Limits...
Dll4 blockade potentiates the anti-tumor effects of VEGF inhibition in renal cell carcinoma patient-derived xenografts.

Miles KM, Seshadri M, Ciamporcero E, Adelaiye R, Gillard B, Sotomayor P, Attwood K, Shen L, Conroy D, Kuhnert F, Lalani AS, Thurston G, Pili R - PLoS ONE (2014)

Bottom Line: Single agent treatment with REGN1035 resulted in significant tumor growth inhibition (36-62%) that was equivalent to or exceeded the single agent anti-tumor activity of the VEGF pathway inhibitors sunitinib (38-54%) and ziv-aflibercept (46%).Importantly, combination treatments with REGN1035 plus VEGF inhibitors resulted in enhanced anti-tumor effects (72-80% growth inhibition), including some tumor regression.Overall, these findings demonstrate the potent anti-tumor activity of Dll4 blockade in RCC patient-derived tumors and a combination benefit for the simultaneous targeting of the Dll4 and VEGF signaling pathways, highlighting the therapeutic potential of this treatment modality in RCC.

View Article: PubMed Central - PubMed

Affiliation: Genitourinary Program, Roswell Park Cancer Institute, Buffalo, New York, United States of America.

ABSTRACT

Background: The Notch ligand Delta-like 4 (Dll4) is highly expressed in vascular endothelium and has been shown to play a pivotal role in regulating tumor angiogenesis. Blockade of the Dll4-Notch pathway in preclinical cancer models has been associated with non-productive angiogenesis and reduced tumor growth. Given the cross-talk between the vascular endothelial growth factor (VEGF) and Delta-Notch pathways in tumor angiogenesis, we examined the activity of a function-blocking Dll4 antibody, REGN1035, alone and in combination with anti-VEGF therapy in renal cell carcinoma (RCC).

Methods and results: Severe combined immunodeficiency (SCID) mice bearing patient-derived clear cell RCC xenografts were treated with REGN1035 and in combination with the multi-targeted tyrosine kinase inhibitor sunitinib or the VEGF blocker ziv-aflibercept. Immunohistochemical and immunofluorescent analyses were carried out, as well as magnetic resonance imaging (MRI) examinations pre and 24 hours and 2 weeks post treatment. Single agent treatment with REGN1035 resulted in significant tumor growth inhibition (36-62%) that was equivalent to or exceeded the single agent anti-tumor activity of the VEGF pathway inhibitors sunitinib (38-54%) and ziv-aflibercept (46%). Importantly, combination treatments with REGN1035 plus VEGF inhibitors resulted in enhanced anti-tumor effects (72-80% growth inhibition), including some tumor regression. Magnetic resonance imaging showed a marked decrease in tumor perfusion in all treatment groups. Interestingly, anti-tumor efficacy of the combination of REGN1035 and ziv-aflibercept was also observed in a sunitinib resistant ccRCC model.

Conclusions: Overall, these findings demonstrate the potent anti-tumor activity of Dll4 blockade in RCC patient-derived tumors and a combination benefit for the simultaneous targeting of the Dll4 and VEGF signaling pathways, highlighting the therapeutic potential of this treatment modality in RCC.

Show MeSH

Related in: MedlinePlus

Effect of REGN1035 and/or anti-VEGF (sunitinib or ziv-aflibercept) on (A, B) RP-R-01 and (C) RP-R-02 tumor vasculature.Tumors from treated mice were harvested, processed, and tissue sections were stained for the differential expression of CD31 (red) for visualization of endothelial cells (left panels). (D, E, F) Blinded quantitative analysis of CD31 (right panels). Results are expressed as mean percentage positive stained area ± S.E. *p<0.05 using adjusted t-test analysis.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4231048&req=5

pone-0112371-g004: Effect of REGN1035 and/or anti-VEGF (sunitinib or ziv-aflibercept) on (A, B) RP-R-01 and (C) RP-R-02 tumor vasculature.Tumors from treated mice were harvested, processed, and tissue sections were stained for the differential expression of CD31 (red) for visualization of endothelial cells (left panels). (D, E, F) Blinded quantitative analysis of CD31 (right panels). Results are expressed as mean percentage positive stained area ± S.E. *p<0.05 using adjusted t-test analysis.

Mentions: We assessed the anti-vascular effects of anti-Dll4 and anti-VEGF treatment in our RCC models using immunofluorescence, immunohistochemistry, and non-invasive magnetic resonance imaging (MRI). The panel of images shown in Figure 4 represents immunofluorescence staining of end-of-treatment tumor sections [RP-R-01 (A and B), RP-R-02 (C)] with anti-CD31 antibody. A reduction in vessel density was observed following single agent treatment with sunitinib (34% and 85% reduction in RP-R-01, p<0.01 and RP-R-02, respectively) and ziv-aflibercept (14% reduction in RP-R-01) (Fig. 4D–F). Tumors treated with single agent REGN1035, in contrast, showed a statistically significant increase in vascular structures, as compared to vehicle (111% and 180% increase in RP-R-01, p<0.01; 22% increase in RP-R-02). This increase in tumor microvascular density is consistent with the observed increase in Ki67 staining shown in Figure 3. In addition, REGN1035 treatment promoted structural changes within the tumor vasculature with the appearance of extensively unorganized aberrant networks of small, highly branched vessels. Combination treatment resulted in significantly less tumor vascularity (50% and 68% reduction in RP-R-01; 49% reduction in RP-R-02, p<0.05), with a great percentage of the tissue nearly devoid of vascular networks.


