Patricio Fuentes (firstname.lastname@example.org) attended University of Chile, where he earned a his PhD in Biochemistry focusing on neural precursor cell identity, and neuronal migration in the mouse model. After completion of the PhD, he moved to Boston where he carried out research on cell-extracellular matrix (ECM) interaction and brain development at Harvard Medical School. He next moved to Milan where he spent 5 years at the European Institute of Oncology (IEO), working on epigenetic and neurodevelopmental disorders. Since May of the last year he is a researcher at the Italian Institute of Technology (IIT, CGS@SEMM Milano) where he works on non-coding RNA and the mechanisms of chemo-resistance in pre-clinical models of triple negative breast cancer (TNBC). When not working Patricio enjoys going on hikes, partake in outdoors activities and barbecuing.
The thousands of cells that make up breast cancers have a wide variety of characteristics, some of which play a role in the dissemination (metastasis) of the primary tumor to other organs. This intra-tumoral heterogeneity is pervasive and makes clinical treatment challenging, given that identifying which cells are responsible for driving the metastases is difficult. In order to understand the molecular and cellular basis of breast cancer dissemination, our lab harnesses cutting edge technologies such as DNA barcoding and next-generation sequencing to tag, track and pinpoint the cells that are responsible for the spread of the main tumor into other organs. The precision of this approach will help us focus our research efforts and develop targeted treatments to tackle the primary and metastatic breast tumors.
Our goal is to identify differences between normal and cancerous breast tissues, determine their implications, and use this information to pave the way for designing suitable and targeted clinical interventions in breast cancer patients.
Triple-negative breast cancer (TNBC) accounts for 15%-20% of all BC and is the most aggressive subtype. TNBC is defined by the absence on breast cancer cells of three receptors: estrogen, progesterone and human epidermal growth factor receptor. Hence, compared with receptor-positive carcinomas, TNBC is devoid of clear therapeutic targets. Its increased aggressiveness, drug resistance, relapse, and metastasis are associated with the presence of cancer stem cells (CSCs) and the intra-tumor heterogeneity (ITH).In consequence, its treatment is an arduous task that results in poorer outcomes when compared to other cancer subtypes. TNBC patients usually receive pre-operative neoadjuvant treatment (NACT) involving the administration of chemotherapeutic drugs before surgery. The outcome for the majority of those who still have residual disease after treatment is poor and about 60% of them develop resistance to chemotherapy. Therefore, novel targeted therapeutic approaches are critically required.
Project 1 : Chemoresistance evolution in Triple-Negative Breast Cancer (TNBC)
Tumours are complex ecosystems. Intratumoral heterogeneity arises through genetic and non-genetic processes that result in a single tumor harboring diverse subclones, which can evolve along complex trajectories.
My first aim (figure 1) is to in vivo monitor how clonal architecture changes in response to chemotherapy treatment. To this end, I employ barcoded (i.e., tagged with a random DNA sequence) human mammary carcinoma cells and both treatment-naïve and chemo-treated TNBC orthotopic xenograft models in combination with genome sequencing. I have optimized the purification methods for primary tumors and for their matched metastases in these models. Our preliminary data reveal alterations in clonal architecture when comparing primary tumors subjected to chemotherapy with their corresponding metastases.
Figure 1. Schematic outline of the experimental design used to track clonal dynamics in response to treatment
Project 2: Nanoparticle delivery of microRNAs as a Triple-Negative Breast Cancer Therapy
The implementation of high-throughput genomic sequencing approaches have revealed that the “non-protein portion” of the genome is copied into thousands of non-coding RNA (ncRNA) molecules that regulate fundamental biological processes as well as playing a critical role in the emergence of human diseases, such as cancer. microRNAs (miRs) are small ncRNAs (18-23 nts) that regulate gene expression by binding to a target mRNA and then triggering translational silencing or degradation.
My second aim (figure 2) consists in implementing a nanotechnology-based therapeutic strategy for active targeting of TNBC cells. To do so, I will collaborate with Dr Nicola Tirelli’s group (Polymers and Biomaterials research line; IIT Central Research Labs; Genova) to explore the potential of Chitosan (CS)/Hyaluronic acid (HA) nanoparticles (NPs) for the selective delivery of specific RNA moyeties (i.e. miRNAs or lncRNAs) acting as TNBC therapeutic agents. The combination of CS and HA is promising due to the low toxicity of the former and the receptor-mediated internalization of the latter, thus allowing the selective delivery of the therapeutic miRNA into cells that overexpress HA receptors, notably CD44. Cell surface expression of CD44 is significantly higher in cancer and, particularly in breast tumors, correlating with metastasis and drug resistance; further, CD44 is a well-known marker of CSCs and often reported to accompany the EMT transition. Thus, we foresee that the combination of miRNA coated CS/HA-NPs with surgery and chemotherapy will form the core of a potentially promising and clinically suitable treatment of highly aggressive and resistant TNBC tumors.
Altogether, the technologies mentioned above allow us to dissect the mechanisms underlying intra-tumor heterogeneity and the clinical consequences of intra-tumor diversity with special emphasis on tumor progression and chemotherapeutic responses.
Figure 2. The Chitosan/HA Nanoparticles are designed to have HA (Green) on the Surface and a Core made of Two Polymers forming a Ternary Complex with RNA (Blue). Chitosan is used in the production of polyplexes for the delivery of nucleic acids; such structures can be binary complexes, or may include also other polyelectrolytes, such as, hyaluronic acid (HA), in a ternary complex. The coexistence of chitosan and HA is promising as it combines the low toxicity of the former with the receptor-mediated internalization of the latter, thus allowing for the targeted delivery into cells, such as CD44, overexpressing HA receptors, which is upregulated in a number of tumors.