Comprehensive Characterization of Cancer Driver Genes and Mutations.

Identifying molecular cancer drivers is critical for precision oncology. Multiple advanced algorithms to identify drivers now exist, but systematic attempts to combine and optimize them on large datasets are few. We report a PanCancer and PanSoftware analysis spanning 9,423 tumor exomes (comprising all 33 of The Cancer Genome Atlas projects) and using 26 computational tools to catalog driver genes and mutations. We identify 299 driver genes with implications regarding their anatomical sites and cancer/cell types. Sequence- and structure-based analyses identified >3,400 putative missense driver mutations supported by multiple lines of evidence. Experimental validation confirmed 60%-85% of predicted mutations as likely drivers. We found that >300 MSI tumors are associated with high PD-1/PD-L1, and 57% of tumors analyzed harbor putative clinically actionable events. Our study represents the most comprehensive discovery of cancer genes and mutations to date and will serve as a blueprint for future biological and clinical endeavors.

Synergistically Engineering Grains and Grain Boundaries toward Li Dendrite-Free Li7La3Zr2O12.

Cation-doped cubic Li7La3Zr2O12 is regarded as a promising solid electrolyte for safe and energy-dense solid-state lithium batteries. However, it suffers from the formation of Li2CO3 and high electronic conductivity, which give rise to an unconformable Li/Li7La3Zr2O12 interface and lithium dendrites. Herein, composite AlF3-Li6.4La3Zr1.4Ta0.6O12 solid electrolytes were created based on thermal AlF3 decomposition and F/O displacement reactions under a high-temperature sintering process. When the AlF3 is thermally decomposed, it leaves Al2O3/AlF3 meliorating the grain boundaries and F- ions partially displacing O2- ions in the grains. Due to the higher electronegativity of F- in the grains and the grain-boundary modification, these AlF3-Li6.4La3Zr1.4Ta0.6O12 deliver optimized electronic conduction and chemical stability against the formation of Li2CO3. The Li/AlF3-Li6.4La3Zr1.4Ta0.6O12/Li cell exhibits a low interfacial resistance of ∼16 Ω cm2 and an ultrastable long-term cycling behavior for 800 h under a current density of 200 µA/cm2, leading to Li//LiCoO2 solid-state batteries with good rate performance and cycling stability.

Targeting tumour surface collage with hydrogel probe: a new strategy to enhance intraoperative imaging sensitivity and stability of bladder cancer.

PURPOSE: The incomplete resection of non-muscle invasive bladder cancer (NMIBC) augments the risk of disease recurrence. Imaging-guided surgery by molecular probes represents a pivotal strategy for mitigating postoperative recurrence. Traditional optical molecular probes, primarily composed of antibodies/peptides targeting tumour cells and fluorescent groups, are challenged by the high heterogeneity of NMIBC cells, leading to inadequate probe sensitivity. We have developed a collagen-adhesive probe (CA-P) to target the collagen within the tumour microenvironment, aiming to address the issue of insufficient imaging sensitivity. METHODS: The distribution characteristics of collagen in animal bladder cancer models and human bladder cancer tissues were explored. The synthesis and properties of CA-P were validated. In animal models, the imaging performance of CA-P was tested and compared with our previously reported near-infrared probe PLSWT7-DMI. The clinical translational potential of CA-P was assessed using human ex vivo bladder tissues. RESULTS: The distribution of collagen on the surface of tumour cells is distinct from its expression in normal urothelium. In vitro studies have demonstrated the ability of the CA-P to undergo a "sol-gel" transition upon interaction with collagen. In animal models and human ex vivo bladder specimens, CA-P exhibits superior imaging performance compared to PLSWT7-DMI. The sensitivity of this probe is 94.1%, with a specificity of 81%. CONCLUSION: CA-P demonstrates the capability to overcome tumour cell heterogeneity and enhance imaging sensitivity, exhibiting favorable imaging outcomes in preclinical models. These findings provide a theoretical basis for the application of CA-P in intraoperative navigation for NMIBC.

Sample size calculation for mixture model based on geometric average hazard ratio and its applications to nonproportional hazard.

