bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3715: Pharmacological targeting of circadian clock genes reveals regulatory mechanisms of E-box regulated genes in cancer
Authors: Pan Yuanzhong , Lenz Heinz-Josef , Torres Evanthia Roussos , Kay Steve A.
Published: April 2023

Transcription factors (TFs) are key regulators of homeostasis and cancer. Recent advances in pharmacological targeting of TFs makes them valuable targets in various diseases, but systems-level understanding of the function and regulation of TFs from different families in cancers remains lacking. Our lab and collaborators have been developing new small molecules to modulate the functions of key regulators of the circadian clock BMAL1 and CLOCK, which are bHLH family TFs that activate gene expression by binding to a DNA motif called E-box, with a consensus sequence of CANNTG. E-boxes are ubiquitous in the genome and broadly regulate essential physiological processes of the cell, but their molecular biology in cancer is largely unknown. In the current work we tested the ability of small molecules to regulate the expression of BMAL1 and CLOCK target genes. Across different cell lines of various cancer types, we found that stabilization of one of the negative regulators of CLOCK, CRY2, by our novel compound called SHP1705, is the most consistent to suppress canonical BMAL1 target genes. GO and GSEA analysis of RNA-seq data shows that SHP1705 also significantly changed most core regulators of circadian rhythms as well as other E-box-binding proteins. However, SHP1705 has IC50 values above 10µM in most tested cells, creating a challenge for efficacy in a clinical setting. Because BMAL1 requires the proteasome to sustain the turnover of a transcription burst, we hypothesized proteasome inhibitors (PI) MG132 and carfilzomib may synergize with SHP1705. Consequently, we found strong synergy with both PIs. Analysis of TF-target genes in combination-treated cells reveals significant changes in expression profiles, suggesting that these genes are regulated by E-box, and other related/alternative promoter elements: CCAAT-box, CG-rich motifs, and ATGGC. Co-enrichment of these elements revealed the components of E-box containing promoters and showed potential properties of E-box-regulated gene expression. Co-existence of these motifs in the same proximal promoter also potentially allows RNAPII multiple choices of alternative promoters and could promote expression of variants in cancer cells. Our results support the necessity of inhibiting the whole promoter and provide an example of how to approach designer pharmacological strategies to achieve this purpose.

Citation Format: Yuanzhong Pan, Heinz-Josef Lenz, Evanthia Roussos Torres, Steve A. Kay. Pharmacological targeting of circadian clock genes reveals regulatory mechanisms of E-box regulated genes in cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3715.
Abstract 3719: Targeting the eIF6 and 60S ribosomal subunit interaction interface in cancers
Authors: Harish Kavya Meena , Biswas Aparna , Roshan Poonam , Origanti Sofia
Published: April 2023

Translational control is integral to cancer initiation and progression. A subset of translation initiation factors are deregulated in cancers to facilitate their rampant growth and proliferation. Eukaryotic translation initiation factor 6 (eIF6) is one such factor that is over expressed in many cancers including lung, colon, ovarian and breast cancers, and deregulation of eIF6 is correlated with a poor cancer prognosis. Association of eIF6 with 60S is critical for 60S assembly. However, eIF6 must be released from 60S prior to translation to permit inter subunit interactions between 60S and 40S and to facilitate the formation of translationally proficient 80S complex. Release of eIF6 is deregulated in the ribosomopathy- Shwachman Diamond Syndrome that is predisposed to leukemias. Also, loss of eIF6 markedly delays tumorigenesis without affecting normal growth, which presents eIF6 as a viable therapeutic target. A potential therapeutic strategy is to target the eIF6 and 60S ribosomal interaction interface. Through extensive biophysical analyses, we had identified residues that are critical for the interaction between eIF6 and 60S ribosomal subunit. We show that targeting these key residues in the eIF6-60S interaction interface markedly delays colonic cancer growth and inhibits protein synthesis. Interestingly, targeting eIF6 leads to an upregulation of p53 independent of the DNA damage response, suggesting that ribosomal stress contributes to the stabilization of p53. Future studies will determine the mRNA targets that are translationally deregulated by inactivation of eIF6. We will also determine the effect of targeting eIF6 function in inhibiting tumor growth and progression in vivo.

Citation Format: Kavya Meena Harish, Aparna Biswas, Poonam Roshan, Sofia Origanti. Targeting the eIF6 and 60S ribosomal subunit interaction interface in cancers. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3719.
Abstract 3720: Cysteine palmitoylation of astrocyte elevated gene-1/Metadherin (AEG-1/MTDH) regulates its biological and immunological activity
Authors: Del Carmen Camarena Maria , Komaniecki Garrison , Manna Debashri , Mendoza Rachel , Subler Mark A. , Windle Jolene J. , Dozmorov Mikhail G. , Lin Hening , Sarkar Devanand
Published: April 2023

