Predatory bacteria – can they succeed where antibiotics do not work?

Predatorske bakterije daju nadu za zaustavljanje mnogih patogenih bakterija, od kojih su neke postale otporne na do sada poznate antibiotike i uzrokuju velike probleme, pogotovo u slučaju bolničkih infekcija. Dosadašnja istraživanja su pokazala da značajno reduciraju broj nekih od najpoznatijih patogenih bakterija poput vrste Klebsiella pneumoniae, uzročnika atipične upale pluća, ali i oportunističkog patogena koji može uzrokovati infekcije rana i urinarnog trakta, najčešće stečene u bolnici. Njihova je prednost i u tome što napadaju samo određene bakterijske vrste, što znači da u slučaju upotrebe kao živog antibiotika neće ubijati bakterije koje normalno žive u ljudskom tijelu, niti štetiti ljudima jer ne mogu napadati stanice sisavaca. Dosadašnja istraživanja pokazuju da nije moguć prijenos gena između predatora i plijena, pa se smatra malo vjerojatnim da bi predator mogao postati patogenim za ljude ili druge sisavce. Za razliku od standardnih antibiotika, takav živi antibiotik mogao bi evoluirati paralelno sa svojim plijenom, te plijen ne bi mogao postati rezistentan; bar ne zadugo. Ipak, čini se da se raspon plijena za neke predatore može povećati, što je jedna od glavnih tema novijih istraživanja. Drugi aspekti koje znanstvenici trebaju detaljno istražiti prije početka upotrebe predatorskih bakterija kao antibiotika jesu sve posljedice koje bi moglo imati unošenje stranog organizma u ljudsko tijelo.Predatory bacteria raise hope for stopping a multitude of pathogenic bacteria, some of which have become resistant to currently used antibiotics and cause severe problems, primarily related to hospital-acquired infections. Research conducted so far has shown that predatory bacteria have the ability to significantly reduce some of the most famous pathogenic bacteria, such as Klebsiella pneumoniae, cause of an atypical pneumonia, but also an opportunistic pathogen that can cause urinary and wound infection, most commonly hospital-acquired. Another advantage of predatory bacteria is their tendency to attack only some species of bacteria. Therefore, if used as a living antibiotic they will not kill bacteria that are normal habitants of the human body, nor can they be harmful to humans as they cannot attack mammalian cells. Up to this date a case of gene transfer between the predatory bacteria and its prey hasn't been recorded, so it is considered unlikely for the predator to become pathogenic for humans or other mammals. Unlike standard antibiotics, a living antibiotic could evolve simultaneously with its prey, which would mean that the prey could not become resistant to it, at least not for long

Predatory bacteria – can they succeed where antibiotics do not work?

