bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5545: Intestinal toxicity to CTLA-4 blockade driven by IL-6 and myeloid infiltration
Authors: Zhou Yifan , Medik Yusra B. , Patel Bhakti , Zamler Daniel B. , Chen Sijie , Chapman Thomas , Schneider Sarah , Babcock Rachel L. , Chrisikos Taylor T. , Kahn Laura M. , Dyevoich Allison M. , Park Elizabeth M. , Cogdill Alexandria P. , Johnson Daniel H. , Johnson Sarah B. , Wani Khalida M. , Ledesma Debora A. , Hudgens Courtney W. , Wang Jingjing , Khan Md Abdul Wadud , Joon Aron Y. , Peng Weiyi , Li Haiyan S. , Arora Reetakshi , Tang Ximing , Raso Maria Gabriela , Zhang Xuegong , Foo Wai Chin , Tetzlaff Michael T. , Diehl Gretchen E. , Clise-Dwyer Karen , Whitley Elizabeth M. , Gubin Matthew M. , Allison James P. , Hwu Patrick , Ajami Nadim J. , Diab Adi , Wargo Jennifer A. , Watowich Stephanie S.
Published: June 2022

Immunotherapies such as anti-CTLA-4 immune checkpoint blockade (ICB) have revolutionized cancer treatment, yet quality of life and continuation of therapy can be constrained by off-target tissue damage or immune-related adverse events (irAEs). At present, there is limited understanding of irAE mechanisms, hampering development of approaches to mitigate their damage. We addressed this problem by generating animal models of intestinal irAE. Our results show that disruption of homeostatic immunity by genetic predisposition to intestinal inflammation or acute gastrointestinal infection sensitizes mice to anti-CTLA-4-mediated intestinal toxicity. Inflammation-prone mice treated with anti-CTLA-4 showed neutrophil accumulation, systemic interleukin-6 (IL-6) release, and dysbiosis. Significantly, IL-6 blockade combined with antibiotic treatment improved anti-CTLA-4 therapeutic efficacy and reduced intestinal irAEs. Immune signatures were validated in biopsies from patients who developed colitis during ICB, supporting the utility of our models. This study provides new pre-clinical models, mechanistic insight into irAEs, and potential approaches to enhance ICB efficacy while mitigating irAEs.

Citation Format: Yifan Zhou, Yusra B. Medik, Bhakti Patel, Daniel B. Zamler, Sijie Chen, Thomas Chapman, Sarah Schneider, Rachel L. Babcock, Taylor T. Chrisikos, Laura M. Kahn, Allison M. Dyevoich, Elizabeth M. Park, Alexandria P. Cogdill, Daniel H. Johnson, Sarah B. Johnson, Khalida M. Wani, Debora A. Ledesma, Courtney W. Hudgens, Jingjing Wang, Md Abdul Wadud Khan, Aron Y. Joon, Weiyi Peng, Haiyan S. Li, Reetakshi Arora, Ximing Tang, Maria Gabriela Raso, Xuegong Zhang, Wai Chin Foo, Michael T. Tetzlaff, Gretchen E. Diehl, Karen Clise-Dwyer, Elizabeth M. Whitley, Matthew M. Gubin, James P. Allison, Patrick Hwu, Nadim J. Ajami, Adi Diab, Jennifer A. Wargo, Stephanie S. Watowich. Intestinal toxicity to CTLA-4 blockade driven by IL-6 and myeloid infiltration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5545.
Abstract 5558: Discovery of a novel Claudin 6 X 4-1BB bispecific antibody with potent anti-tumor activity through conditional 4-1BB activation
Authors: Li Jian , Jiang Wenqing , Liu Yan , Wang Zhengyi , Chen Xi , Guo Taylor B.
Published: June 2022

Background Claudin 6 (CLDN6) is a tight junction transmembrane protein normally only expressed during embryonic development, but is aberrantly expressed in a variety of tumors, including ovarian cancer, testicular cancer, hepatocellular and lung adenocarcinoma. Here, we generated a CLDN6 X 4-1BB bispecific antibody (BsAb) which could conditionally activate T cells through 4-1BB stimulation upon CLDN6 engagement, positioning it as a potential novel immunotherapy for ovarian cancer and other CLDN6 positive tumors.

Methods CLDN6 X 4-1BB BsAb was evaluated for its antigen binding through cell-based binding assay. In vitro function of the antibody was confirmed in a 4-1BB signaling reporter assay and primary human PBMC assay. In vivo efficacy of the antibody was further demonstrated in 4-1BB humanized syngeneic mouse model. Ex vivo analysis of tumor infiltrating and peripheral immune cells was conducted by FACS. Safety parameters such as liver enzymes and pathology upon antibody administration were also assessed.

Results CLDN6 X 4-1BB BsAb showed strong binding to several ovarian cancer cell lines with different levels of CLDN6 expression. Functional evaluation of CLDN6X4-1BB BsAb indicated that the activation of 4-1BB signaling was dependent on CLDN6 expression on tumor cells and the activity was stronger than reference 4-1BB monoclonal antibody urelumab. In a humanized 4-1BB mouse model, CLDN6X4-1BB BsAb showed tumor growth inhibition superior to the combination of anti-CLDN6 and anti-4-1BB monospecific antibodies, and the treatment effect was associated with an increase in tumor infiltrating CD45 and CD8 cells as well as CD8/Treg ratio. From the safety perspective, there were no significant changes in liver enzymes or liver histopathology following repeated BsAb administration, suggesting little risks for liver toxicity commonly induced by other 4-1BB agonist antibodies.