Non-alcoholic steatohepatitis (NASH) is a major risk factor for hepatocellular carcinoma (HCC). Astrocyte elevated gene-1/Metadherin (AEG-1/MTDH) augments steatosis, inflammation, and tumorigenesis, thereby promoting the whole spectrum of this disease process. Targeting AEG-1 is a potential interventional strategy for NASH and HCC. Thus, proper understanding of the regulation of this molecule is essential. We found that AEG-1 is palmitoylated at residue Cysteine75 (Cys75). Mutation of Cys75 to Serine (Ser) completely abolished AEG-1 palmitoylation.Systematic knockdown studies identified zinc finger DHHC-type palmitoyltransferase 6 (ZDHHC6) as the palmitoyltransferase catalyzing the process. To obtain insight into how palmitoylation regulates AEG-1 function, we generated a knock-in mouse by CRISPR/Cas9 in which Cys75 of AEG-1 was mutated to Ser (AEG-1-C75S). No developmental or anatomical abnormality was observed between AEG-1-wild type (AEG-1-WT) and AEG-1-C75S littermates. However, global gene expression analysis by RNA-sequencing unraveled that signaling pathways and upstream regulators, which contribute to cell proliferation, motility, inflammation,angiogenesis, and lipid accumulation, are activated in AEG-1-C75S hepatocytes compared toAEG-1-WT. Feeding these mice with high fat/high sugar diet for 20 weeks showed accumulation of T-regulatory cells and exhausted CD8 T-cells in the livers of AEG-1-C75S mice vs AEG-1-WT, and only in females, suggesting that inhibition of AEG-1 palmitoylation creates an immunosuppressive milieu favoring tumorigenesis. Collectively, these findings suggest that AEG-1-C75S functions as dominant positive, and palmitoylation restricts oncogenic and NASH-promoting functions of AEG-1. Studies are ongoing to unravel the mechanism by which palmitoylation restricts AEG-1 function, and to understand the sex-specific immune-modulatory role of AEG-1 palmitoylation in hepatocarcinogenesis.

Citation Format: Maria Del Carmen Camarena, Garrison Komaniecki, Debashri Manna, Rachel Mendoza, Mark A. Subler, Jolene J. Windle, Mikhail G. Dozmorov, Hening Lin, Devanand Sarkar. Cysteine palmitoylation of astrocyte elevated gene-1/Metadherin (AEG-1/MTDH) regulates its biological and immunological activity. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3720.
Abstract 3727: Development of a new All-In-One inducible lentiviral shRNA/gRNA Vector
Authors: Wu Lipeng , Su Hua , Fellows Justin , Fu Mao , Heller Julian , Park Brian , Yin Dezhong
Published: April 2023

Tet-On is a powerful inducible system and a classical tool to regulate gene expression in mammalian cells. It has also been applied to regulate Pol III-driven transcription, such as shRNA or gRNA driven by a U6 or H1 promoter. However, all of the current versions of Tet-On shRNA vectors are based on H1-2O2 or U6-2O2 promoters, which are only compatible with first-generation tetracycline repressor TetR. In addition, these promoters have the problem of driving downstream transcription without the binding of the Tet regulatory protein. Here, we developed a new system that is built upon tetracycline activator protein, Tet-On 3G, combined with a new structure of Tet responsive promoter H1-4O4, which tightly regulates the downstream transcription of gRNA or shRNA. The responsiveness of our system to Doxycycline regulation is dramatically improved compared with the current versions. The new Tet-On system is further optimized into a compact structure to be compatible with the lentivirus package (All-In-One Lenti-Tet-On system), which still keeps the leaky expression at an undetectable level. Combined with all these features, the new generation of the Tet-On system offers broad applications in gene knocking down and genomic editing.

Citation Format: Lipeng Wu, Hua Su, Justin Fellows, Mao Fu, Julian Heller, Brian Park, Dezhong Yin. Development of a new All-In-One inducible lentiviral shRNA/gRNA Vector. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3727.
Abstract 3733: Disconnect between APOBEC3 expressions and mutations across cancers
Authors: Khosh Azad , Hamidi Hamid , Rahimi Hamzeh , Ebrahimi Diako
Published: April 2023

DNA of many tumors is barraged by C-to-T/G mutations within TCW (W:T,A). These mutations are attributed to the aberrant expression and activity of APOBEC3 enzymes. They have been shown to account for many driver mutations in genes such as PIK3CA, ERBB2, and PPP2R1A, however their precise source and also their roles in tumor development, evolution, and patient survival are debated. Currently, quantification of APOBEC3 expression changes in tumor cells is confounded by the ubiquitous expression of these enzymes in infiltrating immune cells. In this study, we used quantitative biology approaches to separate the expression profiles of APOBEC3 enzymes in tumor and tumor microenvironment cells and determine their associations with tumor mutational signatures. For this purpose, we analyzed diverse datasets including TCGA tumor/matched normal RNAseqs, tumor somatic mutations, cell line RNAseqs and mutations, estimates of tumor purities and immune cell compositions, and expression of purified cell populations to precisely determine how APOBEC3 enzymes are dysregulated across tumors and whether their dysregulations are proportional to tumor mutational signatures. Unexpectedly, we found that dysregulation of APOBEC3 enzymes is independent of tumor C-to-T/G mutational burden. Importantly, our data suggest that this disconnect is likely not due to the episodic bursts of APOBEC3-induced mutations in cancer.

