miR-103/107 prolong Wnt/ß-catenin signaling and colorectal cancer stemness by targeting Axin2.

Cancer stemness drives tumor initiation, progression, metastasis, recurrence, and therapy resistance. However, mechanisms that potentiate the acquisition and maintenance of stemness fate of cancer cells remain incompletely understood. Here, we show that miR-103/107 stimulate multiple stem-like features in colorectal cancer, including expression of stem-like markers, appearance of side-population cells, and capabilities in self-renewal, tumor initiation, recurrence, and chemoresistance. Mechanistically, these stemness-promoting functions are mediated by miR-103/107-dependent repression of Axin2, a negative feedback regulator of Wnt/ß-catenin signaling. Through inhibiting Axin2, miR-103/107 trigger a prolonged duration of Wnt/ß-catenin signaling and a sustained induction of Wnt responsive genes. In colorectal cancer patients, miR-103/107 expression correlates inversely with Axin2 expression and a signature of miR-103/107 high and Axin2 low expression profile correlates with poor prognosis. Together, our study identifies a novel function of miR-103/107 in promoting colorectal cancer stemness by targeting Axin2 and elucidates the clinical relevance and prognostic value of this axis in colorectal cancer.

Corrigendum: Tetrac and NDAT Induce Anti-proliferation via Integrin αvß3 in Colorectal Cancers With Different K-RAS Status.

[This corrects the article DOI: 10.3389/fendo.2019.00130.].

Factors associated with completion of childhood immunization in Malawi: a multilevel analysis of the 2015-16 Malawi demographic and health survey.

BACKGROUND: Between 2010 and 2015, the percentage of children 12-23 months of age who received full immunization in Malawi decreased from 81% to 76%, prompting us to investigate the factors associated with completion of childhood immunization in Malawi. METHODS: Using data from the 2015-16 Malawi Demographic and Health Survey, generalized linear mixed models were applied on 3145 children 12-23 months of age nested within 850 communities. Complete immunization was defined as the child having received a Bacillus Calmette-Guerin, three doses of pentavalent vaccine, four doses of oral polio vaccine, three doses of pneumococcal vaccine, two doses of rotavirus vaccine and one dose of measles vaccine before their first birthday. RESULTS: Adjusted multilevel regression showed that children born to mothers with either none or one antenatal care visit (adjusted odds ratio [aOR] 0.56 [95% confidence interval {CI} 0.32 to 0.93]) and whose mothers had no card or no longer had a vaccination card (aOR 0.06 [95% CI 0.04 to 0.07]) were less likely to receive complete immunization. In addition, children from the poorest households (aOR 0.60 [95% CI 0.40 to 0.92]) and who resided in communities with a medium (aOR 0.73 [95% CI 0.53 to 0.98]) or high percentage (aOR 0.73 [95% CI 0.53 to 0.99]) of households that perceived the distance to the nearest health facility as a big problem had reduced odds of achieving complete immunization. Furthermore, the findings showed evidence of clustering effects of childhood complete immunization at the community level. CONCLUSIONS: Our findings show that a series of sociodemographic, health and contextual factors are associated with the completion of childhood vaccination. Therefore interventions that aim at increasing the completion of childhood immunization in Malawi should not only address individual needs, but should also consider contextual factors and the communities addressed in this study.

Tetrac and NDAT Induce Anti-proliferation via Integrin αvß3 in Colorectal Cancers With Different K-RAS Status.

Colorectal cancer is a serious medical problem in Taiwan. New, effective therapeutic approaches are needed. The selection of promising anticancer drugs and the transition from pre-clinical investigations to clinical trials are often challenging. The deaminated thyroid hormone analog (tetraiodothyroacetic acid, tetrac) and its nanoparticulate analog (NDAT) have been shown to have anti-proliferative activity in vitro and in xenograft model of different neoplasms, including colorectal cancers. However, mechanisms involved in tetrac- and NDAT-induced anti-proliferation in colorectal cancers are incompletely understood. We have investigated possible mechanisms of tetrac and NDAT action in colorectal cancer cells, using a perfusion bellows cell culture system that allows efficient, large-scale screening for mechanisms of drug actions on tumor cells. Although integrin αvß3 in K-RAS wild type colorectal cancer HT-29 cells was far less than that in K-RAS mutant HCT116 cells, HT-29 was more sensitive to both tetrac and NDAT. Results also indicate that both tetrac and NDAT bind to tumor cell surface integrin αvß3, and the agents may have different mechanisms of anti-proliferation in colorectal cancer cells. K-RAS status appears to play an important role in drug resistance that may be encountered in treatment with this drug combination.

