Structurally Various Sorbicillinoids From an Endophytic Fungus Acremonium citrinum SS-g13

Three new sorbicillinoids, including trimer trisorbicillinone E (1), acremosorbicillinoids A and B (2 and 3), and a new alkaloid acremokaloid A (4), and a new natural product 2S,3S-acetyl-β-methyltryptophan (5), were isolated from an endophytic fungus Acremonium citrinum SS-g13, which is found in Fructus mori plant root. In addition, eight known sorbicillinoids (6-13) were also obtained. The new compound structures were established using NMR, HRESIMS spectra, and reported spectroscopic data. The absolute configurations of compounds 1-5, were determined by spectroscopic analysis, Snatzke's method, and time-dependent density functional theory-electronic circular dichroism (TDDFT-ECD) calculations. Compound 11 exhibited significant cholesterol efflux enhancing activity. A plausible biosynthesis pathway for the sorbicillinoids is discussed.

[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.

Expression of PD1 and BTLA on the CD8+ T Cell and γδT Cell Subsets in Peripheral Blood of Non-Small Cell Lung Cancer Patients

Objective To investigate the expression and regulation of programmed cell death protein 1 (PD1), B lymphocyte and T lymphocyte attenuator (BTLA) in peripheral blood of patients with non-small cell lung cancer (NSCLC); to examine the correlation of the mRNA levels between PD and BTLA in NSCLC. Methods Flow cytometry was used to detect the expression of PD1 and BTLA on the surfaces of CD8⁺ T cells and γδ⁺ T cells in the peripheral blood samples collected from 32 in-patients with stage IV NSCLC and 30 healthy individuals. We compared the expression of PD1 and BTLA on the surfaces of γδ⁺ T cells in the NSCLC patients with bone metastasis before and after the treatment of zoledronic acid. The correlations of PD1 and BTLA, as well as their ligands were analyzed using Pearson correlation analysis with the cBioPortal data platform. Results The frequency of PD1 on the surfaces of CD8⁺ T cells was significantly higher than that of the γδT cells in both healthy controls (t=2.324, P=0.024) and NSCLC patients（t=2.498, P=0.015). The frequency of PD1 on CD8⁺ T cells, rather than on γδ⁺ T cells, was significantly upregulated in advanced NSCLC patients compared with that in healthy controls (t=4.829, P<0.001). The PD1⁺ BTLA⁺γδT cells of the healthy controls were significantly lower than that of the NSCLC patients (t=2.422, P=0.0185). No differences in percentage of PD1⁺γδ⁺ and BTLA⁺γδ⁺ T cells were observed in 7 NSCLC patients with bone metastasis before and after zoledronic acid treatment. PD1 was positively correlated with BTLA in both lung adenocarcinoma (r=0.54; P<0.05) and lung squamous cell carcinoma (r=0.78; P<0.05). Conclusions The upregulation of co-inhibitory molecules occurs on the surfaces of both CD8⁺ T cells and γδT cells in advanced NSCLC, suggesting that these molecules were involved in regulating the inactivation of CD8⁺ T cells and γδ⁺ T cells, immune escape and tumor invasion.

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.

The role of statins in erectile dysfunction: a systematic review and meta-analysis

To evaluate the effect of statins for erectile dysfunction (ED), a systematic review of the literature was conducted in the Cochrane Library, Embase and PubMed from the inception of each database to June 2013. Only randomized controlled trials (RCTs) comparing treatment for ED with statins were identified. Placebo RCTs with the International Index of Erectile Function (IIEF) as the outcome measure were eligible for meta-analysis. A total of seven RCTs including two statins with a total of 586 patients strictly met our criteria for systematic review and five of them qualified for the meta-analysis. A meta-analysis using a random effects model showed that statins were associated with a significant increase in IIEF-5 scores (mean difference (MD): 3.27; 95% confidential interval (CI):1.51 to 5.02; P < 0.01) and an overall improvement of lipid profiles including total cholesterol (MD: −1.08; 95% CI: −1.68 to −0.48; P < 0.01), low-density lipoprotein (LDL) cholesterol (MD: −1.43; 95% CI: −2.07 to −0.79; P < 0.01), high-density lipoprotein (HDL) cholesterol (MD: 0.24; 95% CI: 0.13 to 0.35; P < 0.01) and triglycerides (TGs) (MD: −0.55; 95% CI: −0.61 to −0.48; P < 0.01). In summary, our study revealed positive consequences of these lipid-lowering drugs on erectile function, especially for nonresponders to phosphodiesterase type 5 inhibitors (PDE5Is). However, it has been reported that statin therapy may reduce levels of testosterone and aggravate symptoms of ED. Therefore, larger, well-designed RCTs are needed to investigate the double-edged role of statins in the treatment of ED.

