Triple-negative breast cancer(TNBC)represents an aggressive breast cancer subtype with poor prognosis and limited targeted treatment options.This investigation examined the anticancer potential of Caerulomycin A(Cae A...Triple-negative breast cancer(TNBC)represents an aggressive breast cancer subtype with poor prognosis and limited targeted treatment options.This investigation examined the anticancer potential of Caerulomycin A(Cae A),a natural compound derived from marine actinomycetes,against TNBC.Cae A demonstrated selective inhibition of viability and proliferation in TNBC cell lines,including 4T1,MDA-MB-231,and MDA-MB-468,through apoptosis induction.Mechanistic analyses revealed that the compound induced sustained endoplasmic reticulum(ER)stress and subsequent upregulation of C/EBP homologous protein(CHOP)expression,resulting in mitochondrial damage-mediated apoptosis.Inhibition of ER stress or CHOP expression knockdown reversed mitochondrial damage and apoptosis,highlighting the essential role of ER stress and CHOP in Cae A's anti-tumor mechanism.Both oxygen consumption rate(OCR)and extracellular acidification rate(ECAR)decreased in TNBC cells following Cae A treatment,indicating reduced mitochondrial respiratory and glycolytic capacities.This diminished energy metabolism potentially triggers ER stress and subsequent apoptosis.Furthermore,Cae A exhibited significant anti-tumor effects in the 4T1 tumor model in vivo without apparent toxicity.The compound also effectively inhibited human TNBC organoid growth.These results indicate that Cae A may serve as a potential therapeutic agent for TNBC,with its efficacy likely mediated through the disruption of glucose metabolism and the induction of ER stress-associated apoptosis.展开更多
Actinomycetes have been prolific sources of novel secondary metabolites with a range of biological activities that may ultimately find application as therapeutic compounds. Hence several drug discovery companies are e...Actinomycetes have been prolific sources of novel secondary metabolites with a range of biological activities that may ultimately find application as therapeutic compounds. Hence several drug discovery companies are engaged in isolation of novel bioactive metabolites from these microbial sources. Antibiotics form the major class of such bioactive metabolites and have been widely used for treating infectious diseases. One of the most critical problems in clinical practice is the increase of prevalence of drug resistant strains, especially azole resistance among fungi. Due to this, there is a constant need for development of new antifungal antibiotics having novel scaffolds and/or mechanism of action. In our in-house screening program in the quest of novel and superior antifungal compounds, an actinomycetes strain PM0525875 was isolated from a marine invertebrate. The extracts of this microbe showed potent in-vitro antifungal activity against drug resistant fungal strains. The antifungal active peak from the extract obtained by shake flask fermentation was identified by chromatographic and other analytical techniques during bioactivity guided isolation. Later the fermentation conditions were optimized in 30 L fermentor for the production of sufficient amount antifungal compound for complete structural characterization. Consequently the fermented broth extract was subjected to bioactivity-guided fractionation, to isolate the active principle using different preparative chromatographic techniques followed by its characterization. The active principle was characterized to be Caerulomycin A. Minimum inhibitory concentration (MIC) of the compound was found in the range of 0.39 - 1.56 μg/ml against pathogenic fungal test strains. The phylogenetic analysis of producer strain using 16S rRNA sequence showed closest match with Actinoalloateichus cyanogriseus. Herewith we report the isolation of Caerulomycin A from marine invertebrate-associated Actinoalloteichus sp. using optimized medium and fermentation conditions.展开更多
2,20-Bipyridine(2,20-BiPy)is an attractive core structure present in a number of biologically active natural products,including the structurally related antibiotics caerulomycins(CAEs)and collismycins(COLs).Their bios...2,20-Bipyridine(2,20-BiPy)is an attractive core structure present in a number of biologically active natural products,including the structurally related antibiotics caerulomycins(CAEs)and collismycins(COLs).Their biosynthetic pathways share a similar key 2,20-BiPy-L-leucine intermediate,which is desulfurated or sulfurated at C5,arises from a polyketide synthase/nonribosomal peptide synthetase hybrid assembly line.Focusing on the common off-line modification steps,we here report that the removal of the“auxiliary”L-leucine residue relies on the metallo-dependent amidohydrolase activity of CaeD or ColD.This activity leads to the production of similar 2,20-BiPy carboxylate products that then receive an oxime functionality that is characteristic for both CAEs and COLs.Unlike many metallo-dependent amidohydrolase superfamily proteins that have been previously reported,these proteins(particularly CaeD)exhibited a strong zinc ion-binding capacity that was proven by site-specific mutagenesis studies to be essential to proteolytic activity.The kinetics of the conversions that respectively involve CaeD and ColD were analyzed,showing the differences in the efficiency and substrate specificity of these two proteins.These findings would generate interest in the metallo-dependent amidohydrolase superfamily proteins that are involved in the biosynthesis of bioactive natural products.展开更多
