The anti-tumor effects of Celastrus orbiculatus Thunb. and its monomer composition: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Celastrus orbiculatus Thunb. has been included in "The Plant List" (http://www. theplantlist.org) and is the most widely researched species in its genus. It is called Nanshe Teng in China. Celastrus orbiculatus Thunb. is a plant of Euonymus and it's medicinal part is the vine and stem. It is also called Alias Dragon grass, Yellow Yine, etc. It has good anti-tumor, anti-inflammatory and other effects. More and more studies have shown that Celastrus orbiculatus Thunb. has a significant therapeutic effect on a variety of malignant tumors. The research on Celastrus orbiculatus Thunb. has a good application prospect for the development of anti-tumor drugs. However, no systematic reports on Celastrus orbiculatus Thunb. have been published before.

AIM OF THE REVIEW

This paper summarizes the metabolic products for anti-tumor and the mechanism for anti-tumor of Celastrus orbiculatus Thunb. to provide reference for further development and research.

MATERIALS AND METHODS

The relevant information on Celastrus orbiculatus Thunb. was collected from the scientific databases including PubMed, CNKI, ScienceDirect, Wiley, Springer, Web of Science, Google Scholar, Baidu Scholar, Pharmacopoeia of the People's Republic of China and Flora Republicae Popularis Sinicae, etc. RESULTS: At present, more than 200 compounds have been identified from Celastrus orbiculatus Thunb., including terpenoids, flavonoids, phenylpropanoids, polyketides and benzene derivatives, etc. Pharmacological studies have shown that Celastrus orbiculatus Thunb. has a variety effects of inhibiting tumor cell proliferation, inducing tumor cell apoptosis, inhibiting tumor cells invasion, metastasis and angiogenesis, reversing multi-drug resistance, and also collaborativing Micro RNA to inhibit tumor growth, etc. It has a significant effect on gastric cancer, liver cancer, lung cancer, etc. The extracts of Celastrus orbiculatus Thunb. have been widely used in experiments, and the toxic and side effects are small.

CONCLUSIONS

Celastrus orbiculatus Thunb. is rich in chemical constituents, diverse in pharmacological activities and abundant in resources, which is widely used in clinics from traditional to modern. However, there is no systematic report on the chemical compounds and anti-tumor effects of Celastrus orbiculatus Thunb. We organize and summarize it to provide reference for further development and research.

Celastrus orbiculatus Thunb. extract inhibits EMT and metastasis of gastric cancer by regulating actin cytoskeleton remodeling

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional Chinese medicine herb Celastrus orbiculatus Thunb. is an important folk medicinal plant in China that has been used as an anti-inflammatory, antitumor, and analgesic in various diseases. Recent years, many studies have reported the significant effects of Celastrus orbiculatus Thunb. extract (COE) on gastric cancer. However, the specific mechanism by which COE regulates gastric cancer cytoskeleton remodeling and thus inhibits EMT has not yet been reported.

AIM OF STUDY

To study the effect and mechanism of COE in inhibiting the epithelial-mesenchymal transition (EMT) and metastasis of gastric cancer cells, laying an experimental foundation for the clinical application and further development of COE.

METHODS

The high-content cell dynamic tracking system was used to continuously track the trajectory of cell movement in real time. Through the high-content data, the average movement distance and movement speed of the cells are calculated. Additionally, the dynamic images of the cell movement in the high-content imaging system are derived to analyze the impact of COE on the movement of gastric cancer cells. Cytoskeleton staining experiment was performed to detect the effect of COE on the assembly of gastric cancer cell cytoskeleton proteins. Western blot was employed to detect the changes of EMT and metastasis-related proteins in the gastric cancer cells treated by COE. The effect of COE on the key regulatory protein Cofilin-1 (CFL1) of cell movement was examined by Western blot and protein degradation experiment. The effect of COE on EMT and metastasis of the gastric cancer cells lacking CFL1 was assessed by a transwell assay. The in vivo inhibitory effect of COE on EMT and metastasis of gastric cancer was determined by the animal living image system. IHC assays were used to detect the levels of EMT-related proteins in COE reversal in vivo.