Conclusions We have successfully generated a novel CLDN6-targeted 4-1BB bispecific antibody which could induce potent 4-1BB stimulation and anti-tumor activity in a CLDN6-dependent manner while minimizing the risk of liver toxicity. Taken together, these data support further development of CLDN6 X 4-1BB bispecific antibody towards IND and clinical trial in 2022.

Citation Format: Jian Li, Wenqing Jiang, Yan Liu, Zhengyi Wang, Xi Chen, Taylor B. Guo. Discovery of a novel Claudin 6 X 4-1BB bispecific antibody with potent anti-tumor activity through conditional 4-1BB activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5558.
Abstract 5562: Development of a TERT-specific peptide/adjuvant vaccine in C57BL/6 mice
Authors: Marshall Jason D. , Song Yurong , Zarkesh Hamid , Matthews Rebecca L. , Sanders Chelsea , Difilippantonio Simone , Pinto Ligia A. , Sei Shizuko , Shoemaker Robert H.
Published: June 2022

Telomerase plays a vital role in cell senescence and cellular replication and has been described as a leading regulator in several human cancers, including prostate, thyroid, breast, colon, and bladder cancer. Telomerase is responsible for elongating telomere length and prolonging cellular lifespan as well as acting as a transcriptional modulator in cancer signaling pathways. Because of its enhanced expression in primary tumor cells as well as incipient tumor-initiating stem cells and with limited distribution in normal somatic cells, the catalytic component of telomerase, TERT (telomerase reverse transcriptase), is regarded as a high-impact target for immunotherapeutic agents and vaccines. In order to derive a mouse TERT (mTERT)-specific vaccine which could be useful in a preventive approach, we implemented an epitope-mapping stratagem by which pools of 30-mer peptides overlapping by 5 spanning the entire mTERT sequence were used to immunize C57BL/6 mice. Several immunogenic peptides were identified by matrixed peptide pool IFN-ɣ ELISPOT screening in a 2-part process that first identified positive pools, then identified individual peptides. 15-mer and 31-mer versions of the top 7 immunogenic mTERT peptides were synthesized and used as a peptide pool combined separately with several adjuvants to optimize immunogenicity. Results suggested a peptide sequence-specific preference for TLR3-mediated Hiltonol versus TLR9-mediated CpG-based adjuvants. In addition, the majority of T cell responses specific to the TERT peptides was identified through flow cytometry as belonging to the CD4 compartment, although one class I-restricted epitope was also identified. Multifunctional CD4+ T cells expressing IFN-ɣ, TNF-α, IL-2, and CD107a were identified specific to several mTERT peptides. In vivo cytotoxic effects exerted on TERT peptide pool-loaded target cells were also uncovered that were specific to a CpG-adjuvanted version of the vaccine. Finally, multiple versions of the mTERT peptide/adjuvant vaccine with highest immunogenicity scores are being tested in a syngeneic graft mouse model using subcutaneous implantation of lung cancer-derived SPON10 cells expressing mTERT. If proven efficacious, these results will support the feasibility of a TERT peptide/adjuvant approach for prophylactically engendering broad antitumor immunity to TERT-expressing cancers. Funded by NCI Contract No. HHSN261200800001E

Citation Format: Jason D. Marshall, Yurong Song, Hamid Zarkesh, Rebecca L. Matthews, Chelsea Sanders, Simone Difilippantonio, Ligia A. Pinto, Shizuko Sei, Robert H. Shoemaker. Development of a TERT-specific peptide/adjuvant vaccine in C57BL/6 mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5562.
Abstract 5580: Incorporation of pro-memory transcription factors in fourth generation CARs enhances CAR T cell immunotherapy against solid tumors in an immunocompetent murine model
Authors: Reed Steven J. , Tower Samantha J. , Toumi Ryma , Kalia Vandana , Sarkar Surojit
Published: June 2022

A major obstacle in current T cell-based immunotherapy against solid tumors is the widely observed T cell exhaustion and loss of functionality within the tumor microenvironment (TME). We, and others, have demonstrated that chronic antigenic signaling is the predominant factor that drives TCR tumor-reactive, and CAR T cell exhaustion in the TME. To combat this exhaustion, we have engineered CD19-targeted third generation CAR constructs to express pro-memory transcription factors associated with longevity, polyfunctionality and/or enhanced responsiveness to immune checkpoint blockade in cancer immunotherapy. Using an immunocompetent murine model of syngeneic solid tumors expressing truncated human-CD19 (hCD19t), we demonstrate that ectopic expression of pro-memory transcription factors in the 4th generation transcription factor-CARs (TF-CARs) augments CAR T cell therapeutic efficacy against solid tumors. Amongst CAR T cells recovered from established solid tumors, the 4th generation TF-CAR T cells retained a memory-precursor effector (MPEC) T cell like phenotype, while the 3rd generation CAR T cells largely displayed a terminally exhausted phenotype (TEx). Importantly, the inclusion of select pro-memory transcription factors did not compromise CAR T cell proliferation or expression of the effector cytokines IFN-γ and TNFα following restimulation. In addition to superior control of primary tumors, the TF-CAR T cells instilled greater long-term protection from tumor relapse in mice, which cleared primary tumors (6/7) compared to 3rd generation CAR T cells (3/7). Collectively, these data present incorporation of pro-memory transcription factors as an attractive engineering strategy to intrinsically combat CAR T cell exhaustion in the TME and promote long-term CAR T cell memory and protection from tumor relapse.

