NEOPLASTIC TRANSFORMATION OF HUMAN EMBRYONIC NASOPHARYNGEAL EPITHELIAL CELLS INDUCED BY N,N'-DINITROSOPIPERAZINE (DNP) IN VITRO

This experiment is the first report on N, N'-dini-trosopiperazine (DNF)-induced neoplastic transformation of human embryonic nasopharyngeal (HENPE) cells. The transformed cells showed a prolonged life span, anchorage independent growth, chromosome aberration, tumorigenicity and an altered cell morphological appearance. The results demonstrated that DNP was able to induce not only nasopharyngeal carcinoma (NPC) of rats in vivo, but also neoplastic transformation of HENPE cells in vitro.

Radiobiological characteristics of cancer stem cells from esophageal cancer cell lines

AIM: To study the cancer stem cell population in esophageal cancer cell lines KYSE-150 and TE-1 and identify whether the resulting stem-like spheroid cells display cancer stem cells and radiation resistance characteristics.

Empirical Study on Chemotherapeutic Susceptibility of SP Cells in Human Pulmonary Adenocarcinoma Cell Line A549 in Vitro

OBJECTIVE To explore the chemotherapeutic susceptibility of SP cells in human pulmonary adenocarcinoma cell line A549 and the possible mechanism of multidrug resistance.METHODS SP and non-SP （NSP） cells in the cell line A549 were isolated by fluorescence activated cell sorter. The susceptibility of SP and NSP cells to DDP, 5-FU, VP16, NVB and GEM was detected by a drug susceptibility test, and IC50s were calculated 24 h a er the chemotherapy; and then a er a 2-hour IC50 treatment with 5 chemotherapeutic drugs on the 2 subsets of NSP cells, the intracellular drug levels were determined and analyzed using high performance liquid chromatograph.RESULTS There was no statistical signifi cance in comparison of the di. erences in IC50s and in intracellular drug levels a er DDP treatment between the 2 subsets （P 〉 0.05）, （P 〉 0.05）. However,all IC50s of the other 4 drugs were significantly higher in the SP cells than in the NSP cells （P 〈 0.01）. A er the chemotherapy, the intracellular drug levels of the other 4 drugs were significantly lower in SP cells than in NSP cells （P 〈 0.01）.CONCLUSION Compared to NSP cells, SP cells in the cell line A549 have stronger resistance to the chemotherapeutics. The multidrug resistance of SP cells closely correlates with the function of SP cells discharging chemotherapeutic agents.

Clinical Utility of Tumor Markers

Tumor markers comprise a wide spectrum of biomacromolecules excessively synthesized by a variety of neoplastic cells. These markers can be endogenous products of highly active metabolites from malignant neoplastic cells or the products of newly activated genes. Ideally, tumor markers should be highly sensitive, specific, and reliable with a high prognostic value and organ specificity. In addition, they should reflect the tumor stage. However, no tumor markers identified thus far have all of these characteristics. Nevertheless, most tumor markers show excellent clinical relevance for monitoring the efficacy of a variety of therapies. We herein review how to use the recommended tumor markers to diagnose malignancies, such as gastrointestinal carcinoma, liver cancer, bile duct/pancreatic cancer, lung cancer, breast cancer, gynecologic cancer, and urologic cancer.

THE EFFECTS OF HSP27 ON THE CYTOTOXICITY OF RAT EMBRYO FIBROBLAST INDUCED BY CISPLATIN

Objective: To investigate the protective effects of heat shock protein 2700(Hsp27) on cisplatin inducing cytotoxicity in a temperature mutant SV40 large T antigen transformed rat embryo fibroblast (P1-Hsp27). Methods The cytotoxical effects of cisplatin on the proliferation status of P1-Hsp27 cells in the presence or absence of Hsp27 were measured by MTT assay. Results Cisplatin possessed dose-dependent cytotoxicity on P1-Hsp27 cells. 48h after treatment, about 50% cells were dead in those cells exposed to 200μmol cislatin. However, no obvious protective effects of Hsp27 on cisplatin induced cytotoxicity could he observed (P>0. 05), except in those cells exposed to 500μmol cisplatin 12h after treatment.Conclusion Hsp27 has no obvious protective effects on cisplatin inducing cytotoxicity.