RESULT

The results showed that the movement distance and average movement speed of gastric cancer cells after COE treatment were significantly lower than those of the control group. Cytoskeleton staining experiments revealed that COE can significantly change the distribution of skeletal proteins in gastric cancer cells. Additionally, COE treatment significantly reduced the expression of Matrix metalloproteinases (MMP-2, MMP-9) and other proteins. Furthermore, COE can significantly accelerate the degradation of CFL1 protein, and both COE treatment and CFL1 deletion can significantly inhibit EMT and metastasis of gastric cancer cells. Lastly, the number of peritoneal metastases of gastric cancer cells was significantly reduced in animals after COE treatment. COE can reverse the levels of EMT-related proteins while reducing the expression levels of CFL1 protein in vivo.

CONCLUSION

COE can significantly inhibit EMT and metastasis of gastric cancer cells in vivo and in vitro. This effect may be achieved by reducing the stability of CFL1 and inhibiting the assembly of actin in gastric cancer cells.

Poria Acid, Triterpenoids Extracted from Poria cocos, Inhibits the Invasion and Metastasis of Gastric Cancer Cells

Background: Poria cocos (P. cocos) is an important medicinal fungus in traditional Chinese medicine. Poria acid (PA), a triterpenoid compound, is an effective component of traditional Chinese medicine P. cocos. This experiment investigated the anti-gastric cancer biological activity of PA in vitro. Methods: The effect of PA on the viability of gastric cancer cells was detected by the thiazolyl blue (MTT) assay. Cell adhesion assays were used to detect changes in the adhesion of cells treated after PA (0, 20, 40, and 80 µmol/L). The ability of cell invasion and migration were detected by Transwell assays and wound healing assays. A high-content imaging system was used to dynamically record the motility of the gastric cancer cells after PA (0, 20, 40, and 80 µmol/L) treatment. Western blotting was used to detect the expression of epithelial–mesenchymal transformation (EMT), invasion and migration related proteins. Results: The MTT assay showed that the proliferation of gastric cancer cells was significantly inhibited after PA treatment. Cell adhesion experiments showed that the adhesion of gastric cancer cells was significantly decreased after PA treatment. Compared with the control group, the wound healing area of the gastric cancer cells treated with different concentrations of PA decreased. The Transwell assay showed that the number of gastric cancer cells passing through the cell membrane were significantly reduced after PA treatment. In addition, after PA treatment, the cells’ movement distance and average movement speed were significantly lower than those of the control group. Finally, PA can significantly alter the expression of EMT-related proteins E-cadherin, N-cadherin, and Vimentin and decreased the expressions of metastasis-related proteins matrix metalloproteinase (MMP) 2, MMP-9 and tissue inhibition of matrix metalloproteinase (TIMP)1 in the gastric cancer cells. Conclusions: Triterpenoids from P. cocos have significant biological activity against gastric cancer, and the mechanism may be involved in the process of epithelial–mesenchymal transformation.

Celastrus Orbiculatus Extract Inhibits the Epithelial-mesenchymal Transition Process by Transforming Growth Factor-β Signaling Pathway in Gastric Cancer

BACKGROUND

Gastric cancer is the fifth most common tumor and has the third-highest mortality rate among various malignant tumors, and the survival rate of patients is low. Celastrus orbiculatus extract (COE) has been shown to inhibit the activity of a variety of tumors. In this study, we examined the inhibition of the epithelial-mesenchymal transition (EMT) process in gastric cancer cells by COE through the transforming growth factor-β(TGF-β) signaling pathway.

METHODS

COE was first diluted to various concentrations and then used to treat SGC-7901, BGC-823, MGC-803, and AGS cells. Cell proliferation was assessed by an MTT (thiazole blue) assay. Transwell assays were used to assess cell invasion and migration. The high-content imaging technology was used to further observe the effects of the drug on cell invasion and migration. Western blotting was used to assess the effects of the drug on the expression of EMT and Smad2/3 signaling pathway-related proteins.

RESULTS

We found that COE inhibited the migration and invasion of AGS gastric cancer cells in a dose-dependent manner. Consequently, COE decreased the expression of EMT-related proteins and proteins related to the Smad2/3 signaling pathway in gastric cancer cells, inhibiting the migration and invasion of gastric cancer cells, and this effect occurred through the TGF-β signaling pathway.

