bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract LB160: The mouse mammary tumor virus mediates the antineoplastic action of decitabine
Authors: Light Sarah , Montazer Maziar , Wycoff Cade , Tuttle Richard , Brola Andrew , Wycoff William , Johnson Ryan , Liu Yingguang 
Published: April 2024

Abstract
The purpose of this study is to clarify the role of the mouse mammary tumor virus (MMTV) in cancer growth and in mediating the antineoplastic effect of decitabine, a DNA demethylating agent. In vitro studies have shown that decitabine inhibits cancer cell proliferation by stimulating endogenous retroviruses which in turn activates the production of cytostatic interferon beta (IFN-β). We investigated the potential involvement of endogenous MMTV and the mouse IFN-β in the pharmacodynamics of decitabine using stable knockdown cell lines and MMTV hyper-infection. For the first time, we show that knockdown of MMTV or IFN-β in a mouse mammary cancer cell line (4T1) both rendered the cancer cells more resistant to decitabine in mice bearing 4T1-derived mammary cancer. Mechanistically, decitabine enhanced MMTV expression on the RNA level in both control tumors and tumors with MMTV knockdown, although the degree of enhancement was limited in knockdown tumors. Conversely, infection of a mouse colon cancer cell line (MC38) with MMTV released from 4T1 cells rendered the colon cancer cells more sensitive to decitabine. These data confirm the viral mimicry hypothesis as the mechanism of DNA demethylating agents. Practically, our research suggests the possibility of combining the use of an exogenous virus and a DNA demethylating agent as a new approach to cancer treatment.
Citation Format: Sarah Light, Maziar Montazer, Cade Wycoff, Richard Tuttle, Andrew Brola, William Wycoff, Ryan Johnson, Yingguang Liu. The mouse mammary tumor virus mediates the antineoplastic action of decitabine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB160.
Abstract LB164: Inducing immunogenic cell death in difficult-to-treat cancers with an orally-bioavailable GPX4 inhibitor
Authors: Read Timothy J. , Steel Richard , Golialei Ardeshir , Rimel Jenna , Damon Leah , Azofeifa Joey 
Published: April 2024

Abstract
Recent advancements in immunotherapy have transformed cancer treatment, resulting in extended survival times for some patients. However, despite these advancements, many patients do not benefit from immunotherapy because of an immunosuppressive tumor microenvironment. Consequently, there is a need for new strategies to improve the effectiveness of immunotherapy by stimulating inflammatory immunogenic cell death in tumors. Ferroptosis is a recently-described form of non-apoptotic cell death that induces a uniquely inflammatory immunogenic cell death. Glutathione Peroxidase 4 (GPX4) is the cell’s major defense system against ferroptosis as it is the only known enzyme capable of reducing toxic lipid hydroperoxides to inert lipid alcohols. Here we describe the discovery of a series of potent and selective small molecule GPX4 inhibitors that result in significant tumor growth inhibition in several aggressive tumor CDX models. We verified induction of ferroptosis in tumors using known biomarkers of ferroptosis such as HMOX1 mRNA induction as well as with 4-HNE staining. GPX4 target engagement and degradation was confirmed by mass spectrometry and western blot in tumors. GPX4 inhibition, when combined with PDL-1 blockade in a syngeneic sarcoma model, resulted in sustained significant tumor growth inhibition throughout the course of a 28-day study at well-tolerated doses when compared to either monotherapy alone. Current studies are underway to more carefully define the unique immunogenic cell death imparted by GPX4 inhibition and resulting ferroptosis.
Citation Format: Timothy J. Read, Richard Steel, Ardeshir Golialei, Jenna Rimel, Leah Damon, Joey Azofeifa. Inducing immunogenic cell death in difficult-to-treat cancers with an orally-bioavailable GPX4 inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB164.
Abstract LB178: HP518, an oral AR-targeting PROTAC for the treatment of AR positive triple negative breast cancer with a novel mechanism of action
Authors: Li Jing , Yuan Hongwei , Chen Kefan , Huo Yongxu , Liu Guoqing , Du Wu , Li Xinghai 
Published: April 2024

