Cancer Letters

Cancer Letters

Volume 245, Issues 1–2, 8 January 2007, Pages 156-162
Cancer Letters

Gallic acid inhibits ribonucleotide reductase and cyclooxygenases in human HL-60 promyelocytic leukemia cells

https://doi.org/10.1016/j.canlet.2006.01.001Get rights and content

Abstract

Gallic acid (GA) is a naturally occurring polyhydroxyphenolic compound and an excellent free radical scavenger. In this study, we examined its cytotoxic and biochemical effects on the human HL-60 promyelocytic leukemia cell line. GA caused a significant imbalance of deoxynucleosidetriphosphate (dNTP) pool sizes, indicating ribonucleotide reductase inhibition. Moreover, GA induced dose-dependent apoptosis in HL-60 cells (80 μM GA led to the induction of apoptosis in 39% of cells) and attenuated progression from G0/G1 to the S phase of the cell cycle (60 μM GA doubled the number of cells in G0/G1 phase from 22 to 44% when compared to untreated controls). We further determined IC50 values of 3.5 and 4.4 nM for the inhibition of cyclooxygenases I and II, respectively. When cells were simultaneously treated with GA and trimidox, another inhibitor of RR, highly synergistic growth inhibitory effects could be observed. Taken together, we identified novel biochemical effects of GA which could be the basis for further preclinical and in vivo studies.

Introduction

Gallic acid (GA, 3,4,5-trihydroxybenzoic acid, Fig. 1) is a polyhydroxyphenolic compound, which can be found in various natural products, like gallnuts, sumac, tea leaves, oak bark, green tea, apple-peels, grapes, strawberries, pineapples, bananas, lemons, and in red and white wine [1], [2], [3]. GA can be present as free molecule or as part of the tannin molecule.

In particular, red wine has a high content of this phenolic acid and GA might be, together with resveratrol, responsible for the ‘French paradox’. This is the phenomenon of significantly lower (40%) heart infarction incidence in the French population, when compared with other European countries or the USA [4], [5], [6], and likely due to higher red wine consumption in France. It was recently shown that GA antagonizes P-selectin mediated platelet leucocyte interactions [7], which could be jointly responsible for the beneficial effects of red wine and the French paradox.

Other beneficial effects might be the antidiabetic and antiangiogenic effects of GA containing fruit extracts [8], [9]. It was even revealed that GA from rose flowers exhibits antioxidative effects in senescence accelerated mice and can reinstate the activities of catalase and gluthation peroxidase in these animals [10]. GA was described as an excellent free radical scavenger and as an inducer of differentiation and programmed cell death in a number of tumor cell lines [11], [12], [13], [14], [15]. GA may also play an important role in the prevention of malignant transformation and cancer development. It was shown that GA and its derivatives can induce Ca2+ dependent apoptosis in leukemia cells [16], [17]. In addition, it was reported that GA inhibits superoxide dismutase during apoptosis in HL-60 leukemia cells [18]. In this study, we attempted to identify additional biochemical targets of GA in human leukemia cells.

One of these targets is ribonucleotide reductase (RR, EC 1.17.4.1), which is the rate limiting enzyme of de novo DNA synthesis with relatively low activity in resting normal cells and significantly elevated enzyme activity in malignant tumor cells [19], [20]. The enzyme is therefore considered to be an important target for cancer chemotherapy [21]. It was shown earlier that compounds like didox (3,4-dihydroxybenzohydroxamic acid) or trimidox (3,4,5-trihydroxybenzamidoxime, Fig. 1), which have a chemical structure related to GA, and also act as free radical scavengers, are effective inhibitors of this enzyme [22]. RR is blocked by free radical scavengers through inhibition of the non-heme iron subunit of the enzyme, which requires a free tyrosine radical for activity. Both didox and trimidox proved to be effective antitumor and antiviral compounds in vitro and in vivo [23], [24], [25].

Therefore, it was examined whether GA inhibits the activity of RR and whether incubation of human HL-60 promyelocytic leukemia cells with GA affects steady state deoxynucleosidetriphosphate pools (dNTPs), which are the products of RR metabolism. In addition, we determined the effects of GA on apoptosis, necrosis, on cell cycle phase specific alterations, and on cyclooxygenases I and II. Based on these results, we also tested the combination effects of GA together with trimidox on the growth of HL-60 cells. Our results should help to further investigate a natural compound, which might be used in the prevention and treatment of hematological malignancies.