SUMMARY

We investigated that COE could inhibit the proliferation of gastric cancer cells and inhibit invasion and metastasis by inhibiting the EMT process at the molecular level and its effect on the TGF-β signaling pathway.

EGFR testing patterns and detection of EGFR exon 20 insertions among patients with NSCLC in the US

Introduction/Objective

Epidermal growth factor receptor (EGFR) mutations are common in non-small cell lung cancer (NSCLC). EGFR exon 20 insertions (EGFRex20ins), a rare subset of EGFR mutations, are refractory to tyrosine kinase inhibitors. With the development of targeted therapies for EGFRex20ins, such as mobocertinib, molecular testing is required to optimize treatment. A better understanding of real-world EGFR detection patterns is needed to maximize patient outcomes.

Methods/Case Report

This retrospective study describes EGFR testing and EGFRex20ins detection patterns in patients with NSCLC in the United States. The Flatiron Health electronic health record database was used to identify patients ≥18 years, with advanced NSCLC, and with ≥2 clinic visits between 01/01/2011 and 12/31/2020. Baseline demographics, clinical characteristics, EGFR testing, and EGFRex20ins detection rates by sex, race, and smoking history were summarized.

Results (if a Case Study enter NA)

A total of 67,281 patients with NSCLC were identified. EGFR testing increased from 44% in 2011 to 77% in 2020. Of all patients, 44,926 (66.8%) were tested: 50.8% female; 3.3% Asian; 16.0% never-smokers. Of all patients, 22,355 (33.2%) were not tested: 41.4% female; 1.2% Asian; 7.5% never-smokers. Of those tested, 6,245 (13.9%) patients had EGFR mutations: 65.9% female; 11.8% Asian; 48.4% never-smokers.

EGFRex20ins detection rates changed from 0.6% in 2011 to 1.0% in 2019 and 0.7% in 2020. Of those tested, 304 patients had EGFRex20ins: 58.2% female; 8.2% Asian; 50.3% never-smokers. EGFR testing was higher in females (71.2%) than males (62.8%), never-smokers (84.5%) than those with a smoking history (64.6%), and Asian patients (84.2%) than White (66.6%), Black (65.4%), or other patients (69.5%). Of those tested, EGFRex20ins mutations were detected in 0.8% of females (males: 0.6%), 2.2% of never-smokers (with smoking history: 0.4%), and 1.7% of Asians (White: 0.6%, Black: 0.6%, other patients: 0.7%) had EGFRex20ins. A similar trend was observed for EGFR mutations with higher proportions of females, never-smokers, and Asian patients affected.

Conclusion

EGFR testing and EGFRex20ins detection rates have increased. However, not all patient subgroups were tested at the same rate and undertesting occurred in all subgroups. Further education of specialists diagnosing NSCLC is warranted to ensure all patients receive biomarker testing and benefit from emerging EGFRex20ins- targeted therapies.

MACC1 silencing inhibits cell proliferation and induces cell apoptosis of lung adenocarcinoma cells through the β-catenin pathway

It has been documented that over-expression of metastasis-associated in colon cancer-1 (MACC1) is related to poor prognosis in non-small cell lung cancer (NSCLC). This study investigates the function and underlying molecular mechanisms of MACC1 in lung adenocarcinoma. Here, we firstly employed immunohistochemistry, western blotting, real-time PCR, and online database to demonstrate that MACC1 expression was elevated in tumor tissues compared with tumoradjacent or normal tissues. Real-time PCR, CCK-8, colony formation western blotting, Hoechst staining, and flow cytometry assays then evaluated the effects of MACC1 knockdown on the cell cycle, cell proliferation and apoptosis in A549  and H1299 adenocarcinoma cells. Result highlighted that MACC1 knockdown inhibited cell proliferation, induced G0/ G1 phase arrest and promoted cell apoptosis in vitro. Mechanistic analysis revealed it also up-regulated expression levels of bax, cleaved-caspase-3 and cleaved-PARP while down-regulating cyclin D1, c-myc, bcl-2, and β-catenin expression in A549 cells. Intriguingly, up-regulation of β-catenin suppressed G0/G1 phase arrest and apoptosis in MACC1-silenced A549 cells and this was accompanied by increased levels of cyclin D1, c-myc, and bcl-2. Collectively, our results indicate that MACC1 knockdown effectively inhibited cell proliferation and promoted apoptosis of lung adenocarcinoma cells by regulating the β-catenin pathway.

