11 research outputs found
Profiling of chemonaive osteosarcoma and paired-normal cells identifies EBF2 as a mediator of osteoprotegerin inhibition to tumor necrosis factor–related apoptosis-inducing ligand–induced apoptosis
Osteosarcoma is the most prevalent bone tumor in children and
adolescents. At present, the mechanisms of initiation, maintenance, and
metastasis are poorly understood. The purpose of this study was to identify
relevant molecular targets in the pathogenesis of osteosarcoma. EXPERIMENTAL
DESIGN: Tumor chemonaive osteoblastic populations and paired control normal
osteoblasts were isolated and characterized phenotypically from seven
osteosarcoma patients. Global transcriptomic profiling was analyzed by robust
microarray analysis. Candidate genes were confirmed by real-time PCR and
organized in molecular pathways. EBF2 and osteoprotegerin (OPG) levels were
determined by real-time PCR and OPG protein levels were assessed by ELISA.
Immunohistochemical analysis was done in a panel of 46 osteosarcoma samples.
Silencing of EBF2 was achieved by lentiviral transduction of short hairpin RNA.
Apoptosis was determined by caspase-3/7 activity. RESULTS: A robust clustered
transcriptomic signature was obtained in osteosarcoma. Transcription factor EBF2,
a known functional bone regulator, was among the most significantly overexpressed
genes. Immunohistochemical analysis showed that osteosarcoma is expressed in
approximately 70% of tumors analyzed. Because EBF2 was shown previously to act as
a transcriptional activator of OPG, elevated levels of EBF2 were associated with
high OPG protein levels in osteosarcoma samples compared with normal osteoblastic
cells. Knockdown of EBF2 led to stunted abrogation of OPG levels and increased
sensitivity to tumor necrosis factor-related apoptosis-inducing ligand
(TRAIL)-induced apoptosis. CONCLUSIONS: These findings suggest that EBF2
represents a novel marker of osteosarcoma. EBF2 up-regulation may be one of the
mechanisms involved in the high levels of OPG in osteosarcoma, contributing to
decrease TRAIL-induced apoptosis and leading to TRAIL resistance
Cortactin (CTTN) overexpression in osteosarcoma correlates with advanced stage and reduced survival
The cortactin (CTTN) gene has been found, by transcriptomic
profiling, to be overexpressed in pediatric osteosarcoma. The location of CTTN at
11q13 and the role of cortactin in cytoskeleton restructuring make CTTN of
interest as a potential biomarker for osteosarcoma. MATERIALS AND METHODS:
Osteoblasts were isolated from 20 high-grade osteosarcomas before chemotherapy,
and paired with cell samples from normal tissue, prior to RNA expression analysis
on HG-U133A chips (Affymetrix). Semiquantitative CTTN mRNA expression was
analyzed by real-time PCR. An osteosarcoma tissue microarray (TMA) containing 233
tissue spots from 48 patients was used for an immunohistochemical (IHC) study of
cortactin. RESULTS: Transcriptomic profiling and real-time PCR analysis indicated
increased CTTN expression in osteosarcomas (p = 0.001, Student's T test). TMA IHC
showed cortactin to be present more frequently and in greater abundance in
osteosarcomas than non-tumoral osteoblastic samples (p< 0.006, Mann-Withney
test). Analysis of clinical outcomes indicated that overall survival for patients
with primary tumors positive for cortactin was significantly lower than that for
patients with cortactin negative (or only weakly staining) tumors (p = 0.0278,
Log-rank test). CONCLUSIONS: Our preliminary data support the hypothesis that
over-expression of cortactin, contained in the 11q13 amplicon, is involved in
osteosarcoma carcinogenesis. The potential of cortactin overexpression as a
biomarker for osteosarcoma is consolidated
An integrative approach unveils FOSL1 as an oncogene vulnerability in KRAS-driven lung and pancreatic cancer
KRAS mutated tumours represent a large fraction of human cancers, but the vast majority remains refractory to current clinical therapies. Thus, a deeper understanding of the molecular mechanisms triggered by KRAS oncogene may yield alternative therapeutic strategies. Here we report the identification of a common transcriptional signature across mutant KRAS cancers of distinct tissue origin that includes the transcription factor FOSL1. High FOSL1 expression identifies mutant KRAS lung and pancreatic cancer patients with the worst survival outcome. Furthermore, FOSL1 genetic inhibition is detrimental to both KRAS-driven tumour types. Mechanistically, FOSL1 links the KRAS oncogene to components of the mitotic machinery, a pathway previously postulated to function orthogonally to oncogenic KRAS. FOSL1 targets include AURKA, whose inhibition impairs viability of mutant KRAS cells. Lastly, combination of AURKA and MEK inhibitors induces a deleterious effect on mutant KRAS cells. Our findings unveil KRAS downstream effectors that provide opportunities to treat KRAS-driven cancers
Novel alternatively spliced ADAM8 isoforms contribute to the aggressive bone metastatic phenotype of lung cancer
ADAMs (a disintegrin and metalloprotease) are transmembrane
proteins involved in a variety of physiological
processes and tumorigenesis. Recently, ADAM8 has been
associated with poor prognosis of lung cancer. However,
its contribution to tumorigenesis in the context of lung
cancer metastasis remains unknown. Native ADAM8
expression levels were lower in lung cancer cell lines.
