Cáncer de mama HER2+: mecanismos de resistencia a tratamientos dirigidos y nuevas dianas terapéuticas

[ES]La tirosina quinasa transmembrana HER2 es importante en la homeostasis humana y su desregulación se ha relacionado con ciertos tipos de cáncer, como el cáncer de mama, en el que el 15-20% sobreexpresa HER2. Estos tumores tienden a crecer y diseminarse más rápido que otros cánceres de mama, pero es mucho más probable que respondan al tratamiento dirigido contra HER2. De hecho, las terapias anti-HER2 han demostrado ser muy eficaces y han aumentado las tasas de supervivencia de los pacientes con cáncer de mama HER2+ en los últimos 20 años. A pesar de la impresionante eficacia clínica observada, la resistencia primaria y secundaria a dichos fármacos ha surgido como un problema clínico. Aunque se han descrito diferentes mecanismos de resistencias a terapias dirigidas contra HER2, la incidencia de resistencias a tratamientos anti-HER2 es significativamente mayor que la frecuencia de presentación de las anomalías moleculares descritas, lo cual indica que deben existir mecanismos alternativos de resistencia. Considerando lo anterior, nos planteamos el objetivo de identificar nuevas dianas terapéuticas en cáncer de mama HER2+ y su aplicabilidad en el escenario de resistencia a terapias anti-HER2

JKST6, a novel multikinase modulator of the BCR-ABL1/STAT5 signaling pathway that potentiates direct BCR-ABL1 inhibition and overcomes imatinib resistance in chronic myelogenous leukemia

Chronic myelogenous leukemia (CML) is a hematological malignancy that highly depends on the BCR-ABL1/STAT5 signaling pathway for cell survival. First-line treatments for CML consist of tyrosine kinase inhibitors that efficiently target BCR-ABL1 activity. However, drug resistance and intolerance are still therapeutic limitations in Ph+ cells. Therefore, the development of new anti-CML drugs that exhibit alternative mechanisms to overcome these limitations is a desirable goal. In this work, the antitumoral activity of JKST6, a naphthoquinone-pyrone hybrid, was assessed in imatinib-sensitive and imatinib-resistant human CML cells. Live-cell imaging analysis revealed JKST6 potent antiproliferative activity in 2D and 3D CML cultures. JKST6 provoked cell increase in the subG1 phase along with a reduction in the G0/G1 phase and altered the expression of key proteins involved in the control of mitosis and DNA damage. Rapid increases in Annexin V staining and activation/cleavage of caspases 8, 9 and 3 were observed after JKST6 treatment in CML cells. Of interest, JKST6 inhibited BCR-ABL1/STAT5 signaling through oncokinase downregulation that was preceded by rapid polyubiquitination. In addition, JKST6 caused a transient increase in JNK and AKT phosphorylation, whereas the phosphorylation of P38-MAPK and Src was reduced. Combinatory treatment unveiled synergistic effects between imatinib and JKST6. Notably, JKST6 maintained its antitumor efficacy in BCR-ABL1-T315I-positive cells and CML cells that overexpress BCR-ABL and even restored imatinib efficacy after a short exposure time. These findings, together with the observed low toxicity of JKST6, reveal a novel multikinase modulator that might overcome the limitations of BCR-ABL1 inhibitors in CML therapy.This research has been funded by Spanish Ministry of Economy and Competitiveness - MINECO - (SAF 2015–65113-C2–1-R and RTI2018–094356-B-C21 to AEB, SAF2015–65113-C2–2 to LFP, SAF2017–88026-R to JL) with the co-funding of European Regional Development Fund (EU-ERDF), Canary Islands Government (CEI2018–23/ACIISI to BG, CEI2019–08/ACIISI to BG and LFP, ProID2021010037 to AEB, LFP and BG) and "Juan de la Cierva Incorporacion" Grant Program from the Ministry of Science, Innovation and Universities (IJC2018-035193-I to CR). This project has been also supported by Alfredo Martin-Reyes Foundation (Arehucas)-Canary Islands Foundation for Cancer Research (FICIC). HAT is recipient of a predoctoral program grant from ULPGC (2016). JCM was funded by the Instituto de Salud Carlos III through a Miguel Servet program (CPII17/ 00015)

