Withaferin A: A Pleiotropic Anticancer Agent from the Indian Medicinal Plant Withania somnifera (L.) Dunal

Cancer represents the second most deadly disease and one of the most important public health concerns worldwide. Surgery, chemotherapy, radiation therapy, and immune therapy are the major types of treatment strategies that have been implemented in cancer treatment. Unfortunately, these treatment options suffer from major limitations, such as drug-resistance and adverse effects, which may eventually result in disease recurrence. Many phytochemicals have been investigated for their antitumor efficacy in preclinical models and clinical studies to discover newer therapeutic agents with fewer adverse effects. Withaferin A, a natural bioactive molecule isolated from the Indian medicinal plant Withania somnifera (L.) Dunal, has been reported to impart anticancer activities against various cancer cell lines and preclinical cancer models by modulating the expression and activity of different oncogenic proteins. In this article, we have comprehensively discussed the biosynthesis of withaferin A as well as its antineoplastic activities and mode-of-action in in vitro and in vivo settings. We have also reviewed the effect of withaferin A on the expression of miRNAs, its combinational effect with other cytotoxic agents, withaferin A-based formulations, safety and toxicity profiles, and its clinical potential.

Elucidating Role of Reactive Oxygen Species (ROS) in Cisplatin Chemotherapy: A Focus on Molecular Pathways and Possible Therapeutic Strategies

The failure of chemotherapy is a major challenge nowadays, and in order to ensure effective treatment of cancer patients, it is of great importance to reveal the molecular pathways and mechanisms involved in chemoresistance. Cisplatin (CP) is a platinum-containing drug with anti-tumor activity against different cancers in both pre-clinical and clinical studies. However, drug resistance has restricted its potential in the treatment of cancer patients. CP can promote levels of free radicals, particularly reactive oxygen species (ROS) to induce cell death. Due to the double-edged sword role of ROS in cancer as a pro-survival or pro-death mechanism, ROS can result in CP resistance. In the present review, association of ROS with CP sensitivity/resistance is discussed, and in particular, how molecular pathways, both upstream and downstream targets, can affect the response of cancer cells to CP chemotherapy. Furthermore, anti-tumor compounds, such as curcumin, emodin, chloroquine that regulate ROS and related molecular pathways in increasing CP sensitivity are described. Nanoparticles can provide co-delivery of CP with anti-tumor agents and by mediating photodynamic therapy, and induce ROS overgeneration to trigger CP sensitivity. Genetic tools, such as small interfering RNA (siRNA) can down-regulate molecular pathways such as HIF-1α and Nrf2 to promote ROS levels, leading to CP sensitivity. Considering the relationship between ROS and CP chemotherapy, and translating these findings to clinic can pave the way for effective treatment of cancer patients.

Role of tumour location and surgical extent on prognosis in T2 gallbladder cancer: an international multicentre study

BACKGROUND

In gallbladder cancer, stage T2 is subdivided by tumour location into lesions on the peritoneal side (T2a) or hepatic side (T2b). For tumours on the peritoneal side (T2a), it has been suggested that liver resection may be omitted without compromising the prognosis. However, data to validate this argument are lacking. This study aimed to investigate the prognostic value of tumour location in T2 gallbladder cancer, and to clarify the adequate extent of surgical resection.

METHODS

Clinical data from patients who underwent surgery for gallbladder cancer were collected from 14 hospitals in Korea, Japan, Chile and the USA. Survival and risk factor analyses were conducted.

RESULTS

Data from 937 patients were available for evaluation. The overall 5-year disease-free survival rate was 70·6 per cent, 74·5 per cent for those with T2a and 65·5 per cent among those with T2b tumours (P = 0·028). Regarding liver resection, extended cholecystectomy was associated with a better 5-year disease-free survival rate than simple cholecystectomy (73·0 versus 61·5 per cent; P = 0·012). The 5-year disease-free survival rate was marginally better for extended than simple cholecystectomy in both T2a (76·5 versus 66·1 per cent; P = 0·094) and T2b (68·2 versus 56·2 per cent; P = 0·084) disease. Five-year disease-free survival rates were similar for extended cholecystectomies including liver wedge resection versus segment IVb/V segmentectomy (74·1 versus 71·5 per cent; P = 0·720). In multivariable analysis, independent risk factors for recurrence were presence of symptoms (hazard ratio (HR) 1·52; P = 0·002), R1 resection (HR 1·96; P = 0·004) and N1/N2 status (N1: HR 3·40, P < 0·001; N2: HR 9·56, P < 0·001). Among recurrences, 70·8 per cent were metastatic.

CONCLUSION

Tumour location was not an independent prognostic factor in T2 gallbladder cancer. Extended cholecystectomy was marginally superior to simple cholecystectomy. A radical operation should include liver resection and adequate node dissection.

Antihyperglycemic and Antiobesity Effects of JAL2 on db/db Mice

Lonicera japonica Thunb. (LJT) and Rehmannia glutinosa Libosch. (RGL) have been used traditionally as a herbal medicine in Korean medicine. Using LC/Q-TOF was performed to profile the two herbal medicines and the mixture of LJR and RGL (JAL2, ratio 1 : 1). We performed oral glucose tolerance test (OGTT) and plasma GLP-1 and insulin secretion by multiplex assays to investigate antidiabetic effects of LJT, RGL, and JAL2 in db/db mice, the mice model of type 2 diabetes mellitus (T2DM). Also, the antiobesity-related factors such as plasma peptide YY (PYY), triglyceride, total cholesterol, HDL, LDL, and weight of liver, epididymal, and retroperitoneal fat tissue were investigated. Through the multiplex assay, it was found that JAL2 treatment more efficiently attenuated high levels of blood glucose by stimulating GLP-1 secretion and reduced LDL concentration and weight of liver and retroperitoneal fat tissue compared to LJT or RGL treated separately. These results suggest that the JAL2 has antidiabetes and antiobesity effects in T2DM mice model.

Strain elastography features of epidermoid tumours in superficial soft tissue: differences from other benign soft-tissue tumours and malignant tumours

OBJECTIVE

We evaluated ultrasonographic features of superficial epidermoid tumour with a focus on strain elastography (SE) features that will help in the differential diagnosis of epidermoid tumour from other benign and malignant soft-tissue tumours.