Liver cell adenoma with malignant transformation:A case report

A 57-year-old woman was referred to our hospital because of a liver mass detected by computed tomography.She had taken oral contraceptives for only one month at the age of thirty.Physical examination revealed no abnormalities,and laboratory data,including hepatic function tests,were within the normal range,with the exception of elevated levels of those serum proteins induced by the absence of vitamin K or by raised levels of the antagonist (PIVKA)-Ⅱ (3 502 AU/ml). Abdominal ultrasonography revealed a hyperechoic mass measuring 10×10 cm in the left posterior segment of the liver.Because hepatocellular carcinoma could not be completely excluded,this mass was resected.The tumor consisted of sheets of uniform cells with clear cytoplasm, perinuclear eosinophilic granules and round nuclei.These histological findings were consistent with liver cell adenoma. Background hepatic tissue appeared normal.After resection of the tumor,serum PIVKA-Ⅱ fell to within the normal range. An area of hepatocellular carcinoma (HCC) with a mid- trabecular pattern was immunohistochemically found,which was positive for PIVKA-Ⅱ.Sinusoidal endothelial cells were CD34-positive,containing scattered PIVKA-Ⅱ positive cells. This tumor was therefore finally diagnosed as liver cell adenoma with focal malignant transformation to HCC.

Telomere and telomerase in the initial stage of immortalization of esophageal epithelial cell

AIM: To search for the biomarker of cellular immortalization, the telomere length, telomerase activity and its subunits in cultured epithelial cells of human fetal esophagus in the process of immortalization. METHODS: The transgenic cell line of human fetal esophageal epithelium (SHEE) was established with E(6)E(7) genes of human papillomavirus (HPV) type 18 in our laboratory. Morphological phenotype of cultured SHEE cells from the 6th to 30th passages, was examined by phase contrast microscopy, the telomere length was assayed by Southern blot method, and the activity of telomerase was analyzed by telomeric repeat amplification protocol (TRAP). Expressions of subunits of telomerase, hTR and hTERT, were assessed by RT-PCR. DNA content in cell cycle was detected by flow cytometry. The cell apoptosis was examined by electron microscopy (EM) and TUNEL label. RESULTS: SHEE cells from the 6th to 10th passages showed cellular proliferation with a good differentiation. From the 12th to the 16th passages, many senescent and apoptotic cells appeared, and the telomere length sharply shortened from 23kb to 17kb without expression of hTERT and telomerase activity. At the 20th passage, SHEE cells overcame the senescence and apoptosis and restored their proliferative activity with expression of telomerase and hTERT at low levels, but the telomere length shortened continuously to the lowest of 3kb. After the 30th passage cells proliferation was restored by increment of cells at S and G2M phase in the cell cycle and telomerase activity expressed at high levels and with maintenance of telomere length. CONCLUSION: At the early stage of SHEE cells, telomeres are shortened without expression of telomerase and hTERT causing cellular senescence and cell death. From the 20th to the 30th passages, the activation of telomerase and maintenance of telomere length show a progressive process for immortalization of esophageal epithelial cells. The expression of telomerase may constitute a biomarker for detection of immortalization of cells.

Carcinogenic potential of duodenal reflux juice from patients with long-standing postgastrectomy

AIM: To determine whether study on the carcinogenic potential of reflux juice from patients with remote gastrectomy could clarify the inherent relationship between duodenal reflux and gastric stump cancer. METHODS: A total of 37 reflux juice samples (13 Billroth I, 24 Billroth II) were employed in the present study. A two-stage transformation assay using BALB/c 3T3 cells was carried out to test the initiating or promoting activity of these samples. RESULTS: Two of 18 (11.1%) reflux samples exerted initiating activities, whereas 9/19 (47.4%) samples enhanced the MNNG-initiating cell transformation, suggesting the duodenal reflux juice might more frequently possess the tumor-promoter activity (P = 0.029). In addition, there was no difference in initiating activities of the samples irrespective of surgical procedures (P = 0.488), while Billroth II samples exhibited stronger tumor-promoter activity than Billroth I samples (P = 0.027). Furthermore, the promoter activities were well correlated with the histological changes of the stomas (r(s) = 0.625, P = 0.004), but neither their cytotoxicities nor initiating activities had this correlation (Probabilities were 0.523 and 0.085, respectively). CONCLUSION: The duodenal reflux juice from patients with remote postgastrectomy did have carcinogenic potential, and suggested that tumor-promoting activity should principally account for the high incidence of gastric cancer in gastrectomy patients. In contrast, it is difficult to explain the high stump-cancer incidence with the N-nitroso compounds theory-a popular theory for the intact stomach carcinogenesis, and it seemed to be justified to focus chemo-prevention of this cancer on the tumor-promoting potential of reflux juice.