With the advent of cancer immunotherapy, some special features including delayed treatment effect, cure rate, diminishing treatment effect and crossing survival are often observed in survival analysis. They violate the proportional hazard model assumption and pose a unique challenge for the conventional trial design and analysis strategies. Many methods like cure rate model have been developed based on mixture model to incorporate some of these features. In this work, we extend the mixture model to deal with multiple non-proportional patterns and develop its geometric average hazard ratio (gAHR) to quantify the treatment effect. We further derive a sample size and power formula based on the non-centrality parameter of the log-rank test and conduct a thorough analysis of the impact of each parameter on performance. Simulation studies showed a clear advantage of our new method over the proportional hazard based calculation across different non-proportional hazard scenarios. Moreover, the mixture modeling of two real trials demonstrates how to use the prior information on the survival distribution among patients with different biomarker and early efficacy results in practice. By comparison with a simulation-based design, the new method provided a more efficient way to compute the power and sample size with high accuracy of estimation. Overall, both theoretical derivation and empirical studies demonstrate the promise of the proposed method in powering future innovative trial designs.

Smoking-related cancer death among men and women in an ageing society (China 2020-2040): a population-based modelling study.

BACKGROUND: China is experiencing a postpeak smoking epidemic with accelerating population ageing. Understanding the impacts of these factors on the future cancer burden has widespread implications. METHODS: We developed predictive models to estimate smoking-related cancer deaths among men and women aged ≥35 years in China during 2020-2040. Data sources for model parameters included the United Nations World Population Prospects, China Death Surveillance Database, national adult tobacco surveys and the largest national survey of smoking and all causes of death to date. The main assumptions included stable sex-specific and age-specific cancer mortality rates and carcinogenic risks of smoking over time. RESULTS: In a base-case scenario of continuing trends in current smoking prevalence (men: 57.4%-50.5%; women: 2.6%-2.1% during 2002-2018), the smoking-related cancer mortality rate with population ageing during 2020-2040 would rise by 44.0% (from 337.2/100 000 to 485.6/100 000) among men and 52.8% (from 157.3/100 000 to 240.4/100 000) among women; over 20 years, there would be 8.6 million excess deaths (0.5 million more considering former smoking), and a total of 117.3 million smoking-attributable years of life lost (110.3 million (94.0%) in men; 54.1 million (46.1%) in working-age (35-64 years) adults). An inflection point may occur in 2030 if smoking prevalence were reduced to 20% (Healthy China 2030 goal), and 1.4 million deaths would be averted relative to the base-case scenario if the trend were maintained through 2040. CONCLUSIONS: Coordinated efforts are urgently needed to curtail a rising tide of cancer deaths in China, with intensified tobacco control being key.

High-Performance Ag2Se Film by a Microwave-Assisted Synthesis Method for Flexible Thermoelectric Generators.

Flexible Ag2Se thermoelectric (TE) films are promising for wearable applications near room temperature (RT). Herein, a Ag2Se film on a nylon membrane with high TE performance was fabricated by a facile method. First, Ag2Se powders were prepared by a microwave-assisted synthesis method using Ag nanowires as a template. Second, the Ag2Se powders were deposited onto nylon via vacuum filtration followed by hot pressing. Through modulating the Ag/Se molar ratio for synthesizing the Ag2Se powders, an optimized Ag2Se film demonstrates a high power factor of 1577.1 µW m-1 K-2 and good flexibility at RT. The flexibility of the Ag2Se film is mainly attributed to the flexible nylon membrane. In addition, a six-leg flexible TE generator (f-TEG) fabricated with the optimized Ag2Se film exhibits a maximum power density of 18.4 W m-2 at a temperature difference of 29 K near RT. This work provides a new solution to prepare high-TE-performance flexible Ag2Se films for f-TEGs.

Organic Fluorescent Probes for Monitoring Micro-Environments in Living Cells and Tissues.