METHODS

We retrospectively evaluated ultrasonographic and SE data of 103 surgically confirmed superficial soft-tissue tumours and tumour-like lesions: 29 cases of epidermoid tumour, 46 cases of other benign tumours and 28 cases of malignant tumour. SE and B-mode imaging were performed at the same time. SE characteristics were assigned into four grades (1-4) according to their elasticity. Interobserver agreement for the four SE scores between the two radiologists was analysed using kappa statistics. We classified each SE finding as a hard lesion (SE Score 3-4) or soft lesion (SE Score 1-2) and compared these findings using the χ(2) test to identify whether a significant difference in mass hardness existed among epidermoid tumour, other benign tumour and malignant tumour.

RESULTS

Overall interobserver agreement according to the four SE scores was moderate (κ = 0.540), and overall agreement for the hardness [soft (Score 1-2) or hard (Score 3-4)] was almost perfect (κ = 0.825). Malignant tumours showed higher SE scores (3-4, hard nature) than did epidermoid tumour or other benign soft-tissue tumours. There were no differences in SE score between epidermoid tumour and other benign tumours.

CONCLUSION

Superficial epidermoid tumour exhibits a softer nature than does malignant tumour but does not have a different SE pattern from other benign tumours.

ADVANCES IN KNOWLEDGE

SE features of epidermoid tumour might be helpful in differentiating from other benign and malignant tumours.

Negative regulation of signal transducer and activator of transcription-3 signalling cascade by lupeol inhibits growth and induces apoptosis in hepatocellular carcinoma cells

Background:

Constitutive activation of signal transducer and activator of transcription signalling 3 (STAT3) has been linked with survival, proliferation and angiogenesis in a wide variety of malignancies including hepatocellular carcinoma (HCC).

Methods:

We evaluated the effect of lupeol on STAT3 signalling cascade and its regulated functional responses in HCC cells.

Results:

Lupeol suppressed constitutive activation of STAT3 phosphorylation at tyrosine 705 residue effectively in a dose- and time-dependent manner. The phosphorylation of Janus-activated kinases (JAKs) 1 and 2 and Src was also suppressed by lupeol. Pervanadate treatment reversed the downregulation of phospho-STAT3 induced by lupeol, thereby indicating the involvement of a phosphatase. Indeed, we observed that treatment with lupeol increased the protein and mRNA levels of SHP-2, and silencing of SHP-2 abolished the inhibitory effects of lupeol on STAT3 activation. Treatment with lupeol also downregulated the expression of diverse STAT3-regulated genes and decreased the binding of STAT3 to VEGF promoter. Moreover, the proliferation of various HCC cells was significantly suppressed by lupeol, being associated with substantial induction of apoptosis. Depletion of SHP-2 reversed the observed antiproliferative and pro-apoptotic effects of lupeol.

Conclusions:

Lupeol exhibited its potential anticancer effects in HCC through the downregulation of STAT3-induced pro-survival signalling cascade.

A gene-specific primer extension and liquid bead array system for killer-cell immunoglobulin-like receptor genotyping

A simple and accurate method for killer-cell immunoglobulin-like receptor (KIR) genotyping is developed using KIR gene-specific primer extension (GSPE) followed by bead array hybridization (GSPE method). After amplification of exons 4, 5, and 9, KIR GSPE and bead array hybridization were performed to verify the presence or absence of 16 KIR subfamilies. GSPE method was validated with natural killer/KIR reference panel I consisting of 48 cell types provided by 13th International Histocompatibility Working Group (IHWG) and genomic DNA from 17 peripheral blood cells, 8 cell lines, and 8 buccal cells. The results of reference panel from GSPE method were 100% concordant with the IHWG reference typing information. All genomic DNAs except reference panel were typed for KIR genes with sequence-specific primer methods and showed 100% identical typing results using this novel system. In addition, GSPE method can obtain results in 8 h from DNA with 10 ng genomic DNA in a 96-well-based assay format.

Preoperative inflammation is a prognostic factor for gallbladder carcinoma

BACKGROUND

Inflammation frequently accompanies gallbladder carcinoma (GBC), but its impact on outcome is unclear. The present study investigated the impact of concomitant inflammation on survival of patients with GBC.

METHODS

All patients undergoing surgery for GBC between October 2003 and May 2009 were identified retrospectively from a prospectively collected database. Patients were classified according to whether preoperative inflammation was present (65 patients) or not (23).

RESULTS

A total of 88 patients were enrolled. There were no differences in sex, mean age, tumour node metastasis (TNM) stage and radicality of resection between the two groups. The overall 3-year survival rate was lower in patients with preoperative inflammation than in those without (33 versus 73 per cent; P = 0·001). In univariable analysis, preoperative inflammation, T, N and M category, TNM stage, radicality of surgery and tumour differentiation were significant prognostic factors. The presence of preoperative inflammation (hazard ratio (HR) 2·38, 95 per cent confidence interval 1·04 to 5·43), lymph node metastases (HR 5·23, 1·05 to 26·09) and R1 or R2 resection (HR 3·77, 1·47 to 9·72) were independent prognostic factors for poor survival.

CONCLUSION

The presence of preoperative inflammation is an independent prognostic factor for poor survival in patients with GBC.

Autoantibodies to glucose‐6‐phosphate isomerase are elevated in the synovial fluid of rheumatoid arthritis patients

OBJECTIVE

This study investigated whether anti-glucose-6-phosphate isomerase (GPI) antibody in the synovial fluid is specifically related to human rheumatoid arthritis (RA).

METHODS

Synovial fluid was collected from patients with RA, osteoarthritis (OA), gout, Behcet's disease, or ankylosing spondylitis. GPI-binding activity was measured in the synovial fluid using a surface plasmon resonance (SPR) biosensor.

RESULTS

The mean level of anti-GPI signal in the synovial fluid of RA patients was significantly elevated compared with that of OA patients (2.84 +/- 1.41 AU versus 1.19 +/- 0.42 AU, respectively; p < 0.0001). Anti-GPI signals in the synovial fluids of patients with non-rheumatoid arthritis, such as gout, Behcet's disease, or ankylosing spondylitis were significantly lower than in the synovial fluid of RA patients (p < 0.005), and were similar to those of OA patients.

CONCLUSION

Our study indicates that anti-GPI antibody in the synovial fluid is specifically related to RA, and suggests that GPI and its autoantibody might be important in the pathogenesis of human RA.

Patency of splenic vessels after laparoscopic spleen and splenic vessel-preserving distal pancreatectomy

Background

This study evaluated the short- and long-term patency of preserved splenic vessels after laparoscopic spleen-preserving distal pancreatectomy (SPDP) with preservation of the splenic vessels.

