Dental pulp stem cells used to deliver the anticancer drug paclitaxel
Salehi et al. Stem Cell Research & Therapy
Dental pulp stem cells used to deliver the anticancer drug paclitaxel
Hamideh Salehi 0 1
Siham Al-Arag 0 1
Elodie Middendorp 1
Csilla Gergely 2
Frederic Cuisinier 1
Valerie Orti 1
0 Equal contributors
1 LBN, University of Montpellier , Montpellier , France
2 L2C, University of Montpellier , CNRS, Montpellier , France
Background: Understanding stem cell behavior as a delivery tool in cancer therapy is essential for evaluating their future clinical potential. Previous in-vivo studies proved the use of mesenchymal stem cells (MSCs) for local delivery of the commonest anticancer drug, paclitaxel (PTX). Dental pulp is a relatively abundant noninvasive source of MSCs. We assess dental pulp stem cells (DPSCs), for the first time, as anticancer drug carriers. Confocal Raman microscopy is a unique tool to trace drug and cell viability without labeling. Methods: Drug uptake and cell apoptosis are identified through confocal Raman microscope. We traced translocation of cytochrome c enzyme from the mitochondria, as a biomarker for apoptosis, after testing both cancer and stem cells. The viability of stem cells was checked by means of confocal Raman microscope and by cytotoxicity assays. Results: In this study, we prove that DPSCs can be loaded in vitro with the anticancerous drug without affecting their viability, which is later released in the culture medium of breast cancer cells (MCF-7 cells) in a time-dependent fashion. The induced cytotoxic damage in MCF-7 cells was observed consequently after PTX release by DPSCs. Additionally, quantitative Raman images of intracellular drug uptake in DPSCs and MCF-7 cells were obtained. Cytotoxic assays prove the DPSCs to be more resistant to PTX as compared to bone marrow-derived MSCs, provided similar conditions. Conclusions: Applications of dental stem cells for targeted treatment of cancer could be a revolution to reduce morbidity due to chemotherapy, and to increase the efficacy of systemic cancer treatment.
Raman spectroscopy; Dental pulp stem cells; Cancer; Paclitaxel; Apoptosis
Cancer is a complex heterogeneous disease; the survival of
cancer patients is still poor with high mortality and
morbidity rates despite recent therapeutic advances. The
morbidity also results from serious side effects due to the
use of nonspecific anticancerous drugs. Furthermore, in
many cases, the poor survival of patients greatly relates to
the inability to deliver drugs to the metastatic sites, away
from the main tumor mass [
]. It is, therefore, crucial to
develop new delivery strategies for chemotherapeutic
drugs in clinical use.
Paclitaxel (PTX) is one of the most effective
broadspectrum anticancer drugs indicated for solid tumor
malignancies, including lung, gastric, ovarian, and
metastatic breast cancer [
]. PTX is a microtubule-stabilizing
agent as it is believed to bind to the β-tubulin unit of
the microtubules inducing mitotic arrest [
toxicity includes bone marrow suppression, alopecia
(100% of patients), and hypersensitivity reactions. It can
also cause neurotoxicity, myalgia, and other side effects
]. The key goal of cancer chemotherapy consists of
selectively localizing the drug’s effect toward the tumor
in order to reduce its collateral toxicity [
]. Over the
past decades, many tumor-selective approaches have
been investigated, as antibodies, peptides for targeting
tumor antigens, nanoparticles, or cellular therapy [
Stem cells that could be expanded and modified ex vivo,
and transplanted in vivo, encourage attempts to treat
complex lethal diseases like cancer .
