Alpha-lipoic acid induces sodium iodide symporter expression in TPC-1 thyroid cancer cell line

Selenium bioavailability modulates the sensitivity of thyroid cells to iodide excess

INTRODUCTION

Iodide is an essential micronutrient for the synthesis of thyroid hormones and its imbalance is involved in the origin of different thyroid pathological processes. Selenium (Se) is another essential trace element that contributes to thyroid preservation through the control of the redox homeostasis. Different studies have demonstrated that sodium-iodide-symporter (NIS) is downregulated in the presence of iodide excess and Se supplementation reverses this effect. We also demonstrated that NOX4-derived ROS are involved in NIS repression induced by iodide excess. The aim of this study was to investigate how Se bioavailability is decisive in the sensitivity to iodide excess on a differentiated rat thyroid cell line (FRTL-5).

RESULTS

We demonstrated that siRNA-mediated silencing of Nox4 suppressed AKT phosphorylation induced by iodide excess. Iodide increases TGF-β1 mRNA expression, AKT phosphorylation, ROS levels and decreases GPX1 and TXRND1 mRNAs expression while Se reversed these effects. Furthermore, iodide induced Nrf2 transcriptional activity only in Se-supplemented cultures, suggesting that Se positively influences Nrf2 activation and selenoenzyme response in FRTL-5. Se, also inhibited NF-κB phosphorylation induced by iodide excess. In addition, we found that iodide excess decreased total phosphatase activity and PTP1B and PTEN mRNA expression. Se supply restored only PTEN mRNA expression. Finally, we studied the 2-α-iodohexadecanal (2-IHD) effects since it has been proposed as intermediary of iodide action on thyroid autoregulation. 2-IHD stimulated PI3K/AKT activity and reduced NIS expression by a ROS-independent mechanism. Also, we found that 2-IHD increased TGF-β1 mRNA and TGF-β inhibitor (SB431542) reverses the 2-IHD inhibitory effect on NIS mRNA expression, suggesting that TGF-β1 signaling pathway could be involved. Although Se reduced 2-IHD-induced TGFB1 levels, it could not reverse its inhibitory effect on NIS expression.

CONCLUSION

Our study suggests that Se bioavailability may improve the expression of antioxidant genes through the activation of Nrf2, interfere in PI3K/AKT signaling and NIS expression by redox modulation.

Molecular and Therapeutic Insights of Alpha-Lipoic Acid as a Potential Molecule for Disease Prevention

Alpha-lipoic acid is an organic, sulfate-based compound produced by plants, humans, and animals. As a potent antioxidant and a natural dithiol compound, it performs a crucial role in mitochondrial bioenergetic reactions. A healthy human body, on the other hand, can synthesize enough α-lipoic acid to scavenge reactive oxygen species and increase endogenous antioxidants; however, the amount of α-lipoic acid inside the body decreases significantly with age, resulting in endothelial dysfunction. Molecular orbital energy and spin density analysis indicate that the sulfhydryl (-SH) group of molecules has the greatest electron donating activity, which would be responsible for the antioxidant potential and free radical scavenging activity. α-Lipoic acid acts as a chelating agent for metal ions, a quenching agent for reactive oxygen species, and a reducing agent for the oxidized form of glutathione and vitamins C and E. α-Lipoic acid enantiomers and its reduced form have antioxidant, cognitive, cardiovascular, detoxifying, anti-aging, dietary supplement, anti-cancer, neuroprotective, antimicrobial, and anti-inflammatory properties. α-Lipoic acid has cytotoxic and antiproliferative effects on several cancers, including polycystic ovarian syndrome. It also has usefulness in the context of female and male infertility. Although α-lipoic acid has numerous clinical applications, the majority of them stem from its antioxidant properties; however, its bioavailability in its pure form is low (approximately 30%). However, nanoformulations have shown promise in this regard. The proton affinity and electron donating activity, as a redox-active agent, would be responsible for the antioxidant potential and free radical scavenging activity of the molecule. This review discusses the most recent clinical data on α-lipoic acid in the prevention, management, and treatment of a variety of diseases, including coronavirus disease 2019. Based on current evidence, the preclinical and clinical potential of this molecule is discussed.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s43450-023-00370-1.

Nevirapine Increases Sodium/Iodide Symporter-Mediated Radioiodide Uptake by Activation of TSHR/cAMP/CREB/PAX8 Signaling Pathway in Dedifferentiated Thyroid Cancer

Nevirapine has been proved to be effective in inducing re-differentiation and suppressing tumor growth in several tumor cells. This study aims to investigate the therapeutic potential of nevirapine in dedifferentiated thyroid cancer (DeTC), which refractory to radioiodine treatment and the underlying mechanisms. The results indicated that nevirapine significantly inhibited the proliferation and increased the expressions of thyroid differentiation-related genes, thyroid stimulating hormone receptor (TSHR), sodium/iodide symporter (NIS), thyroid peroxidase (TPO), and transcriptional factor paired box 8 (PAX8) in dedifferentiated thyroid cancer cells (WRO 82-1 and dFTC-133). Furthermore, nevirapine also enhanced radioiodide uptake significantly both in vitro and in vivo, and inhibited the growth of xenograft tumors. Nevirapine might improve radioiodine sensitivity via the activation of TSHR/cAMP/CREB/PAX8 signaling pathway. This study demonstrates that nevirapine could be potentially used to improve radioiodine therapeutic efficacy in dedifferentiated thyroid cancer patients.

