Limits...
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

Proliferative responses of BxPC-3 (top), MIA PaCa-2 (middle) and HT-29 (bottom) cells to Lys8-ψ-Lys9NT(8–13) alone or in combination with 20 μM SR 142948 obtained by MTT proliferation assays after seven days of incubation. Data are presented as mean ± SD of duplicate measurements (differences to medium control and between NT- and NT/SR 142948-supplemented cultures: * p < 0.05).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3756355&req=5

f1-cancers-03-00182: Proliferative responses of BxPC-3 (top), MIA PaCa-2 (middle) and HT-29 (bottom) cells to Lys8-ψ-Lys9NT(8–13) alone or in combination with 20 μM SR 142948 obtained by MTT proliferation assays after seven days of incubation. Data are presented as mean ± SD of duplicate measurements (differences to medium control and between NT- and NT/SR 142948-supplemented cultures: * p < 0.05).

Mentions: Cell proliferation was assessed in MTT proliferation assays by incubation of cells with two-fold dilutions of Lys8-ψ-Lys9NT (8–13) at concentrations ranging from 0.07–16.67 nM under serum-free conditions for seven days. Dose-response curves for Lys8-ψ-Lys9NT (8-13) and BxPC-3, MIA PaCa-2 and HT-29 cells are shown in Figure 1. Proliferation of BxPC-3 cells was significantly stimulated by 0.07–1.04 nM Lys8-ψ-Lys9NT (8–13), whereas a concentration of 16.67 nM resulted in significant growth inhibition. Cell proliferation was not impaired by application of 20 μM SR 142948 in serum-free control medium alone, however, 20 μM SR 142948 in combination with Lys8-ψ-Lys9NT (8–13) revealed a dose-response relationship significantly different from NT-analog-stimulated growth over the whole concentration range, except at 8.3 nM Lys8-ψ-Lys9NT (8–13). Differences in the growth of MIA PaCa-2 cells treated with 0.07–16.67 nM Lys8-ψ-Lys9NT (8–13) and 20 μM SR 142948, either alone or in combination, were not significantly different from basal cell proliferation over the whole concentration range. NTR1-positive HT-29 colon cancer cells revealed increased growth at concentrations of 0.07–2.08 nM Lys8-ψ-Lys9NT (8–13); however, proliferation was significantly inhibited at 16.67 nM Lys8-ψ-Lys9NT (8–13), similar to BxPC-3 cells. The presence of 20 μM SR 142948 alone did not suppress proliferation below medium control levels in HT-29 cells; however, treatment with Lys8-ψ-Lys9NT (8–13) in combination with the antagonist impeded the cell growth at concentrations of 0.07–1.04 nM Lys8-ψ-Lys9NT (8–13) significantly.


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)

Proliferative responses of BxPC-3 (top), MIA PaCa-2 (middle) and HT-29 (bottom) cells to Lys8-ψ-Lys9NT(8–13) alone or in combination with 20 μM SR 142948 obtained by MTT proliferation assays after seven days of incubation. Data are presented as mean ± SD of duplicate measurements (differences to medium control and between NT- and NT/SR 142948-supplemented cultures: * p < 0.05).
© Copyright Policy
Related In: Results  -  Collection

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

f1-cancers-03-00182: Proliferative responses of BxPC-3 (top), MIA PaCa-2 (middle) and HT-29 (bottom) cells to Lys8-ψ-Lys9NT(8–13) alone or in combination with 20 μM SR 142948 obtained by MTT proliferation assays after seven days of incubation. Data are presented as mean ± SD of duplicate measurements (differences to medium control and between NT- and NT/SR 142948-supplemented cultures: * p < 0.05).
Mentions: Cell proliferation was assessed in MTT proliferation assays by incubation of cells with two-fold dilutions of Lys8-ψ-Lys9NT (8–13) at concentrations ranging from 0.07–16.67 nM under serum-free conditions for seven days. Dose-response curves for Lys8-ψ-Lys9NT (8-13) and BxPC-3, MIA PaCa-2 and HT-29 cells are shown in Figure 1. Proliferation of BxPC-3 cells was significantly stimulated by 0.07–1.04 nM Lys8-ψ-Lys9NT (8–13), whereas a concentration of 16.67 nM resulted in significant growth inhibition. Cell proliferation was not impaired by application of 20 μM SR 142948 in serum-free control medium alone, however, 20 μM SR 142948 in combination with Lys8-ψ-Lys9NT (8–13) revealed a dose-response relationship significantly different from NT-analog-stimulated growth over the whole concentration range, except at 8.3 nM Lys8-ψ-Lys9NT (8–13). Differences in the growth of MIA PaCa-2 cells treated with 0.07–16.67 nM Lys8-ψ-Lys9NT (8–13) and 20 μM SR 142948, either alone or in combination, were not significantly different from basal cell proliferation over the whole concentration range. NTR1-positive HT-29 colon cancer cells revealed increased growth at concentrations of 0.07–2.08 nM Lys8-ψ-Lys9NT (8–13); however, proliferation was significantly inhibited at 16.67 nM Lys8-ψ-Lys9NT (8–13), similar to BxPC-3 cells. The presence of 20 μM SR 142948 alone did not suppress proliferation below medium control levels in HT-29 cells; however, treatment with Lys8-ψ-Lys9NT (8–13) in combination with the antagonist impeded the cell growth at concentrations of 0.07–1.04 nM Lys8-ψ-Lys9NT (8–13) significantly.

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