Abstract
Triple negative breast cancer (TNBC) accounts for 15-20% of all breast carcinomas and has poor prognosis. Chemotherapy is the mainstay treatment for TNBC patients, yet with limited clinical benefit. Androgen receptor (AR) is expressed in approximately 50% of TNBC tumors and thus the anti-androgen therapy could be a promising solution for the treatment of AR+ TNBC. Nevertheless, AR inhibitors including enzalutamide and bicalutamide or the androgen biosynthesis inhibitor abiraterone have failed to demonstrate satisfying anti-tumor activity in clinical trials. We have discovered HP518, an AR-targeting PROTAC (proteolysis targeting chimera) that induces potent degradation of both the wild-type AR and AR mutants. HP518 is currently under the clinical development for the treatment of mCRPC. Here we report the preclinical data on HP518 for the treatment of AR+ TNBC. HP518 robustly degrades AR in multiple TNBC cell lines with a half-maximal degradation concentration (DC50) &lt; 1 nM. HP518 strongly inhibits AR+ TNBC cell growth, whereas the AR inhibitor enzalutamide does not show significant anti-proliferative effect on these cells in the presence or absence of androgen. Consistent with the in vitro results, HP518 significantly and dose-dependently inhibits tumor growth in MDA-MB-453 cell line derived tumor xenograft (CDX) and patient-derived xenograft (PDX) mouse models. PI3KCA activating mutations are frequently expressed in AR+ TNBC. HP518 in combination with alpelisib, a PI3Kα inhibitor shows a synergistic anti-tumor activity. Mechanistically, HP518, but not AR inhibitor enzalutamide downregulates the mRNA expression levels of a set of DNA replication-related genes in AR+ TNBC cells, indicating a novel and ligand-independent role for AR in regulating growth of AR+ TNBC cells. Therefore, HP518, an AR-targeting PROTAC degrader holds great potential to fulfill the unmet clinical needs for the AR+ TNBC therapy. Selected pre-clinical data will be presented. HP518 structure will not be disclosed.
Citation Format: Jing Li, Hongwei Yuan, Kefan Chen, Yongxu Huo, Guoqing Liu, Wu Du, Xinghai Li. HP518, an oral AR-targeting PROTAC for the treatment of AR positive triple negative breast cancer with a novel mechanism of action [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB178.
Abstract LB189: Elucidating a mechanistic link between progranulin and lysosomal function in SW13 cells: Implications for inflammation and lipid metabolism
Authors: Leyva Kathryn J. , Yang Andrew Z. , Biparva Pegah , Okonya Chika , Uppalapati Chandana K. , Harrison Alisha M. , Pascual Agnes S. , Hull Elizabeth E. 
Published: April 2024

Abstract
The SW13 human adrenocortical carcinoma line is a uniquely powerful model in which to probe the relationship between progranulin processing and cellular activity as it exists in two epigenetically distinct subtypes. The SW13- subtype has an epithelial morphology and is highly proliferative, while the SW13+ subtype has a mesenchymal-like phenotype and a higher metastatic potential. These two subtypes both express progranulin and interconvert by epigenetic mechanisms, as treatment of SW13- cells with histone deacetylase inhibitors (HDACi) adopt a SW13+ phenotype. Progranulin is composed of 7½ highly conserved granulin repeats which are subject to proteolytic processing and may serve as a prognostic biomarker in cancer as progranulin units regulate varied cellular activities including proliferation, migration, inflammation, and lysosomal function. Thus, biological activity of progranulin is dependent on the cellular proteases expressed. Indicative of differential processing, treatment of SW13- cells with exogenous progranulin results in an increase in growth rate, while no effect on SW13+ cell growth was observed. As the SW13+ subtype expresses a higher amount of progranulin than the SW13- subtype, these data are consistent with an inability of SW13+ to process endogenous progranulin to mitogenic granulin unit(s). Immunoblotting with granulin-specific antibodies indicates that progranulin may be processed differently in each subtype. In this work, we focused on lysosomes as a potential site for differential processing of progranulin for two reasons. First, lysosomal proteases have been shown to process progranulin and progranulin itself plays a role in lysosome maturation. Second, differences in lysosomal pH between the two subtypes have been detected using two pH-sensitive dyes which localize to the lysosome. Interestingly, proteomic analysis of lysosomes isolated from each subtype confirms lysosomal dysfunction and suggests upregulation of inflammatory proteins in SW13+ cells. Both proteomics and lipidomics suggest alterations in lipid metabolism. Ongoing experiments will address whether restoration of lysosomal function impacts progranulin production and/or processing in SW13 subtypes.
Citation Format: Kathryn J. Leyva, Andrew Z. Yang, Pegah Biparva, Chika Okonya, Chandana K. Uppalapati, Alisha M. Harrison, Agnes S. Pascual, Elizabeth E. Hull. Elucidating a mechanistic link between progranulin and lysosomal function in SW13 cells: Implications for inflammation and lipid metabolism [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB189.
Abstract LB190: Cancer-stromal cells interaction dominates the expression of pro-tumor decreted protein chitinase-3-like-1 in pancreatic cancer
Authors: Su Pei-Chia (Peggy) , Wang Yi-Ching 
Published: April 2024

