[Expression of lncRNA MIR210HG in preeclampsia placental tissue and its functional analysis].

Objective: To investigate the differential expression of long non-coding RNA (lncRNA) in placental tissues of women with preeclampsia (PE) and the effect of MIR210HG on the biological function of HTR8/SVneo cells. Methods: A total of 39 cases of PE women (PE group) and 39 cases of normal pregnant women (CTL group) admitted to the Affiliated Hospital of Qingdao University from July 2018 to July 2019 were collected. (1) Transcriptome sequencing (RNA-seq) was used to analyze the differentially expressed lncRNAs in the placental tissues of the two groups. (2) The expression level of MIR210HG, one of the differentially expressed lncRNAs, in the placental tissues of the two groups was detected by real-time quantitative PCR. And the correlations between the expression level of MIR210HG and systolic blood pressure, diastolic blood pressure and neonatal birth weight were analyzed. (3) The constructed small interfering RNA and negative control (NC) RNA were transfected into the HTR8/SVneo cells. The cells were divided into MIR210HG knockdown (KD) group and NC group. The effects of living cell counting (CCK-8) and transwell assay on the proliferation and migration of HTR8/SVneo cells were detected. (4) RNA interacting with MIR210HG was predicted using the Encyclopedia of RNA Interactomes (ENCORI) database. Gene Ontology (GO) functional annotation, Kyoto Encyclopedia of Gene and Genomes (KEGG) and BioCarta pathway enrichment analysis were performed. Results: (1) A total of 26 significantly differentially expressed lncRNAs were found by RNA-seq, among which 21 lncRNAs were up-regulated and 5 lncRNAs were down-regulated. (2) The relative expression level of MIR210HG in the PE group was significantly higher than that in the CTL group (9.30±1.90 and 1.10±0.20, respectively; t=4.425, P<0.01). The relative expression level of MIR210HG had positive linear correlation with systolic blood pressure (r2=0.234, P<0.05) and diastolic blood pressure (r2=0.190, P<0.05), but had a negative linear correlation with newborn birth weight (r2=0.157, P<0.05). (3) Compared with the NC group, the proliferation and migration ability of HTR8/SVneo cells in the KD group were increased (all P<0.05). (4) A total of 38 RNAs that might interact with MIR210HG were predicted by ENCORI database. GO functional annotation analysis showed that MIR210HG might be involved in the functions of 27 pathways, including the regulation of production of molecular mediator of immune response, etc; KEGG pathway analysis showed that MIR210HG might be involved in the function of 8 pathways including allograft rejection, etc; Biocarta pathway analysis showed that MIR210HG may be involved in the functions of 8 pathways, including the eukaryotic initiation factor (eIF) pathway, etc. Conclusion: The expression of MIR210HG is up-regulated in the placental tissue of PE women, and MIR210HG might be a regulator of the biological behavior of trophoblast cells.

Glutathione S-transferase P1 rs1695 A>G polymorphism and breast cancer risk: evidence from a meta-analysis.

Breast cancer (BC) is the most widespread cause of cancer-related deaths in women. Many published studies have assessed the association between the glutathione S-transferase P1 (GSTP1) rs1695 polymorphism and BC risk. However, the effect of the GSTP1 rs1695 polymorphism on BC risk has remained controversial. Therefore, this meta-analysis was conducted to obtain a comprehensive estimation of this association. A total of 20,615 cases and 20,481 controls from thirty-six case-control trials were extracted from an online literature survey. The meta-analysis indicated that the GSTP1 rs1695 A>G polymorphism did not contribute to the susceptibility of BC when the overall population was considered. However, intriguingly, this polymorphism was significantly associated with increased risk of BC in Asian women [GG vs AA: odds ratio (OR) = 1.4, 95% confidence interval (CI): 1.06-1.88, P = 0.02; AG vs AA: OR = 1.08, 95%CI = 1.00-1.16, P = 0.05; GG/AG vs AA: OR = 1.11, 95%CI = 1.04-1.19, P = 0.00]. Moreover, a subgroup analysis based on the source of control groups showed a marked increase in BC susceptibility in hospital-based control subjects (GG vs AA: OR = 1.28, 95%CI = 1.10-1.48, P= 0.00; GG vs AG/AA: OR = 1.22, 95%CI = 1.06-1.41, P = 0.00; GG/AG vs AA: OR = 1.10, 95%CI = 1.02-1.18, P = 0.00). In conclusion, our study indicated that the GSTP1 rs1695 A>G polymorphism was correlated with elevated BC risk in Asian women. Our results must be validated with further research.

