Citations

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with dismal clinical outcomes. Conventional chemotherapies were previously shown to have some clinical efficacy, however, long-term outcomes of BPDCN patients remain poor. In a recent clinical trial, SL-401 demonstrated an overall response rate (ORR) of 90% in previously untreated BPDCN patients. Despite promising outcomes observed in SL-401 studies, there remains a lack of data regarding the optimal first-line therapy. In this single institution retrospective study, we explored the survival outcomes based on front-line treatment and allogeneic stem cell transplant (allo-SCT). A total of 49 patients with confirmed diagnosis of BPDCN were included in the study. Median age at diagnosis was 71.4 (32.0-91.4) years with a male predominance (82%). Among these, 11 (22%) patients had concurrent hematologic neoplasms at the time of BPDCN diagnosis. The most common site of disease involvement was skin (n=42, 86%) followed by bone marrow (BM) (n=32, 65%), lymph node (LN) (n=13, 27%), and nasopharynx (n=2, 4%) with 14 (29%) and 5 (10%) patients having skin and BM involvement only, respectively. Of note, 17 (35%) patients had both skin and BM disease and 8 (16%) had simultaneous skin, BM, and LN involvement. In the front-line setting, CHOP-based regimens, hyper-CVAD, and SL-401 were used in 10 (20%), 11 (22%), and 12 (24%) patients, respectively. The median cycle number of SL-401 treatment was 6 (1-73). Allo-SCT was performed in 10 (20%) patients and 4 (8%) patients received autologous stem cell transplant (auto-SCT). Transplant was performed following first-line therapy in 11 patients (CR, n=10; PR, n=1) and second-line therapy in 3 patients (CR, n=3). Among 21 vs. 12 patients who received chemotherapy vs. SL-401 as their first-line therapy, a total of 11 (52%) and 3 (25%) patients underwent transplant. A total of 23 (55%), 13 (31%), and 6 (14%) patients achieved a complete response (CR), partial response (PR), and progressive disease (PD), respectively. CR rate was higher in patients who were treated with hyper-CVAD compared to others, however, it was not statistically significant (50% in CHOP-based regimens vs. 91% in hyper-CVAD, P=0.064; 50% in SL-401 vs. 91% in hyper-CVAD, P=0.069). The median PFS was 9.9 months and the median OS was not reached when all patients were included for the analyses. In the subgroup analyses, patients who were treated with hyper-CVAD had longest PFS compared to patients treated with CHOP-based regimens (HR=0.217, 95%CI=0.050-0.933, P=0.003) or SL-401 (HR=0.385, 95%CI=0.126-1.179, P=0.075) although the PFS difference between hyper-CVAD and SL-401 did not reach the statistical significance. There was no PFS difference between SL-401 and CHOP-based regimen treated groups (HR=0.931, 95%CI=0.321-2.70, P=0.894). In the OS analysis based on first-line therapy, there was no difference between patients treated with SL-401 compared to patients treated with chemotherapy regimens (HR=1.597, 95%CI=0.460-5.548, P=0.431). Further, there was no OS difference between individual types of front-line therapies (P=0.678). In contrast, patients who received allo-SCT showed significantly longer OS outcomes compared to patients with no transplant (HR=0.160, 95%CI=0.0453-0.56, P=0.041). Additional OS analyses based on age (<60 vs. ≥60) (HR=0.481, 95%CI=0.146-1.582, P=0.258), ASXL1 mutation (HR=1.705, 95%CI=0.2773-10.48, P=0.5649), or presence of previous or concurrent hematologic malignancy (HR=2.97, 95%CI=0.65-13.57, P=0.1602) did not show any statistical difference. In a multivariate Cox model (adjusting for age, front-line therapy, gender, and transplant) allo-SCT was significant factor for OS (HR=0.137, 95%CI=0.020-0.959, P=0.045). In conclusion, our study supports current recommendations of using SL-401 or hyper-CVAD as the first-line treatments followed by consolidation with allo-SCT in the eligible responders to induction therapy to further improve survival outcomes in BPDCN patients. Disclosures Lancet: Abbvie: Consultancy; Agios Pharmaceuticals: Consultancy, Honoraria; Astellas Pharma: Consultancy; Celgene: Consultancy, Research Funding; Daiichi Sankyo: Consultancy; ElevateBio Management: Consultancy; Jazz Pharmaceuticals: Consultancy; Pfizer: Consultancy. kharfan-Dabaja:Daiichi Sankyo: Consultancy; Pharmacyclics: Consultancy. Sokol:Kyowa/Kirin Inc.: Membership on an entity's Board of Directors or advisory committees; EUSA Pharma: Consultancy, Honoraria, Speakers Bureau; Kymera Therapeutics: Membership on an entity's Board of Directors or advisory committees.

