• Antitumor effects and mechanisms of Ganoderma extracts and spores oil

      Chen, Chun; Li, Peng; Li, Ye; Yao, Guan; Xu, Jian-Hua; Systems Biology Laboratory, Department of Molecular and Cellular Biology, University of Arizona (SPANDIDOS PUBL LTD, 2016-11)
      Ganoderma lucidum is a popular herbal medicine used in China to promote health. Modern studies have disclosed that the active ingredients of Ganoderma can exhibit several effects, including antitumor effects and immunomodulation. The present study evaluated the antitumor effects of self-prepared Ganoderma extracts and spores oil, and investigated the possible underlying mechanisms by observing the effects of the extracts and oil on topoisomerases and the cell cycle. The results showed that Ganoderma extracts and spores oil presented dose-dependent inhibitory effects on tumor cells. The half maximal inhibitory concentration (IC50) values of Ganoderma extracts on HL60, K562 and SGC-7901 cells for 24 h were 0.44, 0.39 and 0.90 mg/ml, respectively; for Ganoderma spores oil, the IC50 values were 1.13, 2.27 and 6.29 mg/ml, respectively. In the in vivo study, the inhibitory rates of Ganoderma extracts (4 g/kg/d, intragastrically) on S180 and H22 cells were 39.1 and 44.6%, respectively, and for Ganoderma spores oil (1.2 g/kg/d, intragastrically) the inhibitory rates were 30.9 and 44.9%, respectively. Ganoderma extracts and spores oil inhibited the activities of topoisomerase I and II. Ganoderma spores oil was shown block the cell cycle at the transition between the G1 and S phases and induce a marked decrease in cyclin D1 levels in K562 cells, with no significant change in cyclin E level. These results suggest that the Ganoderma extracts and spores oil possessed antitumor effects in the in vitro and in vivo studies. The antitumor mechanisms of the extracts and spores oil were associated with inhibitory effects on topoisomerase I and II activities, and for Ganoderma spores oil, the antitumor effects may also be associated with decreased cyclin D1 levels, thus inducing G1 arrest in the cell cycle.
    • Arsenic‑induced BRCA1 CpG promoter methylation is associated with the downregulation of ERα and resistance to tamoxifen in MCF7 breast cancer cells and mouse mammary tumor xenografts

      Selmin, Ornella I; Donovan, Micah G; Skovan, Bethany; Paine-Murieta, Gillian D; Romagnolo, Donato F; Univ Arizona, Dept Nutr Sci; Univ Arizona, Canc Biol Grad Interdisciplinary Program (SPANDIDOS PUBL LTD, 2019-03-01)
      A significant percentage (similar to 30%) of estrogen receptor- (ER)-positive tumors become refractory to endocrine therapies; however, the mechanisms responsible for this resistance remain largely unknown. Chronic exposure to arsenic through foods and contaminated water has been linked to an increased incidence of several tumors and long-term health complications. Preclinical and population studies have indicated that arsenic exposure may interfere with endocrine regulation and increase the risk of breast tumorigenesis. In this study, we examined the effects of sodium arsenite (NaAsIII) exposure in ER-positive breast cancer cells in vitro and in mammary tumor xenografts. The results revealed that acute (within 4 days) and long-term (10 days to 7 weeks) in vitro exposure to environmentally relevant doses reduced breast cancer 1 (BRCA1) and ER expression associated with the gain of cyclin D1 (CCND1) and folate receptor 1 (FOLR1), and the loss of methylenetetrahydrofolate reductase (MTHFR) expression. Furthermore, long-term exposure to NaAsIII induced the proliferation and compromised the response of MCF7 cells to tamoxifen (TAM). The in vitro exposure to NaAsIII induced BRCA1 CpG methylation associated with the increased recruitment of DNA methyltransferase 1 (DNMT1) and the loss of RNA polymerase II (PolII) at the BRCA1 gene. Xenografts of NaAsIII-preconditioned MCF7 cells (MCF7NaAs(III)) into the mammary fat pads of nude mice produced a larger tumor volume compared to tumors from control MCF7 cells and were more refractory to TAM in association with the reduced expression of BRCA1 and ER, CpG hypermethylation of estrogen receptor 1 (ESR1) and BRCA1, and the increased expression of FOLR1. These cumulative data support the hypothesis that exposure to As-III may contribute to reducing the efficacy of endocrine therapy against ER-positive breast tumors by hampering the expression of ER and BRCA1 via CpG methylation, respectively of ESR1 and BRCA1.
    • Demonstration of a potent RET transcriptional inhibitor for the treatment of medullary thyroid carcinoma based on an ellipticine derivative