Enhancement by Nano-Diamino-Tetrac of Antiproliferative Action of Gefitinib on Colorectal Cancer Cells: Mediation by EGFR Sialylation and PI3K Activation.

Drug resistance complicates the clinical use of gefitinib. Tetraiodothyroacetic acid (tetrac) and nano-diamino-tetrac (NDAT) have been shown in vitro and in xenografts to have antiproliferative/angiogenic properties and to potentiate antiproliferative activity of other anticancer agents. In the current study, we investigated the effects of NDAT on the anticancer activities of gefitinib in human colorectal cancer cells. ß-Galactoside α-2,6-sialyltransferase 1 (ST6Gal1) catalyzes EGFR sialylation that is associated with gefitinib resistance in colorectal cancers, and this was also investigated. Gefitinib inhibited cell proliferation of HT-29 cells (K-ras wild-type), and NDAT significantly enhanced the antiproliferative action of gefitinib. Gefitinib inhibited cell proliferation of HCT116 cells (K-ras mutant) only in high concentration, and this was further enhanced by NDAT. NDAT enhancedd gefitinib-induced antiproliferation in gefitinib-resistant colorectal cancer cells by inhibiting ST6Gal1 activity and PI3K activation. Furthermore, NDAT enhanced gefitinib-induced anticancer activity additively in colorectal cancer HCT116 cell xenograft-bearing nude mice. Results suggest that NDAT may have an application with gefitinib as combination colorectal cancer therapy.

Nano-diamino-tetrac (NDAT) inhibits PD-L1 expression which is essential for proliferation in oral cancer cells.

Programmed death-ligand 1 (PD-L1) is a critical regulator to defend tumor cells against immune surveillance. Thyroid hormone has been shown to induce PD-L1 expression in cancer cells. Its nano-particulated analogue, nano-diamino-tetrac (NDAT; Nanotetrac) is an anticancer/anti-angiogenic agent. In the current study, the inhibitory mechanism by which NDAT inhibited PD-L1 mRNA abundance and PD-L1 protein content in oral cancer cells was investigated. NDAT inhibited inducible PD-L1 expression and protein accumulation by the inhibition of activated ERK1/2 and PI3K. Knockdown PD-L1 also inhibited the proliferation of oral cancer cells which suggests that the inhibitory effect of NDAT on PD-L1 expression maybe is one of the critical mechanisms for NDAT-induced anti-proliferative effect in oral cancer cells.

Nano-Diamino-Tetrac (NDAT) Enhances Resveratrol-Induced Antiproliferation by Action on the RRM2 Pathway in Colorectal Cancers.

Cancer resistance to chemotherapeutic agents is a major issue in the management of cancer patients. Overexpression of the ribonucleotide reductase regulatory subunit M2 (RRM2) has been associated with aggressive cancer behavior and chemoresistance. Nano-diamino-tetrac (NDAT) is a nanoparticulate derivative of tetraiodothyroacetic acid (tetrac), which exerts anticancer properties via several mechanisms and downregulates RRM2 gene expression in cancer cells. Resveratrol is a stilbenoid phytoalexin which binds to a specific site on the cell surface integrin αvß3 to trigger cancer cell death via nuclear translocation of COX-2. Here we report that resveratrol paradoxically activates RRM2 gene expression and protein translation in colon cancer cells. This unanticipated effect inhibits resveratrol-induced COX-2 nuclear accumulation. RRM2 downregulation, whether achieved by RNA interference or treatment with NDAT, enhanced resveratrol-induced COX-2 gene expression and nuclear uptake which is essential to integrin αvß3-mediated-resveratrol-induced antiproliferation in cancer cells. Elsewhere, NDAT downregulated resveratrol-induced RRM2 expression in vivo but potentiated the anticancer effect of the stilbene. These findings suggest that RRM2 appears as a cancer cell defense mechanism which can hinder the anticancer effect of the stilbene via the integrin αvß3 axis. Furthermore, the antagonistic effect of RRM2 against resveratrol is counteracted by the administration of NDAT.

