Piperlongumine inhibits antioxidant enzymes, increases ROS levels, induces DNA damage and G2/M cell cycle arrest in breast cell lines.

Piperlongumine (PLN) is a biologically active alkaloid/amide derived from Piper longum, with known promising anticancer activity. The aim of this study was to compare the antiproliferative activity of PLN in human breast MCF-7 adenocarcinoma cell line with effects in HB4a normal mammary epithelial non-tumor cell line. The parameters examined were cell growth, viability, reactive oxygen species (ROS) levels and DNA damage, as well as the effects on the modulating targets responsible through regulation of these pathways. PLN increased ROS levels and expression of the SOD1 antioxidant enzyme. PLN inhibited the expression of the antioxidant enzymes catalase, TRx1, and PRx2. The ability of PLN to inhibit antioxidant enzyme expression was associated with the oxidative stress response. PLN induced genotoxicity in both cell lines and upregulated the levels of GADD45A mRNA and p21 protein. The DNA damage response ATR protein was downregulated in both cell lines and contributed to an enhanced PLN genotoxicity. In HB4a cells, Chk1 protein, and mRNA levels were also decreased. In response to elevated ROS levels and DNA damage induction, the cells were arrested at the G2/M phase, probably in an attempt to promote cell survival. Although cell viability was reduced in both cell lines, only HB4a cells underwent apoptotic cell death, whereas other types of cellular death may be involved in MCF-7 cells. Taken together, these data provide insight into the anticancer mechanisms attributed to PLN effects, which acts as an inhibitor of DNA damage response (DDR) proteins and antioxidant enzymes.

Cytokines as an important player in the context of CAR-T cell therapy for cancer: Their role in tumor immunomodulation, manufacture, and clinical implications.

CAR-T cell therapies have been recognized as one of the most advanced and efficient strategies to treat patients with hematologic malignancies. However, similar results have not been observed for the treatment of solid tumors. One of the explanations is the fact that tumors have extremely hostile microenvironments for the infiltration and effector activity of T-cells, mainly due to the presence of highly suppressive cytokines, hypoxia, and reactive oxygen species. Taking advantage of cytokines functionally, new fourth-generation CAR constructs have been developed to target tumor cells and additionally release cytokines that can contribute to the cytotoxicity of T-cells. The manufacturing process, including the use of cytokines in the expansion and differentiation of T cells, is also discussed. Finally, the clinical aspects and the influence of cytokines on the clinical condition of patients, such as cytokine release syndrome, who receive treatment with CAR-T cells are addressed. Therefore, this review aims to highlight how important cytokines are as one of the major players of cell therapy.

Dimethoxycurcumin reduces proliferation and induces apoptosis in renal tumor cells more efficiently than demethoxycurcumin and curcumin.

Curcumin (Cur), is a pigment with antiproliferative activity but has some pharmacokinetic limitations, which led researchers to look for more effective structure analogs. This work investigated the effects of Cur and compared them with the two analogs, demethoxycurcumin (DeMC) and dimethoxycurcumin (DiMC), to elucidate their mechanisms of action. The cytotoxic, antiproliferative, and genotoxic effects these compounds were correlated based on gene expression analysis in the human renal adenocarcinoma cells (786-O). Cur decreased CYP2D6 expression and exhibited cytotoxic effects, such as inducing monopolar spindle formation and mitotic arrest mediated by the increase in CDKN1A (p21) mRNA. This dysregulation induced cell death through a caspase-independent pathway but was mediated by decrease in MTOR and BCL2 mRNA expression, suggesting that apoptosis occurred by autophagy. DeMC and DiMC had similar effects in that they induced monopolar spindle and mitotic arrest, were genotoxic, and activated GADD45A, an important molecule in repair mechanisms, and CDKN1A. However, the induction of apoptosis by DeMC was delayed and regulated by the decrease of antiapoptotic mRNA BCL.XL and subsequent activation of caspase 9 and caspase 3/7. DiMC treatment increased the expression of CYP1A2, CYP2C19, and CYP3A4 and exhibited higher cytotoxicity compared with other compounds. It induced apoptosis by increasing mRNA expression of BBC3, MYC, and CASP7 and activation of caspase 9 and caspase 3/7. These data revealed that different gene regulation processes are involved in cell death induced by Cur, DeMC, and DiMC. All three can be considered as promising chemotherapy candidates, with DiMC showing the greatest potency.

