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Novel receptor tyrosine kinase targeted combination therapies for imatinib-resistant gastrointestinal stromal tumors (GIST).

Mahadevan D, Theiss N, Morales C, Stejskal AE, Cooke LS, Zhu M, Kurtzman D, Swart R, Ong E, Qi W - Oncotarget (2015)

Bottom Line: GIST882 and GIST430/654 cells have an IC50 0.077 and 0.59 µM to IM respectively.GIST48 have an IC50 0.66 µM to IM, 0.91 µM to amuvatinib [AMU] and 0.67 µM to erlotinib (Erl).Synergistic combinations: GIST882, AMU + Erl (CI 0.20); IM + AMU (CI 0.50), GIST430/654, IM + afatinib (CI 0.39); IM + AMU (CI 0.42), GIST48, IM + afatinib (CI 0.03); IM + AMU (CI 0.04); AMU + afatinib (CI 0.36); IM + Erl (CI 0.63).

View Article: PubMed Central - PubMed

Affiliation: West Cancer Center/University of Tennessee Health Science Center (UTHSC), Memphis, TN.

ABSTRACT

Background: c-Kit/α-PDGFR targeted therapies are effective for gastrointestinal stromal tumors (GIST), but, >50% develop drug resistance.

Methods: RTK expression (c-Kit, c-Met, AXL, HER-1, HER-2, IGF-1R) in pre-/post-imatinib (IM) GIST patient samples (n=16) and 4 GIST cell lines were examined for RTK inhibitor activity. GIST-882 cells were cultured in IM every other day, cells collected (1 week to 6 months) and analyzed by qRT-PCR and Western blotting.

Results: Immunohistochemistry pre-/post-IM demonstrated continued expression of c-Kit and HER1, while a subset expressed IGF-1R, c-Met and AXL. In GIST cells (GIST-882, GIST430/654, GIST48) c-Kit, HER1 and c-Met are co-expressed. Acute IM over-express c-Kit while chronic IM, lose c-Kit and HER-1 in GIST882 cells. GIST882 and GIST430/654 cells have an IC50 0.077 and 0.59 µM to IM respectively. GIST48 have an IC50 0.66 µM to IM, 0.91 µM to amuvatinib [AMU] and 0.67 µM to erlotinib (Erl). Synergistic combinations: GIST882, AMU + Erl (CI 0.20); IM + AMU (CI 0.50), GIST430/654, IM + afatinib (CI 0.39); IM + AMU (CI 0.42), GIST48, IM + afatinib (CI 0.03); IM + AMU (CI 0.04); AMU + afatinib (CI 0.36); IM + Erl (CI 0.63).

Conclusion: Targeting c-Kit plus HER1 or AXL/c-Met abrogates IM resistance in GIST.

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Related in: MedlinePlus

GIST48 Cells Treated with Synergistic Combinations of RTK InhibitorsGIST48 cells were treated with IM (0.6μM), amuvatinib (AMU, 1.0μM), erlotinib (0.7μM), afatinib (8.5μM), AMU (1.0μM) + erlotinib (0.7μM), IM (0.6μM) + erlotinib (0.7μM), AMU (1.0μM) + afatinib (8.5μM), IM (0.6μM) + afatinib (8.5μM) and AMU (1.0μM) + IM (0.6μM) for 1h. Western blotting was performed for c-Kit phosphorylation (Y719). GAPDH was used as loading control.
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Figure 6: GIST48 Cells Treated with Synergistic Combinations of RTK InhibitorsGIST48 cells were treated with IM (0.6μM), amuvatinib (AMU, 1.0μM), erlotinib (0.7μM), afatinib (8.5μM), AMU (1.0μM) + erlotinib (0.7μM), IM (0.6μM) + erlotinib (0.7μM), AMU (1.0μM) + afatinib (8.5μM), IM (0.6μM) + afatinib (8.5μM) and AMU (1.0μM) + IM (0.6μM) for 1h. Western blotting was performed for c-Kit phosphorylation (Y719). GAPDH was used as loading control.

Mentions: Western blotting analyses of GIST48 cells treated with synergistic combinations amuvatinib + erlotinib, or amuvatinib + afatinib or amuvatinib + IM at IC50 at 60 min indicate complete inhibition of c-Kit phosphorylation (Y719) in comparison to single agent IM, amuvatinib, erlotinin and afatinib (Figure 6). MTS cytotoxicity corroborates with in vitro phosphorylation of the c-Kit enzyme activity as a mechanism of efficacy for combination therapy.


