The quinone-based derivative, HMNQ induces apoptotic and autophagic cell death by modulating reactive oxygen species in cancer cells

Ruthana date extract inhibited proliferation of human hepatocellular carcinoma (HepG2) cells by modulation of BAX gene

Cancer response to chemotherapeutic agents and its side effects remain a challenge for the development of new anticancer compounds. Dates are consumed worldwide due to their high nutritional value. We investigated the cytotoxicity and expression of the proapoptotic BAX gene in human hepatocellular carcinoma (HepG2) cells treated with Ruthana date ethanolic extract (RDE). The RDE ingredients analyzed by GC/MS and HepG2 cells were treated with different concentrations of RDE for 24, 48, and 72 h. Cytotoxicity, cell viability, DNA fragmentation, and BAX expression were determined. The GC/MS analysis of RDE showed its high content of quercetin, myricetin kaempferol, thymine, and catechol as the most active ingredients. HepG2 treated with RDE showed a significant change in morphological characteristics related to cell death. The antiproliferative activity determined by WST-1 demonstrated that RDE significantly reduced cell viability. Cells treated with RDE (10-60 mg) showed gradual DNA fragmentation in a dose-dependent manner. Gene expression analysis showed upregulation of BAX at 30 mg/ml of RDE (p < 0.001). However, it showed downregulation at (40-60 mg/ml) as compared to control. Our findings indicated that RDE exert cytotoxicity against HepG2 cells due to its high content of flavonoids. This effect through DNA fragmentation and activation of the proapoptotic BAX gene.

Anticancer agents based on Plastoquinone analogs with N-phenylpiperazine: Structure-activity relationship and mechanism of action in breast cancer cells

2,3-Dimethyl-1,4-benzoquinones named as Plastoquinone (PQ) analogs have antiproliferative activity and are promising new members of molecules that can be used to cope with cancer. In an attempt to develop effective and potentially safe antiproliferative agents, previously reported twelve Plastoquinone analogs (PQ1-12) have been obtained to understand their antiproliferative profile. All PQ analogs have been selected by the National Cancer Institute (NCI) of Bethesda based on the NCI Developmental Therapeutics Program and tested against the panel of 60 cancer cell lines. Based on those studies, the cytotoxicity of the selected PQ analogs (PQ8, PQ9, PQ11, and PQ12) was determined using four breast cancer cell lines (MCF7, UACC-2087, MDA-MB-231, and MDA-MB-435) and a normal cell line (HaCaT). For better understanding, apoptosis induction, changes in cell proliferation, cell migration, and reactive oxygen species (ROS) generation were investigated for the selected PQ analog (PQ11) on MCF7 and UACC-2087 cell lines. According to the study results, PQ11 showed the most promising anticancer activity against MCF7 cell line through increased oxidative stress and apoptosis and suppression of cell proliferation. Based on the biological activity profile, we hypothesize that PQ11 could be a modulator of the cannabinoid 2 (CB2) receptor. Accordingly, we analyzed molecular level interaction of PQ11 with CB2 receptor through molecular docking simulation and it was also predicted to have a favorable ADMET profile. Overall, our findings suggest that integration of the N-phenylpiperazine moiety can be a good strategy for the structural optimization of PQ analogs as anticancer agents, especially in breast cancer.

Synthesis of Murrayaquinone-A Derivatives and Investigation of Potential Anticancer Properties

A series of novel murrayaquinone a derivatives were synthesized and their anti-cancer activity were evaluated on healthy colon cell lines (CCD-18Co), primary (Caco-2) and metastatic (DLD-1) colon cancer cell lines. The results showed that the cytotoxicity of murrayaquinone molecules is significantly high even in micromolar levels. The DNA binding, cell cycle arrest and metabolic activity studies of these molecules were also carried out and the results showed that these molecules induce apoptosis. In conclusion, the data support further studies on murrayaquinone derivatives toward selection of a candidate for cancer treatment.

