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.

Cellular and molecular antiproliferative effects in 2D monolayer and 3D-cultivated HT-29 cells treated with zerumbone.

Zerumbone (ZER) is a phytochemical isolated from plants of the Zingiberaceae family. Numerous studies have demonstrated its diverse pharmacological properties, particularly its potent antitumorigenic activity. This study aimed to assess the antiproliferative effects of ZER on HT-29 cells cultivated in both two-dimensional (2D) monolayer and three-dimensional (3D) spheroid culture systems. The evaluation of growth (size), cell death, and cell cycle arrest in 3D spheroid HT-29 cells was correlated with mRNA expression data. Treatment of 2D cells revealed that ZER exhibited cytotoxicity at concentrations above 30 µM, and an IC50 of 83.54 µM (24-h post-ZER treatment) effectively suppressed cell migration. In the 3D model, ZER induced an increase in spheroid volume over a 72-h period attributed to disaggregation and reconfiguration of characteristic zones. Analysis of cell death demonstrated a significant rise in apoptotic cells after 24 h of ZER treatment, along with cell cycle arrest in the G1 phase. Furthermore, ZER treatment resulted in alterations in mRNA expression, affecting key signaling pathways involved in cell death (BCL2 and BBC3), endoplasmic reticulum stress (ERN1), DNA damage (GADD45A), cell cycle regulation (CDKN1A, NFKB1, MYC, and TP53), and autophagy (BECN1 and SQSTM1). These findings suggested that ZER holds promise as a potential candidate for the development of novel anticancer agents that can modulate crucial cell signaling pathways. Additionally, the use of the 3D culture system proved to be a valuable tool in our investigation.

Disruption of caspase-independent cell proliferation pathway on spheroids (HeLa cells) treated with curcumin.

Curcumin is an antiproliferative phytochemical extracted from Curcuma longa L and which has been studied in preclinical drug screening using cell monolayers and animal models. However, several limitations of these culture systems may be overcome by performing screening with three-dimensional (3-D) cell culture. The aim of this study was to investigate the effects of curcumin on cytotoxicity and genotoxicity as well as spheroid growth using cervical adenocarcinoma HeLa cell spheroids by performing RT-PCR mRNA expression of genes involved in cell death (CASP3, CASP8, CASP9, PARP1, BBC3, BIRC5, BCL2, TNF), autophagy (BECN1, SQSTM1), cell cycle regulation (TP53, C-MYC, NF-kB, CDKN1A, m-TOR, TRAF-2), DNA damage repair (H2AFX, GADD45A, GADD45G), oxidative stress (GPX1), reticulum stress (EIF2AK3, ERN1), and invasion (MMP1, MMP9) was investigated. Curcumin was cytotoxic in a concentration-dependent manner. Curcumin-treated spheroids exhibited lower proliferative recovery and cell proliferation attenuation, as observed in the clonogenic assay. Further, no marked genotoxicity was detected. Curcumin-treated spheroids displayed reduced expression of BECN1 (2.9×), CASP9 (2.1×), and PARP1 (2.1×) mRNA. PARP1 inhibition suggested disruption of essential pathways of proliferation maintenance. Downregulated expression of CASP9 mRNA and unchanged expression of CASP3/8 mRNA suggested caspase-independent cell death, whereas downregulated expression of BECN1 mRNA indicated autophagic disruption. Therefore, curcumin exhibits the potential for drug development with antiproliferative activity to be considered for use in cancers.

DNA damage and reticular stress in cytotoxicity and oncotic cell death of MCF-7 cells treated with fluopsin C.

