bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 340: The Hu2G10 tumor-selective anti-Trop-2 monoclonal antibody targets the cleaved-activated Trop-2 and shows therapeutic efficacy against multiple human cancers
Authors: Alberti Saverio , Trerotola Marco , Guerra Emanuela
Published: June 2022

Trop-2 is a transmembrane glycoprotein that transduces a calcium signal and activates growth-signaling networks that converge on Akt, ERK, Cyclin D1, NFkB (1). We discovered that Trop-2 cleavage by ADAM10 is an activator switch for induction of cancer growth and metastatic diffusion (2). This cleavage causes a spatial rearrangement of the extracellular portion of Trop-2 and exposes protein sites that would normally be inaccessible.We devised a strategy to obtain monoclonal antibodies (mAbs) capable of recognizing these cancer-exposed sites.Most Trop-2-targeted approaches are based on anti-Trop-2 mAbs that recognize a single immunodominant epitope poised between the globular and stem regions. Such mAbs have limited therapeutic index.We removed the immunodominant epitope by deletion mutagenesis. To optimize breadth of immune response, mice were immunized with target proteins produced in cells with different end-glycosylation patterns, including tumor cells, insect, yeast, bacterial cells. Screening for cancer-specific mAbs were performed by cell-based ELISA assays, ELISA assays on recombinant target proteins, bio-layer interferometry, flow cytometry and fluorescence microscopy on cleaved, wild-type and glycosylation-site mutagenized Trop-2. mAbs were obtained that efficiently bound Trop-2 expressing cancer cells and were able to inhibit cell growth in vitro. We humanized the 2G10 mAb as the IgG1 Hu2G10 antibody with an affinity for recombinant, cancer-specific, cleaved Trop-2 that is several orders of magnitude higher than for the wtTrop-2. In vivo the naked Hu2G10 antibody was effective at inhibiting the growth of breast, colon, ovary and prostate cancers. In the ADC setting Hu2G10 drove high anticancer effectiveness with unprecedented specificity, for best-in-class anticancer therapy. (1) E. Guerra et al., The Trop-2 signalling network in cancer growth. Oncogene 32, 1594-1600 (2013).(2) M. Trerotola et al., Trop-2 cleavage by ADAM10 is an activator switch for cancer growth and metastasis. Neoplasia 23, 415-428 (2021).

Citation Format: Saverio Alberti, Marco Trerotola, Emanuela Guerra. The Hu2G10 tumor-selective anti-Trop-2 monoclonal antibody targets the cleaved-activated Trop-2 and shows therapeutic efficacy against multiple human 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 340.
Abstract 3444: Administration of anti-CD40 enhances local and systemic antitumor efficacy of radiotherapy in allograft tumor model of a check-point blockade resistant melanoma
Authors: Pandey Sanjay , Chavez Claudia G. , Basu Indranil , Minn Andy , Guha Chandan
Published: June 2022

Resistance to immune checkpoint therapy develops in a subset of patients after initial response. Therefore, we hypothesized that defective antigen presentation contributes to immune resistance, and a sequential therapy comprising of ablative radiation therapy (RT) and agonist αCD40 antibody can reprogram the tumor-infiltrating myeloid and dendritic cells for effective in-situ tumor antigen presentation and activation of T cells. Palpable B16-F10-Res499 tumors in C57BL/6 mice, resistant to the systemic effects of RT and αCTLA-4 blockade, were treated with 3 fractions of 20Gy (RT) followed by agonist αCD40 antibody (3x100μg). Tumor growth, survival, and anti-tumoral immune memory after rechallenge was monitored. Mice were sacrificed on Day 16 post-RT, and immune cells from irradiated tumors and draining lymph nodes (DLN) were analyzed using flow cytometry. There was complete tumor regression and enhanced anti-tumoral immune memory in RT+αCD40-treated animals. In a dual tumor model, combination therapy significantly delayed abscopal tumor growth by 64% on D30 (p<0.0001). When compared to unirradiated or tumors treated with RT alone, there was a significant increase in cell surface expression of co-stimulatory molecules (CD80, CD86, CD40 and 4-1BBL) and TNF-α, and iNOS in the CD103+ DCs and myeloid cells (p<0.05) indicating a reprogramming of antigen presentation and co-stimulatory function in MDSCs. There was an increase in CD8+ T cells with reduced CD4/CD8 ratio (p<0.01) in abscopal tumors and DLN in the RT+αCD40 group. Combination treatment enhanced the frequency of proliferating Ki67+ (p<0.001) and IFNγ+ (p<0.01) CD8 T cells and an increase in the Ki67+ high GRZ+ (granzyme secreting) population in the pool of early exhausted cells (PD1intEOMESlow). Interestingly CD8 depletion by anti-CD8 only partially reversed the effect of the combination group. Furthermore, αCD40 showed an increase in the CD11b+Ly6C population in the tumors. Also, Ly6C depletion completely reversed the effect of the IR+anti-CD40 treatment.

Conclusion: Combination of ablative RT, followed by αCD40 therapy, overcame immune resistance in murine melanoma by enhancing systemic anti-tumoral immunity, abscopal effects, survival, and anti-tumoral immune memory. The immunomodulatory effects of αCD40 are dependent upon Ly6C+ cells and partially on CD8+ T cells.

