The study was designed to evaluate the relationship between serum progesterone (P4) response after hCG administration and the number of oocytes retrieved and the embryo quality in fresh IVF cycles.
We conducted a retrospective cohort study of women aged 24–43 years who underwent first fresh IVF cycle from 2011 to 2013 at a single practice. We compared the post-hCG serum P4 level with values on the day of hCG trigger. Patients were analyzed in long and short protocols independently. In addition, patients were stratified by post-hCG P4 response. Number of oocytes retrieved and embryo quality were the primary outcomes of interest. Ordinary least square regression models and logistic regression analysis models were created to identify predictive factors associated with embryological outcomes while adjusting for potential confounders.
Among the 2,978 IVF cycles, 2,484 patients were in long protocols, and 494 patients were in short protocols. After adjusting for patient age, rFSH duration, and basal FSH levels, the associations between P4 response after hCG administration and number of oocytes retrieved (P < 0.001) remained statistically significant in both long and short protocols. Additionally, mature oocyte rate, fertilization rate, good quality embryo rate, pregnancy rate and implantation rate were not significantly associated with the P4 increase when adjusting for the same factors. However, pregnancy rate and implantation rate from frozen-thawed cycles increased gradually across the seven groups.
Post-hCG P4 levels were positively associated with the number of oocytes retrieved, but did not affect oocyte or embryo quality. Our study suggests that the change in the post-hCG P4 level is another parameter that can be used by clinicians to assess the number of oocytes retrieved, and may further to estimate the pregnancy rate and live birth rate indirectly.
Progesterone; HCG; Oocyte number; Embryo quality
Background: Despite the large volume of research dedicated to health-related behavior change, chronic disease costs continue to rise, thus creating a major public health burden. Health literacy, the ability to seek, understand, and utilize health information, has been identified as an important factor in the course of chronic conditions. Little research has been conducted on the relationship between health literacy and health-related behaviors and health status in elderly Chinese. The aim of this study was to elucidate the relationship between health literacy and health-related behaviors and health status in China. Methods: The subjects enrolled in this study were selected based on a stratified cluster random sampling design. Information involving >4500 older adults in 44 pension institutions in Urumqi, Changji, Karamay, and Shihezi of Xinjiang between September 2011 and June 2012 was collected. The Chinese Citizen Health Literacy Questionnaire (China Health Education Centre, 2008) and a Scale of the General Status were administered and the information was obtained through face-to-face inquiries by investigators. A total of 1452 respondents met the inclusion criteria. A total of 1452 questionnaires were issued and the valid response rate was 96.14% (1396 of 1452). Factors affecting health literacy and the relationship to health literacy were identified by one-way ANOVA and a multiple linear regression model. Results: The average health literacy level of the elderly in nursing homes was relatively low (71.74 ± 28.35 points). There were significant differences in the health literacy score among the factors of age, gender, race, education level, household income, marital conditions, and former occupation (p < 0.001). The health literacy score was significantly associated with smoking, drinking, physical exercise, and health examination (p < 0.001). The elderly with higher health literacy scores were significantly less likely to have risky behaviors (smoking, regular drinking, and lack of physical exercise), and in turn significantly more likely to undergo health examinations regularly, report good self-rated health, and significantly more likely to access sufficient health information from multiple sources (p < 0.001). No differences were noted between the health literacy score and BMI (p > 0.05). Multiple linear regression analysis showed that the independent influencing factors of health literacy included education level, race, former occupation, household income, age, physical exercise, health examination, smoking, and health information access (p < 0.001). Conclusions: Health literacy was significantly associated with health-related behaviors in elderly Chinese. Further longitudinal studies are needed to help confirm that improving health literacy in the elderly may be effective in changing health-related behaviors. To reduce risky habits, educational interventions to improve health literacy should be simultaneously conducted in health promotion work.
health literacy; health-related behaviors; health status; nursing homes; relationship
Metabolic syndrome (MetS) is an important risk factor for cerebral ischemic stroke, yet previous studies on the relationship between MetS or its components and acute cerebral infarction have been inconsistent. This study aims to evaluate the effects of MetS and its components on the short-term prognosis of patients with acute ischemic stroke.
