Clonal dominance defines metastatic dissemination in pancreatic cancer.

Tumors represent ecosystems where subclones compete during tumor growth. While extensively investigated, a comprehensive picture of the interplay of clonal lineages during dissemination is still lacking. Using patient-derived pancreatic cancer cells, we created orthotopically implanted clonal replica tumors to trace clonal dynamics of unperturbed tumor expansion and dissemination. This model revealed the multifaceted nature of tumor growth, with rapid changes in clonal fitness leading to continuous reshuffling of tumor architecture and alternating clonal dominance as a distinct feature of cancer growth. Regarding dissemination, a large fraction of tumor lineages could be found at secondary sites each having distinctive organ growth patterns as well as numerous undescribed behaviors such as abortive colonization. Paired analysis of primary and secondary sites revealed fitness as major contributor to dissemination. From the analysis of pro- and nonmetastatic isogenic subclones, we identified a transcriptomic signature able to identify metastatic cells in human tumors and predict patients' survival.

Targeting DNA2 overcomes metabolic reprogramming in multiple myeloma.

DNA damage resistance is a major barrier to effective DNA-damaging therapy in multiple myeloma (MM). To discover mechanisms through which MM cells overcome DNA damage, we investigate how MM cells become resistant to antisense oligonucleotide (ASO) therapy targeting Interleukin enhancer binding factor 2 (ILF2), a DNA damage regulator that is overexpressed in 70% of MM patients whose disease has progressed after standard therapies have failed. Here, we show that MM cells undergo adaptive metabolic rewiring to restore energy balance and promote survival in response to DNA damage activation. Using a CRISPR/Cas9 screening strategy, we identify the mitochondrial DNA repair protein DNA2, whose loss of function suppresses MM cells' ability to overcome ILF2 ASO-induced DNA damage, as being essential to counteracting oxidative DNA damage. Our study reveals a mechanism of vulnerability of MM cells that have an increased demand for mitochondrial metabolism upon DNA damage activation.

Ether phospholipids are required for mitochondrial reactive oxygen species homeostasis.

Mitochondria are hubs where bioenergetics, redox homeostasis, and anabolic metabolism pathways integrate through a tightly coordinated flux of metabolites. The contributions of mitochondrial metabolism to tumor growth and therapy resistance are evident, but drugs targeting mitochondrial metabolism have repeatedly failed in the clinic. Our study in pancreatic ductal adenocarcinoma (PDAC) finds that cellular and mitochondrial lipid composition influence cancer cell sensitivity to pharmacological inhibition of electron transport chain complex I. Profiling of patient-derived PDAC models revealed that monounsaturated fatty acids (MUFAs) and MUFA-linked ether phospholipids play a critical role in maintaining ROS homeostasis. We show that ether phospholipids support mitochondrial supercomplex assembly and ROS production; accordingly, blocking de novo ether phospholipid biosynthesis sensitized PDAC cells to complex I inhibition by inducing mitochondrial ROS and lipid peroxidation. These data identify ether phospholipids as a regulator of mitochondrial redox control that contributes to the sensitivity of PDAC cells to complex I inhibition.

Targeting DNA2 Overcomes Metabolic Reprogramming in Multiple Myeloma.

DNA damage resistance is a major barrier to effective DNA-damaging therapy in multiple myeloma (MM). To discover novel mechanisms through which MM cells overcome DNA damage, we investigated how MM cells become resistant to antisense oligonucleotide (ASO) therapy targeting ILF2, a DNA damage regulator that is overexpressed in 70% of MM patients whose disease has progressed after standard therapies have failed. Here, we show that MM cells undergo an adaptive metabolic rewiring and rely on oxidative phosphorylation to restore energy balance and promote survival in response to DNA damage activation. Using a CRISPR/Cas9 screening strategy, we identified the mitochondrial DNA repair protein DNA2, whose loss of function suppresses MM cells' ability to overcome ILF2 ASO-induced DNA damage, as being essential to counteracting oxidative DNA damage and maintaining mitochondrial respiration. Our study revealed a novel vulnerability of MM cells that have an increased demand for mitochondrial metabolism upon DNA damage activation. STATEMENT OF SIGNIFICANCE: Metabolic reprogramming is a mechanism through which cancer cells maintain survival and become resistant to DNA-damaging therapy. Here, we show that targeting DNA2 is synthetically lethal in myeloma cells that undergo metabolic adaptation and rely on oxidative phosphorylation to maintain survival after DNA damage activation.

Cueing quality: Unpacking country-of-origin effects on intentions to vaccinate against COVID-19 in Taiwan.