Dll4 blockade potentiates the anti-tumor effects of VEGF inhibition in renal cell carcinoma patient-derived xenografts.

Miles KM, Seshadri M, Ciamporcero E, Adelaiye R, Gillard B, Sotomayor P, Attwood K, Shen L, Conroy D, Kuhnert F, Lalani AS, Thurston G, Pili R - PLoS ONE (2014)

Effect of REGN1035 and/or anti-VEGF (sunitinib or ziv-aflibercept) on (A, B) RP-R-01 and (C) RP-R-02 tumor vasculature.Tumors from treated mice were harvested, processed, and tissue sections were stained for the differential expression of CD31 (red) for visualization of endothelial cells (left panels). (D, E, F) Blinded quantitative analysis of CD31 (right panels). Results are expressed as mean percentage positive stained area ± S.E. *p<0.05 using adjusted t-test analysis.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231048&req=5

pone-0112371-g004: Effect of REGN1035 and/or anti-VEGF (sunitinib or ziv-aflibercept) on (A, B) RP-R-01 and (C) RP-R-02 tumor vasculature.Tumors from treated mice were harvested, processed, and tissue sections were stained for the differential expression of CD31 (red) for visualization of endothelial cells (left panels). (D, E, F) Blinded quantitative analysis of CD31 (right panels). Results are expressed as mean percentage positive stained area ± S.E. *p<0.05 using adjusted t-test analysis.
Mentions: We assessed the anti-vascular effects of anti-Dll4 and anti-VEGF treatment in our RCC models using immunofluorescence, immunohistochemistry, and non-invasive magnetic resonance imaging (MRI). The panel of images shown in Figure 4 represents immunofluorescence staining of end-of-treatment tumor sections [RP-R-01 (A and B), RP-R-02 (C)] with anti-CD31 antibody. A reduction in vessel density was observed following single agent treatment with sunitinib (34% and 85% reduction in RP-R-01, p<0.01 and RP-R-02, respectively) and ziv-aflibercept (14% reduction in RP-R-01) (Fig. 4D–F). Tumors treated with single agent REGN1035, in contrast, showed a statistically significant increase in vascular structures, as compared to vehicle (111% and 180% increase in RP-R-01, p<0.01; 22% increase in RP-R-02). This increase in tumor microvascular density is consistent with the observed increase in Ki67 staining shown in Figure 3. In addition, REGN1035 treatment promoted structural changes within the tumor vasculature with the appearance of extensively unorganized aberrant networks of small, highly branched vessels. Combination treatment resulted in significantly less tumor vascularity (50% and 68% reduction in RP-R-01; 49% reduction in RP-R-02, p<0.05), with a great percentage of the tissue nearly devoid of vascular networks.

Bottom Line: Single agent treatment with REGN1035 resulted in significant tumor growth inhibition (36-62%) that was equivalent to or exceeded the single agent anti-tumor activity of the VEGF pathway inhibitors sunitinib (38-54%) and ziv-aflibercept (46%).Importantly, combination treatments with REGN1035 plus VEGF inhibitors resulted in enhanced anti-tumor effects (72-80% growth inhibition), including some tumor regression.Overall, these findings demonstrate the potent anti-tumor activity of Dll4 blockade in RCC patient-derived tumors and a combination benefit for the simultaneous targeting of the Dll4 and VEGF signaling pathways, highlighting the therapeutic potential of this treatment modality in RCC.

View Article: PubMed Central - PubMed

Affiliation: Genitourinary Program, Roswell Park Cancer Institute, Buffalo, New York, United States of America.

ABSTRACT

Background: The Notch ligand Delta-like 4 (Dll4) is highly expressed in vascular endothelium and has been shown to play a pivotal role in regulating tumor angiogenesis. Blockade of the Dll4-Notch pathway in preclinical cancer models has been associated with non-productive angiogenesis and reduced tumor growth. Given the cross-talk between the vascular endothelial growth factor (VEGF) and Delta-Notch pathways in tumor angiogenesis, we examined the activity of a function-blocking Dll4 antibody, REGN1035, alone and in combination with anti-VEGF therapy in renal cell carcinoma (RCC).

Methods and results: Severe combined immunodeficiency (SCID) mice bearing patient-derived clear cell RCC xenografts were treated with REGN1035 and in combination with the multi-targeted tyrosine kinase inhibitor sunitinib or the VEGF blocker ziv-aflibercept. Immunohistochemical and immunofluorescent analyses were carried out, as well as magnetic resonance imaging (MRI) examinations pre and 24 hours and 2 weeks post treatment. Single agent treatment with REGN1035 resulted in significant tumor growth inhibition (36-62%) that was equivalent to or exceeded the single agent anti-tumor activity of the VEGF pathway inhibitors sunitinib (38-54%) and ziv-aflibercept (46%). Importantly, combination treatments with REGN1035 plus VEGF inhibitors resulted in enhanced anti-tumor effects (72-80% growth inhibition), including some tumor regression. Magnetic resonance imaging showed a marked decrease in tumor perfusion in all treatment groups. Interestingly, anti-tumor efficacy of the combination of REGN1035 and ziv-aflibercept was also observed in a sunitinib resistant ccRCC model.

Conclusions: Overall, these findings demonstrate the potent anti-tumor activity of Dll4 blockade in RCC patient-derived tumors and a combination benefit for the simultaneous targeting of the Dll4 and VEGF signaling pathways, highlighting the therapeutic potential of this treatment modality in RCC.

Show MeSH
Related in: MedlinePlus