Mesenchymal stromal cells (MSCs) have recently gained
great interest as an anticancer tool. Apart from their
immunomodulatory roles, anti-inflammatory effects,
secretion of bioactive molecules, and multilineage differentiating
capability under appropriate conditions, their significant
homing ability toward tumor and metastasis sites makes
MSCs a new alternative to deliver anti-tumor agents [
]. Administration of MSCs has been associated
with decreased tumor growth when injected systemically or
directly in contact with tumors, suggesting their systemic
effect and inhibition of tumor proliferation [
Moreover, independently of their controversial role in inhibiting
or promoting cancer growth, mesenchymal stem cells can
be used as a “Trojan horse” to vehicle and deliver
conventional anti-tumor agents into the cancer cells because of
their ability to migrate, localize, and survive in cancer
tissue, and their resistance to the chemotherapeutic drugs
]. When primed with PTX, human MSCs
derived from the bone marrow acquire strong anti-tumor
activity through their capacity to uptake, deliver, and
subsequently release the internalized drug into the tumor
microenvironment, thus impairing tumor growth [
9, 10, 17,
]. These cells have shown sensitivity to the
antiproliferative activity of PTX but were strongly resistant to the
drug’s cytotoxic effects even at high concentrations (> 10
μg/ml PTX) [
In addition to the bone marrow MSCs, adipose
tissuederived mesenchymal stem cells (ADSCs) and amniotic
mesenchymal stem cells (AMSCs) have been investigated
]. The potential use of ADSCs in cancer patients,
especially those undergoing invasive surgery, could be
affected by the disease and/or the treatment followed.
Cancer patients lose their fatty tissue, which renders the
autologous use of ADSCs unfeasible in this case. For
AMSCs from a fetal or maternal origin, some issues have
been proposed toward the isolation from different
origins which may differentially express some functions
not typical for MSCs, in addition to the complicated
manipulation of these cells for clinical use. Allogenic or
autologous stem cell transplantation may be proposed
for therapy. For this reason, allogenous in-vitro
expanded MSCs do not seem a promising option since
xenogeneic antigens might trigger undesirable immune
responses. Therefore, most of the completed clinical
trials are based on autologous treatments .
Dental pulp is an interesting source of mesenchymal
stem cells, due to the large abundance of cells from one
tooth and the noninvasive isolation methods compared to
other adult tissue sources [
]. Pulp tissue from human
third molars, exfoliated deciduous or supernumerary
teeth, represent an easy source for harvesting MSCs. The
properties of dental pulp stem cells (DPSCs) distinguish
them as one of the most accessible cell sources for
cellbased therapy [
Understanding the mechanism and behavior of MSCs
and tracking them to check their efficacy in cancer
treatment are essential for assessing their future clinical
potential. Confocal Raman microscopy is the method able to
track living cells [
5, 6, 27–29
] without a need for labeling.
The laser beam being focused down to a small spot on the
specimen leads to high spatial resolution and unique
compositional sensitivity. This method allows cells’
analysis according to different vibrational spectra owing to
differences in the biochemical composition of the
molecules. The drug’s specific Raman signature enables its
precise detection in the cell [
5, 6, 27, 28
]. Here we used
MSCs of the dental pulp to assess for the first time
whether they can be a promising delivery vehicle for PTX.
We evaluate also by confocal Raman microscopy and
cytotoxic assays the effect of PTX on the dental pulp and
bone-marrow-derived mesenchymal stem cells (DPSCs
and BM-MSCs), and the cytotoxic damage induced by
using the in-vitro conditioned medium released from
drug-loaded DPSCs to MCF-7 breast cancer cells.
Human dental pulp stem cells: culture and characterization
Human wisdom teeth extracted for orthodontic reasons
were recovered from healthy patients (15–18 years old).
Written informed consent was obtained from the parents
of the patients. This protocol was approved by the local
ethical committee (Comité de Protection des Personnes,
Montpellier Hospital, France). Tooth surfaces were
cleaned using 2% chlorhexidine and cut around the
cementum–enamel junction using sterilized discs. Teeth
were then broken into two pieces to reveal the pulp
chamber. The pulp tissue was gently separated from the crown
and root, and then digested in a solution of 3 mg/ml
collagenase type I and 4 mg/ml dispase for 1 h at 37 °C. The
solution was then filtered through 70-μm Falcon strainers
and added to αMEM supplemented with 10% fetal bovine
serum (FBS), 100 U/ml penicillin, 100 μg/ml streptomycin
with the addition of 1 ng/ml basic fibroblast growth factor
(bFGF) and placed in 75-ml flasks. Cells were incubated
for 1 week at 37 °C with 5% CO2. Nonadherent cells were
removed by a change of medium 24 h after cell seeding.