Environmental factor analysis of cholera in China using remote sensing and geographical information systems.

Cholera is one of a number of infectious diseases that appears to be influenced by climate, geography and other natural environments. This study analysed the environmental factors of the spatial distribution of cholera in China. It shows that temperature, precipitation, elevation, and distance to the coastline have significant impact on the distribution of cholera. It also reveals the oceanic environmental factors associated with cholera in Zhejiang, which is a coastal province of China, using both remote sensing (RS) and geographical information systems (GIS). The analysis has validated the correlation between indirect satellite measurements of sea surface temperature (SST), sea surface height (SSH) and ocean chlorophyll concentration (OCC) and the local number of cholera cases based on 8-year monthly data from 2001 to 2008. The results show the number of cholera cases has been strongly affected by the variables of SST, SSH and OCC. Utilizing this information, a cholera prediction model has been established based on the oceanic and climatic environmental factors. The model indicates that RS and GIS have great potential for designing an early warning system for cholera.

The association of serum anti-ribosomal P antibody with clinical and serological disorders in systemic lupus erythematosus: a systematic review and meta-analysis.

OBJECTIVE: Anti-ribosomal P (anti-P) antibody is a serological specific marker of systemic lupus erythematosus (SLE). The aim of this study is to investigate the association of this antibody with clinical and serological disorders in SLE. METHODS: All relevant literature was retrieved from PubMed, EMBASE, Web of Science and CNKI databases. The qualities of these studies were evaluated using a modified version of the Newcastle-Ottawa scale. The associations of anti-P antibody with clinical and serological disorders were determined by the pooled odds ratio (OR) and the confidence interval (CI) calculated using meta-analysis with the Mantel-Haenszel method. RESULTS: Sixteen cohort studies with 2355 patients were included in this study. Malar rash, oral ulcer and photosensitivity were strongly associated with serum anti-P antibody, with OR (95% CI) values of 2.05 (1.42-2.92), 1.49 (1.05-2.13) and 1.44 (1.08-1.91), respectively. Arthritis and renal involvement were not associated with anti-P antibody, whereas a high heterogeneity was observed due to ethnicity and publication bias, respectively. Neuropsychiatric SLE (NPSLE), hepatic involvement, anti-dsDNA, anti-Sm and anti-cardiolipin antibodies (aCL) were observed more frequently in anti-P positive patients than in negative patients. Studies on hepatic involvement showed a low precision with substantially broad CI (2.56-11.2). A high heterogeneity presented among studies on NPSLE, anti-Sm and aCL. CONCLUSIONS: Anti-P antibody is significantly associated with malar rash, oral ulcer, photosensitivity and serum anti-dsDNA antibody, and potentially associated with NPSLE, hepatic damage, serum anti-Sm and aCL.

Decreased risk of developing lung cancer in subjects carrying the CLPTM1L rs401681 (G>A) polymorphism: evidence from a meta-analysis.

A genome-wide association study revealed that a single nucleotide polymorphism, CLPTM1L - rs401681 (G>A), located at the 5p15.33 locus was significantly associated with increased risk of various cancers; however, its association with lung cancer is currently inconclusive. In order to explore the relationship between this polymorphism and lung cancer risk more precisely, we performed a meta-analysis of eight eligible studies involving 9935 cases and 11,261 controls. The pooled odds ratio (OR) and the 95% confidence interval (CI) were calculated using a fixed- or random-effect models. Results indicated that this polymorphism was significantly associated with lung cancer risk in all genetic models (GA vs GG: OR = 0.88, 95%CI = 0.83-0.94; AA vs GG: OR = 0.81, 95%CI = 0.70-0.93; AA/GA vs GG: OR = 0.86, 95%CI = 0.81-0.91; AA vs GA/GG: OR = 0.86, 95%CI = 0.76-0.99). An analysis stratified by ethnicity and source of controls revealed a significantly decreased risk among European groups and population-based studies in all genetic models, and among Asian populations only in the dominant model comparison. Additionally, in a subgroup analysis by histology type, the CLPTM1L rs401681 polymorphism was found to significantly decrease the risks of both adenocarcinoma and squamous cell carcinoma of the lung in all genetic models. In conclusion, our study indicated that the CLPTM1L - rs401681 (G>A) polymorphism was significantly associated with decreased lung cancer risk, especially among European populations. Due to some minor limitations, our findings should be confirmed in further studies.

