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Identifying erlotinib-sensitive non-small cell lung carcinoma tumors in mice using [(11)C]erlotinib PET.

Abourbeh G, Itamar B, Salnikov O, Beltsov S, Mishani E - EJNMMI Res (2015)

Bottom Line: Sensitivity of each cell line to the anti-proliferative effect of erlotinib was determined in vitro.In vivo PET imaging studies following i.v. injection of [(11)C]erlotinib were carried out in nude mice bearing subcutaneous (s.c.) xenografts of the four cell lines.Cells harboring activating mutations in the EGFR TK domain (HCC827 and NCI-H3255) were approximately 1,000- and 100-fold more sensitive to erlotinib treatment in vitro, respectively, compared to the other two cell lines. [(11)C]Erlotinib PET scans could differentiate erlotinib-sensitive tumors from insensitive (QG56) or resistant (NCI-H1975) tumors already at 12 min after injection.

View Article: PubMed Central - PubMed

Affiliation: Cyclotron-Radiochemistry-MicroPET Unit, Hadassah Hebrew University Hospital, Jerusalem, 91120 Israel.

ABSTRACT

Background: Non-small cell lung carcinoma (NSCLC) represents approximately 80% of lung cancer cases, and over 60% of these tumors express the epidermal growth factor receptor (EGFR). Activating mutations in the tyrosine kinase (TK) domain of the EGFR are detected in 10% to 30% of NSCLC patients, and evidence of their presence is a prerequisite for initiation of first-line therapy with selective TK inhibitors (TKIs), such as gefitinib and erlotinib. To date, the selection of candidate patients for first-line treatment with EGFR TKIs requires an invasive tumor biopsy to affirm the mutational status of the receptor. This study was designed to evaluate whether positron emission tomography (PET) of NSCLC tumor-bearing mice using [(11)C]erlotinib could distinguish erlotinib-sensitive from erlotinib-insensitive or erlotinib-resistant tumors.

Methods: Four human NSCLC cell lines were employed, expressing either of the following forms of the EGFR: (i) the wild-type receptor (QG56 cells), (ii) a mutant with an exon 19 in-frame deletion (HCC827 cells), (iii) a mutant with the exon 21 L858R point mutation (NCI-H3255 cells), and (iv) a double mutant harboring the L858R and T790M mutations (NCI-H1975 cells). Sensitivity of each cell line to the anti-proliferative effect of erlotinib was determined in vitro. In vivo PET imaging studies following i.v. injection of [(11)C]erlotinib were carried out in nude mice bearing subcutaneous (s.c.) xenografts of the four cell lines.

Results: Cells harboring activating mutations in the EGFR TK domain (HCC827 and NCI-H3255) were approximately 1,000- and 100-fold more sensitive to erlotinib treatment in vitro, respectively, compared to the other two cell lines. [(11)C]Erlotinib PET scans could differentiate erlotinib-sensitive tumors from insensitive (QG56) or resistant (NCI-H1975) tumors already at 12 min after injection. Nonetheless, the uptake in HCC827 tumors was significantly higher than that in NCI-H3255, possibly reflecting differences in ATP and erlotinib affinities between the EGFR mutants.

Conclusions: [(11)C]Erlotinib imaging in mice differentiates erlotinib-sensitive NSCLC tumors from erlotinib-insensitive or erlotinib-resistant ones.

No MeSH data available.


Related in: MedlinePlus

Representative Western blots of four human NSCLC cell lysates comparing the extent of EGFR and phospho-EGFR expression. β-actin served as a reference for equal loading.
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Fig1: Representative Western blots of four human NSCLC cell lysates comparing the extent of EGFR and phospho-EGFR expression. β-actin served as a reference for equal loading.

Mentions: Four human NSCLC cell lines expressing different forms of the EGFR were investigated. Sensitivity of each cell line to the anti-proliferative effect of erlotinib was evaluated by methylene blue assay and is presented in Table 1. Two cell lines, HCC827 and NCI-H3255, which express activating mutations in the EGFR, were erlotinib-sensitive, having mean IC50 values of 4 and 41 nM, respectively. Two additional cell lines, QG56 (expressing wtEGFR) and NCI-H1975 (expressing the L858R + T790M point mutations), were significantly less sensitive to erlotinib treatment, with mean IC50 values of 8.9 and 4.3 μM, respectively. Thus, in vitro, NCI-H3255 and HCC827 cells were 100- to 1,000-fold more sensitive to the anti-proliferative effect of erlotinib compared to QG56 and NCI-H1975 cells. In agreement with previous reports, Western blot analysis (Figure 1) indicated that the sensitivity to erlotinib treatment could not be attributed to differences in total EGFR or EGFR-associated phosphotyrosine (PY) levels, since neither of those correlated with erlotinib sensitivity of the tested cell lines [14,32,33].Table 1


Identifying erlotinib-sensitive non-small cell lung carcinoma tumors in mice using [(11)C]erlotinib PET.