Citation Format: Sanjay Pandey, Claudia G. Chavez, Indranil Basu, Andy Minn, Chandan Guha. Administration of anti-CD40 enhances local and systemic antitumor efficacy of radiotherapy in allograft tumor model of a check-point blockade resistant melanoma [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 3444.
Abstract 3465: Efficacy of concomitant application of Tumor Treating Fields (TTFields), temozolomide and lomustine in glioblastoma cancer cells in vitro
Authors: Fishman Hila , Monin Roni , Dor-On Eyal , Haber Adi , Giladi Moshe , Weinberg Uri , Palti Yoram
Published: June 2022

Background: Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Newly diagnosed GBM (ndGBM) is treated with adjuvant temozolomide (TMZ), however, more than 50% of patients do not respond to therapy. Tumor Treating Fields (TTFields) therapy concomitant with maintenance TMZ was approved by the FDA in 2015 and represents a major advance in treatment of patients with ndGBM. Recently, lomustine (CCNU) together with TMZ demonstrated improved overall and progression-free survival following resection and radiochemotherapy in patients with ndGBM. Accordingly, the current study aimed to examine the effect of concomitant application of TTFields with TMZ and CCNU in GBM cells.

Methods: GBM cells (U-87 MG and LN229) were treated for 72 h with TTFields at a frequency of 200 kHz and an intensity of 1 V/cm RMS using the inovitro system. Efficacy of combining TTFields with TMZ and/or CCNU was tested by measuring cell survival, clonogenic potential, overall effect (multiplicity product of cytotoxicity and clonogenicity), and apoptosis induction.

Results: Combination of TMZ and TTFields resulted in increased cytotoxicity compared with each treatment alone. The cytotoxic effect resulting from co-application of CCNU with TTFields suggested a synergistic interaction between the two modalities. The clonogenic, overall, and apoptotic effects of TMZ and CCNU were also enhanced following co-treatment with TTFields. The triple combination of TTFields with both TMZ and CCNU was more efficacious than TMZ/CCNU or TTFields separately.

Conclusions: The current research suggests potential benefits for the treatment of GBM using concomitant application of TTFields with TMZ/CCNU.

Citation Format: Hila Fishman, Roni Monin, Eyal Dor-On, Adi Haber, Moshe Giladi, Uri Weinberg, Yoram Palti. Efficacy of concomitant application of Tumor Treating Fields (TTFields), temozolomide and lomustine in glioblastoma cancer cells in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3465.
Abstract 3494: Characterizing the relationship between genotype and phenotype in DNA damage response-altered pancreatic cancer models
Authors: Carroll James R. , Link Jason M. , Brody Jonathan R.
Published: June 2022

Alterations in DNA damage response (DDR) proteins are prevalent across cancers and present unique opportunities for the therapeutic induction of synthetic lethality (i.e., two gene deficiencies in the same pathway synergize to kill tumor cells). In pancreatic adenocarcinoma, patients harboring alterations in DDR genes, such as in homology-directed repair (HDR), comprise the 10-20% of patients that may benefit from the recent FDA approval of Olaparib, a poly (ADP-ribose) polymerase inhibitor that disrupts non-homologous end joining (NHEJ). Despite being the best-in-class targeted therapy for DDR-altered pancreatic cancers, a subset of patients fails to respond to Olaparib and those that initially respond eventually go on to develop resistance. The mechanisms underlying resistance are poorly elucidated but suggest that some patients harboring DDR-altered tumors are HDR-proficient or revert to HDR-proficiency during therapy, bypassing the second gene deficiency requisite for synthetic lethal induction with targeted therapy (e.g., Olaparib). Utilizing patient-derived models of cancer, we are actively investigating DDR-altered, pancreatic tumor cell lines and exploring the relationship between DDR-alterations and HDR-deficiency with three goals: [1] To evaluate the prevalence of HDR-proficiency in BRCA-altered tumors, [2] to understand the extent to which patient-derived models of cancer are concordant and predictive of clinical outcomes, and [3] to identify novel therapeutic strategies for resistant patients. So far, we have observed HDR-proficiency by functional assays (e.g., RAD51 foci formation) in DDR-altered patient-derived cell lines that corresponds with poor response to Olaparib in vitro, and resistance to platinum therapy clinically. Whereas DDR-altered HDR-deficient lines had greater sensitivity to Olaparib and platinum therapy. These early data suggest that measures of HDR by functional assay may be more predictive of clinical therapeutic responses than the use of genetic signatures alone.

Citation Format: James R. Carroll, Jason M. Link, Jonathan R. Brody. Characterizing the relationship between genotype and phenotype in DNA damage response-altered pancreatic cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3494.
Abstract 3512: Immunotherapy by STING activation in a CRISPR induce mouse model of GBM decrease tumor progression by CD8 T-cells and altered vascularity
Authors: Joseph Justin V. , Cai Huiqiang , Hansen Brian , Paludan Soren R. , Vendelbo Mikkel , Thomsen Martin K.
Published: June 2022