Low Wall Shear Stress Is Associated with Local Aneurysm Wall Enhancement on High-Resolution MR Vessel Wall Imaging

BACKGROUND AND PURPOSE

Some retrospective studies have found that the aneurysm wall enhancement on high-resolution MR vessel wall postgadolinium T1WI has the potential to distinguish unstable aneurysms. This study aimed to identify hemodynamic characteristics that differ between the enhanced and nonenhanced areas of the aneurysm wall on high-resolution MR vessel wall postgadolinium T1WI.

MATERIALS AND METHODS

TOF-MRA and high-resolution MR vessel wall T1WI of 25 patients were fused to localize the enhanced area of the aneurysm wall. Using computational fluid dynamics, we studied the aneurysm models. Mean static pressure, mean wall shear stress, and oscillatory shear index were compared between the enhanced and nonenhanced areas.

RESULTS

The aneurysmal enhanced area had lower wall shear stress (P < .05) and a lower oscillatory shear index (P = .021) than the nonenhanced area. In addition, the whole aneurysm had lower wall shear stress (P < .05) and a higher oscillatory shear index (P = .007) than the parent artery.

CONCLUSIONS

This study suggests that there are hemodynamic differences between the enhanced and nonenhanced areas of the aneurysm wall on high-resolution MR vessel wall postgadolinium T1WI.

Bioinformatics analysis of gene expression profiles in the rat cerebral cortex following traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a serious neurodisorder commonly caused by sports related events or violence. It is the leading cause of disability in people under 40.

AIM

In order to elucidate the molecular mechanism of the secondary injury after TBI.

MATERIALS AND METHODS

In this study, we downloaded gene expression profile on TBI model with sham controls for gene set enrichment analysis and pathway analysis.

RESULTS

At a q-value of 5%, 361 genes were up-regulated and 373 were down-regulated in samples obtained at 48 hours after TBI. Functional analyses revealed that steroid biosynthesis, cell cycle, metal ion transport, inflammation and apoptosis were significantly dysregulated during the late period after trauma. In addition, MAPK3 (mitogen-activated protein kinase 3), was identified as the hub node in the protein-protein interaction (PPI) network constructed by the differentially expressed genes (DEGs).

CONCLUSIONS

Further elucidation of genes and proteins in our study may reveal their potential as novel therapeutic targets.

Clinical activity observed in a phase I dose escalation trial of an oral c-met and ALK inhibitor, PF-02341066

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Background: PF-02341066 (PF) is a selective, ATP-competitive, small molecule oral inhibitor of the c-Met/HGFR and ALK receptor tyrosine kinases that has not previously been tested in humans. A Phase 1 dose-escalation trial evaluating PF as an oral single agent was conducted to investigate safety, PK and PD in patients (pts) with advanced cancer (excluding leukemias). Methods: PF was administered under fasting conditions QD or BID on a continuous schedule to pts in successive dose-escalating cohorts at doses ranging from 50 mg QD to 300 mg BID. Pts with advanced cancer were enrolled in the study. Results: Thirty-seven pts were enrolled into the dose escalation part of the study. Tumor types included colorectal, pancreatic, sarcoma, ALCL and NSCLC. The MTD was 250 mg BID. Three DLTs were observed: grade 3 increase in ALT (1 pt at 200 mg QD) and grade 3 fatigue (2 pts at 300 mg BID). The most common AEs were nausea, emesis, fatigue and diarrhea. Nausea and emesis were independent of dose or duration of treatment. Mean AUC (30–57% CV) and Cmax (36–69% CV) increased proportionally with dose from 100 mg QD to 300 mg BID. The median terminal half-life was 46 hours. A 2- to 4-fold increase in the oral midazolam (MDZ) AUC was observed following 28-days of PF dosing at 100 mg QD (n = 3) and 300 mg BID (n = 2), respectively, suggesting PF to be an inhibitor of CYP3A. Ten pts have entered an enriched RP2D cohort of pts with tumors harboring c-Met amplification/gene mutation or ALK fusion genes. There has been 1 confirmed PR in a sarcoma pt with ALK rearrangement (inflammatory myofibroblastic tumor). Among 10 NSCLC pts whose tumors harbor EML4-ALK rearrangement, 1 pt has had a PR, 2 pts have achieved unconfirmed PR and 4 pts have had SD (3 have experienced reduction in tumor burden by ∼20% in measurable lesions and 1 has been treated for 28 weeks). Conclusions: The MTD of PF is 250 mg BID. The major AEs were fatigue or GI-related, and all AEs were manageable and reversible. There was no evidence of non-linear PK at PF doses >100 QD. Treatment with PF-02341066 resulted in promising clinical activity against tumors carrying activating ALK gene rearrangements. Further study of PF in pts with ALK-dependent tumors is warranted.

