Antimony Redox Catalysis: Hydroboration of Disulfides through Unique Sb(I)/Sb(III) Redox Cycling.

The stibinidene ArSbI (Ar = [2,6-(tBuN═CH)2-C6H3], 1) reacts with S2Tol2 (Tol = p-tolyl) to form ArSbIII(STol)2 (2), which upon treatment with pinacolborane, regenerates 1. These processes unveil an unprecedented antimony redox catalysis involving Sb(I)/Sb(III) cycling for the hydroboration of organic disulfides. Elementary reaction studies and density functional theory calculations support that the catalysis mimics transition metal processes, proceeding through oxidative addition, ligand metathesis, and reductive elimination. The thiophenols and sulfidoborates generated from the hydroboration of disulfides react in situ with α,ß-unsaturated carbonyl compounds with the assistance of 1 as a base catalyst. These tandem reactions establish a one-pot synthetic method for ß-sulfido carbonyl compounds, in which a stibinidene functions as a redox catalyst and a base catalyst successively, illustrating the versatility and efficiency of antimony catalysis in organic synthesis.

Acellular embryoid body and hydroxybutyl chitosan composite hydrogels promote M2 macrophage polarization and accelerate diabetic cutaneous wound healing.

Diabetic wound healing is delayed due to persistent inflammation, and macrophage-immunomodulating biomaterials can control the inflammatory phase and shorten the healing time. In this study, acellular embryoid bodies (aEBs) were prepared and mixed with thermosensitive hydroxybutyl chitosan (HBC) hydrogels to produce aEB/HBC composite hydrogels. The aEB/HBC composite hydrogels exhibited reversible temperature-sensitive phase transition behavior and a hybrid porous network. In vitro analysis showed that the aEB/HBC composite hydrogels exhibited better antimicrobial activity than the PBS control, aEBs or HBC hydrogels and promoted M0 to M2 polarization but not M1 to M2 macrophage repolarization in culture. The in vivo results showed that the aEB/HBC composite hydrogels accelerated cutaneous wound closure, re-epithelialization, ingrowth of new blood vessels, and collagen deposition and reduced the scar width during wound healing in diabetic mice over time. Macrophage phenotype analysis showed that the aEB/HBC composite hydrogels induce M2 macrophage reactions continually, upregulate M2-related mRNA and protein expression and downregulate M1-related mRNA and protein expression. Therefore, the aEB/HBC composite hydrogels have excellent antimicrobial activity, promote M2 macrophage polarization and accelerate the functional and structural healing of diabetic cutaneous wounds.

Aromatic Acids and Leucine Derivatives Produced from the Deep-Sea Actinomycetes Streptomyceschumphonensis SCSIO15079 with Antihyperlipidemic Activities.

Six new aromatic acids (1-6) and three new leucine derivatives containing an unusual oxime moiety (7-9) were isolated and identified from the deep-sea-derived actinomycetes strain Streptomyces chumphonensis SCSIO15079, together with two known compounds (10-11). The structures of 1-9 including absolute configurations were determined by detailed NMR, MS, and experimental and calculated electronic circular dichroism spectroscopic analyses. Compounds 1-9 were evaluated for their antimicrobial and cytotoxicity activities, as well as their effects on intracellular lipid accumulation in HepG2 cells. Compounds 3 and 4, with the most potent inhibitory activity on intracellular lipid accumulation at 10 µM, were revealed with potential antihyperlipidemic effects, although the mechanism needs to be further studied.

Natural products from mangrove sediments-derived microbes: Structural diversity, bioactivities, biosynthesis, and total synthesis.

The mangrove forests are a complex ecosystem, and the microbial communities in mangrove sediments play a critical role in the biogeochemical cycles of mangrove ecosystems. Mangrove sediments-derived microbes (MSM), as a rich reservoir of natural product diversity, could be utilized in the exploration of new antibiotics or drugs. To understand the structural diversity and bioactivities of the metabolites of MSM, this review for the first time provides a comprehensive overview of 519 natural products isolated from MSM with their bioactivities, up to 2021. Most of the structural types of these compounds are alkaloids, lactones, xanthones, quinones, terpenoids, and steroids. Among them, 210 compounds are obtained from bacteria, most of which are from Streptomyces, while 309 compounds are from fungus, especially genus Aspergillus and Penicillium. The pharmacological mechanisms of some representative lead compounds are well studied, revealing that they have important medicinal potentials, such as piericidins with anti-renal cell cancer effects, azalomycins with anti-MRSA activities, and ophiobolins as antineoplastic agents. The biosynthetic pathways of representative natural products from MSM have also been summarized, especially ikarugamycin, piericidins, divergolides, and azalomycins. In addition, the total synthetic strategies of representative secondary metabolites from MSM are also reviewed, such as piericidin A and borrelidin. This review provides an important reference for the research status of natural products isolated from MSM and the lead compounds worthy of further development, and reveals that MSM have important medicinal values and are worthy of further development.