Intrinsic malignant brain tumors, such as glioblastoma (GBM) are frequently resistant to immunotherapy with few hyper-mutated glioblastomas showing response. Here we have applied a long-term treatment with STING agonist and PD-1 inhibitors alone and in combination towards eliciting enhanced host immune response to combat GBM progression. To address these questions we generated mouse models of GBM by intracranial implantation of a murine GBM stem cell line or orthotopic CRISPR induced mutation to astrocytes. Systemic administration of STING agonist crosses the blood-brain barrier and induces a type-1 IFN signature in the brain and this was further enhanced in the tumor milieu. Treatment outcomes were addressed by MRi and treated animals showed a significant reduction in tumor volume and hence improved survival in comparison to the animals in the control group. Histochemical evaluation of tumor samples from the animals that received treatment showed elevated necrosis and aberrant/leaky vasculature in comparison to the control tumor samples. The presence of cytotoxic T-cells were similar between the groups but activated PD-1 positive T-cells were increased in treated tumors. Ex-vivo analysis of isolated T-cells from tumor baring mice confirms cytotoxic T-cells targeting the GBM cells. In conclusion, application of STING agonist promotes alteration of vasculitis and priming of T-cells in GBM results in increased survival and decreased tumor progression. These results reveal that GBM can be targeted by immune therapy through systemic activation of STING/IFN pathway.

Citation Format: Justin V. Joseph, Huiqiang Cai, Brian Hansen, Soren R. Paludan, Mikkel Vendelbo, Martin K. Thomsen. Immunotherapy by STING activation in a CRISPR induce mouse model of GBM decrease tumor progression by CD8 T-cells and altered vascularity [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 3512.
Abstract 3546: DFMO based improvement in survival of pancreatic cancer-bearing mice is associated with modulation of immune suppression in the tumor microenvironment
Authors: Nakkina Sai Preethi , Gitto Sarah B. , Beardsley Jordan M. , Pandey Veethika , Rohr Michael M. , Parikh Jignesh , Phanstiel Otto , Altomare Deborah A.
Published: June 2022

Existing therapeutics have failed to improve pancreatic ductal adenocarcinoma (PDAC) patient outcomes, in part due to tumor associated immune suppression and upregulation of compensatory mechanisms. KRAS and c-MYC are important oncogenes in PDAC linked to tumor immune suppression. We describe the use of difluoromethylornithine (DFMO) and a c-RAF inhibitor (GW5074) to indirectly target c-MYC and KRAS, respectively. DFMO in combination with GW5074 was tested for ability to improve pancreatic cancer outcomes. Pancreatic cancer cells showed decreased cell viability and increased apoptosis in response to a combination of DFMO + GW5074. In vivo orthotopic models of pancreatic tumors had decreased tumor weight in DFMO + GW5074 treated mice, when compared to control group. However, only treatment with single agent DFMO resulted in improved survival of immunocompetent pancreatic tumor bearing mice with respect to control, in contrast to treatment with GW5074 alone or DFMO + GW5074. To understand why the in vivo data was contrary to in vitro results, immunohistochemical analysis of immune cells in the tumor microenvironment was used to reveal increased expression of markers associated with anti-tumor effects such as CD86, CD3, CD4 and CD8 in DFMO treated tumors. Tumors treated with DFMO also displayed decreased expression of MYC, suggesting that DFMO-associated MYC suppression could be linked to decreased immune suppression in the tumor microenvironment and improved survival. In contrast, GW5074 treatment maintained MYC expression in tumors. Overall, the present study points to DFMO being an immunomodulatory agent, and a need for further understanding of DFMO-based therapeutic strategies in PDAC.

Citation Format: Sai Preethi Nakkina, Sarah B. Gitto, Jordan M. Beardsley, Veethika Pandey, Michael M. Rohr, Jignesh Parikh, Otto Phanstiel, Deborah A. Altomare. DFMO based improvement in survival of pancreatic cancer-bearing mice is associated with modulation of immune suppression in the 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 3546.
Abstract 3547: IL-12-based cytokine factories modulate tumor microenvironment to eradicate pancreatic tumors in mice and are well tolerated in non-human primates
Authors: Nash Amanda , Aghlara-Fotovat Samira , Castillo Bertha , Nguyen Annie , Cui Andrew , Hernandez Andrea , Rios Peter , Ghani Sofia , Joshi Ira , Xu Chunyu , Sheth Rahul , Peng Weiyi , Oberholzer Jose , Jazaeri Amir , Veiseh Omid
Published: June 2022

Pancreatic cancer is often diagnosed at advanced stages and responds poorly to chemotherapy. Because high tumor T cell infiltration corresponds with better clinical outcomes in pancreatic cancer patients, immunotherapy has gained significant interest over the last decade for the treatment of recurrent pancreatic cancer. IL-12 is a proinflammatory cytokine with pleiotropic effects including activation of CD8+ T cells and NK cells. Unfortunately, systemic high dose IL-12 administration led to severe toxicities in clinical trials which has limited further development of this cytokine as a cancer therapeutic. To address this limitation, we developed an implantable cytokine delivery platform to allow for local administration of IL-12. These cytokine factories, composed of genetically engineered epithelial cells encapsulated in biocompatible polymers, allow for safe and controlled dosing in vivo. Tumor adjacent administration of IL-12-based cytokine factories caused reduction of intraperitoneal pan02 tumor burden by 80% after only 1 week of treatment in mice with pancreatic cancer. Single cell RNAseq of the tumor adjacent immune cells at this time point showed 2x more T and NK cells present in the IL-12 treated mice than untreated mice suggesting modulation of the tumor microenvironment via immune cell infiltration. Importantly, the necessary IL-12 dose was well tolerated in all mice without signs of toxicity for 180 days. In efforts to evaluate the translatability of this platform, we further tested IL-12-based cytokine factories in a non-human primate. The cytokine factories produced a high local IL-12 concentration without substantial leakage into the systemic circulation and were well tolerated by the primates as shown by the lack of fever or weight loss, as well as the lack of renal or liver toxicity. Our findings highlight the therapeutic potential of IL-12 treatments when administered locally via cytokine factories in preclinical animal models. Further, these findings provide rationale for future development and clinical testing of cytokine factories for treatment of a wide range of metastatic peritoneal cancers in humans.