Methods

This single-centre retrospective study included all patients who had undergone splenic vessel-preserving laparoscopic SPDP between 2004 and 2007. The patency of the splenic vessels was assessed by abdominal computed tomography and classified into three grades according to the degree of stenosis.

Results

Twenty-two patients were included. The preoperative patency of the splenic artery and vein was normal in 20 and 19 patients respectively. Normal patency of the splenic artery and vein was observed in 16 and five patients respectively within 1 month of surgery, and in 19 and nine patients 6 months or more after operation. Nine of ten patients with complete splenic vein occlusion developed a collateral circulation in the late postoperative phase. Splenic perfusion was well preserved in all patients.

Conclusion

Splenic vessel-preserving laparoscopic SPDP has the short-term benefit of good perfusion to the spleen. In the long term, there is a risk of left-sided portal hypertension if the splenic vein becomes occluded after surgery.

Case of adult mumps infection after renal transplantation

Viruses are the most common cause of opportunistic infections, important complications of transplantation. Mumps infection in renal transplant recipients is uncommon. This report focused on a 23-year-old woman who received immunosuppressive therapy based on tacrolimus, prednisolone, and mycophenolate mofetil for renal transplantation. Sixteen months after transplantation, she was admitted with pain and swelling in both infra-auricular areas. Laboratory findings demonstrated positive mumps IgM and IgG antibodies and an increased serum amylase level. Computed tomography revealed both parotid glands to be diffusely enlarged. After the diagnosis of mumps parotitis, the patient's immunosuppression was reduced and the clinical course was satisfactory.

Epidermal growth factor (EGF) activates nuclear factor-κB through IκBα kinase-independent but EGF receptor-kinase dependent tyrosine 42 phosphorylation of IκBα

Overexpression of epidermal growth factor (EGF) receptor and constitutive activation of nuclear factor-kappaB (NF-kappaB) are frequently encountered in tumor cells. Although EGF has been shown to induce NF-kappaB activation, the mechanism is poorly understood. EGF activated NF-kappaB DNA binding, induced NF-kappaB reporter activity and the expression of antiapoptotic and cell-proliferative gene products. Interestingly, non-small cell lung adenocarcinoma cell lines (HCC827 and H3255), which exhibit EGFR amplification, showed ligand-independent activation of NF-kappaB. Unlike tumor-necrosis factor (TNF), however, EGF failed to induce IkappaBalpha phosphorylation and ubiquitination and the activation of IkappaBalpha kinase (IKK). Although DN-IKKbeta inhibited TNF-induced NF-kappaB activity, DN-IKKbeta had no effect on EGF-induced NF-kappaB activation, suggesting that EGF-induced NF-kappaB activation is IKK independent. Using dominant-negative plasmids, we also demonstrated the role of TRADD, TRAF2, NIK and Ras in EGF-induced NF-kappaB activation. By using specific antibodies and IkappaBalpha plasmid, which is mutated at tyrosine 42 to phenylalanine, we show that EGF induced the tyrosine phosphorylation of IkappaBalpha at residue 42. Furthermore, EGF receptor kinase inhibitor blocked IkappaBalpha phosphorylation and consequent NF-kappaB activation. Overall, our results indicate that tyrosine phosphorylation of IkappaBalpha at residue 42 is critical for EGF-induced NF-kappaB activation pathway.

The effects of curcumin on the invasiveness of prostate cancer in vitro and in vivo

Curcumin has become a focus of interest with regard to its antitumor effects in prostate cancer; however, the effects of this agent on invasion and metastasis remain less well understood. Matrix metalloproteinases (MMPs) are important prerequisite for tumor invasion and metastasis. In this study, we evaluated the effects of curcumin on prostate cancer cells (DU-145) invasion in both in vitro and in vivo. We utilized zymography and ELISA in order to determine the MMP-2 and MMP-9 activity. Matrigel invasion assay was performed to assess cellular invasion. We developed a xenograft model to examine tumorigenicity. Curcumin treatment resulted not only in a significant reduction in the expression of MMP-2 and MMP-9, but also effected the inhibition of invasive ability in vitro. Curcumin was shown to induce a marked reduction of tumor volume, MMP-2, and MMP-9 activity in the tumor-bearing site. The metastatic nodules in vivo were significantly fewer in the curcumin-treated group than untreated group. Curcumin appears to constitute a potential agent for the prevention of cancer progression, or at least of the initial phase of metastasis, in prostate cancer.

TNF blockade: an inflammatory issue

Tumor necrosis factor (TNF), initially discovered as a result of its antitumor activity, has now been shown to mediate tumor initiation, promotion, and metastasis. In addition, dysregulation of TNF has been implicated in a wide variety of inflammatory diseases including rheumatoid arthritis, Crohn's disease, multiple sclerosis, psoriasis, scleroderma, atopic dermatitis, systemic lupus erythematosus, type II diabetes, atherosclerosis, myocardial infarction, osteoporosis, and autoimmune deficiency disease. TNF, however, is a critical component of effective immune surveillance and is required for proper proliferation and function of NK cells, T cells, B cells, macrophages, and dendritic cells. TNF activity can be blocked, either by using antibodies (Remicade and Humira) or soluble TNF receptor (Enbrel), for the symptoms of arthritis and Crohn's disease to be alleviated, but at the same time, such treatment increases the risk of infections, certain type of cancers, and cardiotoxicity. Thus blockers of TNF that are safe and yet efficacious are urgently needed. Some evidence suggests that while the transmembrane form of TNF has beneficial effects, soluble TNF mediates toxicity. In most cells, TNF mediates its effects through activation of caspases, NF-kappaB, AP-1, c-jun N-terminal kinase, p38 MAPK, and p44/p42 MAPK. Agents that can differentially regulate TNF expression or TNF signaling can be pharmacologically safe and effective therapeutics. Our laboratory has identified numerous such agents from natural sources. These are discussed further in detail.

Inhibitory effect of cyclo-oxygenase-2 inhibitor on the production of matrix metalloproteinases in rheumatoid fibroblast-like synoviocytes

Cyclo-oxygenase (COX)-2 has been associated with inflammation in rheumatoid arthritis (RA), but its role in joint destruction remains unclear. In this study, we investigated the effect on cultured rheumatoid fibroblast-like synoviocytes (FLS) of the selective COX-2 inhibitor celecoxib on the expression of matrix metalloproteinases (MMPs), which play an important role in tissue degradation and angiogenesis in rheumatoid synovium. Treatment with nontoxic doses of celecoxib resulted in dose-dependent inhibition of MMP-1, -2, and -3 secretion from FLS when measured by enzyme-linked immunosorbent assay. Celecoxib suppressed proinflammatory cytokines (tumor necrosis factor-alpha and interleukin-1beta) induced augmentation of the gelatinolytic activity on zymography. These results suggest that COX-2 inhibitors might influence matrix degradation or angiogenesis in RA by downregulating the expression of various MMPs in rheumatoid FLS.

