Distinct p53 transcriptional programs dictate acute DNA-damage responses and tumor suppression.

The molecular basis for p53-mediated tumor suppression remains unclear. Here, to elucidate mechanisms of p53 tumor suppression, we use knockin mice expressing an allelic series of p53 transcriptional activation mutants. Microarray analysis reveals that one mutant, p53(25,26), is severely compromised for transactivation of most p53 target genes, and, moreover, p53(25,26) cannot induce G(1)-arrest or apoptosis in response to acute DNA damage. Surprisingly, p53(25,26) retains robust activity in senescence and tumor suppression, indicating that efficient transactivation of the majority of known p53 targets is dispensable for these pathways. In contrast, the transactivation-dead p53(25,26,53,54) mutant cannot induce senescence or inhibit tumorigenesis, like p53 nullizygosity. Thus, p53 transactivation is essential for tumor suppression but, intriguingly, in association with a small set of novel p53 target genes. Together, our studies distinguish the p53 transcriptional programs involved in acute DNA-damage responses and tumor suppression-a critical goal for designing therapeutics that block p53-dependent side effects of chemotherapy without compromising p53 tumor suppression.

Moralization of E-cigarette Use and Regulation: A Mixed-Method Computational Analysis of Opinion Polarization.

E-cigarette use, or vaping, is undergoing a process of moralization in which issues about vaping evolve from being morally neutral to having discernible moral implications. Using Moral Foundations Theory, this study compared the moral narratives underlying polarized views about e-cigarette use and regulation. We integrated computational and human strategies by conducting the Chow test on the time series data and classification, topic modeling, and Chi-square tests on posts (N = 2,669) from 26 pro-vaping and 19 anti-vaping Facebook Pages. The observation period (August 1, 2019 to March 5, 2020) encompassed the outbreak of "e-cigarette or vaping product use associated lung injury" (EVALI), deaths and subsequent legislation. Results revealed that pro-vaping posts were more likely than anti-vaping posts to mention Fairness/cheating and Authority/subversion, involving a conspiracy belief in an "e-cigarettes vs. Big Tobacco" rivalry, while anti-vaping posts were more likely to mention Sanctity/degradation. There were no significant differences between pro-vaping and anti-vaping posts in the likelihood of mentioning Care/harm or Loyalty/betrayal. Nevertheless, according to the topic modeling results, the use of moral foundations varied between pro-vaping and anti-vaping narratives, with the meanings of Care/harm and Loyalty/betrayal dependent on the post author's group affiliation. Health interventions can tailor persuasive messages to different moral values and debunk misinformation about public health policies to mitigate the vaping epidemic. Theoretical implications are also discussed.

Phase 1 study of single-agent WNT974, a first-in-class Porcupine inhibitor, in patients with advanced solid tumours.

BACKGROUND: This Phase 1 study assessed the safety and efficacy of the Porcupine inhibitor, WNT974, in patients with advanced solid tumours. METHODS: Patients (n = 94) received oral WNT974 at doses of 5-30 mg once-daily, plus additional dosing schedules. RESULTS: The maximum tolerated dose was not established; the recommended dose for expansion was 10 mg once-daily. Dysgeusia was the most common adverse event (50% of patients), likely resulting from on-target Wnt pathway inhibition. No responses were seen by Response Evaluation Criteria in Solid Tumors (RECIST) v1.1; 16% of patients had stable disease (median duration 19.9 weeks). AXIN2 expression by RT-PCR was reduced in 94% of paired skin biopsies (n = 52) and 74% of paired tumour biopsies (n = 35), confirming inhibition of the Wnt pathway. In an exploratory analysis, an inverse association was observed between AXIN2 change and immune signature change in paired tumour samples (n = 8). CONCLUSIONS: Single-agent WNT974 treatment was generally well tolerated. Biomarker analyses suggest that WNT974 may influence immune cell recruitment to tumours, and may enhance checkpoint inhibitor activity. CLINICAL TRIAL REGISTRATION: NCT01351103.

Enhanced targeting of CML stem and progenitor cells by inhibition of porcupine acyltransferase in combination with TKI.

