The anticancer effects of daily consumption of polyphenols. These dietary polyphenols include chlorogenic acid, curcumin, epigallocatechin-3-O-gallate, genistein, quercetin, and resveratrol. These polyphenols have similar chemical and biological properties in that they can act as antioxidants and exert the anticancer effects via cell signaling pathways involving their reactive oxygen species (ROS)-scavenging activity. These polyphenols may also act as pro-oxidants under certain conditions, especially at high concentrations. Epigenetic modifications, including dysregulation of noncoding RNAs (ncRNAs) such as microRNAs, long noncoding RNAs, and circular RNAs are now known to be involved in the anticancer effects of polyphenols. These polyphenols can modulate the expression/activity of the component molecules in ROS-scavenger-triggered anticancer pathways (RSTAPs) by increasing the expression of tumor-suppressive ncRNAs and decreasing the expression of oncogenic ncRNAs in general. Multiple ncRNAs are similarly modulated by multiple polyphenols. Many of the targets of ncRNAs affected by these polyphenols are components of RSTAPs. Therefore, ncRNA modulation may enhance the anticancer effects of polyphenols via RSTAPs in an additive or synergistic manner, although other mechanisms may be operating as well.

| miRs | miR-16 | miR-22 | miR-34a | miR-141 | miR-145 | miR-146a | miR-200c |
|---|---|---|---|---|---|---|---|
| miR-221 | |||||||
| Polyphenols | |||||||
| [ | 78 | ] |
| CUR | EGCG | GEN | QUE | RES | |
|---|---|---|---|---|---|
| miR-7 SET8↓, Bcl-2↓, p53↑ [80]; Skp2↓, p57↑, p21↑ [81] miR-9 AKT↓, FOXO1↓ [82]; GSK-3β↑, β-catenin↑, Cyclin D1↓ [83] miR-15a Bcl-2↓ [9]; WT1↓ [84] miR-16-1 WT1↓ [84] miR-28-5p BECN1↓ [85] miR-29a DNMT1↓, 3A↓, 3B↓ [86] miR-30c-5p MTA1↓ [87] miR-33b HMGA2↓ [88]; XIAP↓ [89] miR-98 LIN28A↓, MMP2↓, MMP9↓ [90] miR-99a JAK1↓, STAT1↓, STAT3↓ [91] miR-101 EZH2↓, EpCAM↓ [92]; Notch1↓ [93]; EZH2↓ | CUR Yang et al. [9] EGCG Tsang et al.[10] QUE Sonoki et al. [11]; Zhao et al. [12] RES Hagiwara et al. [13]; Azimi et al. [10 | ||||
| Polyphenols | [94] miR-124 Midkine↓ [95]CGA Huang et al. [46]] CUR |
miR-125a ERRα↓ [96] miR-138 Smad4↓, NF-kB↓, Cyclin D3↓ [97] miR-143 NF-kB↓ [98]; PGK1↓ [99]; Autophagy via ATG2B↓ [100] miR-181b CXCL1↓ [101] miR-185 DNMT1↓, 3A↓, 3B↓ [86] miR-192-5p XIAP↓ [102]; PI3K↓, AKT↓ [103]; Wnt/β-catenin↓ [104] miR-196b ** BCR-ABL↓ [55] miR-206 mTOR↓, AKT↓ [105] miR-215 XIAP↓ [102] miR-340 XIAP↓ [106] miR-384 circ-PRKCA↓ [107] | 127 | ] let-7c Numbl/Notch1↑ [128] |
miR-424-3p Galectin-3↓ [129] |
| CGA | CUR | EGCG | GEN | QUE | RES | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| miR-17 p21↑, G0/G1 arrest↑ [46] | [14] QUE Sonoki et al. [11]; Zhao et al. Gandhy et al. [47] EGCG[12] RES Hagiwara et al. [13]; Azimi et al. Mirzaaghaei et al. [48] RES Dhar et al. [49][14] |
; Dhar et al. [50]miR-491 PEG10↓ |
miR-19a,b PTEN↑ [131][108 miR-125a-5p TP53↑ [132]] miR-593 MDR1↓ miR-130a Nkd2↑ [133][ miR-7641 p16↑ [134]CUR Sun et al. [15]; Sreenivasan et al. |