Cells were cultivated for 24 h on polished calcium fluoride
(CaF2) substrates (Crystran Ltd, Dorset, UK). The cultured
cells were washed three times with phosphate buffered
saline (PBS) to remove the culture medium, and then
fixed with 2% paraformaldehyde for 15 min and rewashed
with PBS before Raman imaging.
After 1 week, subconfluent cells were collected and
analyzed for minimal criteria to define human
mesenchymal stem cells, such as adherence to plastic, expression of
cell surface antigens, and ability to differentiate into
osteoblasts, adipocytes, and chondroblasts in vitro [
The antigen profiles of cultured DPSCs were analyzed by
detecting the expression of the cell surface markers CD90,
CD146, CD117, and CD45 using flow cytometry [
CD90 is a widely accepted marker for mesenchymal stem
cells, CD146 is a marker expressed in perivascular
mesenchymal stem cells, CD117 is the receptor of stem cell
factor, and CD45 is a marker of hematopoietic cells,
mainly myeloid progenitors. The latter has been used to
demonstrate the absence of contamination by CD45+
hematopoietic progenitors. Cells were controlled for
pluripotency with in-vitro osteogenic, adipogenic, and
chondrogenic differentiation essays following a previously
described protocol .
Human bone marrow mesenchymal stem cells
Mesenchymal stem cells expanded from human bone
marrow stem cells, at their second passage, were obtained from
the Institute for Regenerative Medicine and Biotherapy
(IRMB, Montpellier, France). These were cultured in
αMEM supplemented with 10% FBS, 100 U/ml penicillin,
100 μg/ml streptomycin, with the addition of 1 ng/ml
bFGF, and were placed in 75-ml flasks. The cells were
maintained at a temperature of 37 °C in humidified,
concentrated CO2 (5%) atmosphere. All experiments were
done between passages 2 and 8.
MCF-7 cell culture
MCF-7 cells, derived from a metastatic breast cancer
patient in 1970, were the first cancer cell line capable of
living longer than a few months and became a standard
model in cancer research laboratories [
]. MCF-7 cells
were grown in 75-cm2 culture flasks (VWR, Strasbourg,
France) in a medium containing 7 ml Dulbecco’s Modified
Eagle’s Medium (DMEM) (Thermo Fisher, Strasbourg,
France), 20% FBS and 1% antibiotics (streptomycin 100
μg/ml, penicillin 100 U/ml) at 37 °C and 5% CO2.
Accordingly, to transfer the conditioned medium from
stem cells to cancer cells, the medium was changed
gradually in such a way that after 2 weeks MCF-7 cells
were cultivated in αMEM. Cells were seeded onto
polished calcium fluoride (CaF2) substrates (Crystran Ltd,
Dorset, UK) for Raman imaging and after 24 h the cells
adhered well on the CaF2 substrate. MCF-7 cells were first
incubated in a solution of conditioned medium released
by the DPSCs, and then rinsed with PBS before being
transferred under the confocal Raman microscope.
