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Dependence of Relative Expression of NTR1 and EGFR on Cell Density and Extracellular pH in Human Pancreatic Cancer Cell Lines.

Olszewski-Hamilton U, Hamilton G - Cancers (Basel) (2011)

Bottom Line: MTT assays revealed the NTR1 inhibitor SR 142948-sensitive Lys8-ψ-Lys9NT (8-13)-induced proliferation in BxPC-3 and PANC-1 cells.IL-8 production was stimulated by Lys8-ψ-Lys9NT (8-13) and even enhanced at both acidic and alkaline pHe in BxPC-3 and PANC-1 cells.In conclusion, our in vitro study suggests that one contributing factor to the minor responses obtained with EGFR-directed therapy may be downregulation of this receptor in tumor cell aggregates, possibly resulting in acquisition of a more aggressive phenotype via other growth factor receptors like NTR1.

View Article: PubMed Central - PubMed

Affiliation: Cluster of Translational Oncology, Ludwig Boltzmann Society, c/o Balderichgasse 26A / 7-8, A-1170 Vienna, Austria. u.olszewski@gmx.netorulrike.olszewski@toc.lbg.ac.at.

ABSTRACT
Pancreatic adenocarcinoma is a devastating disease characterized by early dissemination and poor prognosis. These solid tumors express receptors for neuropeptides like neurotensin (NT) or epidermal growth factor (EGF) and exhibit acidic regions when grown beyond a certain size. We previously demonstrated increases in intracellular Ca2+ levels, intracellular pH and interleukin-8 (IL-8) secretion in BxPC-3 and PANC-1 pancreatic cancer cells in response to a stable NT analog. The present study aimed at investigation of the dependence of the relative expression of NT receptor 1 (NTR1) and EGFR in BxPC-3 and MIA PaCa-2 cells on cell density and extracellular pH (pHe). MTT assays revealed the NTR1 inhibitor SR 142948-sensitive Lys8-ψ-Lys9NT (8-13)-induced proliferation in BxPC-3 and PANC-1 cells. Confluent cultures of BxPC3 and HT-29 lines exhibited highest expression of NTR1 and lowest of EGFR and expression of NTR1 was maximal at slightly acidic pHe. IL-8 production was stimulated by Lys8-ψ-Lys9NT (8-13) and even enhanced at both acidic and alkaline pHe in BxPC-3 and PANC-1 cells. In conclusion, our in vitro study suggests that one contributing factor to the minor responses obtained with EGFR-directed therapy may be downregulation of this receptor in tumor cell aggregates, possibly resulting in acquisition of a more aggressive phenotype via other growth factor receptors like NTR1.

No MeSH data available.


Related in: MedlinePlus

Dependence of the cell cycle distribution of BxPC-3 (top), MIA PaCa-2 (middle) and HT-29 (bottom) cells on the cell layer density. Data are presented as mean ± SD of duplicate measurements (differences in cell cycle phases to lowest density: * p < 0.05).
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f2-cancers-03-00182: Dependence of the cell cycle distribution of BxPC-3 (top), MIA PaCa-2 (middle) and HT-29 (bottom) cells on the cell layer density. Data are presented as mean ± SD of duplicate measurements (differences in cell cycle phases to lowest density: * p < 0.05).

Mentions: To investigate a putative correlation between cell cycle distribution and cell density, cells were seeded into six-well plates at increasing cell numbers and incubated in serum-supplemented culture medium until the cell layers in wells with highest cell numbers reached almost 100% of confluence. Figure 2 shows the dependence of the cell cycle distribution of BxPC-3, MIA PaCa-2 and HT-29 cells on the culture density. After an initial lag phase, BxPC-3 cells exhibited a considerable increase of cells in S phase with a maximum of DNA synthesis at 54% of confluence, followed by an increase of quiescent cells at high densities. MIA PaCa-2 cells, growing as scattered single cells, showed a large S phase fraction in highly dense cultures. Similar to BxPC-3 cells, proliferation of HT-29 cells was low during the lag phase and reached a maximum at approximately 28%, followed by a decrease of S phase cells in dense monolayers. According to these results, the different cell lines seem to become partially arrested at the S/G2M transition.


