PD-L1 expression is regulated by both DNA methylation and NF-kB during EMT signaling in non-small cell lung carcinoma

Tumor cells, which undergo Epithelial-mesenchymal transition (EMT) acquire increased capacities of proliferation, invasion and have the ability to generate metastases by escaping the immune system during their systemic migration. To escape the immune system, cancer cells may induce tolerance or resist elimination by immune effectors via multiple mechanisms and we hypothesized that EMT may control the expression of immune checkpoint inhibitors, then promoting immune evasion. PD-L1 (programmed cell death ligand 1) but not PD-L2 nor Galectin 9 or Death receptor (DR4, DR5 and Fas) and ligands (FasL and TRAIL) expression was up-regulated during cytokine-driven EMT in a reversible manner. Moreover PD-L1 is overexpressed in VIMENTIN positive NSCLC tissues. We also demonstrated that the expression of PD-L1 required both TNFα and TGFβ1. Indeed, TGFβ1 decreased DNMT1 content and that resulted in PD-L1 promoter demethylation whereas TNFα induced the NF-κB pathway that promoted expression of demethylated PD-L1 promoter.

Metabolic inhibitors accentuate the anti-tumoral effect of HDAC5 inhibition

The US FDA approval of broad-spectrum histone deacetylase (HDAC) inhibitors has firmly laid the cancer community to explore HDAC inhibition as a therapeutic approach for cancer treatment. Hitting one HDAC member could yield clinical benefit but this required a complete understanding of the functions of the different HDAC members. Here we explored the consequences of specific HDAC5 inhibition in cancer cells. We demonstrated that HDAC5 inhibition induces an iron-dependent reactive oxygen species (ROS) production, ultimately leading to apoptotic cell death as well as mechanisms of mitochondria quality control (mitophagy and mitobiogenesis). Interestingly, adaptation of HDAC5-depleted cells to oxidative stress passes through reprogramming of metabolic pathways towards glucose and glutamine. Therefore, interference with both glucose and glutamine supply in HDAC5-inhibited cancer cells significantly increases apoptotic cell death and reduces tumour growth in vivo; providing insight into a valuable clinical strategy combining the selective inhibition of HDAC5 with various inhibitors of metabolism as a new therapy to kill cancer cells.

Abstract P1-06-09: Relationships between breast cancer subtypes and expression of autophagy related genes

Background:

Breast cancer (BC) is a heterogeneous disease and can be classified according to the expression of four genes: estrogen receptor (ER), progesterone receptor (PGR), human epidermal growth factor receptor 2 (HER2) and marker of proliferation KI67. Four groups of BC have been described: Luminal A (ER+ or PGR+, KI67- HER2-), Luminal B (ER+ or PGR+, KI67+ or HER2+), HER2 (ER- HER2+) and triple negative (ER- PGR- HER2-). Autophagy is a lysosomal degradation pathway which plays a crucial dual role in tumorigenesis, producing pro-survival or pro-death activity. Altered autophagy has been observed in BC but no study has described transcript level variations of "autophagy genes" according to sub-groups. In order to further explore those alterations, we analyzed gene expression of 40 "autophagy genes" in normal and tumor cells using public transcriptomic data.

Samples and Methods:

5497 transcriptomes were obtained from raw data downloaded from public databases. Two distinct Affymetrix series were built after GC-RMA normalization: one from HG-U133A arrays (n=2806) and one from HG-U133 plus2 arrays (n=2691). Each series was standardized with the Aroma R package that was designed to normalize multicenter extremely large Affymetrix data sets. The same computations were performed in the two data set in order to cross-validate the results. Samples were classified with a reduced number of genes (such as for St Gallen classification) and with classifiers using 50 or more than 300 genes (PAM50, CIT and IntClust centroids).

Results:

In each of the two series, there were about 500 Basal, 300 HER2, 1800 Luminal tumors and 100 normal epithelial breast cells. Positivity or negativity of four genes (ER, PGR, KI67, HER2) produced robust classifications concordant with PAM50 classification based upon centroids. Within the 40 "autophagy genes" studied, at least 10 genes were significantly correlated with one or two sub-groups: ATG3 and ATG9A were associated with ER- tumors including basal group; ATG2B , BECN1 and ULK2 were positively correlated with ER expression and luminal subtypes; ULK1 and RAB24 were associated with ER+HER2+ tumors and MAP1LC3B and ATG5 with ER-HER2+ subgroup; GABARAPL1 was more expressed in normal breast tissue than in cancer cells.

Discussion:

Exploring autophagy in large-scale transcriptome data, we confirmed a previous result showing that GABARAPL1 expression is reduced in breast cancer cells compared with the normal epithelial cells. Interestingly, transcript levels of "autophagy genes"were not evenly distributed among the different tumor subtypes. For instance, some genes were preferentially expressed in ER+ subtypes and others in ER- tumors, suggesting that autophagy might play different roles in the different subgroups, providing different potential targets for therapy.

Citation Format: Feugeas J-P, Belmiloudi S, Boyer-Guittaut M, Peixoto P, Hervouet E. Relationships between breast cancer subtypes and expression of autophagy related genes [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-06-09.

HDAC5 is required for maintenance of pericentric heterochromatin, and controls cell-cycle progression and survival of human cancer cells

Histone deacetylases (HDACs) form a family of enzymes, which have fundamental roles in the epigenetic regulation of gene expression and contribute to the growth, differentiation, and apoptosis of cancer cells. In this study, we further investigated the biological function of HDAC5 in cancer cells. We found HDAC5 is associated with actively replicating pericentric heterochromatin during late S phase. We demonstrated that specific depletion of HDAC5 by RNA interference resulted in profound changes in the heterochromatin structure and slowed down ongoing replication forks. This defect in heterochromatin maintenance and assembly are sensed by DNA damage checkpoint pathways, which triggered cancer cells to autophagy and apoptosis, and arrested their growth both in vitro and in vivo. Finally, we also demonstrated that HDAC5 depletion led to enhanced sensitivity of DNA to DNA-damaging agents, suggesting that heterochromatin de-condensation induced by histone HDAC5 silencing may enhance the efficacy of cytotoxic agents that act by targeting DNA in vitro. Together, these results highlighted for the first time an unrecognized link between HDAC5 and the maintenance/assembly of heterochromatin structure, and demonstrated that its specific inhibition might contribute to increase the efficacy of DNA alteration-based cancer therapies in clinic.

Doença de Dupuytren. Revisão de 100 doentes operados

A Doença de Dupuytren observa-se com frequência nesta região. Dada a sua incidência, a diminuição da capacidade de trabalho que pode provocar e o elevado número de casos tratados cirurgicamente, decidimos reavaliar os pacientes, tentando identificar factores etiológicos e o resultado do tratamento.

Foi efectuado um estudo de revisão clínico e de registos em processo de 100 casos, operados entre Fevereiro de 2002 e Dezembro de 2005 no Serviço de Ortopedia do Hospital do Vale do Sousa.

Após discussão com os ortopedistas assistentes, todos os dados relevantes recolhidos foram tratados estatisticamente em colaboração com o Serviço de Bioestatística da Faculdade de Medicina do Porto.

Os resultados são precedidos de uma perspectiva histórica e um sumário da etiologia, evolução, estadiamento, classificação e opções de tratamento da doença de Dupuytren.