Citations

Abstract Background: Constitutive MEK-ERK activation induced by BRAFV600E or RAS mutation promotes tumor metastasis in CRC that is mediated by transcription factors regulating epithelial-to-mesenchymal transition (EMT). We determined the role of ZEB1, an EMT master transcription factor, and its potential regulation by the ubiquitin specific peptidase 10 (USP10), in tumor metastasis mediated by MEK-ERK. Materials and Methods: Isogenic RKO [BRAFV600E or wild-type (wt)] and Colo320 (BRAF/KRAS wt/wt) human CRC cells were utilized. Colo320 cells were transfected with mutant KRASG12D. In addition to parental cells, we generated USP10 shRNA expressing RKO and Colo320 cells. Cells were treated with the MEK1/2 inhibitor cobimetinib or BRAF inhibitor encorafenib. Cell migration was analyzed by wound healing and transwell assays. Protein/protein interaction was analyzed by immunoprecipitation. Protein ubiquitination level was determined by ubiquitination assay. In an orthotopic model, lung metastases in mice were generated by tail vein injection of RKO cells. Results: We demonstrate MEK-ERK activation, induced by BRAFV600E, promotes CRC metastasis through inhibition of the USP10-ZEB1 axis. USP10 is shown to interact with ZEB1 and to remove its K27 linkage ubiquitination chain, thus increasing K48 ubiquitination of ZEB1 protein that results in proteosome-mediated degradation of ZEB1. MEK-ERK induced the phosphorylation of USP10 that is shown to attenuate the USP10-ZEB1 interaction and results in ZEB1 stabilization in RKO and Colo320 cell lines. Increased ZEB1 expression promotes tumor cell migration in vitro and metastasis in a murine xenograft model that could be suppressed by cobimetinib or BRAFV600E-directed therapy with encorafenib and cetuximab. Conclusions: Targeting RAF/RAS-driven MEK/ERK signaling can suppress ZEB1 stabilization to inhibit tumor metastasis. Suppression of metastasis occurs by a novel mechanism of ZEB1 stabilization that is regulated by an atypical USP10 deubiquitinase activity. Citation Format: Bo Qin, Lei Sun, Frank A. Sinicrope. MEK/ERK induces the EMT transcription factor ZEB1 that is regulated by USP10 and promotes colorectal cancer metastasis that can be inhibited by BRAFV600E-directed therapy [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 953.

Abstract Zinc finger E-box binding homeobox 1 (ZEB1) is a transcription factor regulating epithelial to mesenchymal transition (EMT). To date, regulation of ZEB1 by key signaling pathways including RAS/RAF/MEK/ERK remains unclear, and few studies have focused on molecular associations or functional alterations of ZEB1 by post-translational modification. Here, we report an interaction of ZEB1 with the deubiquitinase USP10 that is regulated by MEK-ERK signaling. USP10 removes the K27 linkage ubiquitination chain on ZEB1 that enhances K48 polyubiquitination and promotes ZEB1 proteasomal degradation. However, constitutive activation of ERK can phosphorylate USP10 at Ser236 to impair its interaction with ZEB1 and, thereby, stabilize ZEB1 protein shown to promote colorectal cancer metastasis in mice. Conversely, inhibition of MEK-ERK blocks USP10 phosphorylation to enhance the USP10-ZEB1 interaction which can suppress ZEB1-mediated tumor cell migration and metastasis in vivo. Together, these data demonstrate a novel function of USP10 in the regulation of ZEB1 ubiquitination and protein stability that can inhibit ZEB1-mediated tumor metastasis.

