LOW EXPRESSION OF MIR-155 IN VINCRISTINE RESISTANT DIFFUSE LARGE B-CELL LYMPHOMA
(Abstract release date: 05/19/16)
EHA Library. Due Rasmussen H. 06/09/16; 132518; E969
Hanne Due Rasmussen
Contributions
Contributions
Abstract
Abstract: E969
Type: Eposter Presentation
Background
Vincristine is a key chemotherapeutic drug of first line therapy R-CHOP in Diffuse Large B-cell Lymphoma (DLBCL). The clinical course for DLBCL patients has great variability and an unfavorable outcome is observed in more than 40% of cases due to intrinsic or acquired treatment resistance. Accordingly, identification of molecular resistance mechanisms and early prediction of drug specific resistance is an urgent clinical need.
Aims
This study investigates the potential of miRNAs as predictive biomarkers of vincristine resistance and the involvement of miRNAs in the resistance mechanisms.
Methods
Systematic vincristine dose-response screen was performed on 12 DLBCL cell lines to identify 50% growth inhibition dose (GI50) for the individual cell lines. Ranking of GI50 allowed trichotomisation into groups of drug specific sensitive (n=3), intermediate (n=6), or resistant (n=3) cell lines. Based on global miRNA expression profiles of each cell line in untreated condition, class comparison was performed and 13 differentially expressed miRNAs were identified between sensitive and resistant cell lines (fold-change>׀2׀, p-value<0.05). Especially, miR-155 showed significant association between low expression and increased vincristine resistance having 33.5 fold decreased expression in resistant cell lines (p=0.0005).Based on gene expression profiles, 66 DLBCL patients biopsied at time of diagnosis were classified into the prognostic molecular subclasses ABC/GCB and B-cell associated gene signatures (BAGS), reflecting naturally occurring B-cell subsets of naïve, centroblast, centrocyte, memory, and plasmablast cells as cell of origin. Additionally, resistance gene signature (REGS) for vincristine was assigned to the clinical samples giving each case a likelihood of predicted response to vincristine. Expression levels of miR-155 were determined in the DLBCL samples by RT-qPCR.
Results
A significantly higher expression of miR-155 was observed in the prognostic adverse ABC subclass compared to GCB (n=66, p-value=0.0373) indicating miR-155 as an unfavorable marker. However, using BAGS classification clinical samples assigned into the prognostic favorable centrocyte subclass had higher miR-155 expression compared to the prognostic adverse centroblast subclass (n=59, p-value=0.003). Observations further supported when BAGS classification was stratified into ABC and GCB subclasses. Within the GCB subclass centrocyte DLBCL cases had significantly higher miR-155 expression compared to centroblast cases (n=27, p=0.0223). Within the ABC subclass no difference between the BAGS subclasses was detectable. Thus, using the prognostic BAGS classification system within the GCB subclass low miR-155 expression is an unfavorable marker. REGS stratification of clinical samples did not show significant miR-155 expression differences between REGS classes. However, assigning REGS to ABC and GCB subclasses, separately, a significant difference between low miR-155 expression and vincristine resistance was observed within the GCB subclass (n=27, p-value=0.051) but not within the ABC subclass (n=26, p-value=0.99). This supports the in vitro observations of low miR-155 expression and vincristine resistance within the GCB subclass.
Conclusion
In conclusion, we observed different miR-155 expression patterns between ABC and GCB subclasses. Moreover, a significant association between low miR-155 expression and vincristine resistance was demonstrated within GCB assigned cases. To unravel the biological mechanism determining miR-155 impact on vincristine resistance functional studies including expression manipulation in DLBCL cells with lentiviral vector system are ongoing.
Session topic: E-poster
Keyword(s): Chemoresistance, Diffuse large B cell lymphoma, Prediction
Type: Eposter Presentation
Background
Vincristine is a key chemotherapeutic drug of first line therapy R-CHOP in Diffuse Large B-cell Lymphoma (DLBCL). The clinical course for DLBCL patients has great variability and an unfavorable outcome is observed in more than 40% of cases due to intrinsic or acquired treatment resistance. Accordingly, identification of molecular resistance mechanisms and early prediction of drug specific resistance is an urgent clinical need.
Aims
This study investigates the potential of miRNAs as predictive biomarkers of vincristine resistance and the involvement of miRNAs in the resistance mechanisms.