Citation Format: Azad Khosh, Hamid Hamidi, Hamzeh Rahimi, Diako Ebrahimi. Disconnect between APOBEC3 expressions and mutations across cancers. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3733.
Abstract 3734: Neuroendocrine differentiation (ND) in sensitivity of neuroendocrine tumor (NET) cells to ONC201/TIC10 cancer therapeutic
Authors: Ding Elizabeth C. , El-Deiry Wafik S.
Published: April 2023

Neuroendocrine tumors (NETs) harbor neuroendocrine differentiation (ND) with specific markers including protein gene product 9.5 (PGP9.5) and Chromogranin A (CgA). In prostate cancers (PC), ND is induced by BRN2/SOX2 transcription factors. NET-like cells with low or absent androgen receptor (AR) signaling cause hormone therapy resistance and poor prognosis in PC. Small cell lung carcinoma (SCLC), a high-grade NET, presents with metastasis early and has poor survival. ONC201/TIC10 is a small molecule inducer of TRAIL signaling in clinical trials. ONC201 antagonizes dopamine D2 or D3 receptors (DRD2/DRD3) and is an agonist of mitochondrial caseinolytic protease P (ClpP) resulting in activation of DR5/TRAIL-dependent apoptosis involving the integrated stress response (ISR). ONC201 is active in various malignancies including H3K27M-mutated glioma and NETs expressing high levels of DRD2. We hypothesized that altered BRN2/SOX2 may impact NET apoptosis by ONC201 through the ISR and TRAIL/DR5. We analyzed the expression of neuroendocrine markers PGP9.5, CgA, SOX2, and BRN2, as well as markers of TRAIL signaling pathway markers ATF4, DR5, ClpP, ClpX, and DRD2/DRD3 in PC and SCLC cell lines (N=6) ± treatment with ONC201. Specifically, we compared pre-treatment protein expression levels with the IC50. Our results reveal that DU145 (IC50=3.11μM), PC3 (IC50=3.02μM), and LNCaP (IC50=1.33μM) are ONC201 sensitive. H1417 SCLC expresses CgA, unlike PC3 and DU145. PGP9.5 is expressed in these lines. PGP9.5 is expressed in PC3, DU145, H1417, and H1048 but not in LNCaP and 22RV1. BRN2 is expressed in PC3, H1417, and H1048 but not DU145, LNCaP, or 22RV1. ClpX is expressed in all 6 lines but at lower levels in SCLC. ClpP is expressed in the 6 lines. DR5 is expressed at higher levels in PC3, DU145, LNCaP, and 22RV1 PC versus H1417 and H1048 SCLC. SOX2 is expressed at high levels in H1417 cells. These results are establishing the landscape of ND in PC and SCLC lines for further experimentation and testing of our hypothesis. To characterize the association of BRN2 dysregulation with ONC201 sensitivity, we are performing BRN2/SOX2 knockdown experiments using siRNA and evaluating effects towards ONC201 sensitivity. Our results provide insights into molecular mechanisms of ND in PC and SCLC sensitivity to ONC201. We are also currently working to overexpress BRN2 and SOX2 in cell lines to analyze the impact on neuroendocrine differentiation and ONC201 sensitivity.

Citation Format: Elizabeth C. Ding, Wafik S. El-Deiry. Neuroendocrine differentiation (ND) in sensitivity of neuroendocrine tumor (NET) cells to ONC201/TIC10 cancer therapeutic. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3734.
Abstract 3747: Transcribed ultra-conserved regions (TUCRs): A first computational and molecular characterization of an understudied class of molecules in gliomas
Authors: Gibert Myron K. , Chagari Bilhan , Roig-Laboy Christian , Sarkar Aditya , Abounader Roger
Published: April 2023

Gliomas are the most common malignant primary brain tumors. Particularly, glioblastoma (GBM) is the most common and deadliest malignant brain tumor. Most glioma research has focused on protein-coding genes and much less on the non-coding transcripts that make up 98% of cellular RNA. Transcribed Ultra-Conserved Regions (TUCRs) represent an understudied class of molecules that are found highly conserved across multiple species, including 100% conservation in mouse and rat genomes. These 481 transcripts are highly resistant to variation and are commonly deregulated in cancer, which suggests regulatory and functional importance when considered along with their high degree of conservation. We performed the first-ever characterization of TUCRs in gliomas in silico. Using an elaborate workflow, we annotated and identified TUCRs that are deregulated in GBM and low-grade glioma (LGG), associated with patient outcomes, and predicted their function in glioma initiation and progression. Most TUCRs were long non-coding RNAs. Of these, we investigated the most highly upregulated intergenic TUCR, uc.110, in vitro and in vivo in glioma cell lines. Knockdown of uc.110 expression via siRNA resulted in reduced glioma cell accumulation, viability, and invasion in vitro while reducing tumor volume and increasing overall survival in vivo. Concurrent lentiviral overexpression of uc.110 partially rescued wild-type expression, accumulation, viability, and invasion in vitro. Therefore, it is likely that this TUCR is functioning as an oncogene within the context of GBM. Our study represents the first comprehensive characterization of TUCRs in gliomas and can serve as a foundation and framework for similar studies in gliomas and other cancers.

