

Citation Format: Angelo B. Laranjeira, Dat Nguyen, Lorraine C. Pelosof, James H. Doroshow, Sherry X. Yang. Upregulation of TET2 expression by DNA methyltransferase (DNMT) inhibitors is associated with resistance in DNMT1 knockout colorectal cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5881.
Abstract 5902: Targeting MAPK-driven tumors via inhibition of MAP2K4
Authors: Wade Mark , Tamanini Emiliano , Unbekandt Mathieu , Wallis Nicola , Lyons John , Munck Joanne , Woodhead Andrew , Schopf Patrick , Stow Jessie , East Charlotte , Clark Mellissa , Denis Jeffrey St. , Pathuri Puja
Published: March 2024

MAPK pathway activation is a feature of multiple tumor types. Drugging KRAS and BRAF, the two main oncogenic drivers in the MAPK pathway, has proven successful in the clinic. Inhibition of the downstream effectors, MEK and ERK, can also induce tumor regression. Despite this, many tumors are intrinsically resistant to MAPK pathway inhibitors, or acquire resistance under selective pressure to drug treatment. This creates a need for combination treatments to improve clinical responses. A synthetic lethal (SL) interaction between inhibition of the MAPK pathway and blockade of JNK-JUN signaling has recently been described1. Specifically, data from yeast genetics and CRISPR knockout experiments in human cells have identified MAP2K4 as a potential therapeutic target that could be combined with MAPK inhibitors. To date, however, no potent MAP2K4 inhibitors with in vitro and cellular selectivity against key anti-targets have been reported. Here, we describe the development of potent covalent inhibitors of MAP2K4 kinase activity. Biochemical and cell-based assays show that the compound(s) are selective for MAP2K4 versus anti-targets including MAP2K7 and ERK kinases. The combination of MAP2K4 and MEK/ERK inhibitors was effective in cell lines driven by MAPK signaling. These data provide the rationale for further development of MAP2K4 inhibitors to advance our understanding of this novel drug combination.

References: 1. Xue Z, Vis DJ, Bruna A, Sustic T, van Wageningen S, Batra AS, et al. MAP3K1 and MAP2K4 mutations are associated with sensitivity to MEK inhibitors in multiple cancer models. Cell Res. 2018; 28:719-29.

Citation Format: Mark Wade, Emiliano Tamanini, Mathieu Unbekandt, Nicola Wallis, John Lyons, Joanne Munck, Andrew Woodhead, Patrick Schopf, Jessie Stow, Charlotte East, Mellissa Clark, Jeffrey St. Denis, Puja Pathuri. Targeting MAPK-driven tumors via inhibition of MAP2K4 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5902.
Abstract 5905: Propentofylline enhances GBM sensitivity to temozolomide via targeting TROY signaling
Authors: Eghlimi Ryan , Nascari David , Beniwal Angad , Alton Drake , Grief Dustin , Loftus Joseph , Haluska Melanie , Coleman David , Tran Nhan
Published: March 2024

Glioblastoma (GBM) is a high grade glioma that accounts for the majority of primary malignant brain tumors. The standard of care for GBM consists of maximal surgical resection, concurrent radiation and temozolomide (TMZ), and adjuvant TMZ. However, this has only led to a modest increase in median patient survival. TROY (TNFRSF19) is an orphan member of the TNF receptor superfamily that is differentially upregulated in GBM with low expression in normal brain tissue. Previously, we have reported that TROY is overexpressed in GBM and signals to mediate cell invasion and therapeutic resistance. Propentofylline (PPF) is a well-studied synthetic methylxanthine derivative that has strong BBB penetrance. We have shown that PPF decreases TROY expression in gliomas, inhibits invasion, and sensitizes GBM to TMZ in vitro. Here we examined the efficacy of PPF in combination with TMZ using in vivo studies of intracranial models of GBM patient-derived xenograft (PDX) models in murine. We tested 3 models of GBM PDX cells with various TROY expression levels (GBM8-high TROY; GBM43-moderate TROY; GBM22-low/no TROY). Our intracranial PDX experiments showed that PPF treatment alone did not increase survival in all PDX cells. The combination of PPF and TMZ treatment did provide a survival benefit (p < 0.039) relative to TMZ alone (only in GBM8-high TROY and GBM43-moderate TROY) that was partially lost when treatment was discontinued. However, continuous PPF administration following a concomitant PPF and TMZ treatment course led to extended survival (p < 0.0015) compared to TMZ alone resulting in increased DNA damage (γH2AX) and apoptotic markers (Cleaved Caspase-3). Immunohistochemical analyses showed that TROY expression was decreased in tumors treated with PPF. In addition, PPF-treated tumors showed a differential myeloid population with well circumscribed tumors as compared to control-treated or TMZ-treated tumors. Thus, our data demonstrates that PPF may provide a pharmacological approach to targeting TROY concomitant with standard-of-care to increase patient survival.