Carnosic acid exhibits antiproliferative and proapoptotic effects in tumoral NCI-H460 and nontumoral IMR-90 lung cells.

Carnosic acid (CA) is a phenolic diterpene with many important biological activities including antimicrobial, antioxidant, anti-inflammatory properties, and anti-proliferative properties. The aim of the present study was to investigate cytotoxic activity, cell cycle, apoptotic, and molecular effects attributed to CA in non-tumoral IMR-90 (human fetal lung fibroblasts), as well as tumoral NCI-H460 (human non-small-cell lung cancer) cell lines. Cell proliferation was evaluated by Real-Time Cell Analysis system, while apoptosis and cell cycle were assessed using flow cytometry. RT-qPCR was used to estimate the relative expression of genes involved in cell cycle regulation, DNA damage and repair, and apoptosis induction. CA inhibited proliferation of IMR-90 and NCI-H460 cells via cell cycle arrest at G0/G1 and G2/M phases, according to the treatment concentration. The mRNA levels of genes encoding cyclins A2, B1, and B2 were downregulated in response to CA treatment of IMR-90 cells. Apoptosis was induced and proapoptotic gene PUMA was upregulated in both cell lines. mRNA levels of genes ATR, CCND1, CHK1, CHK2, MYC, GADD45A, H2AFX, MTOR, TP53, and BCL2, CASP3 were not markedly changed following CA treatments. Although CA exerted antiproliferative activity against NCI-H460 tumor cells, this phytochemical induced toxic effects in non-tumoral cells, and thus needs to be considered carefully prior to pharmacological use therapeutically.

Focused screening reveals functional effects of microRNAs differentially expressed in colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is still a leading cause of death worldwide. Recent studies have pointed to an important role of microRNAs in carcinogenesis. Several microRNAs are described as aberrantly expressed in CRC tissues and in the serum of patients. However, functional outcomes of microRNA aberrant expression still need to be explored at the cellular level. Here, we aimed to investigate the effects of microRNAs aberrantly expressed in CRC samples in the proliferation and cell death of a CRC cell line. METHODS: We transfected 31 microRNA mimics into HCT116 cells. Total number of live propidium iodide negative (PI-) and dead (PI+) cells were measured 4 days post-transfection by using a high content screening (HCS) approach. HCS was further used to evaluate apoptosis (via Annexin V and PI staining), and to discern between intrinsic and extrinsic apoptotic pathways, by detecting cleaved Caspase 9 and 8, respectively. To reveal mRNA targets and potentially involved mechanisms, we performed microarray gene expression and functional pathway enrichment analysis. Quantitative PCR and western blot were used to validate potential mRNA targets. RESULTS: Twenty microRNAs altered the proliferation of HCT116 cells in comparison to control. miR-22-3p, miR-24-3p, and miR-101-3p significantly repressed cell proliferation and induced cell death. Interestingly, all anti-proliferative microRNAs in our study had been previously described as poorly expressed in the CRC samples. Predicted miR-101-3p targets that were also downregulated by in our microarray were enriched for genes associated with Wnt and cancer pathways, including MCL-1, a member of the BCL-2 family, involved in apoptosis. Interestingly, miR-101-3p preferentially downregulated the long anti-apoptotic MCL-1 L isoform, and reduced cell survival specifically by activating the intrinsic apoptosis pathway. Moreover, miR-101-3p also downregulated IL6ST, STAT3A/B, and MYC mRNA levels, genes associated with stemness properties of CRC cells. CONCLUSIONS: microRNAs upregulated in CRC tend to induce proliferation in vitro, whereas microRNAs poorly expressed in CRC halt proliferation and induce cell death. We provide novel evidence linking preferential inhibition of the anti-apoptotic MCL-1 L isoform by miR-101-3p and consequent activation of the intrinsic apoptotic pathway as potential mechanisms for its antitumoral activity, likely due to the inhibition of the IL-6/JAK/STAT signaling pathway.