109]CGA Wang et al. [[16]; Sibbesen et al. 51] CUR[17] EGCG Li et al. Mudduluru et al. [52][18; Subramaniam et al. [53]] QUE Zhang et al. [19] |
; Zhang et al. [54]; Taverna et al. |
miR-15b STIM2↓, Orai1↓ [110] miR-29b KDM2A↓ [111] miR-485-5p RXRα↓ [112][55]; Yallapu et al. [56] EGCG Fix et al. [57] **; Siddiqui et al. [58] GEN Zaman et al. [59] RES Tili et al. [60]; Sheth et al. [61]; Liu et al. [62]; Li et al. [63]; Zhou et al. [64] let-7b HMGA2↓ [113]CUR |
miR-98-5p CTR1↑ [135] Guo et al. [20]; Sun et al. [21]; Toden et al. [22]; Sun et al. [15] EGCG Chakrabarti et al. [23]; Li et al. [18]; Chakrabarti et al. [24]; Toden et al. [25]; Mostafa et al. [26] GEN Hsieh et al. [27]; Xia et al. [28]; Chiyomaru et al. [29] RES Hagiwara et al. [ |
CUR13]; Otsuka et al. Sun et al. [15] EGCG Fix et al. [57] **; Gordon et al. [34][30]; Kumazaki et al. [31]; Yao et al. [32] |
; Zan et al. [65] RES Tili et al. miR-574-3p RAC1↓, EGFR↓, EP300↓ [114][ miR-1469 Mcl1↓ [115] let-7d THBS1↓ [116] |
miR-23b-3p PTEN↑ [136]60 miR-151a-5p CASZ1↑, IL1RAPL1↑, SOX17↑, N4BP1↑, ARHGDIA↑ [137] miR-155 PTEN↑ [73] miR-221 miR-222 ARHI↑ [78]] miR-223 Fbw7↑ [138] miR-223 E-cadherin↑ [139] miR-873-5p FOXM1↓ [140] miR-1260b CUR Toden et al. [33] EGCG Gordon et al. |
sFRP1↑, Smad4↑, Dkk2↑ [141][142]CUR[34] GEN Chiyomaru et al. [35] RES Hagiwara et al. [13] |
Toden et al. [22]; Noratto et al. [66] EGCG Fix et al. [57] ** GEN Xia et al. [67]; Xu et al. [68]; Sun et al. miR-1-3p TAGLN2↓ [117] miR-16-5p WEE1↓ [118][ miR-22 Wnt1↓ [19] miR-34a-5p SNHG7↓ [119] miR-142-3p HSP70 ↓ [120]69] miR-197 IGFBP5↓ [121] miR-200b-3p Notch1↓ [122] miR-217 KRAS↓ [123] miR-503-5p Cyclin D1↓ [124] miR-1254 CD36↓ [125] miR-1275 CUR Mirgani et al. [36]; Liu et al. [37] EGCG Toden et al. [25] GEN Wei et al. |
CGA[38] QUE Zhou et al. Huang et al. [46[39] RES Sachdeva et al. ][ EGCG Chakrabarti et al. [23]40] |
; Chakrabarti et al. [24] RES Singh et al. [70]CUR Wu et al. [41] GEN Li et al. [42] QUE Tao et al. [ |
CGA Huang et al. [46]43 EGCG] |
Chakrabarti et al. [23] RES Dhar et al. [50]; Dhar et al. [49]CUR Toden et al. [33]; Soubani et al. [44] EGCG Toden et al. [ |
IGF2BP1↓, IGF2BP3↓ | miR-30d-5p Notch↓ Wnt↓ [143][126] let7-a KRAS↓ [ |
miR-196b ** miR-1290 IGFBP3↑ [CGA25]
* Targets upregulated and downregulated by polyphenols through upregulation of miRs are indicated by ↑ and ↓, respectively. Bcl-2; B-cell lymphoma 2, HOXA10; homeobox A10, SP1; specificity protein 1, ESR1; estrogen receptor alpha 1, Erbb3; Erb-b2 receptor tyrosine kinase 3, NCoA1; nuclear receptor coactivator 1, HDAC6; histone deacetylase 6, MYCBP; Myc binding protein, PTEN; phosphatase and tensin homolog deleted on chromosome 10, Wnt1; wingless and int-1, EMT; epithelial-mesenchymal transition, RTCB; RNA 2′,3′-cyclic phosphate and 5′-OH ligase, ROS; reactive oxygen species, HOTAIR; HOX transcript antisense RNA, Notch-1; Notch homolog protein 1, Sirt1; sirtuin 1, ABCE1; ATP-binding cassette E1, NF-κB; nuclear factor-κB, EGFR; epidermal growth factor receptor, MTA-2; metastasis-associated 2, Bax; Bcl2-associated X protein, MT1-MMP; membrane type 1-matrix metalloproteinase, Bmi-1; B-cell-specific Moloney murine leukemia virus integration site 1, CDK; cyclin-dependent kinase, E2F3; E2F transcription factor 3, HNRNPA1; heterogeneous nuclear ribonucleoprotein A1, Oct4; octamer-binding transcription factor 4, SOX-2; SRY [sex determining region Y]-box 2, ZEB1; zinc finger E-box binding homeobox 1.