Tyrosine kinase inhibitor (TKI) treatment of chronic myeloid leukemia (CML) has limited efficacy against leukemia stem cells (LSC) responsible for disease propagation, and most CML patients require continued TKI treatment to maintain remission. LSC maintenance is related, at least in part, to signals from the bone marrow microenvironment (BMM). Our previous studies have shown that Wnt signaling from the BMM contributes to preservation of CML LSC following TKI treatment. Secretion of Wnt ligands requires their modification by the O-acyl transferase Porcupine (PORCN). Here we investigated the activity of a potent and selective PORCN inhibitor, WNT974, against CML stem and progenitor cells. WNT974 efficiently antagonized Wnt signaling in human CML CD34+ cells, and in combination with the TKI nilotinib (NIL) significantly enhanced inhibition of proliferation and colony-forming potential of CML stem and progenitor cells and reduced their growth in immunodeficient mice in vivo, in comparison with NIL alone. Treatment of transgenic CML mice in vivo with NIL in combination with WNT974 significantly reduced leukemic stem and progenitor cell numbers, reduced regeneration of leukemic long-term hematopoietic stem cells in secondary transplant recipients, and enhanced survival of mice after discontinuation of treatment, in comparison with NIL alone. CML progenitors demonstrated enhanced sensitivity to Wnt stimulation, associated with increased expression of the FZD4 receptor. FZD4 knockdown inhibited CML progenitor growth. These results support further investigation of PORCN targeting to inhibit Wnt secretion and signaling and enhance targeting of CML stem cells while sparing their normal counterparts.

Complete nucleotide sequence of clematis chlorotic mottle virus, a new member of the family Tombusviridae.

Clematis chlorotic mottle virus (ClCMV) is a previously undescribed virus associated with symptoms of yellow mottling and veining, chlorotic ring spots, line pattern mosaics, and flower distortion and discoloration on ornamental Clematis. The ClCMV genome is 3,880 nt in length with five open reading frames (ORFs) encoding a 27-kDa protein (ORF 1), an 87-kDa replicase protein (ORF 2), two centrally located movement proteins (ORF 3 and 4), and a 37-kDa capsid protein (ORF 5). Based on morphological, genomic, and phylogenetic analysis, ClCMV is predicted to be a member of the genus Pelarspovirus in the family Tombusviridae.

Functional epigenetics approach identifies BRM/SMARCA2 as a critical synthetic lethal target in BRG1-deficient cancers.

Defects in epigenetic regulation play a fundamental role in the development of cancer, and epigenetic regulators have recently emerged as promising therapeutic candidates. We therefore set out to systematically interrogate epigenetic cancer dependencies by screening an epigenome-focused deep-coverage design shRNA (DECODER) library across 58 cancer cell lines. This screen identified BRM/SMARCA2, a DNA-dependent ATPase of the mammalian SWI/SNF (mSWI/SNF) chromatin remodeling complex, as being essential for the growth of tumor cells that harbor loss of function mutations in BRG1/SMARCA4. Depletion of BRM in BRG1-deficient cancer cells leads to a cell cycle arrest, induction of senescence, and increased levels of global H3K9me3. We further demonstrate the selective dependency of BRG1-mutant tumors on BRM in vivo. Genetic alterations of the mSWI/SNF chromatin remodeling complexes are the most frequent among chromatin regulators in cancers, with BRG1/SMARCA4 mutations occurring in ∼10-15% of lung adenocarcinomas. Our findings position BRM as an attractive therapeutic target for BRG1 mutated cancers. Because BRG1 and BRM function as mutually exclusive catalytic subunits of the mSWI/SNF complex, we propose that such synthetic lethality may be explained by paralog insufficiency, in which loss of one family member unveils critical dependence on paralogous subunits. This concept of "cancer-selective paralog dependency" may provide a more general strategy for targeting other tumor suppressor lesions/complexes with paralogous subunits.

A Comparison Between Caucasians and African Americans in Willingness to Participate in Cancer Clinical Trials: The Roles of Knowledge, Distrust, Information Sources, and Religiosity.