Zinc Oxide Nanoparticle Induces Apoptosis in Human Epidermoid Carcinoma Cells Through Reactive Oxygen Species and DNA Degradation

Zinc oxide nanoparticles (ZnO-NPs) are used immensely in technology and medicine, but very less is known about toxicity mechanism to human epidermal cells. The objective of this study was to evaluate possible anticancer properties of ZnO-NPs on human epidermoid carcinoma cells using MTT assay, measurement of reactive oxygen species, DNA fragmentation, and nuclear condensation. ZnO-NPs were synthesized by sol-gel method using zinc acetate dihydrate, ethylene glycol, and 2-propyl alcohol. Numerous characterization techniques such as UV-visible spectroscopy, X-ray powder diffraction, transmission electron microscopy, and dynamic light scattering spectroscopy were used to confirm synthesis, purity, optical, and surface characteristics, size, shape, and distribution of ZnO-NPs. Our finding showed that ZnO-NPs considerably decreased cell viability of human epidermoid carcinoma A431 cells with a parallel increase in nuclear condensation and DNA fragmentation in a dose dependent manner. Moreover, real time PCR expression study showed that treatment of human epidermoid carcinoma cells with ZnO-NPs trigger increased expression of tumor suppressor gene p53, bax, and caspase-3 while downregulate antiapoptotic gene bcl-2. Thus ZnO-NPs induce apoptosis in A431 cells through DNA degradation and generation of reactive oxygen species via p53, bax/bcl-2, and caspase pathways.

Phytochemicals as a Complement to Cancer Chemotherapy: Pharmacological Modulation of the Autophagy-Apoptosis Pathway

Bioactive plant derived compounds are important for a wide range of therapeutic applications, and some display promising anticancer properties. Further evidence suggests that phytochemicals modulate autophagy and apoptosis, the two crucial cellular pathways involved in the underlying pathobiology of cancer development and regulation. Pharmacological targeting of autophagy and apoptosis signaling using phytochemicals therefore offers a promising strategy that is complementary to conventional cancer chemotherapy. In this review, we sought to highlight the molecular basis of the autophagic-apoptotic pathway to understand its implication in the pathobiology of cancer, and explore this fundamental cellular process as a druggable anticancer target. We also aimed to present recent advances and address the limitations faced in the therapeutic development of phytochemical-based anticancer drugs.

Myricetin induces apoptosis and autophagy by inhibiting PI3K/Akt/mTOR signalling in human colon cancer cells

BACKGROUND

The compound 3,3',4',5,5',7-hexahydroxyflavone (myricetin) is a natural flavonoid with antitumour activity. Most of the studies on myricetin have focused on the induction of tumour cell apoptosis, and little is known about the regulatory effects of myricetin on autophagy in colorectal cancer.

METHODS

Here, we studied the effects of myricetin on colon cancer cell proliferation, apoptosis and autophagy. We detected colon cancer cell apoptosis induced by myricetin via flow cytometry and Hoechst 33258 staining. Transmission electron microscopy was performed to observe the morphological changes associated with autophagy. The expression levels of apoptosis-, autophagy- and PI3K/Akt/mTOR signalling-related proteins were measured by Western blot analysis.

RESULTS

This study confirmed that myricetin inhibits the proliferation of 4 kinds of colon cancer cell lines. Myricetin induced cell apoptosis and autophagy by inhibiting PI3K/Akt/mTOR signalling pathway. In addition, the inhibition of autophagy with 3-methyladenine (3-MA) promoted the apoptosis of myricetin-treated colon cancer cells.

CONCLUSIONS

Considering that myricetin induces apoptosis and autophagy in colon cancer cells, myricetin may become a viable candidate for chemotherapy; it could be used to exert tumour inhibitory effects alone or as adjuvant chemotherapy to inhibit autophagy. These studies may provide further evidence for the potential use of myricetin in the treatment of colon cancer.

Apoptotic events induced by a natural plastoquinone from the marine alga Desmarestia menziesii in lymphoid neoplasms