Subjects with ischemic stroke of <7-day duration (530 cases) were enrolled. MetS was defined based on the modified criteria of the International Diabetes Federation and the American Heart Association/National Heart, Lung, and Blood Institute. Demographic data, vascular risk factors, National Institutes of Health Stroke Scale score, the results of physical, laboratory and imaging examinations and clinical outcomes at 30 and 90 days were recorded. Using univariate analysis, we compared different baseline characteristics between patients with MetS and those without MetS. Further, we assessed MetS and its 5 components on the contribution to short-term prognosis of ischemic stroke with multiple logistic regression models after adjusting for age and sex.
The prevalence of MetS among the patients with acute ischemic stroke in the study is 58.3 %, with more in females (70.3 %) than in males (49.7 %, p < 0.001). As expected, among the MetS components, elevated waist circumference, elevated triglyceride, high fasting blood glucose and low high density lipoprotein cholesterol (HDL-C) were significantly more prevalent in patients with MetS than those without MetS (all p < 0.001). There was no correlation between MetS itself and the short-term prognosis of acute ischemic stroke. Only hyperglycemia in the serum was shown to have impact on poor functional outcomes in 30 and 90 days after the onset of stroke.
The occurrence of MetS among patients with acute ischemic stroke in our study is 58.3 %. MetS itself may not be predictive for the short-term prognosis of patients, while hyperglycemia is a significant predictor for poor functional outcomes in our study.
Metabolic syndrome; Acute ischemic stroke; Hyperglycemia; Prognosis
Congenital lipomatous asymmetric overgrowth of the trunk, lymphatic, capillary, venous, and combined-type vascular malformations, epidermal nevi, skeletal and spinal anomalies (CLOVES) syndrome, a segmental overgrowth syndrome, is caused by post zygotic somatic mutations in PIK3CA, a gene involved in the receptor tyrosine kinase phosphatidylinositol 3-kinase (PI3)-AKT growth-signaling pathway. Prenatal ultrasound findings of lymphovascular malformations, segmental overgrowth and skeletal defects can raise suspicion for CLOVES syndrome, but molecular confirmation of PIK3CA mutations on prenatally obtained samples is challenging because of somatic mosaicism. We detected a mosaic disease-causing mutation in PIK3CA by sequencing of DNA extracted from cultured amniotic cells, but not from DNA directly prepared from an amniotic fluid sample in a fetus with prenatally suspected CLOVES syndrome. The infant was born prematurely and displayed severe lymphovascular malformations and segmental overgrowth consistent with a clinical diagnosis of CLOVES syndrome; he passed away at 29 days of life. We discuss the complexities and limitations of genetic testing for somatic mosaic mutations in the prenatal period and highlight the potential need for multiple approaches to arrive at a molecular diagnosis.
somatic overgrowth; prenatal diagnosis; mosaicism; vascular anomalies; lipomatous malformation
In the U.S., marijuana is the most commonly used illicit drug. Its prevalence is growing, particularly among young adults. Behavioral economic indices of the relative reinforcing efficacy (RRE) of substances have been used to examine the appeal of licit (e.g., alcohol) and illicit (e.g., heroin) drugs. The present study is the first to use an experimental, simulated purchasing task to examine the RRE of marijuana. Young-adult (M age = 21.64 years) recreational marijuana users (N = 59) completed a computerized marijuana purchasing task designed to generate demand curves and the related RRE indices (e.g., intensity of demand - purchases at lowest price; Omax - max. spent on marijuana; Pmax - price at which marijuana expenditure is max). Participants “purchased” high-grade marijuana across 16 escalating prices that ranged from $0/free to $160/joint. They also provided 2-weeks of real-time, ecological momentary assessment reports on their marijuana use. The purchasing task generated multiple RRE indices. Consistent with research on other substances, the demand for marijuana was inelastic at lower prices but became elastic at higher prices, suggesting that increases in the price of marijuana could lessen its use. In regression analyses, the intensity of demand, Omax and Pmax, and elasticity each accounted for significant variance in real-time marijuana use. These results provide support for the validity of a simulated marijuana purchasing task to examine its reinforcing efficacy. This study highlights the value of applying a behavioral economic framework to young-adult marijuana use and has implications for prevention, treatment, and policies to regulate marijuana use.