Influence of hypoxia on the expression of matrix metalloproteinase-1, -3 and tissue inhibitor of metalloproteinase-1 in rheumatoid synovial fibroblasts

OBJECTIVE

The rheumatoid synovium is a hypoxic environment, and hypoxia has been implicated as a factor in the pathogenesis of rheumatoid arthritis (RA). The purpose of this study was to investigate the effect of hypoxia on the expression of matrix metalloproteinase (MMP)-1, -3 and tissue inhibitor of metalloproteinase (TIMP)-1 in rheumatoid synovial fibroblasts.

METHODS

Synovial fibroblasts obtained from RA patients were cultured for 48 h under normoxic or hypoxic conditions. Assays included western blot analysis and enzyme-linked immunosorbent assay (ELISA) for MMP-1, -3 and TIMP-1, and northern blot analysis to measure TIMP-1 mRNA levels.

RESULTS

Compared with normoxic culture, hypoxia increased MMP-1 and MMP-3 expression in rheumatoid synovial fibroblasts. Hypoxia decreased TIMP-1 expression in rheumatoid synovial fibroblasts, as measured by both protein and mRNA levels.

CONCLUSION

These results suggest that microenvironmental conditions, such as hypoxia, may directly contribute to joint destruction in RA by increasing the ratio of MMP-1, -3 to TIMP-1 production in synovial fibroblasts.

Effects of Korean red ginseng and its mixed prescription on the high molecular weight dextran-induced blood stasis in rats and human platelet aggregation

This study was undertaken to evaluate the antithrombotic effects of Korean Red Ginseng (KRG) and its new prescription (KRGP) consisting of five herbs such as Korean red ginseng, Ganoderma, Cinnamomi Cortex, Glycyrrhizae Radix and Laminaria. In rats with blood stasis induced by high molecular weight dextran, KRG and KRGP significantly restored not only the number of platelets and fibrinogen, but also suppressed the fibrin degradation products (FDP) to normal range. In platelet aggregation assay with human platelet rich plasma (PRP), KRG and KRGP significantly inhibited thrombin and collagen-induced platelet aggregation. The IC(50) values of KRG and KRGP were >2 and 0.23+/-0.01 mg/ml for thrombin, 0.32+/-0.01 and 0.17+/-0.02 mg/ml for collagen and 0.72+/-0.25 and >2 mg/ml for ADP, respectively. In coagulation assay, KRG and KRGP significantly prolonged activated partial prothrombin time (APPT) and prothrombin time (PT) as compared with control data. KRGP was found to be more effective than KRG alone on antithrombotic activity. These results suggest that KRGP may exert its antithrombotic activity due to inhibition of platelet aggregation and coagulation activity more than KRG.

Inhibitory activity of lignan components from the flower buds of Magnoliae fargesii on the expression of cell adhesion molecules

Inhibitory activity of lignans isolated from Magnoliae fargesii Cheng on cell adhesion molecules on the surface of THP-1 human monocytic cell lines were investigated. Among 16 lignan components tested, six displayed relatively potent inhibitory activity on the expression of both intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1).

Kojic acid, a potential inhibitor of NF-kappaB activation in transfectant human HaCaT and SCC-13 cells

The activation of NF-kappaB induced by kojic acid, an inhibitor of tyrosinase for biosynthesis of melanin in melanocytes, was investigated in human transfectant HaCaT and SCC-13 cells. These two keratinocyte cell lines transfected with pNF-kappaB-SEAP-NPT plasmid were used to determine the activation of NF-kappaB. Transfectant cells release the secretory alkaline phosphatase (SEAP) as a transcription reporter in response to the NF-kappaB activity and contain the neomycin phosphotransferase (NPT) gene for the dominant selective marker of geneticin resistance. NF-kappaB activation was measured in the SEAP reporter gene assay using a fluorescence detection method. Kojic acid showed the inhibition of cellular NF-kappaB activity in both human keratinocyte transfectants. It could also downregulate the ultraviolet ray (UVR)-induced activation of NF-kappaB expression in transfectant HaCaT cells. Moreover, the inhibitory activity of kojic acid in transfectant HaCaT cells was found to be more potent than known antioxidants, e.g., vitamin C and N-acetyl-L-cysteine. These results indicate that kojic acid is a potential inhibitor of NF-kappaB activation in human keratinocytes, and suggest the hypothesis that NF-kappaB activation may be involved in kojic acid induced anti-melanogenic effect.

Novel mutations of the transglutaminase 1 gene in lamellar ichthyosis

Lamellar ichthyosis, one form of congenital autosomal recessive ichthyosis, is caused by mutations in the gene (TGM1) encoding the transglutaminase 1 enzyme. Mutations, deletions, or insertion of TGM1 have been reported so far. Here we report that three novel mutations of TGM1, D101V, N288T, and R306W, cause lamellar ichthyosis in two different families. The patient in family LI-KD has N288T and R306W mutations, and the patient in family LI-LK has D101V and R306W mutations. The activity of the transglutaminase 1 enzyme of the patient in family LI-LK was only about 15% of normal. Also, three-dimensional structural prediction analyses revealed that the N288T and R306W mutations, and possibly the D101V mutation, cause misfolding in the central catalytic core domain of the transglutaminase 1 enzyme that would probably result in reduced enzyme activity. Our data suggest that the greatly reduced transglutaminase 1 activities are due to disruptions of the native folding of transglutaminase 1, and that these mutations may play a critical role in the pathology of lamellar ichthyosis.

