Flavonoids inhibit chronically exposed arsenic-induced proliferation and malignant transformation of HaCaT cells

MiR-96-5p Suppresses Progression of Arsenite-Induced Human Keratinocyte Proliferation and Malignant Transformation by Targeting Denticleless E3 Ubiquitin Protein Ligase Homolog

Long-term exposure to arsenic has been linked to a variety of cancers, among which skin cancer is the most prevalent form. However, the mechanism underlying arsenic carcinogenesis is unclear, and there is still limited information on the role of miRNAs in arsenic-induced skin cancer. This study aims to explore the role of miR-96-5p in the arsenite-induced proliferation and malignant transformation of human HaCaT keratinocytes. The GEO database (accession numbers GSE97303, GSE97305, and GSE97306) was used to extract mRNA and miRNA expression profiles of HaCaT cells treated with or without 0.1 μmol/L sodium arsenite for 3 and 7 weeks. In this paper, according to the CCK8 assay result, HaCaT cells exposed to 0.1 μmol/L sodium arsenite for 48 h were finalized. CCK8, MTT, EdU incorporation, and colony formation assays were used to determine the viability and proliferation of HaCaT cells and transformed HaCaT (T-HaCaT) cells. The subcellular localization and relative expression levels of DTL, as well as miR-96-5p in HaCaT cells induced by arsenite, were determined via immunofluorescence, RT-qPCR, and Western blot. Dual-luciferase reporter assay was performed to identify miR-96-5p bound directly to DTL. Transfection of miR-96-5p mimics or DTL siRNA was conducted to verify the arsenite-induced viability of HaCaT cells and T-HaCaT cells. T-HaCaT cells and nude mice were used to construct arsenite-induced malignant transformation and an in vivo xenograft model to demonstrate the over-expressed effect of miR-96-5p. The results showed that DTL was the target gene of miR-96-5p. Meanwhile, we also found that 0.1 μmol/L sodium arsenite upregulated DTL by decreasing the miR-96-5p level, leading to the proliferation and malignant transformation of HaCaT cells. MiR-96-5p agomir treatment slowed the growth of transplanted HaCaT cells transformed by arsenite in a manner associated with DTL downregulation in the nude mice xenograft model. Taken together, we confirmed that miR-96-5p, as a potent regulator of DTL, suppressed arsenite-induced HaCaT cell proliferation and malignant transformation, which might provide a novel therapeutic target for the treatment of arsenic-induced skin cancer.

Fabrication of Superparamagnetic Bimetallic Magnesium Nanoferrite Using Green Polyol: Characterization and Anticancer Analysis in Vitro on Lung Cancer Cell Line A549

Magnetic bimetallic nanoparticles find many industrial and clinical applications in the field of water treatment, antibacterial and anticancer activities. Therefore, the current article reports green synthesis using oleo-polyol as a surface modifier and synthesis agent for bimetallic magnetic magnesium ferrite nanoparticles. The role of hydroxyl functionality of castor oil (a natural polyol) on the enhancement of structural, morphological, magnetic, and particle size properties has also been discussed. These properties were characterized using FTIR, XRD spectroscopy, SEM, AFM, and TEM microscopy, Brunauer-Emmett-Teller (BET), and vibrating sample magnetometer (VSM) techniques. The effect of calcination temperatures (600-900 °C) on particle size (23-40 nm to 500-600 nm), crystallite sizes (73.15-292.67 nm), and saturation magnetization (20.87, 23.07, 32.39, and 33.13 emu g^-1) was analyzed. The influence of calcined temperatures on the anticancer activity of these nanoparticles has also been investigated in vitro using lung cancer cells (A549). Their biocompatibility, cytotoxicity, flow cytometry, and statistical analysis against lung cancer cells (A549) have been discussed. The green synthesis of magnesium nanoferrite particles using natural polyol and their application as anticancer agents against lung cancer cells (A549) have not been reported previously. They have exhibited far superior IC₅₀ values and anticancer activity as compared to other reported metal oxides and magnesium oxide nanoparticles.

Silibinin Radiosensitizes EGF Receptor-knockdown Prostate Cancer Cells by Attenuating DNA Repair Pathways

Emergence of radioresistance in prostate cancer (PCa) cells is a major obstacle in cancer therapy and contributes to the relapse of the disease. EGF receptor (EGFR) signaling plays an important role in the development of radioresistance. Herein, we have assessed the modulatory effects of silibinin on radiation-induced resistance via DNA repair pathways in EGFR-knockdown DU145 cells. shRNA-based silencing of EGFR was done in radioresistant human PCa DU145 cells and effects of ionizing radiation (IR) and silibinin were assessed using clonogenic and trypan blue assays. Furthermore, radiosensitizing effects of silibinin on PCa in context with EGFR were analyzed using flow cytometry, comet assay, and immunoblotting. Silibinin decreased the colony formation ability with an increased death of DU145 cells exposed to IR (5 Gray), with a concomitant decrease in Rad51 protein expression. Silibinin (25 μM) augmented the IR-induced cytotoxic effect in EGFR-knockdown PCa cells, along with induction of G2/M phase cell cycle arrest. Further, we studied homologous recombination (HR) and non-homologous end joining (NHEJ) pathways in silibinin-induced DNA double-strand breaks in EGFR-knockdown DU145 cells. Silibinin down-regulated the expression of Rad51 and DNA-dependent protein kinase proteins without any considerable effect on Ku70 and Ku80 in IR-exposed EGFR-knockdown PCa cells. The pro-survival signaling proteins, phospho-extracellular signal-regulated kinases (ERK)1/2, phospho-Akt and phospho-STAT3 were decreased by silibinin in EGFR-deficient PCa cells. These findings suggest a novel mechanism of silibinin-induced radiosensitization of PCa cells by targeting DNA repair pathways, HR and NHEJ, and suppressing the pro-survival signaling pathways, ERK1/2, Akt and STAT3, in EGFR-knockdown PCa cells.

