Further Report on Carcinogenesis or Tumorigenicity ofMDCK Canine Kidney Cell(CKC) Lines and Analysis ofTheir Chromosome Karyotypes

Using Hela cell cultures as positive control and primary canine kidney cell (CKC) or feline kidney cell (FKC) cultures purified in vitro on passage 3 as negative control, the tumorigenicity of Madin-Darby canine kidney (MDCK) cells was tested in >273 nude mice, and colony formation in soft agarose and haemag-glutination under different concentration of plant lectins of these cells were carried out at the same time. Subsequently, very low tumorigenicity strains of MDCK line were successfully selected; these were evaluated for the production of canine or feline combination viral vaccines, free of infectious agents, and of known cytoge-netic and tumorigenic. It is thus evident that MDCK cell of M, JB, JC, WB or H strain can be approved as substrate for the preparation of attenuated viral vaccines, but MDCK cell of YA, YB and KA strains can not be approved as substrate for the preparation of attenuated viral vaccines. The heritable character of these cell sub-lines is comparatively stable, and shows little significant difference between passages.

Experimental Researches on Carcinogenesis or Tumorigenicity of MDCK Canine Kidney Cell(CKC) Lines and Analysis of Their Chromosome Karyotypes

The chromosomal number variations & structural aberrations of the MDCK cell line, primary feline or canine kidney cell(FKC or CKC) and Hela cell line were investigated and their karyotypes of conventional chromosome bands were analyzed. The carcinogenesis or tumorigenicity testing of these cell lines in about 232 nude mice and for colony formation in soft agarose and for haemagglutination under different concentration of plant lectins of these cells were carried out. Under the prerequisite that the incidence of cancer or tumor in negative-control nude mice inoculated subcutaneously with primary feline or canine kidney cell cultures purified in vitro at passage 3 was 0 (0/22) and 0 (0/10), respectively. The incidence of the progressively-growing malignant tumor(MT) in positive-control nude mice inoculated subcutaneously with Hela cell cultures of KB, X, or NM20/X strain was 10/10, 25/25 and 5/51, respectively. The results showed that the incidence of tumor in nude mice with tetraploid YA strain of MDCK cell during 20 - 45 passages, with hy-podiploid JB strain of MDCK cell on passage 25, with di-and hypoploid JC strain of MDCK cell during 2-15 passages or with hypoploid M strain of MDCK cell during 9 - 27 passages was 28/58, 1/5, 4/18 and 0/31, respectively. The chromosomal analysis results showed that the ratio of difference in the rate of modal chromosome number between high(mcs+ n) and lowest (mcs) passages was not more than 5% - 15% and the structure aberrations was generally 0 - 3% . These results proved that the genetic characteristics of chromosomal number of cell lines determines their tumorigenicity, but it is species-specific. MDCK line has tumorigenicity no matter what its chromosome karyotype is, at least it has very low tumorigenicity even when its modal chromosome number is hypoploid. The repeatedly frozen, thawed and split controls of tumorigenicity-positive cell lines(X strain of Hela, M strain of BHK-21, JA strain of Vero, YA strain of MDCK) have much lower tumorigenicity or are even non-carcinogenesis, and the repeatedly frozen, thawed and split controls of very low tumorigenicity cell lines (M or JC strain of MDCK) are certainly non-carcinogenic and never have increased tumorigenicity. It is thus evident that MDCK cell of M, JB or JC strain can be approved as substrate for the preparation of attenuated viral vaccines, but MDCK cell of YA strain can not be approved as substrate for the preparation of attenuated viral vaccines. In summary, all strains of MDCK cell line have tunorigenicity, at least have low tumor igencity , never have non-cancinogenic MDCK, but very low tumorigenicity MDCK cell strains can certainly be used for the approval production of canine viral vaccines if the DNA content in viral cell cultures was remarkably decreased through conventional means in manufacturing process. Therefore, the master cell stock and working cell bank of MDCK line used for vaccine manufacture were established in China, which are free of infectious agents, and described with respect to cytogenetic characteristics and tumorigenicity.Tests showed that there were correlations among cell line chromosome number variations, anchorage independence in soft a-garose, haemagglutination under plant lectins, and tumor-forming ability in nude mice, thus all the in vitro tests are economic, simple and reliable means for monitoring the tumor-forming ability of MDCK line in nude mice.