This study aims to (a) examine the roles of knowledge, distrust in medical professionals, information sources, and 2 dimensions of religiosity (i.e., religious activity and religious belief) in influencing willingness to participate (WTP) in cancer clinical trials and to (b) compare the results for Caucasians and African Americans in order to inform future recruitment. An online survey was fielded via a Knowledge Networks panel with a nationally representative sample including 478 Caucasians and 173 African Americans. The results showed that distrust in medical professionals was a strong barrier to WTP for both ethnic groups, whereas factual knowledge about trial procedures was not associated with WTP for either ethnic group. Seeking trial information from doctors was positively associated with WTP for Caucasians; seeking trial information from hospitals was positively associated with WTP for African Americans. More interestingly, levels of religious activity negatively predicted WTP for Caucasians but positively predicted WTP for African Americans. Self-reported religious belief was not associated with WTP for either ethnic group. In sum, although distrust is a common barrier to WTP, the influence of preferred information sources and religious activity on WTP varies as a function of ethnicity.

Inactivating mutations of RNF43 confer Wnt dependency in pancreatic ductal adenocarcinoma.

A growing number of agents targeting ligand-induced Wnt/ß-catenin signaling are being developed for cancer therapy. However, clinical development of these molecules is challenging because of the lack of a genetic strategy to identify human tumors dependent on ligand-induced Wnt/ß-catenin signaling. Ubiquitin E3 ligase ring finger 43 (RNF43) has been suggested as a negative regulator of Wnt signaling, and mutations of RNF43 have been identified in various tumors, including cystic pancreatic tumors. However, loss of function study of RNF43 in cell culture has not been conducted, and the functional significance of RNF43 mutations in cancer is unknown. Here, we show that RNF43 inhibits Wnt/ß-catenin signaling by reducing the membrane level of Frizzled in pancreatic cancer cells, serving as a negative feedback mechanism. Inhibition of endogenous Wnt/ß-catenin signaling increased the cell surface level of Frizzled. A panel of 39 pancreatic cancer cell lines was tested for Wnt dependency using LGK974, a selective Porcupine inhibitor being examined in a phase 1 clinical trial. Strikingly, all LGK974-sensitive lines carried inactivating mutations of RNF43. Inhibition of Wnt secretion, depletion of ß-catenin, or expression of wild-type RNF43 blocked proliferation of RNF43 mutant but not RNF43-wild-type pancreatic cancer cells. LGK974 inhibited proliferation and induced differentiation of RNF43-mutant pancreatic adenocarcinoma xenograft models. Our data suggest that mutational inactivation of RNF43 in pancreatic adenocarcinoma confers Wnt dependency, and the presence of RNF43 mutations could be used as a predictive biomarker for patient selection supporting the clinical development of Wnt inhibitors in subtypes of cancer.

Targeting Wnt-driven cancer through the inhibition of Porcupine by LGK974.

Wnt signaling is one of the key oncogenic pathways in multiple cancers, and targeting this pathway is an attractive therapeutic approach. However, therapeutic success has been limited because of the lack of therapeutic agents for targets in the Wnt pathway and the lack of a defined patient population that would be sensitive to a Wnt inhibitor. We developed a screen for small molecules that block Wnt secretion. This effort led to the discovery of LGK974, a potent and specific small-molecule Porcupine (PORCN) inhibitor. PORCN is a membrane-bound O-acyltransferase that is required for and dedicated to palmitoylation of Wnt ligands, a necessary step in the processing of Wnt ligand secretion. We show that LGK974 potently inhibits Wnt signaling in vitro and in vivo, including reduction of the Wnt-dependent LRP6 phosphorylation and the expression of Wnt target genes, such as AXIN2. LGK974 is potent and efficacious in multiple tumor models at well-tolerated doses in vivo, including murine and rat mechanistic breast cancer models driven by MMTV-Wnt1 and a human head and neck squamous cell carcinoma model (HN30). We also show that head and neck cancer cell lines with loss-of-function mutations in the Notch signaling pathway have a high response rate to LGK974. Together, these findings provide both a strategy and tools for targeting Wnt-driven cancers through the inhibition of PORCN.

