bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3123: Targeting SHP2 and RAS MAPK pathway in neuroblastoma
Authors: Valencia-Sama Ivette , Adderley Teresa , Kee Lynn , Christopher Gabriella , Kano Yoshihito , Ohh Michael , Irwin Meredith
Published: August 2019

Introduction: Neuroblastoma (NB), the most common pediatric extra-cranial solid tumor, recurs in >50% of patients who present with metastases. Strategies to treat relapsed NB, which is often fatal, include targeting relapse-specific signaling pathways. Recently, sequencing studies have revealed that 78% of mutations detected in relapse samples are predicted to activate the RAS-MAPK pathway, suggesting there may be opportunities to pharmacologically target this pathway to treat recurrent NB.

Experimental Design: Our lab previously reported that the PTPN11-encoded tyrosine phosphatase SHP2 is an activator of the RAS pathway, and pharmacologic inhibition of SHP2 inhibited glioblastoma growth in vivo. To determine whether inhibiting SHP2 in NB would impact tumor growth we treated a panel of NB cells with diverse genetic backgrounds, including mutations in NRAS, with different SHP2 inhibitors (SHP099 and II-B08) alone and in combination with additional drugs that target RAS-MAPK signaling.

Results: In comparison to NB cell lines harboring endogenous NRAS mutations (NRASmt), cells with NRAS wild-type (NRASwt) were more sensitive to SHP2 inhibitors. In addition, NRASwt cells engineered to overexpress NRASmt were more resistant to SHP099 than cells with endogenous or overexpressed NRASwt, as demonstrated by higher levels of proliferation, increased survival, and diminished apoptosis. Furthermore, SHP099 effectively inhibited SHP2 in both NRASwt and NRASmt cells, but only failed to inactivate the downstream RAS effector ERK1/2 in NRASmt cells, suggesting that SHP099 treatment alone is ineffective in cells harboring NRAS mutations. To determine whether SHP099 resistance in NRASmt cells could be overcome with combination strategies, sensitive and resistant NB cells were treated with SHP2 inhibitors alone or in combination with other RAS-MAPK pathway inhibitors (vemurafenib, trametinib and ulixertinib). Interestingly, in comparison to SHP099 or II-B08 alone, all three combinations significantly reduced survival and IC50 values in both NRASwt and NRASmt cells. Using the Bliss independence model we determined all three combinations were synergistic.

Conclusions: Our studies demonstrate that NRAS mutations are associated with resistance to SHP2 inhibitors, and that in certain tumors, based on the genetic status of RAS-MAPK-SHP2 signaling components, combinations of drugs targeting this pathway could be effective strategies for relapsed NB.

Citation Format: Ivette Valencia-Sama, Teresa Adderley, Lynn Kee, Gabriella Christopher, Yoshihito Kano, Michael Ohh, Meredith Irwin. Targeting SHP2 and RAS MAPK pathway in neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3123.
Abstract 3133: Leukocyte telomere length, cancer incidence and all-cause mortality among Chinese adults: Singapore Chinese health study
Authors: Samavat Hamed , Luu Hung N. , Wang Renwei , Jin Aizhen , Koh Woon-Puay , Yuan Jian-Min
Published: August 2019

Background: Telomeres play a key role in the chromosomal maintenance and stability. To date, very few studies have investigated the association between leukocyte telomere length with cancer incidence and all-cause mortality, particularly among Asian population.

Methods: Relative telomere lengths in genomic DNA from peripheral blood samples were quantified using a validated quantitative real-time PCR among 26,540 middle-aged or older Chinese adults. Hazard ratios (HRs) and 95% confidence intervals (CIs) of incident cancer and deaths by quintiles of telomere length were calculated using the Cox proportional hazards regression method with adjustment for potential confounders.

Results: During 13.2 years of follow-up, 4,353 individuals developed cancer and 2,660 participants died of cancer. Participants with the longest telomeres had significantly 16% higher risk of developing cancer compared to those with the shortest telomeres after controlling for established risk factors (95% CI: 1.06, 1.28; Ptrend= 0.0003). We found similar pattern of results for lung adenocarcinoma (HRQ5 vs. Q1=2.89; 95% CI: 1.95, 4.27), pancreatic cancer (HRQ5 vs. Q1=2.36; 95% CI: 1.29, 4.32), kidney cancer (HRQ5 vs. Q1=3.23; 95% CI: 1.47, 7.53), and genitourinary system cancers including kidney, renal pelvis, ureter, and bladder (HRQ5 vs. Q1=1.56; 95% CI: 1.02, 2.39). In contrast, longer telomeres were associated with lower risk of overall death (HRQ5 vs. Q1=0.93; 95% CI: 0.86, 1.00), and deaths due to ischemic heart disease (HRQ5 vs. Q1=0.85; 95% CI: 0.70, 1.02), respiratory disease (HRQ5 vs. Q1=0.76; 95% CI: 0.64, 0.91), non-cancer (HRQ5 vs. Q1=0.80; 95%: 0.73, 0.88) and other diseases (HRQ5 vs. Q1=0.77; 95% CI: 0.63, 0.94).

Conclusion: The findings of this cohort study support the hypothesis that longer telomere length may be a risk factor for cancer and cancer-related deaths, but might have opposing impact on overall survival.

Funding Sources: National Institutes of Health (NIH) (R01 CA144034 and UM1 CA182876); NIH/NCI T32CA186873; National Medical Research Council, Singapore (NMRC/CSA/0055/2013); NIH (P20CA210300).

