Preventive Effect of Molecular Iodine in Pancreatic Disorders from Hypothyroid Rabbits.

Pancreatic alterations such as inflammation and insulin resistance accompany hypothyroidism. Molecular iodine (I2) exerts antioxidant and differentiation actions in several tissues, and the pancreas is an iodine-uptake tissue. We analyzed the effect of two oral I2 doses on pancreatic disorders in a model of hypothyroidism for 30 days. Adult female rabbits were divided into the following groups: control, moderate oral dose of I2 (0.2 mg/kg, M-I2), high oral dose of I2 (2.0 mg/kg, H-I2), oral dose of methimazole (MMI; 10 mg/kg), MMI + M-I2,, and MMI + H-I2. Moderate or high I2 supplementation did not modify circulating metabolites or pancreatic morphology. The MMI group showed reductions of circulating thyroxine (T4) and triiodothyronine (T3), moderate glucose increments, and significant increases in cholesterol and low-density lipoproteins. Acinar fibrosis, high insulin content, lipoperoxidation, and overexpression of GLUT4 were observed in the pancreas of this group. M-I2 supplementation normalized the T4 and cholesterol, but T3 remained low. Pancreatic alterations were prevented, and nuclear factor erythroid-2-related factor-2 (Nrf2), antioxidant enzymes, and peroxisome proliferator-activated receptor gamma (PPARG) maintained their basal values. In MMI + H-I2, hypothyroidism was avoided, but pancreatic alterations and low PPARG expression remained. In conclusion, M-I2 supplementation reestablishes thyronine synthesis and diminishes pancreatic alterations, possibly related to Nrf2 and PPARG activation.

Protective effects of iodine on rat prostate inflammation induced by sex hormones and on the DU145 prostate cancer cell line treated with TNF.

Molecular iodine (I2) prevents oxidative stress and prostate hyperplasia induced by hyperandrogenism and reduces cell viability in prostate cancer cell lines. Here, we aimed to evaluate the protective effect of I2 and testosterone (T) on hyperestrogenism-induced prostate inflammation. Additionally, the effects of I2 and/or tumor necrosis factor (TNF) on cell viability and interleukin 6 (IL6) secretion were evaluated in a prostate cancer cell line (DU145). We also investigated whether the effects of I2 on viability are peroxisome proliferator-activated receptor gamma (PPARG)-dependent. Castrated (Cx) rats received pellets of either 17ß estradiol (E2) or E2 and T and were treated with I2 (0.05%) in the drinking water for four weeks. The experimental groups were sham, Cx, Cx + E2, Cx + E2+I2, Cx + E2+T, and Cx + E2+T + I2. As expected, inflammation was triggered in the Cx + E2 group (high inflammation score; increase in TNF and transcriptional activity of RELA [nuclear factor-kappa B p65 subunit]), and this effect was diminished in the Cx + E2+T group (medium inflammation score and decrease in TNF). The lowest inflammation score (decrease of TNF and RELA and increase of PPARG) was obtained in the Cx + E2+T + I2 group. In DU145 cells, I2 (400 µM) and TNF (10 ng/ml) additively reduced cell viability, and I2 reduced the production of TNF-stimulated IL6. The PPARG antagonist (GW9662) did not inhibit the effects of I2 on the loss of cell viability. In summary, our data suggest that I2 and T exert a synergistic anti-inflammatory action on the normal prostate, and the interrelationship between I2 and TNF leads to anti-proliferative effects in DU145 cells. PPARG does not seem to participate in the I2-induced cell viability loss in the prostate.

Accuracy and Precision of Iodine Quantification in Subtracted Micro-Computed Tomography: Effect of Reconstruction and Noise Removal Algorithms.