Metabolic effects of testosterone replacement therapy on hypogonadal men with type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials

This systematic review was aimed at assessing the metabolic effects of testosterone replacement therapy (TRT) on hypogonadal men with type 2 diabetes mellitus (T2DM). A literature search was performed using the Cochrane Library, EMBASE and PubMed. Only randomized controlled trials (RCTs) were included in the meta-analysis. Two reviewers retrieved articles and evaluated the study quality using an appropriate scoring method. Outcomes including glucose metabolism, lipid parameters, body fat and blood pressure were pooled using a random effects model and tested for heterogeneity. We used the Cochrane Collaboration's Review Manager 5.2 software for statistical analysis. Five RCTs including 351 participants with a mean follow-up time of 6.5-months were identified that strictly met our eligibility criteria. A meta-analysis of the extractable data showed that testosterone reduced fasting plasma glucose levels (mean difference (MD): −1.10; 95% confidence interval (CI) (−1.88, −0.31)), fasting serum insulin levels (MD: −2.73; 95% CI (−3.62, −1.84)), HbA1c % (MD: −0.87; 95% CI (−1.32, −0.42)) and triglyceride levels (MD: −0.35; 95% CI (−0.62, −0.07)). The testosterone and control groups demonstrated no significant difference for other outcomes. In conclusion, we found that TRT can improve glycemic control and decrease triglyceride levels of hypogonadal men with T2DM. Considering the limited number of participants and the confounding factors in our systematic review; additional large, well-designed RCTs are needed to address the metabolic effects of TRT and its long-term influence on hypogonadal men with T2DM.

The role of mirabegron in overactive bladder: a systematic review and meta-analysis

OBJECTIVE

To present a systematic review assessing the efficacy and safety of mirabegron for overactive bladder (OAB).

MATERIALS AND METHODS

A literature search was performed using the Cochrane Library, MEDLINE, EMBASE and Science Citation Index Expanded. The literature reviewed included meta-analyses, randomized and nonrandomized prospective studies. We utilized mean difference (MD) to measure the mean number of incontinence episodes and the mean number of micturitions, and OAB questionnaire (OAB-q) and odds ratio (OR) to measure adverse events rates. We used the Cochrane Collaboration's Review Manager 5.1 software for statistical analysis.

RESULTS

We identified six publications that strictly met our eligibility criteria. Meta-analysis of extractable data showed that mirabegron was more effective than placebo in treating OAB despite different drug dosages in the efficacy end points: mean number of incontinence episodes per 24 h (MD -0.54; 95% CI -0.63, -0.45; p = 0.001), mean number of micturitions per 24 h (MD -0.55; 95% CI -0.63, -0.47; p = 0.001), OAB-q (MD -4.49; 95% CI -6.27, -2.71; p = 0.001) and adverse events (OR 0.99; 95% CI 0.83, 1.19; p = 0.92). When compared to tolterodine, mirabegron was more effective in terms of mean number of incontinence episodes per 24 h (MD -0.25; 95% CI -0.43, -0.06; p = 0.009). However, there were no differences between mirabegron and tolterodine in mean number of micturitions per 24 h (MD -0.17; 95% CI -0.35, 0.01; p = 0.07) and OAB-q (MD -1.09; 95% CI -2.51, 0.33; p = 0.13). Mirabegron also had a lower adverse reaction rate (OR 0.9; 95% CI 0.8, 1.0; p = 0.04).

CONCLUSIONS

In this diverse population, mirabegron was an effective and safe pharmacologic therapy for OAB.

[Expression of vascular growth factors in intestinal tissues in colorectal carcinoma patients with schistosomiasis japonica]

OBJECTIVE

To investigate the differences of mRNA quantitation and protein expression of vascular growth factors including platelet-derived endothelial cell growth factor (PD-ECGF) and vascular endothelial growth factor (VEGF) in intestinal tissues in colorectal carcinoma patients with and without schistosomiasis.