Novel receptor tyrosine kinase targeted combination therapies for imatinib-resistant gastrointestinal stromal tumors (GIST).

Mahadevan D, Theiss N, Morales C, Stejskal AE, Cooke LS, Zhu M, Kurtzman D, Swart R, Ong E, Qi W - Oncotarget (2015)

GIST48 Cells Treated with Synergistic Combinations of RTK InhibitorsGIST48 cells were treated with IM (0.6μM), amuvatinib (AMU, 1.0μM), erlotinib (0.7μM), afatinib (8.5μM), AMU (1.0μM) + erlotinib (0.7μM), IM (0.6μM) + erlotinib (0.7μM), AMU (1.0μM) + afatinib (8.5μM), IM (0.6μM) + afatinib (8.5μM) and AMU (1.0μM) + IM (0.6μM) for 1h. Western blotting was performed for c-Kit phosphorylation (Y719). GAPDH was used as loading control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385828&req=5

Figure 6: GIST48 Cells Treated with Synergistic Combinations of RTK InhibitorsGIST48 cells were treated with IM (0.6μM), amuvatinib (AMU, 1.0μM), erlotinib (0.7μM), afatinib (8.5μM), AMU (1.0μM) + erlotinib (0.7μM), IM (0.6μM) + erlotinib (0.7μM), AMU (1.0μM) + afatinib (8.5μM), IM (0.6μM) + afatinib (8.5μM) and AMU (1.0μM) + IM (0.6μM) for 1h. Western blotting was performed for c-Kit phosphorylation (Y719). GAPDH was used as loading control.
Mentions: Western blotting analyses of GIST48 cells treated with synergistic combinations amuvatinib + erlotinib, or amuvatinib + afatinib or amuvatinib + IM at IC50 at 60 min indicate complete inhibition of c-Kit phosphorylation (Y719) in comparison to single agent IM, amuvatinib, erlotinin and afatinib (Figure 6). MTS cytotoxicity corroborates with in vitro phosphorylation of the c-Kit enzyme activity as a mechanism of efficacy for combination therapy.

Bottom Line: GIST882 and GIST430/654 cells have an IC50 0.077 and 0.59 µM to IM respectively.GIST48 have an IC50 0.66 µM to IM, 0.91 µM to amuvatinib [AMU] and 0.67 µM to erlotinib (Erl).Synergistic combinations: GIST882, AMU + Erl (CI 0.20); IM + AMU (CI 0.50), GIST430/654, IM + afatinib (CI 0.39); IM + AMU (CI 0.42), GIST48, IM + afatinib (CI 0.03); IM + AMU (CI 0.04); AMU + afatinib (CI 0.36); IM + Erl (CI 0.63).

View Article: PubMed Central - PubMed

Affiliation: West Cancer Center/University of Tennessee Health Science Center (UTHSC), Memphis, TN.

ABSTRACT

Background: c-Kit/α-PDGFR targeted therapies are effective for gastrointestinal stromal tumors (GIST), but, >50% develop drug resistance.

Methods: RTK expression (c-Kit, c-Met, AXL, HER-1, HER-2, IGF-1R) in pre-/post-imatinib (IM) GIST patient samples (n=16) and 4 GIST cell lines were examined for RTK inhibitor activity. GIST-882 cells were cultured in IM every other day, cells collected (1 week to 6 months) and analyzed by qRT-PCR and Western blotting.

Results: Immunohistochemistry pre-/post-IM demonstrated continued expression of c-Kit and HER1, while a subset expressed IGF-1R, c-Met and AXL. In GIST cells (GIST-882, GIST430/654, GIST48) c-Kit, HER1 and c-Met are co-expressed. Acute IM over-express c-Kit while chronic IM, lose c-Kit and HER-1 in GIST882 cells. GIST882 and GIST430/654 cells have an IC50 0.077 and 0.59 µM to IM respectively. GIST48 have an IC50 0.66 µM to IM, 0.91 µM to amuvatinib [AMU] and 0.67 µM to erlotinib (Erl). Synergistic combinations: GIST882, AMU + Erl (CI 0.20); IM + AMU (CI 0.50), GIST430/654, IM + afatinib (CI 0.39); IM + AMU (CI 0.42), GIST48, IM + afatinib (CI 0.03); IM + AMU (CI 0.04); AMU + afatinib (CI 0.36); IM + Erl (CI 0.63).

Conclusion: Targeting c-Kit plus HER1 or AXL/c-Met abrogates IM resistance in GIST.

Show MeSH
Related in: MedlinePlus