RESUMEN
Despite the revolution of immunotherapy in cancer treatment, patients eventually progress due to the emergence of resistance. In this scenario, the selection of the tumor antigen can be decisive in the success of the clinical response. T cell bispecific antibodies (TCBs) are engineered molecules that include binding sites to the T cell receptor and to a tumor antigen. Using gastric CEA+/HER2+ MKN45 cells and TCBs directed against CEA or HER2, we show that the mechanism of resistance to a TCB is dependent on the tumor antigen. Acquired resistant models to a high-affinity-CEA-targeted TCB exhibit a reduction of CEA levels due to transcriptional silencing, which is reversible upon 5-AZA treatment. In contrast, a HER2-TCB resistant model maintains HER2 levels and exhibit a disruption of the interferon-gamma signaling. These results will help in the design of combinatorial strategies to increase the efficacy of cancer immunotherapies and to anticipate and overcome resistances.
Asunto(s)
Anticuerpos Biespecíficos , Humanos , Anticuerpos Biespecíficos/uso terapéutico , Antígeno Carcinoembrionario , Interferón gamma/metabolismo , Receptores de Antígenos de Linfocitos T/metabolismo , Linfocitos T , Línea Celular TumoralRESUMEN
Immunotherapy has raised high expectations in the treatment of virtually every cancer. Many current efforts are focused on ensuring the efficient delivery of active cytotoxic cells to tumors. It is assumed that, once these active cytotoxic cells are correctly engaged to cancer cells, they will unfailingly eliminate the latter, provided that inhibitory factors are in check. T cell bispecific antibodies (TCBs) and chimeric antigen receptors (CARs) offer an opportunity to test this assumption. Using TCB and CARs directed against HER2, here we show that disruption of interferon-gamma signaling confers resistance to killing by active T lymphocytes. The kinase JAK2, which transduces the signal initiated by interferon-gamma, is a component repeatedly disrupted in several independently generated resistant models. Our results unveil a seemingly widespread strategy used by cancer cells to resist clearance by redirected lymphocytes. In addition, they open the possibility that long-term inhibition of interferon-gamma signaling may impair the elimination phase of immunoediting and, thus, promote tumor progression.
Asunto(s)
Anticuerpos Biespecíficos/inmunología , Regulación hacia Abajo , Resistencia a Antineoplásicos/inmunología , Janus Quinasa 2/metabolismo , Neoplasias/inmunología , Receptor ErbB-2/metabolismo , Receptores Quiméricos de Antígenos/inmunología , Linfocitos T/inmunología , Animales , Línea Celular , Citotoxicidad Inmunológica , Humanos , Interferón gamma/metabolismo , Ratones , Transducción de Señal , Transcriptoma/genéticaRESUMEN
T cell bispecific antibodies (TCBs) are engineered molecules that include, within a single entity, binding sites to the T cell receptor and to tumor-associated or tumor-specific antigens. The receptor tyrosine kinase HER2 is a tumor-associated antigen in ~25% of breast cancers. TCBs targeting HER2 may result in severe toxicities, likely due to the expression of HER2 in normal epithelia. About 40% of HER2-positive tumors express p95HER2, a carboxyl-terminal fragment of HER2. Using specific antibodies, here, we show that p95HER2 is not expressed in normal tissues. We describe the development of p95HER2-TCB and show that it has a potent antitumor effect on p95HER2-expressing breast primary cancers and brain lesions. In contrast with a TCB targeting HER2, p95HER2-TCB has no effect on nontransformed cells that do not overexpress HER2. These data pave the way for the safe treatment of a subgroup of HER2-positive tumors by targeting a tumor-specific antigen.