Citations

Abstract Background: In early stage, ERα-positive breast cancer, the concurrent use of endocrine therapy and chemotherapy has not been shown to be superior to sequential use. We hypothesized that genetic biomarkers can aid in selecting patients who would benefit from chemo-endocrine therapy. Our previous genome-wide association study (GWAS) and functional studies revealed that a single nucleotide polymorphism (SNP) in ZNF423, rs9940645, determines tamoxifen response. Specifically, 4-hydroxytamoxifen (4-OH-TAM) increases the gene expression of ZNF423, a transcription factor for BRCA1, in cells that are carry the rs9940645 variant, but not the wildtype, genotype. In this study, we set out to identify additional genes regulated by ZNF423, which, upon identifying a relationship between ZNF423 and cell cycle genes, led us to investigate taxane response in a SNP- and tamoxifen-dependent fashion. Method: Gene correlation analysis using The Cancer Genome Atlas (TCGA) breast cancer dataset was used to identify genes with expression correlated with that of ZNF423. Quantitative reverse transcription PCR, chromatin immunoprecipitation, and luciferase reporter assays were used to validate the gene associations. To test ZNF423 rs9940645-specific phenotypes, we used ZR75-1 cells, which are homozygous for the variant SNP, and ZR75-1 cells that were generated to be homozygous wild type (WT) using CRISPR-Cas9 technology, in addition to Hs578T breast cells with ERα overexpression (WT) and HCC1500 cells (variant). Cell cycle was assessed by propidium iodide staining. Cytotoxicity was assessed using a colorimetric assay. Results: Mitosis-related genes VRK1 and PBK, which encode histone H3 kinases, were experimentally validated to be regulated by ZNF423. Specifically, ZNF423 knockdown resulted in decreased VRK1 and PBK expression and activity. Additionally, ZNF423 knockdown resulted in enhanced docetaxel-induced G2/M arrest and cytotoxicity which could be rescued by VRK1 or PBK overexpression. Lastly, breast cancer cells carrying the rs9940645 variant SNP genotype had increased G2-M arrest and decreased cell viability when treated with docetaxel in combination with estradiol and 4-OH-TAM. Conclusion: We identified ZNF423regulated genes involved in the G2/M phase of the cell cycle. We found that 4-OH-TAM sensitized ERα-positive breast cancer cells to docetaxel treatment in a ZNF423 SNP-dependent manner. Our findings suggest that patients with rs9940645 variant genotype may benefit from concurrent tamoxifen endocrine therapy and docetaxel chemotherapy. This would impact a substantial proportion of patients given the minor allele frequency of 0.47 for this SNP. Citation Format: Gen Wang, Sisi QIN, Jacqueline Zayas, James N. Ingle, Mohan Liu, Richard Weinshilboum, Kunwei Shen, Liewei Wang. 4-Hydroxytamoxifen enhances sensitivity of estrogen receptor α-positive breast cancer to docetaxel in an estrogen and ZNF423 SNP-dependent fashion [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 2940.

Background: Oncologic sternectomy results in complex defects where preoperative planning is paramount to achieve best reconstructive outcomes. Although pectoralis major muscle flap (PMF) is the workhorse for sternal soft tissue coverage, additional flaps can be required. Our purpose is to evaluate defects in which other flaps beside PMF were required to achieve optimal reconstruction. Methods: A retrospective review of consecutive patients at our institution who underwent reconstruction after sternal tumor resection was performed. Demographics, surgical characteristics, and outcomes were evaluated. Further analysis was performed to identify defect characteristics where additional flaps to PMF were needed to complete reconstruction. Results: In 11 years, 60 consecutive patients were identified. Mean age was 58 (28–81) years old, with a mean follow-up of 40.6 (12–64) months. The majority were primary sternal tumors (67%) and the mean defect size was 148 cm2 (±81). Fourteen (23%) patients presented with postoperative complications, and the 30-day mortality rate was 1.6%. In 19 (32%) cases, additional flaps were required; the most common being the rectus abdominis muscle flaps. Larger thoracic defects (P = 0.011) and resections involving the inferior sternum (P = 0.021) or the skin (P = 0.011) were more likely to require additional flaps. Conclusions: Reconstruction of oncologic sternal defects requires a multidisciplinary team approach. Larger thoracic defects, particularly those that involve the skin and the inferior sternum, are more likely to require additional flaps for optimal reconstruction.