There exists an urgent need for the development of new drugs for the treatment of lymphoid neoplasms. The aim of this study was to evaluate the cytotoxic effect of the marine plastoquinone 9'-hydroxysargaquinone (9'-HSQ), focusing on investigation of the mechanism by which it causes death in lymphoid neoplastic cells. This particular plastoquinone reduced the cell viability of different hematological tumor cell lines in a time-dependent and concentration-dependent manner. Intrinsic apoptosis occurred with time-dependent reduction of mitochondrial membrane potential (42.3 ± 1.1% of Daudi cells and 18.6 ± 5.6% of Jurkat cells maintained mitochondrial membrane integrity) and apoptosis-inducing factor release (Daudi: 133.3 ± 8.1%, Jurkat: 125.7 ± 6.9%). Extrinsic apoptosis also occurred, as reflected by increased FasR expression (Daudi: 139.5 ± 7.1%, Jurkat: 126.0 ± 1.0%). Decreases were observed in the expression of Ki-67 proliferation marker (Daudi: 67.5 ± 2.5%, Jurkat: 84.3 ± 3.8%), survivin (Daudi: 66.0 ± 9.9%, Jurkat: 63.1 ± 6.0%), and NF-κB (0.7 ± 0.04% in Jurkat cells). Finally, 9'-HSQ was cytotoxic to neoplastic cells from patients with different lymphoid neoplasms (IC50: 4.9 ± 0.6 to 34.2 ± 0.4 µmol/L). These results provide new information on the apoptotic mechanisms of 9'-HSQ and suggest that it might be a promising alternative for the treatment of lymphoid neoplasms.

Cisplatin and farnesol co-encapsulated PLGA nano-particles demonstrate enhanced anti-cancer potential against hepatocellular carcinoma cells in vitro

Cisplatin (CDDP) is a potent chemotherapeutic drug, but its severe side-effects often prohibit its use. Combined treatment with CDDP plus Farnesol (FAR) and their co-encapsulated nano form were investigated in in vitro to examine if synergistic cytotoxicity of this combination could reduce unwanted side-effects of CDDP chemotherapy and potentiate CDDP anticancer activity against hepatocellular carcinoma (HCC) cells. After finding combination therapy of CDDP and FAR successfully combat HCC we formulated co-encapsulation of CDDP and FAR within poly(lactic-co-glycolic acid) copolymer (NCDDPFAR) by following the standardized solvent displacement method. NCDDPFAR treatment caused faster drug mobility, sustained particle release, site-specific action and higher percentage of apoptotic death compared with single drug treatment even at relatively low concentrations. Co-encapsulation of two drugs exhibited additive effects against HCC; FAR reduced CDDP-induced glutathione level by increasing expression of CYP2E1 while CDDP directly interacted with DNA; FAR up-regulated the expression of TopII, thereby promoting DNA breaks and escaping DNA repair machinery. Expression pattern of apoptotic genes like p53, Bax, cytochrome c and caspase-3 suggested that NCDDPFAR induced HCC cell death through mitochondrial intrinsic pathway. Administration of NCDDPFAR had better ability of drug carriage and enhanced anticancer potentials against HCC cells.

Vernolactone Promotes Apoptosis and Autophagy in Human Teratocarcinomal (NTERA-2) Cancer Stem-Like Cells

Vernonia zeylanica, is a shrub endemic to Sri Lanka. V. zeylanica has been used in Sri Lankan traditional medicine for the treatment of various diseases and conditions. The present study was designed to determine antiproliferative, apoptotic, autophagic, and antioxidant effects of vernolactone, isolated from V. zeylanica, in human embryonal carcinoma cells (NTERA-2, a cancer stem cell model). Antiproliferative effects of vernolactone in NTERA-2 cells and human peripheral blood mononuclear cells (control cells) were evaluated using the Sulforhodamine B (SRB) assay and WST-1 antiproliferative assays, respectively. The antiproliferative effect of vernolactone was further investigated using the colony formation assay. Effects of vernolactone on apoptosis were investigated by phase contrast light microscopic and fluorescence microscopic analysis, caspase 3/7 expression, and real-time PCR of apoptosis-associated genes p53 and Survivin. The effect of vernolactone on NTERA-2 cell migration was monitored using the wound healing assay. Effects of vernolactone on the expression of autophagy-related genes (LC3, Beclin 1, PI3K, Akt, and mTOR) were evaluated using real-time PCR. 2,2-Diphenyl-1-2,2-diphenyl-picrylhydrazyl (DPPH) radical scavenging assay, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, and ferric reducing antioxidant power (FRAP) assays were also carried out to evaluate the antioxidant activity of vernolactone. Overall results confirm that vernolactone can exert antiproliferative effects, induce apoptosis and autophagy, and decrease NTERA-2 cell migration in a dose- and time-dependent manner with a very small antioxidant property.