Citation Format: Amanda Nash, Samira Aghlara-Fotovat, Bertha Castillo, Annie Nguyen, Andrew Cui, Andrea Hernandez, Peter Rios, Sofia Ghani, Ira Joshi, Chunyu Xu, Rahul Sheth, Weiyi Peng, Jose Oberholzer, Amir Jazaeri, Omid Veiseh. IL-12-based cytokine factories modulate tumor microenvironment to eradicate pancreatic tumors in mice and are well tolerated in non-human primates [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 3547.
Abstract 3548: Role of the cancer cell proteome and tumor microenvironment in the hyperprogression (HP) phenotype response to immune checkpoint blockade
Authors: George Andrew , Sahin Ilyas , Zhang Shengliang , El-Deiry Wafik S.
Published: June 2022

Immune checkpoint blockade (ICB) immunotherapy strategies have yielded significant successes in recent years. Unfortunately, such treatments are not always successful. While tumor resistance to immunotherapy is often the reason, a subpopulation of patients treated with ICB show an acceleration in tumor growth rate, termed hyperprogressive disease (HPD) or hyperprogression (HP). Different studies have evaluated the incidence rate of HPD at 4% to 30%, though clear predictors have been elusive. An impediment to progress on investigating HPD has long been the lack of a reliable disease model. We recently reported a humanized mouse model of hyperprogression using mismatch repair deficient (MMR-d) p53-/- HCT-116 colorectal cancer cells implanted subcutaneously into athymic mice humanized with human CD8+ T-cell line TALL-104 and treated with anti-PD-1 Pembrolizumab. Flow cytometry was used to ensure the systemic establishment of the TALL-104 CD8+ human T-cells used to humanize the athymic mice and characterize immune tumor infiltration, which was not different between groups. Immunoperoxidase staining revealed increased expression of proliferation marker Ki67 within the HPD xenografts, supporting the finding that HPD tumors were exhibiting accelerated growth. Initial human cytokine analysis revealed a significant elevation in three cytokines (IFN-γ, TRAIL R2, and RANK L) and a significant decrease in four (CCL2, Chitinase 3-like 1, IL-4, and TNF-α). We attempted to mitigate HP through administration of anti-EGFR Panitumumab based on some clinical studies linking EGFR aberration to HPD but found worsened HPD in cotreated mice. We are conducting RNA sequencing to identify any changes in the RNAome of the HPD model, and immunoperoxidase analysis of resected tumor tissue for cytokine expression and cell death markers that may provide clues for accelerated growth within the HPD tumor microenvironment. Future studies will also focus on the interplay between Pembrolizumab and Panitumumab observed preliminarily to exacerbate the HPD with more comprehensive in vivo studies including of patient-derived xenotransplants.

Citation Format: Andrew George, Ilyas Sahin, Shengliang Zhang, Wafik S. El-Deiry. Role of the cancer cell proteome and tumor microenvironment in the hyperprogression (HP) phenotype response to immune checkpoint blockade [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 3548.
Abstract 3568: Robust and potent dendritic cells for cancer immunotherapy
Authors: Azeem Waqas , Lellahi Seyed Mohammad , Hua Yaping , Øyan Anne Margrete , Gabriel Benjamin , Kalland Karl-Henning
Published: June 2022

Background: Dendritic cells (DCs) are fundamental to adaptive immunity by detecting, engulfing and presenting foreign or changed antigenic peptides to lymphocytes that thereafter initiate antigen-specific immune attacks. DC-based immunotherapy against cancer has been promising for a long time, but has not yet met expectations. Cancer cell heterogeneity and numerous immune evasion mechanisms represent challenges. According to textbook renderings, DCs may induce either tolerance or immune activation depending upon the nature of the encountered antigen and the status of the microenvironment. Recently, we have discovered a more complicated scenario according to which monocyte-derived DCs (moDCs) exhibit dual pro- and anti-inflammatory features, suggesting that selected conditions that enhance pro-inflammatory features and counteract tolerogenic features could generate more robust and potent DCs for cancer therapy.

Materials and Methods: Healthy blood donor buffy coats were used for the isolation of monocytes and conventional CD141+ and CD1c+ natural circulating DCs. IL-4 and GM-CSF were used to differentiate monocytes into immature moDCs. Toll-like receptor agonists were used to induce DC maturation, and specific agonists and inhibitors were tested in different DC variants. Flow cytometry, ELISA determination of cytokine secretion, HPLC-based quantitation of kynurenine secretion, genome-wide gene expression analyses and functional assays, such as antigen uptake, migration and the mixed leukocyte reaction were used for evaluation of treated DCs.

Results: Conventional DCs were more susceptible to apoptosis, and dependent upon culture conditions, than moDCs. Inhibition of β-catenin signaling stimulated several pro-inflammatory features, e.g. increased IL-12 and decreased IL-10 secretion, with reciprocal effects caused by β-catenin stimulation. Maturation of moDCs was accompanied by very strong induction of indoleamine 2, 3-dioxygenase 1 (IDO1) transcription and paralleled by increased kynurenine secretion, but this was partially counteracted by β-catenin stimulation.