Citation Format: Myron K. Gibert, Bilhan Chagari, Christian Roig-Laboy, Aditya Sarkar, Roger Abounader. Transcribed ultra-conserved regions (TUCRs): A first computational and molecular characterization of an understudied class of molecules in gliomas. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3747.
Abstract 3749: Oncogenic role of Epstein-Barr virus lnc-BARTs in EBV associated tumors
Authors: JIAYAN LIU , Mok Bobo Wing-Yee , He Songtao , Chen Honglin
Published: April 2023

While majority of humans infected with Epstein-Barr virus (EBV) is asymptomatic for whole life, EBV is found to associate with several human cancers, including Burkitt’s lymphoma, Hodgkin’s diseases, post-transplant lymphoproliferative disorder (PTLD), nasopharyngeal carcinoma (NPC) and gastric carcinoma. Among these EBV associated tumors, EBV genome is found in 100% of NPC tumor cells. EBV establishes a latent infection in NPC cells, expressing few viral proteins, but elevated levels of non-coding RNAs transcribed from the BamHI-A region of the EBV genome, designated BamHI-A rightward transcripts (BARTs). The family of EBV BART RNAs comprises BART-microRNAs (miRNAs) and long non-coding RNAs (lnc-BARTs). While versatile functions of BART miRNAs have been revealed, little is known about the role of EBV lnc-BARTs. Here, we provided evidence to show that BARTs mRNA which derived from multiple exons of BART function as regulatory long non-coding RNA, namely lnc-BARTs, in modulating the core network for maintaining EBV latency and promoting NPC oncogenesis through epigenetic mechanisms. Our results showed that the apoptosis rate of NPC cell lines with knockdown of EBV lnc-BARTs was significantly increased, suggesting that lnc-BARTs have an anti-apoptotic effect in EBV associated tumors. MS analysis was performed to identify host factors which interact with EBV lnc-BARTs in NPC cells. Lnc-BARTs were shown to directly interact with several transcriptional regulators, including BRD4 and SC35. Notably, RNA-FISH assays demonstrated that lnc-BARTs co-localize with BRD4 and SC35 complexes in nuclear speckles, with these complexes being disrupted by treatment with JQ1, a BRD4 competitive inhibitor. RNA immunoprecipitation and RNA pulldown assays confirmed that lnc-BARTs bind to BRD4. ATAC sequencing analysis and transcriptome analysis further demonstrated that knockdown of BARTs in the EBV-harboring NPC cell line, C666-1, resulted in globally reduced chromatin accessibility downregulation of oncogenes like MYC and BCL2. In addition, ChIP sequencing analysis revealed that lnc-BARTs interfere PolII phosphorylation on promoters of genes. Our findings suggest that EBV lnc-BARTs are involved in epigenetic modulation of host gene expression through functional interaction with elongation regulatory machinery to maintain EBV latency and drive tumorigenesis in NPC.

Citation Format: LIU JIAYAN, Bobo Wing-Yee Mok, Songtao He, Honglin Chen. Oncogenic role of Epstein-Barr virus lnc-BARTs in EBV associated tumors. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3749.
Abstract 3750: miR-590-3p inhibits multiple oncogenic nodes within the TGFBR2:SMAD2/3 pathway in recurrent GBM cells
Authors: Sall Sophie , Korleski Jack , Johnson Amanda , Johnson Maya , Lopez-Bertoni Hernando
Published: April 2023

Glioblastoma (GBM) is the most lethal and aggressive primary brain malignancy with high recurrence rates and virtually no long-term survival. Despite our expanding knowledge regarding GBM at the genomic/molecular level, we still don’t fully comprehend the molecular mechanisms responsible for GBM recurrence. Current knowledge implicates tumor-propagating Glioma Stem Cells (GSCs) in the evolution of treatment resistance and tumor recurrence. Understanding these cellular/molecular events will inform strategies for preventing and/or treating recurrent GBM (rGBM). Gene set enrichment analysis (GSEA) of RNA sequencing datasets obtained from GSCs and clinical rGBM specimens identified TGFBR2 signaling as a high frequency and potentially targetable pathway in rGBM. We show that SMAD2/3 signaling, a downstream effector of TGFBR2, is enriched in rGBM and that patients with elevated TGFBR2 have statistically shorter long-term survival outlooks. The functional relevance of these findings was supported using ITD1, a selective TGFBR2 inhibitor, which decreased the GSC phenotype and cell viability of cells derived from clinical rGBM (rGBM cells), while simultaneously re-sensitizing them to temozolomide (TMZ) in-vitro. Since GBM is known to efficiently develop resistance to receptor-targeting monotherapies, we sought to simultaneously target multiple putative oncogenic drivers downstream of TGFBR2. To achieve this, we applied an unbiased miRNA-based network analysis that identified miR-590-3p as an inhibitor of SMAD2/3 signaling at multiple nodes and thus a potential tumor suppressor in rGBM. Transgenic miR-590-3p robustly decreased the expression of >30 putative oncogenes, reduced the GSC phenotype and cell viability, as well as re-sensitized rGBM cells to TMZ. These results predict that blocking TGFBR2 signaling will negatively impact the tumor phenotype of rGBM as well as its GSC capacity. Ongoing directions for this research include comparing the efficacy of ITD1 monotherapy with miR-590-3p therapy in rGBM models in-vivo. These results identify a significant role of TGFBR2 signaling in both TMZ resistance and the GSC phenotype in rGBM and provide a miRNA-based strategy for simultaneously targeting multiple oncogenic nodes within the TGFBR2 and potentially other oncogenic signaling pathways.