Predatorske bakterije daju nadu za zaustavljanje mnogih patogenih bakterija, od kojih su neke postale otporne na do sada poznate antibiotike i uzrokuju velike probleme, pogotovo u slučaju bolničkih infekcija. Dosadašnja istraživanja su pokazala da značajno reduciraju broj nekih od najpoznatijih patogenih bakterija poput vrste Klebsiella pneumoniae, uzročnika atipične upale pluća, ali i oportunističkog patogena koji može uzrokovati infekcije rana i urinarnog trakta, najčešće stečene u bolnici. Njihova je prednost i u tome što napadaju samo određene bakterijske vrste, što znači da u slučaju upotrebe kao živog antibiotika neće ubijati bakterije koje normalno žive u ljudskom tijelu, niti štetiti ljudima jer ne mogu napadati stanice sisavaca. Dosadašnja istraživanja pokazuju da nije moguć prijenos gena između predatora i plijena, pa se smatra malo vjerojatnim da bi predator mogao postati patogenim za ljude ili druge sisavce. Za razliku od standardnih antibiotika, takav živi antibiotik mogao bi evoluirati paralelno sa svojim plijenom, te plijen ne bi mogao postati rezistentan; bar ne zadugo. Ipak, čini se da se raspon plijena za neke predatore može povećati, što je jedna od glavnih tema novijih istraživanja. Drugi aspekti koje znanstvenici trebaju detaljno istražiti prije početka upotrebe predatorskih bakterija kao antibiotika jesu sve posljedice koje bi moglo imati unošenje stranog organizma u ljudsko tijelo.Predatory bacteria raise hope for stopping a multitude of pathogenic bacteria, some of which have become resistant to currently used antibiotics and cause severe problems, primarily related to hospital-acquired infections. Research conducted so far has shown that predatory bacteria have the ability to significantly reduce some of the most famous pathogenic bacteria, such as Klebsiella pneumoniae, cause of an atypical pneumonia, but also an opportunistic pathogen that can cause urinary and wound infection, most commonly hospital-acquired. Another advantage of predatory bacteria is their tendency to attack only some species of bacteria. Therefore, if used as a living antibiotic they will not kill bacteria that are normal habitants of the human body, nor can they be harmful to humans as they cannot attack mammalian cells. Up to this date a case of gene transfer between the predatory bacteria and its prey hasn't been recorded, so it is considered unlikely for the predator to become pathogenic for humans or other mammals. Unlike standard antibiotics, a living antibiotic could evolve simultaneously with its prey, which would mean that the prey could not become resistant to it, at least not for long

Predatory bacteria – can they succeed where antibiotics do not work?

Predatorske bakterije daju nadu za zaustavljanje mnogih patogenih bakterija, od kojih su neke postale otporne na do sada poznate antibiotike i uzrokuju velike probleme, pogotovo u slučaju bolničkih infekcija. Dosadašnja istraživanja su pokazala da značajno reduciraju broj nekih od najpoznatijih patogenih bakterija poput vrste Klebsiella pneumoniae, uzročnika atipične upale pluća, ali i oportunističkog patogena koji može uzrokovati infekcije rana i urinarnog trakta, najčešće stečene u bolnici. Njihova je prednost i u tome što napadaju samo određene bakterijske vrste, što znači da u slučaju upotrebe kao živog antibiotika neće ubijati bakterije koje normalno žive u ljudskom tijelu, niti štetiti ljudima jer ne mogu napadati stanice sisavaca. Dosadašnja istraživanja pokazuju da nije moguć prijenos gena između predatora i plijena, pa se smatra malo vjerojatnim da bi predator mogao postati patogenim za ljude ili druge sisavce. Za razliku od standardnih antibiotika, takav živi antibiotik mogao bi evoluirati paralelno sa svojim plijenom, te plijen ne bi mogao postati rezistentan; bar ne zadugo. Ipak, čini se da se raspon plijena za neke predatore može povećati, što je jedna od glavnih tema novijih istraživanja. Drugi aspekti koje znanstvenici trebaju detaljno istražiti prije početka upotrebe predatorskih bakterija kao antibiotika jesu sve posljedice koje bi moglo imati unošenje stranog organizma u ljudsko tijelo.Predatory bacteria raise hope for stopping a multitude of pathogenic bacteria, some of which have become resistant to currently used antibiotics and cause severe problems, primarily related to hospital-acquired infections. Research conducted so far has shown that predatory bacteria have the ability to significantly reduce some of the most famous pathogenic bacteria, such as Klebsiella pneumoniae, cause of an atypical pneumonia, but also an opportunistic pathogen that can cause urinary and wound infection, most commonly hospital-acquired. Another advantage of predatory bacteria is their tendency to attack only some species of bacteria. Therefore, if used as a living antibiotic they will not kill bacteria that are normal habitants of the human body, nor can they be harmful to humans as they cannot attack mammalian cells. Up to this date a case of gene transfer between the predatory bacteria and its prey hasn't been recorded, so it is considered unlikely for the predator to become pathogenic for humans or other mammals. Unlike standard antibiotics, a living antibiotic could evolve simultaneously with its prey, which would mean that the prey could not become resistant to it, at least not for long