Priming with paclitaxel
In our experiments, 10 μM paclitaxel (Taxol; Teva
Pharmaceutical Ind., Tel Aviv, Israel)—equivalent to the
clinically used amount—was added in cell culture medium
]. DPSCs were incubated for 12 h with 10 μM PTX. The
culture medium was then removed, the cell culture was
rinsed with PBS to remove noninternalized drug, and a
fresh culture medium was added for 4 h. Next, MCF-7
were incubated for 3 h with the conditioned medium
(CM) containing the PTX released from the DPSCs. For
the cytotoxicity assays, DPSCs or BM-MSCs were
incubated for 12 h with PTX at a concentration of 10 μM for
In-vitro cytotoxicity assay on stem cells
The effect of PTX on cell viability was evaluated by the
Thiazolyl Blue Tetrazolium Bromide (MTT) assay
(M2128; Sigma-Aldrich, USA). DPSCs and bone-marrow
derived MSCs were seeded on a 96-well plate (30,000
cells/well) and cultured for 12 h in the presence of PTX
(concentration of 10 μM). Cell viability was calculated as
the ratio between the absorbance of treated and control
DPSCs. Mean and standard deviation (SD) values were
generated from three replicates. Each experiment was
performed at least three times. Representative results of
a multiple experiments are shown.
tetrazolium bromide) was dissolved in PBS at 5 mg/ml and filtered
to sterilize and remove a small amount of insoluble residue
present in some batches of MTT. At the times indicated in
the following, a stock MTT solution (10 μl per 100 μl
medium) was added to all wells, and plates were incubated
at 37 °C for 4 h. After 3–4 h at 37 °C for MTT cleavage, the
formazan product was solubilized by adding 0.1 ml of 0.04
N HCl isopropanol to the wells and mixing it thoroughly to
dissolve the dark blue crystals [
]. After less than 1 h
at room temperature the plates were read on an ELX800
Micro Elisa reader (BioTek, Winooski, VT, USA), using a
wavelength of 540 nm.
Raman data acquisition and analysis
Raman spectra were collected using a Witec Confocal
Raman Microscope System alpha 300R (Witec Inc., Ulm,
Germany). Excitation in confocal Raman microscopy is
generated by a frequency-doubled Nd:YAG laser
(Newport, Irvine, CA, USA) at a wavelength of 532 nm. The
incident laser beam is focused onto the sample through a
60× NIKON water immersion objective having a
numerical aperture of 1.0 and a working distance of 2.8 mm
(Nikon, Tokyo, Japan). The laser power after the objective
is 15 mW but the power absorbed by cells in PBS is lower.
The spatial resolution and depth resolution are 300 nm
and 1 μm, respectively. The mixed Raman and Rayleigh
scattered radiation was then passed through an edge filter
to block the Rayleigh radiation from the Raman signal.
The acquisition time of a single spectrum was set to 0.5 s.
An area of 150 × 150 points per image was recorded
leading to a total of 22,500 spectra for one image, each
spectrum corresponding to a spatial unit defined as a
voxel. Data acquisition was performed using Image Plus 2.
08 software from Witec.
Raman data analysis is based on three methods. The
first method provides integrated Raman intensities in
specific spectral regions, in particular that of the C–H
stretching mode providing a chemical map. Data
processing is performed using Image Plus software from
Witec. Using a look-up table, an image is created:
bright yellow hues indicate the highest intensities and
orange hues the lowest integrated intensities of the
The second method is K-means cluster analysis
(KMCA). K-means clustering partitions data into K
mutually exclusive clusters. The K-mean treats each
observation in the data set as an object having a location in space.
It finds a partition in which objects within each cluster are
as close to each other as possible, and as far from objects
in other clusters as possible. KMCA was realized using
Witec Project Plus (Ulm, Germany) software.
As a third analysis method, the spectral correlation
matrix was calculated [
] to find the most similar
spectrum to the reference spectrum of PTX. To quantify
the similarity, as a “distance”, Pearson’s correlation
coefficient was calculated for each pair of spectra, given by the
r ¼ qffiPffiffiffiffiffiiNffi¼ffiffi1ffiffiðffiffiffiffiiffi−ffiffiffiXffiffiffiffiÞffi2ffiffiffiffiffiffiffiNffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi2ffiffi
x Pi¼1ðyi−Y Þ
where N is the number of points within the spectrum, xi
and yi are the individual points, and X and Y are the mean
value of each spectrum. The value of r can vary between −1
and 1, and thus it can be expressed as a percentage ranging
from −100% (no correlation) to 100% (the perfect match).