Citation Format: Hamed Samavat, Hung N. Luu, Renwei Wang, Aizhen Jin, Woon-Puay Koh, Jian-Min Yuan. Leukocyte telomere length, cancer incidence and all-cause mortality among Chinese adults: Singapore Chinese health study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3133.
Abstract 3151: Quantitative measurement of Siglec-15 expression in non-small cell lung cancer and its association with PD-L1, B7-H4 and tumor infiltrating lymphocytes
Authors: Toki Maria , Zugazagoitia Jon , Altan Mehmet , Liu Linda , Mani Nikita , Liu Yuting , Syrigos Konstantinos , Chen Lieping , Langermann Solomon , Herbst Roy , Rimm David
Published: August 2019

Introduction: Siglecs are sialic acid-binding transmembrane receptors that regulate the functions of innate and adaptive immune system through the recognition of glycan ligands. Siglec-15 has been recently described as an immune suppressive molecule that shares molecular structure with PD-L1, but its role in NSCLC is still unknown. In this study, we determined Siglec-15 expression in three retrospective NSCLC cohorts and evaluated its association with mutation status, major clinicopathologic characteristics and survival.

Experimental procedures: We used multiplexed automated quantitative immunofluorescence (QIF) to develop a validated assay for Siglec-15 measurement and used it to assess Siglec-15 expression and its association to major clinicopathologic variables and survival in three NSCLC cohorts of over 600 patients. Additionally, we investigated the correlation of Siglec-15 expression with tumor-infiltrating lymphocytes, PD-L1, B7-H3 and B7-H4 tumor expression.

Results: In our study, Siglec-15 tumor positivity was found in 12.5%, 13.7% and 22.8% of NSCLC cohort patients. Siglec-15 expression was higher in EGFR mutant and EGFR/KRAS wild type tumors compared to KRAS mutants but was not associated with any other major clinicopathological characteristics. Siglec-15 followed a mutually exclusive pattern of expression with PD-L1, B7-H3 and B7-H4 (co-expression in 3.1%, 13.2% and 7.7% of the patients respectively), while high levels were not correlated with lymphocyte infiltration or T-cell activation, suggesting a different upregulation mechanism not mediated by IFN-gamma.

Conclusions: Siglec-15 is a protein expressed with high frequency in NSCLC. Co-expression of Siglec-15 with PD-L1, B7-H3 and B7-H4 is relatively rare, suggesting that Siglec-15 has distinct and non-redundant features compared to other B7 family members.

Citation Format: Maria Toki, Jon Zugazagoitia, Mehmet Altan, Linda Liu, Nikita Mani, Yuting Liu, Konstantinos Syrigos, Lieping Chen, Solomon Langermann, Roy Herbst, David Rimm. Quantitative measurement of Siglec-15 expression in non-small cell lung cancer and its association with PD-L1, B7-H4 and tumor infiltrating lymphocytes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3151.
Abstract 3153: Prostatic acid phosphatase (PAP) predictive effect for prostate cancer in a population-based study: The renewal of PAP
Authors: Wang Fubo , Xu Huan , Sun Yinghao
Published: August 2019

Objective: Use prostatic specific acid phosphatase (PAP) to characterize the disease progression and median survivals of patients with prostate cancer (PCa) based on the analysis in a population-based study from Surveillance, Epidemiology, and End Results (SEER) database.

Materials and Methods: PCa patients with completed PAP results were selected from the SEER database of the National Cancer Institute. Mann-Whitney Sum test was utilized to compare the statistical significance for measurement data and ranked data, which were stratified by age, race, TNM Classification of Malignant Tumors (TNM), pathological grades, number of tumors, PAP and survival duration. Logistic analysis was performed to identify predictors of the presence of invasion and metastases. Cox regression was utilized to analyze the factors associated with all-cause mortality and prostate-cancer specific mortality. Moreover, survival curve was also present.

Results: In total, there are 5184 PAP+ patients and 3161 PAP- patients involved in this study. The Mann-Whitney Sum test showed that slightly greater tumor size(p=0.03), elevated lymphatic (p=0.005) and distant (p<0.001) metastases rate, higher pathologic grade(p<0.001), localized tumor number (p<0.001), shortened survival months (p<0.001) were observed in the PAP+ group compared with the PAP- group. In the Multivariable Logistic Regression, invasion and metastases Hazard Ratio (HR) were elevated significantly (p<0.001) in the PAP+ individuals. In the survival analysis, PAP- patients experience the prolonged median survival. In the post-surgical patients, the survival months were still longer in PAP+ patients compared with the negative ones (p<0.001), though surgery prolonged the survival months of both groups. Survival months stratified by localized, invasion and metastases situations were analyzed. In the three stratified sub-groups, survival duration is significantly decreased in the PAP+ individuals in the localized PCa group (P<0.001**) and the metastases group (P=0.013).

Conclusions: The findings of this study provide population-based estimates of the PCa progress and prognosis for patients with different PAP results, which may suggest a renewed period for the PAP.