Epidemiological features of hand-foot-and-mouth disease in Shenzhen, China from 2008 to 2010.

This study analysed the spatio-temporal distribution and propagation of hand-foot-and-mouth disease (HFMD) in Shenzhen from 2008 to 2010. Specifically, we examined the epidemiological data, temporal distribution and spatial distribution, and then the relationship between meteorological, social factors and the number of reported HFMD cases was analysed using Spearman's rank correlation. Finally, a geographically weighted regression model was constructed for the number of reported HFMD cases in 2009. It was found that three independent variables, i.e. the number of reported HFMD cases in 2008 and, annual average temperature and precipitation, had different spatial impacts on the number of reported HFMD cases in 2009. In addition, these variables accounted for the propagation mechanism of HFMD in the centre and east of Shenzhen, where the high incidence rate areas are located. These results will be of great help in understanding the spatio-temporal distribution of HFMD and developing approaches to prevent this disease.

Expression of aldosterone synthase and adrenocorticotropic hormone receptor in adrenal incidentalomas from normotensive and hypertensive patients: Distinguishing subclinical or atypical primary aldosteronism from adrenal incidentaloma.

The present study aimed to investigate the expression of aldosterone synthase (CYP11B2), adrenocorticotropic hormone receptor (ACTH-R) and their regulating transcription factors in adrenal incidentalomas (AIs) from normotensive and hypertensive patients to distinguish subclinical or atypical primary aldosteronism (PA) from AIs. Total RNA was extracted from 8 normal adrenal cortices (NAs), 46 AIs, 15 aldosterone-producing adenomas (APAs) and 6 idiopathic hyperaldosteronisms (IHAs). Real-time quantitative polymerase chain reaction (PCR) and immunohistochemistry were performed to determine the mRNA and protein expression of CYP11B2, ACTH-R, steroidogenic factor-1 (SF1) and dosage-sensitive sex reversal, adrenal hypoplasia congenita, critical region on the X chromosome, gene-1 (DAX-1) in the different tissues. The AI hypertensive subgroup displayed increased plasma aldosterone concentration (PAC) and PAC/PRA ratio (ARR) and decreased plasma renin activity (PRA) compared to the normotensive group. CYP11B2, ACTH-R and SF1 mRNAs were significantly higher in the APA group compared to the other groups, and gradually increased in AI hypertensive samples. DAX-1 mRNA was expressed faintly in PA compared with NA. In normotensive-AI samples, DAX-1 mRNA was higher compared to PA and AI hypertensive samples. Significant differences in gene expression levels in AIs were observed between probable and improbable PA patients. Immunohistochemical results were consistent with those of real-time PCR. Plasma aldosterone levels were positively correlated with CYP11B2, ACTH-R and SF1 mRNA and inversely correlated with DAX-1 mRNA. In conclusion, a significant number of hypertensive-AI patients may have subclinical forms of PA. CYP11B2, ACTH-R and their regulating transcription factors may be noteworthy in distinguishing subclinical PA from AIs.

Clinical evaluation of extraperitoneal colostomy without damaging the muscle layer of the abdominal wall.

OBJECTIVE: This study investigated whether extraperitoneal colostomy without damaging the muscle layer of the abdominal wall is an improved surgical procedure compared with conventional sigmoid colostomy in patients undergoing abdominoperineal resection. METHODS: Patients with rectal cancer undergoing abdominoperineal resection were selected and randomly divided into two groups: the study group received extraperitoneal colostomy without damaging the muscle layer of the abdominal wall and the control group received conventional colostomy. Clinical data from both groups were analysed. RESULTS: A total of 128 patients were included: 66 received extraperitoneal colostomy without damaging the muscle layer of the abdominal wall and 62 received conventional colostomy. Significant differences between the two groups were found in relation to colostomy operating time, defaecation sensation, bowel control and overall stoma-related complications. Duration of postoperative hospital stay was also significantly different between the study groups. CONCLUSIONS: Extraperitoneal colostomy without damaging the muscle layer of the abdominal wall was found to be an improved procedure compared with conventional sigmoid colostomy in abdominoperineal resection, and may reduce colostomy-related complications, shorten operating time and postoperative hospital stay, and potentially improve patients' quality of life.

Immunization of mice with plasmids coexpressing HPV16 E5 and the novel oncogene hWAPL.