Bisabolanoic acid A, a new polychiral sesquiterpene with AChE inhibitory activity from a mangrove-derived fungus Colletotrichum sp.

A new polychiral bisabolane sesquiterpene, bisabolanoic acid A (1), was isolated from the mangrove-derived fungus Colletotrichum sp. SCSIO KcB3-2. Its planar structure was identified on the basis of spectroscopic data analysis (HRESIMS, 1D, and 2D NMR), and the absolute configurations of three chiral carbons were determined by experimental and calculated electronic circular dichroism (ECD) and optical rotatory dispersion (ORD), together with Mo2(OAc)4-induced ECD methods. Bisabolanoic acid A (1) showed moderate inhibitory activity against acetylcholinesterase (AChE) with IC50 value of 2.2 µM, and the in silico molecular docking was also performed.

Metastatic Pattern Discriminates Survival Benefit of Type of Surgery in Patients With De Novo Stage IV Breast Cancer Based on SEER Database.

Background: The role of surgery and surgery type in de novo stage IV breast cancer (BC) is unclear. Methods: We carried out a retrospective cohort study that included the data of 4,108 individuals with de novo stage IV BC abstracted from SEER (Surveillance, Epidemiology, and End Results) data resource from 2010 to 2015. The patients were stratified into the non-surgery group, breast-conserving (BCS) surgery group, and mastectomy group. Inverse probability propensity score weighting (IPTW) was then used to balance clinicopathologic factors. Overall survival (OS), as well as the breast cancer-specific survival (BCSS), was assessed in the three groups using Kaplan-Meier analysis and COX model. Subgroups were stratified by metastatic sites for analysis. Results: Of the 4,108 patients, 48.5% received surgery and were stratified into the BCS group (574 cases) and mastectomy group (1,419 cases). After IPTW balance demographic and clinicopathologic factors, BCS and mastectomy groups had better OS (BCS group: HR, 0.61; 95% CI: 0.49-0.75; mastectomy group: HR, 0.7; 95% CI: 0.63-0.79) and BCSS (BCS group: HR, 0.6; 95% CI, 0.47-0.75; mastectomy group: HR, 0.71; 95% CI, 0.63-0.81) than the non-therapy group. Subgroup analyses revealed that BCS, rather than mastectomy, was linked to better OS (HR, 0.66; 95% CI: 0.48-0.91) and BCSS (HR, 0.63; 95% CI: 0.45-0.89) for patients with bone-only metastasis. For patients with viscera metastasis or bone+viscera metastases, BCS achieved similar OS (viscera metastasis: HR, 1.05; 95% CI: 0.74-1.48; bone+viscera metastases: HR, 1.01; 95% CI: 0.64-1.61) and BCSS (viscera metastasis: HR, 0.94; 95% CI: 0.64-1.38; bone+viscera metastases: HR, 1.06; 95% CI: 0.66-1.73) in contrast with mastectomy. Conclusions: Local surgery for patients with distant metastasis (DS) exhibited a remarkable survival advantage in contrast with non-operative management. BCS may have more survival benefits for patients with de novo stage IV BC with bone-only metastasis than other metastatic sites. Decisions on de novo stage IV BC primary surgery should be tailored to the metastatic pattern.

Research on the cutoff tumor size of omitting radiotherapy for BCSS after breast conserving surgery in women aged 65 years or oder with low-risk invasive breast carcinoma: Results based on the SEER database.