Nearly 20% of patients with myelofibrosis progress to blast phase disease; an aggressive form of acute myeloid leukemia. Although previous studies have implicated loss of TP53 or JARID2 in progression, by and large the genetic events that lead to conversion to blast phase remain unknown. To identify genes whose loss drives progression, we performed a focused CRISPR/Cas9 screen in which murine Jak2V617F bone marrow cells expressing Cas9 were transduced with two separate sgRNA libraries of known tumor suppressor genes and subjected to colony replating assays. Transduction of one of the two libraries led to serial replating and enhanced self-renewal of the Jak2V617F cells. Subsequent DNA sequencing revealed enrichment of all four guides targeting STK11, the gene that encodes LKB1 which regulates a number of key cellular pathways including energy utilization by activation of AMPK. To confirm that loss of Stk11 is the event that leads to increased clonogenicity, we collected cells from Jak2V617F/Vav-Cre+ and control Vav-Cre+ mice and induced Stk11 knockout by electroporating Cas9-Stk11 sgRNA ribonucleoprotein complexes. Consistent with the screening results, only Jak2V617F Vav-Cre+ cells with Cas9-Stk11 sgRNA showed serial replating. To determine whether Stk11 is required for growth of cells with a different driver of enhanced JAK/STAT signaling, we doubly transduced Stk11 homozygous floxed bone marrow cells with MPLW515L-mCherry and Cre-GFP to delete Stk11. As expected, cells with both MPLW515L and Cre recombinase showed enhanced self-renewal, while singly infected control cells failed to replate. These results demonstrate that activation of JAK/STAT signaling can overcome the requirement for Stk11 in normal hematopoiesis and suggest that STK11 loss may be a strong driver of malignant transformation in combination with enhanced JAK-STAT signaling. We next investigated the mechanism by which loss of STK11 cooperates with enhanced JAK/STAT signaling to promote leukemia. RNA-sequencing of wild-type, Stk11+/+/ MPLW515L, and Stk11-/-/MPLW515L hematopoietic cells revealed enrichment of a number of pathways related to hypoxia, oxidative phosphorylation and mitochondrial translation in cells lacking LKB1. Western blot assays confirmed activation of mTOR signaling as well as HIF1a stabilization and pathway activation, both of which have been reported to lie downstream of LKB1 loss. We also performed a number of studies to determine the relevance of reduced LKB1 expression to leukemic progression. First, we induced deletion of Stk11 in mice that were transplanted with HSPCs expressing MPLW515L after development of the MPN phenotype. Loss of Stk11 caused a rapid lethality that was associated with enhanced bone marrow fibrosis and osteosclerosis. We also observed accumulation of leukemic blasts in small clusters consistent with AML transformation arising in the spent phase MPN. Additionally, we deleted STK11 by CRISPR/Cas9 in primary MPN patient samples and monitored their engraftment in immunocompromised mice. We observed enhanced engraftment and increased reticulin fibrosis and osteosclerosis in mice that received the STK11 edited cells compared to those with non-targeted sgRNA. Third, we compared the expression of STK11 in paired blast and chronic phase myelofibrosis patient samples by RT-PCR. Consistent with the hypothesis that loss of STK11 facilitates leukemia, we found that its expression was decreased by more than 50% in five of seven paired