Proliferation Of CaSki Cells Research Articles

Effect of hyperthermia on the apoptosis and proliferation of CaSki cells

Hyperthermia is a promising treatment for human cervical cancer. However, little is known about whether and under what conditions heat treatment exerts tumor inhibition effects on cervical cancer, and the molecular mechanisms behind these cellular responses have yet to be elucidated. We employed the human cervical cancer cell line CaSki as a cellular model and examined the effect of cell apoptosis and proliferation under gradient thermal conditions (43, 45 and 47˚C for 40 min). Heat treatment was found to induce CaSki cell apoptosis and necrosis. Cell cycle analysis showed that cells were arrested in S phase upon the application of hyperthermia, and MTT analysis revealed that cell viability was also reduced. Of the thermal conditions, 45˚C exhibited the best induction of apoptosis, while 47˚C induced direct fierce necrosis. This was further demonstrated by examining the expression level of several key apoptosis-related genes: caspase-3, Smac and Survivin. During apoptosis, caspase-3 and Smac levels were up-regulated, whereas anti-apoptotic Survivin was down-regulated, enhancing programmed cell death. Our results reveal that heating at ≥45˚C induced cell apoptosis and necrosis, and inhibited cell proliferation at both the cellular and molecular levels. These findings support the use of hyperthermia in a clinical setting for the treatment of human cervical cancer.

Inhibition of ADP-ribosylation factor-like 6 interacting protein 1 suppresses proliferation and reduces tumor cell invasion in CaSki human cervical cancer cells

ADP-ribosylation factor-like 6 interacting protein 1 (ARL6IP1) is an apoptotic regulator. To investigate the role of ARL6IP1 in human cervical cancer progression, we designed and used short hairpin RNA (shRNA) to inhibit ARL6IP1 expression in CaSki cells and validated its effect on cell proliferation and invasion. Changes in gene expression were analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) or western blot. Down-regulation of ARL6IP1 expression by infection with ARL6IP1-specific RNAi-expressing vector inhibited CaSki cell proliferation and colony formation. In addition, down-regulation of ARL6IP1 expression arrested CaSki cell cycling at the G0/G1 phase and mitigated CaSki cell migration, determined by wound healing assays. ARL6IP1 was involved in cervical cancer cell growth, cell cycle progression, and invasion through regulation of gene expression, such as Caspase-3, Caspase-9, p53, TAp63, NF-κB, MAPK, Bcl-2, and Bcl-xL, suggesting that ARL6IP1 could have important implications in cervical cancer biology. Our findings illustrate the biological significance of ARL6IP1 in cervical cancer progression, and provide novel evidence that ARL6IP1 may serve as a therapeutic target in the prevention of human cervical cancer.

Effects of curcumin on invasion and metastasis in the human cervical cancer cells Caski

To explore the effects of curcumin on invasion and metastasis in the human cervical cancer cells Caski. Caski cells were treated with 10, 25, 50μmol/L curcumin for 24, 48, 72 h. Proliferation of Caski cells was measured with MTT assay. When treated with 50μmol/L curcumin for 72 h, the expressions of MMP-2, MT1-MMP and NF-κB of cells were detected by Western-blot, and invasion and metastasis of Caski cells were evaluated with transwell chamber. After being treated with 10μmol/L, 25μmol/L, 50μmol/L curcumin for 24, 48 and 72 h, the proliferation of Caski cells was inhibited in a dose-and time-dependent manner. The expression of MMP-2, MT1-MMP and NF-κB were decreased when being treated with 50μmol/L curcumin for 72 h. After treatment with 50μmol/L curcumin, in invasion assay, the number of cells in curcumin treated group to migrate to filter coated with Matrigel was reduced compared with control group(P<0.05). Meanwhile, in migration assay, the number of cells in curcumin treated group to migrate to filter was also decreased compared with control group (P<0.05). Curcumin could affect the invasion and metastasis of the human cervical cancer cells Caski. Inhibiting the expression of MMP-2, MT1-MMP and NF-κB was probably one of its molecular mechanisms.

AICAR inhibits proliferation and induced S-phase arrest, and promotes apoptosis in CaSki cells

The aim of the present study was to determine the effect of 5-aminoimidazole-4-carboxamide-ribonucleoside (AICAR) on proliferation, cell cycle, and apoptosis in the human epithelial cervical cancer cell line CaSki cells. Cell count and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay were used to determine cell proliferation and viability. Hoechst 33258 staining was conducted to distinguish the apoptotic cells. Cell cycle and Annexin-V/propidium iodide staining were analyzed by fluorescence-activated cell sorting (FACS). A Western blot assay was used to evaluate the expression of AKT (also known as protein kinase B), mammalian target of rapamycin (mTOR), p53, and extracellular signal-regulated kinase (ERK). AICAR (500 micromol/L) significantly inhibited the proliferation of CaSki cells treated for 24, 48, and 72 h as determined by cell count. The cells at the G1 and G2 phases were dramatically decreased while cells at the S phase were increased in response to AICAR treatment for 24, 48, and 72 h. The MTT assay showed less viable cells and Hoechst fluorescent staining showed more apoptotic cells upon AICAR stimulation. The results of the Annexin-V staining demonstrated a time-dependent increase of apoptosis in cells treated with AICAR for 24, 36, and 48 h. Furthermore, AICAR activated caspase-3 in a time-dependent manner. It was also found that AICAR inhibited the phosphorylation of AKT and mTOR, which are important kinases regulating cell growth and survival. AICAR stimulation obviously increased the expression of the tumor suppressor p53 and the phosphorylation of ERK. AICAR inhibited proliferation and induced S phase arrest and promoted apoptosis in CaSki cells, which might be mediated by the downregulation of the AKT/mTOR pathway and the upregulation of the p53/ERK pathway.