[Table: see text]

Proposed staging system modifications for advanced bronchioloalveolar carcinoma supported with a population-based validation study

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Background: Concordant with surgical series, our prior analysis of US SEER data demonstrates improved survival for BAC patients with stage IIIB disease due to multiple lesions in the same lobe compared to other stage IIIB patients, and also for patients with ipsilateral multicentric BAC compared to those with distant metastasis. In order for the BAC staging system to accurately reflect survival for these distinct patient subsets, we propose a revised staging system for advanced BAC and validate this system using California Cancer Registry (CCR) data. Methods: A case-only analysis of incident BAC cases in CCR during 1999–2003 was conducted. Based on modeling from our prior SEER analysis, the T4 descriptor for multiple tumors in the same lobe was downstaged to T3, and the M1 descriptor for ipsilateral multicentric BAC was downstaged to T4. The primary outcome measured was overall survival (OS). OS univariate analyses were conducted using the Kaplan-Meier method; multivariate survival analyses were performed using Cox proportional hazards ratios. Results: 1909 incident cases of histologically-confirmed BAC were analyzed. Using the proposed criteria, 162 (25%) of the 654 advanced BAC cases were reclassified: 73 cases with multiple lesions in the same lobe as T3 (stage II T3N0M0 [n=53] or T3NXM0 [n=1], stage IIIA T3N1–2M0 [n=18], stage IIIB T3N3M0 [n=1]); 89 cases with ipsilateral intrapulmonary metastasis were reclassified as T4 (stage IIIB, T4N1- 3M0). Univariate OS analysis of this validation set reveals an improved fit for the proposed staging system compared to the existing staging system ( Table 1 ). Analysis by stage reveals improvement in this proposed prognostic model over the existing staging system on multivariate survival analysis after adjustment for relevant clinicopathologic variables ( Table ). Conclusions: Our proposed BAC staging system modifications more accurately reflect survival characteristics for this unique type of non-small-cell lung cancer.

[Table: see text]

A novel intermediate endpoint for predicting overall survival in men with metastatic castration-recurrent prostate cancer (CRPC)

5113

Background: In this proposed study, we developed and validated a novel composite clinical benefit endpoint constructed from symptoms that have intrinsic clinical importance in 800 men with CRPC who were treated with front-line chemotherapy. Methods: Data from nine multimember trials (five phase II and four randomized phase III studies) conducted by the Cancer and Leukemia Group B (CALGB) from 1992–2004 were combined. Eligible patients had progressive adenocarcinoma of the prostate during androgen ablation (despite castrate testosterone levels), an ECOG performance status of 0–2, adequate hematologic, renal and hepatic functions. The tripartite composite clinical benefit endpoint (TCCBE) had three components: one based on disease progression (whether it be PSA, bone, or soft tissue progression), and the second based on weight loss (defined as at least 10% decline from baseline) or on performance status (PS) decline (by at least one level) to capture clinical deterioration. The third component was based on pain control and opioid analgesic use (no or yes). For a person to fall in the TCCBE “yes” category, at least two of the three components had to be recorded as no. For instance, if a patient at 3 months had no progression, no change in weight and did not use opioid analgesic, then he will be classified in the “yes” group and for the purpose of this analysis was considered as someone who achieved “clinical benefit”. The sample was randomly split into 526 (67%) and 274 (33%) men in the training and testing datasets, respectively. Results: From the training dataset, the median survival times in men who had and did not have clinical benefit were 20.9 months (95% confidence interval (CI) = 18.5–22.8) and 11.1 months (95% = 8.79–12.6, p- value<0.001). In the testing dataset, the median survival times in men with and without clinical benefit were 21.7 months (95% CI= 19.1–26.1) and 8.8 months (95% CI= 7.8–11.6) and in men. The hazard ratio (HR) for men with a clinical benefit compared to men without was 0.52 (95% CI= 0.43–0.62, P<0.001). Conclusions: The TCCBE is a statistically significant intermediate endpoint for predicting overall survival. Prospective validation of this endpoint is needed.