An anti-EGFR antibody-drug conjugate overcomes resistance to HER2-targeted drugs

Trastuzumab-emtansine (T-DM1) is an antibody-drug conjugate (ADC) that was approved in 2013 to treat HER2+ breast cancer. Despite its efficacy in the clinic, some patients exhibit intrinsic or acquired resistance to such ADC. To characterize mechanisms of resistance to T-DM1, we isolated several HER2+ resistant clones derived from the HCC1954 HER2+ cell line. The isolated clones were different as per their transcriptomic profiles. However, all the T-DM1-resistant clones showed decreased HER2 levels. Yet, the clones were still oncogenically dependent on HER2, as indicated by knock down experiments. The decrease in HER2 expression caused acquired resistance to T-DM1 and to other anti-HER2 therapies. Antibody array analyses showed that the epidermal growth factor receptor (EGFR) was expressed in these T-DM1-resistant HCC1954 clones. Indeed, therapies targeting EGFR, particularly cetuximab-DM1, demonstrated a strong anti-proliferative action on cells with acquired resistance to T-DM1 and HER2 loss. The expression of EGFR in cells resistant to T-DM1 offers the possibility of using therapies directed to this receptor to combat resistance to anti-HER2 drugs and loss of HER2 overexpression.Ministry of Economy and Competitiveness of Spain (BFU2015-71371-R and PID2020-115605RB-I00), the Instituto de Salud Carlos III through CIBERONC, Junta de Castilla y León (CSI146P20), ALMOM, ACMUMA, UCCTA, the CRIS Cancer Foundation and the Regional Development Funding Program (FEDER) “A way to make Europe”. LGS was recipient of a predoctoral contract (BES-2016-077748); and is at present contracted by the Cancer Research Foundation of the Salamanca University (FICUS)

Generation of antibody‐drug conjugate resistant models

© 2021 by the authors.In the last 20 years, antibody-drug conjugates (ADCs) have been incorporated into the oncology clinic as treatments for several types of cancer. So far, the Food and Drug Administration (FDA) has approved 11 ADCs and other ADCs are in the late stages of clinical development. Despite the efficacy of this type of drug, the tumors of some patients may result in resistance to ADCs. Due to this, it is essential not only to comprehend resistance mechanisms but also to develop strategies to overcome resistance to ADCs. To reach these goals, the generation and use of preclinical models to study those mechanisms of resistance are critical. Some cells or patient tumors may result in primary resistance to the action of an ADC, even if they express the antigen against which the ADC is directed. Isolated primary tumoral cells, cell lines, or patient explants (patient-derived xenografts) with these characteristics can be used to study primary resistance. The most common method to generate models of secondary resistance is to treat cancer cell lines or tumors with an ADC. Two strategies, either continuous treatment with the ADC or intermittent treatment, have successfully been used to develop those resistance models.AP: Ministry of Economy and Competitiveness of Spain (BFU2015-71371-R), the Instituto de Salud Carlos III through CIBERONC, Junta de Castilla y León (CSI146P20), ALMOM, ACMUMA, UCCTA and the CRIS Cancer Foundation. AO: Instituto de Salud Carlos III (PI19/00808), ACEPAIN, and CRIS Cancer Foundation. Work carried out in AP and AO laboratories receives support from the European Community through the Regional Development Funding Program (FEDER). LGS was recipient of a predoctoral contract (BES-2016-077748); and is at present contracted by the Cancer Research Foundation of the Salamanca University (FICUS)

