The cell line OVCAR-4 was recently ranked as one of the most representative cell lines for high grade serous ovarian cancer (HGSOC). However, little work has been done to assess the susceptibility of OVCAR-4 cells and tumors to the more common types of molecular targeting. Proteome profiles suggest OVCAR-4 express high levels of integrin αvβ3 receptors. Using flow cytometry with fluorescent antibodies we determined that OVCAR-4 cells have high number of integrin αvβ3 receptors ([9.8 ± 2.5] × 10⁴/cell) compared to the well-characterized cell line U87-MG ([5.2 ± 1.4] × 10⁴/cell). However, OVCAR-4 cells also have roughly three times the surface area of U87-MG cells, so the average αvβ3 receptor density is actually lower (11 ± 3 versus 18 ± 6 receptors/µm²). A series of new fluorescent molecular probes was prepared with structures comprised of a deep-red squaraine fluorophore (∼680 nm emission) covalently attached to zero, one, or two cyclic pentapeptide cRGD sequences for integrin targeting. Microscopy studies showed that uptake of the divalent probe into cultured OVCAR-4 cells was 2.2 ± 0.4 higher than the monovalent probe, which in turn was 2.2 ± 0.4 higher than the untargeted probe. This probe targeting trend was also seen in OVCAR-4 mouse tumor models. The results suggest that clinically relevant OVCAR-4 cells can be targeted using molecular probes based on αvβ3 integrin receptor antagonists such as the cRGD peptide. Furthermore, deep-red fluorescent cRGD-squaraine probes have potential as targeted stains of cancerous tissue associated with HGSOC in surgery and pathology settings.

OVCAR-4细胞系最近被评为高度浆液性卵巢癌（HGSOC）最具代表性的细胞系之一。但是，很少有工作来评估OVCAR-4细胞和肿瘤对更常见类型的分子靶向的敏感性。蛋白质组图谱表明OVCAR-4表达高水平的整联蛋白αvβ3受体。使用具有荧光抗体的流式细胞仪，我们确定与特征明确的细胞系U87-MG（[5.2±1.4]×）相比，OVCAR-4细胞具有大量的整合素αvβ3受体（[9.8±2.5]×10 ⁴ /细胞）。 10 ⁴ / cell）。但是，OVCAR-4细胞的表面积也大约是U87-MG细胞的三倍，因此平均αvβ3受体密度实际上较低（11±3比18±6受体/ µm ²）。制备了一系列新的荧光分子探针，其结构包括共价连接至零，一个或两个环状五肽cRGD序列以进行整联蛋白靶向的深红色方酸荧光团（约680 nm发射）。显微镜研究表明，二价探针对培养的OVCAR-4细胞的摄取比单价探针高2.2±0.4，后者比未靶向探针高2.2±0.4。在OVCAR-4小鼠肿瘤模型中也发现了这种探针靶向趋势。结果表明，可以使用基于αvβ3整联蛋白受体拮抗剂（例如cRGD肽）的分子探针靶向临床相关的OVCAR-4细胞。此外，深红色荧光cRGD-squaraine探针在手术和病理学背景中具有作为与HGSOC相关的癌组织的靶向染色剂的潜力。