Citation Format: Fubo Wang, Huan Xu, Yinghao Sun. Prostatic acid phosphatase (PAP) predictive effect for prostate cancer in a population-based study: The renewal of PAP [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3153.
Abstract 3154: Tumor expression of Activin A is associated with clinical outcomes in patients with colorectal cancer
Authors: Daitoku Nobuya , Miyamoto Yuji , Sakamoto Yuki , Etoh Kojiro , Hiyoshi Yukiharu , Nagai Yohei , Iwatsuki Masaaki , Ishimoto Takatsugu , Baba Yoshifumi , Iwagami Shiro , Yoshida Naoya , Baba Hideo
Published: August 2019

Background:

Activin A is a member of the transforming growth factor β (TGF-β) superfamily. Activin A shows an extensive variety of biological activities, including mesoderm induction, bone remodeling, muscle atrophy. Activin A is also related to Smad 2/3 mediated cancer development and metastasis. The overexpression of Activin A has been reported in several types of cancers and high expression of Activin A leads to poor prognosis. We examined the relationship between tumor expression of Activin A and clinical outcomes in patients with colorectal cancer.

Methods:

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We analyzed the association between tumor expression of Activin A and clinicopathological features and patient’s prognosis in 157 primary colorectal cancers, which were curatively resected between 2008 and 2012. The expression level of Activin A was measured in tumor tissue by quantitative RT-PCR. Patients were categorized into the high or low groups based on median expression value of Activin A and Kaplan-Meier survival analyses were performed to display difference in overall survival (OS) and relapse-free survival (RFS) between two groups. The between-group differences were assessed by the log-rank test and stepwise multivariate Cox regression analysis was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for OS.

Result:

RT-PCR analysis showed that expression of Activin A was significantly higher in tumor areas compared with that in normal (p<0.001). Activin A was highly expressed in the rectal cancer (p=0.015). Other clinicopathological factors were not significantly correlated with Activin A expression. Patients with Activin A high-expressed colorectal cancers showed a significantly shorter OS and RFS than those with activin A low-expressed tumor (5-year OS: Low 79.2% vs High 63.8%, p=0.037). High expression of Activin A is an independent predictor of poor prognosis in patients with colorectal cancers after curative surgery (Low vs High, HR=5.558, 95%CIs=2.229-15.17,

AACR Annual Meeting 2019

p=0.003).

Conclusion:

We concluded that high Activin A expression in tumor is associated with poor prognosis in colorectal patients.

Citation Format: Nobuya Daitoku, Yuji Miyamoto, Yuki Sakamoto, Kojiro Etoh, Yukiharu Hiyoshi, Yohei Nagai, Masaaki Iwatsuki, Takatsugu Ishimoto, Yoshifumi Baba, Shiro Iwagami, Naoya Yoshida, Hideo Baba. Tumor expression of Activin A is associated with clinical outcomes in patients with colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3154.
Abstract 3180: Targeting peptide-loaded-DC CIK cells induce a specific antitumor response
Authors: Zhu Yimin , Cui Xueyuan , Liu Cuijuan
Published: August 2019

Currently, immunotherapy has become an effective alternative therapeutic approach for cancers. Cytokine-induced killer (CIK) cells have a higher proliferation rate, increased efficacy with few side-effects, and non- MHC-restricted killing after co-culturing with dendritic cells (DCs). However, the specificity and efficacy of DC-CIK treatment still need to be improved. In our study, the antitumor effects of CIK cells co-culturing with DCs pulsed with non-cell derived targeting peptides, which could specifically bind to certain tumor cells, were evaluated. Our results indicated that targeting peptide-loaded DCs could enhance the differentiation and cytotoxicity of CIK cells. CIK cells, which were treated with specific targeting peptide-loaded DCs, could effectively and specifically kill tumor cells in vitro and in vivo, as long as tumor cells were pre-treated with these targeting peptides. Moreover, the CIK cytotoxic effect of this type acquired a certain properties of memory and resistance to the tolerance. In conclusion, targeting peptides could guide DC-CIK more effectively and specifically kill tumor cells and this non-cell derived targeting peptide-loaded-DC CIK may work as a novel means for cancer therapy.

Citation Format: Yimin Zhu, Xueyuan Cui, Cuijuan Liu. Targeting peptide-loaded-DC CIK cells induce a specific antitumor response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3180.
Abstract 3198: Therapeutic potential of MET inhibitor combined with immune checkpoint blockade in pancreatic cancer
Authors: Gao Mei , Lin Miranda , Yang Yachao , Kim Joseph
Published: August 2019

Novel Combination Therapeutic Targeting of the Immune Checkpoint PD-1 and c-MET in Pancreatic Cancer

Introduction: Therapeutic regimens incorporating immune checkpoint inhibitors (ICIs) have improved survival in many cancers, but have had little impact in pancreatic ductal adenocarcinoma (PDAC). We previously discovered that these ICIs directly target autonomously expressed and functional PD-1 on PDAC cells. We sought to investigate downstream effectors of PD-1 signaling in PDAC cells as potential novel therapeutic targets.

Methods: We performed a Phospho Explorer Array, which measures the levels of over 200 phospho-specific antibodies and their corresponding total proteins, to determine activated signaling pathways following exposure of PDAC cells to PD-L1 (the ligand for PD-1). Upon detecting upregulation of PD-1 mediated MET signaling, we verified MET pathway activation by exposing PDAC cells (MIAPaCa-2 and PANC-1) to PD-L1 and measuring levels of phosphorylated MET by immunoblotting. Then, we tested whether the MET small molecule inhibitor blocked PD-1 mediated MET signaling. Finally, PDAC patient-derived organoids (PDOs) were utilized to test the cytotoxicity of ICIs alone or in combination with cabozantinib.

