Abstract:
Pancreatic Ductal Adenocarcinoma (PDA) and Hepatocellular Carcinoma (HCC) are
among the deadliest cancer types worldwide that are associated with arsenic intoxication.
Current drugs used in cancer management show a lot of side effects. There is, therefore, an
increased search for alternatives from medicinal plants with anticancer properties. Tridax
procumbens (TP) is a medicinal plant rich in antioxidant phytochemicals with little
information on its effects on cancer and arsenic toxicity. This study was designed to
investigate the effect of Tridax procumbens in PDA, HCC and arsenite-induced toxicity
using in vivo and in vitro models.
The TP was authenticated (UIH-22542), air-dried, blended, soaked in ethanol, and
concentrated to obtain the Crude Extract (CETP). The CETP was fractionated using
Hexane, Dichloromethane, and Ethyl Acetate to obtain Fractions (HXF, DCMF, and EAF,
respectively). Antioxidant assays of TP were performed. For in vivo study, 32 male Wistar
rats (80-100g) were assigned into four groups (n=8), and treated as follows; A (control); 1
ml/kg body weight olive oil, B; 2.5 mg/kg Sodium Arsenite (SA), C; 50 mg/kg CETP, D;
SA+CETP. Olive oil and CETP were administered once daily for 14 days, and SA twice
(days 7 and 14). Histological examination of lungs and brain, and micronucleated
Polychromatic Erythrocytes (mPCEs) frequency were carried out. The HCC and PDA cell
lines; HepG2 and Panc-1, were maintained in a humidified incubator, and treated with (10,
20, 50, 100, and 250 𝜇g/ml) dimethyl sulfoxide (control), CETP and CETP-fractions for
24 and 48 hours. Similarly, embryonic mouse pancreas (E11.5d) were cultured for five
days and treated with the test samples (20 𝜇g/ml) for two days. Cytotoxicity assays [3-
(4,5-dimethylyhiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), Live/Dead] were
carried out, and expression of proteins (cytokeratin-7, peanut agglutinin (PNA), α-
fetoprotein, insulin, glucagon, amylase, catalase, alkaline phosphatase, Glutathione Stransferase-pi (GST-pi), caspase-3, Bcl-2, Adenomatous Polyposis Coli (APC), p53,
p21Cip1/Wap-1, vimentin, Ki-67, Sox9, β-catenin, α1-antitrypsin, albumin, transferrin) were
evaluated using immunofluorescence. Data were analysed using descriptive statistics and
ANOVA at α0.05.
The DCMF scavenged 2,2-diphenyl-1-picrylhydrazyl hydrate and nitric oxide radicals
(IC50: 0.43 and 0.39 𝜇g/ml, respectively) relative to control (IC50: 0.85 and 0.14 𝜇g/ml,
respectively). The CETP reduced arsenite-induced histological lesions in lungs and brain,
and mPCEs [SA (21.00±3.33) to SA+CETP (3.80±0.58)] compared to control (0.60±0.40).
The DCMF elicited cell death (IC50=23.1 𝜇g/ml) compared to CETP (IC50=114.2 𝜇g/ml).
Relative to control, phenotype morphogenesis was observed in DCMF-treated embryonic
pancreas with immunopositivity for insulin, vimentin and amylase (1.3-fold), cytokeratin-
7 (1.5-fold), PNA (1.9-fold), and glucagon (2.8-fold). There were significant elevations in
transferrin (1.5-fold), albumin (1.8-fold), p53 (2.8-fold), caspase-3 (2.9-fold), catalase
(4.0-fold), p21Cip1/Wap-1 (4.4-fold), and alkaline phosphatase (5.0-fold) in DCMF-treated
cells compared to control. Conversely, there were significant reductions in β-catenin (1.3-
fold), α1-antitrypsin and cytokeratin-7 (2.0-fold), PNA and GST-pi (2.3-fold), α-
fetoprotein and Ki-67 (2.7-fold), and vimentin (10.8-fold) in DCMF-treated cells relative
to control. The DCMF induced Bcl-2 punctate nuclear staining, and cytoplasmic
translocation of APC, Sox9, and β-catenin in treated cells.
Leaf extract of Tridax procumbens exhibited antiproliferative activities via the decrease in
biomarkers of cancer induction and increase cellular antioxidant defence system.