AbstractBackground and objectivesMacroreentrant atrial tachycardias often occur following atrial fibrillation ablation, most commonly due to nontransmural lesions in prior ablation lines. Perimitral atrial flutter is one such arrhythmia which requires ablation of the mitral isthmus. Our objectives were to review the literature regarding ablation of the mitral isthmus and to provide our approach for assessment of mitral isthmus block.MethodsWe review anatomical considerations, ablation strategies, and assessment of conduction block across the mitral isthmus, which is subject to several pitfalls. Activation sequence and spatial differential pacing techniques are discussed for assessment of both endocardial and epicardial bidirectional mitral isthmus block.ResultsTraditional methods for verifying mitral isthmus block include spatial differential pacing, activation mapping, and identification of double potentials. Up to 70% of cases require additional ablation in the coronary sinus (CS) to achieve transmural block. Interpretation of transmural block is subject to six pitfalls involving pacing output, differentiation of endocardial left atrial recordings from epicardial CS recordings, identification of a slowly conducting gap in the line, and catheter positioning during spatial differential pacing. Interpretation of unipolar electrograms can identify nontransmural lesions. We employ a combined epicardial and endocardial assessment of mitral isthmus block, which involves using a CS catheter for epicardial recording and a duodecapolar Halo catheter positioned around the mitral annulus for endocardial recording.ConclusionsThe assessment of transmural mitral isthmus block can be challenging. Placement of an endocardial mapping catheter around the mitral annulus can provide a precise assessment of conduction across the mitral isthmus.

Abstract The presence of FMS-like receptor tyrosine kinase-3 internal tandem duplication (FLT3-ITD) mutations in patients with acute myeloid leukemia (AML) is associated with poor clinical outcome. FLT3 tyrosine kinase inhibitors (TKIs), although effective in kinase ablation, do not eliminate primitive FLT3-ITD+ leukemia cells, which are potential sources of relapse. Thus, understanding the mechanisms underlying FLT3-ITD+ AML cell persistence is essential to devise future AML therapies. Here, we show that expression of protein arginine methyltransferase 1 (PRMT1), the primary type I arginine methyltransferase, is increased significantly in AML cells relative to normal hematopoietic cells. Genome-wide analysis, coimmunoprecipitation assay, and PRMT1-knockout mouse studies indicate that PRMT1 preferentially cooperates with FLT3-ITD, contributing to AML maintenance. Genetic or pharmacological inhibition of PRMT1 markedly blocked FLT3-ITD+ AML cell maintenance. Mechanistically, PRMT1 catalyzed FLT3-ITD protein methylation at arginine 972/973, and PRMT1 promoted leukemia cell growth in an FLT3 methylation–dependent manner. Moreover, the effects of FLT3-ITD methylation in AML cells were partially due to cross talk with FLT3-ITD phosphorylation at tyrosine 969. Importantly, FLT3 methylation persisted in FLT3-ITD+ AML cells following kinase inhibition, indicating that methylation occurs independently of kinase activity. Finally, in patient-derived xenograft and murine AML models, combined administration of AC220 with a type I PRMT inhibitor (MS023) enhanced elimination of FLT3-ITD+ AML cells relative to AC220 treatment alone. Our study demonstrates that PRMT1-mediated FLT3 methylation promotes AML maintenance and suggests that combining PRMT1 inhibition with FLT3 TKI treatment could be a promising approach to eliminate FLT3-ITD+ AML cells.