No significant financial relationships to disclose.

An elevated body mass (BMI) index predicts for better clinical outcomes in men with metastatic hormone refractory prostate cancer (HRPC)

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Background: Previous articles have reported that an elevated BMI was associated with an increased risk of biochemical failure in hormone sensitive patients. We asked the question as to whether an elevated BMI predicts for worst clinical outcomes, namely overall survival (OS) and prostate-cancer survival (PCS), among 1,216 men with HRPC. Methods: Patients were enrolled on eight clinical trials conducted by the Cancer and Leukemia Group B (CALGB). Eligible patients had progressive prostate cancer during androgen deprivation therapy (with documented castrate levels of testosterone), an ECOG performance status of 0–2, adequate hematologic, renal and hepatic function. We used the NIH definition to classify patients as: normal (<25 kg/m2), overweight (25–29 kg/m2 ), mildly obese (30–34 kg/m2), and moderately to severely obese (≥35 kg/m2). PCS was defined as the time from study entry to the time of death due to prostate cancer. The proportional hazards model was used to explore the prognostic significance of BMI in predicting OS and PCS. Results: The median BMI was 27.7 kg/m2 (inter-quartile range = 25.2–31.0 kg/m2 ). Twenty three percent (285/1216) of the patients had normal BMI, 46% (555/1216) were overweight, 23% (280/1216) were mildly obese, and 8% (96/1216) were moderately to severely obese. In multivariate analysis, adjusting for age, race, performance status, hemoglobin, PSA, LDH, alkaline phosphatase, testosterone, years since diagnosis, presence of visceral disease and Gleason scores, BMI was a statistically significant predictor of OS and PCS. Compared to normal men, the hazard ratios (HR) of overweight patients was 0.80 (95% CI = 0.69–0.93, p-value = 0.003), for mildly obese patients was 0.86 (95% CI = 0.72–1.02, p-value = 0.087) and for moderately to severely obese men it was 0.60 (95% CI = 0.47–0.78, p-value < 0.001). In addition, the HRs for PCS for overweight patients was 0.83 (95% CI = 0.70–0.97, p-value = 0.023), was 0.88 (95% CI = 0.72–1.06, p-value = 0.179) for mildly obese and for moderately to severely obese was 0.62 (95% CI = 0.47–0.81, p-value = 0.001) compared to men with normal BMI. Conclusions: Contrary to what was reported, these findings demonstrate an inverse relationship between BMI and clinical outcomes in men with HRPC.

[Table: see text]

Production of a novel FK520 analog in Streptomyces hygroscopicus: improving titer while minimizing impurities

FK520, also called ascomycin, is an immunosuppressive agent produced by Streptomyces hygroscopicus. Engineering the polyketide synthase genes of the parent strain generated novel FK520 analogs with the potential for improved in vivo stability. By replacing the acyl transferase (AT) domain in the polyketide synthase module 8 with an AT specific for methylmalonyl CoA (the rapamycin AT 3), the strain produced 13-desmethoxy-13-methyl-FK520 (13dmmFK520). Process development and scale-up studies of this recombinant S. hygroscopicus strain producing 13dmmFK520 are described here. Production kinetics and compound stability in fermentation broth were significantly different compared to the native FK520. Fermentation of the new strain resulted in the synthesis of a contaminating substance that co-purified with the 13dmmFK520. To optimize 13dmmFK520 production and to facilitate purification, growth parameters and media development were examined. Although a medium was identified that increased product titers by ca. 300%, the ratio of impurity to product was doubled. Lower dissolved oxygen (20% compared to 50% and 80%) increased titers by 20% with no appreciable effect on the concentration of impurity. Increasing the fermentation pH from 6.0 to 6.5 did not change the 13dmmFK520 titer, but reduced the impurity-to-product ratio by approximately 450%.