Results: The phospho-protein array revealed 10-fold upregulation of MET activity followed exposure of PDAC cells to PD-L1. Western blot assay verified increased levels of MET phosphorylation that varied in a time-dependent manner following PD-L1 treatment in both PANC-1 and MIAPaCa-2 cell lines. Pre-treatment of PDAC cells with cabozantinib completely blocked PD-1/PD-L1 mediated MET phosphorylation. By CellTiter-Glo assay the IC50 of cabozantinib was calculated in MIAPaCa-2 and PANC-1 cells as 9.5 µM and 8.6 µM, respectively. Combining cabozantinib with clinical grade anti-PD-1 monoclonal antibodies nivolumab and pembrolizumab revealed synergistic cytotoxicity in PDAC cells and PDOs.

Conclusion: In these preliminary studies, we report PD-1 activation of the MET pathway and synergy killing of PDAC cancer models with novel combination therapy of cabozantinib and ICIs in PDAC. This positive data warrants further exploration of the interaction of MET with the PD-1/PD-L1 axis and its role in PDAC progression.

Note: This abstract was not presented at the meeting.

Citation Format: Mei Gao, Miranda Lin, Yachao Yang, Joseph Kim. Therapeutic potential of MET inhibitor combined with immune checkpoint blockade in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3198.
Abstract 3218: Anti-PD1 and -CTLA-4 combination in vivo enhances DC-based tumor-associated mitochondria antigen immunotherapy efficacy
Authors: Perales-Linares Renzo F. , Pierini Stefano , Uribe Mireia , Pustylnikov Sergei , Costabile Francesca , Beghi Silvia , Facciabene Andrea
Published: August 2019

Somatic mitochondria DNA (mtDNA) abnormalities have been identified in various types of human cancers. Previously, we generated tumor protective immunity under prophylactic and therapeutic approaches employing a murine kidney tumor model system and dendritic cell (DC)-based vaccination containing RENCA-derived mitochondria enriched lysates. Our results shown that tumor-associated mitochondria antigens (TAMAs) are targetable antigens for cancer immunotherapy (PMID: 26378078). Preliminary data also revealed increased endogenous PD-L1 mRNA expression levels in RENCA tumors of treated mice versus healthy kidney tissue. To investigate the impact of PD1/PD-L1 axis antagonism, Balb/C mice were challenged with RENCA cells at day 0 followed by TAMA-vaccination at day 3 and concurrent administration of anti-PD1 (aPD1) 5 times every 3 days. Interestingly, the aPD1-TAMA treatment resulted in reduced tumor growth, greater T CD4+ and T CD8+ cell infiltration, and lower intratumoral-MDSC as compared to the TAMA vaccine alone. In addition, we observed higher T cell activation from the aPD1-TAMA group upon co-culture with bone marrow-derived dendritic cells exposed to RENCA mitochondria lysate, suggesting that the inhibition of PD1 also enhanced the immunogenicity of the TAMA vaccine. Further analysis of the tumor environment revealed that the PD1-PD-L1 axis antagonism correlated with an increment of intratumoral CTLA4 expression and recruitment of T regulatory (Treg) cells. We introduced a third arm of treatment including a CTLA4 antagonist antibody in combination with aPD1 and TAMA vaccine in vivo. Strikingly, the tumor progression was greatly impacted causing tumor rejection in the majority of tumor-bearing animals, sustained tumor volume reduction in the others, a decrease in Treg cell recruitment, and concomitant increment of T CD8+ cell infiltration and activation. Altogether, the combination of check point inhibitors in vivo significantly improved the efficacy of the TAMA immunotherapy by remodeling the tumor microenvironment, reducing the immunosuppressive potential, and facilitating the infiltration of effector T cells into the tumor.

Citation Format: Renzo F. Perales-Linares, Stefano Pierini, Mireia Uribe, Sergei Pustylnikov, Francesca Costabile, Silvia Beghi, Andrea Facciabene. Anti-PD1 and -CTLA-4 combination in vivo enhances DC-based tumor-associated mitochondria antigen immunotherapy efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3218.
Abstract 3226: The IRF8-osteopontin-CD44 axis functions as an immune checkpoint to control CD8+ T cell activation and tumor immune evasion
Authors: Klement John D. , Paschall Amy V. , Redd Priscilla S. , Ibrahim Mohammed L. , Lu Chunwan , Yang Dafeng , Celis Esteban , Abrams Scott I. , Ozato Keiko , Liu Kebin
Published: August 2019

Despite breakthroughs in immune checkpoint inhibitor (ICI) immunotherapy, not all human cancers respond to ICI immunotherapy and only fraction of patients with responsive tumors have a durable response to current ICI immunotherapy. This clinical conundrum suggests that additional immune checkpoints may exist, particularly in cancers resistant to current ICI immunotherapy, such as colorectal cancer. We report here that interferon regulatory factor 8 (IRF8) deficiency led to impairment of cytotoxic T lymphocyte (CTL) activation in a peptide vaccine model and allowed allograft transplant tumor tolerance. These effects were associated with upregulation of the CTL surface marker CD44. However, analysis of chimeric mice with competitive reconstitution of wild type and IRF8 KO bone marrow cells as well as mice with IRF8 deficiency only in T cells indicated that IRF8 plays no intrinsic role in CTL activation. Instead, IRF8 functioned as a repressor of osteopontin (OPN), the physiological ligand for CD44 on T cells, in CD11b+Ly6CloLy6G+ myeloid cells and OPN acted as a potent T cell suppressor. In vitro stimulation of CTLs in the presence of OPN resulted in decreased expression of activation markers CD69 and CD25 and inhibited proliferation and interferon gamma (IFNg) secretion. Expression of OPN was found to be upregulated in both myeloid cells and colon epithelial cells following silencing of IRF8 expression. IRF8 bound to the Spp1 promoter, which encodes OPN, to repress OPN expression in colon epithelial cells. Correspondingly, human colon carcinoma cells exhibited decreased IRF8 and increased OPN expression. These increased OPN levels inhibited human PBMC proliferation and IFNg secretion. The elevated expression of OPN in human colon carcinoma was correlated with decreased patient survival. Our data indicates that myeloid and tumor cell-expressed OPN acts as a novel immune checkpoint to suppress T cell activation and confer host tumor immune tolerance. Blockade of this checkpoint may expand the pool of patients who may benefit from ICI immunotherapy.