Propagation of Information About Preexposure Prophylaxis (PrEP) for HIV Prevention Through Twitter.

Previous literature has suggested that examining Twitter messages can be productive for studying how the public shares and spreads health information on social media. Preexposure prophylaxis (PrEP) is a promising approach to HIV prevention, yet there are many issues that may influence its effective implementation. This study examined social representations of PrEP on Twitter. One thousand four hundred and thirty-five Tweets were collected and 774 English Tweets were content-analyzed to explore propagation of various issues around daily oral PrEP, as well as characteristics of the sources of those Tweets. We also examined how Twitter message content influenced information propagation. Our findings revealed that PrEP-related information on Twitter covered a wide range of issues, and individual users constituted the majority of the Tweet creators among all the sources, including news media, nonprofit and academic groups, and commercial entities. Using Poisson regression, we also found that a Tweet's affective tone was a significant predictor of message propagation frequency. Implications for health practitioners are discussed.

Telomerase modulates Wnt signalling by association with target gene chromatin.

Stem cells are controlled, in part, by genetic pathways frequently dysregulated during human tumorigenesis. Either stimulation of Wnt/beta-catenin signalling or overexpression of telomerase is sufficient to activate quiescent epidermal stem cells in vivo, although the mechanisms by which telomerase exerts these effects are not understood. Here we show that telomerase directly modulates Wnt/beta-catenin signalling by serving as a cofactor in a beta-catenin transcriptional complex. The telomerase protein component TERT (telomerase reverse transcriptase) interacts with BRG1 (also called SMARCA4), a SWI/SNF-related chromatin remodelling protein, and activates Wnt-dependent reporters in cultured cells and in vivo. TERT serves an essential role in formation of the anterior-posterior axis in Xenopus laevis embryos, and this defect in Wnt signalling manifests as homeotic transformations in the vertebrae of Tert(-/-) mice. Chromatin immunoprecipitation of the endogenous TERT protein from mouse gastrointestinal tract shows that TERT physically occupies gene promoters of Wnt-dependent genes. These data reveal an unanticipated role for telomerase as a transcriptional modulator of the Wnt/beta-catenin signalling pathway.

Relationship between operating room nursing staff expertise and patient outcomes.

This secondary analysis evaluated the association of operating room scrub staff expertise, based on frequency of working on a specific surgical procedure, with the development of surgical site infections. The odds of developing surgical site infections decreased by 5.7% (odds ratio = 0.943; 95% confidence interval, 0.834-1.067) with increased expertise, although a statistically significant association was not established (P = .354). The relationship between operating room scrub staff expertise and patient outcomes is important to understand.

Maintenance of adenomatous polyposis coli (APC)-mutant colorectal cancer is dependent on Wnt/beta-catenin signaling.

Persistent expression of certain oncogenes is required for tumor maintenance. This phenotype is referred to as oncogene addiction and has been clinically validated by anticancer therapies that specifically inhibit oncoproteins such as BCR-ABL, c-Kit, HER2, PDGFR, and EGFR. Identifying additional genes that are required for tumor maintenance may lead to new targets for anticancer drugs. Although the role of aberrant Wnt pathway activation in the initiation of colorectal cancer has been clearly established, it remains unclear whether sustained Wnt pathway activation is required for colorectal tumor maintenance. To address this question, we used inducible ß-catenin shRNAs to temporally control Wnt pathway activation in vivo. Here, we show that active Wnt/ß-catenin signaling is required for maintenance of colorectal tumor xenografts harboring APC mutations. Reduced tumor growth upon ß-catenin inhibition was due to cell cycle arrest and differentiation. Upon reactivation of the Wnt/ß-catenin pathway colorectal cancer cells resumed proliferation and reacquired a crypt progenitor phenotype. In human colonic adenocarcinomas, high levels of nuclear ß-catenin correlated with crypt progenitor but not differentiation markers, suggesting that the Wnt/ß-catenin pathway may also control colorectal tumor cell fate during the maintenance phase of tumors in patients. These results support efforts to treat human colorectal cancer by pharmacological inhibition of the Wnt/ß-catenin pathway.

