Blocking Myc to treat cancer : reflecting on two decades of Omomyc

First designed and published in 1998 as a laboratory tool to study Myc perturbation, Omomyc has come a long way in the past 22 years. This dominant negative has contributed to our understanding of Myc biology when expressed, first, in normal and cancer cells, and later in genetically-engineered mice, and has shown remarkable anti-cancer properties in a wide range of tumor types. The recently described therapeutic effect of purified Omomyc mini-protein-following the surprising discovery of its cell-penetrating capacity-constitutes a paradigm shift. Now, much more than a proof of concept, the most characterized Myc inhibitor to date is advancing in its drug development pipeline, pushing Myc inhibition into the clinic

Pharmacokinetic Analysis of Omomyc Shows Lasting Structural Integrity and Long Terminal Half-Life in Tumor Tissue

Omomyc; Mass spectrometry; Protein therapeuticsOmomyc; Espectrometría de masas; Terapéutica de proteínasOmomyc; Espectrometria de masses; Terapèutica de proteïnesMYC is an oncoprotein causally involved in the majority of human cancers and a most wanted target for cancer treatment. Omomyc is the best-characterized MYC dominant negative to date. In the last years, it has been developed into a therapeutic miniprotein for solid tumor treatment and recently reached clinical stage. However, since the in vivo stability of therapeutic proteins, especially within the tumor vicinity, can be affected by proteolytic degradation, the perception of Omomyc as a valid therapeutic agent has been often questioned. In this study, we used a mass spectrometry approach to evaluate the stability of Omomyc in tumor biopsies from murine xenografts following its intravenous administration. Our data strongly support that the integrity of the functional domains of Omomyc (DNA binding and dimerization region) remains preserved in the tumor tissue for at least 72 hours following administration and that the protein shows superior pharmacokinetics in the tumor compartment compared with blood serum.This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 872212 and from the Ministerio de Ciencia e Innovacion under grant no. RTC2019-007067-1

Ibrutinib repurposing : from B-cell malignancies to solid tumors

Ibrutinib (Imbruvica®, also known as PCI-32765) is a first-in-class, irreversible small-molecule inhibitorof Bruton's Tyrosine Kinase (BTK) that binds covalently to cysteine C481 within the ATP-binding pocket. Since BTK is a Tec family non-receptor tyrosine kinase that is specifically required for B-cell antigen receptor (BCR) signaling, ibrutinib was initially developed for the treatment of B-cell malignancies. Currently, it is approved for first-line treatment of chronic lymphocytic leukemia, and for the treatment of mantle-cell lymphoma and Waldenström's macroglobulinemia patients that have received at least one previous therapy

BET inhibition is an effective approach against KRAS-driven PDAC and NSCLC

Effectively treating KRAS-driven tumors remains an unsolved challenge. The inhibition of downstream signaling effectors is a way of overcoming the issue of direct targeting of mutant KRAS, which has shown limited efficacy so far. Bromodomain and Extra-Terminal (BET) protein inhibition has displayed anti-tumor activity in a wide range of cancers, including KRAS-driven malignancies. Here, we preclinically evaluate the effect of BET inhibition making use of a new BET inhibitor, BAY 1238097, against Pancreatic Ductal Adenocarcinoma (PDAC) and Non-Small Cell Lung Cancer (NSCLC) models harboring RAS mutations both in vivo and in vitro. Our results demonstrate that BET inhibition displays significant therapeutic impact in genetic mouse models of KRAS-driven PDAC and NSCLC, reducing both tumor area and tumor grade. The same approach also causes a significant reduction in cell number of a panel of RAS-mutated human cancer cell lines (8 PDAC and 6 NSCLC). In this context, we demonstrate that while BET inhibition by BAY 1238097 decreases MYC expression in some cell lines, at least in PDAC cells its anti-tumorigenic effect is independent of MYC regulation. Together, these studies reinforce the use of BET inhibition and prompt the optimization of more efficient and less toxic BET inhibitors for the treatment of KRAS-driven malignancies, which are in urgent therapeutic need