Citation Format: John D. Klement, Amy V. Paschall, Priscilla S. Redd, Mohammed L. Ibrahim, Chunwan Lu, Dafeng Yang, Esteban Celis, Scott I. Abrams, Keiko Ozato, Kebin Liu. The IRF8-osteopontin-CD44 axis functions as an immune checkpoint to control CD8+ T cell activation and tumor immune evasion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3226.
Abstract 3235: Activation-inducible TNFR family receptor (AITR) signaling mediates the polarization of CD4+ T cells into Th1, Th2, and Th17, converts Treg to Teff and eradicates solid tumors
Authors: Kwon Byoung S. , Lee Seung J. , Kim Young H. , Lee Joong W. , Hwang Sun H. , Vinay Dass S.
Published: August 2019

AITR (activation-inducible TNFR family receptor, human GITR), an inducible costimulatory receptor of human T cells, is expressed constitutively on Treg and inducible on Teff upon antigen engagement. AITR co-stimulates T cell activation and recruits certain members of TRAF family upon interaction with its ligand. We examined whether the stimulation of distinct regions of extracellular domain of AITR can generate signals that promote different subsets of CD4+ T cells. We found that crosslinking AITR by agonistic anti-AITR Abs (A27, A41, and A35), that recognize three distinct regions of the extracellular domain, polarize CD4+ T cells into Th1, Th2 and Th17, respectively. The subset polarization evoked by these antibodies was the result of recruitment of specific TRAFs, phosphorylation of distinct STATs and expression of Th subset fate-determining master regulatory genes. Stimulation with A27 recruited TRAF-1 and -2, activated STAT-1, -4 and JNK1/2, and induced transcription factor T-bet. On the other hand, activation with A35 recruited TRAF-6, activated STAT-3 and p38 MAPK, and induced RORγt. In contrast, A41 recruited TRAF-3 and -5, activated STAT-5, -6 and ERK1/2, and produced GATA-3. Remarkably, A27 induced the conversion of CD25+Foxp3+ Treg cells to IFN-γ-producing Th1 cells with a concomitant suppression of Foxp3 and TGF-β expression both in healthy individuals as well as cancer patients. A35 also, but not A41, suppressed the expression of Foxp3 and induced IL-17 in Treg cells. A27 alone, but not others produced a strong anti-tumor effect in a human tumor xenograft model of humanized mice in an IFN-γ- and Treg conversion-dependent mechanism. Taken together, the data that AITR regulates Th subset polarization and eradicates solid tumors can be a target for broad-spectrum immune check point therapeutics against cancers and autoimmune diseases.

Citation Format: Byoung S. Kwon, Seung J. Lee, Young H. Kim, Joong W. Lee, Sun H. Hwang, Dass S. Vinay. Activation-inducible TNFR family receptor (AITR) signaling mediates the polarization of CD4+ T cells into Th1, Th2, and Th17, converts Treg to Teff and eradicates solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3235.
Abstract 3237: Combinatorial immune checkpoint inhibitor therapy in anaplastic thyroid cancer
Authors: Chakraborty Sanjukta , Maniyar Rachana R. , Dadafarin Sina , Rahoma Ghada Ben , Singh Sarnath , Moscatello Augustine , Geliebter Jan , Tiwari Raj K.
Published: August 2019

Anaplastic thyroid cancer(ATC) is a rare but extremely aggressive form of endocrine malignancy that accounts for only 1-2% of total thyroid cancer cases but responsible for 20-30% of annual mortality from thyroid cancer in the USA. Genetic lesion landscape in ATC is not conducive to multiple targeted therapies. BRAF mutation is one of the dominant genetic lesions observed in 30-40% of ATC cases and 98% of them are BRAFV600E positive. Due to the limited therapeutic efficacy of BRAFV600E inhibitor vemurafenib, identification of novel therapeutic candidates would provide a viable alternative. Immunecheckpoint therapies have showed huge promise in recent years but are relatively underexplored in ATC patients. To this end, 4 ATC cell lines 8505C, T238, SW1736 and HTh74; 3 PTC cell lines TPC-1, BCPAP and K1 and 1 FTC cell line CGTH-W-1 were screened for expression of 29 immune-checkpoint molecules by qRT PCR with or without 10μM vemurafenib treatment for 24 hrs. Initial screening revealed a differential expression level of the transcripts among the cells. Vemurafenib treatment further up regulated expression of CD160, HVEM, BTLA, TIM3 and galectin9 in cell lines positive for BRAFV600E mutation (8505C, SW1736, BCPAP) and the ones harboring an additional PIK3CA mutation (T238, K1). This observation was further confirmed by immunocytochemistry. CD160 was not detected in any of the cell lines except for K1, TPC-1 and NTHY at protein level. Flow cytometry confirmed presence of BTLA, HVEM and TIM3 on the surface of these tumor cells which would enable them to engage their cognate ligands on T cells and suppress antitumor immune response. Western blots confirmed upregulation of BTLA, HVEM, TIM3 and galectin 9 in response to vemurafenib in both BRAFV600E positive cell lines and HTh74. Expression of these molecules were also validated by immunohistochemistry in patient samples. In an effort to evaluate the functional activity of these immunecheckpoint molecules, co-culture studies were done. Both HVEM and BTLA showed immunomodulatory capability and were capable of redirecting T cell differentiation towards a suppressive phenotype. Preclinical studies with combination of BRAFV600E or PI3K inhibitor and antagonistic antibodies against these molecules are currently underway. This study has identified two novel immune checkpoint molecules in ATC and might provide viable therapeutic targets.

