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- Huhtaniemi, R., et al.
(författare)
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High intratumoral dihydrotestosterone is associated with antiandrogen resistance in VCaP prostate cancer xenografts in castrated mice
- 2022
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Ingår i: iScience. - : Elsevier BV. - 2589-0042. ; 25:5
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Tidskriftsartikel (refereegranskat)abstract
- Antiandrogen treatment resistance is a major clinical concern in castration-resistant prostate cancer (CRPC) treatment. Using xenografts of VCaP cells we showed that growth of antiandrogen resistant CRPC tumors were characterized by a higher intratumor dihydrotestosterone (DHT) concentration than that of treatment responsive tumors. Furthermore, the slow tumor growth after adrenalectomy was associated with a low intratumor DHT concentration. Reactivation of androgen signaling in enzalutamide-resistant tumors was further shown by the expression of several androgen-dependent genes. The data indicate that intratumor DHT concentration and expression of several androgen-dependent genes in CRPC lesions is an indication of enzalutamide treatment resistance and an indication of the need for further androgen blockade. The presence of an androgen synthesis, independent of CYP17A1 activity, has been shown to exist in prostate cancer cells, and thus, novel androgen synthesis inhibitors are needed for the treatment of enzalutamide-resistant CRPC tumors that do not respond to abiraterone.
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| 2. |
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| 3. |
- Bäck, Tom, 1964, et al.
(författare)
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Targeted alpha therapy with astatine-211-labeled anti-PSCA A11 minibody shows antitumor efficacy in prostate cancer xenografts and bone microtumors
- 2020
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Ingår i: Ejnmmi Research. - : Springer Science and Business Media LLC. - 2191-219X. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Targeted alpha therapy (TAT) is a promising treatment for micrometastatic and minimal residual cancer. We evaluated systemic alpha-radioimmunotherapy (alpha-RIT) of metastatic castration-resistant prostate cancer (mCRPC) using the alpha-particle emitter At-211-labeled to the anti-PSCA A11 minibody. A11 is specific for prostate stem cell antigen (PSCA), a cell surface glycoprotein which is overexpressed in more than 90% of both localized prostate cancer and bone metastases. Methods PC3-PSCA cells were implanted subcutaneously (s.c.) and intratibially (i.t) in nude mice. Efficacy of alpha-RIT (two fractions-14-day interval) was studied on s.c. macrotumors (0, 1.5 and 1.9 MBq) and on i.t. microtumors (100-200 mu m; 0, 0.8 or 1.5 MBq) by tumor-volume measurements. The injected activities for therapies were estimated from separate biodistribution and myelotoxicity studies. Results Tumor targeting of At-211-A11 was efficient and the effect on s.c. macrotumors was strong and dose-dependent. At 6 weeks, the mean tumor volumes for the treated groups, compared with controls, were reduced by approximately 85%. The separate myelotoxicity study following one single fraction showed reduced white blood cells (WBC) for all treated groups on day 6 after treatment. For the 0.8 and 1.5 MBq, the WBC reductions were transient and followed by recovery at day 13. For 2.4 MBq, a clear toxicity was observed and the mice were sacrificed on day 7. In the long-term follow-up of the 0.8 and 1.5 MBq-groups, blood counts on day 252 were normal and no signs of radiotoxicity observed. Efficacy on i.t. microtumors was evaluated in two experiments. In experiment 1, the tumor-free fraction (TFF) was 95% for both treated groups and significantly different (p < 0.05) from the controls at a TFF of 66%). In experiment 2, the difference in TFF was smaller, 32% for the treated group versus 20% for the controls. However, the difference in microtumor volume in experiment 2 was highly significant, 0.010 +/- 0.003 mm(3) versus 3.79 +/- 1.24 mm(3) (treated versus controls, respectively), i.e., a 99.7% reduction (p < 0.001). The different outcome in experiment 1 and 2 is most likely due to differences in microtumor sizes at therapy, or higher tumor-take in experiment 2 (where more cells were implanted). Conclusion Evaluating fractionated alpha-RIT with At-211-labeled anti-PSCA A11 minibody, we found clear growth inhibition on both macrotumors and intratibial microtumors. For mice treated with multiple fractions, we also observed radiotoxicity manifested by progressive loss in body weight at 30 to 90 days after treatment. Our findings are conceptually promising for a systemic TAT of mCRPC and warrant further investigations of At-211-labeled PSCA-directed vectors. Such studies should include methods to improve the therapeutic window, e.g., by implementing a pretargeted regimen of alpha-RIT or by altering the size of the targeting vector.
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| 4. |
- Thulin, T., et al.
(författare)
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Sociodemographic changes in the population frequency of colonoscopy following the implementation of organised bowel cancer screening: An analysis of data from Swedish registers, 2006-2015
- 2021
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Ingår i: Journal of Medical Screening. - : SAGE Publications. - 0969-1413 .- 1475-5793. ; 28:3, s. 244-251
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Tidskriftsartikel (refereegranskat)abstract
- Objective To assess sociodemographic changes in the population frequency of colonoscopy (PFC; number of colonoscopies per 1000 inhabitants per year) among people aged 50-74 in relation to the implementation of a regional colorectal cancer screening programme for people aged 60-69 in the Stockholm-Gotland region (RSG) in 2008. Method The PFC was estimated by year (2006-2015), pre- and post-implementation of colorectal cancer screening programme (2006-2007 vs. 2014-2015), age, sex, residential region, immigrant status and educational level. The data were obtained from Swedish patient and population registers. Results The PFC largely increased during 2006-2015 in all six Swedish regions. The estimated increase in the pre- vs. post period PFC (Delta PFC) within the RSG was (i) greater for men than for women (5.8 vs. 4.5) and (ii) smaller for people aged 70-74 than for those aged 60-69 (5.5 vs. 9.0), while the corresponding Delta PFCs within each of the other regions were (i) not greater, or even smaller, for men and (ii) not smaller, or even larger, for elderly people aged 70-74. Conclusion A regional implementation of an organised colorectal cancer screening programme did not lead to a higher PFC increase in the screening relevant age group 50-74 years. Nevertheless, changes in the PFC were more pronounced for men and less pronounced for people aged 70-74 than those invited to participate in the screening programme (60-69 years), as compared with the rest of Sweden (without organised colorectal cancer screening).
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