Reducing MYC's transcriptional footprint unveils a good prognostic gene signature in melanoma

MYC; Omomyc; MelanomaMYC; Omomyc; MelanomaMYC; Omomyc; MelanomaMYC's key role in oncogenesis and tumor progression has long been established for most human cancers. In melanoma, its deregulated activity by amplification of 8q24 chromosome or by upstream signaling coming from activating mutations in the RAS/RAF/MAPK pathway—the most predominantly mutated pathway in this disease—turns MYC into not only a driver but also a facilitator of melanoma progression, with documented effects leading to an aggressive clinical course and resistance to targeted therapy. Here, by making use of Omomyc, the most characterized MYC inhibitor to date that has just successfully completed a phase I clinical trial, we show for the first time that MYC inhibition in melanoma induces remarkable transcriptional modulation, resulting in severely compromised tumor growth and a clear abrogation of metastatic capacity independently of the driver mutation. By reducing MYC's transcriptional footprint in melanoma, Omomyc elicits gene expression profiles remarkably similar to those of patients with good prognosis, underlining the therapeutic potential that such an approach could eventually have in the clinic in this dismal disease.M.F.Z.-F. was supported by the Juan de la Cierva Programme of the Spanish Ministry of Economy and Competitiveness (IJCI-2014-22403) and Fundació La Marató de TV3 (grant 474/C/2019); F.G. was supported by Spanish Ministry of Science and Innovation Contratos Predoctorales de Formación en Investigación en Salud (PFIS; FI20/00274); I.G.-L. was supported by a grant from the University Teacher Training Program (FPU), Ministry of Universities (FPU20/04812); and S.M.-M. was supported by the Generalitat de Catalunya “Contractació de Personal Investigador Novell (FI-DGR)” 2016 fellowship (2016FI_B 00592). This project was funded by grants from the Spanish Ministry of Science and Innovation (Fondo de Inversión en Salud [FIS] PI19/01277, which also supported I.G.-L. and S.M.-M, and Retos-Colaboración 2019 RTC2019-007067-1), La Marató TV3, the Generalitat de Catalunya AGAUR 2017 grant SGR-3193, and the European Research Council (ERC-PoC II/3079/SYST-iMYC [813132]). We thank the rest of the Soucek laboratory for critical reading of the manuscript, and the personnel at Vall d'Hebron Research Institute (VHIR) High Technology Unit. We acknowledge Vall d'Hebron Institute of Oncology and the Cellex Foundation for providing research facilities and equipment

Myc inhibition is effective against glioma and reveals a role for Myc in proficient mitosis.

Gliomas are the most common primary tumours affecting the adult central nervous system and respond poorly to standard therapy. Myc is causally implicated in most human tumours and the majority of glioblastomas have elevated Myc levels. Using the Myc dominant negative Omomyc, we previously showed that Myc inhibition is a promising strategy for cancer therapy. Here, we preclinically validate Myc inhibition as a therapeutic strategy in mouse and human glioma, using a mouse model of spontaneous multifocal invasive astrocytoma and its derived neuroprogenitors, human glioblastoma cell lines, and patient-derived tumours both in vitro and in orthotopic xenografts. Across all these experimental models we find that Myc inhibition reduces proliferation, increases apoptosis and remarkably, elicits the formation of multinucleated cells that then arrest or die by mitotic catastrophe, revealing a new role for Myc in the proficient division of glioma cells

The Wnt signaling receptor Fzd9 is essential for Myc-driven tumorigenesis in pancreatic islets

