Studying the role of BCL2 and MYC in the pathogenesis of diffuse large B cell lymphoma
Approximately 30% of patients with diffuse large B-cell lymphoma (DLBCL) co-express BCL2 and MYC, known as double-expressor lymphomas (DEL). These lymphomas associate with poorer prognosis and response to standard-of-care R-CHOP, and a preferred therapeutic alternative has not been identified yet...
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| Format: | info:eu-repo/semantics/doctoralThesis |
| Language: | eng |
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Universidad de Navarra
2023
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| Subjects: | |
| Online Access: | https://hdl.handle.net/10171/68058 |
| _version_ | 1793400538294910976 |
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| author | Sánchez, J. (Javier) Martinez-Climent, J.A. (José Ángel) Roa, S. (Sergio) |
| author_facet | Sánchez, J. (Javier) Martinez-Climent, J.A. (José Ángel) Roa, S. (Sergio) |
| author_sort | Sánchez, J. (Javier) |
| collection | DSpace |
| description | Approximately 30% of patients with diffuse large B-cell lymphoma (DLBCL) co-express BCL2
and MYC, known as double-expressor lymphomas (DEL). These lymphomas associate with
poorer prognosis and response to standard-of-care R-CHOP, and a preferred therapeutic
alternative has not been identified yet.
There are very interesting ongoing clinical trials to evaluate the potential of venetoclax to
inhibit the anti-apoptotic protein BCL2 in high grade B cell lymphomas. Additionally, there
are investigations ongoing trying to find a MYC inhibitor that can be efficiently used in the
clinic without secondary effects. Here, we aimed to provide complementary preclinical in
vivo evidences for these investigations, modelling this DEL-scenario in new mouse models
and demonstrating that combination of anti-CD20 with BCL2 or MYC specific inhibitors can
improve long-term survival in BCL2/MYC-expressor DLBCL mice.
For this, we first generated and characterized three multi-transgenic mouse models and
further demonstrated that it is possible to successfully recapitulate the complex
progression and tumor microenvironment of DEL-DLBCL in the murine setting,
recapitulating the classical genetic alterations of these patients by conditional mutagenesis
at early stages of the germinal center reaction. We then demonstrated that lymphomas in
these mice rapidly acquire aberrant BCL2/MYC co-expression and impair apoptosis during
NF-κB-driven malignant transformation of germinal center B cells, hindering DLBCL cells
sensitive to inhibition of BCL2 (with venetoclax) or MYC (with MYCi975).
Then, we provided in vivo evidences that combination of venetoclax with anti-CD20-based
immunotherapy can result in synergistic anti-lymphoma effects and extended overall
survival of mice. Not only we demonstrated specific cell killing of BCL2/MYC co-expressing
lymphoma cells in response to the combination treatment; but also, we revealed, for the
first time in DLBCL, that venetoclax can promote the enrichment of activated intratumoral
effector/effector memory CD8+ T cells, exhibiting additional immunomodulatory potential
in the DEL-DLBCL tumor microenvironment.
In addition, we demonstrated that acceleration of lymphomagenesis was evidenced when
MYC expression was enforced from early stages of germinal center reaction. However, this
lymphomagenesis was accompanied by the appearance of non-B-cells gastrointestinal
tumors, possibly driven by the leakage of MYC expression, hence, resulting resistant to the
conventional anti-CD20 immunotherapeutic regimen and to antibiotic treatment, impairing
overall survival.
