Growth inhibition of human thyroid carcinoma and goiter cells in vitro by the isoflavone derivative 7-(O)-carboxymethyl daidzein conjugated to N-t-boc-hexylenediamine

Promising Approaches in Plant-Based Therapies for Thyroid Cancer: An Overview of In Vitro, In Vivo, and Clinical Trial Studies

Thyroid cancer, particularly undifferentiated tumors, poses a significant challenge due to its limited response to standard therapies. The incidence of thyroid cancer, predominantly differentiated carcinomas, is on the rise globally. Anaplastic thyroid carcinoma (ATC), though rare, is highly aggressive and challenging to treat. Therefore, this study aimed to collect data and explore alternative treatments, focusing on the efficacy of photodynamic therapy (PDT) combined with natural compounds as well as the potential role of phytochemicals, including quercetin, kaempferol, apigenin, genistein, daidzein, naringenin, hesperitin, anthocyanidins, epigallocatechin gallate (EGCG), resveratrol, ellagic acid, ferulic acid, caffeic acid, curcumin, saponins, ursolic acid, indole-3-carbinol (I3C), capsaicin, and piperine in thyroid cancer treatment. PDT, utilizing sensitizers activated by tumor-directed light, demonstrates promising specificity compared to traditional treatments. Combining PDT with natural photosensitizers, such as hypericin and genistein, enhances cytotoxicity against thyroid carcinoma cells. This literature review summarizes the current knowledge on phytochemicals and their anti-proliferative effects in in vitro and in vivo studies, emphasizing their effectiveness and mechanism of action as a novel therapeutic approach for thyroid cancers, especially those refractory to standard treatments.

Natural compounds targeting nuclear receptors for effective cancer therapy

Human nuclear receptors (NRs) are a family of forty-eight transcription factors that modulate gene expression both spatially and temporally. Numerous biochemical, physiological, and pathological processes including cell survival, proliferation, differentiation, metabolism, immune modulation, development, reproduction, and aging are extensively orchestrated by different NRs. The involvement of dysregulated NRs and NR-mediated signaling pathways in driving cancer cell hallmarks has been thoroughly investigated. Targeting NRs has been one of the major focuses of drug development strategies for cancer interventions. Interestingly, rapid progress in molecular biology and drug screening reveals that the naturally occurring compounds are promising modern oncology drugs which are free of potentially inevitable repercussions that are associated with synthetic compounds. Therefore, the purpose of this review is to draw our attention to the potential therapeutic effects of various classes of natural compounds that target NRs such as phytochemicals, dietary components, venom constituents, royal jelly-derived compounds, and microbial derivatives in the establishment of novel and safe medications for cancer treatment. This review also emphasizes molecular mechanisms and signaling pathways that are leveraged to promote the anti-cancer effects of these natural compounds. We have also critically reviewed and assessed the advantages and limitations of current preclinical and clinical studies on this subject for cancer prophylaxis. This might subsequently pave the way for new paradigms in the discovery of drugs that target specific cancer types.

Signal Pathway of Estrogen and Estrogen Receptor in the Development of Thyroid Cancer

The molecular mechanisms underlying the development of thyroid cancer (TC) have been examined through extensive experiments. A large number of studies have shown that the incidences of thyroid cancer in women is much higher than that in men, so estrogen plays a key role in the development of thyroid cancer. Estrogen plays its growth-promoting role through classical genomic and non-genomic pathways mediated by membrane-bound estrogen receptors. It also can affect tumor progression by regulating the tumor microenvironment. We summarize the understanding of molecular mechanisms of estrogen signaling pathways in thyroid cancer. Furthermore, it will provide a new target for the treatment of thyroid carcinoma by blocking estrogen and its related action pathway.

Plant natural products with anti-thyroid cancer activity

Thyroid cancer is the most frequent endocrine malignancy, with more than 500,000 cases per year worldwide. Differentiated thyroid cancers are the most common forms with best prognosis, while poorly/undifferentiated ones are rare (2% of all thyroid cancer), aggressive, frequently metastasize and have a worse prognosis. For aggressive, metastatic and advanced thyroid cancer novel antitumor molecules are urgently needed and phytochemical products can be a rational and extensive source, since secondary plant metabolites can guarantee the necessary biochemical variability for therapeutic purpose. Among bioactive molecules that present biological activity on thyroid cancer, resveratrol, curcumin, isoflavones, glucosinolates are the most common and used in experimental model. Most of them have been studied both in vitro and in vivo on this cancer, but rarely in clinical trial. This review summarizes phytochemicals, phytotherapeutics and plant derived compounds used in thyroid cancer.

