KRAS inhibition activates an actionable CD24 'don't eat me' signal in pancreas cancer.

KRAS G12C inhibitor (G12Ci) has produced encouraging, albeit modest and transient, clinical benefit in pancreatic ductal adenocarcinoma (PDAC). Identifying and targeting resistance mechanisms to G12Ci treatment is therefore crucial. To better understand the tumor biology of the KRAS G12C allele and possible bypass mechanisms, we developed a novel autochthonous KRAS G12C -driven PDAC model. Compared to the classical KRAS G12D PDAC model, the G12C model exhibit slower tumor growth, yet similar histopathological and molecular features. Aligned with clinical experience, G12Ci treatment of KRAS G12C tumors produced modest impact despite stimulating a 'hot' tumor immune microenvironment. Immunoprofiling revealed that CD24, a 'do-not-eat-me' signal, is significantly upregulated on cancer cells upon G12Ci treatment. Blocking CD24 enhanced macrophage phagocytosis of cancer cells and significantly sensitized tumors to G12Ci treatment. Similar findings were observed in KRAS G12D -driven PDAC. Our study reveals common and distinct oncogenic KRAS allele-specific biology and identifies a clinically actionable adaptive mechanism that may improve the efficacy of oncogenic KRAS inhibitor therapy in PDAC. Significance: Lack of faithful preclinical models limits the exploration of resistance mechanisms to KRAS G12C inhibitor in PDAC. We generated an autochthonous KRAS G12C -driven PDAC model, which revealed allele-specific biology of the KRAS G12C during PDAC development. We identified CD24 as an actionable adaptive mechanisms in cancer cells induced upon KRAS G12C inhibition and blocking CD24 sensitizes PDAC to KRAS inhibitors in preclinical models.

Histone demethylase KDM2A is a selective vulnerability of cancers relying on alternative telomere maintenance.

Telomere length maintenance is essential for cellular immortalization and tumorigenesis. 5% - 10% of human cancers rely on a recombination-based mechanism termed alternative lengthening of telomeres (ALT) to sustain their replicative immortality, yet there are currently no targeted therapies. Through CRISPR/Cas9-based genetic screens in an ALT-immortalized isogenic cellular model, here we identify histone lysine demethylase KDM2A as a molecular vulnerability selectively for cells contingent on ALT-dependent telomere maintenance. Mechanistically, we demonstrate that KDM2A is required for dissolution of the ALT-specific telomere clusters following recombination-directed telomere DNA synthesis. We show that KDM2A promotes de-clustering of ALT multitelomeres through facilitating isopeptidase SENP6-mediated SUMO deconjugation at telomeres. Inactivation of KDM2A or SENP6 impairs post-recombination telomere de-SUMOylation and thus dissolution of ALT telomere clusters, leading to gross chromosome missegregation and mitotic cell death. These findings together establish KDM2A as a selective molecular vulnerability and a promising drug target for ALT-dependent cancers.

Histone demethylase KDM2A is a selective vulnerability of cancers relying on alternative telomere maintenance.

Telomere length maintenance is essential for cellular immortalization and tumorigenesis. 5% - 10% of human cancers rely on a recombination-based mechanism termed alternative lengthening of telomeres (ALT) to sustain their replicative immortality, yet there are currently no targeted therapies. Through CRISPR/Cas9-based genetic screens in an ALT-immortalized isogenic cellular model, here we identify histone lysine demethylase KDM2A as a molecular vulnerability selectively for cells contingent on ALT-dependent telomere maintenance. Mechanistically, we demonstrate that KDM2A is required for dissolution of the ALT-specific telomere clusters following homology-directed telomere DNA synthesis. We show that KDM2A promotes de-clustering of ALT multitelomeres through facilitating isopeptidase SENP6-mediated SUMO deconjugation at telomeres. Inactivation of KDM2A or SENP6 impairs post-recombination telomere de-SUMOylation and thus dissolution of ALT telomere clusters, leading to gross chromosome missegregation and mitotic cell death. These findings together establish KDM2A as a selective molecular vulnerability and a promising drug target for ALT-dependent cancers.

The efficiency of human umbilical cord mesenchymal stem cells as a salvage treatment for steroid-refractory acute graft-versus-host disease.