Citation Format: Sophie Sall, Jack Korleski, Amanda Johnson, Maya Johnson, Hernando Lopez-Bertoni. miR-590-3p inhibits multiple oncogenic nodes within the TGFBR2:SMAD2/3 pathway in recurrent GBM cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3750.
Abstract 3760: MicroRNA-1 run down the growth and metastasis of small cell lung cancer
Authors: Khan Parvez , Siddiqui Jawed A. , Maurya Shailendra Kumar , Mirzapoiazova Tamara , Kshirsagar Prakash G. , Venkata Ramakanth Chirravuri , Chaudhary Sanjib , Kanchan Ranjana , Perumal Naveenkumar , Fatima Mahek , Khan Md Arafat , Rehman Asad Ur , Lakshmanan Imayavaramban , Mahapatra Sidharth , Kulkarni Prakash , Ganti Apar Kishor , Jain Maneesh , Salgia Ravi , Batra Surinder Kumar , Nasser Mohd Wasim
Published: April 2023

Small cell lung cancer (SCLC) is a highly aggressive and metastatic lung cancer subtype with universal relapse and poor prognosis. The lack of potential drug targets limits targeted therapies for SCLC patients. To track down the potential therapeutic molecules in SCLC, we performed micro-RNA sequencing from the serum samples of SCLC patients and compared with the bulk RNA-sequencing data from SCLC tumor tissues. A consistent downregulation of microRNA-1 (miR-1) was observed in the SCLC patient serum samples, cell lines, and tumor tissues compared to their matched normal control. Overexpression of miR-1 in SCLC cell lines decreased cell growth and oncogenic signaling. Metastatic studies using the intracardiac injection model of SCLC cell lines showed that miR-1 overexpression decreases distant organ metastasis. Interestingly, the loss of function studies using miR-1Zip/sponging showed increased tumorigenesis and metastasis in SCLC subcutaneous and intracardiac xenografts. Mechanistic investigations revealed the CXCR4/FOXM1/RRM2 axis as a unique downstream target of miR-1 in SCLC. We found that FOXM1 transcriptionally regulates the RRM2 expression by directly binding to its promoter site, and miR-1 modulates these interactions through CXCR4. The results of the present study provided a strong preclinical rationale that miR-1 has a high potential for developing innovative SCLC therapies.

Citation Format: Parvez Khan, Jawed A. Siddiqui, Shailendra Kumar Maurya, Tamara Mirzapoiazova, Prakash G. Kshirsagar, Ramakanth Chirravuri Venkata, Sanjib Chaudhary, Ranjana Kanchan, Naveenkumar Perumal, Mahek Fatima, Md Arafat Khan, Asad Ur Rehman, Imayavaramban Lakshmanan, Sidharth Mahapatra, Prakash Kulkarni, Apar Kishor Ganti, Maneesh Jain, Ravi Salgia, Surinder Kumar Batra, Mohd Wasim Nasser. MicroRNA-1 run down the growth and metastasis of small cell lung cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3760.
Abstract 3774: MiR-34b promotes cellular senescence and ROS generation in human cervical cancer cells
Authors: Sindhu K J , Karunagaran Devarajan
Published: April 2023

Background: Cervical cancer is one of the most common cancers in women worldwide, particularly in low- and middle-income countries. Due to low surveillance and late detection, it is one of the major health issues leading to high mortality rates. MicroRNA-34 family (miR-34a, b, c) is thought to be tumor suppressive in several cancers but the mechanistic basis is not clear.

Methods: Stable cell lines were generated with inducible hsa-miR-34b lentiviral vector from Dharmacon and maximal time and dose for induction of miR-34b with doxycycline were determined. Cell viability studies on HeLa, SiHa and C33A were investigated by MTT assay. Acridine orange/Ethidium bromide (AO/EB), senescence associated β-galactosidase (SA- β gal) assays for apoptosis and senescence and assessment of DNA damage (γH2AX) were performed. Total reactive oxygen species (ROS), superoxide, hydroxyl and peroxynitrite and H2O2 radicals were quantitated by DCFDA, DHE, HPF dyes and pHyper-dMito plasmid, respectively.

Results: Overexpression of miR-34b reduced cell viability in cervical cancer cell lines except SiHa. Further investigation by AO/EB staining revealed no significant increase in the proportion of apoptotic cells on overexpression of miR-34b. Analysis of SA- β gal on overexpression of miR-34b revealed an increase in the proportion of senescent population in all 3 cell lines. Increased DNA damage is also observed in agreement with an increase in cellular senescence. In addition, an increase in oxidative stress was observed in miR-34b overexpressing cell lines as total ROS was elevated in all 3 cell lines with increased superoxide, hydroxyl and peroxynitrite and H2O2 radicals in HeLa and C33A while SiHa showed increased levels of H2O2 radicals with no significant change in other radicals.