PURPOSE: To evaluate the effect of reconstruction and noise removal algorithms on the accuracy and precision of iodine concentration (CI) quantified with subtracted micro-computed tomography (micro-CT). PROCEDURES: Two reconstruction algorithms were evaluated: a filtered backprojection (FBP) algorithm and a simultaneous iterative reconstruction technique (SIRT) algorithm. A 3D bilateral filter (BF) was used for noise removal. A phantom study evaluated and compared the image quality, and the accuracy and precision of CI in four scenarios: filtered FBP, filtered SIRT, non-filtered FBP, and non-filtered SIRT. In vivo experiments were performed in an animal model of chemically-induced mammary cancer. RESULTS: Linear relationships between the measured and nominal CI values were found for all the scenarios in the phantom study (R2 > 0.95). SIRT significantly improved the accuracy and precision of CI compared to FBP, as given by their lower bias (adj. p-value = 0.0308) and repeatability coefficient (adj. p-value < 0.0001). Noise removal enabled a significant decrease in bias in filtered SIRT images only; non-significant differences were found for the repeatability coefficient. The phantom and in vivo studies showed that CI is a reproducible imaging parameter for all the scenarios (Pearson r > 0.99, p-value < 0.001). The contrast-to-noise ratio showed non-significant differences among the evaluated scenarios in the phantom study, while a significant improvement was found in the in vivo study when SIRT and BF algorithms were used. CONCLUSIONS: SIRT and BF algorithms improved the accuracy and precision of CI compared to FBP and non-filtered images, which encourages their use in subtracted micro-CT imaging.

Neuroendocrine Differentiation of Lung Cancer Cells Impairs the Activation of Antitumor Cytotoxic Responses in Mice.

Lung cancer has the highest mortality among all types of cancer; during its development, cells can acquire neural and endocrine properties that affect tumor progression by releasing several factors, some acting as immunomodulators. Neuroendocrine phenotype correlates with invasiveness, metastasis, and low survival rates. This work evaluated the effect of neuroendocrine differentiation of adenocarcinoma on the mouse immune system. A549 cells were treated with FSK (forskolin) and IBMX (3-Isobutyl-1-methylxanthine) for 96 h to induce neuroendocrine differentiation (NED). Systemic effects were assessed by determining changes in circulating cytokines and immune cells of BALB/c mice immunized with PBS, undifferentiated A549 cells, or neuroendocrine A549NED cells. A549 cells increased circulating monocytes, while CD4+CD8- and CD4+CD8+ T cells increased in mice immunized with neuroendocrine cells. IL-2 and IL-10 increased in mice that received untreated A549 cells, suggesting that the immune system mounts a regulated response against adenocarcinoma, which did not occur with A549NED cells. Cocultures demonstrated the cytotoxic capacity of PBMCs when confronted with A549 cells, while in the presence of neuroendocrine cells they not only were unable to show cytolytic activity, but also lost viability. Neuroendocrine differentiation seems to mount less of an immune response when injected in mice, which may contribute to the poor prognosis of cancer patients affected by this pathology.

Molecular Iodine Supplement Prevents Streptozotocin-Induced Pancreatic Alterations in Mice.

Pancreatitis has been implicated in the development and progression of type 2 diabetes and cancer. The pancreas uptakes molecular iodine (I2), which has anti-inflammatory and antioxidant effects. The present work analyzes whether oral I2 supplementation prevents the pancreatic alterations promoted by low doses of streptozotocin (STZ). CD1 mice (12 weeks old) were divided into the following groups: control; STZ (20 mg/kg/day, i.p. for five days); I2 (0.2 mg/Kg/day in drinking water for 15 days); and combined (STZ + I2). Inflammation (Masson's trichrome and periodic acid-Schiff stain), hyperglycemia, decreased ß-cells and increased α-cells in pancreas were observed in male and female animals with STZ. These animals also showed pancreatic increases in immune cells and inflammation markers as tumor necrosis factor-alpha, transforming growth factor-beta and inducible nitric oxide synthase with a higher amount of activated pancreatic stellate cells (PSCs). The I2 supplement prevented the harmful effect of STZ, maintaining normal pancreatic morphometry and functions. The elevation of the nuclear factor erythroid-2 (Nrf2) and peroxisome proliferator-activated receptor type gamma (PPARγ) contents was associated with the preservation of normal glycemia and lipoperoxidation. In conclusion, a moderated supplement of I2 prevents the deleterious effects of STZ in the pancreas, possibly through antioxidant and antifibrotic mechanisms including Nrf2 and PPARγ activation.