Antitumor Effect of Various Phytochemicals on Diverse Types of Thyroid Cancers

Thyroid cancers developed from the tissues of the thyroid gland are classified into papillary (PTC), follicular (FTC), medullary (MTC), and anaplastic thyroid cancer (ATC). Although thyroid cancers have been generally known as mild forms of cancer, undifferentiated MTC and ATC have a more unfavorable prognosis than differentiated PTC and FTC because they are more aggressive and early metastatic. A variety of therapies such as surgery, radiotherapy, and chemotherapy have been currently used to treat thyroid cancer, but they still have limitations including drug resistance or unfavorable side effects. Phytochemicals are plant-derived chemicals having various physiological activities that are expected to be effective in cancer treatment. In this review, anticancer efficacy of phytochemicals, such as resveratrol, genistein, curcumin, and other substances in each type of thyroid cancer was introduced with their chemopreventive mechanisms. English articles related with thyroid cancer and anti-thyroid cancer of phytochemicals were searched from PubMed and Google Scholar. This article mainly focused on in vitro or animal studies on phytochemicals with anti-thyroid cancer activity. These various phytochemicals have been shown to induce apoptosis in all types of thyroid cancer cells, inhibit cell proliferation and invasion, and to be helpful in enhancing the effect of radioiodine therapy that is a typical therapy to thyroid cancer. These results suggest that thyroid cancer can be more effectively treated by the combinations of phytochemicals and the existing therapies or substances.

A sorafenib-sparing effect in the treatment of thyroid carcinoma cells attained by co-treatment with a novel isoflavone derivative and 1,25 dihydroxyvitamin D3

BACKGROUND

Sorafenib improves progression-free survival in patients with progressive radioactive iodine-refractory differentiated thyroid carcinoma, but causes severe side effects. Estrogens may accelerate thyroid carcinoma cell growth. Our group recently reported that isoflavone derivative 7-(O)-carboxymethyl daidzein conjugated to N-t-boc-hexylenediamine (cD-tboc), a novel anti-estrogenic compound, retards the growth of both thyroid carcinoma cell lines and cultured human carcinoma cells. Vitamin D receptor (VDR) is expressed in malignant cells and responds to 1,25 dihydroxyvitamin D3 (1.25D) by decreased proliferative activity in vitro. The purpose of this study was to examine the effects of vitamin D metabolites (VDM) on the expression of estrogen receptors (ERs), VDR, and 1OHase mRNA, and to evaluate the inhibitory effect of low doses of sorafenib in combination with cDtboc and VDM on cell proliferation in cultured human papillary thyroid carcinoma (PTC).

METHODS

In 19 cultured PTC specimens and 19 normal thyroid specimens, harvested during thyroidectomies from the same patients, expression levels of ERα, ERβ, VDR, and 1 alpha-hydroxylase (1OHase) mRNA (by quantitative real-time PCR) were determined at baseline and after treatment with VMD. Cell proliferation was determined by measurement of ³[H] thymidine incorporation after treatment with sorafenib alone, sorafenib with added 1.25D or cD-tboc, and sorafenib with both 1.25D and cD-tboc added.

RESULTS

1,25D increased mRNA expression of all tested genes in the malignant and normal thyroid cells, while the ERα mRNA of the normal cells was unaffected. 1.25D dose-dependently inhibited cell proliferation in the malignant cells. The inhibitory effect of sorafenib on cell proliferation in the malignant cells was amplified after the addition of cDtboc and 1.25D, such that the maximal inhibition was not only greater, but also had been attained at a 10-fold lower concentration of sorafenib (20 μg/ml). This inhibition was similar to that of the generally used concentration of sorafenib (200 μg/ml) alone.

CONCLUSIONS

The demonstration that low concentrations of cDtboc and 1.25D markedly amplify the inhibitory effect of sorafenib on the growth of human PTC supports the use of a 10-fold lower concentration of sorafenib. The findings may promote a new combination treatment for progressive radioactive iodine-refractory PTC.

Soy isoflavones have antimutagenic activity on DNA damage induced by the antileishmanial Glucantime (meglumine antimoniate)

Isoflavones are phytoestrogens reported to be potent antioxidant agents. In contrast, the antileishmanial meglumine antimoniate has mutagenic activities. This study evaluated the ability of soy isoflavones to reduce DNA damage induced by meglumine antimoniate. Antimutagenic effects (by micronucleus test) were tested using Swiss mice divided into seven groups treated with meglumine antimoniate (425 mg/kg bw pentavalent antimony); cyclophosphamide (50 mg/kg bw); water (negative control); single isoflavones dose (1.6 mg/kg bw), and three groups received one dose of isoflavones via gavage (0.4 mg/kg bw, 0.8 mg/kg bw or 1.6 mg/kg bw) plus meglumine antimoniate via intraperitoneal, simultaneously. To evaluate antigenotoxicity (by Comet assay), each group with 10 animals received the above-mentioned control doses; single dose of isoflavones 0.8 mg/kg bw, and three groups received isoflavones (0.8 mg/kg bw) by gavage along with intraperitoneal meglumine antimoniate, which were treated with isoflavones 24 h before or after receiving meglumine antimoniate (pre-treatment and post-treatment, respectively) or simultaneously. Cells were harvested 24 h after the treatment, and the data were evaluated by ANOVA followed by Tukey's test (p < 0.05). The data from the simultaneous treatment by micronucleus test revealed that isoflavones (0.4 and 0.8 mg/kg) were able to reverse the mutagenic effect of Glucantime. Moreover, all regimes of the treatment with 0.8 mg/kg bw dose were able to reduce the genotoxicity caused by meglumine antimoniate. It is suggested that the protective effect of isoflavones against DNA damage is related to their ability to reduce oxidative stress caused by the trivalent Sb(III) metabolite of meglumine antimoniate.