Modulation of epothilone analog production through media design

Recently, the epothilone polyketide synthase (PKS) was successfully introduced into a heterologous production host for the large-scale production of epothilone D. We have found that at least three other epothilones can also be produced as the major fermentation product of this recombinant strain by supplementation of specific substrates to the production media. Addition of acetate or propionate to the media results in modulation of the epothilone D:C ratio, whereas addition of L-serine with either acetate or propionate yields epothilone H(1) or H(2) as the major product. This strategy permits production of at least four novel epothilones by culturing a single host with a genetically modified epothilone PKS in various media.

New anti-huntingtin monoclonal antibodies: implications for huntingtin conformation and its binding proteins

We produced eight anti-huntingtin (Htt) monoclonal antibodies (mAbs), several of which have novel binding patterns. Peptide array epitope mapping shows that mAbs MW1-6 specifically bind the polyQ domain of Htt exon 1. On Western blots of extracts from mutant Htt knock-in mouse brain and Huntington's disease lymphoblastoma cell lines, MW1-5 all strongly prefer to bind to the expanded polyQ repeat form of Htt, displaying no detectable binding to normal Htt. These results suggest that the polyQ domain can assume different conformations that are distinguishable by mAbs. This idea is supported by immunohistochemistry with wild type (WT) and mutant Htt transgenic mouse (R6) brains. Despite sharing the same epitope and binding preferences on Western blots, MW1-5 display distinct staining patterns. MW1 shows punctate cytoplasmic and neuropil staining, while MW2-5 strongly stain the neuronal Golgi complex. MW6, in contrast, stains neuronal somas and neuropil. In addition, despite their preference for mutant Htt on blots, none of these mAbs show enhanced staining of R6 brains over WT, and show no binding of the Htt-containing nuclear inclusions in R6 brains. This suggests that in its various subcellular locations, the polyQ domain of Htt either takes on different conformations and/or is differentially occluded by Htt binding proteins. In contrast to MW1-6, MW7, and 8 can differentiate transgenic from WT mice by staining nuclear inclusions in R6/2 brain; MW8 displays no detectable staining in WT brain and stains only inclusions in R6/2 brain. Epitope mapping reveals that MW7 and 8 specifically bind the polyP domains and amino acids 83-90, respectively. As with MW1-6, the epitopes for MW7 and 8 are differentially available in the various subcellular compartments where Htt is found.

Enhancing the atom economy of polyketide biosynthetic processes through metabolic engineering

Polyketides, a large family of bioactive natural products, are synthesized from building blocks derived from alpha-carboxylated Coenzyme A thioesters such as malonyl-CoA and (2S)-methylmalonyl-CoA. The productivity of polyketide fermentation processes in natural and heterologous hosts is frequently limited by the availability of these precursors in vivo. We describe a metabolic engineering strategy to enhance both the yield and volumetric productivity of polyketide biosynthesis. The genes matB and matC from Rhizobium trifolii encode a malonyl-CoA synthetase and a putative dicarboxylate transport protein, respectively. These proteins can directly convert exogenous malonate and methylmalonate into their corresponding CoA thioesters with an ATP requirement of 2 mol per mol of acyl-CoA produced. Heterologous expression of matBC in a recombinant strain of Streptomyces coelicolor that produces the macrolactone 6-deoxyerythronolide B results in a 300% enhancement of macrolactone titers. The unusual efficiency of the bioconversion is illustrated by the fact that approximately one-third of the methylmalonate units added to the fermentation medium are converted into macrolactones. The direct conversion of inexpensive feedstocks such as malonate and methylmalonate into polyketides represents the most carbon- and energy-efficient route to these high value natural products and has implications for cost-effective fermentation of numerous commercial and development-stage small molecules.