In contrast, we identified and characterized two novel
spliced isoforms encoding truncated proteins, D18a and
D140, which were present in several tumor cell lines and not
in normal cells. Overexpression of D18a protein resulted in
enhanced invasive activity in vitro. ADAM8 and its D140
isoform expression levels were markedly increased in lung
cancer cells, in conditions mimicking tumor microenvironment.
Moreover, addition of supernatants from D140-overexpressing
cells resulted in a significant increase in tartrate-resistant acid
phosphataseĂľ cells in osteoclast cultures in vitro. These
findings were associated with increased pro-osteoclastogenic
cytokines interleukin (IL)-8 and IL-6 protein levels. Furthermore,
lung cancer cells overexpressing D140 increased
prometastatic activity with a high tumor burden and increased
osteolysis in a murine model of bone metastasis. Thus, the
expression of truncated forms of ADAM8 by the lung cancer
cells may result in the specific upregulation of their invasive
and osteoclastogenic activities in the bone microenvironment.
These findings suggest a novel mechanism of tumor-induced
osteolysis in metastatic bone colonization
Novel alternatively spliced ADAM8 isoforms contribute to the aggressive bone metastatic phenotype of lung cancer
ADAMs (a disintegrin and metalloprotease) are transmembrane
proteins involved in a variety of physiological
processes and tumorigenesis. Recently, ADAM8 has been
associated with poor prognosis of lung cancer. However,
its contribution to tumorigenesis in the context of lung
cancer metastasis remains unknown. Native ADAM8
expression levels were lower in lung cancer cell lines.
In contrast, we identified and characterized two novel
spliced isoforms encoding truncated proteins, D18a and
D140, which were present in several tumor cell lines and not
in normal cells. Overexpression of D18a protein resulted in
enhanced invasive activity in vitro. ADAM8 and its D140
isoform expression levels were markedly increased in lung
cancer cells, in conditions mimicking tumor microenvironment.
Moreover, addition of supernatants from D140-overexpressing
cells resulted in a significant increase in tartrate-resistant acid
phosphataseĂľ cells in osteoclast cultures in vitro. These
findings were associated with increased pro-osteoclastogenic
cytokines interleukin (IL)-8 and IL-6 protein levels. Furthermore,
lung cancer cells overexpressing D140 increased
prometastatic activity with a high tumor burden and increased
osteolysis in a murine model of bone metastasis. Thus, the
expression of truncated forms of ADAM8 by the lung cancer
cells may result in the specific upregulation of their invasive
and osteoclastogenic activities in the bone microenvironment.
These findings suggest a novel mechanism of tumor-induced
osteolysis in metastatic bone colonization
Profiling of chemonaive osteosarcoma and paired-normal cells identifies EBF2 as a mediator of osteoprotegerin inhibition to tumor necrosis factor–related apoptosis-inducing ligand–induced apoptosis
Osteosarcoma is the most prevalent bone tumor in children and
adolescents. At present, the mechanisms of initiation, maintenance, and
metastasis are poorly understood. The purpose of this study was to identify
relevant molecular targets in the pathogenesis of osteosarcoma. EXPERIMENTAL
DESIGN: Tumor chemonaive osteoblastic populations and paired control normal
osteoblasts were isolated and characterized phenotypically from seven
osteosarcoma patients. Global transcriptomic profiling was analyzed by robust
microarray analysis. Candidate genes were confirmed by real-time PCR and
organized in molecular pathways. EBF2 and osteoprotegerin (OPG) levels were
determined by real-time PCR and OPG protein levels were assessed by ELISA.