Effects of hypothyroidism on the female pancreas involve the regulation of estrogen receptors.

This study aimed to investigate the impact of short-time hypothyroidism on the expression of aromatase, estrogen receptors (ERα, ß), and GPR30 in the pancreas of female rabbits. The formation of new islets and the expression of insulin, GLUT4, and lactate dehydrogenase (LDH) were also analyzed. This purpose is based on actions that thyroid hormones and estrogens have on ß-cells differentiation, acinar cell function, and insulin secretion. Twelve Chinchilla-breed adult virgin female rabbits were divided into control (n = 6) and hypothyroid (n = 6; methimazole 10 mg/kg for 30 days) groups. In the complete pancreas, expressions of aromatase and estrogen receptors, as well as proinsulin, GLUT4, and LDH were determined by western blot. Characteristics of islets were measured in slices of the pancreas with immunohistochemistry for insulin. Islet and acinar cells express aromatase, ERα, ERß, and GPR30. Hypothyroidism increased the expression of ERα and diminished that for aromatase, ERß, and GPR30 in the pancreas. It also promoted a high number of extra small islets (new islets) and increased the expression of proinsulin and GLUT4 in the pancreas. Our results show that actions of thyroid hormones and estrogens on ß-cells neogenesis, acinar cell function, and synthesis and secretion of insulin are linked. Thus, the effects of hypothyroidism on the pancreas could include summatory actions of thyroid hormones plus estrogens. Our findings indicate the importance of monitoring estrogen levels and actions on the pancreas of hypothyroid women, particularly when serum estrogen concentrations are affected such as menopausal, pregnant, and those with contraceptive use.

Prostate gland as a target organ of thyroid hormones: advances and controversies.

Thyroid hormones (THs) are involved in the development and function of the male reproductive system, but their effects on the prostate have been poorly studied. This work reviews studies related to the interrelationship between the thyroid and the prostate. The information presented here is based upon bibliographic searches in PubMed using the following search terms: prostate combined with thyroid hormone or triiodothyronine, thyroxine, hypothyroidism, hyperthyroidism, or deiodinase. We identified and searched 49 articles directly related to the issue, and discarded studies related to endocrine disruptors. The number of publications has grown in the last 20 years, considering that one of the first studies was published in 1965. This review provides information based on in vitro studies, murine models, and clinical protocols in patients with thyroid disorders. Studies indicate that THs regulate different aspects of growth, metabolism, and prostate pathology, whose global effect depends on total and/or free concentrations of THs in serum, local bioavailability, and the endocrine androgen/thyronine context.

Effects of Molecular Iodine/Chemotherapy in the Immune Component of Breast Cancer Tumoral Microenvironment.

Molecular iodine (I2) induces apoptotic, antiangiogenic, and antiproliferative effects in breast cancer cells. Little is known about its effects on the tumor immune microenvironment. We studied the effect of oral (5 mg/day) I2 supplementation alone (I2) or together with conventional chemotherapy (Cht+I2) on the immune component of breast cancer tumors from a previously published pilot study conducted in Mexico. RNA-seq, I2 and Cht+I2 samples showed significant increases in the expression of Th1 and Th17 pathways. Tumor immune composition determined by deconvolution analysis revealed significant increases in M0 macrophages and B lymphocytes in both I2 groups. Real-time RT-PCR showed that I2 tumors overexpress T-BET (p = 0.019) and interferon-gamma (IFNγ; p = 0.020) and silence tumor growth factor-beta (TGFß; p = 0.049), whereas in Cht+I2 tumors, GATA3 is silenced (p = 0.014). Preliminary methylation analysis shows that I2 activates IFNγ gene promoter (by increasing its unmethylated form) and silences TGFß in Cht+I2. In conclusion, our data showed that I2 supplements induce the activation of the immune response and that when combined with Cht, the Th1 pathways are stimulated. The molecular mechanisms involved in these responses are being analyzed, but preliminary data suggest that methylation/demethylation mechanisms could also participate.