In vitro establishment of cis-diammine-dichloroplatinum(II) resistant lung cancer cell line and modulation of apoptotic gene expression as a mechanism of resistant phenotype

After exposure of H460 cells to an increasing concentrations of cis-diammine-dichloroplatinum(II) (cisplatin, CDDP) for 6 months, cisplatin resistant cells were isolated (H460/CIS). The biologic behaviors of H460 and H460/CIS cells were tested using animal experiments. Only the resistant cells developed lung metastases despite cisplatin treatment. The characteristics of H460/CIS cells are as follows, MTT analyses revealed that H460/CIS cells were markedly resistant to cisplatin compared with their parental cells. Also, H460/CIS cells exhibited cross-resistance to DNA damaging agents such as doxorubicin (DXR) and etoposide. Cisplatin treatment dramatically increased p53 expression in parental cells but not in H460/CIS cells which expressed basal levels of p53. Without cisplatin treatment, Bcl-2 and Bax were expressed in H460/CIS cells, but not in parental cell. Our data suggested that p53, Bax and Bcl-2 were up-regulated in H460/CIS cells. These changes could explain some of the mechanisms of cisplatin resistance. Thus, H460/CIS could be useful to investigate the mechanisms of drug resistance to cisplatin including apoptotic gene expressions conferring drug resistance, thereby making progress in the treatment of cisplatin-resistant tumor cells.

Semialactone, isofouquierone peroxide and fouquierone, three new dammarane triterpenes from Rhus javanica

Three new dammarane triterpenes and semialactic acid were isolated from the stem bark of Rhus javanica. The structures of these triterpenes, named semialactone, isofouquierone peroxide and fouquierone, were elucidated by 2D-NMR analysis (HMQC, 1H-1H COSY and HMBC), and the 13C-NMR data of semialatic acid is revised.

Inhibitory effect of glycolic acid on ultraviolet-induced skin tumorigenesis in SKH-1 hairless mice and its mechanism of action

Glycolic acid, an alpha-hydroxy acid derived from fruit and milk sugars, has been used commonly as a cosmetic ingredient since it was discovered to have photoprotective and anti-inflammatory effects and antioxidant effects on ultraviolet (UV)B-irradiated skin. Little is known, however, about the functional role of glycolic acid on UV-induced skin tumorigenesis. In the present study, we examined the effect of glycolic acid on UV (UVA + UVB)-induced skin tumorigenesis and assessed several significant contributing factors in SKH-1 hairless mice. Inbred hairless female mice (15 animals/group) were irradiated for 5 d/wk at a total dose of 74.85 J/cm(2) UVA and 2.44 J/cm(2) UVB for 22 wk. Glycolic acid was applied topically twice a week at a dose of 8 mg/cm(2) immediately after UV irradiation. Glycolic acid reduced UV-induced skin tumor development. The protective effect of glycolic acid was a 20% reduction of skin tumor incidence, a 55% reduction of tumor multiplicity (average number of tumors/mouse), and a 47% decrease in the number of large tumors (larger than 2 mm). Glycolic acid also delayed the first appearance of tumor formation by about 3 wk. The inhibitory effect of glycolic acid on UV-induced tumor development was accompanied by decreased expression of the following UV-induced cell-cycle regulatory proteins: proliferating cell nuclear antigen (PCNA), cyclin D1, cyclin E, and the associated subunits cyclin-dependent kinase 2 (cdk2) and cdk4. In addition, the expression of p38 kinase, jun N-terminal kinase (JNK), and mitogen-activated protein kinase kinase (MEK) also was lower in UV + glycolic acid-treated skin compared with expression in UV-irradiated skin. Moreover, transcription factors activator protein 1 (AP-1) and nuclear factor kappaB (NF-kappaB) activation was significantly lower in UV + glycolic acid-treated skin compared with activation in UV-irradiated skin. These results show that glycolic acid reduced UV-induced skin tumor development. The decreased expression of the cell-cycle regulatory proteins PCNA, cyclin D1, cyclin E, cdk2, and cdk4 and the signal mediators JNK, p38 kinase, and MEK may play a significant role in the inhibitory effect of glycolic acid on UV-induced skin tumor development. In addition, the inhibition of activation of transcription factors AP-1 and NF-kappaB could contribute significantly to the inhibitory effect of glycolic acid.

Behavior of murine renal carcinoma cells grown in ectopic or orthotopic sites in syngeneic mice

We examined whether the organ microenvironment modulates the metastatic behavior and the response to doxorubicin (DXR) in murine renal carcinoma (RENCA) cells. Tumor cells were injected into kidney (orthotopic) and subcutis (ectopic) of syngeneic mice. Lung metastases developed in up to 57% (17/30) of animals having kidney tumors but not in those with skin tumors. Tumors growing in the kidney were more resistant to DXR than tumors growing in the subcutis when mice were given intravenous injections of DXR (8 mg/kg) on days 8 and 15 after implantation. In addition, tumor cells cultured from kidney tumors were initially more resistant to DXR than tumor cells cultured from subcutis tumors. After tumor cells were passaged in vitro, all cells exhibited a similar sensitivity to DXR. Additionally, we examined the expression levels of mdr1, EGFR and type IV collagenase by an in situ mRNA hybridization technique. A higher mRNA expression for type IV collagenase and EGFR was found in kidney tumors than in subcutis tumors. These results demonstrate that the organ environment influences the drug responsiveness and the expression of metastasis-related genes in murine renal carcinoma cells.

Activation of mitogen-activated protein kinase pathways by angelan in murine macrophages

In our previous studies, we showed that angelan, a polysaccharide purified from Angelica gigas Nakai, specifically activated macrophages to induce cytokines including inducible nitric oxide synthase (iNOS) which has strong anti-tumor activities [Immunopharmacology, 1999; 43: 1.]. In the present study, we investigated the intracellular signal transduction pathways involved in the angelan-induced iNOS synthesis by murine macrophages. Protein tyrosine phosphorylation was induced within 5 min by angelan, and the blocking of protein tyrosine kinases (PTKs) inhibited down-stream pathways leading to iNOS production in response to angelan. Treament of RAW 264.7 cells with angelan resulted in significant activation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) and p38, while stress-activated protein kinase/c-Jun NH2 terminal kinase (SAPK/JNK) was not activated by angelan. The specific p38 inhibitor SB203580 abrogated the angelan-induced iNOS synthesis, whereas the selective mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase 1 (MEK-1) inhibitor PD98059 did not affect the iNOS induction. In conclusion, we demonstrate that PTK and p38 MAPK activation are required to transduce signals leading to iNOS expression in angelan-stimulated murine macrophages.

Characterization of the 16S rRNA gene V2 region and the rrn operons of Gardnerella vaginalis

Ribosomal RNA (rRNA) gene polymorphism was apparent when Gardnerella vaginalis DNA restriction profiles were hybridized with nonradioactively labeled total rRNA isolated from this bacterium. In contrast, use of a polymerase chain reaction (PCR)-based 16S rRNA gene V2 region resulted in a 118-bp V2-PCR amplicon that was specific and common in all 30 tested G. vaginalis isolates. In addition to providing a G. vaginalis-specific fingerprint, when the V2-PCR amplicon along with total rRNA were utilized as probes, a partial rRNA gene restriction map could be constructed. G. vaginalis contains two rrn operons with an EcoRI fragment of 1.6 kb common to both.