      Kumarasamy, Vishnu; Sun, Daekyu; Univ Arizona, Coll Pharm; Univ Arizona, Arizona Canc Ctr; College of Pharmacy, University of Arizona, Tucson, AZ 85719, USA; College of Pharmacy, University of Arizona, Tucson, AZ 85719, USA (SPANDIDOS PUBL LTD, 2017-05-11)
      Dominant-activating mutations in the RET (rear-ranged during transfection) proto-oncogene, which encodes a receptor tyrosine kinase, is often associated with the development of medullary thyroid carcinoma (MTC). The proximal promoter region of the RET gene consists of a guanine-rich sequence containing five runs of three consecutive guanine residues that serve as the binding site for transcriptional factors. As we have recently shown, this stretch of nucleotides in the promoter region is highly dynamic in nature and tend to form non-B DNA secondary structures called G-quadruplexes, which suppress the transcription of the RET gene. In the present study, ellipticine and its derivatives were identified as excellent RET G-quadruplex stabilizing agents. Circular dichroism (CD) spectroscopic studies revealed that the incorporation of a piperidine ring in an ellipticine derivative, NSC311153 improves its binding with the G-quadruplex structure and the stability induced by this compound is more potent than ellipticine. Furthermore, this compound also interfered with the transcriptional mechanism of the RET gene in an MTC derived cell line, TT cells and significantly decreased the endogenous RET protein expression. We demonstrated the specificity of NSC311153 by using papillary thyroid carcinoma (PTC) cells, the TPC1 cell line which lacks the G-quadruplex forming sequence in the promoter region due to chromosomal rearrangement. The RET downregulation selectively suppresses cell proliferation by inhibiting the intracellular Raf/MEK/ERK and PI3K/Akt/mTOR signaling pathways in the TT cells. In the present study, we also showed that the systemic administration of a water soluble NSC311153 analog in a mouse MTC xenograft model inhibited the tumor growth through RET downregulation.
    • Gene targets of sulforaphane in head and neck squamous cell carcinoma

      Hu, Lanlin; Li, Hua; Lee, Eliot D; Grandis, Jennifer R; Bauman, Julie E; Johnson, Daniel E; Univ Arizona, Dept Med Hematol Oncol (SPANDIDOS PUBL LTD, 2019-10-23)
      Patients who have undergone curative‑intent therapy for head and neck squamous cell carcinoma (HNSCC) exhibit a high rate of development of second primary tumors (SPTs), which are frequently lethal. A chemoprevention strategy that prevents SPTs would have a major impact on patient outcomes. Sulforaphane, a naturally‑occurring compound derived from cruciferous vegetables exhibits chemopreventive activity against HNSCC in a preclinical model. The effects of sulforaphane are considered to be mediated, in large part, through increased protein expression of the transcription factor nuclear factor erythroid 2‑related factor 2 (NRF2). Development of sulforaphane chemoprevention for HNSCC would benefit from the identification of robust biomarkers of sulforaphane activity in HNSCC cells and normal mucosal epithelial cells. The present study revealed that sulforaphane potently induces multiple oxidative stress‑associated genes at the RNA and protein levels, in HNSCC cells and Het‑1A cells, a non‑tumorigenic mucosal epithelial cell line. In the present analysis, HMOX1 and HSPA1A were identified as the most highly upregulated genes following sulforaphane treatment, suggesting their potential value as biomarkers to guide clinical trials. Sulforaphane induction of HMOX1 and HSPA1A was validated in vivo in murine tissues. Furthermore, the impact of sulforaphane treatment of HNSCC cells on the expression levels of natural killer group 2D (NKG2D) and DNAX accessory molecule‑1 (DNAM‑1) ligands, which are activators of natural killer (NK) cells, was examined. NRF2‑dependent upregulation of the NKG2D ligand MICA/B was observed. However, only one of the six HNSCC cell lines studied exhibited enhanced sensitivity to NK cell‑mediated killing following sulforaphane treatment, suggesting that this may not be a general mechanism of sulforaphane chemopreventive activity in HNSCC. In summary, the present study identified robust biomarkers of sulforaphane activity in HNSCC and normal tissues, supporting their application in the development of sulforaphane chemoprevention approaches for HNSCC.
    • Radiolabeled methotrexate as a diagnostic agent of inflammatory target sites: A proof-of-concept study