Thyroxine inhibits resveratrol-caused apoptosis by PD-L1 in ovarian cancer cells.

Thyroid hormone, l-thyroxine (T4), has been shown to promote ovarian cancer cell proliferation via a receptor on plasma membrane integrin αvß3 and to induce the activation of ERK1/2 and expression of programmed death-ligand 1 (PD-L1) in cancer cells. In contrast, resveratrol binds to integrin αvß3 at a discrete site and induces p53-dependent antiproliferation in malignant neoplastic cells. The mechanism of resveratrol action requires nuclear accumulation of inducible cyclooxygenase (COX)-2 and its complexation with phosphorylated ERK1/2. In this study, we examined the mechanism by which T4 impairs resveratrol-induced antiproliferation in human ovarian cancer cells and found that T4 inhibited resveratrol-induced nuclear accumulation of COX-2. Furthermore, T4 increased expression and cytoplasmic accumulation of PD-L1, which in turn acted to retain inducible COX-2 in the cytoplasm. Knockdown of PD-L1 by small hairpin RNA (shRNA) relieved the inhibitory effect of T4 on resveratrol-induced nuclear accumulation of COX-2- and COX-2/p53-dependent gene expression. Thus, T4 inhibits COX-2-dependent apoptosis in ovarian cancer cells by retaining inducible COX-2 with PD-L1 in the cytoplasm. These findings provide new insights into the antagonizing effect of T4 on resveratrol's anticancer properties.

Thyroid Hormone Promotes ß-Catenin Activation and Cell Proliferation in Colorectal Cancer.

Thyroid hormone status has long been implicated in cancer development. Here we investigated the role of thyroxine (T4) in colorectal cancer cell lines HCT 116 (APC wild type) and HT-29 (APC mutant), as well as the primary cultures of cancer cells derived from patients. Cell proliferation was evaluated with standard assay and proliferation marker expression. ß-Catenin activation was examined according to nuclear ß-catenin accumulation and ß-catenin target gene expression. The results showed that T4 increased colorectal cancer cell proliferation while cell number and viability were elevated by T4 in both established cell lines and primary cells. Moreover, the transcriptions of proliferative genes PCNA, CCND1, and c-Myc were enhanced by T4 in the primary cells. T4 induced nuclear ß-catenin accumulation, as well as high cyclin D1 and c-Myc levels compared to the untreated cells. In addition, the ß-catenin-directed transactivation of CCND1 and c-Myc promoters was also upregulated by T4. CTNNB1 transcription was raised by T4 in HCT 116, but not in HT-29, while the boosted ß-catenin levels were observed in both. Lastly, the T4-mediated gene expression could be averted by the knockdown of ß-catenin. These results suggested that T4 promotes ß-catenin activation and cell proliferation in colorectal cancer, indicating that an applicable therapeutic strategy should be considered.

Tetrac downregulates ß-catenin and HMGA2 to promote the effect of resveratrol in colon cancer.

The molecular pathogenesis of colorectal cancer encompasses the activation of several oncogenic signaling pathways that include the Wnt/ß-catenin pathway and the overexpression of high mobility group protein A2 (HMGA2). Resveratrol - the polyphenolic phytoalexin - binds to integrin αvß3 to induce apoptosis in cancer cells via cyclooxygenase 2 (COX-2) nuclear accumulation and p53-dependent apoptosis. Tetraiodothyroacetic acid (tetrac) is a de-aminated derivative of l-thyroxine (T4), which - in contrast to the parental hormone - impairs cancer cell proliferation. In the current study, we found that tetrac promoted resveratrol-induced anti-proliferation in colon cancer cell lines, in primary cultures of colon cancer cells, and in vivo The mechanisms implicated in this action involved the downregulation of nuclear ß-catenin and HMGA2, which are capable of compromising resveratrol-induced COX-2 nuclear translocation. Silencing of either ß-catenin or HMGA2 promoted resveratrol-induced anti-proliferation and COX-2 nuclear accumulation which is essential for integrin αvß3-mediated-resveratrol-induced apoptosis in cancer cells. Concurrently, tetrac enhanced nuclear abundance of chibby family member 1, the nuclear ß-catenin antagonist, which may further compromise the nuclear ß-catenin-dependent gene expression and proliferation. Taken together, these results suggest that tetrac targets ß-catenin and HMGA2 to promote resveratrol-induced-anti-proliferation in colon cancers, highlighting its potential in anti-cancer combination therapy.