Inhibitory activity of stilbenes from medicinal plants on the expression of cell adhesion molecules on THP1 cells

The inhibitory activity of stilbenes isolated from medicinal plants on cell adhesion molecules on the surface of THP-1 human monocytic cell lines was investigated. Among ten stilbenes tested, four stilbenes displayed a significant inhibitory activity on the expression of both intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). A cell-to-cell adhesion assay showed that 3,5-dihydroxy-4'-methoxystilbene and 2,3,4',5-tetrahydroxystilbene-2-O-beta-D-glucopyranoside as well as resveratrol blocked significantly TNF-alpha-inducing cell-cell adhesion between human umbilical vein endothelial cells (HUVEC) and THP-1 cells.

Differential activation of murine macrophages by angelan and LPS

In our previous studies, we showed that angelan, a polysaccharide purified from Angelica gigas Nakai, is a potent LPS-mimetic in murine macrophages [Jeon, Y.J., Han, S.B., Ahn, K.S., Kim, H.M., 1999. Activation of NF-kB/Rel in angelan-stimulated macrophages. Immunopharmacology 43, 1-9]. Angelan stimulates murine macrophage to produce cytokines including iNOS and activate NF-kappaB/Rel. In the present study, we investigated the role of CD14 and complement receptor type 3 (CR3) in mediating NO production and NF-kappaB/Rel activation induced by angelan and LPS. Three major differences between angelan and LPS were observed. First, angelan does not require serum proteins for NO response and NF-kappaB/Rel activation, while the activation by LPS requires serum proteins. Second, blocking of either CD14 or CR3 decreased angelan-induced NO response, while LPS-mediated NO production was inhibited by anti-CD14 mAb only. Third, angelan induced strong NF-kappaB/Rel and slight AP-1 DNA binding, whereas LPS potently activated both NF-kappaB/Rel and AP-1. Both angelan and LPS degraded IkappaB proteins and subsequently induced the mobilization of NF-kappaB/Rel proteins (p65, c-rel and p50) into nucleus. This suggests that macrophages display a common signaling machinery leading to the NF-kappaB/Rel activation in response to different stimulants. In conclusion, angelan and LPS use the membrane receptor CD14 and CR3 differentially for signaling NF-kappaB/Rel activation and NO production.

Effects of triterpenoids from Pueraria lobata on immunohemolysis: beta-D-glucuronic acid plays an active role in anticomplementary activity in vitro

The anticomplementary properties of kaikasaponin III (4) and soyasaponin I (8) from Pueraria lobata and their hydrolytic analogs were investigated in vitro. Diglycosidic saponins [kaikasaponin I (3), soyasaponin III (7)] showed most potent anticomplementary activities, followed by monoglycosidic saponins [soyasapogenol B monoglucuronide (6), sophoradiol monoglucuronide (2)] and triglycosidic saponins [soyasaponin I (8), kaikasaponin III (4)], whereas sophoradiol (1) and soyasapogenol B (5) showed enhancement of hemolysis under the presence of serum on the classical pathway of complement system. But all of them showed very weak or no anticomplementary activities on the alternative pathway of complement system. The anticomplementary activity of the saponins was influenced by the nature of glucuronic acid, where the free acid forms (-COOH) showed much more potent activity than the sodium salt forms (-COO-Na+) or methyl ester forms (-COOCH3), and the reduced forms (-CH2OH) decreased the activity significantly.

Enhanced induction of Bax gene expression in H460 and H1299 cells with the combined treatment of cisplatin and adenovirus mediated wt-p53 gene transfer

Cytotoxic effect of either cisplatin or p53 gene transfection of lung cancer cells may be different depending on the p53 status of cells. We investigated cytotoxic effects on the combined treatment of cisplatin and adenovirus mediated p53 gene transfer (Avp53) in both H460 and H1299 cells in vitro. The results showed the highest numbers of apoptotic cells in both H460 and H1299 cells following the combined treatment regardless of p53 status in comparison with either cisplatin or Avp53 alone. The expression levels of p53, p21, Bax and ICE were examined to understand a possible cellular signal path of the combined treatment. In western analyses, the patterns of phosphorylated p53 protein were different between Avp53 and combined treatment. The expressions of p21 and Bax were increased in combined treatment, whereas the cleaved form of ICE (20 kD) was not detected. These results suggest that cisplatin induced p53 protein phosphorylation and may activate the downstream of p53 gene expression such as p21 and Bax. The enhanced apoptosis of lung cancer cells by the combined treatment may be useful in the development of clinical therapeutic modality of lung tumors.

Cloning, nucleotide sequence and expression of thioltransferase (glutaredoxin) cDNA from Schizosaccharomyces pombe

Thioltransferase (TTase), also known as glutaredoxin (Grx), is an enzyme that catalyzes the reduction of a variety of disulfide compounds, including protein disulfides, in the presence of reduced glutathione. TTase acts as a cofactor for various enzymes such as ribonucleotide reductase. We previously purified a TTase from Schizosaccharomyces pombe and its molecular size was determined. In the present study, a cDNA coding TTase was isolated from a cDNA library of Schizosaccharomyces pombe by colony hybridization, which was constructed in a plasmid vector pGAD GH, and its corresponding insert was confirmed by Southern hybridization. The nucleotide sequence of the 375 bp long cDNA clone reveals an open reading frame, which encodes a protein of 101 amino acids. The coding region of the original clone was transferred after the lac promoter of pUC13 vector for expression in E. coli, and simultaneously, a suitable Shine-Dalgarno (SD) sequence was added in front of the coding region by PCR. The two primers used for PCR also separately contained BamHI and HindIII restriction sites. The E. coli strain (A434) harboring the pUC13 derivative pKU10 showed a 17.3-fold increase in TTase activity compared to the strain with only the vector plasmid.