Background:Autoimmune haemolytic anaemia (AIHA) is characterized by haemolysis mediated by autoantibodies directed against red blood cells (RBCs). Warm antibody (wAIHA; 60%>70%) and cold agglutinin disease (CAD; 20%>25%) subclasses are defined by the immunoglobulin (Ig) isotype involved and its thermal optimum for binding RBCs. wAIHA is mediated by IgG while 90% of CAD is mediated by IgM isotypes. CAD and wAIHA outcomes can be life‐threatening, but no therapies are approved. Complement C3b deposition on RBCs plays a central role in AIHA, accelerating phagocytosis in the liver and/or spleen (extravascular haemolysis) and forming membrane attack complexes (intravascular haemolysis). By blocking formation of C3b, APL‐2, a cyclic peptide, has potential as a novel therapeutic for AIHA.Aims:To assess whether inhibiting complement C3 with daily subcutaneous (SC) doses of APL‐2 (270 mg/day or 360 mg/day) prevents intra‐ and extravascular haemolysis in AIHA subjects, reducing anaemia associated signs and symptoms.Methods:Subjects with primary AIHA were eligible for this Ph 2 open‐label study to assess the safety, tolerability, efficacy, and pharmacokinetics of APL‐2. Subjects had haemoglobin (Hb) levels < 11 g/dL, signs of haemolysis, and a positive direct agglutinin test (DAT) for IgG and/or complement C3. Twenty‐four subjects (13 CAD, 11 wAIHA) were recruited and will be treated with APL‐2 for 48 weeks. Efficacy was assessed by change from baseline in Hb, transfusion requirements, absolute reticulocyte counts (ARC), lactate dehydrogenase (LDH), haptoglobin, indirect bilirubin (INDBIL), and Functional Assessment of Illness Therapy (FACIT) fatigue score. Data are reported after 16 weeks (Day 112).Results:Two of 13 CAD subjects withdrew; 7 of 11 remaining subjects reached Day 112. Mean Hb (standard error [SE]) increased from 8.9 (0.4) [n = 13] to 11.6 (0.5) [n = 7] g/dL, and mean LDH, ARC, and INDBIL returned within normal range. Mean FACIT scores (SE) increased 9.9 (3.4) points from baseline. Two subjects had pre‐study and 1 had on‐study transfusions (normalized to 112 days). All 13 CAD experienced ≥1 treatment‐emergent adverse event (TEAE), mainly Grade 1–2 and unrelated. Four subjects reported 10 unrelated serious adverse events (SAEs) (6 SAEs in 1 subject). Three subjects experienced 3 unrelated Grade 3 TEAEs (pneumonia, dyspnoea, hypertension); 1 subject reported 2 unrelated Grade 4 TEAEs (high calcium, high creatinine) and withdrew.Eight of 11 wAIHA subjects were DATmonoC3+ and 3 were DATmonoC3‐. Two of 3 DATmonoC3‐ withdrew for lack of response and efficacy data are reported for 8 DATmonoC3+ subjects. Six of these reached Day 112. Mean Hb (SE) increased from 9.2 (0.3) [n = 8] to 10.8 (0.5) [n = 6] g/dL, and mean ARC and INDBIL returned within normal. Mean FACIT scores (SE) increased 2.7 (2.8) points from baseline. One subject had pre‐study and 2 had on‐study transfusions (normalized to 112 days). Ten of 11 wAIHA (C3+ and C3‐) experienced ≥1 TEAE, mainly Grade 1–2 and unrelated. Five subjects reported 8 unrelated SAEs. Five subjects experienced 13 unrelated Grade 3 TEAEs (oral squamous cell carcinoma, haemolytic flare, purpura, acute kidney injury, dyspnoea, chest pain); 1 subject reported 1 unrelated Grade 4 TEAE (haemolytic flare) and withdrew. Six‐month data for 10 CAD and 6 wAIHA C3+ is planned for June 2019.Summary/Conclusion:APL‐2 increases Hb values in CAD and wAIHA C3+ within the first weeks of treatment with sustained benefit with longer exposure. APL‐2 reduces intra‐ and extravascular haemolysis shown by reductions in LDH, INDBIL, and ARC. APL‐2 appears to be safe and well‐tolerated.