Effects of histone acetylation and DNA methylation on p21^(WAF1)regulation

Cell cycle progression is regulated by interactions between cyclins and cyclin-dependent kinases (CDKs). p21(WAF1) is one of the CIP/KIP family which inhibits CDKs activity. Increased expression of p21(WAF1) may play an important role in the growth arrest induced in transformed cells. Although the stability of the p21( WAF1) mRNA could be altered by different signals, cell differentiation and numerous influencing factors. However, recent studies suggest that two known mechanisms of epigenesis, i.e.gene inactivation by methylation in promoter region and changes to an inactive chromatin by histone deacetylation, seem to be the best candidate mechanisms for inactivation of p21( WAF1). To date, almost no coding region p21(WAF1) mutations have been found in tumor cells, despite extensive screening of hundreds of various tumors. Hypermethylation of the p21(WAF1) promoter region may represent an alternative mechanism by which the p21(WAF1/CIP1) gene can be inactivated. The reduction of cellular DNMT protein levels also induces a corresponding rapid increase in the cell cycle regulator p21(WAF1) protein demonstrating a regulatory link between DNMT and p21(WAF1) which is independent of methylation of DNA. Both histone hyperacetylation and hypoacetylation appear to be important in the carcinoma process, and induction of the p21(WAF1) gene by histone hyperacetylation may be a mechanism by which dietary fiber prevents carcinogenesis. Here, we review the influence of histone acetylation and DNA methylation on p21(WAF1) transcription, and affection of pathways or factors associated such as p 53, E2A, Sp1 as well as several histone deacetylation inhibitors.

Advances in the Researches on the Blocking Effect of Chinese Drugs on Tumors

Malignant tumors are caused by multiple carcinogenic factors undergoing several stages. The occurrence and development of tumors may be prevented and blocked if some effective interference factors are brought into play.1 At present, there are two main subjects for the researches, that is, blocking the precancerous lesions and blocking the develop-ment of tumors. The former focuses on the removing of carcinogenic factors and on the chemoprophylaxis of cancer, while the latter on the inhibition of cancer cell infiltration and cancerometastasis. These are summarized as follows.

Glioblastoma stem cells resistant to temozolomide-induced autophagy

Background Recent studies have demonstrated the existence of a small fraction of cells with features of primitive neural progenitor cells and tumor-initiating function in brain tumors. These cells might represent primary therapeutic target for complete eradication of the tumors. This study aimed to determine the resistant phenotype of glioblastoma stem cells （GSCs） to temozolomide （TMZ） and to explore the possible molecular mechanisms underlying TMZ resistance. Methods Freshly resected glioblastoma specimen was collected and magnetic isolation of GSCs was carried out using the Miltenyi Biotec CD133 Cell Isolation kit. The cytotoxic effect of TMZ on CD133^＋ and CD133^- glioblastoma cells was determined by using the 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay. Autophagy-related proteins （Beclin-1, LC3 and Atg5） and cleaved caspase-3 （p17） were analyzed by Western blotting. Immunofluorescent staining was used to detect Atg5, glial fibrillary acidic protein （GFAP） and CD133 expression in glioblastoma cells. Statistical analysis was carried out using SPSS 10.0 software. For all tests, the level of statistical significance was set at P 〈0.05. Results CD133^＋ glioblastoma ceils exhibited neurosphere-like growth in vitro and high expression of CD133 stem cell marker. The growth-inhibiting rate in CD133- glioblastoma cells treated with 5 or 50 pmol/L TMZ was significantly higher than that in CD133^＋ glioblastoma cells （（14.36±3.75）% vs （2.54±1.36）% or （25.95±5.25）% vs （2.72±1.84）%, respectively, P 〈0.05）. Atg5, LC3-11 and Beclin-1 levels were significantly lower in CD133^＋ glioblastoma cells than those in autologous CD133^- cells after TMZ treatment （P 〈0.05）. Caspase-3 was mildly activated only in CD133^- glioblastoma cells after exposure to TMZ （P 〈0.05）. Immunofluorescent staining revealed elevated expression of Atg5 in GFAP^＋ cells following TMZ treatment. Conclusions The GSCs display strong capability of tumor＇s resistance to TMZ. This resistance is probably contributed by the CD133^＋ cells with down-regulation of autophagy-related proteins. Future treatment should target this small population of cancer stem cells in tumors to improve survival of patients.