As a vital parameter in living cells and tissues, the micro-environment is crucial for the living organisms. Significantly, organelles require proper micro-environment to achieve normal physiological processes, and the micro-environment in organelles can reflect the state of organelles in living cells. Moreover, some abnormal micro-environments in organelles are closely related to organelle dysfunction and disease development. So, visualizing and monitoring the variation of micro-environments in organelles is helpful for physiologists and pathologists to study the mechanisms of the relative diseases. Recently, a large variety of fluorescent probes was developed to study the micro-environments in living cells and tissues. However, the systematic and comprehensive reviews on the organelle micro-environment in living cells and tissues have rarely been published, which may hinder the research progress in the field of organic fluorescent probes. In this review, we will summarize the organic fluorescent probes for monitoring the microenvironment, such as viscosity, pH values, polarity, and temperature. Further, diverse organelles (mitochondria, lysosome, endoplasmic reticulum, cell membrane) about microenvironments will be displayed. In this process, the fluorescent probes about the "off-on" and ratiometric category (the diverse fluorescence emission) will be discussed. Moreover, the molecular designing, chemical synthesis, fluorescent mechanism, and the bio-applications of these organic fluorescent probes in cells and tissues will also be discussed. Significantly, the merits and defects of current microenvironment-sensitive probes are outlined and discussed, and the development tendency and challenges for this kind of probe are presented. In brief, this review mainly summarizes some typical examples and highlights the progress of organic fluorescent probes for monitoring micro-environments in living cells and tissues in recent research. We anticipate that this review will deepen the understanding of microenvironment in cells and tissues and facilitate the studies and development of physiology and pathology.

[Surgical Safety of Elderly Hospitalized Patients Stratified by Age in General Surgery].

Objective To compare the surgical safety of elderly hospitalized patients in different age groups undergoing general surgery,and provide references for preoperative evaluation and treatment decision-making.Methods The inpatients ≥ 60 years old in the department of general surgery were selected from a national multi-center survey conducted from January to June in 2015 and from January to June in 2016.The patient characteristics and postoperative outcomes were described,and the risk factors for adverse postoperative outcomes of patients in different age groups were explored.Results The elderly patients (≥75 years old) accounted for 17.33%.The non-elderly patient (< 75 years old) group and the elderly patient (≥75 years old) group had significant differences in the proportions of patients with three or more chronical diseases (13.18% vs.5.36%,P<0.001),emergency surgery (16.64% vs.7.62%,P<0.001),American Society of Anesthesiologists score≥3 (48.68% vs.27.28%,P<0.001),and postoperative return to the intensive care unit(33.64% vs.12.00%,P<0.001).The occurrence of postoperative infectious complications showed no significant difference between the two age groups (7.29% vs.6.40%,P=0.410),while severe complications differed between the two groups (6.51% vs.2.60%,P<0.001).Besides,emergency surgery was a common independent risk factor for the two age groups.Conclusions Advanced age is not a contraindication to surgery of elderly patients.With consideration to patient's physical conditions and available surgical resources,elderly patients can still benefit from surgery.

Nationwide gastric cancer prevention in China, 2021-2035: a decision analysis on effect, affordability and cost-effectiveness optimisation.

OBJECTIVE: To project future trajectories of the gastric cancer (GC) burden in China under different scenarios of GC prevention and identify strategies to improve affordability and cost-effectiveness. DESIGN: Using a cohort of Chinese men and women born during 1951-1980, we assumed that different prevention strategies were conducted, including eradication of Helicobacter pylori (Hp) and endoscopy screening (one-time, annual, biennial, triennial or stratified according to personal risk). We performed a literature search to identify up-to-date data and populate a Markov model to project the number of new GC cases and deaths during 2021-2035, as well as resource requirements and quality-adjusted life-years (QALYs). We examined the impacts of general (among the whole population) and targeted (high-risk population) prevention. RESULTS: During 2021-2035, 10.0 million new GC cases and 5.6 million GC deaths would occur, with 7.6%-35.5% and 6.9%-44.5%, respectively, being avoidable through various prevention strategies. Relative to the status quo, Hp eradication was a cost-saving strategy. General annual screening dominated other screening strategies, but cost more than CNY 70 000 per QALY gained (willingness-to-pay) compared with Hp eradication. Among endoscopy strategies, targeted screening resulted in 44%-49% lower cost per QALY gained over the status quo than general screening. Among high-risk population, tailoring the screening frequency according to personal risk could reduce endoscopy-related resources by 22% compared with biennial screening and by 55% compared with annual screening, CONCLUSION: Our findings provide important input for future decision-making and investment, highlighting the need and feasibility for China to include GC prevention in its national health plans.