Conclusions: Preparation of more potent DCs for cancer therapy needs to take into account DC longevity and conflicting activation patterns of pro- and anti-inflammatory abilities.

Citation Format: Waqas Azeem, Seyed Mohammad Lellahi, Yaping Hua, Anne Margrete Øyan, Benjamin Gabriel, Karl-Henning Kalland. Robust and potent dendritic cells for cancer 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 3568.
Abstract 3570: Prospects for personalized cancer vaccines: The oncolytic and immunotherapeutic HSV-1(VC2) virus expressing an ovalbumin (OVA) antigen elicits robust anti-OVA immune responses
Authors: Uche Ifeanyi K. , Stanfield Brent , Rudd Jared , Kousoulas Konstantin , Rider Paul J.
Published: June 2022

Cancers result from unique cellular transformation events resulting in the expression of cancer antigens that vary widely among different types of cancers. Ideally, a personalized cancer treatment approach needs to target specific cancer antigen. Efforts to induce specific immune responses against tumor associated antigens (TAAs) include the expression of TAAs through viral vectors capable of expressing multiple antigens. We have previously shown that the HSV-1(VC2) vaccine vector can induce potent antitumor immune responses utilizing the B16F10-derived syngeneic melanoma mouse model. To investigate whether heterologous antigens expressed by this vaccine vector could elicit potent immune responses, we generated the recombinant virus VC2-OVA that expresses the ovalbumin antigen (OVA) fused in-frame at the amino terminus of the viral VP26 protein. Western blot analysis of infected cells in cell culture showed efficient expression of the OVA-VP26 protein. The anti-tumor efficacy of the VC2-OVA virus was tested in the B16cOVA and E.G7-OVA mouse models that constitutively express the OVA antigen to test whether this vaccine can either prevent the formation of new tumors (prophylactic modality) or reduce tumor metastasis (therapeutic modality). In addition, we evaluated the differences between intradermal, subcutaneous, and intramuscular routes of vaccination with VC2-OVA. Treatment with VC2-OVA resulted in significant reduction of tumor formation and metastasis in both the prophylactic and therapeutic modalities. Importantly, the anti-tumor efficacy was dependent on the specific mouse tumor model. Further, we found that subcutaneous and intradermal was superior to intramuscular vaccination. The VC2 virus is available as a bacterial artificial chromosome allowing for the rapid isolation of recombinant VC2-derived virus expressing multiple tumor antigens. Therefore, these results demonstrate that the VC2 vaccine virus can be used to produce personalized cancer vaccines targeting specific TAAs.

Citation Format: Ifeanyi K. Uche, Brent Stanfield, Jared Rudd, Konstantin Kousoulas, Paul J. Rider. Prospects for personalized cancer vaccines: The oncolytic and immunotherapeutic HSV-1(VC2) virus expressing an ovalbumin (OVA) antigen elicits robust anti-OVA immune responses [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 3570.
Abstract 3571: Prevention of non-small cell lung cancer with kras mutation using a novel peptide vaccine
Authors: Wang Suhe , Cao Zhengyi , Chen Jesse , Katarzyna Janczak , Baker James
Published: June 2022

Non-small cell lung cancer (NSCLC) is a significant health issue associated with morbidity and mortality. One of the important findings to emerge in NSCLC is that specific genetic mutations that lead to cancer development occur early in the disease process. Unfortunately, identifying NSCLC at its earliest stages when it is curable has been a challenge even in high risk individuals. These gene mutations, especially those involving the Kras protein, can “drive” the development of NSCLC cancer as they alter the regulation of cell growth or block programmed cell death. Mutations in Kras have been reported in 30% of lung cancer cases and are associated with worse outcomes. This neo-antigen cannot generate effective anti-tumor immunity, suggesting lack of a cellular, cytotoxic immune response to cancer cells on mucosal/epithelial surfaces. No effective therapies specifically targeting mutant Kras have been developed. To overcome poor immunogenicity of neo-antigen, newer adjuvants (NA), biocompatible nanoparticles, were used to enhance immune response. It has been reported NA can produce cytotoxic and mucosal immunity safely in humans. Producing this type of immune response to mutated Kras through immunization could produce a significant anti-tumor effect. In the current study, we first tested NA combined with mutated and wild type (MHC II) Kras peptides vaccine for immunogenicity on the same genetic background as the animals in the inducible tumor model. Our data have demonstrated that NA in combination with multiple Kras peptides can increase CD4+ and CD8+ T cell numbers in the draining lymph node cells and enhance antigen specific TH1 and TH17 responses by luminex and ELISpot to increase the ability of the vaccine to kill tumor cells and elicit long-lasting immune memory. Furthermore, we evaluated anti-tumor efficacy of this vaccine in tetracycline-inducible mouse model with Kras mutation. In this challenge model, vaccinated mice showed higher IFNɤ and IL-17 levels and decreased the tumor incidence significantly compared to PBS or peptides alone group. In conclusion, we have demonstrated the antigen-specific cellular immune responses and mononuclear cell infiltrates correlate with tumor prevention. Our data suggest that this novel vaccine could prevent the development of NSCLC after validation in an appropriate animal model.