Heterologous downregulation of vasopressin type 2 receptor is induced by transferrin.

Vasopressin (VP) binds to the vasopressin type 2 receptor (V2R) to trigger physiological effects including body fluid homeostasis and blood pressure regulation. Signaling is terminated by receptor downregulation involving clathrin-mediated endocytosis and V2R degradation. We report here that both native and epitope-tagged V2R are internalized from the plasma membrane of LLC-PK1 kidney epithelial cells in the presence of another ligand, transferrin (Tf). The presence of iron-saturated Tf (holo-Tf; 4 h) reduced V2R binding sites at the cell surface by up to 33% while iron-free (apo-Tf) had no effect. However, no change in green fluorescent protein-tagged V2R distribution was observed in the presence of bovine serum albumin, atrial natriuretic peptide, or ANG II. Conversely, holo-Tf did not induce the internalization of another G protein-coupled receptor, the parathyroid hormone receptor. In contrast to the effect of VP, Tf did not increase intracellular cAMP or modify aquaporin-2 distribution in these cells, although addition of VP and Tf together augmented VP-induced V2R internalization. Tf receptor coimmunoprecipitated with V2R, suggesting that they interact closely, which may explain the additive effect of VP and Tf on V2R endocytosis. Furthermore, Tf-induced V2R internalization was abolished in cells expressing a dominant negative dynamin (K44A) mutant, indicating the involvement of clathrin-coated pits. We conclude that Tf can induce heterologous downregulation of the V2R and this might desensitize VP target cells without activating downstream V2R signaling events. It also provides new insights into urine-concentrating defects observed in rat models of hemochromatosis.

Vasopressin induces apical expression of caveolin in rat kidney collecting duct principal cells.

Caveolin (Cav)1 is expressed in the basolateral membrane domain of renal collecting duct (CD) principal cells (PCs), where it is associated with caveolae. To reveal any potential involvement of Cav1 in vasopressin signaling, we used specific monoclonal and polyclonal antibodies to examine its localization in CD PCs of Brattleboro (BB) rats treated with vasopressin (DDAVP). Compared with controls, immunofluorescence revealed a time-dependent increase in Cav1 expression in the apical membrane domain of PCs, where it overlapped with aquaporin-2 (AQP2). After 24 h of DDAVP treatment, Cav1 was visible as an increased number of small apical spots. The staining gradually became more extensive, and, after 2 wk of DDAVP, it occupied the majority of the apical membrane domain of many PCs. Cav1 also assumed an apical localization in PCs of DDAVP-treated Sprague-Dawley and Long-Evans rats. Similarly, Cav2 appeared at the apical pole of PCs after DDAVP treatment of BB, Sprague-Dawley, and Long-Evans rats. Immunogold electron microscopy confirmed bipolar Cav1 membrane expression in DDAVP-treated BB rats, whereas caveolae were only detected on the basolateral membrane. Immunoblot analysis of BB rat whole kidney homogenates revealed no significant increase in Cav1 levels in DDAVP-treated rats, suggesting that DDAVP induces Cav1 relocalization or modifies its targeting. We conclude that Cav1 and Cav2 trafficking and membrane localization are dramatically altered by the action of DDAVP. Importantly, the absence of apical caveolae indicates that while Cavs may have an as yet undetermined role in vasopressin-regulated signaling processes, this is probably unrelated to AQP2 internalization by caveolae.

Pten constrains centroacinar cell expansion and malignant transformation in the pancreas.

To determine the role of the phosphatidylinositol 3-kinase (PI3-K) pathway in pancreas development, we generated a pancreas-specific knockout of Pten, a negative regulator of PI3-K signaling. Knockout mice display progressive replacement of the acinar pancreas with highly proliferative ductal structures that contain abundant mucins and express Pdx1 and Hes1, two markers of pancreatic progenitor cells. Moreover, a fraction of these mice develop ductal malignancy. We provide evidence that ductal metaplasia results from the expansion of centroacinar cells rather than transdifferentiation of acinar cells. These results indicate that Pten actively maintains the balance between different cell types in the adult pancreas and that misregulation of the PI3-K pathway in centroacinar cells may contribute to the initiation of pancreatic carcinoma in vivo.