      Papachristou, Maria; Kastis, George; Stavrou, Petros; Xanthopoulos, Stavros; Furenlid, Lars; Datseris, Ioannis; Bouziotis, Penelope; Univ Arizona, Dept Med Imaging, Ctr Gamma Ray Imaging; Department of Nuclear Medicine‑PET/CT, General Hospital of Athens ‘Evaggelismos’, 10676 Athens, Greece; Research Center of Mathematics, Academy of Athens, 11527 Athens, Greece; et al. (SPANDIDOS PUBL LTD, 2017-11-27)
      Methotrexate (MTX), as a pharmaceutical, is frequently used in tumor chemotherapy and is also a part of the established treatment of a number of autoimmune inflammatory disorders. Radiolabeled MTX has been studied as a tumor-diagnostic agent in a number of published studies. In the present study, the potential use of technetium-99m-labelled MTX (Tc-99m-MTX) as a radiotracer was investigated for the identification of inflammatory target sites. The labelling of MTX was carried out via a Tc-99m-gluconate precursor. Evaluation studies included in vitro stability, plasma protein binding assessment, partition-coefficient estimation, in vivo scintigraphic imaging and ex vivo animal experiments in an animal inflammation model. MTX was successfully labelled with Tc-99m, with a radiochemical purity of >95%. Stability was assessed in plasma, where it remained intact up to 85% at 4 h post-incubation, while protein binding of the radiotracer was observed to be similar to 50% at 4 h. These preclinical ex vivo and in vivo studies indicated that Tc-99m-MTX accumulates in inflamed tissue, as well as in the spinal cord, joints and bones; all areas with relatively high remodeling activity. The results are promising, and set the stage for further work on the development and application of Tc-99m-MTX as a radiotracer for inflammation associated with rheumatoid arthritis.
    • Regulation of Fgf15 expression in the intestine by glucocorticoid receptor

      Jia, Kunzhi; Zhang, Danping; Jia, Qi; Zhang, Qing-Yu; Univ Arizona, Coll Pharm, Dept Pharmacol & Toxicol (SPANDIDOS PUBL LTD, 2019-04-01)
      Fibroblast growth factor 15 (FGF15) was previously identified to be highly expressed in the ileum and functions as an endocrine factor to regulate bile acid synthesis in the liver. FGF15 targets its receptor fibroblast growth factor receptor 4 in the liver and serves important roles in energy metabolism, including bile acid homeostasis, glucose metabolism and protein synthesis. The expression of FGF15 is known to be regulated by the transcription factor farnesoid X receptor (FXR). In the present study, reverse transcription-quantitative polymerase chain reaction was used for measuring Fgf15 expression from the animal and tissue culture experiments, and it was identified that dexamethasone, a drug widely used in anti-inflammation therapy, and a classical inducer of glucocorticoid receptor (GR)- and pregnane X receptor (PXR)-target genes, may downregulate Fgf15 expression in the ileum. GR was identified to be highly expressed in the ileum by western blot analysis. Furthermore, it was demonstrated that the downregulation of Fgf15 by dexamethasone is due to the repression of ileal FXR activity via GR; however, not PXR, in the ileum. The present results provide insight for a better understanding of the adverse effects associated with dexamethasone therapy.
    • Salinomycin and its derivatives as potent RET transcriptional inhibitors for the treatment of medullary thyroid carcinoma