Acute graft-versus-host disease (aGVHD) is a life-threatening complication after hematopoietic stem cell transplantation (HSCT) and is primarily treated with steroids. However, there is no standard treatment for steroid-refractory acute graft-versus-host disease (SR-aGVHD). Although mesenchymal stem cells (MSCs) have proven effective for SR-aGVHD, few reports have focused on human umbilical cord blood-derived MSCs (hUCB-MSCs). Here, we report on the efficiency of hUCB-MSCs as the salvage therapy for SR-aGVHD in 54 patients. The overall response rate (ORR) reached 59.3% (32/54) 28 days later. Twenty-four patients achieved complete remission (CR), and 8 achieved partial remission (PR). The median follow-up time after the initiation of hUCB-MSC treatment was 19.3 (0.6-59.0) months. The probability of overall survival (OS) and progression-free survival (PFS) was 60.9% (47.4-74.4%, 95% CI) and 58.8% (45.3-72.3%, 95% CI), respectively, while that of GVHD/relapse-free survival (GRFS) was only 30.8% (17.86-43.74%, 95% CI). Multivariate analysis revealed that response on Day 28 was an independent favorable prognostic factor (OS, P < 0.001; PFS, P < 0.001; GRFS, P = 0.001), but an age of ≥ 18 years suggested an unfavorable long-term prognosis (OS, P < 0.001; PFS, P < 0.001; GRFS, P = 0.003). In addition, liver involvement was adversely associated with PFS (P = 0.021) and GRFS (P = 0.009). An infused MNC ≥ 8.66 × 108/kg was also detrimental to GRFS (P = 0.031). Collectively, our results support hUCB-MSCs as an effective treatment for SR-aGVHD.

Recurrent Novel P2RY8/IGH Translocations in B-Lymphoblastic Leukemia/Lymphoma.

Translocations involving the immunoglobulin heavy chain (IGH) locus are common abnormalities in B-lymphoblastic leukemia/lymphoma (B-ALL) and multiple myeloma. These rearrangements result in a juxtaposition of IGH enhancers to the vicinity of oncogenes, such as MYC and CRLF2, leading to the upregulation of oncogenes. Here, we identified recurrent novel P2RY8/IGH translocations in three B-ALL patients by transcriptome sequencing. Noncoding exon 1 of P2RY8 was translocated to different sites of the IGH gene, resulting in transcripts of P2RY8/IGHM, P2RY8/IGHV, and P2RY8/IGHD. However, a high expression level of truncated P2RY8 was observed in the patients compared with healthy donors, which might be related to the aggressive clinical course and inferior outcome. In summary, we described recurrent novel P2RY8/IGH translocations with high expression levels of P2RY8, which may contribute to the guidelines for clinical diagnosis and treatment.

Anti-GD2 antibody dinutuximab inhibits triple-negative breast tumor growth by targeting GD2+ breast cancer stem-like cells.

BACKGROUND: Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype with no effective standard therapy. Breast cancer stem-like cells (BCSCs) in primary TNBCs are reported to be responsible for metastatic spread of the disease and resistance to chemotherapy, but no available therapeutic tools target BCSCs. We previously reported that the ganglioside GD2 is highly expressed on BCSCs and that inhibition of its expression hampers TNBC growth. We therefore hypothesized that the anti-GD2 antibody dinutuximab (ch14.18) targets GD2+ BCSCs and inhibits TNBC growth. METHOD: To test our hypothesis, we first determined GD2 expression via immunohistochemistry in frozen primary tumor samples from patients with TNBC (n=89). Then, we examined the effects of dinutuximab on TNBC cell adhesion, migration, and mammosphere formation in vitro and on tumor growth in vivo using TNBC cell-line and patient-derived xenograft (PDX) models. RESULTS: We found that GD2 was expressed in around 60% of primary TNBC tumors at variable levels and was associated with worse overall survival of patients with TNBC (p=0.002). GD2 was found to be expressed in tumors and stroma, but normal ducts and lobules in adjacent tissues have shown low or no GD2 staining, indicating that GD2 is potentially a novel biomarker for tumor and its microenvironment. Treatment with dinutuximab significantly decreased adhesion and migration of MDA-MB-231 and SUM159 TNBC cells. Moreover, dinutuximab treatment inhibited mTOR signaling, which has been shown to be regulated by GD2 in BCSCs. Dinutuximab also reduced tumor growth in nude mice bearing TNBC cell-line xenografts. Finally, dinutuximab in combination with activated natural killer cells inhibited tumor growth in a TNBC PDX model and improved overall survival of tumor-bearing mice. CONCLUSIONS: Dinutuximab successfully eliminated GD2+ cells and reduced tumor growth in both in vivo models. Our data provide proof-of-concept for the criticality of GD2 in BCSCs and demonstrate the potential of dinutuximab as a novel therapeutic approach for TNBC.

Engineering of an enhanced synthetic Notch receptor by reducing ligand-independent activation.