Complex formation between mutant p53 and protein p63 in human tumor cell lines

Tumor supresorski gen TP53 mutiran je u preko 50% tumora čovjeka. Nakon mutacije može doći do gubitka funkcije p53 u stanici, ali i do promjene funkcije p53, koji može pokazivati onkogena svojstva. Neka onkogena svojstva mutiranih p53 mogu se objasniti interakcijom s drugim članovima obitelji p53, posebice s tumor supresorskim izoformama, TAp63 i TAp73. Na jačinu tih interakcija utječe polimorfizam na kodonu 72 gena TP53. Plazmidni vektori s ugrađenim genom za TAp63α, odnosno s genom za mutirani p53 koji imaju različit polimorfizam na kodonu 72 kotransfecirani su u stanice metastaza karcinoma pluća čovjeka (H1299) koje imaju djelomičnu deleciju gena TP53. Proteinski kompleksi su izolirani iz staničnih lizata metodom ko-imunoprecipitacije i analizirani metodom western blotting. Kompleksi su utvrđeni za mutirane oblike p53 L194F i R282W, te nisu utvrđeni za R175H, R280K i I332A. Ustanovljeno je da se mut p53 72R jače veže za TAp63α nego mut p53 72P.The tumor suppressor gene TP53 is mutated in over 50% of reported human tumor cases. The outcomes of the mutation are either loss of p53 function or gain of function resulting in oncogenic phenotype. Some of the mutant p53 oncogenic features are explained through interactions with other p53 family members, specifically tumor suppressor isoforms TAp63 and TAp73. A common polymorphism on codon 72 affects the strength of these interactions. Expression vectors coding for TAp63α or mutant p53 with different codon 72 polymorphism were cotransfected into H1299 cells, derived from human lung carcinoma metastasis, which have a partial deletion of the TP53 gene. Protein complexes were isolated from cell lysates using the co-immunoprecipitation method, and analysed by western blotting. Complexes have been found between TAp63α and p53 mutants L194F and R282W, but not between TAp63α and R175H, R280K and I332A. It was established that mut p53 72R binds more efficiently to TAp63α

Complex formation between mutant p53 and protein p63 in human tumor cell lines

Tumor supresorski gen TP53 mutiran je u preko 50% tumora čovjeka. Nakon mutacije može doći do gubitka funkcije p53 u stanici, ali i do promjene funkcije p53, koji može pokazivati onkogena svojstva. Neka onkogena svojstva mutiranih p53 mogu se objasniti interakcijom s drugim članovima obitelji p53, posebice s tumor supresorskim izoformama, TAp63 i TAp73. Na jačinu tih interakcija utječe polimorfizam na kodonu 72 gena TP53. Plazmidni vektori s ugrađenim genom za TAp63α, odnosno s genom za mutirani p53 koji imaju različit polimorfizam na kodonu 72 kotransfecirani su u stanice metastaza karcinoma pluća čovjeka (H1299) koje imaju djelomičnu deleciju gena TP53. Proteinski kompleksi su izolirani iz staničnih lizata metodom ko-imunoprecipitacije i analizirani metodom western blotting. Kompleksi su utvrđeni za mutirane oblike p53 L194F i R282W, te nisu utvrđeni za R175H, R280K i I332A. Ustanovljeno je da se mut p53 72R jače veže za TAp63α nego mut p53 72P.The tumor suppressor gene TP53 is mutated in over 50% of reported human tumor cases. The outcomes of the mutation are either loss of p53 function or gain of function resulting in oncogenic phenotype. Some of the mutant p53 oncogenic features are explained through interactions with other p53 family members, specifically tumor suppressor isoforms TAp63 and TAp73. A common polymorphism on codon 72 affects the strength of these interactions. Expression vectors coding for TAp63α or mutant p53 with different codon 72 polymorphism were cotransfected into H1299 cells, derived from human lung carcinoma metastasis, which have a partial deletion of the TP53 gene. Protein complexes were isolated from cell lysates using the co-immunoprecipitation method, and analysed by western blotting. Complexes have been found between TAp63α and p53 mutants L194F and R282W, but not between TAp63α and R175H, R280K and I332A. It was established that mut p53 72R binds more efficiently to TAp63α

