Citations

AbstractBackgroundThe accuracy of the eighth AJCC ypTNM staging system on the prognosis of gastric cancer (GC) patients after neoadjuvant therapy (NAT) is controversial. This study aimed to develop and validate a novel staging system using the log odds of positive lymph nodes scheme (LODDS).MethodsA retrospective analysis of 606 GC patients who underwent radical gastrectomy after neoadjuvant therapy was conducted as the development cohort. (Fujian Medical University Affiliated Union Hospital (n = 183), Qinghai University Affiliated Hospital (n = 169), Mayo Clinic (n = 236), Lanzhou University First Hospital (n = 18)). The validation cohort came from the SEER database (n = 1701). A novel ypTLoddsS (ypTLM) staging system was established using the 3‐year overall survival. The predictive performance of two systems was compared. ResultsTwo‐step multivariate Cox regression analysis in both cohorts showed that ypTLM was an independent predictor of overall survival of GC patients after neoadjuvant therapy (HR: 1.57, 95% CI: 1.30–1.88, p < 0.001). In the development cohort, ypTLM had better discrimination ability than ypTNM (C‐index: 0.663 vs 0.633, p < 0.001), better prediction homogeneity (LR: 97.7 vs. 70.9), and better prediction accuracy (BIC: 3067.01 vs 3093.82; NRI: 0.36). In the validation cohort, ypTLM had a better prognostic predictive ability (C‐index: 0.614 vs 0.588, p < 0.001; LR: 11,909.05 vs. 11,975.75; BIC: 13,263.71 vs 13,328.24; NRI: 0.22). The time‐dependent ROC curve shows that the predictive performance of ypTLM is better than ypTNM, and the analysis of the decision curve shows that ypTLM achieved better net benefits. ConclusionA LODDS‐based ypTLM staging system based on multicenter data was established and validated. The predictive performance was superior to the eighth AJCC ypTNM staging system.

Abstract Background: Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer-related death among women worldwide. Triple negative breast cancer (TNBC) represents 15-20% of all breast cancers and is an aggressive subtype. Chemotherapy-based treatments remain the standard of care for TNBC. Unfortunately, chemotherapy resistance is common, and for these patients, outcomes are poor and alternative treatment strategies remain an unmet need. circRNAs are a newly identified class of noncoding RNA molecules with covalently closed circular structures. An increasing number of recent studies including ours have indicated that circRNAs play crucial roles in regulating tumor development and chemoresistance. However, the role of circRNAs in the process of chemotherapy resistance and TNBC progression is not clear. Materials and Methods: As a first step towards identifying circRNAs that participate in the development of chemoresistance in TNBC cells, and to determine if targeting such circRNAs is a novel and efficacious therapeutic strategy, doxorubicin-resistant (Doxo-R), paclitaxel-resistant (PTX-R), and double-resistant (DP-R) cell lines were generated from MDA-MB-231. Human circRNA microarrays were utilized to profile the expression of approximately 14,000 known circRNAs in normal breast tissue, matched patient-derived xenografts (PDX) generated prior to and following neoadjuvant chemotherapy (NAC), and TNBC chemosensitive and chemoresistant cell lines. Top hits were validated using RT-PCR. Results: circRNA microarray profiling identified 429 and 310 transcripts differentially expressed in doxorubicin and paclitaxel resistant cells, respectively, compared to parental chemosensitive cell lines (|FC| ≥ 1.5; p value &lt; 0.05). In comparison to pre-NAC derived xenografts, 1,396 circRNAs were dysregulated among post-NAC PDX models. Further, three circRNAs (hsa_circ_001388, hsa_circ_104652, and hsa_circ_061260) were upregulated in Doxo-R, PTX-R, and post-NAC PDX samples compared to their respective controls. Among these three circRNAs, hsa_circ_001388 (also known as circNSD2) was the only transcript also predicted to be translated into a novel and uncharacterized protein given the presence of a high confidence translation initiation site and IRES sequence. Ongoing studies are aimed at determining the role of circNSD2 protein in breast cancer carcinogenesis, progression, and response to standard of care chemotherapeutics and the mechanistic process by which this protein functions. Additionally, the efficacy of specifically targeting this circRNA as a novel therapeutic approach is being explored. Conclusions: Increasing knowledge of the important functions of circRNAs underlying drug resistance will provide new opportunities for developing efficacious therapeutic strategies and prognostic/predictive biomarkers for TNBC. Citation Format: Xiyin Wang, Michael J. Emch, Xiaojia Tang, Jia Yu, Krishna R. Kalari, Liewei Wang, Matthew P. Goetz, John R. Hawse. The role of circular RNAs in triple negative breast cancer and chemotherapy resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1689.