KLF5-induced lncRNA IGFL2-AS1 promotes basal-like breast cancer cell growth and survival by upregulating the expression of IGFL1

Basal-like breast cancer (BLBC) is the most malignant subtype of breast cancer and has a poor prognosis. Kruppel-like factor 5 (KLF5) is an oncogenic transcription factor in BLBCs. The mechanism by which KLF5 promotes BLBC by regulating the transcription of lncRNAs has not been fully elucidated. In this study, we discovered that lncRNA IGFL2-AS1 is a downstream target gene of KLF5 and that IGFL2-AS1 mediates the pro-proliferation and pro-survival functions of KLF5. Additionally, we demonstrated that IGFL2-AS1 functions by upregulating the transcription of its neighboring gene IGFL1 via two independent mechanisms. On the one hand, nuclear IGFL2-AS1 promotes the formation of a KLF5/TEAD4 transcriptional complex at the IGFL1 gene enhancer. On the other hand, cytoplasmic IGFL2-AS1 inhibits the expression of miR4795-3p, which targets the IGFL1 gene. TNFα induces the expression of IGFL2-AS1 and IGFL1 through KLF5. Taken together, the results of this study indicate that IGFL2-AS1 and IGFL1 may serve as new therapeutic targets for BLBCs.

Mancozeb selectively induces mitochondrial-mediated apoptosis in human gastric carcinoma cells through ROS generation

Mancozeb (Manganese ethylene bis-dithiocarbamate with zinc salt) is a dithiocarbamate fungicide used to control fungal disease in many fruit plants, flowers and the maintenance of field crops. The effect of mancozeb on cell viability of human gastric adenocarcinoma AGS, SNU-1 cells and human normal FHs 74 Int cells were investigated. This study demonstrated that mancozeb was able to inhibit cell proliferation by 56-82% at 5-10 μM concentrations after 48 h. Mancozeb treatment for 48 h resulted in 33% (P < 0.05) and 61% (P < 0.001) increase in apoptotic cells at 5 and 10 μM concentrations in AGS cells, respectively. Treatment with mancozeb did not cause cell cycle arrest, while modulated the expression level of cleaved caspase-3, and cleavage of poly-(ADP-ribose) polymerase. Furthermore, treatment with mancozeb caused a rapid stimulation of reactive oxygen species (ROS) and loss of mitochondrial transmembrane potential. The results also showed that mancozeb-induced apoptosis was accompanied by up-regulation of Bax and down-regulation of Bcl-2 and Bcl-xL. Overall, our data suggested that mancozeb caused ROS generation which induced significant (P < 0.05) apoptosis in AGS cells that was attenuated with pretreatment of NAC. More importantly, same concentration of mancozeb did not show any considerable effect on cell growth, death, cell cycle arrest and ROS generation in normal FHs 74 Int cells. Overall, for the first time these results suggest that mancozeb has selective anticancer activity at lower concentrations against gastric cancer cells.

Plumbagin induces ROS-mediated apoptosis and cell cycle arrest and inhibits EMT in human cervical carcinoma cells

Plumbagin, an important phytochemical from the roots of the medicinal plant Plumbago zeylanica L. has shown many biological activities. The roots of this plant have been in use in the Indian system of medicine for more than twenty five centuries for treatments of various ailments. It has shown anticancer activities, however, the anticancer and anti-metastatic effects of plumbagin are largely unknown against cervical cancer cells. Herein, we investigated the molecular alterations associated with plumbagin-mediated inhibition of growth, survival and epithelial to mesenchymal transition of human cervical cancer SiHa and HeLa cells. Plumbagin (1–4 μM) caused a significant decrease in the cell viability and increased the cell death in SiHa and Hela cells after 24 and 48 h. Plumbagin also caused strong G2/M and S-G2/M phase cell cycle arrest in SiHa and HeLa cells, respectively which was accompanied by a decrease in the expression of cyclin and CDK levels. The expression levels of both mRNAs and proteins of cyclin B1, A and E2 and CDK 1 and 2 decreased after 24 and 48 h. Plumbagin strongly induced apoptosis along with increased ratio of Bax : Bcl2 and cleavage of caspase 3, 9, and PARP. Plumbagin caused a significant increase in reactive oxygen species generation which mediated cell death as it was attenuated by pre-treatment with N-acetyl cysteine. Additionally, we also report for the first time that plumbagin possesses an anti-metastatic effect at non-cytotoxic doses that was accompanied by the modulation of MMP-2, 9, E-cadherin, N-cadherin, β-catenin and vimentin. Taken together, our findings suggest that plumbagin has strong anticancer and anti-metastatic effects against human cervical cancer cells.

Proposed mechanism of action of plumbagin in human cervical carcinoma SiHa and HeLa cells.