Displayed correlation between gene expression profiles and submicroscopic alterations in response to cetuximab, gefitinib and EGF in human colon cancer cell lines

Abstract

BackgroundEGFR is frequently overexpressed in colon cancer. We characterized HT-29 and Caco-2, human colon cancer cell lines, untreated and treated with cetuximab or gefitinib alone and in combination with EGF.MethodsCell growth was determined using a variation on the MTT assay. Cell-cycle analysis was conducted by flow cytometry. Immunohistochemistry was performed to evaluate EGFR expression and scanning electron microscopy (SEM) evidenced the ultrastructural morphology. Gene expression profiling was performed using hybridization of the microarray Ocimum Pan Human 40 K array A.ResultsCaco-2 and HT-29 were respectively 66.25 and 59.24 % in G0/G1. They maintained this level of cell cycle distribution after treatment, suggesting a predominantly differentiated state. Treatment of Caco-2 with EGF or the two EGFR inhibitors produced a significant reduction in their viability. SEM clearly showed morphological cellular transformations in the direction of cellular death in both cell lines treated with EGFR inhibitors. HT-29 and Caco-2 displayed an important reduction of the microvilli (which also lose their erect position in Caco-2), possibly invalidating microvilli absorption function. HT-29 treated with cetuximab lost their boundary contacts and showed filipodi; when treated with gefitinib, they showed some vesicles: generally membrane reshaping is evident. Both cell lines showed a similar behavior in terms of on/off switched genes upon treatment with cetuximab. The gefitinib global gene expression pattern was different for the 2 cell lines; gefitinib treatment induced more changes, but directly correlated with EGF treatment.In cetuximab or gefitinib plus EGF treatments there was possible summation of the morphological effects: cells seemed more weakly affected by the transformation towards apoptosis. The genes appeared to be less stimulated than for single drug cases.ConclusionThis is the first study to have systematically investigated the effect of cetuximab or gefitinib, alone and in combination with EGF, on human colon cancer cell lines. The EGFR inhibitors have a weaker effect in the presence of EGF that binds EGFR. Cetuximab treatment showed an expression pattern that inversely correlates with EGF treatment. We found interesting cyto-morphological features closely relating to gene expression profile. Both drugs have an effect on differentiation towards cellular death.

Treatment with cucurbitacin B alone and in combination with gefitinib induces cell cycle inhibition and apoptosis via EGFR and JAK/STAT pathway in human colorectal cancer cell lines

“…49 Moreover, Solmi et al also found that treatment with Gef showed a significant reduction in cell viability on Caco-2 and HT-29 colon cancer cells in a dose-and time-dependent manner. 50 According to these findings, our results were also supported by the fact that Gef treatment decreased cell viability in a time-and dose-dependent manner in both HCT-116 and HT-29 cells with IC 50 values 50 mM (24 h).…”

“…As shown in Figure 1 To examine the antiproliferative effect of CuB when combined with Gef, we have chosen one randomized concentration, which was 10 mM, that had been below the IC 50 …”

Indomethacin and juglone inhibit inflammatory molecules to induce apoptosis in colon cancer cells

“…After fixing, the cells were stained with propidium iodide (0.05 mg/mL), as described earlier [28] and analyzed using a FACSCalibur flow cytometer (Becton Dickinson). After fixing, the cells were stained with propidium iodide (0.05 mg/mL), as described earlier [28] and analyzed using a FACSCalibur flow cytometer (Becton Dickinson).…”

Recycling antimalarial leads for cancer: Antiproliferative properties of N-cinnamoyl chloroquine analogues

“…HER-2 is over-expressed in all three cancer cell lines used in the present study. [17][18][19] According to the literature, HKI-272 most likely acts by irreversibly binding to a cysteine in the ATP-binding pocket of HER-2, 20 a behavior that might also be displayed by our compounds, as their Michael acceptor moiety could engage in the S-alkylation of the critical Cys residue in HER-2. Still, this is a highly hypothetical example of what could be the MOA for our compounds, amongst the wide range of inhibition processes in which both the quinoline and the Michael acceptor moieties could participate, leading to impairment of tumor cell growth.…”