Molecular Iodine/Cyclophosphamide Synergism on Chemoresistant Neuroblastoma Models.

Neuroblastoma (Nb), the most common extracranial tumor in children, exhibited remarkable phenotypic diversity and heterogeneous clinical behavior. Tumors with MYCN overexpression have a worse prognosis. MYCN promotes tumor progression by inducing cell proliferation, de-differentiation, and dysregulated mitochondrial metabolism. Cyclophosphamide (CFF) at minimum effective oral doses (metronomic therapy) exerts beneficial actions on chemoresistant cancers. Molecular iodine (I2) in coadministration with all-trans retinoic acid synergizes apoptosis and cell differentiation in Nb cells. This work analyzes the impact of I2 and CFF on the viability (culture) and tumor progression (xenografts) of Nb chemoresistant SK-N-BE(2) cells. Results showed that both molecules induce dose-response antiproliferative effects, and I2 increases the sensibility of Nb cells to CFF, triggering PPARγ expression and acting as a mitocan in mitochondrial metabolism. In vivo oral I2/metronomic CFF treatments showed significant inhibition in xenograft growth, decreasing proliferation (Survivin) and activating apoptosis signaling (P53, Bax/Bcl-2). In addition, I2 decreased the expression of master markers of malignancy (MYCN, TrkB), vasculature remodeling, and increased differentiation signaling (PPARγ and TrkA). Furthermore, I2 supplementation prevented loss of body weight and hemorrhagic cystitis secondary to CFF in nude mice. These results allow us to propose the I2 supplement in metronomic CFF treatments to increase the effectiveness of chemotherapy and reduce side effects.

Molecular Iodine Has Extrathyroidal Effects as an Antioxidant, Differentiator, and Immunomodulator.

Most investigations of iodine metabolism in humans and animals have focused on its role in thyroid function. However, considerable evidence indicates that iodine could also be implicated in the physiopathology of other organs. We review the literature that shows that molecular iodine (I2) exerts multiple and complex actions on the organs that capture it, not including its effects as part of thyroid hormones. This chemical form of iodine is internalized by a facilitated diffusion system that is evolutionary conserved, and its effects appear to be mediated by a variety of mechanisms and pathways. As an oxidized component, it directly neutralizes free radicals, induces the expression of type II antioxidant enzymes, or inactivates proinflammatory pathways. In neoplastic cells, I2 generates iodolipids with nuclear actions that include the activation of apoptotic pathways and the inhibition of markers related to stem cell maintenance, chemoresistance, and survival. Recently, I2 has been postulated as an immune modulator that depending on the cellular context, can function as an inhibitor or activator of immune responses. We propose that the intake of molecular iodine is increased in adults to at least 1 mg/day in specific pathologies to obtain the potential extrathyroid benefits described in this review.

Micronutrients and Breast Cancer Progression: A Systematic Review.

Epidemiological studies on micronutrient consumption have reported protective associations in the incidence and/or progression of various cancer types. Supplementation with some of these micronutrients has been analyzed, showing chemoprotection, low toxicity, antiproliferation, and the ability to modify epigenetic signatures in various cancer models. This review investigates the reported effects of micronutrient intake or supplementation in breast cancer progression. A PubMed search was conducted with the keywords "micronutrients breast cancer progression", and the results were analyzed. The selected micronutrients were vitamins (C, D, and E), folic acid, metals (Cu, Fe, Se, and Zn), fatty acids, polyphenols, and iodine. The majority of in vitro models showed antiproliferative, cell-cycle arrest, and antimetastatic effects for almost all the micronutrients analyzed, but these effects do not reflect animal or human studies. Only one clinical trial with vitamin D and one pilot study with molecular iodine showed favorable overall survival and disease-free interval.