Acylated flavonol glycosides with anti-complement activity from Persicaria lapathifolia

During a search for biologically active compounds from traditional medicines, a crude extract of Persicaria lapathifolia was found to have anti-complement activity. Bioassay-guided chromatographic separation of the active constituents led to the isolation of a new acylated kaempferol glycoside (1) and three known acylated quercetin glycosides (2-4). The structures of compounds 1-4 were characterized as kaempferol 3-O-beta-D-(6"-p-hydroxybenzoyl)-galactopyranoside, quercetin 3-O-beta-D-(6"-feruloyl)-galactopyranoside, quercetin 3-O-beta-D-(2"-galloyl)-rhamnopyranoside and quercetin 3-O-beta-D-(2"-galloyl)-glucopyranoside, respectively. Compounds 1-4 showed strong anti-complement activity (IC50 values of 4.3, 9.7, 3.9 and 7.6 x 10(-5) M, respectively) on the classical pathway of the complement. On the other hand, six isolated flavonol glycosides (5-10) did not show any activity on this system.

Anticomplement activities of oleanolic acid monodesmosides and bisdesmosides isolated from Tiarella polyphylla

Seven known oleanolic acid glycosides (1-7) were isolated from the MeOH extract of Tiarella polyphylla. The structures were identified to be 3-O-(beta-D-glucopyranosyl) oleanolic acid (1), 3-O-[beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl] oleanolic acid (2), 3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl] oleanolic acid (3), 3-O-[beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl] oleanolic acid 28-O-beta-D-glucopyranosyl ester (4), 3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl] oleanolic acid 28-O-beta-D-glucopyranosyl ester (5), 3-O-[a-L-rhamnopyranosyl-(1-->3)-beta-D-glucuronopyranosyl] oleanolic acid (6), and 3-O-[alpha-L-rhamnopyranosyl-(1-->3)-beta-D-glucuronopyranosyl] oleanolic acid 28-O-beta-D-glucopyranosyl ester (7) on the basis of physicochemical and spectral data. These triterpene glycosides were tested for the anticomplement activity and hemolytic activity. Bisdesmosidic saponins, 4, 5, and 7, showed anticomplement activity; in contrast, monodesmosidic saponins, 1-3, and 6, showed direct hemolytic activity. Methyl esterified monodesmosidic saponins showed anticomplement activity at a low concentration and hemolytic activity at a high concentration.

In vitro anticomplementary activity of hederagenin saponins isolated from roots of Dipsacus asper

Anticomplementary activity of hederagenin and related saponins isolated from Dipsacus asper was investigated in vitro. HN saponin F (3) was most potent with IC50 value of 3.7x10(-5) M followed by 3-O-beta-D-glucopyranosyl-(1->3)-alpha-L-rhamnopyranosyl-(1->2)-beta-L-+ ++arabi nopyranosyl hederagenin 28-O-beta-D-glucopyranosyl-(1->6)-beta-D-glucopyrano side (8), 3-O-beta-L-arabinopyranosyl hederagenin 28-O-beta-D-glucopyranosyl-(1->6)-beta-D-glucopyranoside (5), dipsacus saponin A (4), and hederagenin (1) on the classical pathway (CP) of complement system, while the saponins 3-5 did not show the inhibition of hemolysis and rather increase the hemolysis on the alternative pathway (AP). However, all of C-3 monodesmosides [prosapogenin CP (2), dipsacus saponin B (6), and dipsacus saponin C (7)] evoked hemolysis directly on the erythrocytes.

Activation of NF-kappaB/Rel in angelan-stimulated macrophages

In our previous studies we showed that the primary target cell of angelan, a polysaccharide purified from Angelica gigas Nakai, is a macrophage (Han et al., 1998). In the present study we examined the effect of angelan on iNOS, IL-1beta, and TNF-alpha transcription in mouse macrophage line RAW 264.7. We show that angelan produces a marked induction of iNOS, IL-1beta, and TNF-alpha transcription by RAW 264.7 cells. Since these gene transcriptions have been recently shown to be under the control of NF-kappaB/Rel family of transcription factors, we assessed the effect of angelan on NF-kappaB/Rel using a electrophoretic mobility shift assay. Treatment of RAW 264.7 cells with angelan produced strong induction of NF-kappaB/Rel binding. Treatment of RAW 264.7 cells with angelan slightly induced AP-1 binding activity, whereas Oct binding was not affected by angelan. Angelan stimulated macrophages to activate NF-kappaB/Rel, whereas neither B-cells nor T-cells were affected by the angelan. In conclusion, we demonstrate that the stimulation effect of angelan on macrophage is mediated by specific activation of NF-kappaB/Rel.

Structure-activity relationships of lignans from Schisandra chinensis as platelet activating factor antagonists

We studied the structure-activity relationships of lignans from Schisandra chinensis and their derivatives as platelet activating factor (PAF) antagonists. Strong activity was shown in lignans without an ester group at C-6, a hydroxyl group at C-7 or a methylene dioxy moiety and with an R-biphenyl configuration. 6(7)-Dehydroschisandrol A, a derivative of schisandrol A, showed the highest activity (IC50, 2.1x10(-6) M) in this study.

Anti-complement activity of tiliroside from the flower buds of Magnolia fargesii

As part of the search for anticomplementary active components from natural products, the anticomplementary properties of methanolic extracts from the flower buds of Magnoliafargesii have been investigated. Bioassay-guided chromatographic separation of the active constituents led to the isolation of compound 1, whose structure was identified by spectroscopic methods to be kaempferol 3-O-beta-D-(6"-O-coumaroyl)glucopyranoside (tiliroside). Tiliroside showed very potent anti-complement activity (IC50=5.4 x 10(-5) M) on the classical pathway of the complement system, even higher than rosmarinic acid, which is a well-known inhibitor against the complement system. On the other hand, the hydrolysates of tiliroside, kaempferol, astragalin and p-coumaric acid showed very weak activity on this system.

Characteristic immunostimulation by angelan isolated from Angelica gigas Nakai

The immunopharmacological characteristics of angelan, a polysaccharide purified from Angelica gigas Nakai, were investigated in relation to the specificity to immune cells. The treatment of angelan increased the expression of IL-2, IL-4, IL-6, and IFN-gamma. The expression of IL-6 and IFN-gamma was rapidly augmented but that of IL-2 responded later. In the case of IL-4, angelan stimulated at early time after exposure but down-regulated thereafter. These results suggested that macrophages and natural killer cells involved in nonspecific immunity were primarily activated and helper T cells were secondarily affected by angelan. Angelan also had lympho-proliferative potential to B cells, specifically. The specificity of angelan was also elucidated in a cell fractionation experiment. The activated B cells by angelan also increased antibody production. The direct activation of B cells, macrophages, and accessory cells and the indirect activation of helper T cells coordinately increased immune functions such as in vitro and in vivo T-dependent immunization and antibody production. The experiment of host resistance to syngeneic tumors also showed that angelan potentiated the immune functions. In conclusion, angelan, a purified polysaccharide from an oriental herbal drug, showed characteristic immunostimulation, which was different from clinically used polysaccharides such as lentinan and PSK.