Methods
Systematic vincristine dose-response screen was performed on 12 DLBCL cell lines to identify 50% growth inhibition dose (GI50) for the individual cell lines. Ranking of GI50 allowed trichotomisation into groups of drug specific sensitive (n=3), intermediate (n=6), or resistant (n=3) cell lines. Based on global miRNA expression profiles of each cell line in untreated condition, class comparison was performed and 13 differentially expressed miRNAs were identified between sensitive and resistant cell lines (fold-change>׀2׀, p-value<0.05). Especially, miR-155 showed significant association between low expression and increased vincristine resistance having 33.5 fold decreased expression in resistant cell lines (p=0.0005).Based on gene expression profiles, 66 DLBCL patients biopsied at time of diagnosis were classified into the prognostic molecular subclasses ABC/GCB and B-cell associated gene signatures (BAGS), reflecting naturally occurring B-cell subsets of naïve, centroblast, centrocyte, memory, and plasmablast cells as cell of origin. Additionally, resistance gene signature (REGS) for vincristine was assigned to the clinical samples giving each case a likelihood of predicted response to vincristine. Expression levels of miR-155 were determined in the DLBCL samples by RT-qPCR.
Results
A significantly higher expression of miR-155 was observed in the prognostic adverse ABC subclass compared to GCB (n=66, p-value=0.0373) indicating miR-155 as an unfavorable marker. However, using BAGS classification clinical samples assigned into the prognostic favorable centrocyte subclass had higher miR-155 expression compared to the prognostic adverse centroblast subclass (n=59, p-value=0.003). Observations further supported when BAGS classification was stratified into ABC and GCB subclasses. Within the GCB subclass centrocyte DLBCL cases had significantly higher miR-155 expression compared to centroblast cases (n=27, p=0.0223). Within the ABC subclass no difference between the BAGS subclasses was detectable. Thus, using the prognostic BAGS classification system within the GCB subclass low miR-155 expression is an unfavorable marker. REGS stratification of clinical samples did not show significant miR-155 expression differences between REGS classes. However, assigning REGS to ABC and GCB subclasses, separately, a significant difference between low miR-155 expression and vincristine resistance was observed within the GCB subclass (n=27, p-value=0.051) but not within the ABC subclass (n=26, p-value=0.99). This supports the in vitro observations of low miR-155 expression and vincristine resistance within the GCB subclass.
Conclusion
In conclusion, we observed different miR-155 expression patterns between ABC and GCB subclasses. Moreover, a significant association between low miR-155 expression and vincristine resistance was demonstrated within GCB assigned cases. To unravel the biological mechanism determining miR-155 impact on vincristine resistance functional studies including expression manipulation in DLBCL cells with lentiviral vector system are ongoing.
Session topic: E-poster
Keyword(s): Chemoresistance, Diffuse large B cell lymphoma, Prediction
Abstract: E969
Type: Eposter Presentation
Background
Vincristine is a key chemotherapeutic drug of first line therapy R-CHOP in Diffuse Large B-cell Lymphoma (DLBCL). The clinical course for DLBCL patients has great variability and an unfavorable outcome is observed in more than 40% of cases due to intrinsic or acquired treatment resistance. Accordingly, identification of molecular resistance mechanisms and early prediction of drug specific resistance is an urgent clinical need.
Aims
This study investigates the potential of miRNAs as predictive biomarkers of vincristine resistance and the involvement of miRNAs in the resistance mechanisms.
Methods
Systematic vincristine dose-response screen was performed on 12 DLBCL cell lines to identify 50% growth inhibition dose (GI50) for the individual cell lines. Ranking of GI50 allowed trichotomisation into groups of drug specific sensitive (n=3), intermediate (n=6), or resistant (n=3) cell lines. Based on global miRNA expression profiles of each cell line in untreated condition, class comparison was performed and 13 differentially expressed miRNAs were identified between sensitive and resistant cell lines (fold-change>׀2׀, p-value<0.05). Especially, miR-155 showed significant association between low expression and increased vincristine resistance having 33.5 fold decreased expression in resistant cell lines (p=0.0005).Based on gene expression profiles, 66 DLBCL patients biopsied at time of diagnosis were classified into the prognostic molecular subclasses ABC/GCB and B-cell associated gene signatures (BAGS), reflecting naturally occurring B-cell subsets of naïve, centroblast, centrocyte, memory, and plasmablast cells as cell of origin. Additionally, resistance gene signature (REGS) for vincristine was assigned to the clinical samples giving each case a likelihood of predicted response to vincristine. Expression levels of miR-155 were determined in the DLBCL samples by RT-qPCR.