Abourbeh G, Itamar B, Salnikov O, Beltsov S, Mishani E - EJNMMI Res (2015)

Representative Western blots of four human NSCLC cell lysates comparing the extent of EGFR and phospho-EGFR expression. β-actin served as a reference for equal loading.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385014&req=5

Fig1: Representative Western blots of four human NSCLC cell lysates comparing the extent of EGFR and phospho-EGFR expression. β-actin served as a reference for equal loading.
Mentions: Four human NSCLC cell lines expressing different forms of the EGFR were investigated. Sensitivity of each cell line to the anti-proliferative effect of erlotinib was evaluated by methylene blue assay and is presented in Table 1. Two cell lines, HCC827 and NCI-H3255, which express activating mutations in the EGFR, were erlotinib-sensitive, having mean IC50 values of 4 and 41 nM, respectively. Two additional cell lines, QG56 (expressing wtEGFR) and NCI-H1975 (expressing the L858R + T790M point mutations), were significantly less sensitive to erlotinib treatment, with mean IC50 values of 8.9 and 4.3 μM, respectively. Thus, in vitro, NCI-H3255 and HCC827 cells were 100- to 1,000-fold more sensitive to the anti-proliferative effect of erlotinib compared to QG56 and NCI-H1975 cells. In agreement with previous reports, Western blot analysis (Figure 1) indicated that the sensitivity to erlotinib treatment could not be attributed to differences in total EGFR or EGFR-associated phosphotyrosine (PY) levels, since neither of those correlated with erlotinib sensitivity of the tested cell lines [14,32,33].Table 1

Bottom Line: Sensitivity of each cell line to the anti-proliferative effect of erlotinib was determined in vitro.In vivo PET imaging studies following i.v. injection of [(11)C]erlotinib were carried out in nude mice bearing subcutaneous (s.c.) xenografts of the four cell lines.Cells harboring activating mutations in the EGFR TK domain (HCC827 and NCI-H3255) were approximately 1,000- and 100-fold more sensitive to erlotinib treatment in vitro, respectively, compared to the other two cell lines. [(11)C]Erlotinib PET scans could differentiate erlotinib-sensitive tumors from insensitive (QG56) or resistant (NCI-H1975) tumors already at 12 min after injection.

View Article: PubMed Central - PubMed

Affiliation: Cyclotron-Radiochemistry-MicroPET Unit, Hadassah Hebrew University Hospital, Jerusalem, 91120 Israel.

ABSTRACT

Background: Non-small cell lung carcinoma (NSCLC) represents approximately 80% of lung cancer cases, and over 60% of these tumors express the epidermal growth factor receptor (EGFR). Activating mutations in the tyrosine kinase (TK) domain of the EGFR are detected in 10% to 30% of NSCLC patients, and evidence of their presence is a prerequisite for initiation of first-line therapy with selective TK inhibitors (TKIs), such as gefitinib and erlotinib. To date, the selection of candidate patients for first-line treatment with EGFR TKIs requires an invasive tumor biopsy to affirm the mutational status of the receptor. This study was designed to evaluate whether positron emission tomography (PET) of NSCLC tumor-bearing mice using [(11)C]erlotinib could distinguish erlotinib-sensitive from erlotinib-insensitive or erlotinib-resistant tumors.

Methods: Four human NSCLC cell lines were employed, expressing either of the following forms of the EGFR: (i) the wild-type receptor (QG56 cells), (ii) a mutant with an exon 19 in-frame deletion (HCC827 cells), (iii) a mutant with the exon 21 L858R point mutation (NCI-H3255 cells), and (iv) a double mutant harboring the L858R and T790M mutations (NCI-H1975 cells). Sensitivity of each cell line to the anti-proliferative effect of erlotinib was determined in vitro. In vivo PET imaging studies following i.v. injection of [(11)C]erlotinib were carried out in nude mice bearing subcutaneous (s.c.) xenografts of the four cell lines.

Results: Cells harboring activating mutations in the EGFR TK domain (HCC827 and NCI-H3255) were approximately 1,000- and 100-fold more sensitive to erlotinib treatment in vitro, respectively, compared to the other two cell lines. [(11)C]Erlotinib PET scans could differentiate erlotinib-sensitive tumors from insensitive (QG56) or resistant (NCI-H1975) tumors already at 12 min after injection. Nonetheless, the uptake in HCC827 tumors was significantly higher than that in NCI-H3255, possibly reflecting differences in ATP and erlotinib affinities between the EGFR mutants.

Conclusions: [(11)C]Erlotinib imaging in mice differentiates erlotinib-sensitive NSCLC tumors from erlotinib-insensitive or erlotinib-resistant ones.

No MeSH data available.


Related in: MedlinePlus