Abstract B-cell chronic lymphocytic leukemia (B-CLL) is the most common leukemia in adults with CD19-targeting CAR T-cell therapy showing an excellent initial curative response. However, 10-20% of patients who receive anti-C19 CAR T-cell treatment experience relapse due to CD19 antigen loss. B-cell activating factor receptor (BAFF-R) that is expressed on the surface of normal and neoplastic B cells mediates the survival of mature peripheral B cells along with the B-cell receptor. Since B-CLL is characterized by apoptotic disruption and subsequent accumulation of mature B cells, BAFF-R is a logical, novel target for CAR T-cell therapy directed against B-CLL, especially if CD19 antigen loss occurs. In this study, we first manufactured BAFF-R CAR T-cells by infecting healthy donor Tnaïve/memory (Tn/mem) cells with BAFF-R CAR lentivirus before evaluating the antitumor activity of BAFF-R CAR T-cells on wild type MEC-1 (a B-CLL cell line), modified MEC-1, and primary cell lines. Antigen-specific cytotoxicity and activation of the BAFF-R CAR T-cells or control CD19 CAR T-cells were determined upon incubation with B-CLL cell lines and patient-derived primary B-CLL by measuring degranulation and IFN-γ release, respectively. BAFF-R CAR T-cells demonstrated substantial cytotoxicity against MEC-1, CD19-deficient MEC-1, and primary B-CLL cell lines; CD19 CAR T-cells showed no effect on CD19-deficient MEC-1 cells but did show effects with primary B-CLL and MEC-1 cells. Similarly, the release of IFN-γ was greater when BAFF-R CAR T-cells were co-cultured with CD19-deficient MEC-1 or primary B-CLL compared to CD19 CAR T-cells co-cultured with CD19-deficient MEC-1. In summary, BAFF-R CAR T-cells exert significant antitumor properties not only on patient-derived primary B-CLL cells but also on a CD19-deficient B-CLL cell line. We, therefore, assert BAFF-R-targeting CAR T-cells to be a novel therapeutic avenue for patients newly diagnosed with B-CLL and patients experiencing relapsed B-CLL after anti-CD19 therapy. Citation Format: Yan Luo, Kaihin Lui, Tommy T. To, Andrew liu, Farah Yassine, Mohamed A. Kharfan Dabaja, Martha E. Gadd, Hong Qin. Antitumor activity of BAFF-R targeting CAR T-cells on chronic lymphocytic leukemia [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 2855.

7015 Background: Ruxolitinib (RUX), a Janus kinase (JAK) 1/2 inhibitor, is the current standard of care for patients (pts) with myelofibrosis (MF) that improves splenomegaly and disease symptoms with limited impact on disease biology. Many pts lose response over time, highlighting an unmet need for novel therapies. Navitoclax (NAV) is an oral, small-molecule inhibitor of BCL-XL and BCL-2 that has a synergistic effect when used in combination with JAK inhibitors to enhance apoptosis. This ongoing, open-label, multicenter, phase 2 trial (NCT03222609) is evaluating the efficacy and safety of NAV with/without RUX in pts with MF. Here, we report results from JAK inhibitor-naïve pts treated with NAV+RUX. Methods: Enrolled pts had primary or secondary MF with splenomegaly (DIPSS ≥INT-1) and did not receive prior JAK-2 therapy or bromodomain and extraterminal motif (BET) inhibitors. Pts initiated NAV at 100 mg QD or 200 mg QD if baseline (BL) platelet count was ≤150 × 109/L or >150 × 109/L, respectively. RUX was given BID with starting dose based on BL platelet count per local label. The primary endpoint was spleen volume reduction of ≥35% (SVR35) from BL at wk 24. Key secondary endpoints were ≥50% reduction in total symptom score (TSS50), bone marrow (BM) fibrosis reduction, and anemia response. Adverse events (AEs) were monitored throughout the study. Results: As of Oct 04, 2021, 32 pts received NAV+RUX. Median duration of f/u was 6.1 (range, 1.9 ─ 18.6) mos. 28 (88%) pts received NAV 200 mg and 4 (13%) received 100 mg OD. Median age was 69 (44 ─ 83) yrs, and median spleen volume was 1889.08 cm3 (645.6 ─ 7339.6). Median NAV and RUX exposures were 24.1 (5.1 ─ 80.9) and 20.1 (0.1 ─ 80.1) wks, respectively. 31 (97%) pts reported ≥1 AE (Grade ≥3 AEs, 25 [78%]; serious AEs, 6 [19%]). Most common Grade ≥3 AEs were anemia (34%), thrombocytopenia (31%), and neutropenia (19%). 3 (9%) and 2 (6%) pts reported an AE leading to NAV and RUX discontinuation, respectively, and 2 (6%; 1 PD, 1 cardiac disorder unrelated to NAV) AEs led to death ≤30 days after last NAV dose. SVR35 was achieved by 52% of evaluable pts at wk 24 (SVR35 in INT-2, 50%; HR, 33%) and by 76% at any time on treatment (Table). Median time to first SVR35 was 12.1 (11 ─ 47) wks. Conclusions: The combination of NAV+RUX was well tolerated and demonstrated early and robust reductions in spleen volume, anemia, and BM fibrosis in pts without prior JAK-2 inhibitor exposure. SVR35, TSS50, and BM fibrosis improved over time. Clinical trial information: NCT03222609. [Table: see text]

