Antineoplastic resistance represents a multifaceted challenge for cancer therapy and diagnostics. Extensive molecular heterogeneity, even within neoplasms of the same type, can elicit distinct outcomes of administering therapeutic pressures, frequently leading to the development of drug-resistant populations. Improved success of oncotherapies merits the exploration of precise molecular imaging technologies that can detect not only anatomical but also molecular changes in tumors and their microenvironment, early on in the treatment regimen. To this end, we developed magnetic resonance molecular imaging (MRMI) strategies to target the extracellular matrix oncoprotein, extradomain-B fibronectin (EDB-FN), for non-invasive assessment and therapeutic monitoring of drug-resistant colorectal cancer (CRC)./nMethods: Two drug-resistant CRC lines generated from parent DLD-1 and RKO cells by long-term treatment with 5ʹ-FU and 5ʹ-FU plus CB-839 respectively, were characterized for functional and gene expression changes using 3D culture, transwell invasion, qRT-PCR, and western blot assays. Contrast-enhanced MRMI of EDB-FN was performed in athymic nu/nu mice bearing subcutaneous tumor xenografts with 40 µmol/kg dose of macrocyclic ZD2-targeted contrast agent MT218 [ZD2-N₃-Gd (HP-DO3A)] on a 3T MRS 3000 scanner. Immunohistochemistry was conducted on patient specimens and xenografts using anti-EDB-FN antibody G4./nResults: Analyses of TCGA and GTEx databases revealed poor prognosis of colon cancer patients with higher levels of EDB-FN. Similarly, immunohistochemical staining of patient specimens showed increased EDB-FN expression in primary colon adenocarcinoma and hepatic metastases, but none in normal adjacent tissues. Drug-resistant DLD1-DR and RKO-DR cells were also found to demonstrate enhanced invasive potential and significantly elevated EDB-FN expression over their parent counterparts. MRMI of EDB-FN with 40 µmol/kg dose of MT218 (60% lower than the clinical dose) resulted in robust signal enhancement in the drug-resistant CRC xenografts with 84-120% increase in their contrast-to-noise ratios (CNRs) over the non-resistant counterparts. The feasibility of non-invasive therapeutic monitoring using MRMI of EDB-FN was also evaluated in drug-resistant DLD1-DR tumors treated with a pan-AKT inhibitor MK2206-HCl. The treated drug-resistant tumors failed to respond to therapy, which was accurately detected by MRMI with MT218, demonstrating higher signal enhancement and increased CNRs in the 4-week follow-up scans over the pre-treatment scans./nConclusions: EDB-FN is a promising molecular marker for assessing drug resistance. MRMI of EDB-FN with MT218 at a significantly reduced dose can facilitate effective non-invasive assessment and treatment response monitoring of drug-resistant CRC, highlighting its translational potential for active surveillance and management of CRC and other malignancies.

中文翻译：

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通过域外 B 纤连蛋白 MR 分子成像对耐药结直肠癌进行无创评估和治疗监测


抗肿瘤耐药性对癌症治疗和诊断提出了多方面的挑战。即使在同一类型的肿瘤中，广泛的分子异质性也会引起治疗压力的不同结果，常常导致耐药群体的发展。为了提高肿瘤治疗的成功率，值得探索精确的分子成像技术，这些技术不仅可以在治疗方案的早期检测肿瘤及其微环境的解剖学变化，还可以检测肿瘤及其微环境的分子变化。为此，我们开发了磁共振分子成像 (MRMI) 策略，以细胞外基质癌蛋白、域外 B 纤连蛋白 (EDB-FN) 为靶点，用于耐药结直肠癌 (CRC) 的非侵入性评估和治疗监测。/方法：分别用 5ʹ-FU 和 5ʹ-FU 加 CB-839 长期治疗，从亲代 DLD-1 和 RKO 细胞产生的两种耐药 CRC 系，使用 3D 培养、transwell 来表征功能和基因表达变化侵袭、qRT-PCR 和蛋白质印迹测定。在带有皮下肿瘤异种移植物的无胸腺 nu/nu 小鼠中使用 40 µmol/kg 剂量的大环 ZD2 靶向造影剂 MT218 [ZD2-N ₃ -Gd (HP-DO3A)] 在 3T 上进行 EDB-FN 对比增强 MRMI MRS 3000 扫描仪。使用抗 EDB-FN 抗体 G4 对患者标本和异种移植物进行免疫组织化学。/n结果： TCGA 和 GTEx 数据库的分析显示，EDB-FN 水平较高的结肠癌患者预后较差。同样，患者标本的免疫组织化学染色显示，原发性结肠腺癌和肝转移瘤中 EDB-FN 表达增加，但正常邻近组织中没有表达。 还发现耐药 DLD1-DR 和 RKO-DR 细胞比其亲代细胞表现出更强的侵袭潜力和显着升高的 EDB-FN 表达。 EDB-FN 的 MRMI 与 40 µmol/kg 剂量的 MT218（比临床剂量低 60%）导致耐药 CRC 异种移植物中信号强烈增强，其对比噪声比（CNR）增加 84-120% ）超过非电阻同行。还在使用泛 AKT 抑制剂 MK2206-HCl 治疗的耐药 DLD1-DR 肿瘤中评估了使用 EDB-FN MRMI 进行非侵入性治疗监测的可行性。治疗后的耐药肿瘤未能对治疗产生反应，MRMI 与 MT218 可以准确检测到这一点，在 4 周的随访扫描中，与治疗前扫描相比，显示出更高的信号增强和 CNR 增加。/n结论： EDB- FN 是一种很有前景的耐药性评估分子标记。大幅降低剂量的 EDB-FN 与 MT218 的 MRMI 可以促进耐药 CRC 的有效非侵入性评估和治疗反应监测，突显其在 CRC 和其他恶性肿瘤主动监测和管理方面的转化潜力。