Abstract 4656: Novel mitochondria-based targeting overcomes resistance in prostate cancer
Authors: Ou Yan , Lim Adrian , Zhai Ning , Edderkaoui Mouad , Pandol Stephen , Wang Ruoxiang , Zhang Yi 
Published: March 2024

Background: Prostate cancer (PC) is a major contributor to cancer-related mortality in men, with metastatic castration-resistant PC (mCRPC) presenting a significant obstacle due to its resistance to standard treatments. Current therapies, including nonsteroidal antiandrogens and chemotherapy drugs, provide limited effectiveness and are often accompanied by severe side effects. Recently, statins have gained attention as antitumor agents, demonstrating chemopreventive effects on a range of human cancers while maintaining a well-established safety profile. However, the use of statins as standalone treatment is limited by insufficient cancer cell targeting.

Methods: We synthesized a DZ-simvastatin (DZ-SIM) conjugate that combines a near-infrared heptamethine carbocyanine dye (DZ) with simvastatin for selective tumor cell targeting. Cancer cell survival was measured by crystal violet and MTT assay. Co-localization of DZ-SIM with mitochondria and lysosome in cells was detected under confocal microscope using Mitotracker and Lysotracker. Cellular and mitochondrial cholesterol levels were detected by LC-MS. Male nude mice were inoculated subcutaneously with 22Rv1-Luc cells as a prostate cancer xenograft mouse model. We used Swiss-PDB and Rosetta algorithms to model the structure of the OATP1B3 channel. Oxygen consumption rate and extracellular acidification rate were measured by Seahorse assay. After treatment with DZ-SIM, differentially expressed genes profiling of prostate cancer cells was performed using RNAseq.

Results: Our research demonstrates the conjugate's ability to effectively kill androgen-independent and metastatic PC cells without harming normal cells. Furthermore, DZ-SIM has been shown to kill multiple human PC cell lines, regardless of androgen receptor status or therapeutic resistance. DZ-SIM has been shown to inhibit growth in human prostate cancer cell line xenograft models. NIR fluorescence imaging showed specific localization of DZ-SIM to cancer, but not to normal cells and tissues. It could localize into cancer cells by binding the transmembrane transporter OATP to primarily target subcellular organelle mitochondria, decreasing the OCR and ECAR of cancer cells. DZ-SIM can bind to multiple cytosolic and mitochondrial proteins as detected by NIRF imaging. Cholesterol levels also decrease in whole cells and mitochondria. Ingenuity Pathway Analysis (IPA) of RNAseq showed that the four signaling pathways in the DZ-SIM treatment group are significantly enriched in genes related to cholesterol synthesis.

Conclusion: DZ-SIM specifically targets PC cells and their mitochondria, resulting in loss of mitochondrial function and consequent cell death. With a unique subcellular targeting strategy, the conjugate holds the potential to outperform existing chemotherapeutic drugs.

Citation Format: Yan Ou, Adrian Lim, Ning Zhai, Mouad Edderkaoui, Stephen Pandol, Ruoxiang Wang, Yi Zhang. Novel mitochondria-based targeting overcomes resistance in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4656.