While existing studies have reported and recognized country-of-origin effects on the intentions to vaccinate against COVID-19 among individual citizens in some countries, the causal mechanism behind such effects to inform public health policymakers remain unexplored. Adding up a quality cue explanation for such effects to the existing literature, the authors argue that individual consumers are less willing to get a vaccine designed and manufactured by a country with a significantly lower quality perception than other countries. A survey experiment that recruited a nationally representative sample of Taiwanese adults (n = 1951) between December 13, 2020 and January 11, 2021 was designed and conducted to test the argument. We find that all else equal, Taiwanese respondents were on average less likely to express stronger willingness to take a vaccine from China than from the US, Germany, and Taiwan. Furthermore, even when the intrinsic quality of the vaccine was held constant by the experimental design, respondents still had a significantly lower quality perception of the vaccine from China, both in terms of perceived protection and severe side effects. Further evidence from casual mediation analyses shows that about 33% and 11% of the total average causal effects of the "China" country-of-origin label on vaccine uptake intention were respectively mediated through the perceived efficacy of protection and perceived risk of experiencing severe side effects. We conclude that quality cue constitutes one of many casual mechanisms behind widely reported country-of-origin effects on intention to vaccinate against COVID-19.

Immune landscape of a genetically engineered murine model of glioma compared with human glioma.

Novel therapeutic strategies targeting glioblastoma (GBM) often fail in the clinic, partly because preclinical models in which hypotheses are being tested do not recapitulate human disease. To address this challenge, we took advantage of our previously developed spontaneous Qk/Trp53/Pten (QPP) triple-knockout model of human GBM, comparing the immune microenvironment of QPP mice with that of patient-derived tumors to determine whether this model provides opportunity for gaining insights into tumor physiopathology and preclinical evaluation of therapeutic agents. Immune profiling analyses and single-cell sequencing of implanted and spontaneous tumors from QPP mice and from patients with glioma revealed intratumoral immune components that were predominantly myeloid cells (e.g., monocytes, macrophages, and microglia), with minor populations of T, B, and NK cells. When comparing spontaneous and implanted mouse samples, we found more neutrophils and T and NK cells in the implanted model. Neutrophils and T and NK cells were increased in abundance in samples derived from human high-grade glioma compared with those derived from low-grade glioma. Overall, our data demonstrate that our implanted and spontaneous QPP models recapitulate the immunosuppressive myeloid-dominant nature of the tumor microenvironment of human gliomas. Our model provides a suitable tool for investigating the complex immune compartment of gliomas.

Economic evaluation for mass vaccination against COVID-19.

BACKGROUND: Vaccine is supposed to be the most effective means to prevent COVID-19 as it may not only save lives but also reduce productivity loss due to resuming pre-pandemic activities. Providing the results of economic evaluation for mass vaccination is of paramount importance for all stakeholders worldwide. METHODS: We developed a Markov decision tree for the economic evaluation of mass vaccination against COVID-19. The effectiveness of reducing outcomes after the administration of three COVID-19 vaccines (BNT162b2 (Pfizer-BioNTech), mRNA-1273 (Moderna), and AZD1222 (Oxford-AstraZeneca)) were modelled with empirical parameters obtained from literatures. The direct cost of vaccine and COVID-19 related medical cost, the indirect cost of productivity loss due to vaccine jabs and hospitalization, and the productivity loss were accumulated given different vaccination scenarios. We reported the incremental cost-utility ratio and benefit/cost (B/C) ratio of three vaccines compared to no vaccination with a probabilistic approach. RESULTS: Moderna and Pfizer vaccines won the greatest effectiveness among the three vaccines under consideration. After taking both direct and indirect costs into account, all of the three vaccines dominated no vaccination strategy. The results of B/C ratio show that one dollar invested in vaccine would have USD $13, USD $23, and USD $28 in return for Moderna, Pfizer, and AstraZeneca, respectively when health and education loss are considered. The corresponding figures taking value of the statistical life into account were USD $176, USD $300, and USD $443. CONCLUSION: Mass vaccination against COVID-19 with three current available vaccines is cost-saving for gaining more lives and less cost incurred.

Estimating global burden of COVID-19 with disability-adjusted life years and value of statistical life metrics.