BACKGROUND: Radiotherapy after breast-conserving surgery (BCS) is not always necessary in older women staged T1N0M0 with low-risk invasive breast cancer, but few studies have concluded the detailed tumor size as a reference for avoiding radiotherapy. The study was conducted to explore and identify the optimal cutoff tumor size. METHODS: The study population was from the Surveillance, Epidemiology, and End Results (SEER) database in 2010-2016. Propensity score matching was used to balance the confounders between groups. Predictors associated with survival were analyzed by Kaplan-Meier, X-tile, Cox proportional hazards model and competing risk model. RESULTS: A total of 52049 women and 3846 deaths were included in the cohort with a median follow-up of 34 months. Based on the cutoff value determined by X-tile analysis, the study population were divided into small tumor group (≤14 mm in diameter) and large tumor group (>14 mm in diameter). Small tumors and radiotherapy were correlated with better breast cancer-specific survival (BCSS). In subgroup analysis, the absolute benefit of BCSS in 6 years attributed to radiotherapy was only 0.90% (RT vs. non- RT:98.77% vs. 97.87%) for patients with small tumors but up to 3.33% (RT vs. non- RT:97.10% vs. 93.77%) for those with large tumors. CONCLUSION: Small tumors and adjuvant radiotherapy were associated with improved long-term prognosis, and 14 mm in diameter was the cutoff tumor size of omitting radiotherapy for patients aged 65 or older with T1N0M0 stage, ER+ and HER2-breast carcinoma after BCS.

Cytotoxic Minor Piericidin Derivatives from the Actinomycete Strain Streptomyces psammoticus SCSIO NS126.

The mangrove-sediment-derived actinomycete strain Streptomyces psammoticus SCSIO NS126 was found to have productive piericidin metabolites featuring anti-renal cell carcinoma activities. In this study, in order to explore more diverse piericidin derivatives, and therefore to discover superior anti-tumor lead compounds, the NS126 strain was further fermented at a 300-L scale under optimized fermentation conditions. As a result, eight new minor piericidin derivatives (piericidins L-R (1-7) and 11-demethyl-glucopiericidin A (8)) were obtained, along with glucopiericidin B (9). The new structures including absolute configurations were determined by spectroscopic methods coupled with experimental and calculated electronic circular dichroism. We also proposed plausible biosynthetic pathways for these unusual post-modified piericidins. Compounds 1 and 6 showed selective cytotoxic activities against OS-RC-2 cells, and 2-5 exhibited potent cytotoxicity against HL-60 cells, with IC50 values lower than 0.1 µM. The new piericidin glycoside 8 was cytotoxic against ACHN, HL-60 and K562, with IC50 values of 2.3, 1.3 and 5.5 µM, respectively. The ability to arrest the cell cycle and cell apoptosis effects induced by 1 and 6 in OS-RC-2 cells, 2 in HL-60 cells, and 8 in ACHN cells were then further investigated. This study enriched the structural diversity of piericidin derivatives and confirmed that piericidins deserve further investigations as promising anti-tumor agents.

LXR-Mediated Regulation of Marine-Derived Piericidins Aggravates High-Cholesterol Diet-Induced Cholesterol Metabolism Disorder in Mice.

Reported as two antirenal cell carcinoma (RCC) drug candidates, marine-derived compounds piericidin A (PA) and glucopiericidin A (GPA) exhibit hepatotoxicity in renal carcinoma xenograft mice. Proteomics and transcriptomics reveal the hepatotoxicity related with cholesterol disposition since RCC is characterized by cholesterol accumulation. PA/GPA aggravate hepatotoxicity in high-cholesterol diet (HCD)-fed mice while exhibiting no toxicity in chow diet-fed mice. High cholesterol accumulation in liver is liver X receptor (LXR)-mediated cytochrome P450 family 7 subfamily a member 1 (CYP7A1) depression and low-density lipoprotein receptor (LDLR) activation. The farnesoid X nuclear receptor (FXR) is also depressed with a downregulated target gene OSTα. Different from PA directly combined with LXRα as an inhibitor, GPA exists as a prodrug in the liver and exerts toxic effects due to transformation into PA. Surface plasmon resonance (SPR) and docking results of 17 piericidins illustrate that glycosides exert no LXRα binding activity. A longer survival time of GPA-treated mice indicates that further exploration in anti-RCC drug research should focus on reducing glycosides transformed into PA and concentrating in the kidney tumor rather than the liver for lowering the risk of hepatotoxicity.

Nomogram Predicts the Role of Contralateral Prophylactic Mastectomy in Male Patients With Unilateral Breast Cancer Based on SEER Database: A Competing Risk Analysis.