Large-Scale Phosphoproteomics Reveals Shp-2 Phosphatase-Dependent Regulators of Pdgf Receptor Signaling

Summary: Despite its low cellular abundance, phosphotyrosine (pTyr) regulates numerous cell signaling pathways in health and disease. We applied comprehensive phosphoproteomics to unravel differential regulators of receptor tyrosine kinase (RTK)-initiated signaling networks upon activation by Pdgf-ββ, Fgf-2, or Igf-1 and identified more than 40,000 phosphorylation sites, including many phosphotyrosine sites without additional enrichment. The analysis revealed RTK-specific regulation of hundreds of pTyr sites on key signaling molecules. We found the tyrosine phosphatase Shp-2 to be the master regulator of Pdgfr pTyr signaling. Application of a recently introduced allosteric Shp-2 inhibitor revealed global regulation of the Pdgf-dependent tyrosine phosphoproteome, which significantly impaired cell migration. In addition, we present a list of hundreds of Shp-2-dependent targets and putative substrates, including Rasa1 and Cortactin with increased pTyr and Gab1 and Erk1/2 with decreased pTyr. Our study demonstrates that large-scale quantitative phosphoproteomics can precisely dissect tightly regulated kinase-phosphatase signaling networks. : Batth et al. use mass spectrometry-based phosphoproteomics to analyze receptor tyrosine kinase signaling activated by different ligands, identifying hundreds of differentially regulated phosphotyrosine sites. Tyrosine phosphatase Shp-2 regulates global tyrosine phosphorylation in a Pdgf-receptor-dependent manner, affecting cellular outcomes. Keywords: phosphoproteomics, Shp-2, PDGF, SHP099, Q exactive, orbitrap, label-free quantitation, tyrosine phosphorylation, TiO2, mass spectrometr

Phosphorylation of SHP2 at Tyr62 enables acquired resistance to SHP2 allosteric inhibitors in FLT3-ITD-driven AML

The protein tyrosine phosphatase SHP2 is crucial for oncogenic transformation of acute myeloid leukemia (AML) cells expressing mutated receptor tyrosine kinases (RTK). SHP2 is required for full RAS-ERK activation to promote cell proliferation and survival programs. Allosteric SHP2 inhibitors act by stabilizing SHP2 in its auto-inhibited conformation and are currently being tested in clinical trials for tumors with overactivation of the RAS/ERK pathway, alone and in various drug combinations. In this study, we established cells with acquired resistance to the allosteric SHP2 inhibitor SHP099 from two FLT3-ITD-positive AML cell lines. Label-free and isobaric labeling quantitative mass spectrometry-based phosphoproteomics of these resistant models demonstrated that AML cells can restore phosphorylated ERK (pERK) in the presence of SHP099, thus developing adaptive resistance. Mechanistically, SHP2 inhibition induced tyrosine phosphorylation and feedback-driven activation of the FLT3 receptor, which in turn phosphorylated SHP2 on tyrosine 62. This phosphorylation stabilized SHP2 in its open conformation, preventing SHP099 binding and conferring resistance. Combinatorial inhibition of SHP2 and MEK or FLT3 prevented pERK rebound and resistant cell growth. The same mechanism was observed in a FLT3-mutated B-ALL cell line and in the inv(16)/Kit(D816Y) AML mouse model, but allosteric inhibition of Shp2 did not impair the clonogenic ability of normal bone marrow progenitors. Together, these results support the future use of SHP2 inhibitor combinations for clinical applications