Novel adcs and strategies to overcome resistance to anti-her2 adcs

During recent years, a number of new compounds against HER2 have reached clinics, improving the prognosis and quality of life of HER2-positive breast cancer patients. Nonetheless, resistance to standard-of-care drugs has motivated the development of novel agents, such as new antibody-drug conjugates (ADCs). The latter are a group of drugs that benefit from the potency of cytotoxic agents whose action is specifically guided to the tumor by the target-specific antibody. Two anti-HER2 ADCs have reached the clinic: trastuzumab-emtansine and, more recently, trastuzumab-deruxtecan. In addition, several other HER2-targeted ADCs are in preclinical or clinical development, some of them with promising signs of activity. In the present review, the structure, mechanism of action, and potential resistance to all these ADCs will be described. Specific attention will be given to discussing novel strategies to circumvent resistance to ADCs.This work was supported by grants from the Ministry of Economy and Competitiveness of Spain (BFU2015-71371-R and PID2020-115605RB-I00), the Instituto de Salud Carlos III through CIBERONC, Junta de Castilla y León (CSI146P20), ALMOM, ACMUMA, UCCTA and the CRIS Cancer Foundation (A.P.), and by the Instituto de Salud Carlos III (PI19/00808), ACEPAIN, and CRIS Cancer Foundation (A.O.). Work carried out in A.P.’s and A.O.’s laboratories received support from the European Community through the Regional Development Funding Program (FEDER). L.G.-S. was the recipient of a predoctoral contract (BES-2016-077748) and is presently contracted with the Cancer Research Foundation of Salamanca University (FICUS)

HER3 targeting with an antibody‐drug conjugate bypasses resistance to anti‐HER2 therapies

Despite impressive clinical benefit obtained with anti‐HER2‐targeted therapies, in advances stages, especially in the metastatic setting, HER2‐positive tumors remain incurable. Therefore, it is important to develop novel strategies to fight these tumors, especially when they become resistant to available therapies. We show here that the anti‐HER3 antibody–drug conjugate EV20/MMAF exerted potent anti‐tumoral properties against several models of primary resistance and secondary resistance to common anti‐HER2 available therapies, including trastuzumab, lapatinib, neratinib, and trastuzumab‐emtansine. HER3 was expressed in these HER2+ breast cancer cells and knockdown experiments demonstrated that HER3 expression was required for the action of EV20/MMAF. In mice injected with trastuzumab‐resistant HER2+ cells, a single dose of EV20/MMAF caused complete and long‐lasting tumor regression. Mechanistically, EV20/MMAF bound to cell surface HER3 and became internalized to the lysosomes. Treatment with EV20/MMAF caused cell cycle arrest in mitosis and promoted cell death through mitotic catastrophe. These findings encourage the clinical testing of EV20/MMAF for several indications in the HER2+ cancer clinic, including situations in which HER2+ tumors become refractory to approved anti‐HER2 therapies.AP: Ministry of Economy and Competitiveness of Spain (BFU2015‐71371‐R), the Instituto de Salud Carlos III through the Spanish Cancer Centers Network Program (RD12/0036/0003) and CIBERONC, the Scientific Foundation of the Spanish Association Against Cancer (AECC), ALMOM, and the CRIS Cancer Foundation. Work carried out in AP and AO laboratories receives support from the European Community through the Regional Development Funding Program (FEDER). GS: Fondazione‐AIRC (IG GRANT 2016, Id 18467). EC is the recipient of an AIRC fellowship. LGS is recipient of a predoctoral contract (BES‐2016‐077748).Peer reviewe

Adaptive resistance to trastuzumab impairs response to neratinib and lapatinib through deregulation of cell death mechanisms