Section snippets

Chemicals

Gallic acid (GA) and Ara-C were purchased from SIGMA, Vienna, Austria. Trimidox was synthesized and provided by Dr Bart van't Riet of Molecules for Health in Richmond, Virginia. All other reagents used were of highest purity available. Structural formulas are depicted in Fig. 1.

Cell culture

HL-60 human promyelocytic cells were purchased by ATCC (American Type Culture Collection, Manassas, VA, USA). Cells were grown in logarithmical growth phase in RPMI 1640 medium supplemented with 10% heat inactivated

Growth inhibition of HL-60 cells by gallic acid and trimidox

Logarithmically growing cells were incubated with various concentrations of GA or trimidox for 72 h. Then cell counts were determined as described in Section 2. GA and trimidox showed 50% growth-inhibitory effects (IC50 values) at concentrations of 24 and 19 μM, respectively. These are concentrations which can be achieved under therapeutic conditions in humans. Results are shown in Table 1.

Combination effects of gallic acid and trimidox on the growth of HL-60 cells

When HL-60 cells were simultaneously incubated with GA and trimidox for 72 h, additive or synergistic growth

Discussion

Like other polyhydroxyphenols, gallic acid also demonstrated significant growth inhibitory and antitumor effects in various leukemia and solid tumor models in vitro and in vivo [29]. Polyhydroxy-substituted compounds like resveratrol, didox or trimidox proved to be not only free radical scavengers, but also effective inhibitors of the enzyme ribonucleotide reductase (RR), which is rate limiting for de novo DNA synthesis in tumor cells. Therefore, the enzyme was considered to be an excellent

References (32)

  • Z. Horvath et al.

    Synergistic action of resveratrol, an ingredient of wine, with Ara-C and tiazofurin in HL-60 human promyelocytic leukemia cells

    Exp. Hematol.

    (2005)
  • T. Szekeres et al.

    Synergistic growth inhibitory and differentiating effects of trimidox and tiazofurin in human promyelocytic leukemia HL-60 cells

    Blood

    (1994)
  • D. De Beer et al.

    Antioxidant activity of South African red and white cultivar wines: free radical scavenging

    J. Agric. Food Chem.

    (2003)
  • J. Sun et al.

    Antioxidant and antiproliferative activities of common fruits

    J. Agric. Food Chem.

    (2002)
  • K. Wolfe et al.

    Antioxidant activity of apple peels

    J. Agric. Food Chem.

    (2003)
  • J.L. Richard

    Coronary risk factors. The French paradox

    Arch. Mal. Coeur Vaiss.

    (1987)
  • Cited by (134)

    • Antioxidant and anticancer activities of gallic acid loaded sodium alginate microspheres on colon cancer

      2022, Current Applied Physics
      Citation Excerpt :

      Therefore, it has become a focal point in cancer treatments. GA has a very good radical scavenger, inhibiting cancer development and preventing conversion to malignant cancer cells [23,28,33]. Besides its antioxidant activities [21,22,26,32,34], GA also has anti-inflammatory and antidiabetic [32], antiangiogenic and antimelanogenic [25], antibacterial [35], antiviral [21,35], antifungal [21], hypoallergenic, antiulcer [21,32], antimutagenic effects [23] and wound healing activities [36].

    • Phytochemical rich extract from the spent material generated from Industrial Dashamoola preparation (a medicinal Ayurvedic decoction) with antioxidant, antidiabetic and anti-inflammatory potential

      2020, Industrial Crops and Products
      Citation Excerpt :

      Gallic acid ((3,4,5-trihydroxybenzoic acid) and chlorogenic acid (5.158 mg/g) have the ability to fight viral and microbial infections (Sorrentino et al., 2018) alongside stabilizing obesity and hypertension by affecting lipid metabolism (Naveed et al., 2018). Gallic acid is a potent bile stimulator with profound antioxidant efficacy (Anand et al., 1997), anticancerous (Asci et al., 2017; Ho et al., 2010; Yoshioka et al., 2000, Nam et al., 2016; Madlener et al., 2007), hepatoprotective (Jadon et al. (2007)). Antioxidant properties of gallic acid are leveraged for the natural color enhancement of fruit-based beverages (Navruz et al., 2016; Roidoung et al., 2016) and as an oxidation barrier in double emulsions (Silva et al., 2018).

    View all citing articles on Scopus
    View full text