Conclusions: Overexpression of miR-34b can promote an increase in cellular senescence and oxidative stress in cervical cancer. The differential action in different cell lines may be due to the difference in expression of miR-34b in these cell lines. Our results highlight the potential of miR-34b to be used for therapeutic intervention in cervical cancer.

Citation Format: K J Sindhu, Devarajan Karunagaran. MiR-34b promotes cellular senescence and ROS generation in human cervical cancer cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3774.
Abstract 3782: Targeting cancer cells using folate conjugated to a fully modified version of miR-34a (FolamiR-34a) to produce enhanced and sustained anti-tumor activity
Authors: Iyer Shreyas Ganesan , Abdelaal Ahmed M. , Sohal Ikjot Singh , Kasireddy Sudarsan R. , Kasinski Andrea L.
Published: April 2023

Due to the pleiotropic nature of miR-34a, including its ability to downregulate multiple genes that drive resistance to currently used anti-cancer therapies, we hypothesize that the best use of miR-34a in a clinical setting would be in combination with standard-of-care treatments. For in vivo use, such a molecule would necessitate the following: i) a stabilized version of miR-34a that can withstand the harsh environment in circulation and intracellular nucleases, and ii) a robust, specific, and safe delivery vehicle. With regard to stability, we successfully generated the first fully modified version of miR-34a. This new chemically modified molecule is over 400-fold more stable than the previously used partially modified version and induces enhanced and sustained target gene repression. To assess in vivo activity of fully modified miR-34a requires a suitable delivery vehicle. Indeed, while various approaches have been used to restore miR-34a in tumors, clinically relevant mechanisms for delivery of miR-34a have been a challenge due to poor tumor uptake, unfavorable bioavailability, and unwanted toxicity. Previously, we determined that a partially modified version of miR-34a can be delivered specifically and robustly to cancer cells in a targeted, vehicle-free manner through direct conjugation to folate, a ligand of the high-affinity folate receptors. Thus, we conjugated our fully modified miR-34a (FM-miR-34a) to folate generating FM-FolamiR-34a. Following in vivo delivery of FM-FolamiR-34a to mice with breast cancer xenografts we observed enhanced and sustained target gene repression, in comparison to our first-generation partially modified folate-miR-34a conjugate (FolamiR). Critical miR-34a target genes involved in promoting resistance, including MET, AXL, and CD44 were downregulated over 90% for at least 120 hours following a single 1.5 nmol dose of FM-FolamiR-34a. Our final objective is to evaluate FM-FolamiR-34a in combination with standard-of-care agents in vivo.

Citation Format: Shreyas Ganesan Iyer, Ahmed M. Abdelaal, Ikjot Singh Sohal, Sudarsan R. Kasireddy, Andrea L. Kasinski. Targeting cancer cells using folate conjugated to a fully modified version of miR-34a (FolamiR-34a) to produce enhanced and sustained anti-tumor activity. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3782.
Abstract 3783: Role of microRNA 28-3p in prostate cancer progression
Authors: Sreekumar Amritha , Saini Sharanjot
Published: April 2023

Prostate cancer (PCa) is a leading cause of cancer incidence and mortality among men. Prostate cancer is driven by androgens acting via androgen receptor (AR). Therefore, this cancer is treated with androgen deprivation therapy (ADT) initially. However, the cancer rapidly evolves to be resistant to ADT and progresses to a more invasive stage referred to as ‘Castration Resistant prostate cancer’ (CRPC). CRPC is treated with second generation of AR pathway inhibitors such as Enzalutamide and Abiraterone. These treatments are effective initially. However, drug resistance develops in a significant fraction of patients and the cancer undergoes ‘neuroendocrine trans-differentiation (NED) to a lethal variant called ‘neuroendocrine prostate cancer’ (NEPC). As a result of NED, PCa cells express neuronal markers such as synaptophysin, chromogranin A and enolase. The molecular basis of NED is not yet fully defined. With a focus on identifying the role of microRNAs (miRNAs) in NEPC, we performed small RNA sequencing in CRPC tumors with and without NED. This sequencing identified miR-28-3p to be significantly downregulated in CRPC-NE samples as compared to CRPC-adenocarcinomas (CRPC-Adeno). In view of this, we examined the role of this miRNA in NEPC. Analyses of TCGA data of prostate adenocarcinomas suggest that miR 28-3p has an oncogenic role in primary prostate tumors. However, its expression declines in tumors with increasing Gleason score. We profiled the expression of miR-28-3p in patient-derived xenograft models and clinical CRPC-NE and CRPC-Adeno tissues by real time PCR. Our profiling showed a trend towards downregulation with increased NED. Basal expression of miR 28-3p in various prostate cancer cell lines showed an elevated level in androgen dependent cell lines whereas significantly less expression in NEPC cell lines, LASCPC-01 and NCI-H660. In this study, we generated PC3 cell line that stably expresses miR-28 for understanding its functional role in regulating PCa. Preliminary functional assays including cell viability assay, cell cycle studies and invasion and migration assay suggest a tumor suppressor role of miR-28-3p in advanced prostate cancer. In conclusion, our data shows that miR 28-3p potentially has a biphasic role in PCa, where it is oncogenic in early stages and acts as a tumor suppressor in late stage PCa.

