Pancreatic cancer (PC) is one of the most lethal solid cancers in these days. The high metastatic activity at an early stage and the lack of early diagnosis techniques, lead to a concerning high mortality rate in developed countries, strictly parallel to its incidence. In fact, PC is often diagnosed after the development of metastases and when the disease is no longer operable. Smoking, genetic vulnerability, obesity, diabetes mellitus, alcohol, and consumption of processed meat are known risk factors for cancer. Specifically, pancreatitis and another inflammation / infectious disease have been associated with a higher risk to develop PC. Growing evidence suggests that there is an association between bacteria and PC, not only in the pathogenesis, but also in the antagonism to drug therapies. This thesis focuses on the study of the association between a bacterial infection and PC. It aims to assess the growth of a microbial population, which has infected a tumour tissue, and wether it can be influenced by the cellular behaviours associated with tumour progression. To establish a reliable tissue culture model system, we defined the growth curves of the bacteria Staphylococcus aureus (S. aureus). We determined their growth kinetics in standard and non-standard growth conditions. We also established optimal growth parameters of the PANC-1 tumour eukaryotic cell cultures. Finally, an in vitro culture model was developed that would allow the coexistence of tumour cells and bacteria using different infections ratios, through which the bacterial growth of S. aureus was quantified. The acquired data highlighted the various phases of bacterial growth: exponential, stationery, and death. It was evident that S. aureus could grow in both bacterial- and tissue culture medium with equal growth kinetics. The analysis of the co-culture of bacteria and cancer cells highlighted the growth of S. aureus in the presence of tumour cells after 24 hours. Although numerous studies indicate that pancreatic ductal adenocarcinoma (PDAC) is associated with microbes, their role needs to be further explored in order to attribute a causative, parallel or consequential contribution to this lethal disease. In fact, the composition of the microbiota could represent a non-invasive screening method, influence future toxicological research in the pharmaceutical sector and help in the discovery of targeted therapies. Not only new probiotics could be developed and used in conjunction with chemo- and immunotherapy, but also, the fabrication of personalised medicines would be established.
Il cancro al pancreas (PC) è, ad oggi, uno dei tumori solidi con più alto grado di letalità. L'elevata attività metastatica in fase iniziale e la mancanza di tecniche di diagnosi precoce, portano ad un tasso di mortalità relativamente alto nei paesi sviluppati, strettamente parallelo alla sua incidenza. Infatti, il PC viene spesso diagnosticato dopo lo sviluppo di metastasi e quando la malattia non è più operabile. Il fumo, la vulnerabilità genetica, l'obesità, il diabete mellito, l'alcol e il consumo di carne lavorata sono noti fattori di rischio per il cancro. Prove crescenti suggeriscono che esiste un'associazione tra batteri e PC, non solo nella patogenesi, ma anche nell'antagonismo alle terapie farmacologiche. Il presente lavoro di tesi si colloca nell’ambito di una ricerca volta ad approfondire la potenziale associazione tra un'infezione batterica e il PC. Mira a valutare se e come la crescita di una popolazione microbica, che ha infettato un tessuto tumorale, può essere influenzata dai comportamenti cellulari associati alla progressione del tumore. Per stabilire un modello affidabile di coltura tissutale, abbiamo definito le curve di crescita dei batteri Staphylococcus aureus (S.aureus). Abbiamo determinato la loro cinetica di crescita in condizioni di crescita standard e non standard. Abbiamo anche stabilito parametri di crescita ottimali delle colture cellulari eucariotiche tumorali PANC-1. È stato, infine, sviluppato un modello di coltura in vitro che consentisse la coesistenza di cellule tumorali e batteri, utilizzando diversi rapporti di infezione, attraverso il quale è stata quantificata la crescita batterica di S.aureus. I dati acquisiti hanno evidenziato le varie fasi della crescita batterica: esponenziale, stazionaria e di morte. È risultato evidente che S.aureus poteva crescere sia nel mezzo di coltura batterica che tissutale, con cinetica di crescita uguale. L'analisi della co-coltura di batteri e cellule tumorali ha evidenziato la crescita di S.aureus in presenza di cellule tumorali dopo 24 ore. Sebbene numerosi studi indichino che l'adenocarcinoma duttale pancreatico (PDAC) sia associato a microbi, il loro ruolo deve essere ulteriormente esplorato per attribuire un contributo causale, parallelo o consequenziale a questa malattia letale. La composizione del microbiota, infatti, potrebbe rappresentare un metodo di screening non invasivo, influenzare la futura ricerca tossicologica nel settore farmaceutico e aiutare nella scoperta di terapie mirate. Non solo nuovi probiotici potrebbero essere sviluppati e utilizzati in combinazione con chemio e immunoterapia, ma sarebbe anche istituita la fabbricazione di medicinali personalizzati.
Cancro al pancreas: possibile ruolo dei batteri nell'insorgenza e nello sviluppo del cancro
SPOTO, GIULIA
2020/2021
Abstract
Pancreatic cancer (PC) is one of the most lethal solid cancers in these days. The high metastatic activity at an early stage and the lack of early diagnosis techniques, lead to a concerning high mortality rate in developed countries, strictly parallel to its incidence. In fact, PC is often diagnosed after the development of metastases and when the disease is no longer operable. Smoking, genetic vulnerability, obesity, diabetes mellitus, alcohol, and consumption of processed meat are known risk factors for cancer. Specifically, pancreatitis and another inflammation / infectious disease have been associated with a higher risk to develop PC. Growing evidence suggests that there is an association between bacteria and PC, not only in the pathogenesis, but also in the antagonism to drug therapies. This thesis focuses on the study of the association between a bacterial infection and PC. It aims to assess the growth of a microbial population, which has infected a tumour tissue, and wether it can be influenced by the cellular behaviours associated with tumour progression. To establish a reliable tissue culture model system, we defined the growth curves of the bacteria Staphylococcus aureus (S. aureus). We determined their growth kinetics in standard and non-standard growth conditions. We also established optimal growth parameters of the PANC-1 tumour eukaryotic cell cultures. Finally, an in vitro culture model was developed that would allow the coexistence of tumour cells and bacteria using different infections ratios, through which the bacterial growth of S. aureus was quantified. The acquired data highlighted the various phases of bacterial growth: exponential, stationery, and death. It was evident that S. aureus could grow in both bacterial- and tissue culture medium with equal growth kinetics. The analysis of the co-culture of bacteria and cancer cells highlighted the growth of S. aureus in the presence of tumour cells after 24 hours. Although numerous studies indicate that pancreatic ductal adenocarcinoma (PDAC) is associated with microbes, their role needs to be further explored in order to attribute a causative, parallel or consequential contribution to this lethal disease. In fact, the composition of the microbiota could represent a non-invasive screening method, influence future toxicological research in the pharmaceutical sector and help in the discovery of targeted therapies. Not only new probiotics could be developed and used in conjunction with chemo- and immunotherapy, but also, the fabrication of personalised medicines would be established.È consentito all'utente scaricare e condividere i documenti disponibili a testo pieno in UNITESI UNIPV nel rispetto della licenza Creative Commons del tipo CC BY NC ND.
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https://hdl.handle.net/20.500.14239/14231