From these values, a pseudo-color map can be constructed,
reflecting the quantified similarities. All correlation
calculations were performed with a homemade code written in
MatLab (Math Works, Inc., Natick, MA, USA).
Data are expressed as means, and when required the
differences between mean values were analyzed by one-way
ANOVA test performed by the Sigmaplot program (Systat
software, San Jose, CA, USA). p < 0.05 was considered
Cell viability results on dental pulp stem cells, bone marrow stem cells and breast cancer cells
Cell viability of dental pulp and bone marrow-derived
stem cells was evaluated by MTT assay. MCF-7 cells were
also tested as positive control. Optical densities at 540 nm
were determined for all types of cells, treated and
untreated with PTX, to compare their viability under the
same conditions. The results show a higher viability for
DPSCs as compared to those of BM-MSCs and MCF-7
cells, and a significant difference is found in their behavior
after treatment with PTX.
For each cell type, we calculated the cell viability
percentage as the ratio of the optical density of the test sample to
the optical density of solvent control by the following
Optical density of test sample
ðoptical density of test−optical density of blankÞ 100:
Cell viability ¼ Optical density of solvent control
ðoptical density of control−optical density of blankÞ
According to this formula, cell viability of DPSCs was
found to be 98% while that of BM-MSCs was 83%,
compared to 58% for the MCF-7 cells, as shown in Fig. 1.
Raman imaging results
Although the spectral contrast between cellular
components is relatively small, as they are very close in terms of
Raman vibrations, still it is possible to reveal very small
chemical differences between the various constituents of
the cell. For a biological sample, the complex constituents
(e.g., DNA, proteins, and lipids) in a cell generate a
molecular fingerprint in the Raman spectra. Raman
spectral maps of individual cells [
] and localization of
intracellular nanoparticles [
] have been achieved.
The average spectra of mitochondria, cytoplasm, and
nuclei, calculated by KMCA, are shown in Fig. 2: the
spectral peak at 750 cm−1 corresponds to the symmetric
breathing of tryptophan (protein assignment), at 780 cm−1
is assigned to the (O–P–O) stretching DNA, at 1128 cm−1
is the ν(C–C) skeletal acyl backbone in lipid, at 1312 cm−1
is the (CH3CH2) twisting mode of lipid, and at 1335 cm−1
is adenine, guanine (ring breathing modes in the DNA
bases), as reported in the literature [
]. The relative ratio
between these peaks would help to distinguish between
the different cell organelles.
For a better follow-up, we summarize here the main
steps of the experiments we have performed:
Step 1: Paclitaxel is added to DPSCs (12-h incubation
with 10 μM paclitaxel). DPSC uptake of the anticancer
drug is monitored (Fig. 3).
Step 2: DPSCs release paclitaxel into fresh culture
medium. After the release of paclitaxel, this medium is
called conditioned medium (Figs. 4 and 5).
Step 3: MCF-7 is incubated in conditioned medium
containing paclitaxel (Figs. 6 and 7).
Step 1: First, the ability of stem cells to uptake a high
concentration of the anticancer drug is verified. After
incubation for 12 h with 10 μM paclitaxel, DPSCs are rinsed
five times with culture medium and three times with PBS.
Figure 3a shows a DPSC Raman image after step 1. It
refers to the total integrated Raman intensities in specific
spectrum regions (2800–3000 cm−1) corresponding to the
C–H mode. By choosing the specific CH mode spectral
region in the sum filter tool, we could create an image
based on integrated Raman intensities of the C–H mode.