Immunohistochemical analysis was done in a panel of 46 osteosarcoma samples.
Silencing of EBF2 was achieved by lentiviral transduction of short hairpin RNA.
Apoptosis was determined by caspase-3/7 activity. RESULTS: A robust clustered
transcriptomic signature was obtained in osteosarcoma. Transcription factor EBF2,
a known functional bone regulator, was among the most significantly overexpressed
genes. Immunohistochemical analysis showed that osteosarcoma is expressed in
approximately 70% of tumors analyzed. Because EBF2 was shown previously to act as
a transcriptional activator of OPG, elevated levels of EBF2 were associated with
high OPG protein levels in osteosarcoma samples compared with normal osteoblastic
cells. Knockdown of EBF2 led to stunted abrogation of OPG levels and increased
sensitivity to tumor necrosis factor-related apoptosis-inducing ligand
(TRAIL)-induced apoptosis. CONCLUSIONS: These findings suggest that EBF2
represents a novel marker of osteosarcoma. EBF2 up-regulation may be one of the
mechanisms involved in the high levels of OPG in osteosarcoma, contributing to
decrease TRAIL-induced apoptosis and leading to TRAIL resistance
Receptor of Activated Protein C Promotes Metastasis and Correlates with Clinical Outcome in Lung Adenocarcinoma
RATIONALE: Efficient metastasis requires survival and adaptation of tumor cells to stringent conditions imposed by the extracellular milieu. Identification of critical survival signaling pathways in tumor cells might unveil novel targets relevant in disease progression.
OBJECTIVES: To investigate the contribution of activated protein C (APC) and its receptor (EPCR) in animal models of lung cancer metastasis and in patients with lung adenocarcinoma.
METHODS: Signaling pathway triggered by APC/EPCR and its relevance in apoptosis was studied in vitro. Functional significance was assessed by silencing and blocking antibodies in several in vivo models of lung cancer metastasis. We examined EPCR levels using a microarray dataset of 107 patients. Immunohistochemical analysis was performed in an independent cohort of 295 patients with lung adenocarcinoma.
MEASUREMENTS AND MAIN RESULTS: The effects of APC binding to EPCR rapidly triggered Akt and ERK signaling pathways, leading to attenuated in vitro apoptosis. In vivo, silencing of EPCR expression or blocking APC/EPCR interaction reduced homing resulting in impaired prometastatic activity. Moreover, overexpression of EPCR induced an increase metastatic activity to target organs. Analysis of clinical samples showed a robust association between high EPCR levels and poor prognosis particularly in stage I patients.
CONCLUSIONS: EPCR and its ligand APC promote cell survival that contributes to tumor cell endurance to stress favoring prometastatic activity of lung adenocarcinoma (ADC). EPCR/APC is a novel target of relevance in the clinical outcome of early-stage lung cancer
Receptor of Activated Protein C Promotes Metastasis and Correlates with Clinical Outcome in Lung Adenocarcinoma
RATIONALE: Efficient metastasis requires survival and adaptation of tumor cells to stringent conditions imposed by the extracellular milieu. Identification of critical survival signaling pathways in tumor cells might unveil novel targets relevant in disease progression.
OBJECTIVES: To investigate the contribution of activated protein C (APC) and its receptor (EPCR) in animal models of lung cancer metastasis and in patients with lung adenocarcinoma.
METHODS: Signaling pathway triggered by APC/EPCR and its relevance in apoptosis was studied in vitro. Functional significance was assessed by silencing and blocking antibodies in several in vivo models of lung cancer metastasis. We examined EPCR levels using a microarray dataset of 107 patients. Immunohistochemical analysis was performed in an independent cohort of 295 patients with lung adenocarcinoma.
MEASUREMENTS AND MAIN RESULTS: The effects of APC binding to EPCR rapidly triggered Akt and ERK signaling pathways, leading to attenuated in vitro apoptosis. In vivo, silencing of EPCR expression or blocking APC/EPCR interaction reduced homing resulting in impaired prometastatic activity. Moreover, overexpression of EPCR induced an increase metastatic activity to target organs. Analysis of clinical samples showed a robust association between high EPCR levels and poor prognosis particularly in stage I patients.
CONCLUSIONS: EPCR and its ligand APC promote cell survival that contributes to tumor cell endurance to stress favoring prometastatic activity of lung adenocarcinoma (ADC). EPCR/APC is a novel target of relevance in the clinical outcome of early-stage lung cancer