Corosolic acid isolated from the fruit of Crataegus pinnatifida var. psilosa is a protein kinase C inhibitor as well as a cytotoxic agent

Corosolic acid isolated from the fruit of Cratoegus pinnatifida var. psilosa was tested for anticancer activity. Corosolic acid displayed about the same potent cytotoxic activity as ursolic acid against several human cancer cell lines. In addition, the compound displayed antagonistic activity against the phorbol ester-induced morphological modification of K-562 leukemic cells, indicating the suppression of protein kinase C (PKC) activity by the cytotoxic compound. The compound showed PKC inhibition with dose-dependent pattern in an in vitro PKC assay.

Decursinol angelate: a cytotoxic and protein kinase C activating agent from the root of Angelica gigas

A cytotoxic compound was purified from the root of Angelica gigas Nakai by normal phase HPLC. As a result of the structure analysis by mass, IR, 1H-NMR, and 13C-NMR spectrometry, the compound was identified as decursinol angelate, a structural isomer of decursin, and characterized originally from Sesei grandivittatum. Decursinol angelate showed in vitro cytotoxicity and protein kinase C activating activities like decursin.

Nucleotide sequence and developmental expression of Acanthamoeba S-adenosylmethionine synthetase gene

We have isolated and characterized a cDNA (cDNA1) from an Acanthamoeba cDNA library encoding the enzyme S-adenosylmethionine (SAM) synthetase (ATP: L-methionine S-adenosyltransferase; EC 2.5.1.6). The nucleotide sequence exhibits about 61-73% overall similarity to the corresponding gene of other organisms. The cDNA displays extreme codon bias with a preference for C or G in the third position. A putative initiation site and an ATP-binding site are identified. An amino acid content of 388 and a molecular mass of about 44,000 Daltons are deduced for the enzyme. Putative phosphorylation sites which might be involved in regulation of the enzyme are revealed. The cDNA was expressed in Escherichia coli BL21(DE3), and the identity of the protein product confirmed by Western blotting analysis. Northern analyses of the expression of the Acanthamoeba SAM synthetase gene during development revealed a pronounced reduction in the level of transcripts as amoebae converted to cysts.

Decursin: a cytotoxic agent and protein kinase C activator from the root of Angelica gigas

A cytotoxic compound was purified from the root of Angelica gigas Nakai by silica gel chromatography and preparative HPLC. As a result of the structure analysis by mass, IR, 1H-NMR, and 13C-NMR spectrometry, the effective compound was identified as decursin, a pyranocoumarin characterized originally from Angelica decursiva Fr. et Sav. In vitro cytotoxicity testing showed that decursin displayed toxic activity against various human cancer cell lines, for which the ED50 of decursin was about 5-16 micrograms/ml. On the other hand, decursin displayed relatively low cytotoxicity against normal fibroblasts. Decursin also activated protein kinase C (PKC) in vitro, which indicates that the cytotoxic activity of decursin may be related to the protein kinase C activation.

Electronic dental anesthesia versus topical anesthesia for the control of pain caused by nasopalatine block injections

Topical anesthetics are routinely used to reduce the pain and discomfort that patients may experience during dental injections. Just recently, however, an anesthesia (Electronic Dental Anesthesia or EDA) which works by transcutaneous electrical nerve stimulation (TENS) was introduced to the dental profession. The purpose of this study was to determine whether an electrical signal as provided by an EDA is more effective than topical anesthesia in reducing pain and discomfort caused by local anesthetic injections. Two nasopalatine block injections, one using and EDA as the adjunct, and the other using a topical anesthetic ointment of Xylocaine 5% were performed on thirty-four patients. The volunteers were asked on the spot to report the level of the pain they felt during the penetration of the needle to the mucosa, during the deposition of local anesthetic solution, and their overall evaluation of the injections. The results of this investigation showed that the EDA is the more effective adjunct for local anesthetic injections compared to the traditional topical anesthetics.

An Acanthamoeba ubiquitin-fusion protein; cDNA and deduced protein sequence

We have isolated and sequenced a 525 bp ubiquitin cDNA (Acantub1) from the soil amoeba Acanthamoeba castellanii. The deduced amino acid (aa) sequence reveals that the Acantub1 gene product is a fusion protein consisting of 128 aa (76 aa ubiquitin and 52 aa 60S ribosomal protein). The Acantub1 protein sequence has unique substitutions at aa 28 (glutamine for alanine) and 121 (tryptophan for leucine) compared to the 8 highest homologous sequences in the databank. A putative 'zinc finger' nucleic acid-binding domain was located in the 52 aa ribosomal protein. Northern analyses reveal that the Acantub1 gene is regulated during development.

Autoregulation of the gene encoding the replication terminator protein of Bacillus subtilis

One of two putative sigma A promoters identified previously in the region immediately upstream from the rtp gene (encoding the replication terminator protein) [Smith and Wake, J. Bacteriol. 170 (1988) 4083-4090] has been shown by transcription start point (tsp) mapping to be the functional rtp promoter. In these tsp mapping experiments, it was observed that the level of mRNA from this promoter, Prtp, was increased by a factor of 30 in the absence of the replication terminator protein (RTP), consistent with the autoregulation of rtp at the level of transcription. In vitro transcription from Prtp by sigma A RNA polymerase has been shown to be specifically repressed by RTP. A Prtp-spoVG-lacZ fusion was inserted into the chromosome of a strain in which RTP production was inducible by IPTG. Addition of IPTG to cultures of the new strain lowered beta Gal production by a factor of at least four. It is concluded that rtp is autoregulated in vivo at the level of transcription.

Variations and coding features of the sequence spanning the replication terminus of Bacillus subtilis 168 and W23 chromosomes

In a comparative study of the sequences of the 3-kb regions of DNA spanning the replication terminus, terC, of Bacillus subtilis strains 168 and W23, it was found that the latter contained an insertion of a large open reading frame (ORF405) whose translated protein product is a member of the cytochrome P-450 family. The insertion was about 34 nucleotides upstream from a putative promoter for the rtp gene. The sequenced regions contained a number of other ORFs. The translation product of one (ORF238) is a member of a previously identified oxidoreductase superfamily. The translation product of another (ORF257) is significantly similar to the proC product of Escherichia coli, but this ORF does not code for a functional proC product of B. subtilis.