Notch signaling is highly conserved in most animals and plays critical roles during neurogenesis as well as embryonic development. Synthetic Notch-based systems, modeled from Notch receptors, have been developed to sense and respond to a specific extracellular signal. Recent advancement of synNotch has shown promise for future use in cellular engineering to treat cancers. However, synNotch from Morsut et al. (2016) has a high level of ligand-independent activation, which limits its application. Here we show that adding an intracellular hydrophobic sequence (QHGQLWF, named as RAM7) present in native Notch, significantly reduced ligand-independent activation. Our enhanced synthetic Notch receptor (esNotch) demonstrates up to a 14.6-fold reduction in ligand-independent activation, without affecting its antigen-induced activation efficiency. Our work improves a previously reported transmembrane receptor and provides a powerful tool to develop better transmembrane signaling transduction modules for further advancement of eukaryotic synthetic biology.

[Correlation of toll-like receptor 3 and tumor necrosis factor-alpha with idiopathic fetal growth restriction.].

OBJECTIVE: To investigate the expression and the significance of toll-like receptor 3 (TLR-3) in placenta, tumor necrosis factor-alpha(TNF-alpha) in maternal and cord blood of idiopathic fetal growth restriction (IFGR), and their correlation with the pathogenesis of symmetric and asymmetric IFGR. METHODS: From April 2008 to April 2009, 42 primiparae of singleton pregnancy and their IFGR babies, who delivered at term through cesarean section, in the Third Affiliated Hospital of Zhengzhou University were enrolled. All subjectects were divided into symmetric IFGR group (n = 20) and asymmetric IFGR group (n = 22). Another 42 non-IFGR pairs were randomly selected as the control group. The polink-2 plus polymerized horseradish peroxidase (HRP) immunohistochemical method and the enzyme linked immunosorbent assay (ELISA) were applied to detect TLR-3 and TNF-alpha levels. RESULTS: (1) The expression of TLR-3 protein were observed in all maternal placenta of the three groups. TLR-3 essentially expressed in syncytiotrophoblasts and hofbouer cells in the symmetric IFGR and control group, but expressed mostly in hofbouer cells and less in syncytiotrophoblasts in the asymmetric IFGR group. (2) The expression of TLR-3 in the syncytiotrophoblasts of the symmetric and asymmetric IFGR group was significantly lower than in the control group (111 +/- 14 and 118 +/- 11 vs. 156 +/- 9, P < 0.01). The number of TLR-3 positive in Hofbourer cell in the symmetric IFGR group was lower than the control group (8.9 +/- 2.8 vs 17.5 +/- 2.8, P < 0.01), but the number in the asymmetric IFGR group was higher (23.8 +/- 3.7) compared with the control group (P < 0.01). (3) The TNF-alpha levels in the maternal and cord blood of the symmetric and the asymmetric group were higher than that of the control group [maternal: (90 +/- 10) microg/L and (86 +/- 11) microg/L vs. (73 +/- 9) microg/L; cord blood: (92 +/- 12) microg/L and (96 +/- 8) microg/L vs. (79 +/- 9) microg/L; P < 0.01]. (4) Neither symmetric nor the asymmetric IFGR group showed any correlations between the maternal and cord blood levels of TNF-alpha (P > 0.05). (5) Significant correlation was found between the TNF-alpha level of the cord blood and TLR-3 expression in the placenta in both the symmetric and asymmetric IFGR group (P < 0.05), but no relationship was found between the maternal blood TNF-alpha level and TLR-3 expression in the placenta (P > 0.05). CONCLUSIONS: The variantions of TLR-3 expression in placenta and the increased expression of TNF-alpha in cord blood are associated with the genesis IFGR. The reduced expression of TLR-3 may related to symmetric IFGR, while the increased TLR-3 level in hofbouer cells may lead to asymmetric IFGR.

Survey of sleep problems amongst Singapore children in a psychiatric setting.

BACKGROUND: Sleep problems are common among children and range from transient ones to chronic problems like snoring, somnambulism and bedwetting. Sleep problems in turn impact on children's health, learning, school performance, quality of life and are often closely related to mental health problems. Population based surveys have also revealed a strong association between sleep problems and behavioral and emotional symptoms in children. The objectives of our study were to estimate the prevalence of sleep problems in children and adolescents attending psychiatric services in Singapore and to identify the correlates of sleep problems in this population. METHODS: A total of 490 parents/guardians accompanying their children to the child guidance clinic consented to complete a questionnaire, which was used to collect both sociodemographic data and the frequency of sleep problems. These included sleep starts, confusional arousal, sleep talking, bruxism, sleep walking, sleep terrors, nightmares, sleep paralysis and nocturnal enuresis. Psychiatric diagnosis was determined from case record survey of the participating subjects. RESULTS: About 62.2% (95% CI 57.8%-66.6%) of the children suffered from at least one problem. Girls were significantly more likely to suffer from sleep problems when compared with boys (chi(2)=8.5, P<0.005). The significant predictors for sleep problems were gender, diagnosis of developmental disorders and a family history of sleep problems. CONCLUSIONS: The study highlights the need for child and adolescent psychiatrists to inquire about sleep problems since sleep disturbances of children are frequent and may not be self-reported.