marijuana use; simulated purchasing task; behavioral economics; demand curve for marijuana; relative reinforcement efficacy (RRE); ecological momentary assessment
Bone marrow mononuclear cells (BMMNCs) are important for angiogenesis after stroke. We investigated the effects of BMMNCs on cognitive function, angiogenesis, and the vascular endothelial growth factor (VEGF)-VEGF receptor 2 (VEGFR2) signaling pathway in a rat model of vascular dementia. We transplanted BMMNCs into rats that had undergone permanent bilateral occlusion of the common carotid arteries (2VO) and observed their migration in vivo. On day 28, we assessed cognitive function with the Morris Water Maze test and examined vascular density and white matter damage within the corpus striatum by staining with fluorescein lycopersicon esculentum (tomato) lectin or Luxol fast blue. We evaluated expression of VEGF, rapidly accelerated fibrosarcoma 1 (Raf1), and extracellular-signal-regulated kinases 1 and 2 (ERK1/2) in the ischemic hemisphere by Western blot analysis on day 7 after cell transplantation. Contribution of the VEGF-VEGFR2 signaling pathway was confirmed by using VEGFR2 inhibitor SU5416. BMMNCs penetrated the blood-brain barrier and reached the ischemic cortex and white matter or incorporated into vascular walls of 2VO rats. BMMNC-treated 2VO rats had better learning and memory, higher vascular density, and less white matter damage than did vehicle-treated rats. The beneficial effects of BMMNCs were abolished by pretreatment of rats with SU5416. Protein expression of VEGF and phosphorylated Raf1 and ERK1/2 was also significantly increased by BMMNC treatment, but this upregulation was reversed by SU5416. BMMNCs can enhance angiogenesis, reduce white matter damage, and promote cognitive recovery in 2VO rats. The angiogenic effect may result from upregulation of the VEGF-VEGFR2 signaling pathway.
angiogenesis; bone marrow mononuclear cells; cell transplantation; vascular dementia; VEGF-VEGFR2 signaling pathway
Our previous work showed that chronic activation of the membrane-bound estrogen receptor GPR30/GPER significantly lowers blood pressure in ovariectomized hypertensive mRen2.Lewis female rats which may, in part, reflect direct vasodilatory actions. The current study assessed the hypothesis that cyclic adenosine monophosphate (cAMP) signaling contributes to GPER-mediated vasorelaxation. In mesenteric resistance arteries from intact Lewis females, relaxation to 17-β-estradiol (E2; 47±3% of phenylephrine contraction vs. vehicle 89±2%, P<0.001) or G-1 (44±8%, P<0.001) was blunted to a similar extent by denuding (P<0.001) or the nitric oxide synthase inhibitor L-NAME (P<0.001). In contrast, the cyclooxygenase inhibitor indomethacin did not alter vasodilation (P>0.05). The cAMP analogue Rp-cAMPS partially attenuated vasodilation (65±7%, P<0.001), while the combination of L-NAME and Rp-cAMPS exhibited additive effects to effectively abolish vasorelaxation (P>0.05 vs. vehicle). Pretreatment of endothelium-intact vessels with the adenylyl cyclase inhibitor SQ (63±6%) or the guanylyl cyclase inhibitor ODQ (62±9%) both partially inhibited the response to G-1 (P<0.01), while pretreatment with the both inhibitors completely abolished vasorelaxation (P>0.05 vs. vehicle). In denuded vessels only SQ reduced the response (88±3%, P<0.001). Moreover, G-1 significantly increased intracellular cAMP levels in cultured mesenteric smooth muscle cells (P<0.05). We conclude that GPER-dependent vasorelaxation apparently involves both endothelial release of nitric oxide which activates guanylyl cyclase and smooth muscle cell activation of adenylyl cyclase. Downstream production of cyclic nucleotides and stimulation of protein kinases may phosphorylate proteins to promote vascular smooth muscle cell relaxation. The ability of GPER to initiate these signaling pathways may contribute to the beneficial vascular effects of estrogen.