Small molecule inhibitors (TKIs) of HER2 have demonstrated clinical benefit in HER2-positive breast tumors. One of them, lapatinib, is used once advanced tumors become refractory to the HER2 antibody trastuzumab. Another one, neratinib, has shown benefit in high-risk early-stage breast cancer after trastuzumab-based therapies. A common characteristic is that patients are formerly treated with trastuzumab. We have explored whether trastuzumab previous therapy affects its antitumoral action. Long time exposure of the HER2+ cell line BT474 to trastuzumab resulted in trastuzumab-insensitive cells (BTRH cells). While treatment of wild type BT474 cells with lapatinib or neratinib resulted in decreased viability, BTRH cells were resistant to the action of these TKIs. Analogous results were obtained using trastuzumab-resistant cells derived from a PDX. Functional transcriptomic analyses and biochemical studies demonstrated that the TKIs caused DNA damage and apoptosis in wild type cells, but not in BTRH. Moreover, previous treatment with trastuzumab impairs response to small TKIs, by eliminating their proapoptotic action. Moreover, actioning on the apoptotic machinery using a chemical library of proapoptotic compounds led to the identification of clinical-stage drugs that may be used to fight trastuzumab-TKI resistance.Ministry of Economy and Competitiveness of Spain (BFU2015-71371-R), the Instituto de Salud Carlos III through the Spanish Cancer Centers Network Program (RD12/0036/0003) and CIBERONC, the Scientific Foundation of the Spanish Association Against Cancer (AECC), the CRIS Cancer Foundation, ALMOM, ACMUMA and UCCTA. The Cancer Research Institute and the work carried out in our laboratory receive support from the European Community through the Regional Development Funding Program (FEDER). LDG was supported by a predoctoral contract of the Consejería de Educación of the Castilla and León Autonomous Government. LGS was supported by a MINECO predoctoral fellowship (BES-2016-077748).Peer reviewe

Altered proTGFα/cleaved TGFα ratios offer new therapeutic strategies in renal carcinoma

© The Author(s).[Background]: Treatment of renal cancer has significantly improved with the arrival to the clinic of kinase inhibitors and immunotherapies. However, the disease is still incurable in advanced stages. The fact that several approved inhibitors for kidney cancer target receptor tyrosine kinases (RTKs) suggests that these proteins play a critical role in the pathophysiology of the disease. Based on these precedents, we decided to explore whether RTKs other than those targeted by approved drugs, contribute to the development of kidney cancer.[Methods]: The activation status of 49 RTKs in 44 paired samples of normal and tumor kidney tissue was explored using antibody arrays, with validation by western blotting. Genetic and pharmacologic approaches were followed to study the biological implications of targeting the epidermal growth factor receptor (EGFR) and its ligand Transforming Growth Factor-α (TGFα).[Results]: Activation of the EGFR was found in a substantial number of tumors. Moreover, kidney tumors expressed elevated levels of TGFα. Down-regulation of EGFR or TGFα using RNAi or their pharmacological targeting with blocking antibodies resulted in inhibition of the proliferation of in vitro cellular models of renal cancer. Importantly, differences in the molecular forms of TGFα expressed by tumors and normal tissues were found. In fact, tumor TGFα was membrane anchored, while that expressed by normal kidney tissue was proteolytically processed.[Conclusions]: The EGFR-TGFα axis plays a relevant role in the pathophysiology of kidney cancer. This study unveils a distinctive feature in renal cell carcinomas, which is the presence of membrane-anchored TGFα. That characteristic could be exploited therapeutically to act on tumors expressing transmembrane TGFα, for example, with antibody drug conjugates that could recognize the extracellular region of that protein.AP: Ministry of Economy and Competitiveness of Spain (BFU2015–71371-R), the Instituto de Salud Carlos III through CIBERONC, Junta de Castilla y León (CSI146P20), the Scientific Foundation of the Spanish Association Against Cancer (AECC), ALMOM, ACMUMA and the CRIS Cancer Foundation. JCM is funded by the Instituto de Salud Carlos III through a Miguel Servet program (CP12/03073 and CPII17/00015) and receives research support from the same institution (PI18/00796). LGS is recipient of a predoctoral contract (BES-2016-077748). IRP is recipient of a predoctoral contract (CSI030–18). SGA is recipient of a predoctoral contract from the MINECO (BES-2013-065223). Work carried out in our laboratory receives support from the European Community through the Regional Development Funding Program (FEDER)

Targeting trastuzumab and T-DM1 resistant breast cancer cells with EV20/MMAF, an Antibody-Drug Conjugated against HER-3

Trabajo presentado en AACR Annual Meeting, celebrado en Chicago (Estados Unidos) del 14 al 18 de abril de 2018