Integrated transcriptomic-genomic tool Texomer profiles cancer tissues.

Profiling of both the genome and the transcriptome promises a comprehensive, functional readout of a tissue sample, yet analytical approaches are required to translate the increased data dimensionality, heterogeneity and complexity into patient benefits. We developed a statistical approach called Texomer ( https://github.com/KChen-lab/Texomer ) that performs allele-specific, tumor-deconvoluted transcriptome-exome integration of autologous bulk whole-exome and transcriptome sequencing data. Texomer results in substantially improved accuracy in sample categorization and functional variant prioritization.

Generating real-world evidence compatible with evidence from randomized controlled trials: a novel observational study design applicable to surgical transfusion research.

BACKGROUND: Numerous observational studies have revealed an increased risk of death and complications with transfusion, but this observation has not been confirmed in randomized controlled trials (RCTs). The "transfusion kills patients" paradox persists in real-world observational studies despite application of analytic methods such as propensity-score matching. We propose a new design to address this long-term existing issue, which if left unresolved, will be deleterious to the healthy generation of evidence that supports optimized transfusion practice. METHODS: In the new design, we stress three aspects for reconciling observational studies and RCTs on transfusion safety: (1) re-definition of the study population according to a stable hemoglobin range (gray zone of transfusion decision; 7.5-9.5 g/dL in this study); (2) selection of comparison groups according to a trigger value (last hemoglobin measurement before transfusion; nadir during hospital stay for control); (3) dealing with patient heterogeneity according to standardized mean difference (SMD) values. We applied the new design to hospitalized older patients (aged ≥60 years) undergoing general surgery at four academic/teaching hospitals. Four datasets were analyzed: a base population before (Base Match-) and after (Base Match+) propensity-score matching to simulate previous observational studies; a study population before (Study Match-) and after (Study Match+) propensity-score matching to demonstrate effects of our design. RESULTS: Of 6141 older patients, 662 (10.78%) were transfused and showed high heterogeneity compared with those not receiving transfusion, particularly regarding preoperative hemoglobin (mean: 11.0 vs. 13.5 g/dL) and intraoperative bleeding (≥500 mL: 37.9% vs. 2.1%). Patient heterogeneity was reduced with the new design; SMD of the two variables was reduced from approximately 100% (Base Match-) to 0% (Study Match+). Transfusion was related to a higher risk of death and complications in Base Match- (odds ratio [OR], 95% confidence interval [CI]: 2.68, 1.86-3.86) and Base Match+ (2.24, 1.43-3.49), but not in Study Match- (0.77, 0.32-1.86) or Study Match+ (0.66, 0.23-1.89). CONCLUSIONS: We show how choice of study population and analysis could affect real-world study findings. Our results following the new design are in accordance with relevant RCTs, highlighting its value in accelerating the pace of transfusion evidence generation and generalization.

[Patterns of Perioperative Blood Transfusion in Patients with Blood Loss during Major Cardiac Surgery].