Abstract Targetable drivers governing to 5-fluorouracil and cisplatin (5FU+CDDP) resistance remain elusive due to the paucity of physiologically and therapeutically relevant models. Accordingly, we established 5FU+CDDP resistant intestinal subtype GC patient-derived organoid lines. JAK/STAT signaling and its downstream, adenosine deaminases acting on RNA 1 (ADAR1), are shown to be concomitantly upregulated in the resistant lines. ADAR1 was demonstrated to confer chemoresistance and self-renewal in an RNA editing-dependent manner. WES-seq coupled with RNA-seq identified enrichment of hyperedited lipid metabolism genes in the resistant lines. Mechanistically, ADAR1-mediated A-to-I editing on 3’UTR of stearoyl-CoA desaturase (SCD1) increased binding of KH domain-containing, RNA-binding, signal transduction-associated 1 (KHDRBS1), thereby augmenting SCD1 mRNA stability. Consequently, SCD1 facilitates lipid droplet formation to alleviate chemotherapy-induced ER stress and enhances self-renewal through increasing β-catenin expression. Pharmacological inhibition of SCD1 abrogated chemoresistance and tumor-initiating cell frequency. Clinically, high proteomic level of ADAR1 and SCD1, or high SCD1 editing/ADAR1 mRNA signature score predicts a worse prognosis. Together, we unveiled a novel actionable target to circumvent chemoresistance. Citation Format: Jia Jian Loh, Tin Lok Wong, Shixun Lu, Helen HN Yan, Hoi Cheong Siu, Ren Xi, Dessy Chan, Max JF Kam, Lei Zhou, Man Tong, John A. Copland, Leilei Chen, Jingping Yun, Suet Yi Leung, Stephanie Ma. ADAR1-mediated RNA editing of SCD1 links lipid metabolism to gastric cancer drug resistance and self-renewal [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1755.

Abstract Zinc finger E-box–binding homeobox 1 (ZEB1) is a transcription factor that can promote tumor invasion and metastasis by inducing epithelial-to-mesenchymal transition (EMT). To date, regulation of ZEB1 by RAS/RAF signaling remains unclear, and few studies have examined posttranslation modification of ZEB1, including its ubiquitination. In human colorectal cancer cell lines with RAS/RAF/MEK/ERK activation, an interaction of ZEB1 with the deubiquitinase ubiquitin-specific protease 10 (USP10) was identified whereby USP10 modifies ZEB1 ubiquitination and promotes its proteasomal degradation. Regulation of the USP10–ZEB1 interaction by MEK–ERK signaling was shown whereby constitutive activation of ERK can phosphorylate USP10 at Ser236 to impair its interaction with ZEB1 and enable ZEB1 protein stabilization. Stabilized ZEB1 was shown to promote colorectal cancer metastatic colonization in a mouse tail vein injection model. Conversely, MEK–ERK inhibition blocked USP10 phosphorylation and enhanced the USP10–ZEB1 interaction shown to suppress ZEB1-mediated tumor cell migration and metastasis. In conclusion, we demonstrate a novel function of USP10 in the regulation of ZEB1 protein stability and its ability to mediate tumor metastasis in a preclinical model. Implications: The MEK–ERK-regulated interaction of USP10 with ZEB1 can promote the proteasomal degradation of ZEB1 and thereby suppress its demonstrated ability to mediate tumor metastasis.