post-MPN AML patient samples, with two having STK11 levels below 20%. We further validated downregulation of LKB1 by immunohistochemistry on paired chronic and blast phase MPN specimens and observed little staining in the blast phase specimens. Finally, to further show that the mechanism of in vitro enhanced self-renewal is related to leukemia progression, we stained the paired marrows for HIF1a and saw a dramatic increase in staining at the AML phase. We also analyzed RNA-seq data of paired chronic versus blast phase MPNs specimens and observed that there is a strong congruence of enriched pathways that are associated with the in vitro mouse HSPC phenotype and the human blast phase progression, such as oxidative phosphorylation and hypoxia. Together, our study demonstrates that loss of LKB1/STK11 promotes transformation of cells with activated JAK/STAT signaling and that STK11 is a prominent candidate tumor suppressor gene in post-MPN AML. Disclosures Gurbuxani: UpToDate: Honoraria. Hoffman:Dompe: Research Funding; Protagonist: Consultancy; Abbvie: Membership on an entity's Board of Directors or advisory committees; Forbius: Consultancy; Novartis: Membership on an entity's Board of Directors or advisory committees. Levine:Astellas: Consultancy; Amgen: Honoraria; Gilead: Honoraria; Qiagen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Morphosys: Consultancy; Novartis: Consultancy; Prelude Therapeutics: Research Funding; Loxo: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Imago: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Isoplexis: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Lilly: Consultancy, Honoraria; Janssen: Consultancy. Rampal:Galecto: Consultancy; Incyte: Consultancy, Research Funding; Constellation: Research Funding; Stemline: Consultancy, Research Funding; Celgene: Consultancy; Jazz Pharmaceuticals: Consultancy; CTI Biopharma: Consultancy; Abbvie: Consultancy; Pharmaessentia: Consultancy; Promedior: Consultancy; Blueprint: Consultancy.

Abstract The results from the RATIFY trial (ClinicalTrials.gov: NCT00651261; CALGB 10603) showed that midostaurin combined with standard chemotherapy significantly improved outcomes in patients with FMS-like tyrosine kinase 3 (FLT3)–mutated acute myeloid leukemia (AML), compared with placebo. In this post hoc subgroup analysis from the trial, we evaluated the impact of midostaurin in 163 patients with FLT3-tyrosine kinase domain (TKD) mutations. At a median follow-up of 60.7 months (95% CI, 55.0-70.8), the 5-year event-free survival (EFS) rate was significantly higher in patients treated with midostaurin than in those treated with placebo (45.2% vs 30.1%; P = .044). A trend toward improved disease-free survival was also observed with midostaurin (67.3% vs 53.4%; P = .089), whereas overall survival (OS) was similar in the 2 groups. Patients with AML and NPM1mut/FLT3-TKDmut or core binding factor (CBF)–rearranged/FLT3-TKDmut genotypes had significantly prolonged OS with or without censoring at hematopoietic cell transplantation (HCT), compared with NPM1WT/CBF-negative AMLs. The multivariable model for OS and EFS adjusted for allogeneic HCT in first complete remission as a time-dependent covariable, revealed NPM1 mutations and CBF rearrangements as significant favorable factors. These data show that NPM1 mutations or CBF rearrangements identify favorable prognostic groups in patients with FLT3-TKD AMLs, independent of other factors, also in the context of midostaurin treatment.