Role of coenzymes in cancer metabolism

Cancer is a heterogeneous set of diseases characterized by the rewiring of cellular signaling and the reprogramming of metabolic pathways to sustain growth and proliferation. In past decades, studies were focused primarily on the genetic complexity of cancer. Recently, increasing number of studies have discovered several mutations among metabolic enzymes in different tumor cells. Most of the enzymes are regulated by coenzymes, organic cofactors, that function as intermediate carrier of electrons or functional groups that are transferred during the reaction. However, the precise role of cofactors is not well elucidated. In this review, we discuss several metabolic enzymes associated to cancer metabolism rewiring, whose inhibition may represent a therapeutic target. Such enzymes, upon expression or inhibition, may impact also the coenzymes levels, but only in few cases, it was possible to direct correlate coenzymes changes with a specific enzyme. In addition, we also summarize an up-to-date information on biological role of some coenzymes, preclinical and clinical studies, that have been carried out in various cancers and their outputs.

The role of Slit2 as a tumor suppressor in thyroid cancer

Slits, representative axon guidance molecules, and their Roundabout (Robo) transmembrane receptors play roles in the progression of many cancers. We investigated the effects of Slit2 on the proliferation, migration, and invasion of thyroid cancer cells, and on the prognosis of papillary thyroid cancer (PTC). Slit2 overexpression inhibited the proliferation, migration and invasion of thyroid cancer cells by inhibiting transcriptional activity of beta-catenin and regulating Rho GTPase activity. Slit2 knockdown activated the migration and invasion of thyroid cancer cells and transcriptional activity of beta-catenin. Fragment Slit2 treatment inhibited thyroid cancer cell proliferation in a dose dependent manner, and also inhibited migration and invasion. When we evaluated the protein expression of Slit2 in PTCs, 24 of 160 PTCs (15%) were negative for Slit2 protein expression and these patients had significantly increased risk of cervical lymph node metastasis (P < 0.001), distant metastasis (P < 0.001) and recurrence of PTC (P < 0.001). Our findings suggest a role for Slit2 as a tumor suppressor, and also as a novel prognostic and potential therapeutic target for thyroid cancer.

Anti-cancer activity of myricetin against human papillary thyroid cancer cells involves mitochondrial dysfunction-mediated apoptosis

Thyroid cancer is the most common endocrine malignancy and can range in severity from relatively slow-growing occult differentiated thyroid cancer to uniformly aggressive and fatal anaplastic thyroid cancer. A subset of patients with papillary thyroid cancer present with aggressive disease that is refractory to conventional treatment. Myricetin is a flavonol compound found in a variety of berries as well as walnuts and herbs. Previous studies have demonstrated that myricetin exhibits anti-cancer activity against several tumor types. However, an anti-cancer effect of myricetin against human papillary thyroid cancer (HPTC) cells has not been established. The present investigation was undertaken to gain insights into the molecular mechanism of the anti-cancer activity of myricetin against HPTC cells. We examined the cytotoxicity, DNA damaging, and cell cycle arresting activities of myricetin using SNU-790 HPTC cells. We found that myricetin exhibited cytotoxicity and induced DNA condensation in SNU-790 HPTC cells in a dose-dependent manner. Moreover, myricetin up-regulated the activation of caspase cascades and the Bax:Bcl-2 expression ratio. In addition, myricetin induced the release of apoptosis-inducing factor (AIF) and altered the mitochondrial membrane potential. Our results suggest that myricetin induces the death of SNU-790 HPTC cells and thus may prove useful in the development of therapeutic agents for human thyroid cancers.

Alpha lipoic acid inhibits proliferation and epithelial mesenchymal transition of thyroid cancer cells

The naturally occurring short-chain fatty acid, α-lipoic acid (ALA) is a powerful antioxidant which is clinically used for treatment of diabetic neuropathy. Recent studies suggested the possibility of ALA as a potential anti-cancer agent, because it could activate adenosine monophosphate activated protein kinase (AMPK) and inhibit transforming growth factor-β (TGFβ) pathway. In this study, we evaluate the effects of ALA on thyroid cancer cell proliferation, migration and invasion. We performed in vitro cell proliferation analysis using BCPAP, HTH-83, CAL-62 and FTC-133 cells. ALA suppressed thyroid cancer cell proliferation through activation of AMPK and subsequent down-regulation of mammalian target of rapamycin (mTOR)-S6 signaling pathway. Low-dose ALA, which had minimal effects on cell proliferation, also decreased cell migration and invasion of BCPAP, CAL-62 and HTH-83 cells. ALA inhibited epithelial mesenchymal transition (EMT) evidently by increase of E-cadherin and decreases of activated β-catenin, vimentin, snail, and twist in these cells. ALA suppressed TGFβ production and inhibited induction of p-Smad2 and twist by TGFβ1 or TGFβ2. These findings indicate that ALA reduces cancer cell migration and invasion through suppression of TGFβ production and inhibition of TGFβ signaling pathways in thyroid cancer cells. ALA also significantly suppressed tumor growth in mouse xenograft model using BCPAP and FTC-133 cells. This is the first study to show anti-cancer effect of ALA on thyroid cancer cells. ALA could be a potential therapeutic agent for treatment of advanced thyroid cancer, possibly as an adjuvant therapy with other systemic therapeutic agents.