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Expression profiling of migrated and invaded breast cancer cells predicts early metastatic relapse and reveals Krüppel-like factor 9 as a potential suppressor of invasive growth in breast cancer.

Limame R, de Beeck KO, Van Laere S, Croes L, De Wilde A, Dirix L, Van Camp G, Peeters M, De Wever O, Lardon F, Pauwels P - Oncoscience (2013)

Bottom Line: Furthermore, evaluation of the genes constituting the prognostic invasion-related gene signature revealed Krüppel-like factor 9 (KLF9) as a putative suppressor of invasive growth in breast cancer.Next to loss in invasive vs non-invasive cell lines, KLF9 also showed significantly lower expression levels in the "early" invasive cell population, in several public expression data sets and in clinical breast cancer samples when compared to normal tissue.In addition, KLF9 expression correlated inversely with mitotic activity in clinical samples, indicating anti-proliferative effects.

View Article: PubMed Central - PubMed

Affiliation: Center for Oncological Research (CORE), University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium ; These authors equally contributed to this work.

ABSTRACT
Cell motility and invasion initiate metastasis. However, only a subpopulation of cancer cells within a tumor will ultimately become invasive. Due to this stochastic and transient nature, in an experimental setting, migrating and invading cells need to be isolated from the general population in order to study the gene expression profiles linked to these processes. This report describes microarray analysis on RNA derived from migrated or invaded subpopulations of triple negative breast cancer cells in a Transwell set-up, at two different time points during motility and invasion, pre-determined as "early" and "late" in real-time kinetic assessments. Invasion- and migration-related gene expression signatures were generated through comparison with non-invasive cells, remaining at the upper side of the Transwell membranes. Late-phase signatures of both invasion and migration indicated poor prognosis in a series of breast cancer data sets. Furthermore, evaluation of the genes constituting the prognostic invasion-related gene signature revealed Krüppel-like factor 9 (KLF9) as a putative suppressor of invasive growth in breast cancer. Next to loss in invasive vs non-invasive cell lines, KLF9 also showed significantly lower expression levels in the "early" invasive cell population, in several public expression data sets and in clinical breast cancer samples when compared to normal tissue. Overexpression of EGFP-KLF9 fusion protein significantly altered morphology and blocked invasion and growth of MDA-MB-231 cells in vitro. In addition, KLF9 expression correlated inversely with mitotic activity in clinical samples, indicating anti-proliferative effects.

No MeSH data available.


Related in: MedlinePlus

KLF9 is downregulated in human breast cancerA. Scatter plot depicting normalized relative expression levels of KLF9 as detected by RT-qPCR in normal human breast samples (N=8) and breast cancer (N=22). Horizontal lines indicate the mean level of expression per group. *** P < 0.001.B. Correlation plot showing available mitotic activity indices (MAI), as assessed at diagnosis for each patient (N=18), in relationship to the normalized expression of KLF9 per sample.C. Normalized relative expression levels of KLF9, as detected by RT-qPCR in triplicates, in wild-type MDA-MB-231 cells at different degrees of confluency in culture, illustrated by phase contrast pictures below each degree. Bars: 1000μm.
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Figure 5: KLF9 is downregulated in human breast cancerA. Scatter plot depicting normalized relative expression levels of KLF9 as detected by RT-qPCR in normal human breast samples (N=8) and breast cancer (N=22). Horizontal lines indicate the mean level of expression per group. *** P < 0.001.B. Correlation plot showing available mitotic activity indices (MAI), as assessed at diagnosis for each patient (N=18), in relationship to the normalized expression of KLF9 per sample.C. Normalized relative expression levels of KLF9, as detected by RT-qPCR in triplicates, in wild-type MDA-MB-231 cells at different degrees of confluency in culture, illustrated by phase contrast pictures below each degree. Bars: 1000μm.

Mentions: To investigate the clinical relevance of the observed in vitro effects, the expression of KLF9 was assessed in normal human breast tissue and breast cancer. All breast cancer samples (N=22, mean age: 59 ± 13) showed a significantly decreased expression of KLF9 in comparison with normal breast tissue (N=8, mean age: 45 ± 16) (Fig 5A).