Citation Format: Steven J. Reed, Samantha J. Tower, Ryma Toumi, Vandana Kalia, Surojit Sarkar. Incorporation of pro-memory transcription factors in fourth generation CARs enhances CAR T cell immunotherapy against solid tumors in an immunocompetent murine model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5580.
Abstract 5585: Inhibition of CSF1R enhances the antitumor efficacy of DC derived exosomes by modulating immunosuppressive tumor microenvironment
Authors: Barnwal Anjali , Bhattacharyya Jayanta , Ateeq Bushra
Published: June 2022

Dendritic cell (DC) derived exosomes (Dex) provide many advantages over DC vaccines such as cost effectiveness, stability, sensitivity to the systemic microenvironment. Though, Dex showed better therapeutic outcome in murine models, however, desired outcome was not achieved in clinical trials as it failed to induce robust immunity to modulate the immunosuppressive tumor microenvironment (TME). Colony stimulating factor-1 (CSF-1) binds to its receptor (CSF-1R) and recruits tumor associated macrophages (TAMs) and myeloid derived suppressor cells (MDSCs) in the TME which eventually creates the tumor immunosuppressive. Hence, in this study we used PLX-3397, a small molecule inhibitor of CSF-1R to enhance the antitumor efficacy of Dex. In a syngenic B16-F10murine melanoma model, we found that the combination treatment delayed the tumor growth and improved the survival compare to the mono therapy. In TME, the combination treatment significantly depleted the TAMs and MDSCs and increased the infiltration of lymphocytes (TILs). Additionally, Th1 population were found significantly higher in tumor as well as in spleen with mice received both Dex and PLX3397. In conclusion, PLX-3397 enhanced the in vivo antitumor efficacy of Dex by modulating the immunosuppressive microenvironment in tumor.

Citation Format: Anjali Barnwal, Jayanta Bhattacharyya, Bushra Ateeq. Inhibition of CSF1R enhances the antitumor efficacy of DC derived exosomes by modulating immunosuppressive tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5585.
Abstract 5589: BYON4228 is a pan-allelic SIRPα antibody that potentiates killing of antibody-opsonized tumor cells and lacks binding to T cells
Authors: van Helden Mary , Zwarthoff Seline , Olsman Hugo , Paradé Marc , Mattaar Ellen , de Laat Karin , Lodewijks Imke , Boersema Paul , Driessen-Engels Lilian , Sanderink Jorien , Kappers Wendy , van den Dobbelsteen Diels , Ubink Ruud , Arends Roel , Rouwendal Gerard , Verheijden Gijs , van der Lee Miranda , Dokter Wim , Van den Berg Timo
Published: June 2022

Preclinical data have established CD47-SIRPα interactions as a myeloid immune checkpoint in cancer, which is corroborated by preliminary evidence from the first clinical studies with CD47 blockers. However, the ubiquitously expressed CD47 mediates functional interactions with other ligands as well, and therefore targeting of the primarily myeloid cell-restricted inhibitory immunoreceptor SIRPα may represent a better strategy. Here, we present preclinical results on a novel clinical candidate, BYON4228. BYON4228 is an antibody directed against SIRPα and recognizes both of the common allelic variants of human SIRPα which maximizes its potential clinical application in the broad human population. Notably, in contrast to several other anti-SIRPα antibodies in development, BYON4228 does not recognize the closely related T cell-expressed SIRPγ that has been reported to mediate interactions with CD47 as well, which are known to be instrumental in T cell extravasation and activation. BYON4228 binds to the N-terminal part of SIRPα and its epitope overlaps with the CD47-binding site. BYON4228 therefore prevents binding of CD47 to SIRPα and thus blocks inhibitory signaling through the CD47-SIRPα axis. Functional studies show that BYON4228 potentiates both macrophage- and neutrophil-mediated elimination of hematologic and solid cancer cells in vitro in the presence of several different tumor targeting antibodies like trastuzumab, rituximab, daratumumab and cetuximab, illustrating the broad potential clinical benefit and application of BYON4228. Single intravenous infusion of up to 100 mg/kg BYON4228 to male and female cynomolgus monkeys was well tolerated and did not elicit any adverse effects. Collectively, this defines BYON4228 as a pan-allelic anti-SIRPα antibody without T cell SIRPγ recognition that promotes the destruction of antibody-opsonized cancer cells. Clinical studies are planned to start in 2022.

Citation Format: Mary van Helden, Seline Zwarthoff, Hugo Olsman, Marc Paradé, Ellen Mattaar, Karin de Laat, Imke Lodewijks, Paul Boersema, Lilian Driessen-Engels, Jorien Sanderink, Wendy Kappers, Diels van den Dobbelsteen, Ruud Ubink, Roel Arends, Gerard Rouwendal, Gijs Verheijden, Miranda van der Lee, Wim Dokter, Timo Van den Berg. BYON4228 is a pan-allelic SIRPα antibody that potentiates killing of antibody-opsonized tumor cells and lacks binding to T cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5589.
Abstract 5605: BH3120: A novel bispecific antibody targeting 4-1BB and PD-L1 with well balanced efficacy and safety profiles
Authors: Xu Jiangcheng , Liu Yang , Wang Jing , Fan Fei , Gu Haitao , Zhang Lanxin , Wang Jun , Song Ding , Guo Ailong , Zhang Hongjuan , Su Kaixuan , Su Jiaojiao , Li Lijuan , Cai Jingmei , Zhang Aihong , Liu Jiawang , Lee Kyoungwoo
Published: June 2022

4-1BB (CD137, TNFSF9) is a promising co-stimulatory signaling mediator of T cells and NK cells, and agonistic monoclonal antibodies targeting 4-1BB are under clinical investigations aiming to observe sufficient and prolonged anti-tumor efficacy. However, these trials have resulted in limited efficacy or safety, and different bispecific approaches are being explored to improve the profiles. BH3120, a bivalent bispecific antibody generated by Pentambody(TM) platform targeting 4-1BB and PD-L1 simultaneously, demonstrates strong and prolonged antitumor efficacy as monotherapy in in vivo studies, and favorable safety profiles up to 200mg/kg/dose in non-human primates. Moreover, combination of BH3120 with an immune checkpoint inhibitor shows synergistically enhanced anti-tumor efficacy. Supported by these results, IND enabling studies of BH3120 are on-going and clinical evaluations are planned from later in 2022.