A High-Content Screening Approach to Identify MicroRNAs Against Head and Neck Cancer Cell Survival and EMT in an Inflammatory Microenvironment.

Head and neck squamous cell carcinoma (HNSCC) is among the most common cancer types. Metastasis, the main cause of death by cancer, can be promoted by an inflammatory microenvironment, which induces epithelial-mesenchymal transition (EMT) through a NF-κB-mediated stabilization of Snail. Here, we aimed to explore how microRNAs (miRs) can affect cell survival and EMT in HNSCC cells under an inflammatory microenvironment. By using a high-content screening (HCS) approach, we evaluated alterations in morphometric parameters, as well as expression/localization of Snail/Slug, in HNSCC cells primed with TNF-α. Based on those quantitation, we established the optimal experimental conditions of EMT induction driven by TNF-α. Those conditions were applied to cells transfected with distinct miRs (N = 31), followed by clusterization of miRs based on alterations related to cell survival and EMT. The signaling pathways enriched with molecular targets from each group of miRs were identified by in silico analyses. Finally, cells were transfected with siRNAs against signaling pathways targeted by miRs with anti-survival/EMT effect and evaluated for alterations in cell survival and EMT. Overall, we observed that TNF-α, at 20 ng/ml, induced EMT-related changes in cell morphology, Snail/Slug expression, and cell migration. Predicted targets of miRs with anti-survival/EMT effect were enriched with targets of NF-κB, PI3K/ATK, and Wnt/beta catenin pathways. Strikingly, individual gene silencing of elements from those pathways, namely RELA (NF-kB), AKT1 (PI3K/AKT), and CTNNB1 (Wnt/beta catenin) reduced cell survival and/or expression of Snail/Slug in cells stimulated with TNF-α. As a whole, our HCS approach allowed for the identification of miRs capable of inhibiting cell survival and EMT considering the presence of an inflammatory microenvironment, also indicating the common signaling pathways and molecular targets most likely to underlie those alterations. These findings may contribute to the development of targeted therapies against HNSCC.

Mitotic spindle defects and DNA damage induced by dimethoxycurcumin lead to an intrinsic apoptosis pathway in HepG2/C3A cells.

Dimethoxycurcumin (DiMC), a synthetic analog of curcumin, was shown to have antiproliferative activity in human tumor cell lines. Therefore, we investigated its cytotoxic, antiproliferative, genotoxic, and apoptotic effect and correlated these evaluations with the expression of transcripts and proteins in the human hepatocellular carcinoma cell line (HepG2/C3A). Treatment with DiMC resulted in increased CYP2E1, CYP2C19 and CYP1A2 transcripts levels and was cytotoxic (≥10 µM). DiMC caused mitotic arrest by inducing monopolar spindle formation and was genotoxic increasing expression of the CDKN1A, GADD45A and PARP1 gene, key effectors in the cell cycle arrest and DNA repair pathways, respectively. This genotoxicity was caused by generation of reactive oxygen species and reduction of antioxidant proteins levels. Furthermore, we observed a decrease in important proteins involved in DNA repair. In addition to the observed apoptotic morphology and the presence of annexin labeling, we observed increased expression of BAK1 and CASP7 genes and caspase 3/7 protein activity, showing that these effects caused apoptosis through the intrinsic pathway in HepG2/C3A cells. Our results indicate that DiMC modulates important molecular targets leading to cell death even in metabolic competent cells models has considerable potential in anticancer therapy.

Molecular pathways related to the control of proliferation and cell death in 786-O cells treated with plumbagin.