AbstractWe previously demonstrated that cancer‐associated fibroblasts (CAFs) promoted the proliferation of gallbladder cancer (GBC) cells, but the mechanism is not clear. Neuropilin‐1 (NRP‐1) plays an important role in various malignancies as transmembrane glycoprotein. Our goal was to reveal the relationship between CAFs and NRP‐1 and their potential functions in GBC. In this study, we found NRP‐1 was overexpressed in GBC tissue, associated with poor survival and was up‐regulated by CAFs. The cytokine array cluster analysis revealed IL‐8 secreted by CAFs facilitated the up‐regulation of NRP‐1 in tumour cells. NRP‐1 knockdown suppressed tumour growth in vivo. Gene expression microarray analysis showed 581 differentially regulated genes under NRP‐1 knockdown conditions. Ingenuity pathway analysis demonstrated that NRP‐1 knockdown may inhibit tumour progression by affecting cell proliferation. We then confirmed that NRP‐1 knockdown in NOZ and GBC‐SD cells significantly inhibited cell proliferation. Additionally, the IL‐8 mediated MDM2 and CCNA2 expression were affected by NRP‐1 knockdown. Our findings suggested that NRP‐1 was up‐regulated by CAF‐secreted IL‐8, which subsequently promoted GBC cell proliferation, and these molecules may serve as useful prognostic biomarkers and therapeutic targets for GBC.

AbstractThromboembolic and infectious complications stemming from the use of cardiovascular medical devices are still common and result in significant morbidity and mortality. There is no strategy to date that effectively addresses both challenges at the same time. Various surface modification strategies (e.g., silver, heparin, and liquid‐impregnated surfaces) are proposed yet each has several limitations and shortcomings. Here, it is shown that the incorporation of an ultrathin and mechanically robust hydrogel layer reduces bacterial adhesion to medical‐grade tubing by 95%. It is additionally demonstrated, through a combination of in vitro and in vivo tests, that the hydrogel layer significantly reduces the formation and adhesion of blood clots to the tubing without affecting the blood's intrinsic clotting ability. The adhesion of clots to the tubing walls is reduced by over 90% (in vitro model), which results in an ≈60% increase in the device occlusion time (time before closure due to clot formation) in an in vivo porcine model. The advantageous properties of this passive coating make it a promising surface material candidate for medical devices interfacing with blood.

Abstract Extensive biological and clinical evidence supports the notion many CRC tumors are addicted to EGFR/KRAS/MAPK signaling. For example, mutations in KRAS, BRAF and other MAPK pathway components confer intrinsic or acquired resistance to anti-EGFR therapy. However, a significant proportion of acquired resistance cases have remained unexplained. ARID1A mutations are found in approximately 11% of CRC tumors, but a connection between ARID1A mutations and EGFR/MAPK signaling activation in CRC has not been previously suspected. By leveraging the genomic biomarker data collected from 333 patients at baseline and at progression who participated in the CALGB/SWOG 80405 trial, we found that mutations in ARID1A, a key component of SWI/SNF complex, were enriched in the cell free DNA of 6/16 of the patients whose tumors had become resistant to anti-EGFR therapy with ARID1A mutations detected at either timepoint (adj. p = 0.03, OR = 0.09, two-tailed fisher's exact test). In contrast, there was no evidence of enriched ARID1A mutations in patients treated with bevacizumab. To investigate the potential role of a broader ARID1A deficiency phenotype in resistance to cetuximab therapy, we developed an ARID1A mutant-like signature from TCGA that captures the transcriptional profile characteristic of ARID1A mutants. Using this signature to stratify CALGB patients based on gene expression data collected on tissue at diagnosis, we also found patients with an ARID1A mutant-like gene expression profile had worst outcome in patients treated with cetuximab than bevacizumab with adjustment for established clinical variables for both OS [p = 0.0002, hazard ratio (HR) 6.2, 95% confidence interval (CI) 2.4-16], and PFS [p = 0.0008, HR 4.7 (1.9 -12)], suggesting that ARID1A mutations may be also a mechanism of intrinsic resistance to anti-EGFR therapies. Gene expression analysis demonstrated that ARID1A deficiency leads to re-activation of an EGFR-like signature, suggesting reactivation