Citation Format: Jiangcheng Xu, Yang Liu, Jing Wang, Fei Fan, Haitao Gu, Lanxin Zhang, Jun Wang, Ding Song, Ailong Guo, Hongjuan Zhang, Kaixuan Su, Jiaojiao Su, Lijuan Li, Jingmei Cai, Aihong Zhang, Jiawang Liu, Kyoungwoo Lee. BH3120: A novel bispecific antibody targeting 4-1BB and PD-L1 with well balanced efficacy and safety profiles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5605.
Abstract 5606: GlycoConnect™ immune cell engagers (GC™-ICEs). A non-genetic approach to targeted IL-15 immunotherapy
Authors: van Geel Remon , van Delft Floris
Published: June 2022

Engagement of T cell or NK cells to harness a patient’s immune system is a promising approach in immuno-oncology. An immunocytokine, i.e. a tumor-targeting antibody (fragment) genetically fused to an immunostimulatory cytokine, is specifically designed for this purpose. Fusion antibody-IL-15 immunocytokines, based on a variety of molecular architectures, are currently finding their way to the clinic with promising results. Here we demonstrate how GlycoConnect™, a site-specific conjugation technology anchoring on the native antibody glycan, can be applied for attachment of IL-15 without prior antibody engineering. The molecular architecture of the resulting immune cell engagers (ICEs) can be readily tailored to 2:2 or 2:1 ratio (anti-TAA:IL-15) to mitigate cytokine release syndrome. Moreover, we show how immunostimulatory activity can be regulated via linker design, either by tailoring of IL-15-antibody spacing or by generation of a conditionally active IL-15 format. Structural and functional studies will be presented to corroborate the architecture of these GC™-ICEs and in vitro and in vivo activity in a syngeneic mouse model.

Citation Format: Remon van Geel, Floris van Delft. GlycoConnect™ immune cell engagers (GC™-ICEs). A non-genetic approach to targeted IL-15 immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5606.
Abstract 5615: YH008, a PD-1-CD40 bispecific antibody, inhibits tumor growth in vivo through PD-1-dependent activation of CD40 signaling
Authors: Liu Baihong , Yang Hao , Hui Li , Yang Benny
Published: June 2022

PD-1/PD-L1 inhibition immunotherapy is very popular in cancer treatment and has become one of the most pursued therapeutic strategies in the field. Combination treatment using anti-PD-1/PD-L1 agents with other immunomodulators brings additional benefits, such as preventing refractory effects towards PD-1/PD-L1 antibodies, and better inhibitory effects on tumor growth. Biocytogen developed YH008, a tetravalent anti PD-1/CD40 Fc-silenced IgG1 bispecific antibody (BsAb) that agonizes CD40 in a PD-1-dependent manner. Previously, YH008 demonstrated dose-dependent inhibitory efficacy against B16F10 engrafted tumors in PD-1/CD40 double humanized mice (established by Biocytogen: B-hPD1/CD40). Interestingly, in humanized CD40 mice that do not express human PD-1 expression, YH008 did not show tumor inhibition activity against the MC38 engrafted tumor. This observation indicates that YH008 activates the CD40 pathway in a PD-1 dependent manner. When compared with an anti-PD-L1/CD40 BsAb, YH008 showed superior tumor growth inhibition (TGI) against MC38 engrafted tumors in a triple humanized PD-1/PD-L1/CD40 mouse model (B-hPD-1/hPD-L1/hCD40). YH008 was observed to promote the proliferation and activation of dendritic cells, as well as increase CD8+/Treg ratio in B16F10 tumor-infiltrating lymphocytes (TILs). Furthermore, YH008 showed a superior liver toxicity profile compared to a selicrelumab analog. At a high dose of 100mg/kg, YH008 did not elevate liver enzymes in the blood of B-hPD1/hCD40 mice. Similarly, no significant adverse events were observed in a cynomolgus dose-escalation study. YH008 is currently in pre-clinical development with anticipated IND application in 2022.

Citation Format: Baihong Liu, Hao Yang, Li Hui, Benny Yang. YH008, a PD-1-CD40 bispecific antibody, inhibits tumor growth in vivo through PD-1-dependent activation of CD40 signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5615.
Abstract 5617: A novel genetically modified oncolytic vaccinia virus selectively replicates in tumors to activate an inflammatory TME and induce tumor regression
Authors: Goenaga Anne-Laure , Wang I-Ming , Clay Bryan S. , Lang Susanne , Wang Annabel , Weady Peter , Pillai Smitha P.S. , Ram Sripad , Mitchell Leah , Eisenbraun Michael , Binder Joseph , Avidal Liliana Maruri , Kirn David , Hollingsworth Robert , Lees Clare
Published: June 2022