GPER; GPR30; estrogen; cAMP; vasodilation; G proteins
inhibitor of apoptosis protein 1 and 2 (cIAP1/2) and X-linked
inhibitor of apoptosis protein (XIAP) are key apoptosis regulators
and promising new cancer therapeutic targets. This study describes
a set of non-peptide, small-molecule Smac (second mitochondria-derived
activator of caspases) mimetics that are selective inhibitors of cIAP1/2
over XIAP. The most potent and most selective compounds bind to cIAP1/2
with affinities in the low nanomolar range and show >1,000-fold
for cIAP1 over XIAP. These selective cIAP inhibitors effectively induce
degradation of the cIAP1 protein in cancer cells at low nanomolar
concentrations and do not antagonize XIAP in a cell-free functional
assay. They potently inhibit cell growth and effectively induce apoptosis
at low nanomolar concentrations in cancer cells with a mechanism of
action similar to that of other known Smac mimetics. Our study shows
that binding of Smac mimetics to XIAP BIR3 is not required for effective
induction of apoptosis in tumor cells by Smac mimetics. These potent
and highly selective cIAP1/2 inhibitors are powerful tools in the
investigation of the role of these IAP proteins in the regulation
of apoptosis and other cellular processes.
Cardiogenesis requires proper specification, proliferation, and differentiation of cardiac progenitor cells (CPCs). The differentiation of CPCs to specific cardiac cell types is likely guided by a comprehensive network comprised of cardiac transcription factors and epigenetic complexes. In this review, we describe how the ATP-dependent chromatin remodeling SWI/SNF complexes work synergistically with transcription and epigenetic factors to direct specific cardiac gene expression during CPC differentiation. Furthermore, we discuss how SWI/SNF may prime chromatin for cardiac gene expression at a genome-wide level. A detailed understanding of SWI/SNF-mediated CPC differentiation will provide important insight into the etiology of cardica defects and help design novel therapies for heart disease.
Amyloid β peptides
form fibrils that are commonly assumed to have a dry, homogeneous,
and static internal structure. To examine these assumptions, fibrils
under various conditions and different ages have been examined with
multidimensional infrared spectroscopy. Each peptide in the fibril
had a 13C=18O label in the backbone of
one residue to disinguish the amide I′ absorption due to that
residue from the amide I′ absorption of other residues. Fibrils
examined soon after they formed, and reexamined after 1 year in the
dry state, exhibited spectral changes confirming that structurally
significant water molecules were present in the freshly formed fibrils.
Results from fibrils incubated in solution for 4 years indicate that
water molecules remained trapped within fibrils and mobile over the
4 year time span. These water molecules are structurally significant
because they perturb the parallel β-sheet hydrogen bonding pattern
at frequent intervals and at multiple points within individual fibrils,
creating structural heterogeneity along the length of a fibril. These
results show that the interface between β-sheets in an amyloid
fibril is not a “dry zipper”, and that the internal
structure of a fibril evolves while it remains in a fibrillar state.
These features, water trapping, structural heterogeneity, and structural
evolution within a fibril over time, must be accommodated in models
of amyloid fibril structure and formation.