Abstract
In the context of the tumor microenvironment (TME), a substantial increased secreted protein, chitinase-3 like-protein-1 (CHI3L1) has been observed, emanating from various cell types such as cancer cells, macrophages, and T cells. The development of an immunosuppressive and fibrotic TME has been implicated in CHI3L1-mediated cancer progression. Despite recognizing the potential for CHI3L1 blockade to facilitate cancer regression, there remains a limited understanding of the regulatory mechanisms governing the expression of this tumor-promoting protein within cancer cells. Our investigations, along with others, have identified low levels of CHI3L1 protein in normal epithelial cells, in stark contrast to its abundant presence in pancreatic cancer tumor specimens. We propose that the interaction between cancer and stromal cells in the TME induces CHI3L1 expression within cancer cells. To test this hypothesis, we established a co-culture system involving cancer and stromal cells including pancreatic stellate cells, macrophages and T cells to emulate the TME of pancreatic cancer. Subsequently, we observed a ten-fold increase in CHI3L1 expression in cancer cells upon exposure to co-culture media. Through secretomic analysis, C-X-C motif chemokine ligand 10 (CXCL10) emerged as a potential inducer of CHI3L1 expression in response to co-culture media. CXCL10/CXCR3 signaling has been reported to correlate with poor prognosis in pancreatic cancer, while their role in disease development is still unclear. Concurrently, Gene Set Enrichment Analysis (GSEA) identified the activation of TNFα signaling via NF-κB and TGF-β pathways in pancreatic cancer patients with high CHI3L1 expression. Notably, chromatin-immunoprecipitation and promoter activity assays validated the direct binding and transcriptional regulatory role of NF-κB, a downstream transcription factor of CXCL10, on CHI3L1 gene in cancer cells. In addition, epigenetic reprogramming occurred during co-culture media education. Our observations indicated demethylation of the CHI3L1 promoter during co-culture media exposure, a phenomenon confirmed to be mediated by STAT3 activation. In summary, this study elucidates, for the first time, the intricate crosstalk between cancer and stromal cells within the TME of pancreatic cancer as a pivotal factor for the transcriptional and epigenetic dysregulation of CHI3L1, which then contributes to TME remodeling and malignant pancreatic cancer progression.
Citation Format: Pei-Chia (Peggy) Su, Yi-Ching Wang. Cancer-stromal cells interaction dominates the expression of pro-tumor decreted protein chitinase-3-like-1 in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB190.
Abstract LB192: AGR2 knockdown reduces cell proliferation and increases endoplasmic reticulum proteotoxic stress in pancreatic cancer
Authors: Salu Philip , Reindl Katie 
Published: April 2024