Fluopsin C is an antibiotic compound derived from secondary metabolism of different microorganisms, which possesses antitumor, antibacterial, and antifungal activity. Related to fluopsin C antiproliferative activity, the aim of this study was to examine the following parameters: cytotoxicity, genotoxicity, cell cycle arrest, cell death induction (apoptosis), mitochondrial membrane potential (MMP), colony formation, and mRNA expression of genes involved in adaptive stress responses and cellular death utilizing a monolayer. In addition, a three-dimensional cell culture was used to evaluate the effects on growth of tumor spheroids. Fluopsin C was cytotoxic (1) producing cell division arrest in the G1 phase, (2) elevating expression of mRNA of the CDKN1A gene and (3) decrease in expression of mRNA H2AFX gene. Further, fluopsin C enhanced DNA damage as evidenced by increased expression of mRNA of GADD45A and GPX1 genes, indicating that reactive oxygen species (ROS) may be involved in the observed genotoxic response. Reticulum stress was also detected as noted from activation of the ribonuclease inositol-requiring protein 1 (IRE1) pathway, since a rise in mRNA expression of the ERN1 and TRAF2 genes was observed. During the cell death process, an increase in mRNA expression of the BBC3 gene was noted, indicating participation of this antibiotic in oncotic (ischemic) cell death. Data thus demonstrated for the first time that fluopsin C interferes with the volume of tumor spheroids, in order to attenuate their growth. Our findings show that fluopsin C modulates essential molecular processes in response to stress and cell death.

Diosgenin increases BBC3 expression in HepG2/C3A cells and alters cell communication in a 3D spheroid model.

Preclinical studies have shown that diosgenin, a steroidal sapogenin, is a promising phytochemical for treating different pathological conditions, such as cancer, diabetes, and cardiovascular diseases. However, the toxicological safety of this molecule for therapeutic use in humans needs to be better understood. Thus, this study aimed to evaluate the mechanisms of action of diosgenin in HepG2/C3A human hepatocellular carcinoma cells. Cytotoxicity, genotoxicity, alterations in the cell cycle, and cell death (apoptosis) were investigated and associated with the gene expression profile of pathways involved in these processes. The effects of diosgenin on the growth of spheroids were also tested. Diosgenin induced a dose-dependent reduction in cell viability and cell cycle arrest in S and G2/M phases and apoptosis in response to DNA damage. Apoptosis was associated with an increase in the expression of BBC3, a participant in the intrinsic apoptosis pathway. Diosgenin also promoted an increase in volume and greater cellular breakdown in spheroids. These results allowed a better understanding of the toxicity of diosgenin in human cells and contributed to the development of treatments based on this phytochemical.

Effects of ß-glucan from S. cerevisiae on the expression of Casp9, Ccna2 and Sod1 genes in MCF-7 cells