Citation Format: Ryan Eghlimi, David Nascari, Angad Beniwal, Drake Alton, Dustin Grief, Joseph Loftus, Melanie Haluska, David Coleman, Nhan Tran. Propentofylline enhances GBM sensitivity to temozolomide via targeting TROY signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5905.
Abstract 5931: Investigating the therapeutic potential of STK17A inhibition in GBM
Authors: Castro Jesus R.
Published: March 2024

For decades, the survival rate for glioblastoma (GBM) has remained nearly stagnant, and currently the 5-year survival rate is only 5%. There is an unmet medical need for therapeutic development, as GBM is the most common primary brain tumor, yet only four FDA approved drugs have been developed for GBM over the last century. GBM is notoriously heterogeneous, and this has posed a challenge for researchers seeking to find therapeutic targets. However, by taking advantage of RNA sequencing, a potential biomarker and target for GBM has been identified: the kinase STK17A (Serine/Threonine Kinase 17A), also known as DRAK1. We confirmed that STK17A is overexpressed in brain cancers by analyzing public databases and single-cell RNA sequencing data from GBM patients, and further associated it with poor patient outcome. Little is known about STK17A, but it has been found to be involved with cell proliferation, tumorigenesis, and tumor metastasis. The role of STK17A in GBM pathophysiology and its therapeutic potential as a drug target remains a critical knowledge gap.In order to better understand STK17A’s role in GBM pathophysiology, we first knocked down STK17A in GBM cell lines and determined that STK17A had functional roles in proliferation and morphology. Similar conclusions were drawn after knocking down STK17A in vivo in GBM xenograft mouse models. These findings supported STK17A as a viable therapeutic target. We then designed and optimized novel brain-penetrant STK17A inhibitors with IC50 values of <20nM in enzyme assays and <1μM in cell-based targeting engagement and proliferative assays. The designed and prepared novel STK17A inhibitors were further evaluated through kinase enzymatic assays and biological assays as well as in vitro proliferation and toxicity assays. We further characterized the inhibitors by showing Drug Metabolism and Pharmacokinetics (DMPK) properties in vivo in mouse models at 10 mg/kg via oral administration. We then used these potent, selective, and highly brain penetrant STK17A inhibitors to investigate the anti-tumor effects of STK17A inhibition in GBM in vivo and demonstrate the efficacy of our novel STK17A inhibitors.In conclusion, this work seeks to contribute to the field of targeted therapies for GBM by optimizing and examining the first iterations of novel brain penetrant STK17A inhibitors, initiating studies for the treatment of GBM in vitro and in vivo, and providing proof of efficacy for further studies in GBM patients. Ultimately, the results from our findings will lead to novel strategies for targeted drug development and more robust therapeutic options for GBM patients.

Citation Format: Jesus R. Castro. Investigating the therapeutic potential of STK17A inhibition in GBM [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5931.
Abstract 5991: Improved venetoclax therapy by a novel conjugate with artemisinin by NOXA-mediated reduction of Mcl-1 and cyclin D1 protein in myeloid leukemia cells
Authors: Zhang Jingyi , Zhang Zhenwei , Waxman Samuel , Zhao Linxiang , Jing Yongkui
Published: March 2024