Abstract
Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal solid malignancy with low survival rates due to a dense stroma, abnormal gene expression patterns, and limited treatment options. Anterior gradient 2 (AGR2) is often overexpressed in many cancers, including PDAC. AGR2 belongs to the protein disulfide isomerase family of proteins and is located in the endoplasmic reticulum, where it helps with protein-disulfide isomerase reactions to ensure proper protein folding. However, the molecular mechanisms underpinning AGR2 overexpression in PDAC pathophysiology are not well understood. Gene expression data obtained from the pancreatic adenocarcinoma (PAAD) dataset shows that AGR2 is overexpressed in PDAC tumors compared to normal tissues. We confirmed this gene over-expression in PDAC tumors and multiple pancreatic cancer cell lines using fluorescent microscopy, RT-qPCR, and western blotting. Using stable inducible short hairpin (shRNA) technology, we showed that AGR2 knockdown significantly decreases the viability and colony-forming ability of HPAF-II and PANC-1 cells. Gene Ontology (GO) enrichment analysis revealed that AGR2 knockdown suppresses a host of protein biosynthesis pathways, including protein targeting and localization to the endoplasmic reticulum (ER). Significantly, ER stress was induced in knockdown cells, shown by the activation of unfolded protein response, suggesting an accumulation of unfolded proteins. To determine the effects of unfolded protein accumulation on the ER, we performed transmission electron microscopy. Here, the results show an increase in the ER lumen size of knockdown cells compared to controls. Interestingly, we observed a decrease in mitochondria size and confirmed the increased expression of mitochondria fission proteins DRP1 and MFF. Finally, flow cytometry analysis revealed increased apoptosis in AGR2 knockdown cells compared to controls. Overall, our data provide insights into the role of AGR2 in PDAC tumorigenesis. However, more research is warranted to determine if AGR2 could be a potential therapeutic target.
Citation Format: Philip Salu, Katie Reindl. AGR2 knockdown reduces cell proliferation and increases endoplasmic reticulum proteotoxic stress in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB192.
Abstract LB207: C5ar1 is a novel biomarker and potential therapeutic target in advanced cutaneous squamous cell carcinoma
Authors: Heiskanen Lauri , Nissinen Liisa , Siljamäki Elina , Knuutila Jaakko , Pellinen Teijo , Kallajoki Markku , Heino Jyrki , Riihilä Pilvi , Kähäri Veli-Matti 
Published: April 2024

Abstract
Cutaneous squamous cell carcinoma (cSCC) is the most common metastatic skin cancer and the metastatic disease is associated with poor prognosis. At present, there are no established molecular markers to predict the metastasis risk and prognosis of patients with primary cSCC. Recently, the role of specific complement components in the progression of cSCC has been shown. Here, we have examined the role of complement C5a receptor C5aR1 in the progression and metastasis of cSCC. The results show that the expression of C5aR1 is increased in cSCC cells in 3D spheroid coculture model in the presence of fibroblasts and that treatment with recombinant C5a increases invasion of cSCC cells in this model. Staining for C5aR1 was detected on the surface of tumor cells in the invasive edge of human cSCC xenograft tumors in vivo. Staining of metastatic and non-metastatic primary human cSCCs, premalignant epidermal lesions and normal skin for C5aR1 with multiplexed fluorescence and chromogenic immunohistochemistry revealed stronger expression of C5aR1 on surface of cSCC tumor cells compared to epidermal cells in cSCC in situ, actinic keratosis and normal skin. Increased expression of C5aR1 on tumor cell surface was associated with the metastasis risk of primary cSCCs and independently predicted poor disease-specific survival of patients with primary cSCC. These results reveal the role of C5aR1 in cSCC progression and identify C5aR1 as a novel biomarker for metastasis risk and poor prognosis of patients with cSCC. The results also suggest C5aR1 as a novel therapeutic target for treatment of locally advanced and metastatic cSCC.
Citation Format: Lauri Heiskanen, Liisa Nissinen, Elina Siljamäki, Jaakko Knuutila, Teijo Pellinen, Markku Kallajoki, Jyrki Heino, Pilvi Riihilä, Veli-Matti Kähäri. C5ar1 is a novel biomarker and potential therapeutic target in advanced cutaneous squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB207.
Abstract LB208: An intricate connection between canonical Wnt and MAPK/ERK signaling drives the partial hybrid EMT state involving FOXC2/p63 activation leading to cancer stemness and metastasis
Authors: Liang Huizhi , Benard Outhiriaradjou , Ren Zuen , Suyama Kimita , Wang Jingli , Griffen Anthony , Wang Hao , LeFave Lindsay , Norton Larry , Hazan Rachel B. 
Published: April 2024