The novel human oncogene hWAPL is associated with uterine cervical cancer. The HPV16 E5 oncoprotein could induce genomic instability in normal human cells. However, the mechanism of E5 interaction with hWAPL still awaits definition. In our present studies, the eukaryotic expression plasmids, pcDNA3-hWAPL and pcDNA3-hWAPL-E5 were constructed and carried out to vaccinate mice directly. The result that indicated the polyclonal antibody titer in immunized mice sera was increased by enzyme-linked immunosorbent assay. In addition, the proliferative responses of immunized mice spleen cells showed the optical densities values in vaccinated group remarkably higher than that in the control group. In conclusion, the recombinant plasmids could induce strong humoral and cellular immune response and exhibited great potential as therapeutic targets in the treatment of cervical cancer. However, the result didn't show significant difference in group with coexpression of HPV16 E5-hWAPL and group with only hWAPL expression. Consistent with these observations, we demonstrated that HPV16 E5 was not the optimal factor to cooperate with hWAPL in gene therapy.

Experimental investigation on moving chemical reaction boundary theory for weak-acid-strong-base system with background electrolyte KCl in large concentration.

In this report, the moving chemical reaction boundary (MCRB) was formed with the weak acid of acetic acid (HAc) and the strong alkali of NaOH, coupled with the excess of background electrolyte KCl. The experiments were compared with the predictions by the moving chemical reaction boundary equation (MCRBE). It is very interesting that (1) the experimental results are in good agreement with the predictions with the original MCRBE if the MCRB is an anodic moving boundary, (2) however, the experiments are extremely far away from the predictions with the original MCRBE if a cathodic moving boundary. Hence, the original MCRBE must be corrected under the later situation of cathodic moving MCRB. The corrected MCRBE was well quantitatively proved to be valid for the cathodic moving MNRB formed with the same electrolytes of HAc, NaOH and KCl.

Activation of the Fas pathway independently of Fas ligand during apoptosis induced by camptothecin in p53 mutant human colon carcinoma cells.

The present study explored the role of the cell surface receptor Fas (CD95/APO-1) in apoptosis induced by camptothecin (CPT) in the HT29 colon carcinoma cell line. CPT-induced apoptosis was associated with high molecular weight DNA fragmentation as measured by filter elution. This fragmentation was inhibited by the caspase inhibitor, z-VAD-fmk and by cycloheximide, which also prevented proteolytic activation of caspase-3 and poly(ADP-ribose)polymerase cleavage. Under such conditions, Fas, Fas ligand, Bax, and p21 expression were increased and Fas recruited the FADD adaptor. Fas expression increase was blocked by cycloheximide but not by z-VAD-fmk, consistent with caspase activation downstream from Fas. Treatment of HT29 cells with FasL or with the CH-11 agonistic anti-Fas antibody potentiated the apoptotic response of cells treated with CPT. The anti-Fas blocking antibody ZB4 and the Fas-ligand inhibitor failed to protect HT29 cells from CPT-induced apoptosis. Such a protection was obtained by transient expression of constructs encoding a dominant-negative mutant of FADD, FADD in an antisense orientation and E8 or MC159 viral proteins that inhibit Fas-induced apoptosis at the level of FADD and procaspase-8, respectively. Together, these data show that topoisomerase I-mediated DNA damage-induced apoptosis involves activation of the Fas pathway without detectable Fas-ligand requirement in CPT-treated cells.

Corrections to moving chemical reaction boundary equation for weak reactive electrolytes under the existence of background electrolyte KCl in large concentrations.

In this report, the moving chemical reaction boundary (MCRB) was formed by the weak reaction electrolytes of NH3.H2O and CH3COOH under the existence of background electrolyte KCl in large concentrations, the experiments were compared with the predictions by the moving chemical reaction boundary equation (MCRBE) for weak reactive electrolytes. It was found that the experimental results are far from the predictions with the MCRBE. So the MCRBEs must be corrected under the given experimental conditions. The corrected MCRBEs are given for the MCRB formed with weak reactive electrolytes coupled with KCl at high concentrations.

Experimental study on moving neutralization reaction boundary created with the strong reactive electrolytes of HCl and NaOH in agarose gel.