Breast cancer stem-like cells can promote metastasis by activating platelets and down-regulating antitumor activity of natural killer cells

OBJECTIVE:To investigate whether cancer stem cells(CSCs) more efficiently activating platelets and evading immune surveillance than non-CSCs thus promoting metastasis.METHODS:We enriched and identified sphereforming cells(SFCs) and coincubated washed platelets with several platelet activators including collagen,4T1 and SFCs.Platelet-coating tumor cells,platelet activation and TGF-β1 release were analyzed.Then natural kell cells(NK) were incubated with supernatants of different activated platelet samples what we called sample release(SR).The degranulation assay and NKG2 D expression on NK cells were conducted by flow cytometry.Finally tissue factor(TF) expression of SFCs or 4T1 were evaluated by western blot.RESULTS:Breast cancer cell line 4T1 could form spheres in serum-free medium at low adherence.Sphere-forming cells expressed high levels of the CD24-/lowCD44 + stem cell phenotype.Both sphere-forming cells or 4T1 were coated with abundant platelets while sphere-forming cells induced significantly higher expression of platelet activating receptor CD62 p than 4T1 did(P < 0.01).And sphere-forming cells induced platelets to produce more TGF-β1 than 4T1 did(P < 0.01).Furthermore,sample releases induced by sphere-forming cells caused more vigorous inhibition of NK cells antitumor reactivity(P < 0.05) and reduced NKG2 D expression(P < 0.01).The final results showed that sphere-forming cells expressed higher levels of TF than 4T1(P < 0.05).CONCLUSION:Our findings indicate that CSCs could efficiently activate platelets,induce platelets to secrete more TGF-β1,decrease NKG2 D expression and inhibit antitumor activity of NK cell,compared with 4T1.And higher levels of TF expression of CSCs may account for this correlation of CSCs and platelets.

Utility of cell-free nucleic acid and circulating tumor cell analyses in prostate cancer

Prostate cancer is characterized by bone metastases and difficulty of objectively measuring disease burden. In this context, cell-free circulating tumor DNA （ctDNA） and circulating tumor cell （CTC） quantitation and genomic profiling afford the ability to noninvasively and serially monitor the tumor. Recent data suggest that ctDNA and CTC quantitation are prognostic for survival. Indeed, CTC enumeration using the CellSearch~ platform is validated as a prognostic factor and warrants consideration as a stratification factor in randomized trials. Changes in quantities of CTCs using CellSearch also are prognostic and may be employed to detect a signal of activity of new agents. Molecular profiling of both CTCs and ctDNA for androgen receptor （AR） variants has been associated with outcomes in the setting of novel androgen inhibitors. Serial profiling to detect the evolution of new alterations may inform drug development and help develop precision medicine. The costs of these assays and the small quantities in which they are detectable in blood are a limitation, and novel platforms are required to address this challenge. The presence of multiple platforms to assay CTCs and ctDNA also warrants the consideration of a mechanism to allow comparison of data across platforms. Further validation and the continued development and standardization of these promising modalities will facilitate their adoption in the clinic.

Recent advances of miRNAs in the development and clinical application of gastric cancer

Gastric cancer(GC)is one of the most common malignant tumors.The mechanism of how GC develops is vague,and therapies are inefficient.The function of microRNAs(miRNAs)in tumorigenesis has attracted the attention from many scientists.During the development of GC,miRNAs function in the regulation of different phenotypes,such as proliferation,apoptosis,invasion and metastasis,drug sensitivity and resistance,and stem-cell-like properties.MiRNAs were evaluated for use in diagnostic and prognostic predictions and exhibited considerable accuracy.Although many problems exist for the application of therapy,current studies showed the antitumor effects of miRNAs.This paper reviews recent advances in miRNA mechanisms in the development of GC and the potential use of miRNAs in the diagnosis and treatment of GC.