Citation Format: Sanjukta Chakraborty, Rachana R. Maniyar, Sina Dadafarin, Ghada Ben Rahoma, Sarnath Singh, Augustine Moscatello, Jan Geliebter, Raj K. Tiwari. Combinatorial immune checkpoint inhibitor therapy in anaplastic thyroid cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3237.
Abstract 3246: Dynamics of T-cell checkpoint receptor profiles during melanoma progression
Authors: Edwards Jarem , Tasker Annie , Silva Inês Pires da , Quek Camelia , Allanson Benjamin M. , Saw Robyn P. M , Thompson John F. , Menzies Alexander M. , Palendira Umaimainthan , Wilmott James S. , Long Georgina V. , Scolyer Richard
Published: August 2019

Background A myriad of novel monoclonal antibody based immunotherapies targeting co-stimulating and co-inhibitory receptors have entered clinical trials in melanoma with the aim of increasing response rates and overcoming resistance to standard anti-CTLA-4 and anti-PD-1 immunotherapy. However, little is known about the abundance, co-expression and immune cells enriched for each specific drug target in the various stages of melanoma progression. Therefore, we sought to assess the relative abundance of checkpoint receptors and their expression during melanoma disease progression, as well as the immune cells enriched for each of these molecules.

Methods - Multiplex immunofluorescence staining for immune checkpoint receptors (ICOS, GITR, OX40, PD-1, TIM-3, and VISTA) was performed on 95 melanoma biopsies from 41 melanoma patients, including patient matched biopsies for primary, regional lymph node or distant metastases. - Mass cytometry was performed on leukocytes isolated from 18 treatment-naïve melanoma tumors to explore immune subsets enriched for many of the checkpoint receptors currently targeted in clinical trials.

Results & Conclusions GITR and OX40 were the least abundant checkpoint receptors in melanoma (p<0.001), with less than 1% of intra-tumoral T cells expressing either marker. TIM-3 and VISTA were mostly expressed on non-T cell populations, with TIM-3 enriched on dendritic cells. Tissue resident T cells (CD69+ CD103+ CD8+) represented a population highly enriched for TIGIT (>70%) and other co-inhibitory receptors but not co-stimulatory receptors. The proportion of GITR+ T cells decreases from primary melanoma (>5%) to patient matched lymph node (<1%, p=0.04) and distant metastases (<1%, p=0.0005). This data will underpin future clinical trial design and provide a rationale for combining these molecules in the clinic.

Note: This abstract was not presented at the meeting.

Citation Format: Jarem Edwards, Annie Tasker, Inês Pires da Silva, Camelia Quek, Benjamin M. Allanson, Robyn P. M Saw, John F. Thompson, Alexander M. Menzies, Umaimainthan Palendira, James S. Wilmott, Georgina V. Long, Richard Scolyer. Dynamics of T-cell checkpoint receptor profiles during melanoma progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3246.
Abstract 326: Enhanced efficacy of Sitravatinib (MGCD516) in metastatic models of antiangiogenic therapy resistance
Authors: Dolan Melissa , Mastri Michalis , Tracz Amanda , Christensen James G. , Chatta Gurkamal , Shi Yuhao , Ebos John M.
Published: August 2019

Tyrosine kinase inhibitors (TKIs) that primarily target vascular endothelial growth factor receptors (VEGFRs) are approved to treat several cancers in the metastatic setting. However, improvements in survival for most patients are short-lived and resistance is common. Sequential treatment or ‘switching’ from one VEGFR TKI to another has proven effective following failure in many instances. This may be due to broad drug-specific secondary TKI target profiles that can block metastasis- and angiogenesis-promoting processes. Here we examined sitravatinib (MGDC516), a novel small molecule TKI with activity against VEGFRs, that also can block Met, Axl, and several ephrin receptors (Eph), amongst several others. Transcriptomic and proteomic analysis showed multiple sitravatinib targets upregulated in VEGFR TKI-resistant mouse and human tumor cell lines derived from metastasis in mice. In vitro, sitravatinib treatment decreased proliferation in VEGFR TKI-resistant cells compared to untreated controls, suggesting prior RTKI resistance may enhance sitravatinib anti-tumor potency, while cabozantinib, a multi-targeted RTKI clinically approved after antiangiogenic therapy failure did not demonstrate enhanced anti-proliferative activity in resistant cells. In vivo, sitravatinib treatment significantly reduced orthotopically-implanted primary kidney and breast tumors in mice, with increased effects observed in VEGFR TKI-resistant tumors. Sitravatinib treatment was also found to suppress metastatic disease progression and improve survival in mice when continued after primary tumor removal, indicating metastasis-inhibiting effects of sitravatinib may be enhanced in VEGFR TKI-resistant settings. Together, these studies suggest that broad-spectrum RTKI inhibitors such as sitravatinib that target multiple metastasis-promoting mechanisms improve efficacy after antiangiogenic treatment failure and improve outcomes in a second-line setting.