Restoration of p53 function leads to tumour regression in vivo.

Tumorigenesis is a multi-step process that requires activation of oncogenes and inactivation of tumour suppressor genes. Mouse models of human cancers have recently demonstrated that continuous expression of a dominantly acting oncogene (for example, Hras, Kras and Myc) is often required for tumour maintenance; this phenotype is referred to as oncogene addiction. This concept has received clinical validation by the development of active anticancer drugs that specifically inhibit the function of oncoproteins such as BCR-ABL, c-KIT and EGFR. Identifying additional gene mutations that are required for tumour maintenance may therefore yield clinically useful targets for new cancer therapies. Although loss of p53 function is a common feature of human cancers, it is not known whether sustained inactivation of this or other tumour suppressor pathways is required for tumour maintenance. To explore this issue, we developed a Cre-loxP-based strategy to temporally control tumour suppressor gene expression in vivo. Here we show that restoring endogenous p53 expression leads to regression of autochthonous lymphomas and sarcomas in mice without affecting normal tissues. The mechanism responsible for tumour regression is dependent on the tumour type, with the main consequence of p53 restoration being apoptosis in lymphomas and suppression of cell growth with features of cellular senescence in sarcomas. These results support efforts to treat human cancers by way of pharmacological reactivation of p53.

Safe at home: Acceptance of surveillance technology among caregivers for persons with dementia.

The increasing incidence of dementia calls for effective and innovative approaches to alleviate societal and personal burdens. Aging in place is a sustainable paradigm which ensures the best utilization of societal resources, supports caregivers, secures normalcy, and optimizes care for persons with dementia (PwD). Home-based surveillance technology can support PwD in safely aging in place. This study examines factors associated with the adoption of home-based surveillance technologies among unpaid dementia caregivers. Through an online survey (N = 203), we apply ordinal logistic regression to identify five variables that predict the likelihood of caregivers' surveillance technology adoption for dementia care. The predictors are caregivers': (1) trouble concerns about PwD, (2) online support group membership, (3) perceived social norms regarding surveillance technology use, (4) perceived usefulness of surveillance devices, and (5) depth of information and communication technologies (ICT) use. Theoretical and practical implications for dementia healthcare are discussed.

Thinking beyond the tumor cell: Nf1 haploinsufficiency in the tumor environment.

Deletion of both copies of the Nf1 gene in Schwann cells combined with Nf1 heterozygosity in the tumor environment promotes neurofibroma formation in mice.

Patient perceptions of missed nursing care.

BACKGROUND: A series of studies involving nursing staff perception have shown that a significant amount of standard nursing care is being "missed"-that is, aspects of required patient care are omitted or significantly delayed. A study was conducted to (1) determine the elements of nursing care that patients are able to report on and (2) to gain insight into the extent and type of missed nursing care experienced by a group of patients. METHODS: In-depth, semistructured, face-to-face interviews, guided by open-ended and interactive questions, were conducted with 38 inpatients on seven different patient care units in an acute care hospital. FINDINGS: For Question 1, elements were categorized as fully reportable (for example, mouth care, bathing, and pain medication), partially reportable (hand washing, vital signs, and patient education), or not reportable (nursing assessment, skin assessment, intravenous site care). For Question 2, patients identified mouth care, ambulation, discharge planning, patient education, listening to them, and being kept informed as frequently missing. Patients sometimes missed response to call lights and alarms, meal assistance, pain medication and follow-up, other medication administration, and repositioning. Nursing care identified as rarely missed were bathing, vital signs, and hand washing. CONCLUSIONS: There is a large area of care for which patients can give an account if they are cognizant of their surroundings and mentally able to do so. For certain aspects of care, patients' perceptions of missed care were similar to those of nursing staff. There is a need to link specific aspects of nursing care to patient outcomes to assist in determining how essential specific elements of nursing care are and the cost-benefit balance of completing them or not.