Zacarías-Fluck, et al identify and validate the Wnt receptor Fzd9 as a key effector of Myc-Wnt signaling cross-talk in a mouse model of Myc-driven pancreatic insulinomas. The huge cadre of genes regulated by Myc has obstructed the identification of critical effectors that are essential for Myc-driven tumorigenesis. Here, we describe how only the lack of the receptor Fzd9, previously identified as a Myc transcriptional target, impairs sustained tumor expansion and β-cell dedifferentiation in a mouse model of Myc-driven insulinoma, allows pancreatic islets to maintain their physiological structure and affects Myc-related global gene expression. Importantly, Wnt signaling inhibition in Fzd9-competent mice largely recapitulates the suppression of proliferation caused by Fzd9 deficiency upon Myc activation. Together, our results indicate that the Wnt signaling receptor Fzd9 is essential for Myc-induced tumorigenesis in pancreatic islets

Inhibiting Myc and the Myc dependent inflammatory response as cancer therapies

Aquesta tesi s’ha realitzat al Laboratori de Modelització de Teràpies Anti-tumorals en Ratolí dirigit per la Dra. Laura Soucek al Programa de Recerca Preclínica del Vall d’Hebron Institut d’Oncologia (VHIO), i comprèn dos projectes diferenciats centrats en dues de les funcions oncogèniques de Myc. Pel que fa al primer projecte, hem validat farmacològicament la inhibició dels mastòcits com a estratègia terapèutica contra l’adenocarcinoma ductal de pàncrees (PDAC). Per a fer-ho, hem utilitzat ibrutinib, un inhibidor de la tirosina quinasa de Bruton (BTK) en models de ratolí de PDAC, el tumor de pàncrees més comú i agressiu. El tractament amb ibrutinib inhibeix la desgranulació dels mastòcits, redueix la proliferació i la infiltració leucocitària a l’estroma del tumor i redueix dràsticament la deposició de col·lagen. En models de PDAC fibrosos, tant transgènics com derivats de pacients, ibrutinib allarga la supervivència i és sinèrgic amb la quimioteràpia, demostrant l’aplicabilitat clínica d’aquest fàrmac enfront del càncer de pàncrees. Aquest projecte a portat a la publicació d’un article científic i un editorial (Masso-Valles et al. 2015; Masso-Valles et al. 2016), a més de contribuir a la posada en marxa d’assajos clínics per testar la combinació d’ibrutinib i quimioteràpia en pacients amb PDAC metastàtic (fase 1/2: NCT02562898 i fase 2/3: NCT02436668). El segon projecte està centrat en la relació entre Myc i la metàstasi. Hem estudiat el potencial d’Omomyc, un mutant dominant negatiu de Myc que ha demostrat una eficàcia extraordinària enfront a tumors primaris en diversos models de ratolí, contra el càncer de mama metastàtic. Hem demostrat que la inhibició de Myc mitjançant Omomyc és una teràpia segura i eficaç contra el càncer de mama, impedint la proliferació cel·lular, l’angiogènesi, la migració i la invasió in vitro, reduint dramàticament el creixement dels tumors primaris i les metàstasis en ratolins immunodeprimits, fins i tot erradicant metàstasis establertes, i impedint