Abstract Although costimulatory molecules have been shown to boost antitumor immune responses, their significance in stomach adenocarcinoma (STAD) is unknown. The purpose of this study was to examine the gene expression patterns of costimulatory molecule genes in STAD and to develop a predictive signature to aid in therapy selection and outcome prediction. We used 60 costimulatory family genes from prior research to conduct the first complete costimulatory molecule analysis in STAD patients. For the two groups discovered, consensus clustering analysis based on these 60 genes indicated unique distribution patterns and prognostic differences. Then, using Lasso and Cox regression analysis, 9 costimulatory molecular gene pairs (CMGPs) of prognostic value were discovered. With these 9 CMGPs, we were able to develop a costimulatory molecule-related prognostic signature, which performed well in an external dataset. For STAD patients, the signature was proved to be a risk factor independent of clinical characteristics, indicating that this may be employed in conjunction with clinical considerations. An further connection between the signature and immunotherapy response was discovered. People who had high mutation rates, an abundance of infiltrating immune cells, and an immunosuppressive milieu were classed as high-risk. It is possible that patients classed as high-risk have a better prognosis for immunotherapy since these patients have greater cytolytic activity scores and immunophenoscores of CTLA4 and PD-L1/PD-L2 blocker As a consequence, clinicians might use our signature to better assess patient prognosis and develop treatment plans.

Genome-wide association studies (GWAS) have identified more than 200 susceptibility loci for breast cancer, but these variants explain less than a fifth of the disease risk. Although gene–environment interactions have been proposed to account for some of the remaining heritability, few studies have empirically assessed this. We obtained genotype and risk factor data from 46,060 cases and 47,929 controls of European ancestry from population-based studies within the Breast Cancer Association Consortium (BCAC). We built gene expression prediction models for 4,864 genes with a significant (P < 0.01) heritable component using the transcriptome and genotype data from the Genotype-Tissue Expression (GTEx) project. We leveraged predicted gene expression information to investigate the interactions between gene-centric genetic variation and 14 established risk factors in association with breast cancer risk, using a mixed-effects score test. After adjusting for number of tests using Bonferroni correction, no interaction remained statistically significant. The strongest interaction observed was between the predicted expression of the C13orf45 gene and age at first full-term pregnancy (PGXE = 4.44 × 10−6). In this transcriptome-informed genome-wide gene–environment interaction study of breast cancer, we found no strong support for the role of gene expression in modifying the associations between established risk factors and breast cancer risk. Our study suggests a limited role of gene–environment interactions in breast cancer risk.

Approximately one‐third of patients with metastatic castration‐resistant prostate cancer (CRPC) exhibited primary abiraterone resistance. To identify alternative treatment for abiraterone nonresponders, we performed drug discovery analyses using the L1000 database using differentially expressed genes identified in tumor biopsies and patient‐derived xenograft (PDX) tumors between abiraterone responders and nonresponders enrolled in PROMOTE trial. This approach identified 3 drugs, including topoisomerase II (TOP2) inhibitor mitoxantrone, CDK4/6 inhibitor palbociclib, and pan‐CDK inhibitor PHA‐793887. These drugs significantly suppressed the growth of abiraterone‐resistant cell lines and PDX models. Moreover, we identified 11 genes targeted by all 3 drugs that were associated with worse outcomes in both the PROMOTE and Stand Up To Cancer cohorts. This 11‐gene panel might also function as biomarkers to select the 3 alternative therapies for this subgroup of patients with CRPC, warranting further clinical investigation.

ABSTRACT Background and Objective Patients with dementia with Lewy bodies (DLB) may have overlapping Alzheimer's disease pathology. We investigated the longitudinal rate of tau accumulation and its association with neurodegeneration and clinical disease progression in DLB. Methods Consecutive patients with probable DLB (n = 22) from the Mayo Clinic Alzheimer's Disease Research Center and age‐matched and sex‐matched cognitively unimpaired controls (CU; n = 22) with serial magnetic resonance imaging and flortaucipir positron emission tomography scans within an average of 1.6 years were included. Regional annualized rates of flortaucipir uptake standardized uptake value ratios (SUVr) were calculated. Regional annualized rates of cortical volume change were measured with the Tensor Based Morphometry–Syn algorithm. Results The annual increase of flortaucipir SUVr was greater in the middle and superior occipital, fusiform, and inferior parietal cortices in DLB (mean: 0.017, 0.019, 0.019, and 0.015, respectively) compared with the CU (mean: −0.006, −0.009, −0.003, and − 0.005, respectively; P < 0.05). In patients with DLB (but not the CU), a longitudinal increase in flortaucipir SUVr was associated with longitudinal cortical atrophy rates in the lateral occipital and inferior temporoparietal cortices, hippocampus, and the temporal pole as well as a concurrent decline on Mini‐Mental State Examination and Clinical Dementia Rating–Sum of Boxes in the lateral occipital and the fusiform cortices. Conclusions Tau accumulation was faster in DLB compared with the CU, with increased accumulation rates in the lateral occipital and temporoparietal cortices. These increased rates of tau accumulation were associated with neurodegeneration and faster disease progression in DLB. Tau may be a potential treatment target in a subset of patients with DLB. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society