BACKGROUND: Contralateral prophylactic mastectomy (CPM) in female breast cancer (FBC) is supported by multiple clinical studies and consensus guidelines, but knowledge of preventive contralateral mastectomy in male breast cancer (MaBC) is very limited and its benefits are still controversial. METHODS: A retrospective cohort study was enrolled with 4,405 MaBC patients who underwent unilateral mastectomy (UM) or CPM from the Surveillance, Epidemiology, and End Results (SEER) database from 1998 to 2015. A nomogram was built based on the corresponding parameters by competing risks regression to predict the 3-year, 5-year, and 8-year probabilities of BCSD (breast cancer-specific death). C-index and calibration curves were chosen for validation. Net reclassification index (NRI) and integrated discrimination improvement (IDI) were used to estimate the nomogram's clinical utility. RESULTS: A total of 4,197 patients received UM and 208 patients received CPM, with 63-months median follow-up. In the competing risks regression, six variables (surgery, marital status, T-stage, N-stage, histology, tumor grade) were significantly associated with BCSD. Based on these independent prognosis factors, a nomogram model was constructed. The C-index 0.75 (95%CI: 0.73-0.77) in the training cohort and 0.73 (95%CI: 0.71-0.74) in the internal validation group suggested robustness of the model. In addition, the calibration curves exhibited favorably. The NRI values (training cohort: 0.54 for 3-year, 0.55 for 5-year, and 0.49 for 8-year BCSD prediction; validation cohort: 0.51 for 3-year, 0.45 for 5-year, and 0.33 for 8-year BCSD prediction) and IDI values (training cohort: 0.02 for 3-year, 0.03 for 5-year, and 0.04 for 8-year BCSD prediction; validation cohort: 0.02 for 3-year, 0.04 for 5-year, and 0.04 for 8-year BCSD prediction) indicated that the model performed better than the AJCC criteria-based tumor staging alone. CONCLUSIONS: The administration of CPM was associated with the decrease in risk of BCSD in patients with MaBC. The nomogram could provide a precise and personalized prediction of the cumulative risk in patients with MaBC after CPM.

Antioxidant CPA-type indole alkaloids produced from the deep-sea derived fungus Aspergillus sp. SCSIO 41024.

Twelve indole alkaloids, including α-cyclopiazonic acid (CPA) (1), nine 2-oxo indole CPA derivatives (2-10), and two open-ring indole CPA derivatives (11 and 12), were isolated from the fermentation broth of a deep-sea derived fungus Aspergillus sp. SCSIO 41024. Their structures and absolute configurations were elucidated mainly by using extensive NMR spectroscopic, mass spectrometric and single crystal X-ray diffraction analysis. To the best of our knowledge, the crystallographic data of 3 and 7 were firstly reported, and the absolute configuration of 3 was confirmed for the first time by the single crystal X-ray diffraction analysis. Most isolated compounds were tested for their antimicrobial, antitumor and radical scavenging activities. In addition, compounds 1, 2 and 11 showed moderate antioxidative activity against DPPH with IC50 values of 190.1, 31.9, 228.4 µg/mL, respectively.

Sesquiterpenoids and meroterpenoids from a mangrove derived fungus Diaporthe sp. SCSIO 41011.

One new sesquiterpenoid, 1-methoxypestabacillin B (1), along with one known sesquiterpenoid (2) and six known chrodrimanin-type meroterpenoids (3‒8) were obtained from the solid cultures of a mangrove endophytic fungus Diaporthe sp. SCSIO 41011. Their structures including the absolute configuration at C-6 of compound 1, were determined by extensive spectroscopic analyses and ECD calculations. Meanwhile, the X-ray crystal structures and absolute configurations of two previously reported chrodrimanins E (3) and H (6), are described for the first time. All the compounds were examined for HIV latency-reversal and anti-influenza A virus activities.

An integrative pan-cancer analysis of COPB1 based on data mining.

BACKGROUND: Cancer will become the leading cause of death worldwide in the 21st century, meanwhile, immunotherapy is the most popular cancer treatment method in recent years. COPI Coat Complex Subunit Beta 1 (COPB1) relates to human innate immunity. However, the role of COPB1 in pan-cancer remains unclear. OBJECTIVE: The purpose of this study was to explore the relationship between COPB1 mRNA expression and tumor infiltrating lymphocytes and immune examination sites in pan-cancer. METHODS: Data from multiple online databases were collected. The BioGPS, UALCAN Database, COSMIC, cBioPortal, Cancer Regulome tools, Kaplan-Meier Plotter and TIMER website were utilized to perform the analysis. RESULTS: Upregulation of COPB1 has been widely observed in tumor tissues compared with normal tissues. Although COPB1 has poor prognosis in pan-cancer, COPB1 high expression was beneficial to the survival of ESCA patients. Unlike ESCA, COPB1 expression in STAD was positively correlated with tumor infiltrating lymphocytes, including B cells, CD8+ T cells, neutrophils, macrophages, and dendritic cells. Finally, we also found that the expression of COPB1 in STAD was positively correlated with PD-L1 and CTLA4. CONCLUSIONS: COPB1 may be a prognostic biomarker for pan-carcinoma, and also provide an immune anti-tumor strategy for STAD based on the expression of COPB1.