In this paper, a moving neutralization reaction boundary (MNRB) is created with the strong reactive electrolytes of HCl and NaOH in agarose gel. The motions of the MNRB are investigated and compared with the predictions with the theory of the moving chemical reaction boundary (MCRB). The results show that, under appreciate experimental conditions, the experiments on the MNRB are exactly in coincidence with the predictions with the MCRB theory. Thus, the results excellently demonstrate that the MCRB theory is valid for the MNRB formed with the strong reactive electrolytes of HCl and NaOH. Additionally, it is, as discussed in this paper, imperative to develop a method to obtain ionic mobility at different temperatures and ionic strengths, in order to investigate the movements of the MCRB more efficiently.

The unvalidity of Kohlrausch' regulating function for Svensson's isoelectric focusing and stationary electrolysis at steady state.

Kohlrausch' regulating function is of important significance in the field of electrophoresis. In this paper, the relative regulating function is defined from Kohlrausch' regulating function. The relative values, including the limited values, of the regulating function for the stationary electrolysis of salt, on which the classic isoelectric focusing (IEF) is based, are computed and compared with the computer program of the QBASIC written by us. The results directly demonstrate that, (1) in a few cases the regulating function is valid for the stationary electrolysis and IEF, whereas (2) the function is, in most of cases, not valid for the stationary electrolysis and IEF at steady-state. Those findings may be useful for the studies on the relationships between Kohlrausch' regulating function and IEF and for the classification of numerous electrophoretic techniques.

Replication-mediated DNA damage by camptothecin induces phosphorylation of RPA by DNA-dependent protein kinase and dissociates RPA:DNA-PK complexes.

UNLABELLED: Replication protein A (RPA) is a DNA single-strand binding protein essential for DNA replication, recombination and repair. In human cells treated with the topoisomerase inhibitors camptothecin or etoposide (VP-16), we find that RPA2, the middle-sized subunit of RPA, becomes rapidly phosphorylated. This response appears to be due to DNA-dependent protein kinase (DNA-PK) and to be independent of p53 or the ataxia telangiectasia mutated (ATM) protein. RPA2 phosphorylation in response to camptothecin required ongoing DNA replication. Camptothecin itself partially inhibited DNA synthesis, and this inhibition followed the same kinetics as DNA-PK activation and RPA2 phosphorylation. DNA-PK activation and RPA2 phosphorylation were prevented by the cell-cycle checkpoint abrogator 7-hydroxystaurosporine (UCN-01), which markedly potentiates camptothecin cytotoxicity. The DNA-PK catalytic subunit (DNA-PKcs) was found to bind RPA which was replaced by the Ku autoantigen upon camptothecin treatment. DNA-PKcs interacted directly with RPA1 in vitro. We propose that the encounter of a replication fork with a topoisomerase-DNA cleavage complex could lead to a juxtaposition of replication fork-associated RPA and DNA double-strand end-associated DNA-PK, leading to RPA2 phosphorylation which may signal the presence of DNA damage to an S-phase checkpoint mechanism. KEYWORDS: camptothecin/DNA damage/DNA-dependent protein kinase/RPA2 phosphorylation

Lamin B phosphorylation by protein kinase calpha and proteolysis during apoptosis in human leukemia HL60 cells.

Protein phosphorylation plays an important role in signal transduction, but its involvement in apoptosis still remains unclear. In this report, the p53-null human leukemia HL60 cells were used to investigate phosphorylation and degradation of lamin B during apoptosis. We found that lamin B was phosphorylated within 1 h after addition of the DNA topoisomerase I inhibitor, camptothecin, and that lamin B phosphorylation preceded lamin B degradation and DNA fragmentation. Using a cell-free system we also found that cytosol from camptothecin-treated cells induced lamin B phosphorylation and degradation in isolated nuclei from untreated HL60 cells. Lamin B phosphorylation was prevented by the protein kinase C (PKC) inhibitor 7-hydroxystaurosporine (UCN-01) but not by the Cdc2 inhibitor, flavopiridol. Phosphorylation of lamin B was inhibited by immunodepletion of PKCalpha from activated cytosol and was restored by addition of purified PKCalpha. PKCalpha activity also increased rapidly as lamin B was phosphorylated after initiation of the apoptotic response in HL60 cells. These data suggest that lamin B is phosphorylated by PKCalpha and proteolyzed before DNA fragmentation in HL60 cells undergoing apoptosis.

Abrogation of an S-phase checkpoint and potentiation of camptothecin cytotoxicity by 7-hydroxystaurosporine (UCN-01) in human cancer cell lines, possibly influenced by p53 function.