      Alqahtani, Tariq; Kumarasamy, Vishnu Muthuraj; Huczyński, Adam; Sun, Daekyu; Univ Arizona, Coll Pharm, Dept Pharmacol & Toxicol; Univ Arizona, BIO5 Inst; Univ Arizona, Arizona Canc Ctr (SPANDIDOS PUBL LTD, 2019-11-20)
      Rearranged during transfection kinase (RET) is a validated molecular target in medullary thyroid cancer (MTC), as activating mutations in RET are often associated with the development of MTC. The present study reports the first preclinical characterization of salinomycin and selected analogs as potent RET transcriptional inhibitors. Reverse transcription‑PCR and immunoblotting revealed that salinomycin profoundly decreased RET expression in the TT human MTC cell line by inhibiting RET transcription. Moreover, salinomycin resulted in remarkable anti‑proliferative activity against MTC that is driven by RET (gain of function mutation) by selectively inhibiting the intracellular PI3K/Akt/mTOR signaling pathway. Also, flow cytometry and fluorescence‑activated cell sorting showed that salinomycin induces G1 phase arrest and apoptosis by reducing the expression of retinoblastoma protein, E2F1, cyclin D and CDK4. The structure‑activity relationship of salinomycin was investigated in this study. Some of the salinomycin derivatives showed the ability to reduce RET expression where others fail to alter RET expression. These results suggest that the RET‑suppressing effect of salinomycin may be largely attributed to disruption of the Wnt pathway, presumably through interference with the ternary LRP6‑Frizzled‑Wnt complex. Furthermore, these findings support the further preclinical evaluation of salinomycin and its analogs as a promising new class of therapeutic agents for the improved treatment of MTC.
    • Two-stage study of lung cancer risk modification by a functional variant in the 3 '-untranslated region of SMAD5 based on the bone morphogenetic protein pathway

      Zhang, Zili; Wang, Jian; Zeng, Xiansheng; Li, Defu; Ding, Mingjing; Guan, Ruijuan; Yuan, Liang; Zhou, Qipeng; Guo, Meihua; Xiong, Mingmei; et al. (SPANDIDOS PUBL LTD, 2018-01-01)
      Increasing evidence supports a key role for the bone morphogenetic protein (BMP) signaling pathway in lung vasculogenesis and angiogenesis. Genetic variations in BMP genes have been found to be correlated with cancer risk. In particular, the mutation in the 3'-untranslated region of BMPs may significantly affect gene function, leading to cancer susceptibility. The aim of the present study was to determine whether genetic variations in the components of the BMP family are associated with lung cancer risk. A total of 314 tag single-nucleotide polymorphisms were identified in 18 genes, which are considered to either compose or regulate BMPs, and their association with lung cancer risk was evaluated in a two-stage case-control study with 4,680 cases and controls. A consistently significant association of SMAD5 rs12719482 with elevated lung cancer risk was observed in the three types of sources of populations (adjusted additive model in the combined population: Odds ratio=1.32, 95% confidence interval: 1.16-1.51). The lung cancer risk statistically significantly increased with the increasing number of variant alleles of SMAD5 rs12719482 in a dose-dependent pattern (P for trend=4.9×10-5). Consistent evidence was identified for a significant interaction between the rs12719482 and cigarette smoking, performed as either a continuous or discrete variable. These findings indicated that SMAD5 rs12719482 may be a possible candidate marker for susceptibility to lung cancer in the Chinese population.