Adenovirus-Mediated p53 Treatment Enhances Photodynamic Antitumor Response

Photodynamic therapy (PDT) has been reported to be effective for treating various tumors and to induce apoptosis in many tumor cells. In this study, we evaluated the ability of PDT combined with a tumor suppressor factor, recombinant adenovirus p53 (AdCMVp53), to induce apoptosis as well as cell growth inhibition in CaSki human cervical cancer cells and in nude mice with implanted CaSki cells. To examine levels of apoptosis, CaSki cells were treated with PDT and/or AdCMVp53, and an annexin V-staining assay was then conducted. In addition, Western blot analysis was done to identify p53 induction at the cellular and tumor tissue levels. PDT+AdCMVp53 cotreatment caused remarkable inhibition of CaSki cell proliferation, as compared with the individual treatments. In parallel with the inhibition of cell proliferation, the cotreatment caused a significantly greater increase in the annexin V-stained cell population compared with the individual treatments, as determined by fluorescence-activated cell-sorting analysis. The Western blotting assay also showed significantly more cellular p53 expressed after PDT+AdCMVp53 cotreatment than after each separate treatment. This was consistent with observations of tumor tissue in the mouse system. However, apoptosis- related protein, p21, was significantly suppressed by PDT+AdCMVp53 cotreatment, contrary to treatment with AdCMVp53 alone. Taken together, these findings suggest that PDT plus AdCMVp53 gene therapy exerts more potent antitumor effects on human cervical cancer cells, with induction of apoptosis at least through activation in p53 protein at the cellular and tumor tissue levels.

Mechanism of translation of the bicistronic mRNA encoding human papillomavirus type 16 E6-E7 genes

The transforming genes E6 and E7 of human papillomavirus (HPV) type 16 and other HPV types are expressed from a bicistronic mRNA with a characteristic spacing of 3 to 6 bp between the termination codon of E6 and the initiation codon of E7. Plasmid pSP64E6E7 which contains the reading frames of both E6 and E7 was constructed in order to study the expression of both proteins in a coupled transcription/rabbit reticulocyte translation system. Both E6 and E7 proteins were expressed simultaneously. This translation could be interfered with by antisense oligonucleotides corresponding to various regions of the transcript. Antisense oligonucleotides targeted at sequences flanking either side of the translation initiation codon of the E6 open reading frame were effective in inhibiting the synthesis of both proteins, whereas oligonucleotides complementary to the coding regions downstream of the first start codon showed either a considerably reduced effect or none at all. In particular, there was limited inhibition of E7 translation by antisense oligonucleotides flanking the translation start region of the E7 gene. In the presence of RNase H, it was possible to selectively inhibit the synthesis of either E6 or E7 by several gene-internal antisense oligonucleotides. We conclude that HPV16 E6-E7 bicistronic mRNA is fully functional and that both proteins are translated with equal efficiency via the scanning mechanisms with reinitiation at the second open reading frame. In addition, both AE6 and AE7 may have therapeutical potential as they are capable of inhibiting the proliferation of CaSki cells which contain the HPV16 genome.

Cationic liposomes mediated delivery of antisense oligonucleotides targeted to HPV 16 E7 mRNA in CaSki cells

The “high risk” types 16 and 18 of human papillomavirus (HPV) are involved in the etiology of genital squamous cell carcinoma. The early genes 6 and 7 (E6–E7) of these viruses code for the major transforming proteins, capable of inducing cell transformation alone or acting synergistically with other oncogenes. Antisense oligonucleotides, recently applied to inhibit the functions of a number of cellular and viral proteins, might provide the basis for a new therapeutic strategy against HPV-induced malignancies. We studied the proliferation of CaSki cells by the MTT assay after their exposure to HPV 16 E7 mRNA antisense oligonucleotides with and without cationic liposomes (containing dimethyldioctadecylammonium bromide DDAB, and dioleylphosphatidylethanolamine, DOPE). Unmodified oligonucleotides (either 12- or 23-mers) did not have nay effect on either CaSki cell proliferation or morphology when compared with the untreated cells. The cellular uptake of oligonucleotides was significantly enhanced by the cationic liposomes as assessed by confocal laser scanning microscopy (CLSM). The cationic liposomes were toxic to the cells as demonstrated by the reduced cell number and altered cell morphology. Only a slight reduction of the cell proliferation was seen when antisense 12-mer was protected from its 3′- and 5′-ends with thiolated and FITC, respectively. Both the 12- and the 23-mers with the cationic liposomes inhibited cell proliferation, the inhibitory effect being longer with the 23-mer. Overall, the MTT assay was less sensitive than light microscopy to reveal the toxic effects on CaSki cells. The results suggest that antisense oligonucleotides targeted to HPV 16 E7 mRNA can be introduced into CaSki cells with cationic liposomes.