7-Hydroxystaurosporine (UCN-01) is a selective protein kinase C inhibitor in clinical trial for cancer treatment. In this study, we found that nanomolar concentrations of camptothecin (CPT), a topoisomerase I inhibitor, arrest or delay cell cycle progression during the S and G2 phases in p53 mutant human colon carcinoma HT29 cells and that UCN-01 abrogates the S-phase arrest or delay induced by CPT. Under these conditions, CPT increased cyclin A levels and cyclin A/cyclin-dependent kinase 2 activity. UCN-01 prevented the increase of cyclin A/cyclin-dependent kinase 2 activity induced by CPT and enhanced Cdc2 kinase activity. Replication protein A (RPA2) was hyperphosphorylated after CPT treatment, and this effect was also abrogated by UCN-01. UCN-01 potentiated the cytotoxicity of CPT and reduced by 6-fold the concentration of CPT required to kill 50% of the HT-29 cells, as determined by clonogenic assays. This effect was observed at concentrations of UCN-01 that alone were not cytotoxic and had no detectable effect on cell cycle progression. UCN-01 markedly potentiated the cytotoxicity of CPT also in HCT116/E6 and MCF-7/ADR cells defective for p53 function, whereas significantly less potentiation was observed in p53-wild-type HCT116 and MCF-7 cells. These results suggest the existence of an S-phase checkpoint that delays replication and that may extend the time available for DNA repair. Thus, pharmacological abrogation of CPT-induced S- and G2-phase checkpoints by UCN-01 may provide an effective strategy for enhancing the chemotherapeutic activity of CPT, particularly against p53-defective tumors.

Activation of PKCalpha downstream from caspases during apoptosis induced by 7-hydroxystaurosporine or the topoisomerase inhibitors, camptothecin and etoposide, in human myeloid leukemia HL60 cells.

We previously demonstrated that the anticancer agent and protein kinase C (PKC) inhibitor 7-hydroxystaurosporine (UCN-01) induces apoptosis independently of p53 and protein synthesis in HL60 cells. We now report the associated changes of PKC isoforms. PKCalpha, betaI, betaII, delta, and zeta activities were measured after immunoprecipitation of cytosols from UCN-01-treated HL60 cells. UCN-01 had no effect on PKCzeta and inhibited kinase activity of PKCbetaI, betaII, and delta. PKCalpha activity was initially inhibited at 1 h, and subsequently increased as cells underwent apoptosis 3 h after the beginning of UCN-01 treatment. Camptothecin (CPT) and etoposide (VP-16) also markedly enhanced PKCalpha activity during apoptosis in HL60 cells. However, CPT did not affect PKCbetaI, betaII and zeta, and activated PKCdelta. PKCalpha activation was not due to increased protein levels or proteolytic cleavage but was associated with PKCalpha autophosphorylation in vitro and increased phosphorylation in vivo. We also found that not only PKC delta but also PKC betaI was proteolytically activated in HL60 cells during apoptosis. The PKCalpha activation and hyperphosphorylation were abrogated by N-benzyloxycarbonyl-Val-Ala-Asp(O-methyl)-fluoromethylketone (z-VAD-fmk) under conditions that abrogated apoptosis. z-VAD-fmk also prevented PKCdelta and betaI proteolytic activation. Together these findings suggest that caspases regulate PKC activity during apoptosis in HL60 cells. At least two modes of activation were observed: hyperphosphorylation for PKCalpha and proteolytic activation for PKC delta and betaI.

Yuanhuacin A is a selective antagonist of phorbol ester receptor in protein kinase C.

Protein kinase C with a molecular weight of 82 kD has been purified to electrophoresis homogeneous from rat brain through a series of chromatography columns including DE-52, Sepharose G-200 and phenyl-Sepharose. The enzyme possessed autophosphorylation activity. Yuanhuacin A inhibited the 3H-phorbol-12, 13-dibutyrate (3H-PdBu) binding of PKC with an IC50 value of 1.48 +/- 0.28 x 10(-8) mol/L when the concentration of 3H-PdBu was 1.5 x 10(-9) mol/L (Ki = 1.2 x 10(-8) mol/L). Yuanhuacin A inhibited the PdBu-stimulated PKC activity in the catalysis of the phosphorylation of Histone III-S with an IC50 of 2.82 +/- 0.37 x 10(-9) mol/L (PdBu = 10(-6) mol/L), while it had no effect on the basal and Ca(2+)-stimulated PKC activity in the same assay system. This result suggests that Yuanhuacin A is a selective antagonist of the phorbol ester receptor in protein kinase C.