Mechanisms of action of nonpeptide hormones on resveratrol-induced antiproliferation of cancer cells.

Nonpeptide hormones, such as thyroid hormone, dihydrotestosterone, and estrogen, have been shown to stimulate cancer proliferation via different mechanisms. Aside from their cytosolic or membrane-bound receptors, there are receptors on integrin αv ß3 for nonpeptide hormones. Interaction between hormones and integrin αv ß3 can induce signal transduction and eventually stimulate cancer cell proliferation. Resveratrol induces inducible COX-2-dependent antiproliferation via integrin αv ß3 . Resveratrol and hormone-induced signals are both transduced by activated extracellular-regulated kinases 1 and 2 (ERK1/2); however, hormones promote cell proliferation, while resveratrol induces antiproliferation in cancer cells. Hormones inhibit resveratrol-stimulated phosphorylation of p53 on Ser15, resveratrol-induced nuclear COX-2 accumulation, and formation of p53-COX-2 nuclear complexes. Subsequently, hormones impair resveratrol-induced COX-2-/p53-dependent gene expression. The inhibitory effects of hormones on resveratrol action can be blocked by different antagonists of specific nonpeptide hormone receptors but not integrin αv ß3 blockers. Results suggest that nonpeptide hormones inhibit resveratrol-induced antiproliferation in cancer cells downstream of the interaction between ligand and receptor and ERK1/2 activation to interfere with nuclear COX-2 accumulation. Thus, the surface receptor sites for resveratrol and nonpeptide hormones are distinct and can induce discrete ERK1/2-dependent downstream antiproliferation biological activities. It also indicates the complex pathways by which antiproliferation is induced by resveratrol in various physiological hormonal environments. .

Leptin OB3 peptide suppresses leptin-induced signaling and progression in ovarian cancer cells.

BACKGROUND: Obesity and its comorbidities constitute a serious health burden worldwide. Leptin plays an important role in diet control; however, it has a stimulatory potential on cancer cell proliferation. The OB3 peptide, a synthetic peptide, was shown to be more active than leptin in regulating metabolism but with no mitogenic effects in cancer cells. METHODS: In this study, we investigated the proliferative effects, gene expressions and signaling pathways modulated by leptin and OB3 in human ovarian cancer cells. In addition, an animal study was performed. RESULTS: Leptin, but not OB3, induced the proliferation of ovarian cancer cells. Interestingly, OB3 blocked the leptin-induced proliferative effect when it was co-applied with leptin. Both leptin and OB3 activated the phosphatidylinositol-3-kinase (PI3K) signal transduction pathway. In addition, leptin stimulated the phosphorylation of signal transducer and activator of transcription-3 (STAT3) Tyr-705 as well as estrogen receptor (ER)α, and the expression of ERα-responsive genes. Interestingly, all leptin-induced signal activation and gene expressions were blocked by the co-incubation with OB3 and the inhibition of extracellular signal-regulated kinase (ERK)1/2. Coincidently, leptin, but not OB3, increased circulating levels of follicle-stimulating hormone (FSH) which is known to play important roles in the initiation and proliferation of ovarian cancer cells. CONCLUSIONS: In summary, our findings suggest that the OB3 peptide may prevent leptin-induced ovarian cancer initiation and progression by disrupting leptin-induced proliferative signals via STAT3 phosphorylation and ERα activation. Therefore, the OB3 peptide is a potential anticancer agent that might be employed to prevent leptin-induced cancers in obese people.

Actions of l-thyroxine and Nano-diamino-tetrac (Nanotetrac) on PD-L1 in cancer cells.