Molecular iodine synergized and sensitized neuroblastoma cells to the antineoplastic effect of ATRA.

Neuroblastoma (NB) is the most common solid childhood tumor, and all-trans retinoic acid (ATRA) is used as a treatment to decrease minimal residual disease. Molecular iodine (I2) induces differentiation and/or apoptosis in several neoplastic cells through activation of PPARγ nuclear receptors. Here, we analyzed whether the coadministration of I2 and ATRA increases the efficacy of NB treatment. ATRA-sensitive (SH-SY5Y), partially-sensitive (SK-N-BE(2)), and non-sensitive (SK-N-AS) NB cells were used to analyze the effect of I2 and ATRA in vitro and in xenografts (Foxn1 nu/nu mice), exploring actions on cellular viability, differentiation, and molecular responses. In the SH-SY5Y cells, 200 µM I2 caused a 100-fold (0.01 µM) reduction in the antiproliferative dose of ATRA and promoted neurite extension and neural marker expression (tyrosine hydroxylase (TH) and tyrosine kinase receptor alpha (Trk-A)). In SK-N-AS, the I2 supplement sensitized these cells to 0.1 µM ATRA, increasing the ATRA-receptor (RARα) and PPARγ expression, and decreasing the Survivin expression. The I2 supplement increased the mitochondrial membrane potential in SK-N-AS suggesting the participation of mitochondrial-mediated mechanisms involved in the sensibilization to ATRA. In vivo, oral I2 supplementation (0.025%) synergized the antitumor effect of ATRA (1.5 mg/kg BW) and prevented side effects (body weight loss and diarrhea episodes). The immunohistochemical analysis showed that I2 supplementation decreased the intratumoral vasculature (CD34). We suggest that the I2 + ATRA combination should be studied in preclinical and clinical trials to evaluate its potential adjuvant effect in addition to conventional treatments.

A rise in T3/T4 ratio reduces the growth of prostate tumors in a murine model.

Thyroxine (T4) promotes cell proliferation and tumor growth in prostate cancer models, but it is unknown if the increase in the triiodothyronine (T3)/T4 ratio could attenuate prostate tumor development. We assessed T3 effects on thyroid response, histology, proliferation, and apoptosis in the prostate of wild-type (WT) and TRAMP (transgenic adenocarcinoma of the mouse prostate) mice. Physiological doses of T3 were administered in the drinking water (2.5, 5 and 15 µg/100 g body weight) for 6 weeks. None of the doses modified the body weight or serum levels of testosterone, but all of them reduced serum T4 levels by 50%, and the highest dose increased the T3/T4 ratio in TRAMP. In WT, the highest dose of T3 decreased cyclin D1 levels (immunohistochemistry) but did not modify prostate weight or alter the epithelial morphology. In TRAMP, this dose reduced tumor growth by antiproliferative mechanisms independent of apoptosis, but it did not modify the intraluminal or fibromuscular invasion of tumors. In vitro, in the LNCaP prostate cancer cell line, we found that both T3 and T4 increased the number of viable cells (Trypan blue assay), and only T4 response was fully blocked in the presence of an integrin-binding inhibitor peptide (RGD, arginine-glycine-aspartate). In summary, our data show that the prostate was highly sensitive to physiological T3 doses and suggest that in vivo, an increase in the T3/T4 ratio could be associated with the reduced weight of prostate tumors. Longitudinal studies are required to understand the role of thyroid hormones in prostate cancer progression.

Shock Wave Application Increases the Antineoplastic Effect of Molecular Iodine Supplement in Breast Cancer Xenografts.