Table 2. Modulation of molecular targets of oncogenic miRs downregulated by three to five CGA, CUR, EGCG, QUE, RES and GEN.
* Upregulation (↑) and downregulation (↓) of miR targets by polyphenols are indicated. ** Upregulation by CUR is also reported [55]. PTEN; phosphatase and tensin homolog deleted on chromosome 10, Nkd2; naked cuticle homolog 2, CTR1; copper transporter 1, CASZ1; castor zinc finger 1, IL1RAPL1; interleukin 1 receptor accessory protein like 1, SOX17; SRY-box transcription factor 17, N4BP1; NEDD4-binding protein 1, ARHGDIA; rho-GDP dissociation inhibitor-alpha, ARHI; age-related hearing impairment, Fbw7; F-Box and WD repeat domain-containing 7, FOXM1; forkhead box M1, sFRP1; secreted frizzled-related protein 1, Smad; small mother against decapentaplegic, Dkk2; Dickkopf-related protein 2, Wnt; wingless and int-1, IGFBP; insulin-like growth factor binding protein.
2. Involvements of miRs in Polyphenol-Mediated Anticancer MechanismsmiRs are defined as small single-stranded molecules (approximately 20 to 25 nucleotides) and can regulate gene expression at the transcriptional and post-transcriptional levels, leading to modulation of beneficial health effects exerted by these polyphenols in diseases including cancer [7][8].
Table 1 and Table 2 summarize miRs modulated by at least three of six dietary polyphenols. Four of six dietary polyphenols upregulate miR-16, 34a and 141, and downregulate miR-20a and 221; five of six dietary polyphenols upregulate miR-145 and downregulate miR-21 and 155. Table 1 and Table 2 also list the molecular targets of miRs that are modulated by these polyphenols; targets associated with RSTAPs (Figure 1) are also shown in these tables. Thus, it appears that six dietary polyphenols can exert their anticancer effects not only by directly involving RSTAPs, but also by miR-mediated regulation of the molecular targets associated with RSTAPs.
One or two of the miRs up- and down-regulated by six polyphenols for which studies have been reported are listed in Table 3 and Table 4, respectively, together with determined or proposed targets of these miRs. Many miRs can target components of RSTAPs, but some contribute to other mechanisms that are not depicted in these pathways (Figure 1). Based on previous findings on positive crosstalk between NF-κB and Wnt/β-catenin signaling [144][145], the Wnt/β-catenin signaling is connected in Figure 1. Furthermore, previous findings are incorporated to show that TNF-α activates Wnt/β-catenin pathway, leading to increases in cancer stemness and epithelial-to-mesenchymal transition (EMT) which are involved in cancer cell renewals and tumorigenesis [146][147][148]. |