METHODS

Thirty colorectal carcinoma patients with schistosomiasis and 30 colorectal carcinoma patients without schistosomiasis were included in this study. The mRNA quantitation and protein expression of PD-ECGF and VEGF in the normal tissue, peri-carcinoma tissue as well as carcinoma tissue obtained from surgical specimens were detected by qRT-PCR and Western blot.

RESULTS

The mRNA relative quantitations of PD-ECGF in normal tissue, peri-carcinoma tissue and carcinoma tissue in the colorectal carcinoma patients with schistosomiasis were 1.726, 1.766 and 2.729 times to those in the colorectal carcinoma patients without schistosomiasis, respectively. The corresponding ones of VEGF were 2.138, 1.831 and 3.376 times, respectively. The protein expression levels of PD-ECGF and VEGF in normal tissue, peri-carcinoma tissue and carcinoma tissue were higher in the colorectal carcinoma patients with schistosomiasis than in the colorectal carcinoma patients without schistosomiasis.

CONCLUSIONS

The expressions of vascular growth factors including PD-ECGF and VEGF are higher in the colorectal carcinoma patients with schistosomiasis than in the colorectal carcinoma patients without schistosomiasis. Therefore, schistosomiasis may be one of the risk factors of colorectal cancer.

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

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.

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.

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.

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.

Gemfibrozil enhances the listeriacidal effects of fluoroquinolone antibiotics in J774 macrophages

J774 macrophage-like cells express organic anion transporters that promote the efflux of fluoroquinolone antibiotics such as norfloxacin (NFX) from these cells. Gemfibrozil (GFZ) blocks organic anion transport in J774 cells, thereby facilitating the intracellular accumulation of NFX (Cao, C., H.C. Neu, and S.C. Silverstein. 1991. J. Cell Biol. 115:467a [Abstr.]). To determine whether GFZ enhances the efficacy of fluoroquinolone antibiotics against intracellular bacterial pathogens, J774 cells were infected with Listeria monocytogenes and incubated in medium containing a fluoroquinolone antibiotic in the presence or absence of GFZ. Intracellular growth of L. monocytogenes was evaluated by lysing J774 cells and assaying for colony-forming units of Listeria. GFZ intensified the bacteriostatic effect of 4 micrograms/ml NFX and rendered 8 micrograms/ml bactericidal for L. monocytogenes. GFZ had a similar potentiating effect when used in combination with 2 micrograms/ml ciprofloxacin (CFX). CFX plus GFZ was bactericidal for intracellular L. monocytogenes. Treatment of J774 cells with NFX plus GFZ markedly reduced the cytotoxic effect of the bacteria on these cells. Over 55% of cells treated with 8 micrograms/ml NFX alone were dead 16 h after infection, whereas only 5% of cells treated with 8 micrograms/ml NFX plus GFZ were dead at 16 h. Similarly, GFZ potentiated the ability of 2 micrograms/ml to protect J774 cells against the cytocidal effect of Listeria. NFX in combination with GFZ limited cell-to-cell spread of L. monocytogenes. In antibiotic-free medium, > 99% of J774 cells contained intracellular L. monocytogenes at 14 h after infection. NFX alone in the medium did not change this outcome. However, 4 micrograms/ml NFX plus GFZ decreased bacterial spread by approximately 40% at 24 h postinfection, and 8 micrograms/ml NFX plus GFZ prevented all spread beyond the initially infected cell population. These results suggest that GFZ could be used clinically to enhance the efficacy of fluoroquinolone and of other anionic antibiotics against bacteria that grow and/or reside within macrophages and/or other cells.

J774 macrophages secrete antibiotics via organic anion transporters

Mouse macrophages and J774 macrophage-like cells express probenecid-inhibitable organic anion transporters that remove anionic dyes from the cells' cytoplasmic matrix and secrete these dyes into the extracellular medium. The present studies show that these transporters also secrete antibiotics from J774 macrophages. Penicillin G permeates J774 cells poorly, but after it was introduced into the cell cytoplasm, it was secreted in a probenecid-inhibitable fashion. The quinolone norfloxacin enters macrophages readily. Probenecid retarded the secretion of intracellular norfloxacin by J774 cells and enhanced norfloxacin accumulation three- to fourfold. Thus the intracellular accumulation of norfloxacin is regulated in part by organic anion transporters that secrete norfloxacin (and penicillin G) from J774 cells. This transport process may have clinical significance, as fluoroquinolones inhibit growth of intracellular pathogens such as mycobacteria and Brucella organisms in vitro but fail to arrest infections with these organisms in vivo.