Citation Format: Suhe Wang, Zhengyi Cao, Jesse Chen, Janczak Katarzyna, James Baker. Prevention of non-small cell lung cancer with kras mutation using a novel peptide vaccine [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 3571.
Abstract 359: Pharmacologically induced polyploidy triggers BCL2 dependence in lymphomas
Authors: Portelinha Ana , Ferreira Mariana da Silva , Erazo Tatiana , Asgari Zahra , de Stanchina Elisa , Younes Anas , Wendel Hans-Guido
Published: June 2022

Spontaneous whole genome duplication (WGD) and the adaptive mutations that disrupt cell death and proliferation checkpoints are infrequent events in aggressive B cell lymphomas. This indicates that lymphomas may be especially sensitive to therapeutics that trigger genomic instability. Here, we report the powerful therapeutic combination of Polo-like kinase 4 (PLK4) and BCL2 inhibitors for aggressive lymphomas. Mechanistically, the PLK4 inhibitor CFI-400945 impairs centrosome duplication leading to genomic instability and tetraploidy (4n) in lymphoma cells. Elimination of polyploid lymphoma cells is mediated by the pro-apoptotic BAX protein resulting in increased BCL2 dependence for cell survival. The selective BCL2 inhibitor, venetoclax, acts in a synthetic lethal manner with PLK4 inhibition in both CFI-400945 sensitive and in CFI-400945 resistant lymphomas. As PLK4 is dispensable in non-proliferating cells, synthetic lethality is preferentially observed in tumor cells, while sparing vital organs. Hence, B cell lymphomas are ill-prepared for the rapid, pharmacologic induction of polyploidy resulting in a synthetic and tumor-specific dependency on BCL2.

Citation Format: Ana Portelinha, Mariana da Silva Ferreira, Tatiana Erazo, Zahra Asgari, Elisa de Stanchina, Anas Younes, Hans-Guido Wendel. Pharmacologically induced polyploidy triggers BCL2 dependence in lymphomas [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 359.
Abstract 3611: Determining the regulation and role of mreg DC in tumor immunity
Authors: Mattiuz Raphael , Assad Nima , Hamon Pauline , Magen Assaf , Berichel Jessica Le , Merad Miriam
Published: June 2022

Therapeutic immunity against tumors is mainly determined by effector T cells. However, T cells are educated by antigen presenting cells, particularly dendritic cells (DC), that control their differentiation into effector T cells able to eliminate target tumor cells. While most studies focused on understanding T cell features leading to antitumor immunity, little is known about DC determinants required to promote effective antitumor T cell function. Yet several studies are revealing that high DC content in tumor lesions correlate with improved tumor outcome. To identify molecular program that modulate DC functionality in tissues we have profiled tumor-associated DC in mice and tumor lesions. We identified a DC molecular program that was shared between mice and human tumors that included maturation genes associated with T cell simulation and migration to the LN (Cd40, Cd80, Fscn, Ccr7), but also genes associated with immunoregulation (Socs1, Socs2, Socs3, Cd200, Pd-l1, Pd-l2, Fasl), we named mregDC (Maier et al., Nature 2020). We also found that mregDC molecular state is induced in DC1 and DC2 upon capture of tumor debris leading to hypothesize that the mregDC state identifies antigen-charged DC that migrate to lymphoid structures, including tertiary lymphoid structures and tumor draining lymph nodes to modulate tumor specific T cell immune responses. While the role of DC in the draining LN has been established the exact role played by DC in the tumor microenvironment (TME) remains unclear. To explore this question, we used multiplex imaging and spatial transcriptomics platforms to identify the distribution and spatial interactions of DC1, DC2 and mregDC within the TME of human NSCLC and HCC lesions during treatment with PD-1 blockade. We found that mregDC accumulate within the tertiary lymphoid structures together with activated T cell and B cell programs. We are continuing to generate additional data on mregDC interactions in human tumors tissues that respond or resist PD-1 blockade and should be able to provide additional information at the time of the meeting.

Citation Format: Raphael Mattiuz, Nima Assad, Pauline Hamon, Assaf Magen, Jessica Le Berichel, Miriam Merad. Determining the regulation and role of mreg DC in tumor immunity [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 3611.
Abstract 3639: Senescent stromal cells drive breast cancer tumorigenesis
Authors: Ye Jiayu (Jennifer) , Delgado Ana Paula , Powers Scott , Stewart Sheila
Published: June 2022

Age is the largest risk factor for the development of cancer, including breast cancer, which is the most frequent malignancy in women. Investigation into how age impacts breast cancer development suggests that both the accumulation of oncogenic mutations within incipient tumor cells and age-related stromal changes conspire to drive tumorigenesis. While numerous physiologic changes arise with age, we posit that the accumulation of p16INKA4 (p16) positive senescent cells, which express various cytokines, chemokines, and enzymes collectively referred to as the senescence-associated secretory phenotype (SASP) contribute to cancer progression. SASP factors not only directly promote the proliferation of tumor cells, but also create an immunosuppressive microenvironment that contributes to robust tumor growth. Immunosuppressive SASP factors are detectable in human breast cancer stroma and high p16 positivity in stromal cells strongly correlates with breast cancer recurrence regardless of subtype. To investigate the role of senescent stroma in mammary tumor development, we crossed MMTV-PyMT (PyMT) transgenic mice that spontaneously develop mammary tumors to INK-ATTAC (INK) mice, which allows selective elimination of p16-positive cells. Depletion of senescent stromal cells in PyMT/INK mice led to significantly delayed mammary tumor onset and changes in various tumor-infiltrating immune cell populations. Analyses of single-cell RNA-sequencing (scRNA-seq) datasets of murine and human mammary tumor/breast cancer samples revealed that senescence is restricted to a cancer-associated fibroblasts (CAFs) subpopulation, which expresses high levels of immune-related and extracellular matrix (ECM)-related SASP factors and shows decreasing abundance in PyMT/INK mice upon the depletion of senescent stroma. Together, these data suggest that senescent CAFs contribute to mammary gland tumorigenesis by modulating tumor immunity and remodeling ECM in the microenvironment.

