Cancer preventive activities of green tea and its main constituent, (-)-epigallocatechin gallate (EGCG) have been extensively studied by scientists all over the world. Since 1983, we have studied the ...cancer chemopreventive effects of EGCG as well as green tea extract and underlying molecular mechanisms. The first part of this review summarizes ground-breaking topics with EGCG and green tea extract: 1) Delayed cancer onset as revealed by a 10-year prospective cohort study, 2) Prevention of colorectal adenoma recurrence by a double-blind randomized clinical phase II trial, 3) Inhibition of metastasis of B16 melanoma cells to the lungs of mice, 4) Increase in the average value of Young's moduli, i.e., cell stiffness, for human lung cancer cell lines and inhibition of cell motility and 5) Synergistic enhancement of anticancer activity against human cancer cell lines with the combination of EGCG and anticancer compounds. In the second part, we became interested in cancer stem cells (CSCs). 1) Cancer stem cells in mouse skin carcinogenesis by way of introduction, after which we discuss two subjects from our review on human CSCs reported by other investigators gathered from a search of PubMed, 2) Expression of stemness markers of human CSCs compared with their parental cells, and 3) EGCG decreases or increases the expression of mRNA and protein in human CSCs. On this point, EGCG inhibited self-renewal and expression of pluripotency-maintaining transcription factors in human CSCs. Human CSCs are thus a target for cancer prevention and treatment with EGCG and green tea catechins.
Purpose
Our previous experiments show that the main constituent of green-tea catechins, (−)-epigallocatechin gallate (EGCG), completely prevents tumor promotion on mouse skin initiated with ...7,12-dimethylbenz(a)anthracene followed by okadaic acid and that EGCG and green tea extract prevent cancer development in a wide range of target organs in rodents. Therefore, we focused our attention on human cancer stem cells (CSCs) as targets of cancer prevention and treatment with EGCG.
Methods
The numerous reports concerning anticancer activity of EGCG against human CSCs enriched from cancer cell lines were gathered from a search of PubMed, and we hope our review of the literatures will provide a broad selection for the effects of EGCG on various human CSCs.
Results
Based on our theoretical study, we discuss the findings as follows: (1) Compared with the parental cells, human CSCs express increased levels of the stemness markers Nanog, Oct4, Sox2, CD44, CD133, as well as the EMT markers, Twist, Snail, vimentin, and also aldehyde dehydrogenase. They showed decreased levels of E-cadherin and cyclin D1. (2) EGCG inhibits the transcription and translation of genes encoding stemness markers, indicating that EGCG generally inhibits the self-renewal of CSCs. (3) EGCG inhibits the expression of the epithelial-mesenchymal transition phenotypes of human CSCs. (4) The inhibition of EGCG of the stemness of CSCs was weaker compared with parental cells. (5) The weak inhibitory activity of EGCG increased synergistically in combination with anticancer drugs.
Conclusions
Green tea prevents human cancer, and the combination of EGCG and anticancer drugs confers cancer treatment with tissue-agnostic efficacy.
Purpose
The okadaic acid class of tumor promoters, which are inhibitors of protein phosphatases 1 and 2A (PP1 and PP2A), induced tumor promotion in mouse skin, rat glandular stomach, and rat liver. ...Endogenous protein inhibitors of PP2A, SET and CIP2A, were up-regulated in various human cancers, so it is vital to review the essential mechanisms of tumor promotion by the okadaic acid class compounds, together with cancer progression by SET and CIP2A in humans.
Results and discussion
The first part of this review introduces the okadaic acid class compounds and the mechanism of tumor promotion: (1) inhibition of PP1 and PP2A activities of the okadaic acid class compounds; (2) some topics of tumor promotion; (3)
TNF-α
gene expression as a central mediator in tumor promotion; (4) exposure to the okadaic acid class of tumor promoters in relation to human cancer. The second part emphasizes the overexpression of SET and CIP2A in cancer progression, and the anticancer activity of SET antagonists as follows: (5) isolation and characterization of SET; (6) isolation and characterization of CIP2A; (7) progression of leukemia with SET; (8) progression of breast cancer with SET and CIP2A; (9) progression of lung cancer with SET; (10) anti-carcinogenic effects of SET antagonists OP449 and FTY720; and also (11) TNF-α-inducing protein of
Helicobacter pylori
, which is a clinical example of the okadaic acid pathway.
Conclusions
The overexpression of endogenous protein inhibitors of PP2A, SET and CIP2A, is tightly linked to the progression of various human cancers, as well as Alzheimer’s disease.
To explore a more effective treatment for newly diagnosed stage IV, relapsed, or refractory extranodal natural killer/T-cell lymphoma, nasal type (ENKL), we conducted a phase II study of the steroid ...(dexamethasone), methotrexate, ifosfamide, L-asparaginase, and etoposide (SMILE) regimen.
Patients with newly diagnosed stage IV, relapsed, or refractory disease and a performance status of 0 to 2 were eligible. Two cycles of SMILE chemotherapy were administered as the protocol treatment. The primary end point was the overall response rate (ORR) after the protocol treatment.