We evaluated the effect of oral molecular iodine supplementation and shock wave application under three different conditions on human MDA-MB231 cancer cell xenografts. After tumor volume reached 1 cm3, mice were randomly assigned to groups and treated for 3 weeks. The results revealed that high-dose shock wave treatment (150 shock waves at a pressure of 21.7 MPa, SW150/21.7) generated tissue lesions without decreasing tumor growth, canceled the antineoplastic action of iodine and promoted pro-tumor conditions (increased hypoxia-induced factor [HIF] and vascular endothelial growth factor [VEGF]). In contrast, moderate (SW35/21.7) and low (SW35/9.9) doses of shock waves had significant antineoplastic effects and, in combination with iodine supplement, attenuated the aggressiveness of these cells by decreasing expression of the markers of stem cells (CD44 and Sox2) and invasion (HIF and VEGF). These results allow us to propose the combination of shock waves and iodine as a possible adjuvant in breast cancer therapy.

Adjuvant Effect of Molecular Iodine in Conventional Chemotherapy for Breast Cancer. Randomized Pilot Study.

This study analyzes an oral supplement of molecular iodine (I2), alone and in combination with the neoadjuvant therapy 5-fluorouracil/epirubicin/cyclophosphamide or taxotere/epirubicin (FEC/TE) in women with Early (stage II) and Advanced (stage III) breast cancer. In the Early group, 30 women were treated with I2 (5 mg/day) or placebo (colored water) for 7-35 days before surgery. For the Advanced group, 30 patients received I2 or placebo, along with FEC/TE treatment. After surgery, all patients received FEC/TE + I2 for 170 days. I2 supplementation showed a significant attenuation of the side effects and an absence of tumor chemoresistance. The control, I2, FEC/TE, and FEC/TE + I2 groups exhibited response rates of 0, 33%, 73%, and 100%, respectively, and a pathologic complete response of 18%, and 36% in the last two groups. Five-year disease-free survival rate was significantly higher in patients treated with the I2 supplement before and after surgery compared to those receiving the supplement only after surgery (82% versus 46%). I2-treated tumors exhibit less invasive potential, and significant increases in apoptosis, estrogen receptor expression, and immune cell infiltration. Transcriptomic analysis indicated activation of the antitumoral immune response. The results led us to register a phase III clinical trial to analyze chemotherapy + I2 treatment for advanced breast cancer.

Molecular iodine exerts antineoplastic effects by diminishing proliferation and invasive potential and activating the immune response in mammary cancer xenografts.

BACKGROUND: The immune system is a crucial component in cancer progression or regression. Molecular iodine (I2) exerts significant antineoplastic effects, acting as a differentiation inductor and immune modulator, but its effects in antitumor immune response are not elucidated. METHODS: The present work analyzed the effect of I2 in human breast cancer cell lines with low (MCF-7) and high (MDA-MB231) metastatic potential under both in vitro (cell proliferation and invasion assay) and in vivo (xenografts of athymic nude mice) conditions. RESULTS: In vitro analysis showed that the 200 µM I2 supplement decreases the proliferation rate in both cell lines and diminishes the epithelial-mesenchymal transition (EMT) profile and the invasive capacity in MDA-MB231. In immunosuppressed mice, the I2 supplement impairs implantation (incidence), tumoral growth, and proliferation of both types of cells. Xenografts of the animals treated with I2 decrease the expression of invasion markers like CD44, vimentin, urokinase plasminogen activator and its receptor, and vascular endothelial growth factor; and increase peroxisome proliferator-activated receptor gamma. Moreover, in mice with xenografts, the I2 supplement increases the circulating level of leukocytes and the number of intratumoral infiltrating lymphocytes, some of them activated as CD8+, suggesting the activation of antitumor immune responses. CONCLUSIONS: I2 decreases the invasive potential of a triple negative basal cancer cell line, and under in vivo conditions the oral supplement of this halogen activates the antitumor immune response, preventing progression of xenografts from laminal and basal mammary cancer cells. These effects allow us to propose iodine supplementation as a possible adjuvant in breast cancer therapy.

Molecular iodine inhibits the expression of stemness markers on cancer stem-like cells of established cell lines derived from cervical cancer.

