背景:大多数关于肿瘤从前体病变向胆囊腺癌进展的研究都是从不同患者取样的病变,提供致病级联的总体视图。这是否反映了个体患者的致瘤过程仍未充分探索。基因组和表观基因组研究表明,胆囊癌的一部分起源于胆管上皮内瘤变(BilIN)前体病变,而其他人独立于BilIN形成。缺少支持这些结论的空间转录组数据。此外,可以在同一病理样本中检测到多个具有前体或腺癌病变的区域。然而,缺乏有关此类病变的患者内部变异性的知识。
方法:为了表征个别患者胆囊癌肿瘤发生的空间转录组学,我们选择了两名具有不同病因的癌症患者,其样本同时显示多个正常上皮区域,BilIN和腺癌。使用GeoMx数字空间剖面,我们表征了两个患者中每个样本的大量感兴趣区域(ROI)的整个转录组(分别为24和32个ROI),每个ROI覆盖大约200个正常上皮细胞,低品位Bilin,高级别Bilin或腺癌。使用人胆囊类器官和细胞系衍生的肿瘤来研究基因的肿瘤促进作用。
结果:空间转录组学显示每种类型的病变都显示出有限的患者内部转录组变异性。我们的数据进一步表明,一名患者的腺癌来自高级别BilIN,另一名患者的低级别BilIN,在后一种情况下,共存的高品位Bilin通过一个独特的过程进化。两名患者在肿瘤进展过程中表现出不同的信号通路激活序列,但两个患者的信号蛋白4A(SEMA4A)表达均受到抑制。使用人类胆囊来源的类器官和细胞系来源的肿瘤,我们提供的证据表明,抑制SEMA4A可促进上皮的假分层,并增强细胞迁移和存活.
结论:胆囊腺癌可以根据患者的特定过程发展,并且注意到前体病变和癌症病变的患者内部变异性有限。我们的数据表明,抑制SEMA4A可以促进肿瘤进展。他们还强调,除了组织学信息外,还需要获得基因表达数据,以避免低估低度癌前病变的风险。
BACKGROUND: Most studies on tumour progression from precursor lesion toward gallbladder adenocarcinoma investigate lesions sampled from distinct patients, providing an overarching view of pathogenic cascades. Whether this reflects the tumourigenic process in individual patients remains insufficiently explored. Genomic and epigenomic studies suggest that a subset of gallbladder cancers originate from biliary intraepithelial neoplasia (BilIN) precursor lesions, whereas others form independently from BilINs. Spatial transcriptomic data supporting these conclusions are missing. Moreover, multiple areas with precursor or adenocarcinoma lesions can be detected within the same pathological sample. Yet, knowledge about intra-patient variability of such lesions is lacking.
METHODS: To characterise the spatial transcriptomics of gallbladder cancer tumourigenesis in individual patients, we selected two patients with distinct cancer aetiology and whose samples simultaneously displayed multiple areas of normal epithelium, BilINs and adenocarcinoma. Using GeoMx digital spatial profiling, we characterised the whole transcriptome of a high number of regions of interest (ROIs) per sample in the two patients (24 and 32 ROIs respectively), with each ROI covering approximately 200 cells of normal epithelium, low-grade BilIN, high-grade BilIN or adenocarcinoma. Human gallbladder organoids and cell line-derived tumours were used to investigate the tumour-promoting role of genes.
RESULTS: Spatial transcriptomics revealed that each type of lesion displayed limited intra-patient transcriptomic variability. Our data further suggest that adenocarcinoma derived from high-grade BilIN in one patient and from low-grade BilIN in the other patient, with co-existing high-grade BilIN evolving via a distinct process in the latter
case. The two patients displayed distinct sequences of signalling pathway activation during tumour progression, but Semaphorin 4 A (SEMA4A) expression was repressed in both patients. Using human gallbladder-derived organoids and cell line-derived tumours, we provide evidence that repression of SEMA4A promotes pseudostratification of the epithelium and enhances cell migration and survival.
CONCLUSIONS: Gallbladder adenocarcinoma can develop according to patient-specific processes, and limited intra-patient variability of precursor and cancer lesions was noticed. Our data suggest that repression of SEMA4A can promote tumour progression. They also highlight the need to gain gene expression data in addition to histological information to avoid understimating the risk of low-grade preneoplastic lesions.