Stable isotopes; 18O; 13C; spectral crosspeaks; linear excitons; ultrafast vibrational laser spectroscopy; 2D infrared photon echo experiment
We previously reported the discovery of a class of spirooxindoles as potent and selective small-molecule inhibitors of the MDM2-p53 interaction (MDM2 inhibitors). We report herein our efforts to improve their pharmacokinetic properties and in vivo antitumor activity. Our efforts led to the identification of 9 (MI-888) as a potent MDM2 inhibitor (Ki = 0.44 nM) with a superior pharmacokinetic profile and enhanced in vivo efficacy. Compound 9 is capable of achieving rapid, complete, and durable tumor regression in two types of xenograft models of human cancer with oral administration and represents the most potent and efficacious MDM2 inhibitor reported to date.
Bcl-2 and Bcl-xL are critical regulators of apoptosis that are overexpressed in a variety of human cancers and pharmacological inhibition of Bcl-2 and Bcl-xL represents a promising strategy for cancer treatment. Using a structure-based design approach, we have designed BM-1197 as a potent and efficacious dual inhibitor of Bcl-2 and Bcl-xL. BM-1197 binds to Bcl-2 and Bcl-xL proteins with Ki values less than 1 nM and shows >1,000-fold selectivity over Mcl-1. Mechanistic studies performed in the Mcl-1 knockout mouse embryonic fibroblast (MEF) cells revealed that BM-1197 potently disassociates the heterodimeric interactions between anti-apoptotic and pro-apoptotic Bcl-2 family proteins, concomitant with conformational changes in Bax protein, loss of mitochondrial membrane potential and subsequent cytochrome c release to the cytosol, leading to activation of the caspase cascade and apoptosis. BM-1197 exerts potent growth-inhibitory activity in 7 of 12 small cell lung cancer cell lines tested and induces mechanism-based apoptotic cell death. When intravenously administered at daily or weekly in H146 and H1963 small-cell lung cancer xenograft models, it achieves complete and long-term tumor regression. Consistent with its targeting of Bcl-xL, BM-1197 causes transit platelet reduction in mice. Collectively, our data indicate that BM-1197 is a promising dual Bcl-2/Bcl-xL inhibitor which warrants further investigation as a new anticancer drug.
We have designed, synthesized and evaluated a series of new compounds based upon our previously reported bivalent Smac mimetics. This led to the identification of compound 12 (SM-1200), which binds to XIAP, cIAP1 and cIAP2 with Ki values of 0.5 nM, 3.7 nM and 5.4 nM, respectively, inhibits cell growth in the MDA-MB-231 breast cancer and SK-OV-3 ovarian cancer cell lines with IC50 values of 11.0 nM and 28.2 nM, respectively. Compound 12 has a much improved pharmacokinetic profile over our previously reported bivalent Smac mimetics and is highly effective in induction of rapid and durable tumor regression in the MDA-MB-231 xenograft model. These data indicate that compound 12 is a promising Smac mimetic and warrants extensive evaluation as a potential candidate for clinical development.
Small-molecule inhibitors that block the MDM2-p53 protein-protein interaction (MDM2 inhibitors) are being intensely pursued as a new therapeutic strategy for cancer treatment. We previously published a series of spirooxindole-containing compounds as a new class of MDM2 small-molecule inhibitors. We report herein a reversible ring opening-cyclization reaction for some of these spirooxindoles, which affords four diastereomers from a single compound. Our biochemical binding data showed that the stereo-chemistry in this class of compounds has a major effect on their binding affinities to MDM2; with >100-fold difference between the most potent and the least potent stereoisomers. Our study has led to the identification of a set of highly potent MDM2 inhibitors with a stereochemistry that is different from that of our previously reported compounds. The most potent compound (MI-888) binds to MDM2 with a Ki value of 0.44 nM and achieves complete and long-lasting tumor regression in an animal model of human cancer.
Part of quercetin flows into the colon after escaping the absorption of the small intestine and will be degraded by colonic microbiota. The catabolites in the colon partially determine the physiological activity of quercetin.
Seven gut bacteria isolated from human feces were utilized to in vitro ferment quercetin. Their catabolites were analyzed with high-performance liquid chromatography and mass spectrometry, and the antioxidant activities of their fermented broths were compared with that of quercetin.