Altogether, our results strongly support pre-clinical proof-of-concept and rationale for
incorporating venetoclax to anti-CD20-based treatments to improve the outcome of
aggressive DEL-DLBCL, and provide evidences for future combinations with specific MYC
inhibitors, either incorporating them to the actual gold-standard R-CHOP or by dual
targeting the Achilles heels of tumor cells through combined BCL2 and MYC specific
inhibition. These preclinical combinations could either be performed in our murine models
or in the novel 3D culture technique that we have successfully implemented here, which
allows the long-term culture of lymphoma cells with its tumor microenvironment in the
form of tumor spheroids and could serve as an ex vivo platform for future screening of novel
therapeutic strategies in DLBCL. |
| format | info:eu-repo/semantics/doctoralThesis |
| id | oai:dadun.unav.edu:10171-68058 |
| institution | Universidad de Navarra |
| language | eng |
| publishDate | 2023 |
| publisher | Universidad de Navarra |
| record_format | dspace |
| spelling | oai:dadun.unav.edu:10171-680582024-02-08T10:47:50Z Studying the role of BCL2 and MYC in the pathogenesis of diffuse large B cell lymphoma Sánchez, J. (Javier) Martinez-Climent, J.A. (José Ángel) Roa, S. (Sergio) Materias Investigacion::Ciencias de la Salud::Genética Diffuse large B cell lymphoma BCL2 MYC B-Cell lymphomagenesis Linfoma difuso de células B Approximately 30% of patients with diffuse large B-cell lymphoma (DLBCL) co-express BCL2 and MYC, known as double-expressor lymphomas (DEL). These lymphomas associate with poorer prognosis and response to standard-of-care R-CHOP, and a preferred therapeutic alternative has not been identified yet. There are very interesting ongoing clinical trials to evaluate the potential of venetoclax to inhibit the anti-apoptotic protein BCL2 in high grade B cell lymphomas. Additionally, there are investigations ongoing trying to find a MYC inhibitor that can be efficiently used in the clinic without secondary effects. Here, we aimed to provide complementary preclinical in vivo evidences for these investigations, modelling this DEL-scenario in new mouse models and demonstrating that combination of anti-CD20 with BCL2 or MYC specific inhibitors can improve long-term survival in BCL2/MYC-expressor DLBCL mice. For this, we first generated and characterized three multi-transgenic mouse models and further demonstrated that it is possible to successfully recapitulate the complex progression and tumor microenvironment of DEL-DLBCL in the murine setting, recapitulating the classical genetic alterations of these patients by conditional mutagenesis at early stages of the germinal center reaction. We then demonstrated that lymphomas in these mice rapidly acquire aberrant BCL2/MYC co-expression and impair apoptosis during NF-κB-driven malignant transformation of germinal center B cells, hindering DLBCL cells sensitive to inhibition of BCL2 (with venetoclax) or MYC (with MYCi975). Then, we provided in vivo evidences that combination of venetoclax with anti-CD20-based immunotherapy can result in synergistic anti-lymphoma effects and extended overall survival of mice. Not only we demonstrated specific cell killing of BCL2/MYC co-expressing lymphoma cells in response to the combination treatment; but also, we revealed, for the first time in DLBCL, that venetoclax can promote the enrichment of activated intratumoral effector/effector memory CD8+ T cells, exhibiting additional immunomodulatory potential in the DEL-DLBCL tumor microenvironment. In addition, we demonstrated that acceleration of lymphomagenesis was evidenced when MYC expression was enforced from early stages of germinal center reaction. However, this lymphomagenesis was accompanied by the appearance of non-B-cells gastrointestinal tumors, possibly driven by the leakage of MYC expression, hence, resulting resistant to the conventional anti-CD20 immunotherapeutic regimen and to antibiotic treatment, impairing overall survival. Altogether, our results strongly support pre-clinical proof-of-concept and rationale for incorporating venetoclax to anti-CD20-based treatments to improve the outcome of aggressive DEL-DLBCL, and provide evidences for future combinations with specific MYC inhibitors, either incorporating them to the actual gold-standard R-CHOP or by dual targeting the Achilles heels of tumor cells through combined BCL2 and MYC specific inhibition. These preclinical combinations could either be performed in our murine models or in the novel 3D culture technique that we have successfully implemented here, which allows the long-term culture of lymphoma cells with its tumor microenvironment in the form of tumor spheroids and could serve as an ex vivo platform for future screening of novel therapeutic strategies in DLBCL. Aproximadamente un 30% de los pacientes con linfoma difuso de células B grandes (LDCBG) co-expresan BCL2 y MYC, los cuales