在全球范围内，乳腺癌是女性发病率与死亡率最高的癌症。乳腺癌的早期诊断、治疗和预后是一大挑战，因此确定有效的预测性诊断和预后生物标志物和药物靶点至关重要。长非编码RNA（lncRNA）基因的表达差异可能导致细胞生长失控，这种失调通常透过增殖、侵袭和迁移细胞促进肿瘤的发展。基于某些lncRNA在肿瘤组织中的特异表达，可以作为有潜力的肿瘤早期诊断和预后生物标志物。本研究使用DESeq2、edgeR方法，基于TCGA数据库来表征差异表达基因（DEG），共筛选了1067个lncRNA。利用Cox回归模型获得了43个在乳腺癌样本中与生存相关的基因，再透过Kaplan-Meier生存分析、T-test检定选出15个于三阴型乳腺癌有表达差异并且有预后意义者。其中尤其是LINC01614、LIVAR的过度表达与三阴性乳腺癌患者的低生存率密切相关，提示它们具有作为预后标志物的潜力。敲低LIVAR基因的表达显著抑制三阴性乳腺癌细胞增殖、迁移、侵袭与克隆形成能力，细胞周期蛋白激酶抑制剂p21和p27在LIVAR敲低细胞中的表达明显上调，提示LIVAR可能通过调控细胞周期影响乳腺癌细胞的增殖，发挥促癌作用。 代谢重编程是恶性肿瘤的十大特征之一，其中葡萄糖代谢异常在肿瘤细胞中尤为突出。对于癌症中代谢紊乱的认识可以揭示关键的预后标志，影响癌症诊断或治疗方法的使用。我们整合了糖酵解、柠檬酸循环等葡萄糖代谢相关通路中的基因，以GSVA、一致性聚类方法建立样本分组模型，计算相关性后筛选出409个lncRNA，它们在不同样本组别中有明显的表达差异。然后透过生存分析进一步锁定了25个lncRNA，其中C1orf50-AS1和LINC01235在乳腺癌样本中表达高且预后差，可作为潜在的乳腺癌预后标志物。 综上所述，我们通过生物信息分析方法，筛选出在乳腺癌中表达上调并且与预后相关的lncRNA分子。通过分子生物学实验发现LIVAR是一个潜在的促癌基因，通过调控细胞周期蛋白激酶抑制剂三阴性乳腺癌的增殖、迁移和侵袭，可以作为潜在的抗乳腺癌核酸药物分子靶标和预后靶点标志物。此外，我们还筛选出与糖代谢途径相关的乳腺癌预后标志物，其调控肿瘤细胞葡萄糖代谢的分子功能还有待进一步的研究。
Worldwide, breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death in women. Early diagnosis, treatment, and prognosis of breast cancer is a major challenge, so it is critical to identify effective predictive diagnostic and prognostic biomarkers and drug targets. The differential expression of long non-coding RNA (lncRNAs) genes may lead to abnormal cell division, which usually promotes the development of tumor through proliferation, invasion, and migration of cells. Based on the specific expression of some lncRNAs in tumor tissues, they can be used as potential biomarkers for early diagnosis and prognosis of tumors. In this study, DESeq2 and edgeR methods were used to characterize differentially expressed genes (DEGs) based on TCGA database, and a total of 1067 lncRNAs were screened. Using Cox regression model, 43 genes related to survival in breast cancer samples were obtained, and 15 genes with differential expression and prognostic significance in triple negative breast cancer were selected by Kaplan-Meier survival analysis and T-test. Especially, the overexpression of LINC01614 and LIVAR, were closely related to the low survival rate of triple-negative breast cancer patients, so it is suggested that they have the potential as prognostic markers. Knockdown of LIVAR gene expression significantly inhibited the proliferation, migration, invasion and colony forming of triple negative breast cancer cells. The expression of cyclin kinase inhibitors p21 and p27 in LIVAR knockdown cells was significantly up-regulated, suggesting that LIVAR may affect the proliferation of breast cancer cells through regulating cell cycle and play a role in promoting cancer. Metabolic reprogramming is one of the ten characteristics of malignant tumors, in which abnormal glucose metabolism is particularly prominent in tumor cells. Recognizing metabolic disorder in cancer could unravel key prognostic markers that can impact approaches used in cancer diagnosis and treatments. We integrated genes related to glucose metabolism pathways such as glycolysis and citric acid cycle, and established sample grouping models using GSVA and consistent clustering methods. 409 lncRNAs were screened out after correlation calculation, and their expressions showed significant differences in different sample groups. Then, 25 lncRNAs were further identified by survival analysis, among which C1orf50-AS1 and LINC01235 were highly expressed in breast cancer samples with poor prognosis, and they could be used as potential prognostic markers of breast cancer. In summary, lncRNA molecules that are up-regulated in breast cancer and associated with prognosis were screened by bioinformation analysis. Through molecular biology experiments, it is found that LIVAR is a potential oncogene through regulation of cyclin kinase inhibitors. By regulating the proliferation, migration and invasion of triple-negative breast cancer with cyclin kinase inhibitors, LIVAR can be used as a potential molecular target of anti-breast cancer nucleic acid drugs and prognostic target markers. In addition, we also screened out prognostic markers related to glucose metabolism pathways in breast cancer, whose molecular functions in regulating glucose metabolism in tumor cells remain to be further studied.