BACKGROUND: Global burden of COVID-19 has not been well studied, disability-adjusted life years (DALYs) and value of statistical life (VSL) metrics were therefore proposed to quantify its impacts on health and economic loss globally. METHODS: The life expectancy, cases, and death numbers of COVID-19 until 30th April 2021 were retrieved from open data to derive the epidemiological profiles and DALYs (including years of life lost (YLL) and years loss due to disability (YLD)) by four periods. The VSL estimates were estimated by using hedonic wage method (HWM) and contingent valuation method (CVM). The estimate of willingness to pay using CVM was based on the meta-regression mixed model. Machine learning method was used for classification. RESULTS: Globally, DALYs (in thousands) due to COVID-19 was tallied as 31,930 from Period I to IV. YLL dominated over YLD. The estimates of VSL were US$591 billion and US$5135 billion based on HWM and CVM, respectively. The estimate of VSL increased from US$579 billion in Period I to US$2160 billion in Period IV using CVM. The higher the human development index (HDI), the higher the value of DALYs and VSL. However, there exits the disparity even at the same level of HDI. Machine learning analysis categorized eight patterns of global burden of COVID-19 with a large variation from US$0.001 billion to US$691.4 billion. CONCLUSION: Global burden of COVID-19 pandemic resulted in substantial health and value of life loss particularly in developed economies. Classifications of such health and economic loss is informative to early preparation of adequate resource to reduce impacts.

Medium-Chain Acyl-CoA Dehydrogenase Protects Mitochondria from Lipid Peroxidation in Glioblastoma.

Glioblastoma (GBM) is highly resistant to chemotherapies, immune-based therapies, and targeted inhibitors. To identify novel drug targets, we screened orthotopically implanted, patient-derived glioblastoma sphere-forming cells using an RNAi library to probe essential tumor cell metabolic programs. This identified high dependence on mitochondrial fatty acid metabolism. We focused on medium-chain acyl-CoA dehydrogenase (MCAD), which oxidizes medium-chain fatty acids (MCFA), due to its consistently high score and high expression among models and upregulation in GBM compared with normal brain. Beyond the expected energetics impairment, MCAD depletion in primary GBM models induced an irreversible cascade of detrimental metabolic effects characterized by accumulation of unmetabolized MCFAs, which induced lipid peroxidation and oxidative stress, irreversible mitochondrial damage, and apoptosis. Our data uncover a novel protective role for MCAD to clear lipid molecules that may cause lethal cell damage, suggesting that therapeutic targeting of MCFA catabolism may exploit a key metabolic feature of GBM. SIGNIFICANCE: MCAD exerts a protective role to prevent accumulation of toxic metabolic by-products in glioma cells, actively catabolizing lipid species that would otherwise affect mitochondrial integrity and induce cell death. This work represents a first demonstration of a nonenergetic role for dependence on fatty acid metabolism in cancer.This article is highlighted in the In This Issue feature, p. 2659.

Pooled library screening with multiplexed Cpf1 library.

Capitalizing on the inherent multiplexing capability of AsCpf1, we developed a multiplexed, high-throughput screening strategy that minimizes library size without sacrificing gene targeting efficiency. We demonstrated that AsCpf1 can be used for functional genomics screenings and that an AsCpf1-based multiplexed library performs similarly as compared to currently available monocistronic CRISPR/Cas9 libraries, with only one vector required for each gene. We construct the smallest whole-genome CRISPR knock-out library, Mini-human, for the human genome (n = 17,032 constructs targeting 16,977 protein-coding genes), which performs favorably compared to conventional Cas9 libraries.

Syndecan 1 is a critical mediator of macropinocytosis in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) remains recalcitrant to all forms of cancer treatment and carries a five-year survival rate of only 8%1. Inhibition of oncogenic KRAS (hereafter KRAS*), the earliest lesion in disease development that is present in more than 90% of PDACs, and its signalling surrogates has yielded encouraging preclinical results with experimental agents2-4. However, KRAS*-independent disease recurrence following genetic extinction of Kras* in mouse models anticipates the need for co-extinction strategies5,6. Multiple oncogenic processes are initiated at the cell surface, where KRAS* physically and functionally interacts to direct signalling that is essential for malignant transformation and tumour maintenance. Insights into the complexity of the functional cell-surface-protein repertoire (surfaceome) have been technologically limited until recently and-in the case of PDAC-the genetic control of the function and composition of the PDAC surfaceome in the context of KRAS* signalling remains largely unknown. Here we develop an unbiased, functional target-discovery platform to query KRAS*-dependent changes of the PDAC surfaceome, which reveals syndecan 1 (SDC1, also known as CD138) as a protein that is upregulated at the cell surface by KRAS*. Localization of SDC1 at the cell surface-where it regulates macropinocytosis, an essential metabolic pathway that fuels PDAC cell growth-is essential for disease maintenance and progression. Thus, our study forges a mechanistic link between KRAS* signalling and a targetable molecule driving nutrient salvage pathways in PDAC and validates oncogene-driven surfaceome annotation as a strategy to identify cancer-specific vulnerabilities.