Oncolytic viruses (OVs) have been widely investigated as cancer immunotherapy platforms and are represented by a diverse group of DNA and RNA viruses. We are currently investigating a genetically modified oncolytic vaccinia virus as a best-in-class tumor-selective investigational product for the treatment of solid tumors. Specifically, the viral thymidine kinase (TK) has been deleted to enhance safety by greatly limiting replication in healthy tissues while taking advantage of relatively higher endogenous TK levels in tumors. In addition to tumor-selective replication, the oncolytic vaccinia virus encodes an IL-2 variant (IL-2v) protein, which diminishes preferential activation of immunosuppressive Treg cells while preserving activation of CD8+ and NK cells and avoiding toxicities associated with wild type IL-2. Using a murine surrogate of the oncolytic vaccinia virus, we assessed preclinical efficacy in multiple murine syngeneic tumor models demonstrating selective tumor localized replication resulting in tumor growth inhibition. Consistent with tumor selective virus replication, viral copy number and IL-2v transgene levels were increased and had prolonged expression in the tumors compared to the periphery. Intratumoral colocalization of the virus and IL-2v was confirmed by IHC and ISH, respectively. Tumor growth inhibition was associated with increases in tumor infiltrating CD8 and NK effector cells. Additionally, efficacy of the mouse surrogate virus was associated with systemic increases in circulating total CD8 and NK cells as well as pSTAT5+ CD8 and NK cells in the blood. In summary, we have demonstrated that arming a TK-deficient oncolytic vaccinia virus with an IL-2v transgene can effectively couple short-term destruction of tumor cells through oncolysis with the activation of anti-tumor immune response in the tumor microenvironment. These data support the study of this therapy in Phase 1 clinical trials.

Citation Format: Anne-Laure Goenaga, I-Ming Wang, Bryan S. Clay, Susanne Lang, Annabel Wang, Peter Weady, Smitha P.S. Pillai, Sripad Ram, Leah Mitchell, Michael Eisenbraun, Joseph Binder, Liliana Maruri Avidal, David Kirn, Robert Hollingsworth, Clare Lees. A novel genetically modified oncolytic vaccinia virus selectively replicates in tumors to activate an inflammatory TME and induce tumor regression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5617.
Abstract 5642: Discovery of SCR-8079, a novel and selective CDK2/4/6 inhibitor overcomes the resistance to CDK4/6 inhibition and demonstrates broad anti-tumor activities in breast cancers
Authors: Zhou Feng , Yang Guimei , Tang Feng , Zhang Yan , Yang Wenqing , Xue Liting , Chen Ping , Tang Renhong
Published: June 2022

The CDK4/6 inhibitor, palbociclib (PAL), significantly improves progression-free survival and overall survival in HR positive and HER2-negative breast cancer in combination either with letrozole or fulvestrant. However, resistance to the CDK4/6 inhibition inevitably develops. Preclinical models and clinical transcriptome specimen analysis disclosed that abnormal activation of Cyclin E/CDK2 due to CCNE gene amplification was one of the major reasons to CDK4/6 inhibition resistance. And inhibition of CDK2 either by gene knockdown of CCNE or by pharmaceutic approach rescued the sensitivity of resistant tumor cells to CDK4/6 inhibition. To overcome the resistance, a novel and selective CDK2/4/6 inhibitor, SCR-8079 was developed. In biochemical assay, SCR-8079 was demonstrated high potency on inhibiting CDK2/4/6 with IC50 of 3 nM, 1 nM and 2 nM, respectively. And SCR-8079 showed good selectivity over CDK1/9 isoforms (>60 selectivity folds). SCR-8079 demonstrated closed inhibitory activities both on CDK4/6 sensitive and resistant lines. In MCF-7, a breast cancer cell line sensitive to PAL, SCR-8079 potently inhibited Rb phosphorylation (IC50, 53 nM) and cell proliferation (IC50, 28 nM). Meanwhile, SCR-8079 showed high potency on inhibiting on the growth of OVCAR3, an ovarian cancer cell line with elevated CDK2 activation and resistance to PAL. SCR-8079 inhibited Rb phosphorylation (IC50, 41 nM) and cell proliferation (IC50, 21 nM). In order to further mimic CDK4/6 resistance, a PAL resistant line (MCF-7R) was generated via induction of MCF-7 by gradient increased PAL. SCR-8079 potently inhibited MCF-7R cells growth (IC50, 3 nM) but PAL didn’t (IC50 >1 µM). Moreover, SCR-8079 showed high potency on growth inhibition in a broad of breast cancer cell lines, including HR-positive, Her2-positive and triple negative lines. SCR-8079 displayed good oral bioavailability in multiple pre-clinical species and robust anti-tumor activities both in OVCAR3 and MCF7 xenograft models. In summary, SCR-8079 is a selective CDK2/4/6 inhibitor, which overcomes the CCNE-mediated resistance to CDK4/6 inhibition. Broad anti-tumor activity suggests SCR-8079 central role in breast cancer treatment.

