Establishment and characterization of TSGH9201, a human gastric carcinoma cell line that is growth inhibited by epidermal growth factor

Conventional cytogenetic characterization of a new cell line, ACP01, established from a primary human gastric tumor

Gastric cancer is the second most frequent type of neoplasia and also the second most important cause of death in the world. Virtually all the established cell lines of gastric neoplasia were developed in Asian countries, and western countries have contributed very little to this area. In the present study we describe the establishment of the cell line ACP01 and characterize it cytogenetically by means of in vitro immortalization. Cells were transformed from an intestinal-type gastric adenocarcinoma (T4N2M0) originating from a 48-year-old male patient. This is the first gastric adenocarcinoma cell line established in Brazil. The most powerful application of the cell line ACP01 is in the assessment of cytotoxicity. Solid tumor cell lines from different origins have been treated with several conventional and investigational anticancer drugs. The ACP01 cell line is triploid, grows as a single, non-organized layer, similar to fibroblasts, with focus formation, heterogeneous division, and a cell cycle of approximately 40 h. Chromosome 8 trisomy, present in 60% of the cells, was the most frequent cytogenetic alteration. These data lead us to propose a multifactorial triggering of gastric cancer which evolves over multiple stages involving progressive genetic changes and clonal expansion.

Antagonistic activity against Helicobacter pylori infection in vitro by a strain of Enterococcus faecium TM39

Lactic acid bacteria (LAB) strains from infant feces were screened for anti-Helicobacter pylori use. In the beginning, we selected the strains based on their capability to adhere to the human intestinal epithelial cell (Int-407), colonial enterocyte-like Caco-2 cell, human cervical epithelioid carcinoma cell (HeLa), and human gastric carcinoma cell (TSGH 9201). Then, acid and bile salt tolerance of these LAB strains was evaluated. In addition, the ability of these LAB strains to inhibit the growth of H. pylori and to expel H. pylori cells from TSGH 9201 were studied. The spent culture supernatant (SCS) of a selected strain TM39, i.e., TM39-SCS, significantly inhibited the viability of H. pylori in vitro. It also inhibited the urease activity of H. pylori in vitro. For these antagonistic effects, in addition to pH and lactic acid, some factors in TM39-SCS might play the major role. Treatment of H. pylori with the SCS or cells of strain TM39 significant reduced its binding to TSGH 9201 cells. Although strain TM39 is identified as Enterococcus faecium, it is not vancomycin resistant and is proved to be safe through the invasion study and a 28-day feeding study with Wistar rats.

Direct growth suppressive activity of interferon-alpha and -gamma on human gastric cancer cells

BACKGROUND AND OBJECTIVES

Interferons (IFNs) exhibit anti-tumor activities through either immune modulation or direct anti-tumor effects. We have investigated the activity and mechanisms of IFN-alpha and IFN-gamma on the growth of TSGH9201, TMK-1 and AGS gastric cancer cells in vitro.

METHODS

Activities of IFNs on cell growth were analyzed by measuring total cellular DNA. Effects of IFNs on apoptosis was evaluated by formation of in situ DNA breakage and DNA ladders. Effects of IFNs on cells cycle phase distribution were analyzed using flow cytometry. Levels of Bcl-2 family proteins after treatment with IFNs were analyzed using Western blot.

RESULTS

Both IFN-alpha and IFN-gamma were active in suppressing the growth of TSGH9201 and TMK-1 cells, while AGS cells were resistant to treatment with IFNs. The IC(50)s of IFN-alpha for TSGH9201 and TMK-1 cells were 300 and 500 U/ml, respectively, and the IC(50)s of IFN-gamma were 40 and 2.0 U/ml, respectively. Both IFN-alpha- and IFN-gamma-induced cell cycle arrest in sensitive cells. IFN-gamma also increased cellular apoptosis, demonstrated by increasing in situ DNA damage and DNA fragmentation. IFN-gamma increased BAK protein levels and decreased Bcl-2 and Bcl-X(S) protein levels in TSGH9201 cells.

CONCLUSIONS

IFN-alpha suppressed growth of gastric cancer cells through induction of cell cycle arrest. IFN-gamma suppressed cell growth through induction of both cell cycle arrest and apoptosis. IFN-gamma-mediated apoptosis was associated with the alteration in protein levels of Bcl-2, Bcl-X(S) and BAK.

A novel podophyllotoxin-derived compound GL331 is more potent than its congener VP-16 in killing refractory cancer cells

PURPOSE

GL331 is a new homolog of VP-16, and has demonstrated more efficacious anti-cancer activity in both the in vitro and in vivo lymphoma systems. To extensively explore GL331's clinical value, we furthermore evaluate the cytotoxicity and apoptosis-inducing activity of GL331 in several human cell lines from cancers that are not normally treated with VP-16.

METHODS

By MTT and clonogenic survival assays, the cytotoxicities of GL331 and VP-16 were evaluated in a variety of cell lines including nasopharyngeal, hepatocellular, gastric, colon, cervical, and neuroblastoma cancer types. Western blot analysis was performed to detect the MDR-1 level in these cell lines. By Annexin V-staining flow cytometry and detection of DNA ladders, the apoptosis-inducing activities of GL331 and VP-16 were also evaluated.

RESULTS

GL331 showed more efficacy than its congener VP-16 in killing cancer cells. The estimated ID50 of GL331 were 2.5 to 17-fold lowerthan those of VP-16. GL331 possessed more cell-killing activity even in MDR-1-overexpressing cell lines such as HCC36 and SW620. Its higher cytotoxicity could be attributed by the elevated ability to induce apoptotic cell death.

CONCLUSION

GL331's overriding drug resistance and higher cancer cell-killing activity suggest its superiority in clinical cancer therapy.

Establishment and characterization of two cell lines derived from human diffuse gastric carcinomas xenografted in nude mice

Two human diffuse gastric carcinoma cell lines were established in vitro from xenografted tumours serially passaged in nude mice. Of 12 primary diffuse gastric carcinomas, 7 were successfully xenografted in nude mice (58.3%). Short-term primary cultures were achieved in all the xenografted lines. However, only 2 of the 7 short-term primary cultures were established as long-term cultures (GP202 and GP220). GP202 cells are larger than GP220 cells, show less abundant intercellular junctions at the ultrastructural level and grow in culture as a compact thin monolayer. The GP220 cells grow preferentially in small clusters attached to the monolayer, with a subpopulation of floating cells. Both lines have cells containing small mucin vacuoles in the cytoplasm and cells displaying a typical signet-ring shape. GP202 cells grow as solid tumours in nude mice but GP220 cells do not give rise to tumours. The flow cytometry and karyotype analysis showed aneuploidy in GP202 cells, with many numerical and structural chromosomal abnormalities, and diploidy in GP220 cells, with several structural chromosomal abnormalities. The CDw75 and Tn antigens are more prominently expressed in GP202 cells than in GP220 cells. T antigen is only expressed in GP202 cells, whereas only GP220 cells express EGFR. Sialosyl-Tn is not expressed in either of the cell lines. The gastric cancer cell lines described in this paper represent a valuable addition to the small number of diffuse gastric cancer cell lines currently available and also provide a good model for further in vitro and in vivo studies of gastric carcinogenesis.