Application of nanotechnology and photodynamic therapy to enhance
the treatment efficacy of melanoma skin cancer
1,3
de Paula, L.B. ; Primo, F.L.
*e-mail: atedesco@usp.br
1,2
; Tedesco, A.C.
1*
1
Centro de Nanotecnologia e Engenharia Tecidual - Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto Universidade de São Paulo – USP – Av. Bandeirantes, 3900 Departamento de Química – Ribeirão Preto – SP –
2
Brasil. Departamento de Bioprocessos e Biotecnologia – Faculdade Ciências Farmacêuticas – Universidade Estadual
3
Paulista Júlio Mesquita Filho – UNESP – Araraquara – SP – Brasil. Departamento de Genética – Faculdade de
Medicina de Ribeirão Preto – Universidade de São Paulo – USP – Av. Bandeirantes, 3900 – Ribeirão Preto – SP –
Brasil
Keywords: Nanoemulsion, Chloroaluminum phthalocyanine, Drug delivery system, Photodamage.
Introduction
Melanoma, a cancer that arises from the
melanocytes, is one of the most aggressive skin
cancers with lower or absence of treatment response
leading to a fast metastases process [1]. Early
detection, surgery, or combinations of adjuvant
therapy have been proving to inducing better
outcomes; nonetheless, the prognosis of metastatic
melanoma remains poor [2]. Photodynamic therapy
(PDT) has the potential to meet many of the currently
unmet medical needs. Although still emerging as
clinical option for some later stage cancer treatment,
it has been proved to rich successful treatment and
clinical approved therapeutic procedure to be used
for the management of neoplastic and nonmalignant
diseases. PDT has been approved by the US Food
and Drug Administration (FDA) at almost two
decades ago, but still has an open field to the
development of new nano-drug delivery system
(DDS) [3]. In this work, we report the studies using
metastatic murine melanoma cell line (B16-F10)
treat by chloroaluminum phthalocyanine (ClAlPc)
photoactive entrapped a nanoemulsion (NE) as a
topical DDS, defining the best photosensitizer (PS)
concentration, incubation time and visible light
irradiation doses.
Results and Discussion
The NE obtained was of type oil in water (o/w) with a
high thermodynamic stability. The physical chemistry
parameters were analyzed as previously described
by Primo et al. [4]. The results show that the
incorporation of the PS in the DDS led to a small
increase on the average size of the colloidal
nanoparticles, which remained within the range of
the expected size distribution (141.80.8 nm). All of
these parameters were monitored for 30 days, which
demonstrated an adequate profile of the physicalchemistry stability to the samples stored at 4ºC.
These results demonstrate that the formulation is
promising as a DDS useful for clinical PDT trials.
Besides, the use of nanoemulsions as DDS is a new
trend in cosmetic, pharmaceutical, and therapeutic
procedures, for the controlled topical release of
drugs and active compounds to the skin and deep
dermal layers [5]. In vitro studies were carried out
under the with B16-F10 biological model. The
cytotoxicity index of the NE, at fixed ClAlPc
concentration, was first evaluated. The results
showed a total biocompatibility at 0.5 μmol/L ClAlPc
loaded NE, resulting in a cellular viability higher than
90% (biocompatible). Therapeutic assays were
performed under the same biological model with
melanoma cell line and the cellular viability was
obtained by MTT assay. Evaluation of the PDT light
effects was performed using a typical diode-laser
operating at 500 mW @ 660 nm output power at a
doses
range
from
100,
200
and
2
700 mJ/cm . The cellular viability decreased as a
function of the irradiation doses as expected.
Mitochondrial activity (MTT-test) describes a cellular
viability of 37% and 17% compared with the controls
(B16-F10 cells on RPMI 3%), which is related to the
association of the effects of photodamage based on
photodynamic mechanisms and cell injury. Our
findings support the conclusion of the efficacy of
both therapies in the inactivation of most malignant
cells in the cultured linage.
Conclusions
Stable nanoemulsion containing chloroaluminum
phthalocyanine (NE/ClAlPc) was successfully
prepared and subsequently tested for cell viability
using the murine melanoma (B16-F10) cell line. The
MTT assays showed significant cell viability
reduction while applying the PDT treatment at
increasing irradiation content. Moreover, further
reduction in cell viability was observed while applying
the PDT treatment. Our findings indicated that
advances in clinical oncology can been visage by
using PDT treatments.
Acknowledgements
We thank the Brazilian agencies for financial
support. L.B.P. was funded by the CNPq PhD project
140998/2011-0. F.L.P. was funded by the PIPEFAPESP project 2014/14231-7 (F.L.P.).
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2