Citation Format: Melissa Dolan, Michalis Mastri, Amanda Tracz, James G. Christensen, Gurkamal Chatta, Yuhao Shi, John M. Ebos. Enhanced efficacy of Sitravatinib (MGCD516) in metastatic models of antiangiogenic therapy resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 326.
Abstract 328: ADAM17-induced activation of HER receptors mediate resistance to trastuzumab in a subset of moderate HER2-expressing breast cancer cells
Authors: Feldinger Katharina , Vigneswara Vasanthy , Murphy Gillian , Kong Anthony
Published: August 2019

Currently anti-HER2 therapies are indicated for HER2-positive breast cancer patients that are IHC3+ or FISH positive. However, there have been studies suggesting that some HER2-negative patients may also respond to these treatments. Previously, our laboratory showed that trastuzumab upregulates ADAM17 and ADAM10 levels; and the resultant ligand release and the activation of HER receptors mediates trastuzumab acquired resistance in HER2-positive breast cancer. The aim of this study is to further understand the mechanisms of response and resistance of HER2 targeting agents such as trastuzumab and neratinib in low and moderate HER2-expressing breast cancer cells.

The HER2 expression of a panel of eight breast cell lines was assessed by IHC, FISH, western blot, and qRT-PCR. Using cell viability studies we found that in comparison with high (IHC 3+) and low HER2 expressing (IHC 0 or 1+) breast cancer cells, moderately expressing HER2 (2+) cells showed an intermediate response to trastuzumab and neratinib. Three moderate HER2-expressing breast cancer cell lines (IHC 2+), MDA-MB-361, MDA-MB-453 and HCC1569 were shown to respond to increasing doses of neratinib (with an IC50 less than 30nM). However, increasing doses of trastuzumab (up to 120 μg/ml) was unable to decrease the cell viability of these cells to below 50% of the control. The response to trastuzumab and neratinib correlated with basal ADAM17 but not ADAM10 expression. Trastuzumab treatment led to an upregulation of ADAM17 and the shedding of HER ligands in the media, as well as the phosphorylation of HER members. ADAM17 inhibition, using a specific anti-ADAM17 antibody or knockdown of the protein, decreased activation of HER members as well as downstream markers, correlating with reduced cell viability in moderate HER2-expressing cell lines. In addition, the combination of trastuzumab with neratinib was more effective than either single agent in moderate HER2-expressing cell lines.

Thus, ADAM17 may play a key role in the resistance to trastuzumab in moderate HER2-expressing breast cancer cells. Combining trastuzumab with an ADAM17 inhibitor or an irreversible pan-HER inhibitor such as neratinib may be an effective therapeutic strategy for targeting breast cancers with moderate HER2 expressing tumors.

Citation Format: Katharina Feldinger, Vasanthy Vigneswara, Gillian Murphy, Anthony Kong. ADAM17-induced activation of HER receptors mediate resistance to trastuzumab in a subset of moderate HER2-expressing breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 328.
Abstract 3280: TTFields induces immunogenic cell death and STING pathway activation through cytoplasmic double-stranded DNA in glioblastoma cells
Authors: Chen Dongjiang , Thomas Nagheme , Tran David D.
Published: August 2019

Glioblastoma (GBM) is the most common and deadliest malignant brain cancer in adults despite aggressive chemoradiotherapy. Tumor Treating Fields (TTFields) was recently approved in combination with adjuvant temozolomide chemotherapy for newly diagnosed GBM patients. The addition of TTFields resulted in a significant improvement in overall survival. TTFields are low-intensity alternating electric fields that are thought to disturb mitotic macromolecules’ assembly, leading to disrupted chromosomal segregation, integrity and stability. In many patients, a transient stage of increased peritumoral edema is often observed early in the course of TTFields treatment followed subsequently by objective radiographic responses, suggesting that a major component of therapeutic efficacy by TTFields may be an immune mediated process. However, the mechanism underlying these observations remains unclear. Here we report results on a panel of GBM cell lines treated with TTFields at the clinically approved frequency of 200 kHz using an in vitro TTFields system. Our data showed 24 hrs TTFields-treated GBM cells had a significantly higher rate (19.9% vs. 4.3%, p=0.0032) of micronuclei structures released into the cytoplasm as a result of TTFields-induced chromosomal instability. Nearly 40% of these micronuclei were co-localized with two upstream dsDNA sensors: absent in melanoma 2 (AIM2)andInterferon (IFN)-inducible proteinCyclic GMP-AMP synthase (cGAS), compared to absence of co-localization in untreated cells. TTFields-activated micronuclei-dsDNA sensor complexes led to i) induction of pyroptotic cell death, as measured by a specific LDH release assay, and through AIM2-recruited caspase1 and cleavage of pyroptosis-specific Gasdermin D; and ii) activation of STING pathway components including Type I IFNs and pro-inflammatory cytokines downstream of the NFκB pathway. GBM cell-specific shRNA depletion of either AIM2 or STING or both in a co-culture experiment of bone marrow cells or splenocytes with supernanants obtained from knockdown GBM cells was able to reverse the inducement of immune cells. These results provide compelling evidence that TTFields function as an activator of the immune system in GBM cells, and a strong rationale for combining TTFields with immunotherapy aimed at augmenting an anti-tumor immune response such as immune checkpoint inhibitors.

Note: This abstract was not presented at the meeting.

