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Synthesis and evaluation of tumor-homing peptides for targeting prostate cancer. Amino Acids 2021; 53:645-652. [PMID: 33846842 DOI: 10.1007/s00726-021-02971-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 03/26/2021] [Indexed: 10/21/2022]
Abstract
High toxicity caused by chemotherapeutic drugs and the acquisition of drug resistance by cancer cells are the major drawbacks in cancer therapy. A promising approach to overcome the posed barriers is conjugating tumor-homing peptides to drugs or nanocarriers. Such high-affinity peptides can specifically target surface markers overexpressed by cancer cells, ensuring a rapid and cancer-specific uptake of the drugs. Since prostate-specific membrane antigen (PSMA) is overexpressed by aggressive prostate cancer cells, targeting this surface protein with peptide conjugates can lead to the development of effective strategies against prostate cancer. In this study, we aimed to determine which PSMA-binding peptide among peptides 563, 562 and 9-mer, show the highest selectivity towards PSMA using 22Rv1 prostate cancer cells, a cell line with moderate PSMA levels. Tumor-homing peptides were synthesized by fluorenylmethoxycarbonyl-based solid-phase peptide synthesis (Fmoc-SPPS) strategy, and evaluated for their prostate cancer cell-specific targeting efficiencies by flow cytometry. Our results showed that the PSMA-binding capacity of peptide 563 was superior to those of 562, 9-mer, and 5-mer; therefore, can be utilized as a potent-targeting agent not only in the treatment of high PSMA positive but also moderate PSMA positive prostate cancer tumors.
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Stuparu AD, Meyer CA, Evans-Axelsson SL, Lückerath K, Wei LH, Kim W, Poddar S, Mona CE, Dahlbom M, Girgis MD, Radu CG, Czernin J, Slavik R. Targeted alpha therapy in a systemic mouse model of prostate cancer - a feasibility study. Theranostics 2020; 10:2612-2620. [PMID: 32194823 PMCID: PMC7052903 DOI: 10.7150/thno.42228] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/07/2020] [Indexed: 12/18/2022] Open
Abstract
225Ac-PSMA-617 targeted-therapy has demonstrated efficacy in 75-85% of patients; however, responses are not durable. We aimed to establish translatable mouse models of disseminated prostate cancer (PCa) to evaluate effectiveness of 225Ac-PSMA-617 at various disease stages. Methods: C4-2, C4-2B, or 22Rv1 cells were injected into the left ventricle of male NSG mice. Disease progression was monitored using bioluminescence imaging (BLI). For treatment, mice were injected with 40 kBq 225Ac-PSMA-617 at one (early treatment cohort) or three weeks (late treatment cohort) post-inoculation. Treatment efficacy was monitored by BLI of whole-body tumor burden. Mice were sacrificed based on body conditioning score. Results: C4-2 cells yielded metastases in liver, lungs, spleen, stomach, bones, and brain - achieving a clinically relevant model of widespread metastatic disease. The disease burden in the early treatment cohort was stable over 27 weeks in 5/9 mice and progressive in 4/9 mice. These mice were sacrificed due to brain metastases. Median survival of the late treatment cohort was superior to controls (13 vs. 7 weeks; p<0.0001) but inferior to that in the early treatment cohort (13 vs. 27 weeks; p<0.001). Late cohort mice succumbed to extensive liver involvement. The 22Rv1 and C4-2B systemic models were not used for treatment due to high kidney metastatic burden or low take rate, respectively. Conclusion: C4-2 cells reproduced metastatic cancer spread most relevantly. Early treatment with 225Ac-PSMA-617 prevented liver metastases and led to significant survival benefit. Late treatment improved survival without reducing tumor burden in the liver, the main site of metastasis. The current findings suggest that early 225Ac-PSMA-617 intervention is more efficacious in the setting of widespread metastatic PCa.
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Affiliation(s)
- Andreea D. Stuparu
- Ahmanson Translational Theranostic Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), CA, USA
| | - Catherine A.L. Meyer
- Ahmanson Translational Theranostic Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), CA, USA
| | - Susan L. Evans-Axelsson
- Department of Translational Medicine, Division of Urological Cancers, Skåne University Hospital Malmö, Lund University, Sweden
| | - Katharina Lückerath
- Ahmanson Translational Theranostic Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), CA, USA
| | - Liu H. Wei
- Ahmanson Translational Theranostic Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), CA, USA
| | - Woosuk Kim
- Ahmanson Translational Theranostic Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), CA, USA
| | - Soumya Poddar
- Ahmanson Translational Theranostic Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), CA, USA
| | - Christine E. Mona
- Ahmanson Translational Theranostic Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), CA, USA
| | - Magnus Dahlbom
- Ahmanson Translational Theranostic Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), CA, USA
| | - Mark D. Girgis
- Department of Surgery, David Geffen School of Medicine at University of California, Los Angeles (UCLA), CA, USA
| | - Caius G. Radu
- Ahmanson Translational Theranostic Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), CA, USA
| | - Johannes Czernin
- Ahmanson Translational Theranostic Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), CA, USA
| | - Roger Slavik
- Ahmanson Translational Theranostic Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), CA, USA
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PSMA ligand conjugated PCL-PEG polymeric micelles targeted to prostate cancer cells. PLoS One 2014; 9:e112200. [PMID: 25386942 PMCID: PMC4227701 DOI: 10.1371/journal.pone.0112200] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 10/13/2014] [Indexed: 12/03/2022] Open
Abstract
In this content, a small molecular ligand of prostate specific membrane antigen (SMLP) conjugated poly (caprolactone) (PCL)-b-poly (ethylene glycol) (PEG) copolymers with different block lengths were synthesized to construct a satisfactory drug delivery system. Four different docetaxel-loaded polymeric micelles (DTX-PMs) were prepared by dialysis with particle sizes less than 60 nm as characterized by dynamic light scattering (DLS) and transmission electron microscope (TEM). Optimization of the prepared micelles was conducted based on short-term stability and drug-loading content. The results showed that optimized systems were able to remain stable over 7 days. Compared with Taxotere, DTX-PMs with the same ratio of hydrophilic/hydrophobic chain length displayed similar sustained release behaviors. The cytotoxicity of the optimized targeted DTX-PCL12K-PEG5K-SMLP micelles (DTX-PMs2) and non-targeted DTX-PCL12K-mPEG5K micelles (DTX-PMs1) were evaluated by MTT assays using prostate specific membrane antigen (PSMA) positive prostate adenocarcinoma cells (LNCaP). The results showed that the targeted micelles had a much lower IC50 than their non-targeted counterparts (48 h: 0.87±0.27 vs 13.48±1.03 µg/ml; 72 h: 0.02±0.008 vs 1.35±0.54 µg/ml). In vitro cellular uptake of PMs2 showed 5-fold higher fluorescence intensity than that of PMs1 after 4 h incubation. According to these results, the novel nano-sized drug delivery system based on DTX-PCL-PEG-SMLP offers great promise for the treatment of prostatic cancer.
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