Citation Format: Amritha Sreekumar, Sharanjot Saini. Role of microRNA 28-3p in prostate cancer progression. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3783.
Abstract 3821: Berberine and emodin synergistically suppress the EGFR signaling cascade by targeting LAMB3 in pancreatic ductal adenocarcinoma
Authors: XU CAIMING , SUI SILEI , Okuno Keisuke , Pascual-Sabater Silvia , Fillat Cristina , Goel Ajay
Published: April 2023

Background: Pancreatic cancer is one of the most devastating malignancies due to the development of intrinsic chemoresistance following chemotherapy. Extracellular matrix (ECM) proteins are intimately linked to cellular proliferation, invasion, and acquisition of chemoresistance in PDAC cells, making them promising therapeutic targets in this malignancy. Naturally occurring dietary botanicals, including berberine (BER) and emodin (EMO), have been shown to suppress ECM as one of the mechanism(s) for their anti-tumorigenic activity, along with their time-tested safety and cost-effectiveness. In addition, both BER and EMO are also known to induce apoptosis by modulating different pathways and regulating pro-apoptotic genes. Herein, we hypothesized that combined treatment with BER and EMO might exhibit synergistic anticancer efficacy by targeting the ECM and apoptotic pathways in PDAC cells.

Methods: We undertook genomewide transcriptomic profiling analysis to identify critical ECM-related genes differentially expressed in PDAC. Subsequently, the TCGA dataset was analyzed to identify the prognostic significance of ECM-associated genes with overall survival (OS) and disease-free survival (DFS) in PDAC. A series of cell culture experiments were performed using PDAC cells, followed by their validation in patient-derived organoids to examine the synergistic anti-proliferative and chemopreventive effects of BER and EMO against PDAC.

Results: Transcriptomic profiling identified that LAMB3 expression was significantly upregulated in PDAC tissue (P < 0.01) and was significantly associated with poor OS and DFS in PDAC patients (P < 0.01). The combination of BER and EMO displayed superior synergistic anti-tumor potential in PDAC cells vs. individual compounds, as revealed by cell proliferation, clonogenicity, migration, and invasion assays. The combination of BER and EMO also altered the expression of key proteins involved in cellular apoptosis, epithelial-mesenchymal-transition, and EGFR/ERK//AKT growth factor signaling pathways. Finally, these findings were successfully validated in PDAC patient-derived 3D organoids.

Conclusions: We provide the first evidence that combined treatment with berberine and emodin exerts synergistic anti-cancer activity in PDAC, primarily regulated through the LAMB3-mediated interaction with other members of the EGFR-signaling pathway.

Citation Format: CAIMING XU, SILEI SUI, Keisuke Okuno, Silvia Pascual-Sabater, Cristina Fillat, Ajay Goel. Berberine and emodin synergistically suppress the EGFR signaling cascade by targeting LAMB3 in pancreatic ductal adenocarcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3821.
Abstract 3823: Therapeutic potential of plant-derived nanovesicles for neuroendocrine prostate cancer
Authors: Sreekumar Amritha , Simmons Matthew , Lee Tae Jin , Sharma Ashok , Saini Sharanjot
Published: April 2023

Background: Neuroendocrine prostate cancer (NEPC) is a highly lethal variant of prostate cancer (PCa) that often emerges after androgen receptor (AR)-targeted therapies such as enzalutamide and abiraterone. NEPC arises via trans-differentiation of prostate adenocarcinomas to neuronal lineage, a process referred to as ‘neuroendocrine trans-differentiation’ (NED), wherein prostate cancer cells show an altered expression of lineage markers such as decreased expression of AR and increased expression of neuronal markers. Currently, there is a lack of effective targeted therapies for NEPC. Current treatment options are limited to highly toxic platinum-based drugs. Hence, there is an urgent need to develop novel treatment strategies to treat NEPC. The focused objective of this study is to develop novel, non-toxic therapeutic intervention against NEPC. Towards this, we exploited the potential of plant-derived nanovesicles/extracellular vesicles as a novel therapeutic. Extracellular vesicles (EVs) are lipid-bilayer-delimited particles that are released from almost all types of cells, including plant cells, typically between 30-150 nm in size.

Methods: EVs/nanovesicles were isolated from plant-derived sources by ultracentrifugation. Isolated nanovesicles were characterized by Nanoparticle Tracking Analyses and electron microscopy. After characterization, the effects of nanovesicles were tested in NEPC cell lines in vitro. Effects on cell viability and apoptosis were assessed by MTS assay and flow cytometry, respectively. To understand the mechanistic basis of EV induced alterations, next generation RNA sequencing was performed in control vs EV treated NCI-H660 cells on Illumina HiSeq platform. Significant targets were further validated by real time PCR and Western blot analyses.

Results: Plant-derived nanovesicles reduced viability and induced apoptosis in NEPC cell lines. Genes involved in ECM-receptor interaction, focal adhesion, proteoglycans in cancer and small cell lung cancer genes were significantly impacted by these vesicles in NEPC cell line. Remarkably, nanovesicles led to significantly attenuated levels of key proneural transcription factors including ASCL1, BRN2 and SOX2. In addition, neuronal markers ENO2 and NCAM1 were downregulated suggesting that treatment with nanovesicles reverse the ‘cardinal’ genetic alterations that drive NEPC.

