BACKGROUND: Serum prostate-specific antigen (PSA) concentrations after radical prostatectomy typically become undetectable with the use of current immunometric assay methods. Despite modern surgical techniques, 15%-30% of prostate cancer patients undergoing radical prostatectomy develop a biochemical recurrence during follow-up. Unfortunately, poor analytical sensitivity of standard PSA assays delays biochemical recurrence detection, and because of day-today assay imprecision ultrasensitive PSA assays cannot assess PSA kinetics. We developed an immuno-PCR assay for total PSA that has a limit of quantification Ͼ10 times lower than current ultrasensitive assays.

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Introduction and Purpose: Triple-negative breast cancer (TNBC) accounts for 12% of breast cancers (BC) in the US and 15% worldwide. It lacks expression of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Compared to other types of BC, it is more aggressive and has higher risks of recurrence. In the metastatic setting, survival outcomes are much worse than other BC subtypes, with a 5-years survival rate of 8-16%. There is an urgent need to develop better treatment options for TNBC patients. We have developed a novel therapeutic, QN-247, by conjugating an anti-proliferative DNA aptamer to gold nanospheres. The aptamer-gold nanosphere construct shows increased half-life and cytotoxic effects relative to the aptamer alone. QN-247 inhibits nucleolin, a key regulatory protein overexpressed in triple-negative breast cancer (TNBC) cells, thereby reducing their proliferation. Description of Experimental Procedures: A subcutaneous, TNBC model (MDA-MB-231 xenograft) in nude mice was used in this efficacy study. When tumor volumes reached sufficient size (85 mm3), QN-247 test compound, aptamer alone, and vehicle control was administered daily (QD) at 1 mg/kg via intraperitoneal injection for 12 days. Tumor volumes and body weights were measured regularly through day 20. Nine animals were included in each treatment group. Summary of DataA statistically significant reduction in mean tumor volumes of QN-247 treated mice compared to the vehicle control and aptamer alone was observed. Tolerability of the QN-247 treatment was excellent with no evidence of toxicity. Statement of Conclusions: This study demonstrates that QN-247 exerts a powerful anti-tumor effect. Additional preclinical mouse xenograft tumor models will be treated with QN-247 to study its effect on other cancers. Citation Format: Tariq Arshad, Stephen Fait, Guy Gammon, Andrew Hertig, Mark J. Sarno. Nano-immunotherapy: efficacy of nanoconjugate QN-247 in a triple negative breast cancer (TNBC) mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2708.