Plumbagin (PLB) is a phytochemical being used for centuries in traditional medicines. Recently, its capacity to inhibit the development of human tumors has been observed, through the induction of apoptosis, cell cycle arrest, and inhibition of angiogenesis and metastasis. Here we evaluated the mechanism of action of PLB in the kidney adenocarcinoma 786-O cell line, which are metabolizing cells important for toxicology studies. After the treatment with PLB, we observed increased apoptosis and cell cycle arrest in S and G2/M phases, starting at 5 µM. In addition, PLB was cytotoxic, genotoxic and induced loss of cell membrane integrity. Regarding gene expression, treatment with 7.5 µM PLB reduced the amount of MTOR, BCL2 and ATM transcripts, and increased CDKN1A (p21) transcripts. Phosphorylation levels of yH2AX was increased and MDM2 protein level was reduced following the treatment with PLB, demonstrating its genotoxic effect. Our results suggest that PLB acts in molecular pathways related to the control of proliferation and cell death in 786-O cells.

High-content screen in human pluripotent cells identifies miRNA-regulated pathways controlling pluripotency and differentiation.

BACKGROUND: By post-transcriptionally regulating multiple target transcripts, microRNAs (miRNAs or miR) play important biological functions. H1 embryonic stem cells (hESCs) and NTera-2 embryonal carcinoma cells (ECCs) are two of the most widely used human pluripotent model cell lines, sharing several characteristics, including the expression of miRNAs associated to the pluripotent state or with differentiation. However, how each of these miRNAs functionally impacts the biological properties of these cells has not been systematically evaluated. METHODS: We investigated the effects of 31 miRNAs on NTera-2 and H1 hESCs, by transfecting miRNA mimics. Following 3-4 days of culture, cells were stained for the pluripotency marker OCT4 and the G2 cell-cycle marker Cyclin B1, and nuclei and cytoplasm were co-stained with Hoechst and Cell Mask Blue, respectively. By using automated quantitative fluorescence microscopy (i.e., high-content screening (HCS)), we obtained several morphological and marker intensity measurements, in both cell compartments, allowing the generation of a multiparametric miR-induced phenotypic profile describing changes related to proliferation, cell cycle, pluripotency, and differentiation. RESULTS: Despite the overall similarities between both cell types, some miRNAs elicited cell-specific effects, while some related miRNAs induced contrasting effects in the same cell. By identifying transcripts predicted to be commonly targeted by miRNAs inducing similar effects (profiles grouped by hierarchical clustering), we were able to uncover potentially modulated signaling pathways and biological processes, likely mediating the effects of the microRNAs on the distinct groups identified. Specifically, we show that miR-363 contributes to pluripotency maintenance, at least in part, by targeting NOTCH1 and PSEN1 and inhibiting Notch-induced differentiation, a mechanism that could be implicated in naïve and primed pluripotent states. CONCLUSIONS: We present the first multiparametric high-content microRNA functional screening in human pluripotent cells. Integration of this type of data with similar data obtained from siRNA screenings (using the same HCS assay) could provide a large-scale functional approach to identify and validate microRNA-mediated regulatory mechanisms controlling pluripotency and differentiation.

Response of HepG2/C3A cells supplemented with sodium selenite to hydrogen peroxide-induced oxidative stress.

Oxidative stress (OS) is involved in the onset of various pathological processes, and sodium selenite (Na2SeO3) is known to have antioxidant activity. This study evaluated the cellular response of human HepG2/C3A cells supplemented with Na2SeO3 when exposed to hydrogen peroxide (H2O2)-induced OS. We analyzed cytotoxicity, cell proliferation, and genotoxicity in comparison with molecular data of mRNA and protein expression. The MTT and comet assays revealed that Na2SeO3 conferred cytoprotective and anti-genotoxic effects. In contrast, RTCA (Real-Time Cell Analysis) and flow cytometry analysis revealed that Na2SeO3 did not inhibit H2O2-induced anti-proliferative effects or cell cycle arrest (G2/M). Cells exposed simultaneously to Na2SeO3 and H2O2 showed overexpression of GPX1 mRNA, indicating that Na2SeO3 influenced the cellular antioxidant system. Furthermore, downregulation of CAT mRNA and SOD1 and PRX2 proteins induced by H2O2, was minimal after the Na2SeO3+H2O2 treatment. Although normalization of CCN2B mRNA expression by Na2SeO3 was observed after the Na2SeO3+H2O2 treatment, this was not observed for other genes such as CDKN1A, CDKN1C, and CDKN2B, which are related to cell cycle control, nor for GADD45A, which is involved in the cellular response to DNA damage. Furthermore, both CDKN1B and CDKN1C expression were downregulated in HepG2/C3A cells treated with Na2SeO3 only. Our results indicate that cellular response to Na2SeO3 involved the modulation of the antioxidant system. Na2SeO3 was unable completely recover HepG2/C3A cells from H2O2-induced oxidative damage, as evidenced by analysis of cell proliferation kinetics, cell cycle assay, and expression of key genes involved in cell cycle progression and response to DNA damage.