ß-Glucans (ßG) are polysaccharides widely distributed in nature with chemopreventive properties. The aim of this study was to investigate the effects of ßG and the combined treatment with doxorubicin (Dox) on cell viability and mRNA levels of genes involved in cell cycle, apoptosis and antioxidant response. ßG was not cytotoxic. The mRNA levels of CCNA2of cells exposed to ß-glucan was upregulated and the exposure to Dox decreased the expression, while the combination led to an upregulation. Modulation of mRNA levels of CASP9suggest that ßG could inhibit promotion and progression steps of carcinogenesis, eliminatingneoplastic cells. The upregulation of CCNA2gene in combined treatment could be occurred due to ability of ßG in restoring the cell cycle distribution pattern after treatment with Dox. The upregulation of SOD1suggests that ßG can enhance the intracellular antioxidant defense, reducing the levels of superoxide dismutase induced by Dox. This response could reduce oxidative damage and attenuate tissue damage during chemotherapeutic treatment. Our data suggest that the drug combination may be less effective in killing tumor cells than the treatment with Dox alone. Thus, future studies should carefully consider this effect on indication of ßG during chemotherapy.Keywords:caspase-9; cyclin A2; superoxide dismutase 1; cell cycle; antioxidant.Received on July 2, 2020.Accepted on February 7, 2022.IntroductionGlucans are polysaccharides widely distributed in nature and oftenstudied due to chemopreventive properties. They are constituent of the cell wall of plants (oats and barley), algae, bacteria and fungi. ß-glucans (ßG)have a common structure comprising a main chain of ß-(1,3) and/or ß-(1,4) D-glucopyranosyl unit and they differ in length and branching structures. ßG of Saccharomyces cerevisiaehave 1→6 side branches while those of bacteria have 1→4 side branches (Chan, Chan, & Sze, 2009). ßGcan prevent DNA damage induced by chemical and physical agents (Ghavami,Goliaei, Taghizadeh, & Nikoofar, 2014). Some authors showed its significant efficacy in preventing mutagenic effects caused by doxorubicin, cyclophosphamide and cisplatin (Tohamy, El-Ghor, El-Nahas, & Noshy, 2003), methyl methanesulfonate (Oliveira et al., 2007)and hydrogen peroxide (Slamenová, 2003). Moreover, some studies have related the antioxidant ability of ßGagainst reactive free radicals formed by endogenous metabolic processes or exogenous chemicals (Tsiapali et al., 2001; Slamenová,2003; Sener, Eksioglu-Demiralp, Cetiner, Ercan, & Yegen, 2006; Guerra Dore et al., 2007; Kofuji et al., 2012; Lei et al., 2015). Yeast-derived ßGhave modulating action of humoral and cellular immune responses (Vetvicka et al., 2007).This activity provides protection to the organism against infections and cancer development (Samuelsen, Schrezenmeir, & Knutsen, 2014; Roudbary, Daneshmand, Hajimorad, Roudbarmohammadip, & Hassan, 2015). Despite postulated modes of action by which ß-glucan works are lacking information about the molecular mechanisms involved in the chemopreventive activity of this polysaccharide. In addition, compounds with chemopreventive properties can contribute to reduce side effects and toxicity during the chemotherapeutic treatment. Therefore, the aim of this study was to investigate the effects of ßG and the combined treatment with doxorubicin (Dox) on the expression of genes related with apoptosis (CASP9), cell cycle control (CCNA2)and antioxidant defense (SOD1)in human breast cancer MCF-7 cells. Doxorubicin (Dox) was chosen because it is one of the most used chemotherapeutic agent for cancer treatment. The limitation on the use of Dox in cancer treatment is the lack of selectivity against cancer cells and, consequently, its toxicity to patients.(AU)

Up and down-regulation of mRNA in the cytotoxicity and genotoxicity of Plumbagin in HepG2/C3A.

Studies that evaluated the mechanisms of action of Plumbagin (PLB) and its toxicity may contribute to future therapeutic applications of this compound. We investigate biomarker important in the mechanisms of action correlate the expression of mRNA with the cytotoxic and genotoxic effects of PLB on HepG2/C3A. In the analysis of cytotoxicity, PLB decreased cell viability and membrane integrity at concentrations ≥ 15µM. Xenobiotic-metabolizing system showed strong mRNA induction of CYP1A1, CYP1A2, and CYP3A4, suggesting extensive metabolization. PLB induced apoptosis and an increase in the mRNA expression of genes BBC3, CASP3, and CASP8. At a concentration of 15µM, there was a reduction in the expression of PARP1 mRNA and an increase in the expression of BECN1 mRNA, suggesting that PLB may also induce cell death by autophagy. PLB induced an arrest at the G2/M phase due to DNA damage, as observed in the comet assay. This damage is associated with the increased mRNA expression of genes p21, GADD45A, and H2AFX and with changes in the expression of proteins H2AX, p21, p53, Chk1, and Chk2. These results allow a better understanding of the cellular action of PLB and of its toxicity, thereby contributing to the development of PLB-based drugs, with markers of mRNA expression possibly playing a role as indicators for monitoring toxicity in human cells.