Objective To investigate the patterns of perioperative blood transfusion in patients with blood loss during major cardiac surgery,so as to provide data reference for rational and standardized blood use.Methods The adult patients(aged 18 years or above)who underwent vascular surgery,coronary artery bypass grafting surgery,heart valve surgery or surgery for congenital heart disease in a national multicenter(four large hospitals)survey in China,2015-2016 were included in this study.We described their baseline characteristics,postoperative outcomes,and in particular,bleeding and patterns of perioperative blood transfusion(autologous and allogeneic,the latter including red blood cells,plasma,and platelet,or a combination of these components).Results Autologous blood transfusion in operation accounted for the highest proportion(58.84%)in patients undergoing heart valve surgery.The patients undergoing vascular surgery had the largest autologous blood transfusion volume(722 ml)and the highest intraoperative transfusion proportion of allogeneic blood(53.28%),especially that of platelet(39.34%).Compared with the transfusion of red blood cells,the transfusion of other blood components showed concentrated time distribution,and the proportion of plasma transfusion was the highest one day post operation.With the increase in bleeding volume,combined transfusion presented increased proportion and became the dominant transfusion pattern.Conclusions The blood transfusion patterns varied significantly depending on different types of cardiac surgery,different perioperative stages,and different bleeding volumes.It is necessary to formulate the targeted transfusion practice scheme on the basis of understanding the current situation,so as to make better use of blood resources and improve the safety of transfusion.

Air-Stable Conductive Polymer Ink for Printed Wearable Micro-Supercapacitors.

Printed electronics are expected to facilitate the widespread distributed wearable electronics in the era of the Internet of things. However, developing cheap and stable electrode inks remains a significant challenge in the printed electronics industry and academic community. Here, overcoming the weak hydrophilicity of polyaniline, a low-cost, easy-fabricating, and air-stable conducting polymer (CP) ink is devised through a facile assemble-disperse strategy delivering a high conductivity in the order of 10-2 S cm-1 along with a remarkable specific capacitance of 386.9 F g-1 at 0.5 A g-1 (dehydrated state). The additive-free CP ink is directly employed to print wearable micro-supercapacitors (MSCs) via the spray-coating method, which deliver a high areal capacitance (96.6 mF cm-2 ) and volumetric capacitance (26.0 F cm-3 ), outperforming most state-of-the-art CP-based supercapacitors. This work paves a new approach for achieving scalable MSCs, thus rendering a cost-effective, environmentally friendly, and pervasive energy solution for next-generation distributed electronics.

Optimizing the timing of diagnostic testing after positive findings in lung cancer screening: a proof of concept radiomics study.

BACKGROUND: The timeliness of diagnostic testing after positive screening remains suboptimal because of limited evidence and methodology, leading to delayed diagnosis of lung cancer and over-examination. We propose a radiomics approach to assist with planning of the diagnostic testing interval in lung cancer screening. METHODS: From an institute-based lung cancer screening cohort, we retrospectively selected 92 patients with pulmonary nodules with diameters ≥ 3 mm at baseline (61 confirmed as lung cancer by histopathology; 31 confirmed cancer-free). Four groups of region-of-interest-based radiomic features (n = 310) were extracted for quantitative characterization of the nodules, and eight features were proven to be predictive of cancer diagnosis, noise-robust, phenotype-related, and non-redundant. A radiomics biomarker was then built with the random survival forest method. The patients with nodules were divided into low-, middle- and high-risk subgroups by two biomarker cutoffs that optimized time-dependent sensitivity and specificity for decisions about diagnostic workup within 3 months and about repeat screening after 12 months, respectively. A radiomics-based follow-up schedule was then proposed. Its performance was visually assessed with a time-to-diagnosis plot and benchmarked against lung RADS and four other guideline protocols. RESULTS: The radiomics biomarker had a high time-dependent area under the curve value (95% CI) for predicting lung cancer diagnosis within 12 months; training: 0.928 (0.844, 0.972), test: 0.888 (0.766, 0.975); the performance was robust in extensive cross-validations. The time-to-diagnosis distributions differed significantly between the three patient subgroups, p < 0.001: 96.2% of high-risk patients (n = 26) were diagnosed within 10 months after baseline screen, whereas 95.8% of low-risk patients (n = 24) remained cancer-free by the end of the study. Compared with the five existing protocols, the proposed follow-up schedule performed best at securing timely lung cancer diagnosis (delayed diagnosis rate: < 5%) and at sparing patients with cancer-free nodules from unnecessary repeat screenings and examinations (false recommendation rate: 0%). CONCLUSIONS: Timely management of screening-detected pulmonary nodules can be substantially improved with a radiomics approach. This proof-of-concept study's results should be further validated in large programs.

