Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA.
Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Int J Mol Sci. 2020 May 25;21(10):3722. doi: 10.3390/ijms21103722.
While pancreatic cancer (PC) survival rates have recently shown modest improvement, the disease remains largely incurable. Early detection of pancreatic cancer may result in improved outcomes and therefore, methods for early detection of cancer, even premalignant lesions, may provide more favorable outcomes. Pancreatic intraepithelial neoplasias (PanINs) have been identified as premalignant precursor lesions to pancreatic cancer. However, conventional imaging methods used for screening high-risk populations do not have the sensitivity to detect PanINs. Here, we have employed hyperpolarized metabolic imaging in vivo and nuclear magnetic resonance (H-NMR) metabolomics ex vivo to identify and understand metabolic changes, towards enabling detection of early PanINs and progression to advanced PanINs lesions that precede pancreatic cancer formation. Progression of disease from tissue containing predominantly low-grade PanINs to tissue with high-grade PanINs showed a decreasing alanine/lactate ratio from high-resolution NMR metabolomics ex vivo. Hyperpolarized magnetic resonance spectroscopy (HP-MRS) allows over 10,000-fold sensitivity enhancement relative to conventional magnetic resonance. Real-time HP-MRS was employed to measure non-invasively changes of alanine and lactate metabolites with disease progression and in control mice in vivo, following injection of hyperpolarized [1-C] pyruvate. The alanine-to-lactate signal intensity ratio was found to decrease as the disease progressed from low-grade PanINs to high-grade PanINs. The biochemical changes of alanine transaminase (ALT) and lactate dehydrogenase (LDH) enzyme activity were assessed. These results demonstrate that there are significant alterations of ALT and LDH activities during the transformation from early to advanced PanINs lesions. Furthermore, we demonstrate that real-time conversion kinetic rate constants (k and k) can be used as metabolic imaging biomarkers of pancreatic premalignant lesions. Findings from this emerging HP-MRS technique can be translated to the clinic for detection of pancreatic premalignant lesion in high-risk populations.
虽然胰腺癌(PC)的生存率最近有了适度的提高,但这种疾病在很大程度上仍然无法治愈。早期发现胰腺癌可能会带来更好的结果,因此,即使是癌前病变,癌症的早期检测方法也可能提供更有利的结果。胰腺上皮内瘤变(PanINs)已被确定为胰腺癌的癌前前驱病变。然而,用于筛查高危人群的常规成像方法没有检测 PanINs 的敏感性。在这里,我们采用了超极化代谢成像体内和核磁共振(H-NMR)代谢组学体外来识别和理解代谢变化,以实现对早期 PanINs 的检测以及进展为高级 PanINs 病变,从而形成胰腺癌。从主要包含低级别 PanINs 的组织到含有高级别 PanINs 的组织的疾病进展显示,高分辨率 NMR 代谢组学体外的丙氨酸/乳酸比值降低。与常规磁共振相比,超极化磁共振波谱(HP-MRS)允许灵敏度提高 10000 多倍。我们采用实时 HP-MRS 来测量体内注射超极化[1-C]丙酮酸后疾病进展过程中和对照小鼠中丙氨酸和乳酸代谢物的非侵入性变化。发现随着疾病从低级别 PanINs 进展到高级别 PanINs,丙氨酸到乳酸的信号强度比降低。评估了丙氨酸转氨酶(ALT)和乳酸脱氢酶(LDH)酶活性的生化变化。这些结果表明,在从早期到高级 PanINs 病变的转化过程中,ALT 和 LDH 酶活性发生了显著变化。此外,我们证明实时转换动力学速率常数(k 和 k)可作为胰腺癌前病变的代谢成像生物标志物。这项新兴的 HP-MRS 技术的研究结果可以转化为临床,用于检测高危人群中的胰腺癌前病变。