Citation Format: Feng Zhou, Guimei Yang, Feng Tang, Yan Zhang, Wenqing Yang, Liting Xue, Ping Chen, Renhong Tang. Discovery of SCR-8079, a novel and selective CDK2/4/6 inhibitor overcomes the resistance to CDK4/6 inhibition and demonstrates broad anti-tumor activities in breast cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5642.
Abstract 5644: Activation of p53 in prolonged prometaphase
Authors: Anderson Megan , Levesque Aime A.
Published: June 2022

The tumor suppressor p53 plays a critical role in protecting cells from aberrant divisions in the face of DNA damage, and while its role in DNA damage checkpoints have been extensively studied, its role in the mitotic checkpoint is less well characterized. The mitotic checkpoint prevents completion of mitosis until chromosomes have made bipolar kinetochore attachments to microtubules. Previous studies have shown that cells that experience a prolonged prometaphase(>1.5 h) following treatment with microtubule destabilizing drugs will arrest in G1 following eventual exit from mitosis. Given its role in DNA damage checkpoints, p53 appears to be a likely candidate for involvement in this arrest. The goal of the current study is to investigate the role of p53 in this G1 arrest following prolonged prometaphase. Three cells lines were utilized:MCF10A, MCF10A/αp53 which overexpressed shRNA to p53, and MCF10A/OD which overexpresses the p53 oligomerization domain. Cells were treated with 9 μM RO-3306 for 18 h to synchronize cells at the G2/M transition. The RO-3306 was then removed and cells were treated with a microtubule destabilizing drug, nocodazole, at a concentration of 0.08 μM for 1.5 or 2.5 h to cause prometaphase arrest. The cells were then washed to remove nocodazole, and the cells were harvested at various time points and analyzed via flow cytometry and Western blot. Flow cytometry analysis in in all three cell lines showed an accumulation of cells in G1 at 12 hours in for both treatment times (1.5 and 2.5 h), with subsequent increases in sub-G1 populations by 24 hours. Western blot analysis revealed activation of p53 by phosphorylation of ser20 and activation of p21 in the MCF10A and MCF10A/OD, but not in the MCF10A/αp53 for both treatment times. Taken together, these results suggest that activation of p53 alone is not sufficient to elicit the G1 arrest, as the MCF10A/αp53 cells arrested in G1 despite the absence of p53 protein.

Citation Format: Megan Anderson, Aime A. Levesque. Activation of p53 in prolonged prometaphase [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5644.
Abstract 5647: PTEN loss is associated with elevation of cell cycle signature in human glioblastoma transcriptome
Authors: Liu Tian , Or Penelope Mei-Yu , Wong Chi-Wai , Cheung Stanley Kwok-Kuen , Wang Yubing , Wang Yiwei , Ho Wayne Lut-Heng , Chan Andrew M.
Published: June 2022

Glioblastoma is the most lethal type of brain cancer with universally poor prognosis. Despite advanced treatment, the cancer recurs frequently. Phosphatase and tensin homolog (PTEN) is a tumor suppressor gene whose mutations have been found to be one of the most frequent events in GBM. PTEN acts as a negative regulator of the phosphoinositide 3-kinase (PI3K) pathway. GBM transcriptome data from The Cancer Genome Atlas (TCGA) revealed a positive enrichment of cell cycle and PI3K pathway. Moreover, weighted gene co-expression network analysis (WGCNA) on TCGA GBMLGG cohort revealed a cell cycle-related module (‘cell-cycle’ module), which was shown to be positively correlated with PTEN mutation status. This ‘cell-cycle’ module also showed a positive correlation with glioma aggressiveness.We then utilized a nestin-cre;Pten-fl/fl mouse model to investigate the consequences of PTEN loss that may be involved in GBM. Based on our preliminary data, transcriptomic profiling of primary astrocytes derived from Pten knockout mice revealed an overlapping enrichment of cell cycle related pathways with human GBM. Four cell cycle genes, RCC1, RCC2, NEK2, and CHK2, were validated to be significantly upregulated in Pten-null astrocytes by qRT-PCR. Regulator of chromatin condensation 1 (RCC1) and Regulator of chromatin condensation 2 (RCC2) both belong to the RCC1 family. Accumulating evidence demonstrated that both RCC1 and RCC2 are involved in tumorigenesis of multiple cancers and cell cycle progression. By siRNA inhibition, we demonstrated that silencing of either RCC1 or RCC2 in glioblastoma cell lines suppresses GBM cell growth. Moreover, we found that RCC2 is essential for both G1-S and G2-M transition. Additionally, RCC2 silencing and a PI3K inhibitor LY294002 inhibit glioblastoma cell viability in a synergistic manner. In summary, PTEN deficiency leads to the alteration of cell cycle progression, which may promote tumorigenesis of glioblastoma. RCC1 and RCC2 have been demonstrated to be potential targets regulated by PTEN and affects cell viability. RCC2 was shown to be a key regulator of cell cycle progression. To further explore the RCC1 and RCC2 roles, we will find the potential downstream target of RCC1 and RCC2 and its potential therapeutic effect in vivo. Funding: This work is supported by a General Research Fund grant (#14113519) from the University Grants Committee of Hong Kong.

Citation Format: Tian Liu, Penelope Mei-Yu Or, Chi-Wai Wong, Stanley Kwok-Kuen Cheung, Yubing Wang, Yiwei Wang, Wayne Lut-Heng Ho, Andrew M. Chan. PTEN loss is associated with elevation of cell cycle signature in human glioblastoma transcriptome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5647.
Abstract 5651: Characterization the mechanistic role of the proapoptotic receptor XEDAR and its therapeutic potential in TNBC
Authors: Lin Chih-Yi , Yu Chung-Jen , Wang Chih-Yang , Liu Kai-Jun , Lai Jiun-I
Published: June 2022