Abstract
The epithelial to mesenchymal transition (EMT) is a dynamic process underlying metastasis. Here we show that TCF1, a TCF7 gene product, promotes a hybrid epithelial/mesenchymal (E/M) phenotype in basal breast cancer cells that was enriched in stemness and metastasis as compared to cells residing in the M-like state. E/M cells (CD104highCD44high) were enriched in canonical Wnt signaling, thereby upregulating FOXC2 which was turn able of converting M into E/M cells. Consistent with the E/M state, FOXC2 upregulated TA and ΔNp63 isoforms which control epithelial differentiation and Wnt signaling via β4 integrin/CD104 and Frizzled 7 upregulation respectively. Importantly, Wnt3a was able of stimulating ERK phosphorylation in E/M cells leading to FOXC2 and p63 upregulation thereby preventing E/M to M differentiation. These findings were further corroborated by ATAC-sequencing pointing predominantly to FOXC2 as a master regulator of the E/M state that was suppressed by ERK inhibition. Together, these results demonstrate that TCF7 stimulates Wnt3a/ERK activation which in turn activates the FOXC2/p63 axis, thereby promoting the hybrid EMT state underlying stemness and metastasis.
Citation Format: Huizhi Liang, Outhiriaradjou Benard, Zuen Ren, Kimita Suyama, Jingli Wang, Anthony Griffen, Hao Wang, Lindsay LeFave, Larry Norton, Rachel B. Hazan. An intricate connection between canonical Wnt and MAPK/ERK signaling drives the partial hybrid EMT state involving FOXC2/p63 activation leading to cancer stemness and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB208.
Abstract LB215: Polymerase θ (POLθ) inhibitors (novobiocin, ART-558, RP6685) were tested with 22 approved and investigational agents in multi-cell type spheroids of genetically selected patient-derived human tumor cell lines
Authors: Teicher Beverly A. , Dexheimer Thomas S. , Silvers Thomas , Coussens Nathan P. , Eder J Paul , Doroshow James H. 
Published: April 2024

Abstract
The potential of novobiocin to augment cancer chemotherapy was explored in the late 1980s and early 1990s in tumor cells and tumor-bearing mice and in Phase 1 clinical trials with cyclophosphamide or cisplatin. The molecular target of novobiocin was identified to be DNA POLθ which has a role in repair of DNA double strand breaks (DSB) during mitosis. Genetic alterations which may increase or decrease POLθ inhibitor effects have been elucidated. Thirty patient-derived tumor cell lines with known BRCA, ATM, ATR, POLQ, XRCC1, PALB2, PARP1, and LIG3 alterations were screened in a complex spheroid assay (tumor cells, endothelial cells, mesenchymal stem cells) with a POLθ inhibitor (novobiocin, ART-558, or RP6685), alone or in simultaneous combination with a FDA approved or investigational anticancer small molecule, using a 7-day exposure and a CellTiter-Glo 3D luminescence endpoint. As single agents, the POLθ inhibitors had little or no cytotoxicity. Potentiation of the topoisomerase II inhibitors doxorubicin (DOX) and etoposide by the POLθ inhibitors ART-558 or RP6685 was observed in spheroids grown from the serous endometrial adenocarcinoma 922993-354-T-J3, which has ATM and BRCA2 variants. The 379773-124-R-J2 endometrioid endometrial adenocarcinoma which harbors mutant POLθ demonstrated antagonism with ART-558 in combination with PARP inhibitors and less than additive to additive cytotoxicity in combination with DOX. Activity of the Chk1/2 inhibitor prexasertib was potentiated by either ART-558 or RP6685 in the 922993-354-T-J3 complex spheroids. The combination of POLθ inhibitor ART-558 and the Chk1/2 inhibitor prexasertib produced up to 1 log increase in cytotoxicity in the 922993-354-T-J3 complex spheroids. KRAS G12D inhibitor MRTX-133 cytotoxicity against 186277-243-T-J2 colon adenocarcinoma with the KRAS G12D variant was potentiated by either ART-558 or RP6685. Potential combinations to advance into in vivo studies will be presented. This project was funded in part with federal funds from the NCI, NIH, under contract no. HHSN261201500003I.
Citation Format: Beverly A. Teicher, Thomas S. Dexheimer, Thomas Silvers, Nathan P. Coussens, J Paul Eder, James H. Doroshow. Polymerase θ (POLθ) inhibitors (novobiocin, ART-558, RP6685) were tested with 22 approved and investigational agents in multi-cell type spheroids of genetically selected patient-derived human tumor cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB215.