Gender inequality, economic growth, and the intergenerational transmission of adverse health consequences at birth.

We estimate a gender differential in the intergenerational transmission of adverse birth outcomes. We link Taiwan birth certificates from 1978 to 2006 to create a sample of children born in the period 1999-2006 that includes information about their parents and their maternal grandmothers. We use maternal-sibling fixed effects to control for unobserved family-linked factors that may be correlated with birth outcomes across generations, and define adverse birth outcomes as small for gestational age. We find that when a mother is in the 5th percentile of birth weight for her gestational age, then her female children are 49-53% more likely to experience the same adverse birth outcome compared to other female children, while her male children are 27-32% more likely to experience this relative to other male children. We then investigate whether long-run improvements in local socio-economic conditions experienced by the child's family, as measured by intergenerational changes in town-level maternal education, affect the gender differential. We find no evidence that intergenerational improvements in socioeconomic conditions reduce the gender differential.

The Intergenerational Transmission of Low Birth Weight and Intrauterine Growth Restriction: A Large Cross-generational Cohort Study in Taiwan.

Objectives Our research provides evidence on the intergenerational fetal programming effect by examining associations in the low birth weight (LBW, birth weight <2500 g) and intrauterine growth restriction (IUGR) status between two adjacent generations from both the maternal and paternal sides. Methods Birth certificate data of the entire Taiwanese population are used to construct three-consecutive-generational samples. The final samples consist of the third-generation children born during 1999-2006 to at least one second-generation (G2) parent born during 1978-1985. Maternal and paternal samples are distinguished based on the gender of G2. We first fit the samples with linear probability models while including extensive explanatory variables to control for myriad confounding factors. We then include G2 sibling fixed effects to account for family-specific heterogeneity. Alternative explanations of sample selection, parents' assortative mating, and grandmothers' postnatal investment are examined. Results We find that significant intergenerational associations in LBW and IUGR only occur matrilineally. Children born to LBW mothers are 2.28 (95% CI, 0.71-3.85; p < 0.01) percentage points, corresponding to 36%, more likely to be LBW compared to children born to non-LBW mothers who are sisters. These associations cannot be explained by the above alternative explanations. Conclusions Under G2 sibling comparisons, children born to LBW (IUGR) mothers are more likely to be LBW (IUGR), but children born to LBW (IUGR) fathers are not. The findings suggest that maternal health is pertinent and that socio-economic interventions may not yield the desired outcomes within a short period of time.

The Short-Run and Long-Run Effects of Birth Weight: Evidence from Large Samples of Siblings and Twins in Taiwan.

In this paper, we assemble five large administrative data sets in Taiwan to investigate the short-run and long-run effects of birth weight. Comparing with previous studies, our results are more precisely estimated due to the large sample size. Using administrative data sets, the problems arising from self-reported samples are also mitigated. Moreover, we are able to examine both singletons by controlling sibling fixed effects and twins by controlling twin fixed effects. Our results show that an infant's birth weight has positive influence on health and education. Our twin fixed-effects estimates confirm the finding of a long-lasting, but diminishing in the longer run, effects of birth weight. Copyright © 2016 John Wiley & Sons, Ltd.

Parental age difference, educationally assortative mating and offspring count: evidence from a contemporary population in Taiwan.

Using contemporary population data from Taiwan, we examine the relationships between parental age difference, educationally assortative mating, income and offspring count. Controlling for women's reproductive value (measured by age at first birth), we find that an older husband is associated with fewer offspring, whereas a husband with similar or higher education is associated with more offspring. Concerning resources, we find that women's income is negatively associated with fertility and husband's income is positively associated with fertility among highly educated women. These results are consistent with the view that women compensate for trade-offs between education, income generation and childbearing by seeking mates with a higher status.

Parental Education and Child Health: Evidence from a Natural Experiment in Taiwan.

In 1968, the Taiwanese government extended compulsory education from six to nine years and opened over 150 new junior high schools at a differential rate among regions. Within each region, we exploit variations across cohorts in new junior high school openings to construct an instrument for schooling and employ it to estimate the causal effects of mother's or father's schooling on infant birth outcomes in the years 1978-1999. Parents' schooling does indeed cause favorable infant health outcomes. The increase in schooling associated with the reform saved almost 1 infant life in 1,000 live births. "The one social factor that researchers agree is consistently linked to longer lives in every country where it has been studied is education. It is more important than race; it obliterates any effects of income." Gina Kolata, "A Surprising Secret to Long Life: Stay in School,"New York Times, January 3, 2007, p. 1.

