Patricia Abrao Possik

• PhD
• Researcher at Brazilian National Cancer Institute

In melanomas, therapy resistance can arise due to a combination of genetic, epigenetic and phenotypic mechanisms. Due to its crucial role in DNA supercoil relaxation, TOP1 is often considered an essential chemotherapeutic target in cancer. However, how TOP1 expression and activity might differ in therapy sensitive versus resistant cell types is unk...

Breast cancer is the second most common cause of cancer-related deaths worldwide among women. Despite several therapeutic options, 15% of breast cancer patients succumb to the disease owing to tumor relapse and acquired therapy resistance. Particularly in triple-negative breast cancer (TNBC), developing effective treatments remains challenging owin...

Protein phosphorylation is an essential post-translational modification (PTM) regulating many biological processes at the cellular and multicellular level. Continuous improvements in phosphoproteomics technology allow the analysis of this PTM in an expanding biological content. Yet, up till now proteome data visualization tools are still very gene...

No effective targeted therapy is currently available for NRAS mutant melanoma. Experimental MEK inhibition is rather toxic and has only limited efficacy in clinical trials. At least in part, this is caused by the emergence of drug resistance, which is commonly seen for single agent treatment and shortens clinical responses. Therefore, there is a di...

Increased expression of the Microphthalmia-associated transcription factor (MITF) contributes to melanoma progression and resistance to BRAF pathway inhibition. Here we show that the lack of MITF is associated with more severe resistance to a range of inhibitors, while its presence is required for robust drug responses. Both in primary and acquired...

Treatment of BRAF mutant melanomas with specific BRAF inhibitors leads to tumor remission. However, most patients eventually relapse due to drug resistance. Therefore, we designed an integrated strategy using (phospho)proteomic and functional genomic platforms to identify drug targets whose inhibition sensitizes melanoma cells to BRAF inhibition. W...

To identify factors preferentially necessary for driving tumor expansion, we performed parallel in vitro and in vivo negative-selection short hairpin RNA (shRNA) screens. Melanoma cells harboring shRNAs targeting several DNA damage response (DDR) kinases had a greater selective disadvantage in vivo than in vitro, indicating an essential contributio...

During the first National Science and Technology Week held in 2004, science centers and museums, universities and schools engaged in activities with the idea of divulging science to the people. Demonstrations of the extraction of DNA from fruits were conducted in supermarkets in 11 Brazilian cities by two institutions, DNA Vai à Escola and Conselho...

Human melanocytic nevi (moles) are benign lesions harboring activated oncogenes, including BRAF. Although this oncogene initially acts mitogenically, eventually, oncogene-induced senescence (OIS) ensues. Nevi can infrequently progress to melanomas, but the mechanistic relationship with OIS is unclear. We show here that PTEN depletion abrogates BRAF...

Oncogene-induced senescence (OIS) is a growth arrest triggered by the enforced expression of cancer-promoting genes and acts as a barrier against malignant transformation in vivo. In this study, by a combination of in vitro and in vivo approaches, we investigate the role of OIS in tumours originating from the thyroid epithelium. We found that expre...

Melanocytic nevi frequently harbor oncogenic BRAF mutations, but only a minority progress to melanoma. In human melanocytes, persistent BRAF(V600E) expression triggers oncogene-induced senescence, which implies that bypass of oncogene-induced senescence is necessary for malignant transformation of melanocytes. We show that a subpopulation of primar...

Identification of differences in the gene expression patterns of Down syndrome and normal leukocytes. We constructed the first Down syndrome leukocyte serial analysis of gene expression (SAGE) library from a 28 year-old patient. This library was analyzed and compared with a normal leukocyte SAGE library using the eSAGE software. Reverse transcripta...

We used immunocytochemical and fluorescence assays to investigate the subcellular location of the protein encoded by Down syndrome critical region gene 2 (DSCR2) in transfected cells. It was previously suggested that DSCR2 is located in the plasma membrane as an integral membrane protein. Interestingly, we observed this protein in the endoplasmic r...

We discuss a proposal for an experimental, laboratory-based course in molecular biology aimed at familiarizing undergraduate students with scientific research. The main advantage of this course is that it provides students with good laboratory training through the development of a scientific project and the achievement of original results. The cour...

Abstract of the panel presented at the SBBq annual meeting (see attachament).