gairebé completament la formació de tumors primaris i metàstasis en ratolins immunocompetents. D’aquesta manera, hem demostrat per primera vegada l’aplicabilitat d’Omomyc enfront de les metàstasis, en contra de la noció preestablerta que la inhibició de Myc podria potenciar, enlloc d’inhibir, el procés d’invasió. Finalment, hem validat TMTP1-Omomyc com el primer fàrmac basat en Omomyc administrable directament per al tractament del càncer de mama metastàtic triple negatiu, proporcionant una nova oportunitat terapèutica per als pacients que pateixen aquesta malaltia devastadora i incurable.The work of this thesis was carried out in the Mouse Models of Cancer Therapies Laboratory led by Dr. Laura Soucek in the Preclinical Research Program of the Vall d’Hebron Institute of Oncology (VHIO), and comprises two differentiated parts centered on two oncogenic functions of Myc. In the first project we validated the pharmacological inhibition of mast cells as a therapeutic strategy against pancreatic ductal adenocarcinoma (PDAC). To do so, we made use of the Bruton’s tyrosine kinase (BTK) inhibitor ibrutinib in mouse models of PDAC, the most common and aggressive pancreatic tumor. Treatment with ibrutinib inhibited mast cell degranulation, reduced cell proliferation and leukocytic infiltration in the tumor stroma and dramatically reduced collagen deposition. In fibrotic mouse models of PDAC, both genetically-engineered and patient-derived, ibrutinib extended survival and synergized with chemotherapy, demonstrating the clinical applicability of this drug against pancreatic cancer. This project has led to the publication of a research paper and an editorial (Masso-Valles et al. 2015; Masso-Valles et al. 2016), as well as contributing to the initiation of clinical trials combining ibrutinib with chemotherapy in patients with metastatic PDAC (phase 1/2: NCT02562898 and phase 2/3: NCT02436668). The second project is focused on the relationship between Myc and metastasis. We studied de potential of Omomyc, a Myc dominant negative mutant that had shown extraordinary efficacy against primary tumors in multiple mouse models, against metastatic breast cancer. We demonstrated that Myc inhibition by Omomyc is a safe and effective therapy against breast cancer by impairing cell proliferation, angiogenesis, migration and invasion in vitro, dramatically reducing primary tumor and metastatic growth in immunocompromised mice, even eradicating established metastases, and preventing primary tumor and metastatic formation almost completely in immunocompetent mice. Thus, we have demonstrated for the first time the applicability of Omomyc against metastasis, challenging the pre-established notion that Myc inhibition could potentiate, rather than inhibit, invasion. Finally, we have validated TMTP1-Omomyc as the first direct-deliverable Omomyc-based drug for the treatment of metastatic triple negative breast cancer, providing a new therapeutic opportunity for patients suffering from this dreadful and incurable disease