Dependence of Relative Expression of NTR1 and EGFR on Cell Density and Extracellular pH in Human Pancreatic Cancer Cell Lines.

Olszewski-Hamilton U, Hamilton G - Cancers (Basel) (2011)

Dependence of the cell cycle distribution of BxPC-3 (top), MIA PaCa-2 (middle) and HT-29 (bottom) cells on the cell layer density. Data are presented as mean ± SD of duplicate measurements (differences in cell cycle phases to lowest density: * p < 0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3756355&req=5

f2-cancers-03-00182: Dependence of the cell cycle distribution of BxPC-3 (top), MIA PaCa-2 (middle) and HT-29 (bottom) cells on the cell layer density. Data are presented as mean ± SD of duplicate measurements (differences in cell cycle phases to lowest density: * p < 0.05).
Mentions: To investigate a putative correlation between cell cycle distribution and cell density, cells were seeded into six-well plates at increasing cell numbers and incubated in serum-supplemented culture medium until the cell layers in wells with highest cell numbers reached almost 100% of confluence. Figure 2 shows the dependence of the cell cycle distribution of BxPC-3, MIA PaCa-2 and HT-29 cells on the culture density. After an initial lag phase, BxPC-3 cells exhibited a considerable increase of cells in S phase with a maximum of DNA synthesis at 54% of confluence, followed by an increase of quiescent cells at high densities. MIA PaCa-2 cells, growing as scattered single cells, showed a large S phase fraction in highly dense cultures. Similar to BxPC-3 cells, proliferation of HT-29 cells was low during the lag phase and reached a maximum at approximately 28%, followed by a decrease of S phase cells in dense monolayers. According to these results, the different cell lines seem to become partially arrested at the S/G2M transition.

Bottom Line: MTT assays revealed the NTR1 inhibitor SR 142948-sensitive Lys8-ψ-Lys9NT (8-13)-induced proliferation in BxPC-3 and PANC-1 cells.IL-8 production was stimulated by Lys8-ψ-Lys9NT (8-13) and even enhanced at both acidic and alkaline pHe in BxPC-3 and PANC-1 cells.In conclusion, our in vitro study suggests that one contributing factor to the minor responses obtained with EGFR-directed therapy may be downregulation of this receptor in tumor cell aggregates, possibly resulting in acquisition of a more aggressive phenotype via other growth factor receptors like NTR1.

View Article: PubMed Central - PubMed

Affiliation: Cluster of Translational Oncology, Ludwig Boltzmann Society, c/o Balderichgasse 26A / 7-8, A-1170 Vienna, Austria. u.olszewski@gmx.netorulrike.olszewski@toc.lbg.ac.at.

ABSTRACT
Pancreatic adenocarcinoma is a devastating disease characterized by early dissemination and poor prognosis. These solid tumors express receptors for neuropeptides like neurotensin (NT) or epidermal growth factor (EGF) and exhibit acidic regions when grown beyond a certain size. We previously demonstrated increases in intracellular Ca2+ levels, intracellular pH and interleukin-8 (IL-8) secretion in BxPC-3 and PANC-1 pancreatic cancer cells in response to a stable NT analog. The present study aimed at investigation of the dependence of the relative expression of NT receptor 1 (NTR1) and EGFR in BxPC-3 and MIA PaCa-2 cells on cell density and extracellular pH (pHe). MTT assays revealed the NTR1 inhibitor SR 142948-sensitive Lys8-ψ-Lys9NT (8-13)-induced proliferation in BxPC-3 and PANC-1 cells. Confluent cultures of BxPC3 and HT-29 lines exhibited highest expression of NTR1 and lowest of EGFR and expression of NTR1 was maximal at slightly acidic pHe. IL-8 production was stimulated by Lys8-ψ-Lys9NT (8-13) and even enhanced at both acidic and alkaline pHe in BxPC-3 and PANC-1 cells. In conclusion, our in vitro study suggests that one contributing factor to the minor responses obtained with EGFR-directed therapy may be downregulation of this receptor in tumor cell aggregates, possibly resulting in acquisition of a more aggressive phenotype via other growth factor receptors like NTR1.

No MeSH data available.


Related in: MedlinePlus