Results
A significantly higher expression of miR-155 was observed in the prognostic adverse ABC subclass compared to GCB (n=66, p-value=0.0373) indicating miR-155 as an unfavorable marker. However, using BAGS classification clinical samples assigned into the prognostic favorable centrocyte subclass had higher miR-155 expression compared to the prognostic adverse centroblast subclass (n=59, p-value=0.003). Observations further supported when BAGS classification was stratified into ABC and GCB subclasses. Within the GCB subclass centrocyte DLBCL cases had significantly higher miR-155 expression compared to centroblast cases (n=27, p=0.0223). Within the ABC subclass no difference between the BAGS subclasses was detectable. Thus, using the prognostic BAGS classification system within the GCB subclass low miR-155 expression is an unfavorable marker. REGS stratification of clinical samples did not show significant miR-155 expression differences between REGS classes. However, assigning REGS to ABC and GCB subclasses, separately, a significant difference between low miR-155 expression and vincristine resistance was observed within the GCB subclass (n=27, p-value=0.051) but not within the ABC subclass (n=26, p-value=0.99). This supports the in vitro observations of low miR-155 expression and vincristine resistance within the GCB subclass.
Conclusion
In conclusion, we observed different miR-155 expression patterns between ABC and GCB subclasses. Moreover, a significant association between low miR-155 expression and vincristine resistance was demonstrated within GCB assigned cases. To unravel the biological mechanism determining miR-155 impact on vincristine resistance functional studies including expression manipulation in DLBCL cells with lentiviral vector system are ongoing.
Session topic: E-poster
Keyword(s): Chemoresistance, Diffuse large B cell lymphoma, Prediction
Type: Eposter Presentation
Background
Vincristine is a key chemotherapeutic drug of first line therapy R-CHOP in Diffuse Large B-cell Lymphoma (DLBCL). The clinical course for DLBCL patients has great variability and an unfavorable outcome is observed in more than 40% of cases due to intrinsic or acquired treatment resistance. Accordingly, identification of molecular resistance mechanisms and early prediction of drug specific resistance is an urgent clinical need.
Aims
This study investigates the potential of miRNAs as predictive biomarkers of vincristine resistance and the involvement of miRNAs in the resistance mechanisms.
Methods
Systematic vincristine dose-response screen was performed on 12 DLBCL cell lines to identify 50% growth inhibition dose (GI50) for the individual cell lines. Ranking of GI50 allowed trichotomisation into groups of drug specific sensitive (n=3), intermediate (n=6), or resistant (n=3) cell lines. Based on global miRNA expression profiles of each cell line in untreated condition, class comparison was performed and 13 differentially expressed miRNAs were identified between sensitive and resistant cell lines (fold-change>׀2׀, p-value<0.05). Especially, miR-155 showed significant association between low expression and increased vincristine resistance having 33.5 fold decreased expression in resistant cell lines (p=0.0005).Based on gene expression profiles, 66 DLBCL patients biopsied at time of diagnosis were classified into the prognostic molecular subclasses ABC/GCB and B-cell associated gene signatures (BAGS), reflecting naturally occurring B-cell subsets of naïve, centroblast, centrocyte, memory, and plasmablast cells as cell of origin. Additionally, resistance gene signature (REGS) for vincristine was assigned to the clinical samples giving each case a likelihood of predicted response to vincristine. Expression levels of miR-155 were determined in the DLBCL samples by RT-qPCR.
Results
A significantly higher expression of miR-155 was observed in the prognostic adverse ABC subclass compared to GCB (n=66, p-value=0.0373) indicating miR-155 as an unfavorable marker. However, using BAGS classification clinical samples assigned into the prognostic favorable centrocyte subclass had higher miR-155 expression compared to the prognostic adverse centroblast subclass (n=59, p-value=0.003). Observations further supported when BAGS classification was stratified into ABC and GCB subclasses. Within the GCB subclass centrocyte DLBCL cases had significantly higher miR-155 expression compared to centroblast cases (n=27, p=0.0223). Within the ABC subclass no difference between the BAGS subclasses was detectable. Thus, using the prognostic BAGS classification system within the GCB subclass low miR-155 expression is an unfavorable marker. REGS stratification of clinical samples did not show significant miR-155 expression differences between REGS classes. However, assigning REGS to ABC and GCB subclasses, separately, a significant difference between low miR-155 expression and vincristine resistance was observed within the GCB subclass (n=27, p-value=0.051) but not within the ABC subclass (n=26, p-value=0.99). This supports the in vitro observations of low miR-155 expression and vincristine resistance within the GCB subclass.
Conclusion
In conclusion, we observed different miR-155 expression patterns between ABC and GCB subclasses. Moreover, a significant association between low miR-155 expression and vincristine resistance was demonstrated within GCB assigned cases. To unravel the biological mechanism determining miR-155 impact on vincristine resistance functional studies including expression manipulation in DLBCL cells with lentiviral vector system are ongoing.
Session topic: E-poster
Keyword(s): Chemoresistance, Diffuse large B cell lymphoma, Prediction
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