The PD-1 (programmed death-1)/PD-L1 (PD-ligand 1) checkpoint is a critical regulator of activated T cell-cancer cell interactions, defending tumor cells against immune destruction. Nano-diamino-tetrac (NDAT; Nanotetrac) is an anticancer/anti-angiogenic agent targeted to the thyroid hormone-tetrac receptor on the extracellular domain of integrin αvß3. NDAT inhibits the cancer cell PI3-K and MAPK signal transduction pathways that are critical to PD-L1 gene expression. We examined actions in vitro of thyroid hormone (l-thyroxine, T4) and NDAT on PD-L1 mRNA abundance (qPCR) and PD-L1 protein content in human breast cancer (MDA-MB-231) cells and colon carcinoma (HCT116 and HT-29) cells. In MDA-MB-231 cells, a physiological concentration of T4 (10-7M total; 10-10M free hormone) stimulated PD-L1 gene expression by 38% and increased PD-L1 protein by 2.7-fold (p<0.05, all changes). NDAT (10-7M) reduced PD-L1 in T4-exposed cells by 21% (mRNA) and 39% (protein) (p<0.05, all changes). In HCT116 cells, T4 enhanced PD-L1 gene expression by 17% and protein content by 24% (p<0.05). NDAT reduced basal PD-L1 mRNA by 35% and protein by 31% and in T4-treated cells lowered mRNA by 33% and protein by 66%. In HT-29 cells, T4 increased PD-L1 mRNA by 62% and protein by 27%. NDAT lowered basal and T4-stimulated responses in PD-L1 mRNA and protein by 35-40% (p<0.05). Activation of ERK1/2 was involved in T4-induced PD-L1 accumulation. We propose that, by a nongenomic mechanism, endogenous T4 may clinically support activity of the defensive PD-1/PD-L1 checkpoint in tumor cells. NDAT non-immunologically suppresses basal and T4-induced PD-L1 gene expression and protein accumulation in cancer cells.

Overview of Transforming Growth Factor ß Superfamily Involvement in Glioblastoma Initiation and Progression.

Glioblastoma, also known as glioblastoma multiforme (GBM), is the most aggressive of human brain tumors and has a stunning progression with a mean survival of one year from the date of diagnosis. High cell proliferation, angiogenesis and/or necrosis are histopathological features of this cancer, which has no efficient curative therapy. This aggressiveness is associated with particular heterogeneity of the tumor featuring multiple genetic and epigenetic alterations, but also with implications of aberrant signaling driven by growth factors. The transforming growth factor ß (TGFß) superfamily is a large group of structurally related proteins including TGFß subfamily members Nodal, Activin, Lefty, bone morphogenetic proteins (BMPs) and growth and differentiation factor (GDF). It is involved in important biological functions including morphogenesis, embryonic development, adult stem cell differentiation, immune regulation, wound healing and inflammation. This superfamily is also considered to impact on cancer biology including that of GBM, with various effects depending on the member. The TGFß subfamily, in particular, is overexpressed in some GBM types which exhibit aggressive phenotypes. This subfamily impairs anti-cancer immune responses in several ways, including immune cells inhibition and major histocompatibility (MHC) class I and II abolishment. It promotes GBM angiogenesis by inducing angiogenic factors such as vascular endothelial growth factor (VEGF), plasminogen activator inhibitor (PAI-I) and insulin- like growth factor-binding protein 7 (IGFBP7), contributes to GBM progression by inducing metalloproteinases (MMPs), "pro-neoplastic" integrins (αvß3, α5ß1) and GBM initiating cells (GICs) as well as inducing a GBM mesenchymal phenotype. Equally, Nodal promotes GICs, induces cancer metabolic switch and supports GBM cell proliferation, but is negatively regulated by Lefty. Activin promotes GBM cell proliferation while GDF yields immune-escape function. On the other hand, BMPs target GICS and induce differentiation and sensitivity to chemotherapy. This multifaceted involvement of this superfamily in GBM necessitates different strategies in anti-cancer therapy. While suppressing the TGFß subfamily yields advantageous results, enhancing BMPs production is also beneficial.