Expression profiling of migrated and invaded breast cancer cells predicts early metastatic relapse and reveals Krüppel-like factor 9 as a potential suppressor of invasive growth in breast cancer.

Limame R, de Beeck KO, Van Laere S, Croes L, De Wilde A, Dirix L, Van Camp G, Peeters M, De Wever O, Lardon F, Pauwels P - Oncoscience (2013)

KLF9 is downregulated in human breast cancerA. Scatter plot depicting normalized relative expression levels of KLF9 as detected by RT-qPCR in normal human breast samples (N=8) and breast cancer (N=22). Horizontal lines indicate the mean level of expression per group. *** P < 0.001.B. Correlation plot showing available mitotic activity indices (MAI), as assessed at diagnosis for each patient (N=18), in relationship to the normalized expression of KLF9 per sample.C. Normalized relative expression levels of KLF9, as detected by RT-qPCR in triplicates, in wild-type MDA-MB-231 cells at different degrees of confluency in culture, illustrated by phase contrast pictures below each degree. Bars: 1000μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4295756&req=5

Figure 5: KLF9 is downregulated in human breast cancerA. Scatter plot depicting normalized relative expression levels of KLF9 as detected by RT-qPCR in normal human breast samples (N=8) and breast cancer (N=22). Horizontal lines indicate the mean level of expression per group. *** P < 0.001.B. Correlation plot showing available mitotic activity indices (MAI), as assessed at diagnosis for each patient (N=18), in relationship to the normalized expression of KLF9 per sample.C. Normalized relative expression levels of KLF9, as detected by RT-qPCR in triplicates, in wild-type MDA-MB-231 cells at different degrees of confluency in culture, illustrated by phase contrast pictures below each degree. Bars: 1000μm.
Mentions: To investigate the clinical relevance of the observed in vitro effects, the expression of KLF9 was assessed in normal human breast tissue and breast cancer. All breast cancer samples (N=22, mean age: 59 ± 13) showed a significantly decreased expression of KLF9 in comparison with normal breast tissue (N=8, mean age: 45 ± 16) (Fig 5A).

Bottom Line: Furthermore, evaluation of the genes constituting the prognostic invasion-related gene signature revealed Krüppel-like factor 9 (KLF9) as a putative suppressor of invasive growth in breast cancer.Next to loss in invasive vs non-invasive cell lines, KLF9 also showed significantly lower expression levels in the "early" invasive cell population, in several public expression data sets and in clinical breast cancer samples when compared to normal tissue.In addition, KLF9 expression correlated inversely with mitotic activity in clinical samples, indicating anti-proliferative effects.

View Article: PubMed Central - PubMed

Affiliation: Center for Oncological Research (CORE), University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium ; These authors equally contributed to this work.

ABSTRACT
Cell motility and invasion initiate metastasis. However, only a subpopulation of cancer cells within a tumor will ultimately become invasive. Due to this stochastic and transient nature, in an experimental setting, migrating and invading cells need to be isolated from the general population in order to study the gene expression profiles linked to these processes. This report describes microarray analysis on RNA derived from migrated or invaded subpopulations of triple negative breast cancer cells in a Transwell set-up, at two different time points during motility and invasion, pre-determined as "early" and "late" in real-time kinetic assessments. Invasion- and migration-related gene expression signatures were generated through comparison with non-invasive cells, remaining at the upper side of the Transwell membranes. Late-phase signatures of both invasion and migration indicated poor prognosis in a series of breast cancer data sets. Furthermore, evaluation of the genes constituting the prognostic invasion-related gene signature revealed Krüppel-like factor 9 (KLF9) as a putative suppressor of invasive growth in breast cancer. Next to loss in invasive vs non-invasive cell lines, KLF9 also showed significantly lower expression levels in the "early" invasive cell population, in several public expression data sets and in clinical breast cancer samples when compared to normal tissue. Overexpression of EGFP-KLF9 fusion protein significantly altered morphology and blocked invasion and growth of MDA-MB-231 cells in vitro. In addition, KLF9 expression correlated inversely with mitotic activity in clinical samples, indicating anti-proliferative effects.

No MeSH data available.


Related in: MedlinePlus