Citation Format: Jiayu (Jennifer) Ye, Ana Paula Delgado, Scott Powers, Sheila Stewart. Senescent stromal cells drive breast cancer tumorigenesis [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 3639.
Abstract 3643: The role of HBP1 in controlling breast cancer dormancy reawakening
Authors: Gelman Irwin H. , Degan Seamus , Withers Henry G. , Venkata Subrahmanya Anirudh Kaligotla
Published: June 2022

At least 22% of breast cancer (BrCa) cases recur after 3 to 15 years, typically at metastatic sites such as the bone. Bone metastases derive from early disseminated tumor cells that become dormant because of interaction with specific cells that define the endosteal niche (EN) microenvironment. However, outside knowing that dormancy is driven by a p38MAPKhi, ERK1/2lo activation profile, our understanding of what factors regulate dormancy maintenance and reawakening is poor. We used a genomic shRNA screen to identify HBP1 as a suppressor of BrCa dormancy reawakening in a 3D-EN culture system. Our data indicate that under 3D-EN conditions, HBP1 is upregulated by p38MAPK, interacts with the metastasis suppressors, BRMS1 and BRMS1L, and with the histone modifiers, SIN3A and HDAC1-3. We hypothesize that HBP1 suppresses p38MAPK-mediated dormancy reawakening by complexing with BRMS1/BRMS1L/SIN3A to alter cell cycle gene expression through histone landscape remodeling. HBP1 suppresses the expression of cell cycle progression genes, such as MYC and CCND1, and concomitantly upregulates cyclin kinase inhibitors, p16 and p21. HBP1 RNA and protein levels are decreased in BrCa metastases relative to primary tumors, and this downregulation correlates with poorer overall survival. We are investigating whether the anti-histiminic drug, cyproheptadine, which upregulates HBP1 expression through the activation of p38MAPK, can suppress dormancy reawakening of BrCa cells in 3D-EN cultures and in in vivo models of bone dormancy using mouse mammary carcinoma D2A1 cell lines with varying abilities to form active or dormant metastatic bone colonization. Data will be shown addressing how cell-cell interactions and secretory factors between BrCa and bone EN cells facilitates dormancy signaling through a p38MAPK/HBP1/BRMS1 axis, and how drugs such as cyproheptadine agonize that pathway in order to prevent the reawakening that drives the growth of BrCa metastases in the bone, thereby increasing overall survival.

Citation Format: Irwin H. Gelman, Seamus Degan, Henry G. Withers, Subrahmanya Anirudh Kaligotla Venkata. The role of HBP1 in controlling breast cancer dormancy reawakening [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 3643.
Abstract 3647: Oncogenic Kras drives cancer-associated fibroblast heterogeneity and substate changes in pancreatic cancer
Authors: Thalappillil Jennifer S. , Caligiuri Giuseppina , Nadella Sandeep , Alagesan Brinda , Yordanov Georgi N. , Shakiba Mojdeh , Kaminow Benjamin , Hinds Juliene , Perez-Mancera Pedro A. , Preall Jonathan , Dobin Alexander , Park Youngkyu , Tuveson David A.
Published: June 2022

Pancreatic ductal adenocarcinoma (PDAC) is currently the third-leading cause of cancer-related deaths in the United States with no effective or targeted therapies to improve outcomes. Two defining features of PDAC are the dense stroma composing the bulk of the tumor mass and mutations in KRAS, the primary oncogene in most PDAC patients. Advances in knowledge on both fronts have led to promising avenues for therapeutics: recently described heterogeneity within the cancer-associated fibroblast (CAF) population residing in the stroma offers insight into the lack of success with therapies only targeting CAFs; and mutant KRAS inhibitors directed at the G12C isoform have received accelerated FDA approval for treatment of locally advanced and metastatic non-small cell lung cancer. However, the nature of this CAF heterogeneity is not yet fully understood, and any effects of KRAS blockade on the stroma have not been evaluated with consideration of this heterogeneity in mind. To assess how loss of Kras affects CAF heterogeneity and plasticity, we employed a genetically engineered mouse model (GEMM) of PDAC harboring a reversible oncogenic KrasG12V allele conditionally expressed from the endogenous Kras locus. This FPC compound mouse (KrasFrt-LSL-G12V-Frt; p53LSL-R172H; PDX-CRE; Rosa26FlpOERT2) spontaneously develops pancreatic lesions and allows for irreversible excision of the mutant Kras allele upon the application of Tamoxifen. Using single-cell RNA sequencing (scRNAseq), fluorescence in situ hybridization, and functional in vitro and in vivo approaches, we found that oncogenic Kras ablation led to tumor regression and altered cancer cell gene programs, profoundly affecting the tumor microenvironment, specifically CAF heterogeneity. Mutant Kras loss leads to decreased Tgfb1 expression in the cancer cells, but surprisingly also to increased Il1a levels, correlating with a reduction in myofibroblastic CAFs (myCAFs) and an expansion in inflammatory CAFs (iCAFs), respectively. Our results suggest that mutant Kras drives paracrine signaling that shapes CAF heterogeneity and should be considered for the development of the most effective therapeutic strategies.

