Contributions
Abstract: EP871
Type: E-Poster Presentation
Session title: Lymphoma Biology & Translational Research
Background
Diffuse large B cell lymphoma (DLBCL) is a frequent aggressive lymphoid neoplasm. Standard protocol consisting of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) has improved remission and survival rates in patients with DLBCL. Nevertheless, 30% of patients do not respond to the therapy with R-CHOP or relapse resulting in relapsed/refractory (R/R) disease. Currently, there are several protocols for the treatment of R/R-DLBCL including a combination of rituximab and bendamustine. However, survival rates in patients with R/R-DLBCL remain dismal and require improvement through introduction of novel drugs and combinations. Melphalan flufenamide (melflufen) is a novel peptide-drug conjugate that rapidly delivers cytotoxic alkylating payload inside tumor cells. This process is potentiated by aminopeptidases highly expressed in cancer cells. Therefore, prognostic significance of aminopeptidases in DLBCL and potency of melflufen were investigated in this study.
Aims
First, assess prognostic significance of aminopeptidase gene expression in DLBCL. Second, evaluate potency of melflufen in the models of high risk DLBCL.
Methods
Expression levels of aminopeptidase genes in patient samples was assessed using publicly available RNA-sequencing data (GSE125966). The prognostic significance of highly expressed aminopeptidase genes was further evaluated in R-CHOP-treated patients (N=692) with available gene expression and censored survival data (GSE31312, GSE83731). Three ABC (SU-DHL-2, U2932, NU-DUL-1) and nine GCB DLBCL (SU-DHL-4/5/8/10/16, DoHH2, DB, Toledo, RC-K8) cell lines were profiled for drug sensitivity to melflufen and standard of care (SoC) drugs doxorubicin and bendamustine using an assay quantifying living cells. The results were confirmed in vivo.
Results
Several aminopeptidase genes (ERAP1, ERAP2, LAP3, LNPEP, LTA4H, METAP1, METAP2, NPEPPS, RNPEP, XPNPEP1, XPNPEP3) showed high expression in DLBCL patient samples. Among these genes high expression of LNPEP (37.0 vs 50.4 month, HR 0.73, 95% CI 0.61-0.88, p<0.0001) and LAP3 (37.4 vs 49.2 month, HR0.76, 95% CI 0.63-0.91, p=0.0005) conferred inferior survival of DLBCL patients. Aminopeptidase-potentiated peptide-drug conjugate melflufen showed a superior cytotoxicity to doxorubicin and bendamustine in all cell lines tested (Wilcoxon paired test p<0.0001). Interestingly, TP53 status of DLBCL cells did not significantly affect the cytotoxicity of melflufen.
Conclusion
Our results showed high expression of several aminopeptidase genes in DLBCL. Moreover, elevated expression of LNPEP and LAP3 conferred significantly shorter survival in DLBCL patients. A novel peptide-drug conjugate melflufen potentiated by aminopeptidases showed a superior cytotoxicity to SoC drugs doxorubicin and bendamustine in a panel of eleven DLBCL cell lines. Low expression or mutations in TP53 gene status of cell lines did not show a major effect on melflufen’s cytotoxicity. Thus, melflufen may be suitable for treatment of high risk DLBCL.
Keyword(s):
Abstract: EP871
Type: E-Poster Presentation
Session title: Lymphoma Biology & Translational Research
Background
Diffuse large B cell lymphoma (DLBCL) is a frequent aggressive lymphoid neoplasm. Standard protocol consisting of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) has improved remission and survival rates in patients with DLBCL. Nevertheless, 30% of patients do not respond to the therapy with R-CHOP or relapse resulting in relapsed/refractory (R/R) disease. Currently, there are several protocols for the treatment of R/R-DLBCL including a combination of rituximab and bendamustine. However, survival rates in patients with R/R-DLBCL remain dismal and require improvement through introduction of novel drugs and combinations. Melphalan flufenamide (melflufen) is a novel peptide-drug conjugate that rapidly delivers cytotoxic alkylating payload inside tumor cells. This process is potentiated by aminopeptidases highly expressed in cancer cells. Therefore, prognostic significance of aminopeptidases in DLBCL and potency of melflufen were investigated in this study.
Aims
First, assess prognostic significance of aminopeptidase gene expression in DLBCL. Second, evaluate potency of melflufen in the models of high risk DLBCL.
Methods
Expression levels of aminopeptidase genes in patient samples was assessed using publicly available RNA-sequencing data (GSE125966). The prognostic significance of highly expressed aminopeptidase genes was further evaluated in R-CHOP-treated patients (N=692) with available gene expression and censored survival data (GSE31312, GSE83731). Three ABC (SU-DHL-2, U2932, NU-DUL-1) and nine GCB DLBCL (SU-DHL-4/5/8/10/16, DoHH2, DB, Toledo, RC-K8) cell lines were profiled for drug sensitivity to melflufen and standard of care (SoC) drugs doxorubicin and bendamustine using an assay quantifying living cells. The results were confirmed in vivo.
Results
Several aminopeptidase genes (ERAP1, ERAP2, LAP3, LNPEP, LTA4H, METAP1, METAP2, NPEPPS, RNPEP, XPNPEP1, XPNPEP3) showed high expression in DLBCL patient samples. Among these genes high expression of LNPEP (37.0 vs 50.4 month, HR 0.73, 95% CI 0.61-0.88, p<0.0001) and LAP3 (37.4 vs 49.2 month, HR0.76, 95% CI 0.63-0.91, p=0.0005) conferred inferior survival of DLBCL patients. Aminopeptidase-potentiated peptide-drug conjugate melflufen showed a superior cytotoxicity to doxorubicin and bendamustine in all cell lines tested (Wilcoxon paired test p<0.0001). Interestingly, TP53 status of DLBCL cells did not significantly affect the cytotoxicity of melflufen.
Conclusion
Our results showed high expression of several aminopeptidase genes in DLBCL. Moreover, elevated expression of LNPEP and LAP3 conferred significantly shorter survival in DLBCL patients. A novel peptide-drug conjugate melflufen potentiated by aminopeptidases showed a superior cytotoxicity to SoC drugs doxorubicin and bendamustine in a panel of eleven DLBCL cell lines. Low expression or mutations in TP53 gene status of cell lines did not show a major effect on melflufen’s cytotoxicity. Thus, melflufen may be suitable for treatment of high risk DLBCL.
Keyword(s):