Evasion of apoptosis is crucial for the growth, survival and chemoresistance of myeloid leukemia. The Bcl-2 selective inhibitor venetoclax is the only apoptosis inducer approved for clinical use. Venetoclax in combination with hypomethylating agents or low-dose cytarabine has now become the standard care for elderly AML patients. However, a sizeable fraction of patients are either refractory to venetoclax combination therapy or ultimately relapse. High or induced expression of Mcl-1 and Bcl-xL mediates venetoclax resistance. Previously we reported that artemisinin enhances venetoclax apoptosis induction by degrading Mcl-1 through NOXA induction. We designed a novel conjugate A1 of venetoclax with dihydroartemisinin. A1 shows dual functions of inhibiting Bcl-2 and inducing NOXA. A1 treatment releases Bim from both Bcl-2 and Mcl-1, further degrades Mcl-1 protein, and presents ten-fold stronger apoptotic induction ability in venetoclax insensitive cells. Acquired increase of Mcl-1 protein was observed in venetoclax resistant MOLM-13/VEN cells, which are sensitive to A1-induced apoptosis. In Bcl-xL expressing venetoclax refractory leukemia cells A1 obtains a new mechanism of inhibiting cell cycling by downregulating cyclin D1 through a new NOXA/cyclin D1 cascade, mediated through the endoperoxide moiety of artemisinin and intracellular iron, independent of Bcl-2 inhibition. We reveal a new compound A1 overcoming venetoclax resistance by NOXA-mediated degradation of Mcl-1 and cyclin D1 protein.

Citation Format: Jingyi Zhang, Zhenwei Zhang, Samuel Waxman, Linxiang Zhao, Yongkui Jing. Improved venetoclax therapy by a novel conjugate with artemisinin by NOXA-mediated reduction of Mcl-1 and cyclin D1 protein in myeloid leukemia cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5991.
Abstract 60: Functional mapping of glioblastoma recurrence reveals targetable dependencies in an axonal guidance pathway in highly invasive brain cancers
Authors: Singh Sheila Kumari , Chokshi Chirayu , Shaikh Vaseem , Brakel Benjamin , Anand Alisha , Venugopal Chitra , Kislinger Thomas , Henry Kevin , Rossotti Martin , Brown Kevin , Lazo John , Moffat Jason
Published: March 2024

Resistance to genotoxic therapies and tumor recurrence are hallmarks of glioblastoma (GBM), an aggressive brain tumor. Here, we explore the functional drivers of post-treatment recurrent GBM. By conducting genome-wide CRISPR-Cas9 screens in patient-derived GBM models, we uncover distinct genetic dependencies in recurrent tumor cells that were absent in their patient-matched primary predecessors, accompanied by increased mutational burden and differential transcript and protein expression. These analyses map a multilayered genetic response to drive tumor recurrence, identifying protein tyrosine phosphatase 4A2 (PTP4A2) as a novel modulator of self-renewal, proliferation and tumorigenicity at GBM recurrence. Genetic perturbation or small molecule inhibition of PTP4A2 represses axon guidance activity through a dephosphorylation axis with roundabout guidance receptor 1 (ROBO1), exploiting a functional dependency on ROBO signaling. Importantly, engineered anti-ROBO1 single-domain antibodies also mimic effects of PTP4A2 inhibition. Since a pan-PTP4A inhibitor was limited by poor penetrance across the blood brain barrier (BBB) in vivo, a second-generation chimeric antigen receptor (CAR)-T cell therapy was engineered against ROBO1 that elicits specific and potent anti-tumor responses in vivo. A single dose of anti-ROBO1 CAR-T cells doubles median survival in patient-derived xenograft (PDX) models of recurrent glioblastoma, and also eradicates tumors in around 50% of mice engrafted with PDX models of lung-to-brain metastases and pediatric relapsed medulloblastoma. We conclude that functional reprogramming drives tumorigenicity and dependence on a multi-targetable PTP4A-ROBO1 signaling axis at GBM recurrence, with potential in other malignant brain tumors.

Citation Format: Sheila Kumari Singh, Chirayu Chokshi, Vaseem Shaikh, Benjamin Brakel, Alisha Anand, Chitra Venugopal, Thomas Kislinger, Kevin Henry, Martin Rossotti, Kevin Brown, John Lazo, Jason Moffat. Functional mapping of glioblastoma recurrence reveals targetable dependencies in an axonal guidance pathway in highly invasive brain cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 60.
Abstract 6027: 89Zr-matuzumab and 225Ac-matuzumab as a theranostic for epidermal growth factor receptor-positive KRAS wild-type colorectal and breast cancer xenografts
Authors: Tikum Florence Anjong , Fonge Humphrey , Njotu Fabrice , Babeker Hanan , Pougoue Jessica K. , Henning Nikita , Doroudi Alireza
Published: March 2024

Background: About 80% of colorectal cancer (CRC) and 50 % of Triple-Negative breast cancer (TNBC) patients overexpress epidermal growth factor receptor (EGFR). Mutations in the KRAS oncogene (present in 40% of mCRC) lead to constitutive over-activation of EGFR and drive de novo resistance to anti-EGFR drugs. Here, we propose to target KRAS-mutant/BRAF mutant EGFR positive mCRC and TNBC using 225Ac-labeled matuzumab, a humanized anti-EGFR monoclonal antibody.