A total of 38 eligible patients were enrolled. The median age was 47 years (range, 16 to 67 years), and the male:female ratio was 21:17. The disease status was newly diagnosed stage IV in 20 patients, first relapse in 14 patients, and primary refractory in four patients. The eligibility was revised to include lymphocyte counts of 500/μL or more because the first two patients died from infections. No treatment-related deaths were observed after the revision. The ORR and complete response rate after two cycles of SMILE chemotherapy were 79% (90% CI, 65% to 89%) and 45%, respectively. In the 28 patients who completed the protocol treatment, 19 underwent hematopoietic stem-cell transplantation. The 1-year overall survival rate was 55% (95% CI, 38% to 69%). Grade 4 neutropenia was observed in 92% of the patients. The most common grade 3 or 4 nonhematologic complication was infection (61%).
SMILE chemotherapy is an effective treatment for newly diagnosed stage IV, relapsed or refractory ENKL. Myelosuppression and infection during the treatment should be carefully managed.
Purpose
Okadaic acid class of tumor promoters are transformed into endogenous protein inhibitors of PP2A, SET, and CIP2A in human cancers. This indicates that inhibition of PP2A activity is a common ...mechanism of cancer progression in humans. It is important to study the roles of SET and CIP2A vis-à-vis their clinical significance on the basis of new information gathered from a search of PubMed.
Results and discussion
The first part of this review introduces the carcinogenic roles of TNF-α and IL-1, which are induced by the okadaic acid class of compounds. The second part describes unique features of SET and CIP2A in cancer progression for several types of human cancer: (1) SET-expressing circulating tumor cells (SET-CTCs) in breast cancer, (2) knockdown of CIP2A and increased PP2A activity in chronic myeloid leukemia, (3) CIP2A and epidermal growth factor receptor (EGFR) activity in erlotinib sensitive- and resistant-non-small cell lung cancer, (4) SET antagonist EMQA plus radiation therapy against hepatocellular carcinoma, (5) PP2A inactivation as a common event in colorectal cancer, (6) prostate cancer susceptibility variants, homeobox transcription factor (
HOXB13
T) and
CIP2A
T, and (7) SET inhibitor OP449 for pre-clinical investigation of pancreatic cancer. In the Discussion, the binding complex of SET is briefly introduced, and overexpression of SET and CIP2A proteins is discussed in relation to age-associated chronic inflammation (inflammaging).
Conclusion
This review establishes the concept that inhibition of PP2A activity is a common mechanism of human cancer progression and activation of PP2A activity leads to effective anticancer therapy.
Adult T-cell leukemia-lymphoma (ATL) is an aggressive hematological malignancy of CD4+ T cells transformed by human T-cell lymphotropic virus-1 (HTLV-1). Most HTLV-1-infected individuals are ...asymptomatic, and only 3% to 5% of carriers develop ATL. Here, we describe the contribution of aberrant DNA methylation to ATL leukemogenesis. HTLV-1-infected T-cells and their uninfected counterparts were separately isolated based on CADM1 and CD7 expression status, and differentially methylated positions (DMPs) specific to HTLV-infected T cells were identified through genome-wide DNA methylation profiling. Accumulation of DNA methylation at hypermethylated DMPs correlated strongly with ATL development and progression. In addition, we identified 22 genes downregulated because of promoter hypermethylation in HTLV-1-infected T cells, including THEMIS, LAIR1, and RNF130, which negatively regulate T-cell receptor (TCR) signaling. Phosphorylation of ZAP-70, a transducer of TCR signaling, was dysregulated in HTLV-1-infected cell lines but was normalized by reexpression of THEMIS. Therefore, we hypothesized that DNA hypermethylation contributes to growth advantages in HTLV-1-infected cells during ATL leukemogenesis. To test this idea, we investigated the anti-ATL activities of OR-1200 and OR-2100 (OR21), novel decitabine (DAC) prodrugs with enhanced oral bioavailability. Both DAC and OR21 inhibited cell growth, accompanied by global DNA hypomethylation, in xenograft tumors established by implantation of HTLV-1-infected cells. OR21 was less hematotoxic than DAC, whereas tumor growth inhibition was almost identical between the 2 compounds, making it suitable for long-term treatment of ATL patient-derived xenograft mice. Our results demonstrate that regional DNA hypermethylation is functionally important for ATL leukemogenesis and an effective therapeutic target.