Inhibiting Myc and the Myc dependent inflammatory response as cancer therapies

Premi Extraordinari de Doctorat concedit pels programes de doctorat de la UAB per curs acadèmic 2016-2017Aquesta tesi s'ha realitzat al Laboratori de Modelització de Teràpies Anti-tumorals en Ratolí dirigit per la Dra. Laura Soucek al Programa de Recerca Preclínica del Vall d'Hebron Institut d'Oncologia (VHIO), i comprèn dos projectes diferenciats centrats en dues de les funcions oncogèniques de Myc. Pel que fa al primer projecte, hem validat farmacològicament la inhibició dels mastòcits com a estratègia terapèutica contra l'adenocarcinoma ductal de pàncrees (PDAC). Per a fer-ho, hem utilitzat ibrutinib, un inhibidor de la tirosina quinasa de Bruton (BTK) en models de ratolí de PDAC, el tumor de pàncrees més comú i agressiu. El tractament amb ibrutinib inhibeix la desgranulació dels mastòcits, redueix la proliferació i la infiltració leucocitària a l'estroma del tumor i redueix dràsticament la deposició de col·lagen. En models de PDAC fibrosos, tant transgènics com derivats de pacients, ibrutinib allarga la supervivència i és sinèrgic amb la quimioteràpia, demostrant l'aplicabilitat clínica d'aquest fàrmac enfront del càncer de pàncrees. Aquest projecte a portat a la publicació d'un article científic i un editorial (Masso-Valles et al. 2015; Masso-Valles et al. 2016), a més de contribuir a la posada en marxa d'assajos clínics per testar la combinació d'ibrutinib i quimioteràpia en pacients amb PDAC metastàtic (fase 1/2: NCT02562898 i fase 2/3: NCT02436668). El segon projecte està centrat en la relació entre Myc i la metàstasi. Hem estudiat el potencial d'Omomyc, un mutant dominant negatiu de Myc que ha demostrat una eficàcia extraordinària enfront a tumors primaris en diversos models de ratolí, contra el càncer de mama metastàtic. Hem demostrat que la inhibició de Myc mitjançant Omomyc és una teràpia segura i eficaç contra el càncer de mama, impedint la proliferació cel·lular, l'angiogènesi, la migració i la invasió in vitro, reduint dramàticament el creixement dels tumors primaris i les metàstasis en ratolins immunodeprimits, fins i tot erradicant metàstasis establertes, i impedint gairebé completament la formació de tumors primaris i metàstasis en ratolins immunocompetents. D'aquesta manera, hem demostrat per primera vegada l'aplicabilitat d'Omomyc enfront de les metàstasis, en contra de la noció preestablerta que la inhibició de Myc podria potenciar, enlloc d'inhibir, el procés d'invasió. Finalment, hem validat TMTP1-Omomyc com el primer fàrmac basat en Omomyc administrable directament per al tractament del càncer de mama metastàtic triple negatiu, proporcionant una nova oportunitat terapèutica per als pacients que pateixen aquesta malaltia devastadora i incurable.The work of this thesis was carried out in the Mouse Models of Cancer Therapies Laboratory led by Dr. Laura Soucek in the Preclinical Research Program of the Vall d'Hebron Institute of Oncology (VHIO), and comprises two differentiated parts centered on two oncogenic functions of Myc. In the first project we validated the pharmacological inhibition of mast cells as a therapeutic strategy against pancreatic ductal adenocarcinoma (PDAC). To do so, we made use of the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib in mouse models of PDAC, the most common and aggressive pancreatic tumor. Treatment with ibrutinib inhibited mast cell degranulation, reduced cell proliferation and leukocytic infiltration in the tumor stroma and dramatically reduced collagen deposition. In fibrotic mouse models of PDAC, both genetically-engineered and patient-derived, ibrutinib extended survival and synergized with chemotherapy, demonstrating the clinical applicability of this drug against pancreatic cancer. This project has led to the publication of a research paper and an editorial (Masso-Valles et al. 2015; Masso-Valles et al. 2016), as well as contributing to the initiation of clinical trials combining ibrutinib with chemotherapy in patients with metastatic PDAC (phase 1/2: NCT02562898 and phase 2/3: NCT02436668). The second project is focused on the relationship between Myc and metastasis. We studied de potential of Omomyc, a Myc dominant negative mutant that had shown extraordinary efficacy against primary tumors in multiple mouse models, against metastatic breast cancer. We demonstrated that Myc inhibition by Omomyc is a safe and effective therapy against breast cancer by impairing cell proliferation, angiogenesis, migration and invasion in vitro, dramatically reducing primary tumor and metastatic growth in immunocompromised mice, even eradicating established metastases, and preventing primary tumor and metastatic formation almost completely in immunocompetent mice. Thus, we have demonstrated for the first time the applicability of Omomyc against metastasis, challenging the pre-established notion that Myc inhibition could potentiate, rather than inhibit, invasion. Finally, we have validated TMTP1-Omomyc as the first direct-deliverable Omomyc-based drug for the treatment of metastatic triple negative breast cancer, providing a new therapeutic opportunity for patients suffering from this dreadful and incurable disease

Ibrutinib repurposing : from B-cell malignancies to solid tumors

Ibrutinib (Imbruvica®, also known as PCI-32765) is a first-in-class, irreversible small-molecule inhibitorof Bruton's Tyrosine Kinase (BTK) that binds covalently to cysteine C481 within the ATP-binding pocket. Since BTK is a Tec family non-receptor tyrosine kinase that is specifically required for B-cell antigen receptor (BCR) signaling, ibrutinib was initially developed for the treatment of B-cell malignancies. Currently, it is approved for first-line treatment of chronic lymphocytic leukemia, and for the treatment of mantle-cell lymphoma and Waldenström's macroglobulinemia patients that have received at least one previous therapy