Methods: p- -SCN-macropa was used to conjugate matuzumab for radiolabeling with 225Ac and SCN-deferoxamine was used to conjugate matuzumab for labelling with 89Zr. The radioimmunoconjugates were characterized by flow cytometry, HPLC and iTLC. in vitro cytotoxicity was evaluated in EGFR-positive mCRC, TNBC cell lines and 3D spheroids with different levels of EGFR density. Tumor growth was monitored using digital caliper. Mice were treated with either 10 MBq of 89Zr-matuzumab for imaging or three doses of 13 KBq/dose administered of 225Ac-matuzumab 10 days apart. In vivo study endpoint was tumor volume greater than or equal to 1500 mm3.

Results: Flow cytometry showed about 95% binding to the cells in all EGFR-positive colorectal cell lines (DLD-1, SW620, SNU-C2B, HT-29) and breast cancer cell lines (MDA-MB-468, MDA-MB-231). in vitro studies showed enhanced cytotoxicity of 225Ac-matuzumab compared with matuzumab. IC50 in the MDA-MB-468 cell line for 225Ac-matuzumab (1.86 ± nM) was 35 times more effective than matuzumab (65.25± 7 nM). Similar trends were observed in the other KRAS-mutant mCRC cell lines and breast cancer cell lines. In 3D spheroid models, the IC50 of 225Ac-matuzumab (3.0 ± 2 nM) in MDA-MB-468, was 20.79 times more effective than matuzumab (62.3 ± 1.38 nM). Similar trends were observed for all the other spheroid models as well. High uptake of 89Zr-matuzumab was observed in both mCRC and TNBC xenografts. 225Ac-matuzumab slowed tumor growth rate in MDA-MB-468 and MDA-MB-231 tumors models compared with control antibody or non-treated controls for 30 days. This study is still ongoing and will last for 2 more months.

Conclusion: 225Ac-matuzumab shows very promising outcomes in KRAS-mutant mCRC models and breast cancer models and warrants further investigation.

Citation Format: Florence Anjong Tikum, Humphrey Fonge, Fabrice Njotu, Hanan Babeker, Jessica K. Pougoue, Nikita Henning, Alireza Doroudi. 89Zr-matuzumab and 225Ac-matuzumab as a theranostic for epidermal growth factor receptor-positive KRAS wild-type colorectal and breast cancer xenografts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6027.
Abstract 6042: CBP-8008: A first-in-class targeted pan-Bet protein degradation therapy using bi-specific XDC (Bi-XDC) technology for TNBC and mCRPC
Authors: Wang Tao , Zhang Zhiguang , Wang Guitao , Pan Fan , Huang Robert
Published: March 2024

Bi-XDC is a breakthrough cellular targeting technology using multi-targeting ligands to effectively deliver the payload to and into specific cells. Several anticancer Bi-ligand drug conjugates including CBP-1008, CBP-1018, and CBP-1019 have been brought into various clinical stages in China and US. Targeted protein degradation molecules can degrade previously “undruggable” target proteins through their catalytic mechanism of action. The field target protein degradation has evolved since 2001, and more than 20 PROTACs are under clinical trials at different stages.

To increase the efficacy vs. tolerability window, we combine Bi-XDC technology and the catalytic approach of targeted protein degradation, to form C-PROTAC, by taking advantage of our privileged Bi-XDC technology and PROTAC’s degradation property. Further medicinal chemistry optimization, spacer optimization, and evaluation of many linker payloads led to the identification of our preclinical candidate CBP-8008, a highly potent pan-Bet protein degrader conjugated to bi-ligand via a cleavable linker.