One metabolite, 3,4-dihydroxyphenylacetic acid, was produced by both C. perfringens and B. fragilis transforming quercetin. No other metabolites were detected in the other fermented broths. The antioxidant activities of all strains fermenting quercetin reached the highest values at the concentration of 1 mg/mL quercetin in broth; the fermented products of C. perfringens and B. fragilis presented stronger activities than those of other strains at most concentrations of quercetin in broth. Additionally, all of the fermented broths presented a decline of the antioxidant activities compared to quercetin. Therefore, the antioxidant activity of quercetin will be lost when it reaches the human colon because of the gut bacterial fermentation.
This is the first study to report that quercetin can be degraded by C. perfringens and B. fragilis and transformed to the same metabolite, 3,4-dihydroxyphenylacetic acid, and that antioxidant activities decline when quercetin is fermented by seven gut bacteria.
quercetin; gut bacteria; catabolites; antioxidant activity
Our previously reported Bcl-2/Bcl-xL inhibitor, 4, effectively inhibited tumor growth but failed to achieve complete regression in vivo. We have now performed extensive modifications on its pyrrole core structure, which has culminated in the discovery of 32 (BM-1074). Compound 32 binds to Bcl-2 and Bcl-xL proteins with Ki values of < 1 nM and inhibits cancer cell growth with IC50 values of 1-2 nM in four small-cell lung cancer cell lines sensitive to potent and specific Bcl-2/Bcl-xL inhibitors. Compound 32 is capable of achieving rapid, complete and durable tumor regression in vivo at a well-tolerated dose-schedule. Compound 32 is the most potent and efficacious Bcl-2/Bcl-xL inhibitor reported to date.
Curcumin, a natural product derived from the plant Curcuma longa, has been found to have anti-inflammatory, antineoplastic and antifibrosis effects. It has been reported that curcumin attenuates allergic airway inflammation in mice through inhibiting NF-κB and its downstream transcription factor GATA3. It also has been proved the antineoplastic effect of curcumin through down-regulating Notch1 receptor and its downstream nuclear transcription factor NF-κB levels. In this study, we aimed to investigate the anti-inflammatory effect of curcumin on acute allergic asthma and its underlying mechanisms. 36 male BALB/c mice were randomly divided into four groups (normal, asthma, asthma+budesonide and asthma+curcumin groups). BALF (bronchoalveolar lavage fluid) and lung tissues were analyzed for airway inflammation and the expression of Notch1, Notch2, Notch3, Notch4 and the downstream transcription factor GATA3. Our findings showed that the levels of Notch1 and Notch2 receptors were up-regulated in asthma group, accompanied by the increased expression of GATA3. But the expression of Notch2 receptor was lower than Notch1 receptor. Curcumin pretreatment improved the airway inflammatory cells infiltration and reversed the increasing levels of Notch1/2 receptors and GATA3. Notch3 receptor was not expressed in all of the four groups. Notch4 receptor protein and mRNA expression level in the four groups had no significant differences. The results of the present study suggested that Notch1 and Notch2 receptor, major Notch1 receptor, played an important role in the development of allergic airway inflammation and the inhibition of Notch1–GATA3 signaling pathway by curcumin can prevent the development and deterioration of the allergic airway inflammation. This may be a possible therapeutic option of allergic asthma.
curcumin; asthma; airway inflammation; Notch; GATA3
Mesorhizobium huakuii 7653R occurs either in nitrogen-fixing symbiosis with its host plant, Astragalus sinicus, or free-living in the soil. The M. huakuii 7653R genome has recently been sequenced. To better understand the complex biochemical and developmental changes that occur in 7653R during bacteroid development, RNA-Seq and Microarrays were used to investigate the differential transcriptomes of 7653R bacteroids and free-living cells. The two approaches identified several thousand differentially expressed genes. The most prominent up-regulation occurred in the symbiosis plasmids, meanwhile gene expression is concentrated to a set of genes (clusters) in bacteroids to fulfill corresponding functional requirements. The results suggested that the main energy metabolism is active while fatty acid metabolism is inactive in bacteroid and that most of genes relevant to cell cycle are down-regulated accordingly. For a global analysis, we reconstructed a protein-protein interaction (PPI) network for 7653R and integrated gene expression data into the network using Cytoscape. A highly inter-connected subnetwork, with function enrichment for nitrogen fixation, was found, and a set of hubs and previously uncharacterized genes participating in nitrogen fixation were identified. The results described here provide a broader biological landscape and novel insights that elucidate rhizobial bacteroid differentiation, nitrogen fixation and related novel gene functions.