of this pathway as a possible mechanism of resistance. Furthermore, CRISPR knockout of ARID1A in the cetuximab-sensitive CRC cell line NCI-H508 conferred elevated MAPK signaling relative to parental line and resistance to cetuximab in culture. Consistent with these findings, we also observed strong mutual exclusivity between ARID1A mutations and mutations in the EGFR/MAPK signaling pathway in more than 40,000 lung and colorectal cancer patients profiled in the FoundationCore® database. Strikingly, in lung cancers where EGFR mutations structural variants (SV) are more prevalent, EGFR SV was the top mutually exclusive alteration with ARID1A mutations in lung cancers. Of 5980 lung cancer patients with ARID1A and/or EGFR SVs, only 100 patients (1.7%) had both SVs. Taken together, our data suggest that ARID1A loss-of-function mutations may promote resistance to cetuximab by driving an EGFR-like transcription program in the absence of ligand-dependent activation of EGFR. Our results suggest that ARID1A defects could be potentially used as an exclusion biomarker for cetuximab treatment decisions, and they provide a rationale for exploring therapeutic MAPK inhibition in ARID1A mutant CRC patients. Citation Format: Radia Marie Johnson, Xueping Qu, Joshua Thomas, Yvonne Kschonsak, Ling-Yuh Huw, Fang-Shu Ou, Ethan Sokol, Nnamdi Ihuegbu, Oliver Zill, Omar Kabbarah, Anneleen Daemen, Richard Bourgon, Alan Venook, Federico Innocenti, Heinz-Josef Lenz, Felipe de Sousa e Melo, Carlos Bais. ARID1A mutations induce an EGFR-like gene expression signature and confer intrinsic and acquired resistance to cetuximab treatment in first line metastatic CRC [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-063.

Abstract Objectives: Endometrial cancer (EC) is the most common gynecological cancer in the developed countries with rising incidence rates. However, the knowledge about targeted therapies that can improve response rates to chemotherapy in EC is limited. Of the cancer afflicting women, women with metabolic disorders such as diabetes and obesity have an increased risk of developing EC. 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), a glycolytic enzyme, is found to be highly expressed in many solid tumors. This study aimed to investigate the role and molecular mechanism of PFKFB3 in endometrial cancer. Methods: HEC-1B and ARK-2 endometrial cancer cell lines were used as models to evaluate the potential antitumor effects of pharmacological (treatment with PFK158, a selective PFKFB3 inhibitor) and genetic (PFKFB3 knockdown using CRISPR/Cas9 technology) inhibition of PFKFB3 on EC. In vitro, we evaluated the effects of PFKFB3 inhibition, and its synergistic effects when combined with carboplatin (CBPt) or cisplatin on cell viability, glucose metabolism, autophagy, apoptosis, and changes of cell signaling using MTT and colony formation assays, Chou-Talalay methodology, immunofluorescence assay, flow cytometry and western blotting. In vivo, two EC subcutaneous xenograft models derived from HEC-1B and ARK-2 cell lines were used to investigate the effect of single-agent PFK158 and in combination with CBPt on tumor growth, followed by western blotting, TUNEL and immunohistochemistry staining of excised tumor tissue. Results: Targeting PFKFB3 via PFK158 considerably reduced glucose uptake, ATP production, lactate release in EC cell lines. In vitro, inhibition of PFKFB3 induced cell death and synergistically enhanced CBPt/cisplatin sensitivity in EC cell lines by suppressing cell viability, inducing autophagy and apoptosis in a time- and dose-dependent manner. In vivo xenograft studies revealed that treatment with PFK158, either alone or in combination with CBPt, led to a marked reduction in tumor growth. In addition, PFK158 caused significant upregulation of cleaved PARP, cleaved caspase 3, and reduction of mTOR, Akt, ERK phosphorylation levels, both in vitro and in vivo. Conclusions: Our results indicate that PFKFB3 plays a prominent role in the growth and chemoresistance in EC cells. Therefore, a selective PFKFB3 inhibitor or in combination with chemotherapy, may be used as a novel therapeutic strategy for patients with chemoresistant EC. Citation Format: Yinan Xiao, Ling Jin, Sayantani Sarkar Bhattacharya, Julie Staub, Chaolin Deng, Xiaoling Fang, Viji Shridhar. Inhibition of 6-Phosphofructo-2-kinase (PFKFB3) induces cell death and synergistically enhances chemosensitivity in endometrial cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6222.

