Biology subjects

Mielgo, A.

Publications and source records attributed to Mielgo, A..

4 recordsLinked to original sources

bioRxiv2019

Blockade of stromal Gas6 alters cancer cell plasticity, activates NK cells and inhibits pancreatic cancer metastasis.

Pancreatic ductal adenocarcinoma (PDA) is one of the deadliest cancers due to its aggressive and metastatic nature. PDA is characterized by a rich tumor stroma with abundant macrophages, fibroblasts and collagen deposition that can represent up to 90% of the tumor mass. Activation of the tyrosine kinase receptor AXL and expression of its ligand growth arrest-specific protein 6 (Gas6) correlate with a poor prognosis and increased metastasis in pancreatic cancer patients. Gas6 is a multifunctional protein that can be secreted by several cell types and regulates multiple processes, including cancer cell plasticity, angiogenesis and immune cell functions. However, the role of Gas6 in pancreatic cancer metastasis has not been fully investigated. In these studies we find that, in pancreatic tumors, Gas6 is mainly produced by tumor associated macrophages (TAMs) and cancer associated fibroblasts (CAFs) and that pharmacological blockade of Gas6 partially reverses epithelial-to-mesenchymal transition (EMT) of tumor cells and supports NK cell activation, thereby inhibiting pancreatic cancer metastasis. Our data suggest that Gas6 simultaneously acts on both the tumor cells and the NK cells to support pancreatic cancer metastasis. This study supports the rationale for targeting Gas6 in pancreatic cancer and use NK cells as a potential biomarker for response to anti-Gas6 therapy.

cancer biology↗

bioRxiv2018

Interfering with MIF-CD74 signalling on macrophages and dendritic cells with a peptide-based approach restores the immune response against metastatic melanoma.

Mounting an effective immune response against cancer requires the activation of innate and adaptive immune cells. Metastatic melanoma is the most aggressive form of skin cancer. Immunotherapies that boost the activity of effector T cells have shown a remarkable success in melanoma treatment. Patients, however, can develop resistance to such therapies by mechanisms that include the establishment of an immune suppressive tumour microenvironment. Understanding how metastatic melanoma cells suppress the immune system is vital to develop effective immunotherapies against this disease. In this study, we find that the innate immune cells, macrophages and dendritic cells are suppressed in metastatic melanoma. The Ig-CDR-based peptide C36L1 is able to restore macrophages and dendritic cells immunogenic functions and to inhibit metastatic growth in vivo. Mechanistically, we found that C36L1 interferes with the MIF-CD74 tumour-innate immune cells immunosuppressive signalling pathway and thereby restores an effective anti-tumour immune response. C36L1 directly binds to CD74 on macrophages and dendritic cells, disturbing CD74 structural dynamics and inhibiting MIF signalling through CD74. Our findings suggest that interfering with MIF-CD74 immunosuppressive signalling in macrophages and dendritic cells using peptide-based immunotherapy can restore the anti-tumour immune response in metastatic melanoma. Our study provides the rationale for further development of peptide-based therapies to restore the anti-tumour immune response.

cancer biology↗

bioRxiv2017

Macrophage-derived granulin drives resistance to immune checkpoint inhibition in metastatic pancreatic cancer

The ability of disseminated cancer cells to evade the immune response is a critical step for efficient metastatic progression. Protection against an immune attack is often provided by the tumour microenvironment that suppresses and/or excludes cytotoxic CD8+ T cells. Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive metastatic disease with unmet needs, yet the immuno-protective role of the metastatic tumour microenvironment in pancreatic cancer is not completely understood. In this study we find that macrophage-derived granulin contributes to cytotoxic CD8+ T cell exclusion in metastatic livers. Mechanistically, we find that granulin expression by macrophages is induced in response to colony stimulating factor-1. Genetic depletion of granulin reduces the formation a fibrotic stroma, thereby allowing T cell entry at the metastatic site. While metastatic PDAC tumours are largely resistant to anti-PD-1 therapy, blockade of PD-1 in granulin depleted tumours restored the anti-tumour immune defence and dramatically decreased metastatic tumour burden. These findings suggest that targeting granulin may serve as a potential therapeutic strategy to restore CD8+ T cell infiltration in metastatic PDAC, thereby converting PDAC metastatic tumours, which are refractory to immune checkpoint inhibitors, into tumours that respond to immune checkpoint inhibition therapies.

cancer biology↗

bioRxiv2017

Blockade of insulin-like growth factors increases efficacy of paclitaxel in metastatic breast cancer.

Breast cancer remains the leading cause of cancer death in women due to metastasis and the development of resistance to established therapies. Macrophages are the most abundant immune cells in the breast tumor microenvironment and can both inhibit and support cancer progression. Thus, gaining a better understanding of how macrophages support cancer could lead to the development of more effective therapies. In this study, we find that breast cancer associated macrophages express high levels of insulin-like growth factors 1 and 2 (IGFs) and are the main source of IGFs within both primary and metastatic tumours. 75% of breast cancer patients show activation of Insulin/IGF-1 receptor signaling and this correlates with increased macrophage infiltration and advanced tumor stage. In patients with invasive breast cancer, activation of Insulin/IGF-1 receptors increased to 87%. Blocking IGF in combination with paclitaxel, a chemotherapeutic agent commonly used to treat breast cancer, showed a significant reduction in tumor cell proliferation and lung metastasis in a pre-clinical breast cancer model compared to paclitaxel monotherapy. Our findings provide the rationale for further developing the combination of paclitaxel with IGF blockers for the treatment of invasive breast cancer, and Insulin/IGF1R activation and IGF+ stroma cells as potential biomarker candidates for further evaluation.

cancer biology↗