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- Andersson, Jennie, et al.
(author)
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In Vitro Therapy Modeling of HER2 Targeting Therapy in Disseminated Prostate Cancer
- 2014
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In: International Journal of Oncology. - : Spandidos Publications. - 1019-6439 .- 1791-2423. ; 45:5, s. 2153-2158
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Journal article (peer-reviewed)abstract
- Prostate cancer (PCa) is the most common cancer type among men. Treatments against advanced PCa are limited and in many cases only palliative. In a later, androgent independent, stage of PCa androgen receptors can be activated without interaction with ligand, i.e., by receptors of tyrosine kinase (RTK) family in the outlaw pathway. Human epidermal growth factor receptors HER2 and EGFR belong to RTK-family. HER2 is one of the main actors in the outlaw pathway with EGFR as the preferable heterodimerizing partner. We hypothesized that information on HER2 expression in advanced PCa could be useful for selection of patients for anti-RTK therapy and monitoring of therapy response. A panel of PCa cell lines (LNCap, PC3, DU-145) was subjected to a 8-week treatment using drugs influencing the RTK: trastuzumab (anti‑HER2), 17-DMAG (Hsp90 inhibitor), alone or in combination, and their HER2 and EGFR expressions were compared with non-treated cells. Treatment with trastuzumab decreased proliferation of LNCap and DU-145 cell lines, while 17-DMAG and trastuzumab/17‑DMAG combination affected all three cell lines. HER2 expression was significantly increased in PC3 cells, the most resistant cell line. On the contrary, in responding cells (LNCap and DU-145) HER2 expression decreased, accompanied by increased EGFR expression. However, additional treatment of cells with cetuximab (anti‑EGFR) did not give any additive effect to trastuzumab. In this study the response to anti-RTK therapy proved to vary between different PCa cell lines. We have demonstrated that RTK targeting treatments may affect the phenotypic profile of PCa tumor cells that correlates with therapy outcome. Observation of such changes during treatment could be used for monitoring and an improved therapy outcome.
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| 2. |
- Mitran, Bogdan, et al.
(author)
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Affibody-mediated imaging of EGFR expression in prostate cancer using radiocobalt-labeled DOTA-Z(EGFR:2377)
- 2019
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In: Oncology Reports. - : Spandidos Publications. - 1021-335X .- 1791-2431. ; 41:1, s. 534-542
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Journal article (peer-reviewed)abstract
- The epidermal growth factor receptor (EGFR) is often overexpressed during prostate cancer (PCa) progression towards androgen-independence after hormone therapy, but the overexpression is lower than in other types of cancers. Despite the low expression, EGFR has emerged as a promising therapeutic target for patients with castration-resistant PCa. Non-invasive methods for determination of EGFR expression in PCa can serve for patient stratification and therapy response monitoring. Radionuclide imaging probes based on affibody molecules (7 kDa) provide high contrast imaging of cancer-associated molecular targets. We hypothesized that the anti-EGFR affibody molecule DOTA-Z(EGFR:2377) labeled with Co-55 (positron-emitter, T1/2=17.5 h) would enable imaging of EGFR expression in PCa xenografts. The human PCa cell line DU-145 was used for in vitro and in vivo experiments and Co-57 was used as a surrogate for Co-55 in the present study. Binding of Co-57-DOTA-Z(EGFR:2377) to EGFR-expressing xenografts was saturable with anti-EGFR monoclonal antibody cetuximab, which would motivate the use of this tracer for monitoring the receptor occupancy during treatment. A significant dose-dependent difference in radioactivity accumulation in tumors and normal organs was observed when the biodistribution was studied 3 h after the injection of 10 and 35 mu g of Co-57-DOTA-Z(EGFR:2377): At lower doses the tumor uptake was 2-fold higher although tumor-to-organ ratios were not altered. For clinically relevant organs for PCa, tumor-to-organ ratios increased with time, and at 24 h pi were 2.2 +/- 0.5 for colon, 7 +/- 2 for muscle, and 4.0 +/- 0.7 for bones. Small animal SPECT/CT images confirmed the capacity of radiocobalt labeled DOTA-Z(EGFR:2377) to visualize EGFR expression in PCa. In conclusion, the present study demonstrated the feasibility of using the radiocobalt labeled anti-EGFR affibody conjugate Z(EGFR:2377) as an imaging agent for in vivo visualization of low EGFR-expressing tumors, like PCa, and for monitoring of receptor occupancy during cetuximab therapy as well as the importance of optimal dosing in order to achieve higher sensitivity molecular imaging.
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| 5. |
- Rosestedt, Maria, et al.
(author)
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Evaluation of a radiocobalt-labelled affibody molecule for imaging of human epidermal growth factor receptor 3 expression
- 2017
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In: International Journal of Oncology. - : Spandidos Publications. - 1019-6439 .- 1791-2423. ; 51:6, s. 1765-1774
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Journal article (peer-reviewed)abstract
- The human epidermal growth factor receptor 3 (HER3) is involved in the development of cancer resistance towards tyrosine kinase-Targeted therapies. Several HER3-Targeting therapeutics are currently under clinical evaluation. Non-invasive imaging of HER3 expression could improve patient management. Affibody molecules are small engineered scaffold proteins demonstrating superior properties as targeting probes for molecular imaging compared with monoclonal antibodies. Feasibility of in vivo HER3 imaging using affibody molecules has been previously demonstrated. Preclinical studies have shown that the contrast when imaging using anti-HER3 affibody molecules can be improved over time. We aim to develop an agent for PET imaging of HER3 expression using the long-lived positron-emitting radionuclide cobalt-55 (55Co) (T1/2=17.5 h). A long-lived cobalt isotope 57Co was used as a surrogate for 55Co in this study. The anti-HER3 affibody molecule HEHEHE-ZHER3-NOTA was labelled with radiocobalt with high yield, purity and stability. Biodistribution of 57Co-HEHEHE-ZHER3-NOTA was measured in mice bearing DU145 (prostate carcinoma) and LS174T (colorectal carcinoma) xenografts at 3 and 24 h post injection (p.i.). Tumour-To-blood ratios significantly increased between 3 and 24 h p.i. (p<0.05). At 24 h p.i., tumour-To-blood ratios were 6 for DU145 and 8 for LS174T xenografts, respectively. HER3-expressing xenografts were clearly visualized in a preclinical imaging setting already 3 h p.i., and contrast further improved at 24 h p.i. In conclusion, the radiocobalt-labelled anti-HER3 affibody molecule, HEHEHE-ZHER3-NOTA, is a promising tracer for imaging of HER3 expression in tumours.
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