Citation Format: Dongjiang Chen, Nagheme Thomas, David D. Tran. TTFields induces immunogenic cell death and STING pathway activation through cytoplasmic double-stranded DNA in glioblastoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3280.
Abstract 3287: Survival disparities for second primary malignancies diagnosed among childhood cancer survivors: A population-based assessment
Authors: Brown Austin L. , Arroyo Vidal M. , Agrusa Jennifer , Scheurer Michael E. , Gramatges Maria M. , Lupo Philip J.
Published: August 2019

Background: Curative therapy places childhood cancer survivors at increased risk of second primary malignancies (SPMs). However, there have been few population-based attempts to characterize differences in outcomes between SPMs in childhood cancer survivors and comparable de novo first primary malignancies (FPMs).

Methods: We extracted clinical and demographic information from childhood cancer survivors who developed SPMs and from individuals with comparable de novo FPMs using the Surveillance, Epidemiology, and End Results (SEER) 1973-2015 database. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated with Cox proportional hazards models comparing overall survival (OS) between individuals with and without a history of childhood cancer. OS was evaluated overall and within specific cancers diagnosed in ≥50 childhood cancer survivors. Models accounted for potential confounders, including sex, race, age, decade of diagnosis, histology, and disease stage.

Results: Compared to individuals with FPMs (n=1,332,203), childhood cancer survivor with a similar SPM as the FPMs (n=1,409) experienced poorer OS (HR=1.86, 95%CI: 1.72-2.02) after accounting for age, sex, race, and decade of diagnosis. Estimated five-year overall survival for SPMs diagnosed in survivors of childhood cancer was 61.7% (95% CI: 58.9-64.4), compared to 77.4% (95% CI: 75.0-79.5) among de novo FPMs propensity score-matched on confounding factors. A history of childhood cancer remained a poor prognostic factor for all specific cancer evaluated, including: breast (HR=2.07, 95%CI: 1.63-2.62), thyroid (HR=3.59, 95%CI: 2.08-6.19), acute myeloid leukemia (HR=2.38, 95%CI:1.87-3.05), brain (HR=2.09, 95%CI:1.72-2.55), melanoma (HR=2.57, 95%CI: 1.55-4.27), bone (HR=1.88, 95%CI:1.37-2.57), and soft tissue sarcoma (HR=2.44, 95%CI: 1.78-3.33). Survival disparities were most pronounced in survivors diagnosed with a childhood cancer before age 10 (HR=2.83, 95%CI: 2.46-3.25), diagnosed with a SPM within 10 years of the childhood cancer (HR=2.61, 95%CI: 2.29-2.99), and exposed to radiotherapy during childhood (HR=2.13, 95%CI: 1.92-2.37).

Conclusion: Compared to individuals without a prior cancer diagnosis, survivors of childhood cancer with a SPM experience inferior outcomes. These survival disparities persist across cancer types, therapeutic exposures, and clinical factors.

Citation Format: Austin L. Brown, Vidal M. Arroyo, Jennifer Agrusa, Michael E. Scheurer, Maria M. Gramatges, Philip J. Lupo. Survival disparities for second primary malignancies diagnosed among childhood cancer survivors: A population-based assessment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3287.
Abstract 3290: Risk factors for post-radiotherapy pain in a multi-racial ethnic population of breast cancer patients: a prospective study
Authors: Lee Eunkyung , Snyder Shannon , Ip Edward , Wright Jean L. , Hu Jennifer J.
Published: August 2019

Cancer and/or treatment-related pain is a critical quality of life issue for cancer survivors. In a prospective longitudinal study of 1,000 breast cancer patients (enrolled during 2011-2013), we examined risk factors for pain among women undergoing adjuvant radiotherapy (RT). A pain score was assessed as a mean of four pain severity items (i.e., pain at its worst, least, average, and now) from the Brief Pain Inventory with an 11-point numeric rating scale (0-10) at baseline and post-RT. The study sample consists of 623 whites, 280 black/African Americans, 64 Hispanic whites, and 33 others. The mean age was 58.1 ±10.8 years and the mean body mass index (BMI) was 30.7 ±7.0 kg/m2. The mean pain score was 1.5 ±1.0 (baseline) and 2.5 ±1.8 (post-RT). In multivariable linear regression analysis (n= 863), post-RT pain score was significantly associated with baseline pain score (β= 0.39 per 1 point increment, p< 0.0001), age (β= -0.03 per 1 year increment, p< 0.001), BMI (β= 0.03 per 1 kg/m2 increment, p= 0.004), current smoking status (β= 0.57, p= 0.022), conventional RT fractionation (β= 0.48, p= 0.033), and pain medication use (β= 1.85, p< 0.0001). Further stratified analysis showed that post-RT pain score was associated with baseline pain score, age, BMI, and mastectomy among patients who did not use pain medication (n= 625); however, it was associated with baseline pain score and conventional RT fractionation among patients who did use pain medication (n= 238). Altogether, baseline pain score is the most significant and robust risk factor for post-RT pain, and conventional RT fractionation is a significant risk factor post-RT pain only among those who experienced more pain. These risk factors may help identify individuals at-risk for post-RT pain; thus, this information may help guide these high-risk individuals in their RT decision-making processes, such as considering a hypo-fractionated RT schedule.

Citation Format: Eunkyung Lee, Shannon Snyder, Edward Ip, Jean L. Wright, Jennifer J. Hu. Risk factors for post-radiotherapy pain in a multi-racial ethnic population of breast cancer patients: a prospective study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3290.