Vitamin D less-calcemic analog modulates the expression of estrogen receptors, vitamin D receptor and 1α-hydroxylase 25-hydroxy vitamin D in human thyroid cancer cell lines

Estrogen receptors (ERs) are expressed in various "non-reproductive" cancer cell types. Some cancer types express 1α-hydroxylase 25-hydroxy vitamin D (1OHase) whose product, 1,25(OH)2D3 can retard cancer cell proliferation. Thyroid carcinoma cell growth is apparently promoted by estrogens, but whether or not this interaction is modified by vitamin D metabolites/analogs is presently unknown. Here we assessed the effect of a less calcemic vitamin D analog [JK 1624 F2-2 (JKF)] in three human thyroid cancer cell lines: ARO (anaplastic carcinoma), NPA (papillary carcinoma) and MRO (follicular carcinoma). (1) All cell lines expressed both ERα and ERβ, vitamin D receptor (VDR) and 1OHase mRNA quantified by Real Time PCR. There was a general abundance of ERβ over ERα expression, such that the ratio of ERβ to ERα mRNA was >1000:1, 228:1 and 7.7:1 in ARO, MRO and NPA cells, respectively. (2) JKF up regulated ERβ expression in ARO (by 110±15%) and MRO (by 280±10%) but down regulated ERβ in NPA cells (by 40±15%). The expression of VDR was up regulated by JKF in NPA (21±6%), down regulated in ARO (-24±7%) and not affected in MRO. (3) All three human thyroid cancer cell lines were found to express 1OHase, which was up regulated by JKF in MRO (350±25%) and NPA (35±8%) but down regulated in ARO (-20±5%). This is the first report to describe direct regulation of VDR and 1OHase expression by a vitamin D analog in human thyroid cancer cells. A functional role for the vitamin D system in human thyroid cancer is suggested by the finding that the vitamin D analog can affect ERs expression which is in turn involved in estrogen-induced cell growth in an ER-type specific manner in these cells.

The key involvement of estrogen receptor β and G-protein-coupled receptor 30 in the neuroprotective action of daidzein

Phytoestrogens have received considerable attention because they provide an array of beneficial effects, such as neuroprotection. To better understand the molecular and functional link between phytoestrogens and classical as well as membrane estrogen receptors (ERs), we investigated the effect of daidzein on the glutamate-mediated apoptotic pathway. Our study demonstrated that daidzein (0.1-10μM) inhibited the pro-apoptotic and neurotoxic effects caused by glutamate treatment. Hippocampal, neocortical and cerebellar tissues responded to the inhibitory action of daidzein on glutamate-activated caspase-3 and lactate dehydrogenase (LDH) release in a similar manner. Biochemical data were supported at the cellular level by Hoechst 33342 and calcein AM staining. The sensitivity of neuronal cells to daidzein-mediated protection was most prominent in hippocampal cultures at an early stage of development 7th day in vitro. A selective estrogen receptor β (ERβ) antagonist, 4-[2-phenyl-5,7-bis(trifluoromethyl)pyrazolo[1,5,-a]pyrimidin-3-yl]phenol (PHTPP), and a selective G-protein-coupled receptor 30 (GPR30) antagonist, 3aS(∗),4R(∗),9bR(∗))-4-(6-Bromo-1,3-benzodioxol-5-yl)-3a,4,5,9b-3H-cyclopenta[c]quinoline (G15), reversed the daidzein-mediated inhibition of glutamate-induced loss of membrane mitochondrial potential, caspase-3 activity, and LDH release. A selective ERα antagonist, methyl-piperidino-pyrazole (MPP), did not influence any anti-apoptotic effect of daidzein. However, a high-affinity estrogen receptor antagonist, 7α,17β-[9-[(4,4,5,5,5-pentafluoropentyl)sulfinyl]nonyl]estra-1,3,5(10)-triene-3,17-diol (ICI) 182,780, and a selective GPR30 agonist, (±)-1-[(3aR(∗),4S(∗),9bS(∗))-4-(6-bromo-1,3-benzodioxol-5-yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinolin-8-yl]-ethanone (G1), intensified the protective action of daidzein against glutamate-induced loss of membrane mitochondrial potential and LDH release. In siRNA ERβ- and siRNA GPR30-transfected cells, daidzein did not inhibit the glutamate-induced effects. Twenty-four hour exposure to glutamate did not affect the cellular distribution of ERβ and GPR30, but caused greater than 100% increase in the levels of the receptors. Co-treatment with daidzein decreased the level of ERβ without significant changing of the GPR30 protein level. Here, we elucidated neuroprotective effects of daidzein at low micromolar concentrations and demonstrated that the phytoestrogens may exert their effects through novel extranuclear GPR30 and the classical transcriptionally acting ERβ. These studies uncover key roles of the ERβ and GPR30 intracellular signaling pathways in mediating the anti-apoptotic action of daidzein and may provide insight into new strategies to treat or prevent neural degeneration.