Identification of Long Noncoding RNAs Deregulated in Papillary Thyroid Cancer and Correlated with BRAFV600E Mutation by Bioinformatics Integrative Analysis.

Papillary Thyroid Cancer (PTC) is an endocrine malignancy in which BRAFV600E oncogenic mutation induces the most aggressive phenotype. In this way, considering that lncRNAs are arising as key players in oncogenesis, it is of high interest the identification of BRAFV600E-associated long noncoding RNAs, which can provide possible candidates for secondary mechanisms of BRAF-induced malignancy in PTC. In this study, we identified differentially expressed lncRNAs correlated with BRAFV600E in PTC and, also, extended the cohort of paired normal and PTC samples to more accurately identify differentially expressed lncRNAs between these conditions. Indirectly validated targets of the differentially expressed lncRNAs in PTC compared to matched normal samples demonstrated an involvement in surface receptors responsible for signal transduction and cell adhesion, as well as, regulation of cell death, proliferation and apoptosis. Targets of BRAFV600E-correlated lncRNAs are mainly involved in calcium signaling pathway, ECM-receptor interaction and MAPK pathway. In summary, our study provides candidate lncRNAs that can be either used for future studies related to diagnosis/prognosis or as targets for PTC management.

Cis-Nerolidol Induces Endoplasmic Reticulum Stress and Cell Death in Human Hepatocellular Carcinoma Cells through Extensive CYP2C19 and CYP1A2 Oxidation.

Of late, many studies are attempting to find new molecules with anticancer properties, especially those with the capability to inhibit cell growth. The aim of this work was to evaluate nerolidol, a plant-based compound, as its cytotoxicity, genotoxicity, antiproliferative and apoptotic induction, cell cycle, mitochondrial membrane potential and RT-qPCR of transcripts related to those pathways in the human hepatocellular carcinoma cell line (HepG2/C3A). Only cis-nerolidol (C-NER) demonstrated cytotoxicity (100-250 µM) activity and was selected to conduct the following experiments. C-NER did not show genotoxic activity, but altered the mitochondrial membrane potential, reduced cell proliferation by arresting cell cycle in G1 phase and induced cell death. RT-qPCR showed that C-NER down-regulated genes related to apoptosis (BAK1, BAX, CAPN1, CASP8, CASP9, PARP1 and TP53), cell cycle (CCND1, CCNE1, CDK1 and CDK2), xenobiotic metabolism (CYP2D6 and CYP3A4) and paraptosis (IGF1R receptor). Up-regulation was seen in case of genes related to cell survival (BBC3 and MYC) and reticulum stress protein response (EIF2AK3 and ERN1) and xenobiotic metabolism (CYP1A2 and CYP2C19). We deduced that the antiproliferative activity of C-NER is attributable to its modulation of the cyclins and cyclin-dependent kinases as these proteins are necessary for G1/S phase transition. EIF2AK3, ERN1, CYP2C19 and CYP1A2 up-regulation suggests that endoplasmic reticulum stress was induced owing to the increased activity of cytochrome P450 enzymes. Caspase-independent cell death was also observed, indicating that another type of cell death, paraptosis, was triggered. Our results indicate that C-NER has considerable potential in anticancer therapy because it modulates important molecular targets of cell survival and proliferation.