Abstract Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with dismal clinical outcomes. Conventional chemotherapies such cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) and hyperfractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone alternating with high-dose cytarabine and methotrexate (CVAD) have been commonly used for the BPDCN treatment until a recent study showed promising outcomes in patients treated with SL-401 (Tagraxofusp). In this single-institution retrospective study, we identified a total of 49 consecutive BPDCN patients. Among 42 patients who received treatment, hyper-CVAD regimen was associated with higher complete response rate compared with CHOP-based regimens or SL-401 (91% vs 50% vs 50%), although the difference did not achieve statistical significance. Furthermore, there was no significant overall survival (OS) difference between patients treated with SL-401 vs other chemotherapies as their first-line treatment (hazard ratio = 1.597; 95% CI, 0.460-5.548; P = .431). Of note, patients who received allogeneic stem cell transplant (allo-SCT) had significantly longer OS (hazard ratio = 0.160; 95% CI, 0.0453-0.56; P = .041). Extent of disease (skin vs bone marrow vs both) or younger age (<60 years old) did not have significant prognostic impact on OS. Collectively, our study confirmed the survival benefit of allo-SCT and suggests that conventional and intensive chemotherapies such as CHOP and hyper-CVAD as well as SL-401 would be comparable first-line choice for the BPDCN patients.

Abstract BackgroundDeep venous thrombosis (DVT) is a severe complication of the coronavirus disease 2019 (COVID-19). It may interfere with COVID-19 treatment and delay the recovery, but there is less data about the anticoagulant therapy and sex difference of VTE in patients with COVID-19. The purpose of this study is to study the prevalence, risk factors, anticoagulant therapy and sex difference of deep venous thrombosis (DVT) in patients with COVID-19.MethodsThe enrolled 121 patients were confirmed positive for COVID-19. All suspected patients with a high Caprini index (≥4) or PADUA index (≥4) received color Doppler Ultrasound (US) to screen DVT in both lower extremities. Clinical characteristics of DVT-COVID-19 patients were analyzed. Multivariate logistic regression was performed to identify risk factors related to DVT in COVID-19 patients. The distribution of DVT locations, anticoagulation therapy with sex difference, and the outcomes were also analyzed.ResultsDVT was found in 48% asymptomatic COVID-19 patients with increased PAUDA index or Caprini index by US scanning. Multivariate logistic regression determined that age, CRP and baseline D-dimer were risk factors among COVDI-19 patients. Although the most common DVT location was infrapopliteal (Class I and Class II), higher mortality in DVT-COVID-19 patients was confirmed. DVT-COVID-19 patients presented significant increases in the CRP, neutrophil count and D-dimer throughout the whole inpatient period compared to non-DVT-COVID-19 patients. Although anticoagulation therapy accelerated the recovery of lymphocytopenia condition in DVT patients, men DVT-COVID-19 patients showed higher CRP and neutrophil count vs. lymphocyte count (N/L) ratio but lower lymphocyte count compared to women DVT-COVID-19 patients. ConclusionsDVT is common in COVID-19 patients with high risk factors, especially for older age, higher CRP and baseline D-dimer populations. It is important to consider sex differences in the anticoagulant therapy among DVT-COVID-19 patients.