ROS-Mediated Cancer Cell Killing through Dietary Phytochemicals

Reactive oxygen species (ROS) promote carcinogenesis by inducing genetic mutations, activating oncogenes, and raising oxidative stress, which all influence cell proliferation, survival, and apoptosis. Cancer cells display redox imbalance due to increased ROS level compared to normal cells. This unique feature in cancer cells may, therefore, be exploited for targeted therapy. Over the past few decades, natural compounds have attracted attention as potential cancer therapies because of their ability to maintain cellular redox homeostasis with minimal toxicity. Preclinical studies show that bioactive dietary polyphenols exert antitumor effects by inducing ROS-mediated cytotoxicity in cancer cells. These bioactive compounds also regulate cell proliferation, survival, and apoptotic and antiapoptotic signalling pathways. In this review, we discuss (i) how ROS is generated and (ii) regulated and (iii) the cell signalling pathways affected by ROS. We also discuss (iv) the various dietary phytochemicals that have been implicated to have cancer therapeutic effects through their ROS-related functions.

The design of 1,4-naphthoquinone derivatives and mechanisms underlying apoptosis induction through ROS-dependent MAPK/Akt/STAT3 pathways in human lung cancer cells

The natural compound 1,4-naphthoquinone has potent anti-tumor activity. However, the clinical application of 1,4-naphthoquinone and its derivatives has been limited by their side effects. In this study, we attempted to reduce the toxicity of 1,4-naphthoquinone by synthesizing two derivatives: 2,3-dihydro-2,3-epoxy-2-propylsulfonyl-5,8-dimethoxy-1,4-naphthoquinone (EPDMNQ) and 2,3-dihydro-2,3-epoxy-2-nonylsulfonyl-5,8-dimethoxy-1,4-naphthoquinone (ENDMNQ). Then we evaluated the cytotoxicity and molecular mechanisms of these compounds in lung cancer cells. EPDMNQ and ENDMNQ significantly inhibited the viabilities of three lung cancer cell lines and induced A549 cell cycle arrest at the G1 phase. In addition, they induced the apoptosis of A549 lung cancer cells by increasing the phosphorylation of p38 and c-Jun N-terminal kinase (p-JNK), and decreasing the phosphorylation of extracellular signal-related kinase (p-ERK), protein kinase B (Akt), and signal transducer and activator of transcription 3 (STAT3). Furthermore, they increased reactive oxygen species (ROS) levels in A549 cells; however, pretreatment with the ROS inhibitor N-acetyl-l-cysteine significantly inhibited EPDMNQ- and ENDMNQ-mediated apoptosis and reversed apoptotic proteins expression. In conclusion, EPDMNQ and ENDMNQ induced G1 phase cell cycle arrest and apoptosis in A549 cells via the ROS-mediated activation of mitogen activated protein kinase (MAPK), Akt and STAT3 signaling pathways.

Cytostatic and Anti-tumor Potential of Ajwa Date Pulp against Human Hepatocellular Carcinoma HepG2 Cells

Ajwa dates (Phoenix dactylifera L.) are used by traditional therapeutic practitioners for several health benefits but most remain to be scientifically validated. In this study, we evaluated the apoptosis-inducing effect of ethanolic extract of Ajwa date pulp (ADP) on human hepatocellular carcinoma (HCC) HepG2 cells. High performance liquid chromatography analysis revealed the presence of polysaccharide β-D-glucan in ADP extract. Treated HCC cells revealed morphological characteristics of apoptosis under phase contrast microscopy. MTT assay demonstrated significant (p < 0.05) dose- and time-dependent inhibition of HCC cell growth. HCC cells were found to be in late apoptotic stage on treatment with higher doses of ADP extract as depicted by acridine orange/ethidium bromide and Annexin V-FITC/PI double stain. Importantly, ADP extract increased the reactive oxygen species level and decreased the mitochondrial membrane potential in treated HCC cells. Flow cytometry analysis demonstrated that ADP extract induced elevation of S and G2/M phases of cell cycle. Moreover, ADP extract induced apoptosis in HCC cells independent of tumor suppressor genes viz. CHEK2, ATM and TP53. Interestingly, ADP extract did not display any significant effect on normal cell line Vero. This study provides validation that ADP extract can be considered as a safe and natural potential drug candidate against human liver cancer.