Abstract Background: Oncogenic alterations (gene amplification, mutation, and fusion/rearrangements) of fibroblast growth factor receptor 2 (FGFR2) are rare and occur at varying frequencies across solid tumor types and have become critical therapeutic targets in drug development. First generation FGFR pan-kinase inhibitors non-selectively inhibit FGFR1-4 and are associated with dose limiting toxicities and narrow therapeutic windows. Off-isoform toxicity (FGFR1-hyperphosphatemia; FGFR4-diarrhea) and on-target acquired resistance have led to limited efficacy, which is primarily seen in FGFR2-fusion+ intrahepatic cholangiocarcinoma. Therapies that selectively target FGFR2 remain an unmet need in advanced breast cancer as well as other solid tumor types. RLY-4008 is a novel, oral FGFR2 inhibitor designed to overcome the limitations of pan-FGFR inhibitors (FGFRi) by potently and selectively targeting primary oncogenic FGFR2 alterations and acquired resistance mutations. RLY-4008 is &gt; 200-fold selective over FGFR1, &gt; 80- and &gt; 5000-fold selective over FGFR3 and FGFR4 respectively. Here we describe a phase 1/2 study to investigate the safety and antitumor activity in advanced FGFR2 altered cancers, including breast cancer. Methods: ReFocus is a phase 1/2 open label global study evaluating the safety and efficacy of RLY-4008 (NCT04526106) in adult patients with advanced unresectable and/or metastatic cancers harboring an FGFR2 alteration. Key eligibility criteria include: documented FGFR2 alteration in blood or tissue per local assessment, ECOG performance status of 0-1, disease that is refractory or not adequately responding to standard therapy, has no available standard therapy, or patient is intolerant of, or declined standard therapy (including pan-FGFRi), and measurable or evaluable disease per RECIST 1.1. FGFR2 alteration will be confirmed retrospectively by central laboratory assessment. Part 1 dose escalation employed the Bayesian Optimal Interval (BOIN) design to determine the MTD/RP2D of RLY-4008. Part 2 dose expansion is presently enrolling patients at the RP2D of RLY-4008 and includes 5 cohorts comprised of patients with: 1. FGFR2 fusion+ cholangiocarcinoma previously treated with an FGFRi; 2. FGFR2 fusion+ cholangiocarcinoma not previously treated with an FGFRi; 3. FGFR2 fusion+ solid tumors; 4. FGFR2 mutation+ solid tumors and 5. FGFR2 amplified solid tumors. Solid tumors in cohorts 3, 4 and 5 will have a focus in breast cancer. The primary endpoint is objective response rate (ORR); key secondary endpoints include: duration of response, safety and tolerability, correlation of FGFR2 genotype by central tissue assessment with antitumor response, characterization of PK profile, and quality of life. US enrollment began September 2020 and has expanded into Europe and Asia. Clinical trial information: NCT04526106. Citation Format: Suneel Kamath, David Tai, Irene Moreno, Hani Babiker, Zhaohui Jin, Changhoon Yoo, Fabien Ricard, Kai Yu Jen, Jim Coward, Jia Liu, Frans Opdam, Michael Millward, Mariano Ponz-Sarvise, Jeffrey Yachnin, Richard Kim, Joon Oh Park, Vivek Subbiah, Alison M. Schram. ReFocus: A Phase 1/2 Study of the Highly Selective FGFR2 Inhibitor, RLY-4008, in Patients with Advanced Solid Tumors Including Breast Cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT3-24-01.

Despite recent progress in the identification of mediators of podocyte injury, mechanisms underlying podocyte loss remain poorly understood, and cell-specific therapy is lacking. We previously reported that kidney and brain expressed protein (KIBRA), encoded by WWC1 , promotes podocyte injury in vitro through activation of the Hippo signaling pathway. KIBRA expression is increased in the glomeruli of patients with focal segmental glomerulosclerosis, and KIBRA depletion in vivo is protective against acute podocyte injury. Here, we tested the consequences of transgenic podocyte-specific WWC1 expression in immortalized human podocytes and in mice, and we explored the association between glomerular WWC1 expression and glomerular disease progression. We found that KIBRA overexpression in immortalized human podocytes promoted cytoplasmic localization of Yes-associated protein (YAP), induced actin cytoskeletal reorganization, and altered focal adhesion expression and morphology. WWC1 -transgenic (KIBRA-overexpressing) mice were more susceptible to acute and chronic glomerular injury, with evidence of YAP inhibition in vivo. Of clinical relevance, glomerular WWC1 expression negatively correlated with renal survival among patients with primary glomerular diseases. These findings highlight the importance of KIBRA/YAP signaling to the regulation of podocyte structural integrity and identify KIBRA-mediated injury as a potential target for podocyte-specific therapy in glomerular disease.