Establishment and characterization of a new cell line derived from half-smooth tongue sole Cynoglossus semilaevis kidney

In this study,we established a new cell line(Cynoglossus semilaevis kidney cells,CSK)from kidney of the half-smooth tongue sole(Cynoglossus semilaevis).The cells were subcultured over 1000 days and passaged for more than 100 times.Additionally,CSK cells were optimally maintained in Dulbecco's modified Eagle medium nutrient mixture F-12 supplemented with HEPES,antibiotics,fetal bovine serum,2-mercaptoethanol,and basic fibroblast growth factor.The optimum growth temperature for CSK cells was 25℃,and the cells showed a fibroblast-like phenotype.Chromosome analysis revealed that CSK cells had a normal diploid karyotype with 2 n=42.CSK cells were susceptible to Grouper nervous necrosis virus(NNV),and cytopathic ef fects were observed at 3–5 days postinfection.The NNV sensitivity of CSK cells was related to the high abundance of virions in the cytoplasm,as observed by electron microscopy.Additionally,CSK cells could be successfully transfected with a green fluorescent protein reporter plasmid,and fluorescent signals were easily observed.Finally,immunocytochemistry analysis showed that CSK cells were supporting cells.Overall,we established this new cell line,which may have potential applications in the identification of viral pathogens af fecting the half-smooth tongue sole.

Translating new data to the daily practice in second line treatment of renal cell carcinoma:The role of tumor growth rate

The therapeutic options for patients with metastatic renal cell carcinoma(mRCC) have completely changed during the last ten years. With the sequential use of targeted therapies, median overall survival has increased in daily practice and now it is not uncommon to see patients surviving kidney cancer for more than four to five years. Once treatment fails with the first line targeted therapy, head to head comparisons have shown that cabozantinib, nivolumab and the combination of lenvatinib plus everolimus are more effective than everolimus alone and that axitinib is more active than sorafenib. Unfortunately, it is very unlikely that we will ever have prospective data comparing the activity of axitinib, cabozantinib, lenvatinib or nivolumab. It is frustrating to observe the lack of biomarkers that we have in this field, thus there is no firm recommendation about the optimal sequence of treatment in the second line. In the absence of reliable biomarkers, there are several clinical endpoints that can help physicians to make decisions for an individual patient, such as the tumor burden, the expected response rate and the time to achieve the response to each agent, the prior response to the agent administered, the toxicity profile of the different compounds and patient preference. Here, we propose the introduction of the tumor-growth rate(TGR) during first-line treatment as a new tool to be used to select the second line strategy in m RCC. The rapidness of TGR before the onset of the treatment reflects the variability between patients in terms of tumor growth kinetics and it could be a surrogate marker of tumor aggressiveness that may guide treatment decisions.

Tumor cell death visualization of renal cell carcinoma under the combined effect of the Gratiola officinalis extract and cyclophosphamide using fluorescent staining methods

Objective of the study:We used fluorescence imaging methods of apoptosis and necrosis in human renal carcinoma A498 tumor cells in vitro to reveal the indicated forms of cell death under the combined effect of flavonoid-containing extract of Gratiola officinalis and cytostatic(cyclo-phosphamide).Materials and methods:The dyes were propidium iodide and acridine orange,which were used in the"alive and dead"test.This test helped us to identify the total number of dead cells in the forms of necrosis and apoptosis and the number of cells in which apoptosis had started,it was characterized by the appearance of apoptotic bodies or nucleus pyknosis.Results:We found the most pronounced cytotoxic activity at the ratio of extract of Gratiola officinalis and cyclophosphamide concentrations of 1∶1.The number of living cells decreased when exposed to the ratio of extract and cytostatic concentrations of 2∶1.When the ratio of concentration of the extract relative to the cytostatic increased to 3∶1,the cytostatic activity of the extract began to appear,the total number of tumor cells decreased.The number of cells with nucleus pyknosis and the number of cells with apoptosis signs significantly increased at a 3∶1 ratio of extract and cytostatic concentrations,which confirms the presence of pro-apoptotic activity of the studied combination.This trend indicates the dependence of a certain form of cell death(apoptosis,necrosis)on the ratio of extract and cytostatic doses,and it also demon-strates the cytostatic and cytotoxic effects of this combination.Conclusion:Fluorescence methods of investigation in the"alive and dead"test allowed us to visualize the forms of cell death of human kidney carcinoma A498 by combined exposure to the fiavonoid-containing extract of Gratiola officinalis and cytostatic(cyclophosphamide)24 h after exposure.We found that the combination with a concentration ratio of the extract and cyclophosphamide of 3:1 has the greatest effectiveness due to stimulation of the cytostatic effect and cytotoxic effect.