ABSTRACT
Gsalpha gene mutation has been discovered in some human tumors. In our previous studies, three novel deletants of Gsalpha gene, Gsalpha L-1(500 bp), Gsalpha L-2(300 bp), and Gsalpha L-3(200 bp), and wild type Gsalpha-4(1 200 bp) were found in human leukemia cell lines and detected in leukemic cells from patients with acute leukemia. To investigate the construction, function and biological significance of the deletants, the plasmids of Gsalpha L-1, Gsalpha L-2 and wild Gsalpha-4 were transformed into E. coli DH5, amplified by PCR, and cloned in expression vector pET22b(+), and then transformed into E. coli, respectively. As a result, higher levels of expression of three recombinants were obtained in form of inclusion bodies. The results suggested that these Gsalpha isoforms have an open reading frame of gene and can be expressed in vitro. The data lay a foundation to study the relation of Gsalpha gene to leukemogenesis.
ABSTRACT
Objective: To select highly metastatic cells from human salivary gland mucoepidermoid carcinoma cell clone Mc3. Methods: In situ transplantation of Mc3 cells into submandibular gland of nude mice, in situ transplantation of Mc3 induced lung metastasized tumor tissue among nude mice and cell culture were employed to obtain the wanted cells. Morphological observation, cell growth analysis, flow cytometry, chromosome staining, clonogenic assay and artificial metastasis test in nude mice were used to characterize the cells. Results: Lung metastasis was observed in 3 out of 10 nude mice after 4 cycles of in situ transplantation of Mc3 cell induced lung metastasized tumor tissue. Epidermoid cells with similar morphology to Mc3 were obtained through cell culture and the cells were named M3SP4. M3SP4 cell induced lung metastatic foci were histologicaly proved to be mucoepidermoid carcinoma. Subdiploid karyotype with human chromosome morphology was observed in M3SP4 and Mc3 cells. The population doubling time (h) of M3SP4 and Mc3 cells was 23.9 and 25.9, the percentage of S phase cells in cell cycle 26.8 and 15.3, clonogenecity (%) 54.6 and 30.2, respectively. The artificial lung metastatic potential of M3SP4 cells was 35% higher than that of Mc3 in nude mice. Conclusion: M3SP4 cells are of human mucoepidermoid carcinoma with higher metastatic potential than Mc3. In situ transplantation of mucoepidermoid carcinoma cells or lung metastasized tumor tissue may maintain the metastatic potential of the cells.