A small panel of cell lines was screened to identify which tumors were sensitive to the pan-Bet protein degradation. All the tested breast cancer and prostate cell lines were the most sensitive to the payload. CBP-8008 had a high affinity to the Prostate Specific Membrane Antigen (PSMA) and the folate receptor alpha (FRα). Much more CBP-8008 were binding the 293T-FP which overexpress both FR-α and PSMA than the cell lines which only express one target (293T-F or 293T-P) or negative cell line (293T). CBP-8008 can quickly enter cells through endocytosis after treatment for 15 min, and degradation of BRD2, BRD3, and BRD4 was observed in MDA-MB-231 after 6 h, which was similar to its payload. The compound was very stable in mouse and human plasma in vitro, and limited free payload was detected which potentially avoids hematotoxicity in clinical. In the tumor-beaning mice DMPK study, fewer free payload was detected in 6 hours while much more free payload was detected in the tumor than in the blood and the time was extended to 72 hours after a single dose treatment. We evaluated CBP-8008 in TNBC and mCRPC xenograft model and robust efficacy was observed as lower as 3 MPK, significantly better than BMS-986158, a potent Bet inhibitor in clinical.

In conclusion: CBP-8008 is currently in preclinical development as a potential first-in-class pan-Bet protein degradation therapy using Bi-XDC technology for TNBC and mCRPC

Citation Format: Tao Wang, Zhiguang Zhang, Guitao Wang, Fan Pan, Robert Huang. CBP-8008: A first-in-class targeted pan-Bet protein degradation therapy using bi-specific XDC (Bi-XDC) technology for TNBC and mCRPC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6042.
Abstract 6045: Development and characterization of ATC-324: An AUTOTAC-based androgen receptor degrader for prostate cancer treatment
Authors: Pham Tri , Bae Tae Hyun , Sung Ki Woon , Najy Abdo , Zamiri Alaleh , Jang Hyejeong , Mun Su Ran , Kim Seongho , Shi Dongping , Kregel Steven , Heath Elizabeth , Cher Michael , Kwon Yong Tae , Kim Hyeong-Reh
Published: March 2024

Prostate cancer (PCa) progression is largely driven by the androgen receptor (AR), making it a prime target for therapy. However, therapy resistance often arises due to AR mutations and splice variants, such as AR-v7. AUTOTAC (AUTOphagy-TArgeting Chimera) is a novel protein degradation platform that utilizes the autophagy-lysosomal pathway to selectively degrade disease-causing proteins. In this study, we characterize ATC-324, an AUTOTAC-based AR degrader designed for the treatment of PCa. ATC-324 comprises enzalutamide linked to YT 6-2, a small molecule activator of the autophagy receptor p62/SQSTM1. ATC-324 induces the formation of the AR/p62 complex while activating autophagic flux, leading to the autophagy-lysosomal degradation of AR. To characterize ATC-324, we employed various AR-dependent, AR-null, and enzalutamide-resistant PCa cell lines. Given that bone metastasis is a major clinical complication of castrate-resistant PCa associated with greater morbidity and mortality, we utilized the bone-in-culture array (BICA) assay, an ex vivo bones culture model, to investigate the impact of ATC-324 on PCa cell survival and growth in the bone microenvironment. We demonstrated that ATC-324 effectively degrades wild-type, mutant, and splice variants of AR. In addition, ATC-324 induces AR-dependent apoptosis and cytotoxicity. Importantly, ATC-324 maintains its potency in enzalutamide-resistant PCa cells. Utilizing the BICA assay, we showed that ATC-324 exhibits cytotoxicity against 22Rv1 bone micrometastases at even lower concentrations than in 2D cell culture. In conclusion, our study demonstrates the successful development and characterization of ATC-324 as a potent and selective degrader of various forms of AR. Furthermore, its effectiveness against enzalutamide-resistant cells indicates its capability to overcome therapy resistance. The observed cytotoxicity against bone micrometastases suggests a therapeutic potential for combating bone metastasis, a major complication of castration-resistant PCa. Our study underscores the potential of the AUTOTAC platform to selectively degrade disease-causing proteins

Citation Format: Tri Pham, Tae Hyun Bae, Ki Woon Sung, Abdo Najy, Alaleh Zamiri, Hyejeong Jang, Su Ran Mun, Seongho Kim, Dongping Shi, Steven Kregel, Elizabeth Heath, Michael Cher, Yong Tae Kwon, Hyeong-Reh Kim. Development and characterization of ATC-324: An AUTOTAC-based androgen receptor degrader for prostate cancer treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6045.