In vitro study of possible role of dietary fiber in lowering postprandial serum glucose

There have been many reports concerning the role of dietary fiber in lowering postprandial serum glucose, and the main mechanism was regarded as the viscosity of different dietary fibers in hampering diffusion of glucose and postponing absorption and digestion of carbohydrates. In this paper, two kinds of water-insoluble dietary fibers, water-insoluble dietary fiber of wheat bran and enzyme-resistant starch of maize amylose, and four kinds of water-soluble dietary fibers, water-soluble dietary fiber of wheat bran, carboxymethyl cellulose, guar gum, and xanthan gum, were used to investigate their postprandial serum glucose lowering mechanism in vitro. The results showed that these dietary fibers lowered postprandial serum glucose levels at least by three mechanisms. First, dietary fibers increase the viscosity of small intestine juice and hinder diffusion of glucose; second, they bind glucose and decrease the concentration of available glucose in the small intestine; and, third, they retard alpha-amylase action through capsuling starch and the enzyme and might directly inhibit the enzyme. All of these decreased the absorption rate of glucose and the concentration of postprandial serum glucose.

A geminivirus replication protein interacts with the retinoblastoma protein through a novel domain to determine symptoms and tissue specificity of infection in plants

Geminiviruses replicate in nuclei of mature plant cells after inducing the accumulation of host DNA replication machinery. Earlier studies showed that the viral replication factor, AL1, is sufficient for host induction and interacts with the cell cycle regulator, retinoblastoma (pRb). Unlike other DNA virus proteins, AL1 does not contain the pRb binding consensus, LXCXE, and interacts with plant pRb homo logues (pRBR) through a novel amino acid sequence. We mapped the pRBR binding domain of AL1 between amino acids 101 and 180 and identified two mutants that are differentially impacted for AL1-pRBR interactions. Plants infected with the E-N140 mutant, which is wild-type for pRBR binding, developed wild-type symptoms and accumulated viral DNA and AL1 protein in epidermal, mesophyll and vascular cells of mature leaves. Plants inoculated with the KEE146 mutant, which retains 16% pRBR binding activity, only developed chlorosis along the veins, and viral DNA, AL1 protein and the host DNA synthesis factor, proliferating cell nuclear antigen, were localized to vascular tissue. These results established the importance of AL1-pRBR interactions during geminivirus infection of plants.

Precursor-directed biosynthesis of 6-deoxyerythronolide B analogs in Streptomyces coelicolor: understanding precursor effects

A fermentation process employing precursor-directed biosynthesis is being developed for the manufacture of 6-deoxyerythronolide B (6-dEB) analogues. Through a plasmid-based system in Streptomyces coelicolor, 6-dEB synthesis is catalyzed by 6-dEB synthase (DEBS). 6-dEB synthesis is abolished by inactivation of the ketosynthase (KS) 1 domain of DEBS but can be restored by providing synthetic activated diketides. Because of its inherent catalytic flexibility, the KS1-deficient DEBS is capable of utilizing unnatural diketides to form various 13-substituted 6-dEBs. Here we characterize process variables associated with diketide feeding in shake-flask experiments. 13-R-6-dEB production was found to depend strongly on diketide feed concentrations, on the growth phase of cultures at feeding time, and on the R-group present in the diketide moiety. In all cases a major portion of the fed diketides was degraded by the cells.

Chlorpromazine at comparatively low concentrations potentiates carbachol-induced tonic contraction of ileal longitudinal smooth muscle of the guinea-pig

The neuroleptic phenothiazine derivative chlorpromazine (CPZ) at high concentration (1 x 10(-5) M) decreased either the phasic or tonic contraction in response to carbachol and the carbachol-induced increase in [Ca2+]i in both phases in ileal muscle. In contrast, CPZ at low concentrations (8 x 10(-7) - 5 x 10(-6) M) decreased only the phasic contraction and potentiated the tonic contraction induced by carbachol. However, CPZ at these concentrations dose-dependently decreased the carbachol-induced increase in [Ca2+]i in both phases. These results suggested that CPZ dose-dependently decreased the initial phasic contraction in response to carbachol by inhibition of Ca2+ release from the intracellular storage sites. CPZ at low concentrations appears to increase Ca2+ sensitivity to contractile proteins in the carbachol-induced tonic phase. CPZ dose-dependently reduced the 60 mM K(+)-induced phasic and tonic responses and a concomitant decrease in [Ca2+]i in ileal muscle.