Background and objectives To evaluate the growth pattern of kidney cyst number and cyst volume in association with kidney size, demographics, and genotypes in autosomal dominant polycystic kidney disease. Design, setting, participants, & measurements Kidney cyst number and cyst volume were measured from serial magnetic resonance images, giving a maximum follow-up of 14.23 years, from 241 patients with autosomal dominant polycystic kidney disease (15–46 years old at baseline). The growth pattern was analyzed, in association with sex, age, height-adjusted total kidney volume, and genotype, using linear mixed models of repeated measurements and tests of interactions with age (as a time-dependent covariate) to assess rates of change over time. Models were also fit using Irazabal class. Genotypic groups were characterized as either ( 1 ) PKD1 truncating, PKD1 nontruncating, and PKD2 plus patients with no mutation detected; or ( 2 ) in combination with PKD1 mutation strength groups. Results Imaging and genetic data were collected (at least one visit) for 236 participants. The mean height-adjusted total cyst number increased exponentially over time from a baseline value of 762 to 1715 at the last clinic visit, while the mean height-adjusted total cyst volume increased exponentially from 305 to 770 ml. Height-adjusted total kidney volume, height-adjusted total cyst number, and height-adjusted total cyst volume were all highly correlated over time. Female participants and participants with larger height-adjusted total kidney volume at baseline showed smaller rates of change in the log of height-adjusted total cyst number and cyst volume. PKD1 was associated with significant increases in both cyst number and volume at a given age, but genotype did not significantly affect the rate of growth. Conclusions Both height-adjusted total cyst number and height-adjusted total cyst volume increased exponentially and more than doubled over 14.23 years of follow-up. Compared with PKD2 plus no mutation detected, PKD1 was associated with a greater cyst number and volume at a given age, but no significant difference in the rate of growth.

Abstract Background Vedolizumab effectiveness estimates immediately after Food and Drug Administration (FDA) approval for ulcerative colitis (UC) and Crohn’s disease (CD) are limited by use in refractory populations. We aimed to compare treatment patterns and outcomes of vedolizumab in 2 time frames after FDA approval. Methods We used 2 data sets for time trend analysis, an academic multicenter vedolizumab consortium (VICTORY) and the Truven MarketScan database, and 2 time periods, May 2014–June 2015 (Era 1) and July 2015–June 2017 (Era 2). VICTORY cumulative 12-month clinical remission, corticosteroid-free remission, and mucosal healing rates, and Truven 12-month hospitalization and surgery rates, were compared between Eras 1 and 2 using time-to-event analyses. Results A total of 3661 vedolizumab-treated patients were included (n = 1087 VICTORY, n = 2574 Truven). In both cohorts, CD and UC patients treated during Era 2 were more likely to be biologic naïve. Compared with Era 1, Era 2 CD patients in the VICTORY consortium had higher rates of clinical remission (31% vs 40%, P = 0.03) and mucosal healing (42% vs 58%, P < 0.01). These trends were not observed for UC. In the Truven database, UC patients treated during Era 2 had lower rates of inflammatory bowel disease–related hospitalization (22.4% vs 9.6%, P < 0.001) and surgery (17.2% vs 9.4%, P = 0.008), which was not observed for CD. Conclusion Since FDA approval, remission and mucosal healing rates have increased for vedolizumab-treated CD patients, and vedolizumab-treated UC patients have had fewer hospitalizations and surgeries. This is likely due to differences between patient populations treated immediately after drug approval and those treated later.