Breast cancer is one of the most common cancers and a leading cause of death in women worldwide. Among these subtypes, triple negative breast cancer (TNBC) has the worst prognosis, with a dismal outcome especially in metastatic disease. Metastatic TNBC treated with conventional chemotherapy has a median overall survival (OS) of ~ 18 months. The addition of checkpoint inhibitors extend the median OS to more than 2 years in PD-L1 positive patients, but ultimately most patients succumb to the disease. Currently TNBC still poses as a clinical unmet need, and further understanding of the cancer biology may shed light in improving therapeutics against this deadly disease. Apoptosis, or programmed cell death, is a crucial function for cell homeostasis. The ability to evade or circumvent apoptosis is an important hallmark of cancer cells. X-linked ectodermal dysplasia receptor (XEDAR), a cell membrane receptor that binds to the pro-apoptotic ligand EDA-A2, is a member of the TNF receptor family and has been reported to be downregulated in breast cancer cells. XEDAR has been shown to induce downstream apoptosis by binding to EDA-A2, by a mechanism similar to extrinsic apoptotic pathway. By interrogating clinical databases and cross comparison using TCGA, CCLE, and other breast cancer datasets, we discover XEDAR as substantially downregulated in TNBC. Transcription profile analysis between different XEDAR expressing profiles uncovered novel pathways that could be potentially targeted for TNBC treatment. RNA-seq profiling in XEDAR overexpressing TNBC cells were cross compared with aforementioned discovered pathways. Vulnerable pathways including angiogenesis were discovered as possible therapeutic targets. As a proof of concept, we combined angiogenesis inhibitors with EDA-A2 ligand treatment in XEDAR overexpression TNBC cells and observed synergistic effects for combination. Our study uncover XEDAR as a potential target for further treatment in TNBC, which remains to be further validated in preclinical and clinical studies.

Citation Format: Chih-Yi Lin, Chung-Jen Yu, Chih-Yang Wang, Kai-Jun Liu, Jiun-I Lai. Characterization the mechanistic role of the proapoptotic receptor XEDAR and its therapeutic potential in TNBC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5651.
Abstract 5655: Brefeldin A mediates integrated stress response and in combination with Navitoclax induces apoptosis in prostate cancer cells
Authors: Ohtsu Akira , Arai Seiji , Sawada Tatsuhiro , Miyazawa Yoshiyuki , Sekine Yoshitaka , Suzuki Kazuhiro
Published: June 2022

Introduction and Objectives: Metastatic castration resistance prostate cancer is a lethal disease. New AR-axis-targeted agent are available, but they will eventually become ineffective. Brefeldin A, an endoplasmic reticulum (ER) protein transport inhibitor, has been shown to cause ER stress. Navitoclax is a BH3 mimetic drug that targets anti-apoptotic proteins (BCL2 and BCLXL) and induces apoptosis in some solid tumors. Here, we investigated the efficacy of Brefeldin A combined with navitoclax on prostate cancer cells.

Materials and Methods: We assessed the effect of combination therapy for prostate cancer cells using MTS assay, qRT-PCR, luciferase assay, and western blot.

Results: Combination therapy with Brefeldin A and navitoclax synergistically decreased cell viability in prostate cancer cells. Mechanistically, Brefeldin A induced MCL1 degradation and, combined with navitoclax, drove apoptosis. Further, integrated stress response was at least in part involved in Brefeldin A-induced MCL1 degradation.

Conclusions: Combination therapy with Brefeldin A and navitoclax shows synergistic anti-tumor effects in prostate cancer cells. These results suggest that Brefeldin A might still be effective in prostate cancer if used with navitoclax.

Citation Format: Akira Ohtsu, Seiji Arai, Tatsuhiro Sawada, Yoshiyuki Miyazawa, Yoshitaka Sekine, Kazuhiro Suzuki. Brefeldin A mediates integrated stress response and in combination with Navitoclax induces apoptosis in prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5655.
Abstract 5670: TRPM8 ion channel role in prostate cancer: Actions as a rapid testosterone signaling receptor
Authors: Velpula Kiran , Shishido Katherine , Bayen Susovon , Asuthkar Swapna
Published: June 2022

The transient receptor potential melastatin 8 (TRPM8) is well-known for its role in cold sensation in somatosensory neurons. TRPM8 was first identified as a prostate epithelial cell-specific gene, however, its role was unclear due to the absence of its endogenous agonist. We are the first to discover the novel role of TRPM8 as a rapid testosterone receptor. The TRPM8 mRNA is highly expressed in prostate cancer (PC) and is lost during the transition to androgen-independent prostate cancer (AIPC). Although emerging studies have shed light regarding androgen regulation of TRPM8 mRNA expression, we found that the addition of androgen receptor (AR) on the lipid bilayers inhibited testosterone-TRPM8 induced Ca2+ uptake. Additionally, our IHC revealed increased internalization of the TRPM8 protein in high-grade PC and that TRPM8 protein was targeted for proteasomal degradation in PC. We observed that inhibition of AR and UBA1 promoted the stabilization of TRPM8 on the plasma membrane, triggering Ca2+-induced cytotoxicity and apoptosis in both androgen dependent and androgen independent PC cells. Furthermore, in line with previous studies, we showed that testosterone-induced TRPM8 activation on the planar lipid bilayers also required phosphatidylinositol 4,5-bisphosphate (PIP2). Loss of PTEN is associated with tumor recurrence and the transition to AIPC. Thus, PTEN loss mediated PIP2 deficiency may be an important mechanism of TRPM8 desensitization in PC. Therefore, we propose that the rescue of TRPM8 activity on the plasma membrane combined with AR targeting may be an effective therapy for PC.