In Fig. 3a, bright yellow hues indicate high intensities of
intracellular C–H stretching modes, while dark hues (no
C–H) correspond to PBS. Figure 3b shows paclitaxel
uptake by DPSCs. The red pixels correspond to the
intracellular drug. The drug map is calculated by K-mean
cluster analysis (KMCA), a method described in previous
]. To obtain information about cellular
viability, a specific Raman approach is applied based on
the detection of released cytochrome c outside of the
mitochondria on the apoptotic path [
]. Briefly, a
cytochrome c map is constituted based on the Pearson’s
correlation coefficient map obtained from the reference
Raman spectrum of cytochrome c and the whole spectra
of the image. Figure 3c depicts the cytochrome c map, the
red pixels marked by black arrows being the positions
with a high concentration of intracellular cytochrome c. If
the cell is going through apoptosis, the mitochondrial
cluster should not be superimposed on the cytochrome c
map; that is, cytochrome c is released from the
mitochondria when the cell enters through apoptosis. If
cytochrome c is colocalized with the mitochondrial cluster,
there is no apoptosis. Figure 3d shows the mitochondrial
cluster obtained by KMCA. The superposition of images
from Fig. 3c, d is presented in Fig. 3e, clearly indicating that
the mitochondrial cluster overlays completely all of the
cytochrome c, which is the case for nonapoptotic cells. All
of the 15 analyzed DPSCs showed uptake of paclitaxel
Step 2: DPSCs were kept in the culture medium for 4 h
to release the paclitaxel. After rinsing in PBS, cells were
transferred to the Raman microscope to verify whether all
of the paclitaxel was released from the DPSCs. Figure 4
shows two DPSCs in PBS. Figure 4a presents the total
integrated Raman intensities corresponding to the C–H
mode of two cells. Paclitaxel’s higher concentration
corresponds to red pixels in Fig. 4b, where the two cells are
marked with ovals. Cell 2 shows intracellular paclitaxel
indicated by a few pixels, while the other cell has no
It is of interest to check DPSC viability after their
incubation in paclitaxel-containing culture medium and the
release of paclitaxel (Fig. 5). As for cells of Fig. 4, some
paclitaxel is still present in the cells even after 4 h. The
Raman map of cytochrome c and the cluster of
mitochondria are perfectly superposed (Fig. 5e). This indicates that
cytochrome c is still inside mitochondria and that
apoptosis has not yet started.
Step 3: Breast cancer cells (MCF-7 cells) were
incubated for 3 h in the culture medium—namely the
conditioned medium (CM)—containing the paclitaxel released
by DPSCs. The same number of cells for MCF-7 cells and
DPSCs was used for each set of experiments.
Figures 6b and 7 showed MCF-7 cells containing
paclitaxel (pink pixels). A total of 36 cancerous cells out of 42
showed the presence of paclitaxel. In Fig. 6e, the partial
superposition of the mitochondrial cluster on the
cytochrome c correlation map indicates the start of apoptosis.
Our work addresses the quest for powerful strategies for
carrying therapeutic agents straight to the targeted tumor
using mesenchymal stem cells as vehicles, and consequently
for local delivery of drugs at therapeutic concentrations.
