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Tumor T1 Relaxation Time for Assessing Response to Bevacizumab Anti-Angiogenic Therapy in a Mouse Ovarian Cancer Model.

Ravoori MK, Nishimura M, Singh SP, Lu C, Han L, Hobbs BP, Pradeep S, Choi HJ, Bankson JA, Sood AK, Kundra V - PLoS ONE (2015)

Bottom Line: Bevacizumab treatment resulted in tumor growth inhibition (p<0.04, n=6), confirming therapeutic efficacy.Microvessel density decreased 59% and cell proliferation (Ki67+) decreased 50% in the bevacizumab treatment group (p<.001, n=6), but not apoptosis.Findings suggest that increased tumor T1 relaxation time is associated with response to bevacizumab therapy in ovarian cancer model and might serve as an early indicator of response.

View Article: PubMed Central - PubMed

Affiliation: Department of Cancer Systems Imaging, U.T.- M.D. Anderson Cancer Center, Houston, Texas, United States of America.

ABSTRACT

Purpose: To assess whether T1 relaxation time of tumors may be used to assess response to bevacizumab anti-angiogenic therapy.

Procedures: 12 female nude mice bearing subcutaneous SKOV3ip1-LC ovarian tumors were administered bevacizumab (6.25ug/g, n=6) or PBS (control, n=6) therapy twice a week for two weeks. T1 maps of tumors were generated before, two days, and 2 weeks after initiating therapy. Tumor weight was assessed by MR and at necropsy. Histology for microvessel density, proliferation, and apoptosis was performed.

Results: Bevacizumab treatment resulted in tumor growth inhibition (p<0.04, n=6), confirming therapeutic efficacy. Tumor T1 relaxation times increased in bevacizumab treated mice 2 days and 2 weeks after initiating therapy (p<.05, n=6). Microvessel density decreased 59% and cell proliferation (Ki67+) decreased 50% in the bevacizumab treatment group (p<.001, n=6), but not apoptosis.

Conclusions: Findings suggest that increased tumor T1 relaxation time is associated with response to bevacizumab therapy in ovarian cancer model and might serve as an early indicator of response.

No MeSH data available.


Related in: MedlinePlus

Axial T2-weighted MR imaging of mice with tumors.Representative axial MR images of mice pre-therapy (A, B) or two weeks after initiation of therapy (C, D) with vehicle (A, C) or bevacizumab (B, D). Axial T1 maps of the same tumors (E, F, G, H). Representative axial MR images of mice pre-therapy (E, F) or two weeks after initiation of therapy (G, H) with vehicle (E, G) or bevacizumab (F, H).
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pone.0131095.g001: Axial T2-weighted MR imaging of mice with tumors.Representative axial MR images of mice pre-therapy (A, B) or two weeks after initiation of therapy (C, D) with vehicle (A, C) or bevacizumab (B, D). Axial T1 maps of the same tumors (E, F, G, H). Representative axial MR images of mice pre-therapy (E, F) or two weeks after initiation of therapy (G, H) with vehicle (E, G) or bevacizumab (F, H).

Mentions: We evaluated the effect of bevacizumab on tumor growth. Bevacizumab treatment inhibited tumor growth compared to the control as seen by MR imaging (Fig 1). Before therapy, there was no statistically significant difference in tumor weight between the two groups as measured on the MR images. Two days and two weeks post-treatment, mice treated with bevacizumab had significantly smaller tumors than control mice (p< 0.04, n = 6) by both in vivo MR measurement and ex vivo at necropsy (Fig 2). No difference was seen in tumor weights in the treatment groups pre-therapy versus 2 days or 2 weeks post initiation of bevacizumab therapy. Tumor weights derived from in vivo MR imaging correlated highly with the weights of excised tumors (r2 = 0.99, p<0.001, n = 12, Fig 3).


Tumor T1 Relaxation Time for Assessing Response to Bevacizumab Anti-Angiogenic Therapy in a Mouse Ovarian Cancer Model.

Ravoori MK, Nishimura M, Singh SP, Lu C, Han L, Hobbs BP, Pradeep S, Choi HJ, Bankson JA, Sood AK, Kundra V - PLoS ONE (2015)

Axial T2-weighted MR imaging of mice with tumors.Representative axial MR images of mice pre-therapy (A, B) or two weeks after initiation of therapy (C, D) with vehicle (A, C) or bevacizumab (B, D). Axial T1 maps of the same tumors (E, F, G, H). Representative axial MR images of mice pre-therapy (E, F) or two weeks after initiation of therapy (G, H) with vehicle (E, G) or bevacizumab (F, H).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4476738&req=5

pone.0131095.g001: Axial T2-weighted MR imaging of mice with tumors.Representative axial MR images of mice pre-therapy (A, B) or two weeks after initiation of therapy (C, D) with vehicle (A, C) or bevacizumab (B, D). Axial T1 maps of the same tumors (E, F, G, H). Representative axial MR images of mice pre-therapy (E, F) or two weeks after initiation of therapy (G, H) with vehicle (E, G) or bevacizumab (F, H).
Mentions: We evaluated the effect of bevacizumab on tumor growth. Bevacizumab treatment inhibited tumor growth compared to the control as seen by MR imaging (Fig 1). Before therapy, there was no statistically significant difference in tumor weight between the two groups as measured on the MR images. Two days and two weeks post-treatment, mice treated with bevacizumab had significantly smaller tumors than control mice (p< 0.04, n = 6) by both in vivo MR measurement and ex vivo at necropsy (Fig 2). No difference was seen in tumor weights in the treatment groups pre-therapy versus 2 days or 2 weeks post initiation of bevacizumab therapy. Tumor weights derived from in vivo MR imaging correlated highly with the weights of excised tumors (r2 = 0.99, p<0.001, n = 12, Fig 3).

Bottom Line: Bevacizumab treatment resulted in tumor growth inhibition (p<0.04, n=6), confirming therapeutic efficacy.Microvessel density decreased 59% and cell proliferation (Ki67+) decreased 50% in the bevacizumab treatment group (p<.001, n=6), but not apoptosis.Findings suggest that increased tumor T1 relaxation time is associated with response to bevacizumab therapy in ovarian cancer model and might serve as an early indicator of response.

View Article: PubMed Central - PubMed

Affiliation: Department of Cancer Systems Imaging, U.T.- M.D. Anderson Cancer Center, Houston, Texas, United States of America.

ABSTRACT

Purpose: To assess whether T1 relaxation time of tumors may be used to assess response to bevacizumab anti-angiogenic therapy.

Procedures: 12 female nude mice bearing subcutaneous SKOV3ip1-LC ovarian tumors were administered bevacizumab (6.25ug/g, n=6) or PBS (control, n=6) therapy twice a week for two weeks. T1 maps of tumors were generated before, two days, and 2 weeks after initiating therapy. Tumor weight was assessed by MR and at necropsy. Histology for microvessel density, proliferation, and apoptosis was performed.

Results: Bevacizumab treatment resulted in tumor growth inhibition (p<0.04, n=6), confirming therapeutic efficacy. Tumor T1 relaxation times increased in bevacizumab treated mice 2 days and 2 weeks after initiating therapy (p<.05, n=6). Microvessel density decreased 59% and cell proliferation (Ki67+) decreased 50% in the bevacizumab treatment group (p<.001, n=6), but not apoptosis.

Conclusions: Findings suggest that increased tumor T1 relaxation time is associated with response to bevacizumab therapy in ovarian cancer model and might serve as an early indicator of response.

No MeSH data available.


Related in: MedlinePlus