Citation Format: Jennifer S. Thalappillil, Giuseppina Caligiuri, Sandeep Nadella, Brinda Alagesan, Georgi N. Yordanov, Mojdeh Shakiba, Benjamin Kaminow, Juliene Hinds, Pedro A. Perez-Mancera, Jonathan Preall, Alexander Dobin, Youngkyu Park, David A. Tuveson. Oncogenic Kras drives cancer-associated fibroblast heterogeneity and substate changes in pancreatic 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 3647.
Abstract 3679: A qualitative analysis of coping with genetically exacerbated risk of breast and ovarian cancers among medically-underserved women with BRCA1/2 mutations
Authors: Tredway Kristi , Dibble Kate E. , Connor Avonne E.
Published: June 2022

Individuals testing positive for BRCA1/2 genetic mutations, or hereditary breast and ovarian cancer mutations, are 33-55% more likely than women without these mutations to develop breast and/or ovarian cancers before the age of 70. While research involving these genetic mutations continues to emerge, there remains unanswered questions regarding prophylactic experiences and subsequent impacts on mental health within subgroups of BRCA1/2-positive women. The purpose of this analysis was to explore the impact of BRCA1/2 mutations, prophylactic surgeries, and surveillance regimens within the scope of everyday life within a sample of BRCA1/2 positive women from medically-underserved backgrounds living in the United States (US). A sample of 211 US adult women who have tested positive for BRCA1/2 mutations within the past 5 years and who identify with one or more medically-underserved populations (racial, ethnic, or sexual minority, person with a physical disability, chronically-ill, those in poverty, immigrant populations) elucidated compelling qualitative data. A total of 169 (80.1%) women completed open-ended questions at the end of the online survey. Thematic analysis was utilized to identify themes and subthemes concerning mental health, sources of stress, and methods of stress relief. The focus of the current analysis is on the sources of stress identified by the respondents. Fourteen subthemes were identified. The four most common stressors were concerns about post-treatment recovery (19% of respondents), recurrence of a new cancer (15%), medical unknown of having a genetic mutation that increases the risk of cancer (14%), and having to schedule and plan for continual surveillance (12%). The next five subthemes ranged from 7-9% and include waiting for medical results, personal finances and covering medical expenses, impact of the COVID-19 pandemic, pre-operative anxiety, and worrying about insurance coverage. Our findings support previous research on cancer stressors for women while adding important qualitative elements for a richer understanding. Furthermore, since much of the research on the lived experiences of BRCA1/2 has been on highly-educated, non-Hispanic white women, few studies have focused entirely on medically-underserved populations, which was the entirety of our sample. This work adds an important intersectional lens in which to better understand the experiences of living with a BRCA1/2 mutation.

Citation Format: Kristi Tredway, Kate E. Dibble, Avonne E. Connor. A qualitative analysis of coping with genetically exacerbated risk of breast and ovarian cancers among medically-underserved women with BRCA1/2 mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3679.
Abstract 3747: RPS3 positively regulates nucleotide excision repair with respect to XP-D and skin cancers
Authors: Kim Joon , Park Yong-Joon , Kim Tae Sung , Ahn Woo Sung , Kim Hag Dong
Published: June 2022

Ribosomal protein S3 (rpS3) is a multifunctional protein working in translation, DNA repair, cancer, apoptosis etc. UV induced DNA damage is repaired by the nucleotide excision repair (NER) pathways; defects in these pathways lead to a genetic instability known as xeroderma pigmentosum (XP) eventually developing skin cancers. We discovered that rpS3 associates with transcription factor IIH (TFIIH) via an interaction with the xeroderma pigmentosum complementation group D (XPD) protein and complements its function in the NER pathway. Here, we showed that XP-D cells overexpressing rpS3 showed markedly increased resistance to UV through XPD and rpS3 interaction thus augmenting the helicase activity of XPD protein. Additionally, the knockdown of rpS3 caused reduced NER efficiency and the subsequent addition of rpS3 restored the helicase activity of the TFIIH complex in cells. We present data suggesting that rpS3 is involved in post-excision processing in NER, assisting TFIIH in expediting the repair process by increasing its turnover rate when DNA is damaged. We also propose that rpS3 is a novel accessory protein of the NER pathway and its recruitment to the repair machinery upon UV damage augments repair efficiency by enhancing XPD helicase function and increasing its turnover rate, thus facilitating DNA repair. In addition to this, manipulations of rpS3 gene could complement XP-D phenotype and prevent UV damage and skin cancer occurrence. Animal studies strongly indicate that these result could be applied not only for the development of cancer drugs but also for cosmeceuticals. [1] FASEB J. (2020) 34: 8102 [2] Cell & Mol Life Sci (2021) 78: 3591

Citation Format: Joon Kim, Yong-Joon Park, Tae Sung Kim, Woo Sung Ahn, Hag Dong Kim. RPS3 positively regulates nucleotide excision repair with respect to XP-D and skin 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 3747.