2-Hydroxypropyl-β-cyclodextrin (HP-β-CyD) is a cyclic oligosaccharide that is widely used as an enabling excipient in pharmaceutical formulations, but also as a cholesterol modifier. HP-β-CyD has ...recently been approved for the treatment of Niemann-Pick Type C disease, a lysosomal lipid storage disorder, and is used in clinical practice. Since cholesterol accumulation and/or dysregulated cholesterol metabolism has been described in various malignancies, including leukemia, we hypothesized that HP-β-CyD itself might have anticancer effects. This study provides evidence that HP-β-CyD inhibits leukemic cell proliferation at physiologically available doses. First, we identified the potency of HP-β-CyD in vitro against various leukemic cell lines derived from acute myeloid leukemia (AML), acute lymphoblastic leukemia and chronic myeloid leukemia (CML). HP-β-CyD treatment reduced intracellular cholesterol resulting in significant leukemic cell growth inhibition through G2/M cell-cycle arrest and apoptosis. Intraperitoneal injection of HP-β-CyD significantly improved survival in leukemia mouse models. Importantly, HP-β-CyD also showed anticancer effects against CML cells expressing a T315I BCR-ABL mutation (that confers resistance to most ABL tyrosine kinase inhibitors), and hypoxia-adapted CML cells that have characteristics of leukemic stem cells. In addition, colony forming ability of human primary AML and CML cells was inhibited by HP-β-CyD. Systemic administration of HP-β-CyD to mice had no significant adverse effects. These data suggest that HP-β-CyD is a promising anticancer agent regardless of disease or cellular characteristics.
Liquid biopsy has become widely applied in clinical medicine along with the progress in innovative technologies, such as next generation sequencing, but the origin of circulating tumor DNA (ctDNA) ...has not yet been precisely established. We reported bimodal peaks of long fragment circulating free DNA (cfDNA) of 5 kb and short fragment cfDNA of 170 bp in patients with advanced lung cancer, and both contained ctDNA. In this paper, we demonstrate that the total amount of cfDNA is higher when patients with lung cancer have extrathoracic metastases, and the amount of long fragment cfDNA is significantly higher in those patients. To investigate the origin of long fragment cfDNA, conditioned media isolated from lung cancer cell lines was fractionated. Long fragment cfDNA was found concomitant with extracellular vesicles (EVs), but short fragment cfDNA was not observed in any fractions. However, in peripheral blood from a metastatic animal model both fragments were detected even with those same lung cancer cell lines. In human plasma samples, long fragment cfDNA was observed in the same fraction as that from conditioned media, and short fragment cfDNA existed in the supernatant after centrifugation at 100,000g. Concentration of ctDNA in the supernatant was two times higher than that in plasma isolated by the conventional procedure. Long fragment cfDNA associated with tumor progression might therefore be released into peripheral blood, and it is possible that the long fragment cfDNA escapes degradation by co-existing with EVs. Examination of the biological characteristics of long fragment cfDNA is a logical subject of further investigation.
Carbapenemase-producing Enterobacteriaceae (CPE) is a major global health threat, and development of rapid detection methods is desired. Here, we established a cost-effective and relatively rapid CPE ...detection method using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).
We examined 134 CPE strains (IMP-type, NDM-type, VIM-type, KPC-type, OXA-48-like-type, and GES-type) and 107 non-CPE strains, previously confirmed by genetic tests. The proposed MALDI-TOF MS method involves mixing of a carbapenem drug here, the commercially available imipenem (IPM) KB disc and the bacterial strains to be tested, and the consequent drug hydrolysis owing to bacterial carbapenemase activity is confirmed by a waveform spectrum before and after 2 h of the mixing. As metallo-beta-lactamases require zinc in their active site, the false-negatives obtained from our method were cultured in presence of zinc sulfate solution and tested again.
Based on the presence or absence of the IPM (+cyano-4-hydroxy-cinnamic acid)-specific waveform peak near 489.45 m/z (±500 ppm), the detection sensitivity and specificity of our method for CPE were determined to be 94.8% and 91.6%, respectively. Seven false-negatives of IMP-type (4), VIM-type (2), and GES-type (1) were found, of which the IMP- and VIM-types tested positive as CPE after culture with zinc sulfate solution. Thus, the overall detection sensitivity improved to 99.3%.
Our study proposes a new approach for CPE detection using MALDI-TOF MS. Moreover, we propose cultivation of test strains with zinc sulfate solution for efficient detection of IMP-type CPE, not only for MALDI-TOF MS, but also for other detection methods.
Evaluating liver steatosis and fibrosis is important for patients with non-alcoholic fatty liver disease. Although liver biopsy and pathological assessment is the gold standard for these conditions, ...this technique has several disadvantages. The evaluation of steatosis and fibrosis using ultrasound B-mode imaging is qualitative and subjective. The liver stiffness measurement (LSM) and controlled attenuation parameter (CAP) determined using FibroScan are the evidence-based non-invasive measures of liver fibrosis and steatosis, respectively. The LSM and CAP measurements are carried out simultaneously, and the median values of more than ten valid measurements are used to quantify liver fibrosis and steatosis. Here, we demonstrate that the reliability of the LSM depends on the interquartile range to median ratio (IQR/Med), but CAP values do not depend on IQR/Med. In addition, the LSM is affected by inflammation, congestion, and cholestasis in addition to fibrosis, while CAP values are affected by the body mass index in addition to steatosis. We also show that the M probe provides higher LSM values but lower CAP values than the XL probe in the same population. However, there was no statistically significant difference between the diagnostic accuracies of the two probes. These findings are important to understand the reliability of FibroScan measurements and the factors influencing measurement values for all patients.
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