基金supported by the Science and Education Integration Project by the Innovation and Entrepreneurship Office of Nanjing University(No.0214-1480608207)Jiangsu Provincial Research Hospital(No.YJXYY202204)。
文摘Triple-negative breast cancer(TNBC)represents an aggressive breast cancer subtype with poor prognosis and limited targeted treatment options.This investigation examined the anticancer potential of Caerulomycin A(Cae A),a natural compound derived from marine actinomycetes,against TNBC.Cae A demonstrated selective inhibition of viability and proliferation in TNBC cell lines,including 4T1,MDA-MB-231,and MDA-MB-468,through apoptosis induction.Mechanistic analyses revealed that the compound induced sustained endoplasmic reticulum(ER)stress and subsequent upregulation of C/EBP homologous protein(CHOP)expression,resulting in mitochondrial damage-mediated apoptosis.Inhibition of ER stress or CHOP expression knockdown reversed mitochondrial damage and apoptosis,highlighting the essential role of ER stress and CHOP in Cae A's anti-tumor mechanism.Both oxygen consumption rate(OCR)and extracellular acidification rate(ECAR)decreased in TNBC cells following Cae A treatment,indicating reduced mitochondrial respiratory and glycolytic capacities.This diminished energy metabolism potentially triggers ER stress and subsequent apoptosis.Furthermore,Cae A exhibited significant anti-tumor effects in the 4T1 tumor model in vivo without apparent toxicity.The compound also effectively inhibited human TNBC organoid growth.These results indicate that Cae A may serve as a potential therapeutic agent for TNBC,with its efficacy likely mediated through the disruption of glucose metabolism and the induction of ER stress-associated apoptosis.
文摘Actinomycetes have been prolific sources of novel secondary metabolites with a range of biological activities that may ultimately find application as therapeutic compounds. Hence several drug discovery companies are engaged in isolation of novel bioactive metabolites from these microbial sources. Antibiotics form the major class of such bioactive metabolites and have been widely used for treating infectious diseases. One of the most critical problems in clinical practice is the increase of prevalence of drug resistant strains, especially azole resistance among fungi. Due to this, there is a constant need for development of new antifungal antibiotics having novel scaffolds and/or mechanism of action. In our in-house screening program in the quest of novel and superior antifungal compounds, an actinomycetes strain PM0525875 was isolated from a marine invertebrate. The extracts of this microbe showed potent in-vitro antifungal activity against drug resistant fungal strains. The antifungal active peak from the extract obtained by shake flask fermentation was identified by chromatographic and other analytical techniques during bioactivity guided isolation. Later the fermentation conditions were optimized in 30 L fermentor for the production of sufficient amount antifungal compound for complete structural characterization. Consequently the fermented broth extract was subjected to bioactivity-guided fractionation, to isolate the active principle using different preparative chromatographic techniques followed by its characterization. The active principle was characterized to be Caerulomycin A. Minimum inhibitory concentration (MIC) of the compound was found in the range of 0.39 - 1.56 μg/ml against pathogenic fungal test strains. The phylogenetic analysis of producer strain using 16S rRNA sequence showed closest match with Actinoalloateichus cyanogriseus. Herewith we report the isolation of Caerulomycin A from marine invertebrate-associated Actinoalloteichus sp. using optimized medium and fermentation conditions.
基金This workwas supported in part by grants from NSFC(21472231,21520102004,31430005,and 81302674)CAS(SQYZDJ-SSWSLH1037 and XDB20020200)+1 种基金STCM(14JC1407700 and 15JC1400400)K.C.Wong Education Foundation and Chang-Jiang Scholars Program of China.
文摘2,20-Bipyridine(2,20-BiPy)is an attractive core structure present in a number of biologically active natural products,including the structurally related antibiotics caerulomycins(CAEs)and collismycins(COLs).Their biosynthetic pathways share a similar key 2,20-BiPy-L-leucine intermediate,which is desulfurated or sulfurated at C5,arises from a polyketide synthase/nonribosomal peptide synthetase hybrid assembly line.Focusing on the common off-line modification steps,we here report that the removal of the“auxiliary”L-leucine residue relies on the metallo-dependent amidohydrolase activity of CaeD or ColD.This activity leads to the production of similar 2,20-BiPy carboxylate products that then receive an oxime functionality that is characteristic for both CAEs and COLs.Unlike many metallo-dependent amidohydrolase superfamily proteins that have been previously reported,these proteins(particularly CaeD)exhibited a strong zinc ion-binding capacity that was proven by site-specific mutagenesis studies to be essential to proteolytic activity.The kinetics of the conversions that respectively involve CaeD and ColD were analyzed,showing the differences in the efficiency and substrate specificity of these two proteins.These findings would generate interest in the metallo-dependent amidohydrolase superfamily proteins that are involved in the biosynthesis of bioactive natural products.