Conclusion: Plant-derived nanovesicles can be employed as a novel treatment modality in neuroendocrine prostate cancer.

Citation Format: Amritha Sreekumar, Matthew Simmons, Tae Jin Lee, Ashok Sharma, Sharanjot Saini. Therapeutic potential of plant-derived nanovesicles for neuroendocrine prostate cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3823.
Abstract 3841: Development of p300-targeting PROTAC degraders with enhanced selectivity and onset of degradation
Authors: Marsh Graham P. , Goggins Sean , Bosnakovski Darko , Kyba Michael , Ojeda Samuel , Harrison Drew A. , Ott Christopher J. , Maple Hannah J.
Published: April 2023

CREB-binding protein (CBP, CREBBP, KAT3A) and E1A-binding protein (EP300, p300, KAT3B) are paralogous multi-domain proteins that act as chromatin regulators and transcriptional co-activators. They contain a histone acetyltransferase (HAT) domain that catalyzes the histone H3, lysine 27 acetylation (H3K27ac) mark at regulatory elements such as enhancers and promoters. Transcription factors associate with stretches of H3K27ac marks (known as ‘super-enhancer’ elements) and result in gene transcription that ultimately establishes cell identity and fate. They are implicated in cancer pathology, and small molecule inhibition of the bromodomain (BRD) or HAT domain of CBP/p300 are considered promising therapeutic strategies for a number of cancer types.

CBP and p300 are highly homologous but have distinct roles that have to date been hard to delineate, since small molecule inhibitors developed to date are unable to selectively target each protein independently. Additionally, small molecule inhibitors that target individual domains are unable to entirely abrogate the full functionality of CBP/p300. A bromodomain-recruiting dual CBP/p300 PROTAC Degrader ‘dCBP1’ was therefore recently developed to provide a chemical tool to explore the phenotypic consequences of CBP/p300 chemical knockdown. A further study demonstrated that it is possible to degrade p300 with some selectivity by converting a CBP/p300 dual HAT-domain inhibitor into a PROTAC, called ‘JQAD1’.

We have used a different HAT-domain recruiting ligand to develop novel PROTACs that elicit proteasome-mediated degradation of p300 with significantly enhanced selectivity over CBP, compared with JQAD1. We additionally demonstrate a faster onset of degradation for lead PROTAC molecules and present data exploring the consequences of selective p300 degradation in CIC-DIX4 sarcoma.

Citation Format: Graham P. Marsh, Sean Goggins, Darko Bosnakovski, Michael Kyba, Samuel Ojeda, Drew A. Harrison, Christopher J. Ott, Hannah J. Maple. Development of p300-targeting PROTAC degraders with enhanced selectivity and onset of degradation. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3841.
Abstract 3925: JunB regulates expression of HPV genes in head and neck cancer
Authors: Rehmani Hina , Schrank Travis P. , Issaeva Natalia , Yarbrough Wendell G.
Published: April 2023

The incidence of HPV-positive head and neck squamous cell carcinoma (HNSCC) is now being considered an epidemic in the US and Western Europe as rates have surpassed those for cervical cancer. For approximately 14,400 patients per year in the US, initial therapy is aggressive and often results in adverse lifelong side effects such as difficulty swallowing and speaking. Despite having a higher cure rate than HPV-negative HNSCC, the recurrence rate is still approximately 30%. Therefore, new treatment options need to be available for these relapsed patients. Our lab was prompted to explore demethylation as a therapeutic option as HPV-positive HNSCC have a more hypermethylated genome than HPV-negative cancers. 5-azacytidine (5-aza) is a synthetic cytidine analog that causes DNA demethylation by trapping methyltransferases to chromatin; it is FDA-approved for the treatment of myelodysplasia and acute myeloid leukemia. Our lab found that low doses of 5-aza delayed HPV-positive xenograft tumor growth and that HPV-positive tumor samples from patients treated with 5-aza in a window trial had increased apoptosis. They also observed a marked downregulation of HPV gene expression after 5-aza. Decreased HPV E6 expression, followed by reactivation of tumor suppressor p53, induced p53-dependent apoptosis in HPV-positive HNSCC. To further explore the mechanism of this sensitivity to 5-Aza, we first determined that 5-aza regulates the transcription of HPV genes, but not the stability of HPV transcripts. We found that the transcriptional regulation of HPV genes after 5-aza depends on the proto-oncogene JunB, a component of the transcription factor Activator Protein 1 (AP-1). Additionally, silencing of JunB abolished the expression of HPV E6/E7 genes and reactivated tumor suppressor p53 in HPV-positive HNSCC. Furthermore, we revealed that clonogenic survival of HPV-positive head and neck cancer cells is dependent on JunB expression. Our study exposes an important component of 5-Aza-associated sensitivity and toxicity in HPV-positive HNSCC and identifies a novel dependency on JunB, potentially providing a new rational targeted therapy.

Citation Format: Hina Rehmani, Travis P. Schrank, Natalia Issaeva, Wendell G. Yarbrough. JunB regulates expression of HPV genes in head and neck cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3925.