Supporting data for "The role of lumican in hepatocellular carcinoma"

Hepatocellular carcinoma (HCC) remains a worldwide health challenge with its incidence rising globally. Locoregional therapies is still the mainstay for HCC treatment, however, majority of the HCC patients are diagnosed at advanced stage where palliative therapies are the only options, and the rate of recurrence appears to be high. With the rapid expanding knowledge in the pathogenic mechanism of HCC, new promising therapeutic approaches including immunotherapy, targeted therapy and combination therapies have been introduced. While the emergence of these novel therapies has offered hope to HCC patients, they are effective in providing limited clinical benefit, and some are even yet to be translated into clinical setting owing to the lack of efficacy. Metastasis is a predominant cause of death in patients due to multiple organ failure, and it is often observed in patients with advanced stage HCC. Thus, the identification of key players in HCC metastasis would help discovering new potential therapeutic targets and combating HCC by filling the unmet need for effective treatment.Lumican (LUM) is an extracellular matrix protein that has a well-established role in collagen fibril assembly. In the liver, LUM was shown to be a prerequisite for hepatic fibrosis, and it was overexpressed in liver tissues of patients with chronic hepatitis B, fibrosis and non-alcoholic steatohepatitis (NASH). Intriguingly, it was revealed as a double-edged sword in cancer pathogenesis, in which it could be both pro-tumorigenic and anti-tumorigenic dependig on the tumour origin. A Chinese literature by Mu et al. demonstrated that the migratory and invasive potentials of HCC cells were attenuated by silencing the LUM gene, which implied a pro-tumorigenic role of LUM in HCC. Yet, as a secreted protein, the functional role and clinical significance of secreted LUM (sLUM) in HCC is largely unexplored. Therefore, we focused on assessing the clinical significance of sLUM in HCC and elucidating the functional implication of sLUM in the metastasis of HCC in this study.In the clinical cohorts, our study revealed that LUM was upregulated in both tumoral and non-tumoral regions of fibrotic liver tissues from HCC patients, with fibroblasts in the stromal area as a main source of sLUM. Moreover, a high serum level of LUM was associated with more aggressive pathological features of HCC and poor prognosis. It as well further stratified the overall survival of patients when used in combination with other HCC prognosticators, which suggested a potential role of sLUM as an HCC prognostic marker. At molecular level, in consistence with the clinical results, LUM was overexpressed in HCC cell lines and normal liver fibroblast (NLF), with fibroblast secreted the most abundant LUM among all human cell lines. By means of the recombinant human LUM protein (rhLUM) and the NLF-derived conditioned medium, sLUM enhanced the metastatic and self-renewal potentials of HCC which could be antagonised by the anti-LUM antibody. Similarly, through co-culture of HCC cells and LUM-knockdown NLF, the metastatic and self-renewal abilities of tumour cells was significantly reduced. In summary, sLUM is a potential therapeutic target and prognostic biomarker for HCC.

肝细胞癌（HCC）作为一种全球性的健康挑战，其发病率在全球范围内呈上升趋势。局部区域治疗仍然是HCC治疗的主要手段，然而，大多数HCC患者在晚期才被诊断出，此时仅能选择姑息治疗，且复发率较高。随着对HCC发病机制的深入研究，包括免疫治疗、靶向治疗和联合治疗在内的新兴治疗方案应运而生。尽管这些新型疗法的出现为HCC患者带来了希望，但它们在提供有限的临床效益方面有效，且一些疗法因疗效不足而尚未应用于临床。转移是导致患者多器官功能衰竭死亡的主要原因，且在晚期HCC患者中常观察到转移。因此，识别HCC转移的关键参与者有助于发现新的潜在治疗靶点，并通过满足对有效治疗的需求来对抗HCC。Lumican（LUM）是一种具有在胶原蛋白纤维组装中确立作用的细胞外基质蛋白。在肝脏中，研究表明LUM是肝纤维化的先决条件，并在慢性乙型肝炎、肝纤维化和非酒精性脂肪性肝炎（NASH）患者的肝组织中过度表达。令人惊讶的是，它在肿瘤发生学中被揭示为一把双刃剑，其作用可以是促肿瘤发生也可以是抗肿瘤发生，这取决于肿瘤的起源。Mu等人的中国文献表明，通过沉默LUM基因，HCC细胞的迁移和侵袭潜能减弱，这暗示了LUM在HCC中的促肿瘤发生作用。然而，作为一种分泌蛋白，分泌型LUM（sLUM）在HCC中的功能作用和临床意义尚未得到充分研究。因此，本研究集中评估了sLUM在HCC中的临床意义，并阐明了sLUM在HCC转移中的功能意义。在临床队列研究中，我们发现LUM在HCC患者的肿瘤和非肿瘤区域的肝纤维化组织中均上调，其中间质区的成纤维细胞是sLUM的主要来源。此外，高血清水平的LUM与HCC更具侵袭性的病理特征和不良预后相关。当与其他HCC预后指标结合使用时，LUM还能进一步分层患者的总生存期，这表明sLUM作为HCC预后标志物的潜在作用。在分子水平上，与临床结果一致，LUM在HCC细胞系和正常肝成纤维细胞（NLF）中过度表达，其中成纤维细胞分泌的LUM在所有人类细胞系中最为丰富。通过重组人LUM蛋白（rhLUM）和NLF衍生的条件培养基，sLUM增强了HCC的转移和自我更新潜能，这可以通过抗LUM抗体进行拮抗。同样，通过HCC细胞和LUM敲低NLF的共培养，肿瘤细胞的转移和自我更新能力显著降低。综上所述，sLUM是HCC的潜在治疗靶点和预后生物标志物。