Citation Format: Kiran Velpula, Katherine Shishido, Susovon Bayen, Swapna Asuthkar. TRPM8 ion channel role in prostate cancer: Actions as a rapid testosterone signaling receptor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5670.
Abstract 5677: βTrCP1 is a substrate of extracellular signal-regulated kinase 2
Authors: Lee Ga-Eun , Lee Cheol-Jung , An Hyun-Jung , Chen Weidong , Jeung Dohyun , Choi Youngwon , Cho Yong-Yeon
Published: June 2022

ERK1 and ERK2, downstream kinases of MEKs, transduce activation signals to a large number of cytosolic and nuclear substrates specifically involved in cellular signaling of transcription factors responsible for particular cellular processes. Thus, dysregulation of the cascade frequently leads to the development of diverse diseases, including > 90% of all cancers. However, although signaling mechanisms of ERKs by phosphorylation have well-known, long-term protein amount regulation has not clearly elucidated. In this study, we proved that βTrCP1 is a novel binding protein of ERK2. The interaction between ERK2 and βTrCP1 was occurred via F-box and linker domains spanning aa 192-265. Amino acid alignment of βTrCP1 showed that there are two independent putative sites for ERK docking. The mutations of the putative docking sites from lysine to alanine abrogated the interaction between ERK2 and βTrCP1. Importantly, ERK activation induced by epidermal growth factor induces βTrCP1 phosphorylation, resulting in facilitation of βTrCP1 half-life. Although the phosphorylation sites of βTrCP1 by ERK2 has not been identified, βTrCP1 tumor suppressive activity may be regulated via ERK2 when the cells are stimulated by tumor promoters such as EGF.

Citation Format: Ga-Eun Lee, Cheol-Jung Lee, Hyun-Jung An, Weidong Chen, Dohyun Jeung, Youngwon Choi, Yong-Yeon Cho. βTrCP1 is a substrate of extracellular signal-regulated kinase 2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5677.
Abstract 5681: Metabolic targeting of NRF2 potentiates the efficacy of TRAP1 inhibitor GTPP in colorectal cancer
Authors: Tsai Hong-Yuan , Chen Ru , Shroyer Noah , Pan Sheng
Published: June 2022

Tumor necrosis factor receptor-associated protein 1 (TRAP1) is a mitochondrial homolog of HSP90 chaperones. It plays an important role in protection against oxidative stress and apoptosis by regulating reactive oxidative species (ROS) and may also exert the cytoprotective activities by regulating mitochondrial permeability transition pore opening. Recent studies have suggested that TRAP1 may regulate metabolism and mitochondrial homeostasis in cancer. To further elucidate the mechanistic role of TRAP1 in regulating tumor cell survival, we used cellular models to investigate cellular effects and signaling pathways regulated by TRAP1 in several colon cancer cell lines. Inhibition of TRAP1 by a small molecule inhibitor, Gamitrinib-triphenylphosphonium (GTPP), in colon cancer cells led to ROS production, ER stress, reduction of cell viability and induction of cell death. Interestingly, we observed wide-range of responses to TRAP1 inhibition among these colon cancer cell lines. In GTPP sensitive cell lines (SW48), GTPP induced upregulation of GRP78, CHOP and cleavage form PARP proteins. In contract, in GTPP resistant cells (DLD1 and RKO), GTPP treatment highly induced activation of antioxidant gene NRF2, leading to better cell survival under oxidative environment. NRF2 target genes HO1 and NQO1 were upregulated in GTPP-treated DLD1 cells, making these cells more resistant to GTPP treatment. Using reporter assay, we further found that transcriptional activation of antioxidative responds element (ARE) was increased in GTPP-treated DLD1 and RKO cells (GTPP resistant), but not in SW48 cells (GTPP sensitive). Combination of NRF2 inhibitor ML385 and GTPP led to excessive ROS production and exacerbated GTPP-induced cell death in GTPP resistant cells. These new findings for the first-time link TRAP1 and NRF2 in a common pathway regulating ROS production in colon cancer. Taken together, dual targeting of TRAP1 and NRF2 may potentially overcome the tumor cell resistance through disruption of mitochondrial redox homeostasis.

Citation Format: Hong-Yuan Tsai, Ru Chen, Noah Shroyer, Sheng Pan. Metabolic targeting of NRF2 potentiates the efficacy of TRAP1 inhibitor GTPP in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5681.
Abstract 5682: Accelerated biological age is a driver of cancer susceptibility in genetic high risk breast tissue
Authors: Miyano Masaru , Shalabi Sundus , Sayaman Rosalyn W. , Stampfer Martha , Seewaldt Victoria E. , LaBarge Mark A.
Published: June 2022

During aging in the human mammary gland, luminal epithelial cells lose lineage fidelity by expressing markers normally expressed in myoepithelial cells. We hypothesize that loss of lineage fidelity is a general manifestation of epithelia that are susceptible to cancer initiation. We show that histologically normal breast tissue from younger women who are susceptible to breast cancer because they harbor a germline mutation in BRCA1, BRCA2, or PALB2 genes, exhibit hallmarks of accelerated aging. These include proportionately increased luminal epithelial cells that acquired myoepithelial markers, decreased proportions of myoepithelial cells, and a basal differentiation bias or failure of differentiation of cKit+ progenitors. High-risk luminal and myoepithelial cells are transcriptionally enriched for genes of the opposite lineage, inflammatory, and cancer-related pathways. Genetically high risk luminal epithelial cells also show evidence of accelerated age, by as much as four decades compared to their chronological age, using a breast specific biological clock comprised of measurements of methylation and expression of the luminal-specific ELF5 transcription factor. We have identified breast aging hallmarks that reflect a convergent biology of cancer susceptibility, regardless of the specific underlying genetic or age-dependent risk, or the associated breast cancer subtype.

Citation Format: Masaru Miyano, Sundus Shalabi, Rosalyn W. Sayaman, Martha Stampfer, Victoria E. Seewaldt, Mark A. LaBarge. Accelerated biological age is a driver of cancer susceptibility in genetic high risk breast tissue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5682.