Prognostic role of parafibromin staining and CDC73 mutation in patients with parathyroid carcinoma: A systematic review and meta-analysis based on individual patient data.

BACKGROUND AND OBJECTIVE: Parathyroid carcinoma (PC) is a rare malignant neoplasm with a relatively poor prognosis. The loss of parafibromin expression or the presence of CDC73 mutation has been found to be remarkably associated with malignancy in parathyroid tumours. However, the prognostic role of them in PC has not yet been shown due to sampling limitations. We conducted a systematic review and meta-analysis based on individual patient data to clarify the performance of parafibromin immunohistochemical staining and CDC73 gene sequencing in predicting outcomes for patients PC. METHODS: Published studies from PubMed/MEDLINE, EMBASE, Cochrane and Scopus Databases were searched using the terms 'parafibromin', 'CDC73', 'HRPT2' and 'parathyroid' to identify eligible studies. From the included studies, the survival data of patients with PC were extracted, and a Cox proportional hazards model was used to assess hazard ratio (HR) for disease-free survival (DFS) and overall survival (OS). RESULTS: A total of 193 patients from 9 studies were included in this survival analysis. Negative immunohistochemical staining of parafibromin was shown to be a risk factor for recurrence/metastasis (HR 2.73, P = .002) and death (HR 2.54, P = .004). Patient age ≥ 50 years was significantly related to lower OS (HR 2.37, P = .004) but not to DFS. CDC73 mutation was not statistically related to DFS or OS. CONCLUSIONS: Negative parafibromin staining indicated a higher risk of recurrence/metastasis and mortality. The immunohistochemical staining of parafibromin seems to be more promising in predicting outcomes for patients with PC than the sequencing of CDC73.

Population-based projections of blood supply and demand, China, 2017-2036.

OBJECTIVE: To estimate the long-term effect of the changing demography in China on blood supply and demand. METHODS: We developed a predictive model to estimate blood supply and demand during 2017-2036 in mainland China and in 31 province-level regions. Model parameters were obtained from World Population Prospects, China statistical yearbook 2016, China's report on blood safety and records from a large tertiary hospital. Our main assumptions were stable age-specific per capita blood supply and demand over time. FINDINGS: We estimated that the change in demographic structure between 2016 (baseline year) and 2036 would result in a 16.0% decrease in blood supply (from 43.2 million units of 200 mL to 36.3 million units) and a 33.1% increase in demand (from 43.2 million units to 57.5 million units). In 2036, there would be an estimated shortage of 21.2 million units. An annual increase in supply between 0.9% and 1.8% is required to maintain a balance in blood supply and demand. This increase is not enough for every region as regional differences will increase, e.g. a blood demand/supply ratio ≥ 1.45 by 2036 is predicted in regions with large populations older than 65 years. Sensitivity analyses showed that increasing donations by 4.0% annually by people aged 18-34 years or decreasing the overall blood discard rate from 5.0% to 2.0% would not offset but help reduce the blood shortage. CONCLUSION: Multidimensional strategies and tailored, coordinated actions are needed to deal with growing pressures on blood services because of China's ageing population.

Clinical features of pulmonary cryptococcosis in thin-section CT in immunocompetent and non-AIDS immunocompromised patients.

RATIONAL AND OBJECTIVES: To compare thin-section computed tomography (CT) features of pulmonary cryptococcosis (PC) in immunocompetent and non-AIDS immunocompromised patients. MATERIALS AND METHODS: We retrospectively reviewed CT findings of 18 immunocompetent and 24 non-AIDS immunocompromised patients with clinically proven PC. Different patterns of pulmonary abnormalities between the two groups of patients were compared by Fisher's exact test. RESULTS: Pulmonary nodules were present in 37 of the 42 patients. Masses were detected in 16 patients and consolidation in 9. There were 12 patients with a solitary nodule or mass. Masses were associated with nodules in 12 patients. Consolidation was associated with nodules/masses in nine patients. The nodules/masses were associated with cavitations in 13 patients. Margination of nodules/masses was well defined in nine patients and ill-defined in 33. The abnormalities were predominantly distributed in the peripheral region of the lung (n = 29, 69.0%). The presence of cavitations in nodules/masses was significantly more frequent in non-AIDS immunocompromised than in immunocompetent patients (P = 0.001). CONCLUSIONS: The most common thin-section CT feature of PC was pulmonary nodules/masses, which were ill-defined and located peripherally. Cavitations within nodules/masses were more commonly found in non-AIDS immunocompromised patients. PC should be considered in the differential diagnosis of pulmonary nodules/masses.

