Combinatory effects of cisplatin and 17AAG treatment in DLBCL
Author
Haraldsdóttir, Hulda
Term
4. term
Publication year
2022
Submitted on
2022-06-01
Pages
70
Abstract
Background: Cisplatin is an effective anticancer drug used as salvage (second-line) therapy for patients with diffuse large B-cell lymphoma (DLBCL) when the disease relapses or is refractory to first-line treatment (rrDLBCL). About 70% relapse again after salvage therapy, partly due to resistance to drugs such as cisplatin, leaving few options and a poor prognosis. Cisplatin resistance has been linked to overactivity of the DNA damage response (DDR), the cell’s system for detecting and repairing DNA damage. Inhibiting DDR during cisplatin treatment could therefore improve its effect. 17AAG is a potent Hsp90 inhibitor; by binding the Hsp90 complex it promotes degradation of client proteins, including DDR components, and has been considered as an add-on to cisplatin. Hypothesis and methods: We hypothesized that 17AAG can sensitize DLBCL cells to cisplatin and thereby overcome resistance. Two DLBCL cell lines, RIVA and SU-DHL-5, were treated with cisplatin and 17AAG as single agents and in combination, with vehicle controls. We assessed DNA damage, cell-cycle distribution, and apoptosis (programmed cell death) by flow cytometry, measured cell viability by cell counting, and monitored changes in DDR protein levels over time using quantitative proteomics. Results: In RIVA, combining 17AAG with cisplatin produced a synergistic effect: increased DNA damage, disrupted cell cycle, more apoptosis, and reduced viability. No synergy was seen in SU-DHL-5, suggesting cell-line-specific combination effects in resistant DLBCL cells such as RIVA. In both lines, 17AAG treatment was associated with a tendency toward lower levels of the DDR proteins MSH2 and MSH6, implying that the synergy may partly arise from DDR inhibition. Conclusion: 17AAG sensitizes cisplatin-resistant DLBCL cells to cisplatin, pointing to a potential strategy to overcome cisplatin resistance.
Baggrund: Cisplatin er et effektivt kræftlægemiddel, der bruges som andenlinjebehandling (redningsbehandling) til patienter med diffust storcellet B-celle lymfom (DLBCL), når sygdommen vender tilbage eller ikke reagerer på første behandling (rrDLBCL). Omkring 70% får dog igen tilbagefald efter redningsbehandling, blandt andet fordi tumorerne bliver resistente over for lægemidler som cisplatin. Det giver få behandlingsmuligheder og en dårlig prognose. Resistens mod cisplatin er sat i forbindelse med overaktivitet i cellens DNA-reparationsrespons (DNA damage response, DDR). At hæmme DDR, mens cisplatin gives, kan derfor muligvis øge effekten. 17AAG er en stærk Hsp90-hæmmer; ved at binde til Hsp90-komplekset fremmer den nedbrydning af klientproteiner, herunder DDR-komponenter, og er derfor overvejet som tillæg til cisplatin. Hypotese og metode: Vi antog, at 17AAG kan gøre DLBCL-celler mere følsomme over for cisplatin og dermed overvinde resistens. To DLBCL-cellelinjer, RIVA og SU-DHL-5, blev behandlet med cisplatin og 17AAG hver for sig og i kombination samt med kontrol. Vi målte DNA-skade, fordeling i cellecyklus og apoptose (programmeret celledød) med gennemstrømningscytometri, bestemte cellers levedygtighed ved celletælling og fulgte ændringer i DDR-proteiners niveauer over tid med kvantitativ proteomik. Resultater: I RIVA gav kombinationen af 17AAG og cisplatin en synergistisk virkning: mere DNA-skade, forstyrret cellecyklus, øget apoptose og lavere levedygtighed. I SU-DHL-5 sås ingen synergi, hvilket tyder på cellelinje-specifikke kombinationseffekter i resistente DLBCL-celler som RIVA. I begge cellelinjer sås desuden en tendens til lavere niveauer af DDR-proteinerne MSH2 og MSH6 efter 17AAG-behandling, hvilket indikerer, at kombinationseffekten delvist kan skyldes hæmning af DDR. Konklusion: 17AAG gør cisplatin-resistente DLBCL-celler mere følsomme for cisplatin og kan dermed udgøre en mulig strategi til at overvinde cisplatinresistens.
[This apstract has been rewritten with the help of AI based on the project's original abstract]
Keywords
DLBCL ; DDR ; Cisplatin ; Hsp90 inhibitor ; Resistance