Lipopeptide Epimers and a Phthalide Glycerol Ether with AChE Inhibitory Activities from the Marine-Derived Fungus Cochliobolus Lunatus SCSIO41401.

A pair of novel lipopeptide epimers, sinulariapeptides A (1) and B (2), and a new phthalide glycerol ether (3) were isolated from the marine algal-associated fungus Cochliobolus lunatus SCSIO41401, together with three known chromanone derivates (4-6). The structures of the new compounds, including the absolute configurations, were determined by comprehensive spectroscopic methods, experimental and calculated electronic circular dichroism (ECD), and Mo2 (OAc)4-induced ECD methods. The new compounds 1-3 showed moderate inhibitory activity against acetylcholinesterase (AChE), with IC50 values of 1.3-2.5 µM, and an in silico molecular docking study was also performed.

A Competing Risk Analysis Model to Determine the Prognostic Value of Isolated Tumor Cells in Axillary Lymph Nodes for T1N0M0 Breast Cancer Patients Based on the Surveillance, Epidemiology, and End Results Database.

INTRODUCTION: Knowledge of the association between isolated tumor cells (ITCs) in breast cancer patients and the outcome is very limited. We aimed to determine the prognostic value of axillary lymph node ITCs for T1N0M0 female breast cancer (FBC) patients. METHODS: Data for T1N0M0 FBC patients staged ITCs negative [pN0(i-)] and positive [pN0(i+)] were extracted from the Surveillance, Epidemiology, and End Results database from 2004 to 2015. Prognostic predictors were identified by Kaplan-Meier analysis, competing risk model, and Fine-Gray multivariable regression model. RESULTS: A total of 94,599 subjects were included, 88,632 of whom were staged at pN0(i-) and 5,967 were pN0(i+). Patients staged pN0(i+) had worse breast cancer-specific survival (BCSS) [hazard ratio (HR): 1.298, 95% CI = 1.069-1.576, P = 0.003] and higher breast cancer-specific death (BCSD) rate (Gray's test, P = 0.002) than pN0(i-) group. In the Fine-Gray multivariable regression analysis, the pN0(i+) group had higher BCSD rate (HR: 1.321, 95% CI = 1.109-1.575, P = 0.002) than pN0(i-) group. In subgroup analyses, no significant difference in BCSD was shown between the chemotherapy and non-chemotherapy subgroup (Gray's test, P = 0.069) or radiotherapy and non-radiotherapy subgroup (Gray's test, P = 0.096). CONCLUSION: ITC was independently related to the increase of the BCSD rate and could be identified as a reliable survival predictor for T1N0M0 FBC patients.

Ene-yne Hydroquinones from a Marine-derived Strain of the Fungus Pestalotiopsis neglecta with Effects on Liver X Receptor Alpha.

Seven unusual new ene-yne hydroquinones (1-3, 5-8), including three rare glycosylated derivatives named pestalotioquinosides A-C (6-8), were obtained from the marine-derived strain SCSIO41403 of the fungus Pestalotiopsis neglecta. Their structures including absolute configurations were elucidated by spectroscopic analysis and induced electronic circular dichroism experiments. In silico molecular docking and in vitro surface plasmon resonance studies showed that pestalotioquinoside C (8) could act as a liver X receptor alpha (LXRα) modulator. Further study showed that LXR target gene ABCA1 was significantly upregulated by 8, which revealed 8 as a potential LXRα agonist.

Research on the Role of Combined Chemotherapy and Radiotherapy in Patients With N+ Non-Metastatic Metaplastic Breast Carcinoma: A Competing Risk Analysis Model Based on the SEER database, 2000 to 2015.