Do lower birth weight babies have lower grades? Twin fixed effect and instrumental variable method evidence from Taiwan.

By combining two unique Taiwanese datasets, this paper investigates how birth weight affects grades at age 15 years. To tackle the endogeneity problem caused by omitted variables, we first compare birth weight and grade variation within twins. We find that birth weight does increase grades but only when both twins weigh less than 3000g at birth, which indicates that the effect is non-linear, and when the weight difference between the twins is larger than 200g. Furthermore, twin fixed effect estimates are similar to the ordinary least squares (OLSs) ones. We then use the public health budget and the number of doctors in the county where the children were born as instrumental variables for the children's birth weight. We found that instrumental variable estimates are significant only for the less educated (<9 years) and young (<25 years) mothers. We conclude that the effect of birth weight is real and non-linear and its effect on less educated and young mothers is the most severe. Furthermore, the bias produced by OLS may not be large if the correct subgroup of the population has been identified.

Willingness to pay for weight-control treatment.

OBJECTIVES: To estimate willingness to pay (WTP) for alternative forms of weight-control treatment and evaluate how it varies with individual characteristics. METHODS: Contingent valuation (CV) survey of employed females in Taiwan using double-bounded dichotomous-choice question format and telephone interview. Statistical models include an estimated correction for sample-selection bias associated with respondents' interest in weight loss. RESULTS: Estimated WTP is strongly and positively associated with younger age, greater personal income, higher body weight, adverse personal weight perceptions, and greater peer pressure for weight control. There is a little evidence of sample-selection bias associated with the decision to lose weight. Estimated WTP for a weight-loss medicine is about US$ 12 per month, larger than estimated WTP for a low-calorie diet of about US$ 10 per month. CONCLUSIONS: WTP for weight-control treatment among women in Taiwan is significant and related to individual characteristics such as age, income, and perceptions about current and optimal weight.

Valuation of the economic benefits of human papillomavirus vaccine in Taiwan.

OBJECTIVES: The study aims to apply the contingent valuation method to elicit the willingness-to-pay (WTP), and measure the value of a statistic life (VSL), for human papillomavirus (HPV) vaccine in Taiwan. METHODS: A total of 512 questionnaires were completed on women aged 20 to 55 years with at least one daughter, during March through May 2007. The respondents' WTP for the vaccines was elicited by double-bounded binary-choice questions under two scenarios: one was to protect themselves from cervical cancer (CC) and the other was for their daughter(s). The WTP was modeled as a function of the respondents' knowledge score, attitudes toward CC and HPV vaccine, the vaccination outcome scenarios, and individual characteristics. A log-normal survival model was constructed and the maximum-likelihood method was used for estimation. RESULTS: The median regression-adjusted WTP was estimated at US$1098 to US$1233 (US$913-1004) for vaccinating the daughter (mother); and the VSL was estimated at approximately US$0.65 to US$4.09 (US$0.56-3.16) million for vaccinating the daughter (mother). CONCLUSIONS: The study results provided important evidences on the monetary value women placed on a HPV vaccine, and the differential benefits between vaccinating the women and their daughters.

Academic achievement of twins and singletons in early adulthood: Taiwanese cohort study.

OBJECTIVES: To examine the long term effects of low birth weight on academic achievements in twins and singletons and to determine whether the academic achievement of twins in early adulthood is inferior to that of singletons. DESIGN: Cohort study. SETTING: Taiwanese nationwide register of academic outcome. PARTICIPANTS: A cohort of 218 972 singletons and 1687 twins born in Taiwan, 1983-5. MAIN OUTCOME MEASURE: College attendance and test scores in the college joint entrance examinations. RESULTS: After adjustment for birth weight, gestational age, birth order, and sex and the sociodemographic characteristics of the parents, twins were found to have significantly lower mean test scores than singletons in Chinese, mathematics, and natural science, as well as a 2.2% lower probability of attending college. Low birthweight twins had an 8.5% lower probability of college attendance than normal weight twins, while low birthweight singletons had only a 3.2% lower probability. The negative effects of low birth weight on the test scores in English and mathematics were substantially greater for twins than for singletons. The twin pair analysis showed that the association between birth weight and academic achievement scores, which existed for opposite sex twin pairs, was not discernible for same sex twin pairs, indicating that birth weight might partly reflect other underlying genetic variations. CONCLUSIONS: These data support the proposition that twins perform less well academically than singletons. Low birth weight has a negative association with subsequent academic achievement in early adulthood, with the effect being stronger for twins than for singletons. The association between birth weight and academic performance might be partly attributable to genetic factors.