This has been proposed and validated by previous in-vitro
10, 17, 20–25, 45
] and in-vivo studies [
10, 21, 46
for bone marrow-derived MSCs. DPSCs as an easy
noninvasive source of mesenchymal stem cells are a promising
cargo for drugs. The path of paclitaxel (PTX), a classical
anticancer drug, transported by DPSCs and absorbed by
MCF-7 cells, was successfully monitored by means of
confocal Raman microscopy. This label-free imaging method
enabled detection of the cellular organelles (mitochondria),
biological molecules, such as cytochrome c, and also
tracing of the drug PTX within the cell [
5, 6, 27
showed a great capacity to uptake PTX. The cytotoxic
assays showed that DPSCs were found more resistant to
PTX cytotoxicity compared to BM-MSCs under the same
We developed a Raman spectroscopic imaging technique
to detect intracellular PTX while simultaneously verifying
the viability of DPSCs by monitoring the eventual release of
cytochrome c from the mitochondria as one path of cell
]. After PTX uptake, the viability of the relevant
cell was checked and, surprisingly, despite the high
concentration of drug, no apoptosis was observed in DPSCs,
demonstrating their robustness and appropriateness to vehicle
PTX. Previous research showed that PTX treatment does
not induce apoptosis in human bone marrow MSCs [
17, 21, 23
], and no perceivable effective concentration could
be determined to initiate apoptosis within those cells [
We observed the release of PTX by DPSCs during 4 h
in the culture medium. DPSCs act as a reservoir for
PTX, and the cellular concentration of drug decreases
within 4 h. This reservoir after being removed to a fresh
culture medium starts to release its load, the drug and
specific factors near the breast cancer cells. Paclitaxel
was detected in the MCF-7 cells by Raman microscopy,
and apoptosis was observed. In total, 100% of the DPSCs
were successfully loaded with the drug, while almost
86% of the MCF-7 cells uptake it from the conditioned
medium. The transportation of drug by DPSCs might
have an effect on drug bioavailability, as the apoptosis
could be observed already after 3 h in conditioned
medium released from DPSCs (step 3). The drug
concentration in the secreted vesicles after 3-h
incubation with DPSC-CM should be equal to or higher than
0.5 μM [
To the best of our knowledge, the current work is the
first presenting a DPSC model as a paclitaxel delivery
vehicle. The other novelty of our proof of concept is the
use of chemical mapping of cells to visualize PTX inside
the living cells without labeling but based on Raman
biochemical signals. Fluorescence labeling as an alternative
method is not possible for small drug particle tracking
without losing its activity, mainly because the
fluorescence labels are bigger than the active molecules, and
thus their introduction may change the molecule’s
Our results point toward the auspicious use of DPSC cells
for cancer therapy. These cells are indeed efficient vehicles
having the ability to uptake, migrate toward the cancer, and
deliver paclitaxel without undergoing apoptosis. Raman
spectroscopy can be further used to reveal the effect of
paclitaxel exposure upon the function and viability of stem
cells. Injection of DPSCs for targeted drug delivery against
cancer cells is a promising approach to avoid the side
effects of systemic PTX delivery and increase the efficacy of
ADSC: Adipose tissue-derived stem cell; AMSC: Amniotic mesenchymal stem
cell; BM-MSC: Bone marrow-derived mesenchymal stem cell; C–H: Carbon
hydrogen mode; CM: Conditioned medium; DMEM: Dulbecco’s Modified
Eagle’s Medium; DPSC: Dental pulp stem cells; FBS: Fetal bovine serum;
KMCA: K-means cluster analysis; MCF-7: Michigan Cancer Foundation-7;
MSC: Mesenchymal stem cell; MTT: Methyl thiazolyl tetrazolium;
Nd:YAG: Neodymium-doped Yttrium Aluminum Garnet; PBS:
Phosphatebuffered saline; PTX: Paclitaxel; SD: Standard deviation; αMEM: Alpha
Modified Eagle’s Medium
The authors thank Dr Daniel Noel (IRMB) for providing bone marrow
mesenchymal stem cells. SA-A thanks the University of Jordan and Campus
France for her PhD grants.
No funding was received.
Availability of data and materials
Please contact the author for data requests.
HS carried out the Raman microscopy studies, participated in the data
analysis, and drafted the manuscript. SA-A carried out the cellular studies,
participated in the data and the statistical analysis, and drafted the manuscript.
EM contributed cellular culture and the isolation of DPSCs. CG participated in
the design of the study and proofreading. FC conceived, participated in the
design of and coordinated the work, and drafted the manuscript. VO participated
in specimen harvesting and drafted the manuscript. All authors read and approved
the final manuscript.
Ethics approval and consent to participate
Human wisdom teeth extracted for orthodontic reasons were recovered from
healthy patients (15–18 years old). Written informed consent was obtained from
the parents of the patients. This protocol was approved by the local ethical
committee (Comité de Protection des Personnes, Montpellier Hospital, France).
Consent for publication
Not applicable; our manuscript does not contain any individual person’s data.
The authors declare that they have no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in
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