The α -Tomatine Exhibits Antiproliferative Activity, Rupture of Cell Membranes and Induces the Expression of APC Gene in the Human Colorectal Adenocarcinoma Cell Line (Ht-29)

Abstract The α-tomatine is a steroidal glycoalkaloid found in immature tomatoes (Lycopersicon esculentum) that has important biological functions including the inhibition of cancer cell growth and preventing metastasis. This study aimed to evaluate the effects of α-tomatine on cytotoxicity, cellular proliferation, apoptosis, and mRNA expression of APC, CCNA2, β-catenin, CASP9, BAK, BAX and BCL-XL in colorectal adenocarcinoma cell line HT-29. HT29 cells were treated with three concentrations of α-tomatine (0.1, 1 and 10 µg/mL), although only the 1 µg/mL concentration of α-tomatine was used to evaluate genetic expression patterns by real time-PCR. Results showed that α-tomatine was cytotoxic only at the 10 µg/mL concentration. Cell proliferation was significantly inhibited after the first 24 hours of treatment only with concentrations of 10 µg/mL. In contrast, there were no significant differences in apoptosis for any treatment. In the gene expression studies, only APC expression was significantly altered by α-tomatine treatment. In conclusion, α-tomatine has antiproliferative activity in the first 24h of treatment, does not induce apoptosis in this cell line and causes disruption of cell membranes, thereby increasing the expression of APC gene related to cell cycle.

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.

Genistein Affects Expression of Cytochrome P450 (CYP450) Genes in Hepatocellular Carcinoma (HEPG2/C3A) Cell Line.

BACKGROUND: Genistein (5,7-Dihydroxy-3-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) is the most abundant isoflavone in soybean, which has been associated with a lower risk of development of cancer and cardiovascular diseases. Of particular interest regarding cancer preventive properties of flavonoids is their interaction with cytochrome P450 enzymes (CYPs). However, contradictory data report the effect of genistein on expression of СYPs enzymes. OBJECTIVE: The aim of this study was to investigate the effects of genistein on cytochrome P450 (CYP) gene expression levels in human hepatocellular carcinoma (HepG2/C3A) and colon adenocarcinoma (HT29) cells. METHODS: Real-time RT-PCR was used to examine the expression of genes families involved in xenobiotic metabolism, such as CYP1 (CYP1A1, CYP1B1), CYP2 (CYP2E1, CYP2D6), CYP3 (CYP3A4); and of a family involved in the catabolism of the all-trans-retinoic acid (ATRA), CYP26 (CYP26A1, CYP26B1). RESULTS: RT-qPCR data analysis showed that after 12 h of exposure of HepG2/C3A cells to genistein (5 and 50 µM) there was an upregulation of CYP1A1 and CYP1B1 and downregulation of CYP2D6, CYP26A1 and CYP26B1 mRNA levels. There was no change in the mRNA levels of CYP P450 genes in HT29 cells. CONCLUSION: Our results suggest that treatment with genistein in non-toxic concentrations may impact the expression level of CYPs involved in the biotransformation of xenobiotics and drug metabolizing enzymes. Moreover, the downregulation of ATRA metabolism-related genes opens a new research path for the study of genistein as retinoic acid metabolism blocking agent for treating cancer and other pathologies.

LNO3 AND L3 Are Associated With Antiproliferative And Pro-Apoptotic Action In Hepatoma Cells.

The identification of antitumoral substances is the focus of intense biomedical research. Two structural analogues of thalidomide, LNO3 and L3, are two synthetic compounds that might possess such antitumor properties. We evaluated the toxicological effects of these substances, including cytotoxicity, genotoxicity and induction of apoptosis in HTC cells. Additionally, the production of free radicals (nitric oxide and superoxide) was investigated, and the expression of caspases genes 3, 8, and 9 were determined by RT-qPCR. The compounds exhibited cytotoxic effects that resulted in inhibited cell proliferation. LNO3 showed to be more effective and toxic than L3 in all assays. LNO3 stimulated the release of NO and superoxide, which was accompanied by the formation of peroxynitrite. Apoptosis was induced in a dose-dependent manner by both compounds; however, the expression of caspases 3, 8 and 9 was unchanged. These results suggested that L3 and LNO3 possess antiproliferative and pro-apoptotic effects in HTC cells. Additionally, although they exhibited cytotoxicity, L3 and LNO3 might be useful coadjuvants in tumor treatment studies.