Pre-eclampsia (PE) is thought to be a pregnancy-induced autoimmune disease. Despite several strategies carried out for targeting specific factors relevant to its pathogenesis, PE remains potentially fatal to some patients. Here, we reported a way to isolate mesenchymal stem cells (MSCs) from decidua. The MSCs not only exhibited differentiation and self-renewal capacities, they also possessed immunomodulatory functions and secreted some soluble mediators including IL-6, TGF-β, IDO, VEGF and COX-2. Most importantly, the MSCs were specifically provided with the ability to suppress T cells proliferation by IDO in response to inflammatory cytokine IFN-γ. Moreover, we developed a Th1 cell-induced PE mouse model which displayed a high level of pathogenesis factor TNF-α. Strikingly, MSCs-based therapy significantly ameliorated both clinical and histopathological severity of PE symptoms including decreasing the blood pressure and proteinuria, suppressing glomerulonephritis, protecting the feto-placental development. The therapy also reversed abnormal TNF-α expression in uterine and splenic lymphocytes. These data suggest that MSCs may ameliorate Th1-induced PE-like symptoms in mice via the suppression of TNF-α and MSCs-based therapy may provide a potential novel method for PE.
Geographic barriers and Quaternary climate changes are two major forces driving the evolution, speciation, and genetic structuring of extant organisms. In this study, we used Pinus armandii and eleven other Asian white pines (subsection Strobus, subgenus Pinus) to explore the influences of geographic factors and Pleistocene climatic oscillations on species in South China, a region known to be centers of plant endemism and biodiversity hotspots. Range-wide patterns of genetic variation were investigated using chloroplast and mitochondrial DNA markers, with extensive sampling throughout the entire range of P. armandii. Both cpDNA and mtDNA revealed that P. armandii exhibits high levels of genetic diversity and significant population differentiation. Three geographically distinct subdivisions corresponding to the Qinling-Daba Mountains (QDM), Himalaya-Hengduan Mountains (HHM) and Yungui Plateau (YGP) were revealed in mainland China by cpDNA. Their break zone was located in the southeastern margin of the Qinghai-Tibetan Plateau (QTP). A series of massive mountains, induced by the QTP uplift, imposed significant geographic barriers to genetic exchange. The disjunct distribution patterns of ancestral haplotypes suggest that a large continuous population of the white pines may have existed from southwest to subtropical China. Repeated range shifts in response to the Pleistocene glaciations led to the isolation and diversification of the subtropical species. The two Taiwanese white pines share a common ancestor with the species in mainland China and obtain their chloroplasts via long-distance pollen dispersal from North Asian pines. Distinct genetic patterns were detected in populations from the Qinling-Daba Mountains, Yungui Plateau, Himalaya-Hengduan Mountains, and subtropical China, indicating significant contributions of geographic factors to the genetic differentiation in white pines. Our study depicts a clear picture of the evolutionary history of Chinese white pines and highlights the heterogeneous contributions of geography and Pleistocene climatic fluctuations to the extremely high plant species diversity and endemism in South China.
Apoptosis resistance is a hallmark of human cancer. Research in the last two decades has identified key regulators of apoptosis, including inhibitor of apoptosis proteins (IAPs). These critical apoptosis regulators have been targeted for the development of new cancer therapeutics. In this article, we will discuss three members of IAP proteins, namely XIAP, cIAP1 and cIAP2, as cancer therapeutic targets and the progress made in developing new cancer therapeutic agents to target these IAP proteins.