Abstract Background Mendelian randomization (MR) studies are susceptible to metadata errors (e.g. incorrect specification of the effect allele column) and other analytical issues that can introduce substantial bias into analyses. We developed a quality control (QC) pipeline for the Fatty Acids in Cancer Mendelian Randomization Collaboration (FAMRC) that can be used to identify and correct for such errors. Methods We collated summary association statistics from fatty acid and cancer genome-wide association studies (GWAS) and subjected the collated data to a comprehensive QC pipeline. We identified metadata errors through comparison of study-specific statistics to external reference data sets (the National Human Genome Research Institute-European Bioinformatics Institute GWAS catalogue and 1000 genome super populations) and other analytical issues through comparison of reported to expected genetic effect sizes. Comparisons were based on three sets of genetic variants: (i) GWAS hits for fatty acids, (ii) GWAS hits for cancer and (iii) a 1000 genomes reference set. Results We collated summary data from 6 fatty acid and 54 cancer GWAS. Metadata errors and analytical issues with the potential to introduce substantial bias were identified in seven studies (11.6%). After resolving metadata errors and analytical issues, we created a data set of 219 842 genetic associations with 90 cancer types, generated in analyses of 566 665 cancer cases and 1 622 374 controls. Conclusions In this large MR collaboration, 11.6% of included studies were affected by a substantial metadata error or analytical issue. By increasing the integrity of collated summary data prior to their analysis, our protocol can be used to increase the reliability of downstream MR analyses. Our pipeline is available to other researchers via the CheckSumStats package (https://github.com/MRCIEU/CheckSumStats).

139 Background: The fibroblast growth factor receptor (FGFR) pathway plays a key role in cellular proliferation, migration, survival and angiogenesis. Aberrant signaling through FGFR in colorectal cancer and other malignancies results from gene amplification or mutation, chromosomal translocation or ligand-dependent activation of the receptors. Pemigatinib is an oral inhibitor of FGFR1-3 with proven efficacy in FGFR-altered cholangiocarcinoma and myeloid/lymphoid neoplasms, among others. We hypothesized that pemigatinib would improve response rates compared to historical controls in patients with refractory FGF/FGFR-altered mCRC. Methods: ACCRU-GI-1701 was a multicenter, single-arm, Simon’s two-stage phase II clinical trial (NCT04096417) of the FGFR inhibitor pemigatinib in patients (pts) with FGF/FGFR-altered mCRC. Eligible pts had received prior fluoropyrimidine, oxaliplatin, irinotecan, and anti-VEGF/anti-EGFR/anti-PD-1 if eligible. Pts received pemigatinib 13.5 mg once daily on d1-21 of each cycle, with option to escalate to 18 mg in c2 if well tolerated. The primary endpoint was (unconfirmed) objective response (OR). A sample size of 21 evaluable pts would provide 82% power to detect a true OR rate of 20% or greater compared to a historical control of 5 % with a one-sided type I error rate of 0.1. A prespecified interim analysis for futility was planned after 12 evaluable patients. Results: A total of 14 patients were enrolled in the first stage of the study, and all were evaluable for the primary endpoint. No OR were observed (out of 12) crossing the futility boundary and resulting in permanent closure of the study. Among all enrolled patients, median age was 60.5 years, 71.4% were male, 92.9% Caucasian, 42.9% with no prior exposure to TAS-102 or regorafenib, and 64.3% with left-sided primary tumors. Treated patients all had tumors with FGFR1-4 mutations and/or FGF/FGFR amplifications by tissue- and/or blood-based molecular testing; no FGFR translocations were present. OR rate for this study was 0% (95% CI, 0-23.2%), with one patient achieving stable disease as best response. Median progression-free survival was 9.1 weeks (95% CI, 7.9-not evaluable [NE]), and median overall survival was 7.9 months (95% CI, 3.4-NE). Grade 3+ adverse events (AE) were seen in 42.9% of treated patients (including 1 grade 5 AE). Most commonly occurring AEs of any grade were anemia, hyperphosphatemia, alkaline phosphatase increased, aspartate aminotransferase increase, and fatigue. Conclusions: Pemigatinib demonstrated evidence of safety but not clinical activity in this population of patients with FGF/FGFR-altered mCRC. It is unknown whether pemigatinib would be active in mCRC patients with FGFR translocations/fusions as these were not represented in our trial. Translational studies are planned to investigate mechanisms of resistance to this therapy. Clinical trial information: NCT04096417 .