BACKGROUND: Cancer stem cells (CSC) are characterized by deregulated self-renewal, tumorigenicity, metastatic potential, aberrant stemness signaling pathways, resistance to conventional therapy, and the ability to give rise to a progeny of proliferating cells that constitute the bulk of tumors. Targeting CSC will provide novel treatments for cancer. Different investigations have focused on developing complementary approaches that involve natural compounds that decrease chemo-resistance and reduce the side effects of conventional therapies. Since, it has been reported that molecular iodine (I2) exhibits antineoplastic effects and decreases tumor progression in some cancer models, we evaluated the potential effect of I2 on cell cultures enriched in cervical cancer stem-like cells. METHODS: HeLa and SiHa cervical cancer cells were treated with 200uM I2 for 24 h. After time, cells were cultured in CSC-conditioned medium (cervospheres) and viability assays were performed. Following, tumorigenic capabilities in cervospheres treated with I2 were evaluated in NOD/SCID mice. HeLa monolayer cells untreated and their respective cervosphere cells treated or untreated with 200 µM of I2 for 24 h were xenotransplanted subcutaneously at different amounts and mice were monitored for at least 2 months. RESULTS: In the present study, monolayer and CSC-enriched cultures (cervospheres) from cervical cancer-derived cell lines, HeLa and SiHa, showed that 200uM I2 supplementation inhibits proliferation of both and decreased their tumorigenic capacity, in vivo. This antineoplastic effect of I2 was accompanied by diminished expression of stemness markers including CD49f, CK17, OCT-4, NANOG, SOX2, and KLF4, as well as increased expression and activation of PPARγ receptors. CONCLUSIONS: All this data led us to suggest a clinical potential use of I2 for targeting CSC and improve current treatments against cervical cancer.

Molecular iodine/doxorubicin neoadjuvant treatment impair invasive capacity and attenuate side effect in canine mammary cancer.

BACKGROUND: Mammary cancer has a high incidence in canines and is an excellent model of spontaneous carcinogenesis. Molecular iodine (I2) exerts antineoplastic effects on different cancer cells activating re-differentiation pathways. In co-administration with anthracyclines, I2 impairs chemoresistance installation and prevents the severity of side effects generated by these antineoplastic drugs. This study is a random and double-blind protocol that analyzes the impact of I2 (10 mg/day) in two administration schemes of Doxorubicin (DOX; 30 mg/m2) in 27 canine patients with cancer of the mammary gland. The standard scheme (sDOX) includes four cycles of DOX administered intravenously for 20 min every 21 days, while the modified scheme (mDOX) consists of more frequent chemotherapy (four cycles every 15 days) with slow infusion (60 min). In both schemes, I2 or placebo (colored water) was supplemented daily throughout the treatment. RESULTS: mDOX attenuated the severity of adverse events (VCOG-CTCAE) in comparison with the sDOX group. The overall tumor response rate (RECIST criteria) for all dogs was 18% (interval of reduction 48-125%), and no significant difference was found between groups. I2 supplementation enhances the antineoplastic effect in mDOX, exhibiting a significant decrease in the tumor epithelial fraction, diminished expression of chemoresistance (MDR1 and Survivin) and invasion (uPA) markers and enhanced expression of the differentiation factor known as peroxisome proliferator-activated receptors type gamma (PPARγ). Significant tumor lymphocytic infiltration was also observed in both I2-supplemented groups. The ten-month survival analysis showed that the entire I2 supplementation (before and after surgery) induced 67-73% of disease-free survival, whereas supplementation in the last period (only after surgery) produced 50% in both schemes. CONCLUSIONS: The mDOX+I2 scheme improves the therapeutic outcome, diminishes the invasive capacity, attenuates the adverse events and increases disease-free survival. These data led us to propose mDOX+I2 as an effective treatment for canine mammary cancer.

Iodine prevents the increase of testosterone-induced oxidative stress in a model of rat prostatic hyperplasia.