Bcl-2 and Bcl-xL anti-apoptotic proteins are attractive cancer therapeutic targets. We have previously reported the design of 4,5-diphenyl-1H-pyrrole-3-carboxylic acids as a class of potent Bcl-2/Bcl-xL inhibitors. In the present study, we report our structure-based optimization for this class of compounds based upon the crystal structure of Bcl-xL complexed with a potent lead compound. Our efforts accumulated into the design of compound 30 (BM-957), which binds to Bcl-2 and Bcl-xL with Ki <1 nM and has low nanomolar IC50 values in cell growth inhibition in cancer cell lines. Significantly, compound 30 achieves rapid, complete and durable tumor regression in the H146 small-cell lung cancer xenograft model at a well-tolerated dose-schedule.
In the intrinsic pathway of apoptosis, cell-damaging signals promote the release of cytochrome c from mitochondria, triggering activation of the Apaf-1 and caspase-9 apoptosome. The ubiquitin E3 ligase MDM2 decreases the stability of the proapoptotic factor p53. We show that it also coordinated apoptotic events in a p53-independent manner by ubiquitylating the apoptosome activator CAS and the ubiquitin E3 ligase HUWE1. HUWE1 ubiquitylates the antiapoptotic factor Mcl-1, and we found that HUWE1 also ubiquitylated PP5 (protein phosphatase 5), which indirectly inhibited apoptosome activation. Breast cancers that are positive for the tyrosine receptor kinase HER2 (human epidermal growth factor receptor 2) tend to be highly aggressive. In HER2-positive breast cancer cells treated with the HER2 tyrosine kinase inhibitor lapatinib, MDM2 was degraded and HUWE1 was stabilized. In contrast, in breast cancer cells that acquired resistance to lapatinib, the abundance of MDM2 was not decreased and HUWE1 was degraded, which inhibited apoptosis, regardless of p53 status. MDM2 inhibition overcame lapatinib resistance in cells with either wild-type or mutant p53 and in xenograft models. These findings demonstrate broader, p53-independent roles for MDM2 and HUWE1 in apoptosis and specifically suggest the potential for therapy directed against MDM2 to overcome lapatinib resistance.
Bcl-2 and Bcl-xL are key apoptosis regulators and attractive cancer therapeutic targets. We have designed and optimized a class of small-molecule inhibitors of Bcl-2 and Bcl-xL containing a 4,5-diphenyl-1H-pyrrole-3-carboxylic acid core structure. A 1.4 Å resolution crystal structure of a lead compound, 12, complexed with Bcl-xL has provided a basis for our optimization. The most potent compounds, 14 and 15, bind to Bcl-2 and Bcl-xL with subnanomolar Ki values and are potent antagonists of Bcl-2 and Bcl-xL in functional assays. Compounds 14 and 15 inhibit cell growth with low nanomolar IC50 values in multiple small-cell lung cancer cell lines and induce robust apoptosis in cancer cells at concentrations as low as 10 nM. Compound 14 also achieves strong antitumor activity in an animal model of human cancer.
Employing a structure-based strategy, we have designed a new class of potent small-molecule inhibitors of the anti-apoptotic proteins Bcl-2 and Bcl-xL. An initial lead compound with a new scaffold was designed based upon the crystal structure of Bcl-xL and FDA-approved drugs and was found to have an affinity of 100 μM to both Bcl-2 and Bcl-xL. Linking this weak lead to another weak-affinity fragment derived from Abbott's ABT-737 led to an improvement of the binding affinity by a factor of >10,000. Further optimization ultimately yielded compounds with subnanomolar binding affinities to both Bcl-2 and Bcl-xL and potent cellular activity. The best compound (21) binds to Bcl-xL and Bcl-2 with Ki < 1 nM, inhibits cell growth in the H146 and H1417 small-cell lung cancer cell lines with IC50 values of 60–90 nM and induces robust cell death in the H146 cancer cell line at 30–100 nM.