Abstract Retinoblastoma (RB) protein can exert tumor suppressor functions even when it becomes phosphorylated. It is thus essential to understand how phosphorylated RB (p-RB) expression and function are regulated. Here, we demonstrated that RING finger domain protein TRIM28 bound and promoted ubiquitination and degradation of CDK4/6-phosphorylated RB protein. SETDB1, a known TRIM28 binding partner, protected p-RB from degradation through the binding of methylated RB by its Tudor domain independent of its methyltransferase activity. SETDB1 was found to be frequently overexpressed due to gene amplification and positively correlated with p-RB in prostate cancer patient specimens. Inhibition of SETDB1 expression using a gene-specific antisense oligonucleotide (ASO) reduced tumor growth but accelerated RB protein degradation, limiting the therapeutic efficacy. However, coadministration of the CDK4/6 inhibitor palbociclib blocked ASO-induced RB degradation and resulted in a much greater cancer-inhibitory effect than each inhibitor alone both in vitro and in vivo. This study identified CDK4/6-dependent, TRIM28-mediated proteasomal degradation as a mechanism of RB inactivation and reveals SETDB1 as a key inhibitor of this process. Our findings suggest that combined targeting of SETDB1 and CDK4/6 represents a viable approach for the treatment of cancers with SETDB1 gene amplification or overexpression. Significance: The identification of a role for TRIM28 and SETDB1 in regulating CDK4/6-phosphorylated RB stability uncovers a combination strategy using CDK4/6 and SETDB1 inhibition to decrease RB degradation and inhibit cancer growth.

Abstract Background: Smoking is the most common etiology for lung cancer and smoking cessation does not eliminate the risk. An emerging area of interest for risk reduction is immunoprevention. MUC1 glycoprotein is aberrantly expressed in adenocarcinomas, including lung cancer and their premalignant lesions. MUC1 vaccine in the premalignant or high-risk setting may be effective in halting neoplastic development and progression. Trial design: Through the NCI-funded Cancer Prevention Network (CPN), we conducted a two-center pilot trial to evaluate immunogenicity of the MUC1 vaccine (assessed at 12 weeks), and safety (assessed at up to 24 weeks) in current and former heavy smokers. 87 participants were screened in order to have at least 40 evaluable for baseline and 12-week immunogenicity assessments. Smoking history of ≥30 pack-years and either current (still smoking or quit &lt; 1 year prior to pre-registration) or former smoker (quit 1-15 years prior to pre-registration); ages 55-80 years; ECOG performance status ≤1; CT scan of the chest done ≤ 6 months prior to pre-registration showing either negative findings (no nodules) or solid or part-solid nodules &lt; 6 mm in size (consistent with &lt; 1% probability of malignancy, Lung-RADs Version 1.0). Exclusion criteria were standard for lung cancer screening. Methods: MUC1 peptide plus polyICLC adjuvant (Hiltonol) vaccine was given at week 0, 2 and 10. Blood was collected for safety tests and immune assays pre and 2 weeks post each vaccine, and at week 24. Anti-MUC1 IgG titer was evaluated by ELISA. Based on previous studies of this vaccine, 40 evaluable participants would provide 96% power to detect immune response rate of 15% versus 40%, using a 2-sided test of proportions with type I error rate of 0.05. PBMC were assayed for the presence of regulatory T cells (Treg) and myeloid derived suppressor cells (MDSC) (secondary endpoint). Circulating levels of inflammatory cytokines and hsCRP were evaluated using commercially available tests (exploratory endpoint). AEs and toxicities were monitored for up to 24 weeks from the first vaccine. Results: 87 individuals were screened and 50 registered. 45 completed the study, 26 current and 19 former smokers (time since last smoked: average 7.8 years; 11 months -13 years). The vaccine was well-tolerated with injection site reactions being the most common AE. Immune response to the vaccine was lower than expected, with 2 current and 2 former smokers developing anti-MUC1 IgG titers ≥2 fold higher at week 12 over baseline (10%). We found high circulating levels of MDSCs in PBMC of both current and former smokers and very low or no serum cytokines. Conclusions: A preventative vaccine trial was feasible in individuals at high risk for lung cancer. However, we discovered a high level of immune suppression, previously documented only in advanced lung cancer. Mitigating the development of lung cancer in heavy smokers through vaccine administration may be limited by related immunosuppression. Citation Format: Olivera J. Finn, Julie Ward, Tami Krpata, Samantha Fatis, John McKolanis, Jia Xue, Pamela Beatty, Camille Jacqueline, Sharon Kaufman, Colleen Akerley, April Felt, Karrie Fursa, Anne Holland, Liz S. Ambulay, Nathan Foster, Ryan McMurray, Carrie Strand, Andres M. Salazar, Lisa Bengtson, Eva Szabo, Paul Limburg, Malgorzata Wojtowicz, David E. Midthun, Arjun Pennathur. A pilot study of a MUC1 vaccine in current and former smokers at high risk for lung cancer. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr PR002.