Ultraspiracle-independent anti-apoptotic function of ecdysone receptors is required for the survival of larval peptidergic neurons via suppression of grim expression in Drosophila melanogaster.

In Drosophila melanogaster a significant number of heterogenous larval neurons in the central nervous system undergo metamorphosis-associated programmed cell death, termed metamorphoptosis. Interestingly distinct groups of doomed larval neurons are eliminated at different metamorphic phases. Although ecdysone hormonal signaling via nuclear ecdysone receptors (EcRs) is known to orchestrate the neuronal metamorphoptosis, little is known about how this signaling controls such diverse neuronal responses. Crustacean cardioactive peptide (CCAP)-producing neurons in the ventral nerve cord are developmentally programmed to die shortly after adult emergence. In this study, we show that disruption of endogenous EcR function by ectopic expression of dominant negative forms of EcRs (EcRDN) causes premature death of larval CCAP neurons in a caspase-dependent manner. This event is rescued by co-expression of individual EcR isoforms. Furthermore, larval CCAP neurons are largely normal in ecr mutants lacking either EcR-A or EcR-B isoforms, suggesting that EcR isoforms redundantly function to protect larval CCAP neurons. Of surprise, a role of Ultraspiracle (Usp), a canonical partner of EcR, is dispensable in the protection of CCAP neurons, whereas both EcR and Usp are required for inducing metamorphoptosis of vCrz neurons shortly after prepupal formation. As a downstream, grim is an essential cell death gene for the EcRDN-mediated CCAP neuronal death, while either hid or rpr function is dispensable. Together, our results suggest that Usp-independent EcR actions protect CCAP neurons from their premature death by repressing grim expression until their normally scheduled apoptosis at post-emergence. Our studies highlight two opposite roles played by EcR function for metamorphoptosis of two different peptidergic neuronal groups, proapoptotic (vCrz) versus antiapoptotic (CCAP), and propose that distinct death timings of doomed larval neurons are determined by differential signaling mechanisms involving EcR.

Two-factor specification of apoptosis: TGF-ß signaling acts cooperatively with ecdysone signaling to induce cell- and stage-specific apoptosis of larval neurons during metamorphosis in Drosophila melanogaster.

Developmentally regulated programmed cell death (PCD) is one of the key cellular events for precise controlling of neuronal population during postembryonic development of the central nervous system. Previously we have shown that a group of corazonin-producing peptidergic neurons (vCrz) undergo apoptosis in response to ecdysone signaling via ecdysone receptor (EcR)-B isoforms and Ultraspiracle during early phase of metamorphosis. Further utilizing genetic, transgenic, and mosaic analyses, we have found that TGF-ß signaling mediated by a glia-produced ligand, Myoglianin, type-I receptor Baboon (particularly Babo-A isoform) and dSmad2, is also required autonomously for PCD of the vCrz neurons. Our studies show that TGF-ß signaling is not acting epistatically to EcR or vice versa. We also show that ectopic expression of a constitutively active phosphomimetic form of dSmad2 (dSmad2PM) is capable of inducing premature death of vCrz neurons in larva but not other larval neurons. Intriguingly, the dSmad2PM-mediated killing is completely suppressed by coexpression of a dominant-negative form of EcR (EcRDN), suggesting that EcR function is required for the proapoptotic dSmad2PM function. Based on these data, we suggest that TGF-ß and ecdysone signaling pathways act cooperatively to induce vCrz neuronal PCD. We propose that this type of two-factor authentication is a key developmental strategy to ensure the timely PCD of specific larval neurons during metamorphosis.