Effects of 5-aminolevulinc acid in combination with photodynamic therapy and targeting agents in squamous oral cancer: development of a novel cancer therapy.
Progetto Oral cancer is an aggressive epithelial malignancy in the head and neck
region with squamous cell carcinoma according for 90%.
5ALA is a precursor of PpIX, endogenous cell PS, which radiated causes a
cytotoxic effect. The introduction of 5ALA leads to the
intracellular accumulation of PpIX. Cells with high rates of metabolic
activity as cancer cells, inflammatory cells and bacteria have
less FECH so the production of PpIX is more pronounced than healthy cells.
Overexpression of EGFR, occurring in up to 90% of
squamous cell tumours, correlates with impaired prognosis and radiation
resistance. The binding EGFR/EGF activates pathways that
facilitate cell proliferation, hamper apoptosis, promote angiogenesis,
invasion, metastasis. The anti-EGFR antibody cetuximab exerts
its therapeutic action adding to an anti-oncogenic activity the induction of an
antibody-dependent cytotoxicity. It is clinically
approved in combination with radiotherapy and TKIs. This activity
correlates with the elevated expression and activity in tumor cells
of the ABCG2 which controls the efflux of PpIX. Lapatinib, as other TKIs,
is a substrate for the ABCG2 transporter. 5ALA-PTD/lapatinib
combination decreased significantly the viability of neoplastic cells and this
provide a valid rationale to test 5ALA-PTD in association
with lapatinib or other TKIs to treat ABCG2 positive OSCC. Based on
preliminary results, we will perform the in vitro cultures of OSCC
CAL27 and OECM1, hGEC as normal control, and treatment with 5ALAPDT in association with targeting agents including cetuximab
to investigate their role in the tumor suppressive response in OSCC. After
treatments, the resulting photocytotoxicity, apoptosis, cell
cycle and ROS production will be assessed. We will also perform gene and
protein expression of heme pathways to find new biologic
markers. Cell lysates will be tested for levels of EGFR and VEGFR and their
downstream signaling pathways. The results obtained will
be analyzed with the data obtained from the cell toxicity assay using a panel
of targeting agents. After this analysis, the best target
selected able to improve the effect of 5ALA-PDT will be identified. OSCC
patients will be recruited and biopsies will be collected to
perform primary cultures. 5ALA-PDT treatment, in combination with
markers selected from the studies of HEME and EGFR/TKIs
pathways will be repeated on patient-derived OSCC. The second year the
research activity will be focused on in vivo study. OSCC
xenografts will be established from subcutaneously injected cell lines.
Accordingly with in vitro results, the optimal treatment
schedule using 5ALA-PDT in combination with targeted agent will be tested
in animal models. Finally, in order to improve thet ranslational relevance of
the in vivo findings, we will perform imaging studies to investigate if the
modulation of such tracer uptake in OSCC xenografts mey be able to early detect the efficacy of treatment.