Oxidative stress and inflammation are involved in the development and/or progression of benign prostatic hyperplasia (BPH). Molecular iodine (I2) induces antiproliferative and apoptotic effects in prostate cancer cells, but it is unknown if I2 regulates oxidative stress in the normal and/or tumoral prostate. The purpose of this study was to analyze the effects of I2 and celecoxib (Cxb) on oxidative stress and inflammation in a model of prostatic hyperplasia. Cxb was used as positive control of cyclooxygenase-2 (COX-2) inhibition. Prostatic hyperplasia was induced in male Wistar rats (170g) with testosterone (5mg/kg/week, for three weeks). One week before hyperplasia induction, I2 (25mg/day/rat) or Cxb (1.25mg/day/rat) was supplied for four weeks in the drinking water. Prostatic hyperplasia was evaluated by histological analysis, DNA content, and/or proliferating cell nuclear antigen (PCNA) expression. Lipoperoxidation (malondialdehyde) and nitrite (NO2-) levels were analyzed by colorimetric methods, while nitric oxide synthase (NOS), COX, and myeloperoxidase (MPO) enzymes were analyzed using RT-PCR, immunoblotting, and/or enzymatic assays. Levels of 15-F2t-isoprostanes, prostaglandins (PGE2), leukotrienes (LTB4), and tumor necrosis factor alpha (TNFα) were measured by ELISA. Control testosterone-treated animals exhibited hyperplasia in the dorsolateral prostate, as well as increments in almost all oxidative parameters except for COX-1, TNFα, or MPO. I2 and Cxb prevented epithelial hyperplasia (DNA content) and oxidative stress induction generated by testosterone in almost the same intensity, and the minimum I2 dose required was 2.5mg/rat. The antioxidant capacity of I2 was also analyzed in a cell-free system, showing that this element inhibited the conversion of nitrate (NO3-) to NO2-. I2 did not modify the prostatic oxidative state in testosterone untreated rats. In summary, our data showed that antiproliferative and antioxidant effects of I2 involve the inhibition of NOS and the COX-2 pathway. Further studies are necessary to analyze the therapeutic and/or adjuvant effects of I2 with first-line medications used to treat BPH.

Molecular iodine impairs chemoresistance mechanisms, enhances doxorubicin retention and induces downregulation of the CD44+/CD24+ and E-cadherin+/vimentin+ subpopulations in MCF-7 cells resistant to low doses of doxorubicin.

One of the most dreaded clinical events for an oncology patient is resistance to treatment. Chemoresistance is a complex phenomenon based on alterations in apoptosis, the cell cycle and drug metabolism, and it correlates with the cancer stem cell phenotype and/or epithelial-mesenchymal transition. Molecular iodine (I2) exerts an antitumor effect on different types of iodine-capturing neoplasms by its oxidant/antioxidant properties and formation of iodolipids. In the present study, wild-type breast carcinoma cells (MCF-7/W) were treated chronically with 10 nM doxorubicin (DOX) to establish a low-dose DOX-resistant mammary cancer model (MCF-7/D). MCF-7/D cells were established after 30 days of treatment when the culture showed a proliferation rate similar to that of MCF-7/W. These DOX-resistant cells also showed increases in p21, Bcl-2 and MDR-1 expression. Supplementation with 200 µM I2 exerted similar effects in both cell lines: it decreased the proliferation rate by ~40%, and I2 co-administration with DOX significantly increased the inhibitory effect (to ~60%) and also increased apoptosis (BAX/Bcl-2 index), principally by inhibiting Bcl-2 expression. The inhibition by I2 + DOX was also accompanied by impaired MDR-1 induction as well as by a significant increase in PPARγ expression. All of these changes could be attributed to enhanced DOX retention and differential down-selection of CD44+/CD24+ and E-cadherin+/vimentin+ subpopulations. I2 + DOX-selected cells showed a weak induction of xenografts in Foxn1nu/nu mice, indicating that the iodine supplements reversed the tumorogenic capacity of the MCF-7/D cells. In conclusion, I2 is able to reduce the drug resistance and invasive capacity of mammary cancer cells exposed to DOX and represents an anti-chemoresistance agent with clinical potential.