se conocen como linfomas doble-expresantes (LDE). Estos linfomas se asocian con peor pronóstico y presentan peor respuesta al tratamiento estándar R-CHOP, y todavía no se han encontrado alternativas terapéuticas. Hay varios ensayos clínicos en marcha que evalúan el potencial de venetoclax para inhibir la proteína anti-apoptótica BCL2 en los linfomas de alto grado. También hay investigaciones en curso que intentan encontrar inhibidores específicos de MYC que se puedan usar de forma segura en la clínica. Por tanto, nuestro objetivo era aportar evidencias preclínicas in vivo para estas investigaciones, modelando el escenario LDE en nuevos modelos animales y demostrando que la combinación de inhibidores específicos de BCL2 o MYC con anti-CD20 puede mejorar la supervivencia a largo plazo en modelos animales de LDCBG-LDE. Para ello, primero generamos y caracterizamos tres modelos murinos transgénicos que recapitulan la compleja progresión y el microambiente tumoral característico del LDCBGDEL en ratón, replicando las clásicas alteraciones genéticas de estos pacientes mediante mutaciones condicionales que ocurren en etapas tempranas de la reacción de centro germinal. Además, demostramos que la transformación maligna de las células B de centro germinal dirigida por la expresión de NF-κB promueve la rápida co-expresión de BCL2 y MYC y reprime la apoptosis, acumulando inestabilidad genómica y sensibilizando a las células tumorales a la inhibición de BCL2 (con venetoclax) o de MYC (con MYCi975). Además, contribuimos con evidencias in vivo de que la combinación de venetoclax con inmunoterapia dirigida contra CD20 puede promover efectos sinérgicos contra las células tumorales del linfoma, mejorando la supervivencia de los ratones. No solo demostramos que esta sinergia incrementa la muerte de las células tumorales doble-expresantes de BCL2 y MYC en respuesta al tratamiento combinatorio, sino que también demostramos, por primera vez en LDCBG, que venetoclax promueve el enriquecimiento de las células T CD8+ efectoras activadas que infiltran el tumor, ejerciendo por tanto un papel inmunomodulador en el microambiente tumoral del LDCBG doble-expresante. También, demostramos que se acelera la linfomagénesis mediante la expresión forzada de MYC desde etapas tempranas de la reacción del centro germinal. Sin embargo, esta linfomagénesis estaba acompañada por la aparición de tumores gastrointestinales no derivados de células B, posiblemente debido a una activación inespecífica de la expresión de MYC, y que, por tanto, no responden a la inmunoterapia convencional anti-CD20 ni a un tratamiento antibiótico, empeorando por tanto la supervivencia de los ratones. En conjunto, nuestros resultados aportan tanto una prueba de concepto preclínica como una justificación de que incorporar venetoclax a los tratamientos basados en inmunoterapia frente a CD20 puede mejorar la respuesta en estos pacientes con LDCBGLDE. Además, aportamos nuevas evidencias para testar combinaciones con inhibidores de MYC, ya sea incorporándolos al tratamiento estándar actual R-CHOP o combinándolos con inhibidores específicos de BCL2, atacando así simultáneamente ambos talones de Aquiles del tumor. Estos ensayos preclínicos se pueden hacer tanto en nuestros modelos preclínicos como en la novedosa técnica de cultivo 3D que hemos implementado, que permite el cultivo a largo plazo de las células tumorales con su microambiente tumoral en forma de esferoides, pudiendo así hacer un cribado de nuevas estrategias terapéuticas ex vivo. 2023-12-14T10:50:18Z 2023-12-14T10:50:18Z 2023-12-14 2023-06-21 info:eu-repo/semantics/doctoralThesis https://hdl.handle.net/10171/68058 eng info:eu-repo/semantics/openAccess application/pdf Universidad de Navarra |
| spellingShingle | Materias Investigacion::Ciencias de la Salud::Genética Diffuse large B cell lymphoma BCL2 MYC B-Cell lymphomagenesis Linfoma difuso de células B Sánchez, J. (Javier) Martinez-Climent, J.A. (José Ángel) Roa, S. (Sergio) Studying the role of BCL2 and MYC in the pathogenesis of diffuse large B cell lymphoma |
| title | Studying the role of BCL2 and MYC in the pathogenesis of diffuse large B cell lymphoma |
| title_full | Studying the role of BCL2 and MYC in the pathogenesis of diffuse large B cell lymphoma |
| title_fullStr | Studying the role of BCL2 and MYC in the pathogenesis of diffuse large B cell lymphoma |
| title_full_unstemmed | Studying the role of BCL2 and MYC in the pathogenesis of diffuse large B cell lymphoma |
| title_short | Studying the role of BCL2 and MYC in the pathogenesis of diffuse large B cell lymphoma |
| title_sort | studying the role of bcl2 and myc in the pathogenesis of diffuse large b cell lymphoma |
| topic | Materias Investigacion::Ciencias de la Salud::Genética Diffuse large B cell lymphoma BCL2 MYC B-Cell lymphomagenesis Linfoma difuso de células B |
| url | https://hdl.handle.net/10171/68058 |
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