PURPOSE: Due to the rarity of metaplastic breast carcinoma (MpBC), no randomized trials have investigated the role of combined chemotherapy and radiotherapy (CCRP) in this condition. We aimed to explore and identify the effectiveness of CCRP in patients with regional lymph node metastasis (N+) non-metastatic MpBC. MATERIALS AND METHODS: Data were obtained from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program database. We assessed the effects of CCRP on overall survival (OS), breast cancer-specific survival (BCSS), and breast cancer-specific death (BCSD) using Kaplan-Meier analysis, competing risk model analysis, and competing risk regression mode analysis. RESULTS: A total of 707 women and 361 death cases were included in the unmatched cohort, of which 76.45% (276/361) were BCSD, and 23.55% (85/361) were non-breast cancer-specific deaths (non-BCSD). Both the ChemT and CCRP groups had better OS (ChemT group: HR: 0.59, 95% CI: 0.45-0.78, P<0.001; CCRP group: HR: 0.31, 95% CI: 0.23-0.41, P<0.001) and BCSS (ChemT group: HR: 0.63, 95% CI: 0.45-0.87, P<0.001; CCRP group: HR: 0.32, 95%CI: 0.22-0.46, P<0.001) than the non-therapy group. Subjects in the CCRP group tended to have significantly lower cumulative BCSD (Gray's test, P=0.001) and non-BCSD (Gray's test, P<0.001) than the non-therapy group or ChemT group. In competing risk regression model analysis, subjects in the CCRP group had a better prognosis in BCSD (HR: 0.710, 95% CI: 0.508-0.993, P=0.045) rather than the ChemT group (HR: 1.081, 95% CI: 0.761-1.535, P=0.660) than the non-therapy group. CONCLUSION: Our study demonstrated that CCRP could significantly decrease the risk of death for both BCSD and non-BCSD and provided a valid therapeutic strategy for patients with N+ non-metastatic MpBC.

Sorbicillfurans A and B, two novel sorbicillinoid adducts from the fungus Penicillium citrinum SCSIO41402.

Two novel sorbicillinoid adducts containing bicyclo[2.2.2]octane and tetrahydrofuran moieties, named sorbicillfurans A and B (1 and 2), were isolated from the static culture of the marine-derived fungus Penicillium citrinum SCSIO41402. Their structures including absolute configurations were determined by spectroscopic and calculated ECD analyses. Sorbicillfurans A and B (1 and 2) are the first examples of sorbicillinoids possessing a tetrahydrofuran unit. In the proposed biosynthetic pathway, sorbicillfuran B (2), harboring a rare and complex polycyclic framework, is probably formed by two Diels-Alder reactions. Both isolates were evaluated for the cytotoxicity against six human cancer cell lines, only sorbicillfuran B (2) showed weak cytotoxicity against HL-60 cells with an IC50 value of 9.6 µM.

Exploring the Natural Piericidins as Anti-Renal Cell Carcinoma Agents Targeting Peroxiredoxin 1.

Anti-renal cell carcinoma (RCC) agents with new mechanisms of action are urgently needed. Twenty-seven natural products of the piericidin class, including 17 new ones, are obtained from a marine-derived Streptomyces strain, and several of them show strong inhibitory activities against ACHN renal carcinoma cells. By exploring the mechanisms of two representative natural piericidin compounds, piericidin A (PA) and glucopiericidin A (GPA), peroxiredoxin 1 (PRDX1) is detected as a potential target by transcriptome data of PA-treated ACHN cells, as well as the paired RCC tumor versus adjacent nontumor tissues. PA and GPA induce cell apoptosis through reducing the reactive oxygen species level caused by upregulated PRDX1 mRNA and protein level subsequently and exhibit potent antitumor efficacy in nude mice bearing ACHN xenografts, with increasing PRDX1 expression in tumor. The interaction between PA/GPA and PRDX1 was supported by the docking analysis and surface plasmon resonance. Moreover, the translocation of PRDX1 into the nucleus forced by PA/GPA is proposed to be a key factor for the anti-RCC procedure. Piericidins provide a novel scaffold for further development of potent anti-RCC agents, and the new action mechanism of these agents targeting PRDX1 may improve upon the limitations of existing targeted drugs for the treatment of renal cancer.

Iakyricidins A-D, Antiproliferative Piericidin Analogues Bearing a Carbonyl Group or Cyclic Skeleton from Streptomyces iakyrus SCSIO NS104.

Iakyricidins A-D (1-4), a carbonyl-containing piericidin derivative and three novel piericidin analogues bearing cyclic skeletons, were isolated from the mangrove sediment derived strain Streptomyces iakyrus SCSIO NS104. These structures were established by spectroscopic techniques, Mosher's method, and ECD calculations. Compounds 2-4 represent a novel skeleton of piericidins with branched chain C-C cyclization, and their biosynthetic pathways are proposed. Compound 1, the first natural carbonyl-containing piericidin derivate, exhibited potent antiproliferative activity against ACHN with an IC50 value of 20 nM.