Nasopharyngeal carcinoma（NPC） is a distinct type of head and neck cancer closely associated with Epstein-Barr virus（EBV） infection and exhibits significant geographic variations in its incidence. Despite recent advancements in radiotherapy techniques and precision medicine for NPC, the overall survival rate remains unsatisfactory due to tumor metastasis, recurrence, and drug resistance. Single-cell RNA sequencing（scRNA-seq） is an emerging technology that allows for the analysis of gene expression at single-cell resolution, providing a clearer understanding of tumor cell subpopulations, the evolutionary trajectory of tumor cells, and the functional roles and interactions of cells within the tumor microenvironment. This provides new ideas for the development of precision medicine in NPC. Here, we review the applications of scRNA-seq in exploring the mechanisms of NPC pathogenesis, tumor heterogeneity, the tumor microenvironment, drug resistance, and therapeutic response.
Humans ; Nasopharyngeal Neoplasms/genetics* ; Tumor Microenvironment ; Nasopharyngeal Carcinoma ; Single-Cell Analysis ; Sequence Analysis, RNA ; Precision Medicine ; Drug Resistance, Neoplasm ; Epstein-Barr Virus Infections ; Herpesvirus 4, Human ; Single-Cell Gene Expression Analysis

Dysregulated RNA splicing is a well-recognized characteristic of colorectal cancer (CRC); however, its intricacies remain obscure, partly due to challenges in profiling full-length transcript variants at the single-cell level. Here, we employ high-depth long-read scRNA-seq to define the full-length transcriptome of colorectal epithelial cells in 12 CRC patients, revealing extensive isoform diversities and splicing alterations. Cancer cells exhibited increased transcript complexity, with widespread 3'-UTR shortening and reduced intron retention. Distinct splicing regulation patterns were observed between intrinsic-consensus molecular subtypes (iCMS), with iCMS3 displaying even higher splicing factor activities and more pronounced 3'-UTR shortening. Furthermore, we revealed substantial shifts in isoform usage that result in alterations of protein sequences from the same gene with distinct carcinogenic effects during tumorigenesis of CRC. Allele-specific expression analysis revealed dominant mutant allele expression in key oncogenes and tumor suppressors. Moreover, mutated PPIG was linked to widespread splicing dysregulation, and functional validation experiments confirmed its critical role in modulating RNA splicing and tumor-associated processes. Our findings highlight the transcriptomic plasticity in CRC and suggest novel candidate targets for splicing-based therapeutic strategies.
Humans ; Colorectal Neoplasms/metabolism* ; RNA Isoforms/metabolism* ; Single-Cell Analysis ; RNA Splicing ; Gene Expression Regulation, Neoplastic ; RNA, Neoplasm/metabolism* ; Transcriptome

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy and is the fourth-leading cause of cancer-related deaths worldwide. HCC is refractory to many standard cancer treatments and the prognosis is often poor, highlighting a pressing need to identify biomarkers of aggressiveness and potential targets for future treatments. Kinesin family member 2C (KIF2C) is reported to be highly expressed in several human tumors. Nevertheless, the molecular mechanisms underlying the role of KIF2C in tumor development and progression have not been investigated. In this study, we found that KIF2C expression was significantly upregulated in HCC, and that KIF2C up-regulation was associated with a poor prognosis. Utilizing both gain and loss of function assays, we showed that KIF2C promoted HCC cell proliferation, migration, invasion, and metastasis both in vitro and in vivo. Mechanistically, we identified TBC1D7 as a binding partner of KIF2C, and this interaction disrupts the formation of the TSC complex, resulting in the enhancement of mammalian target of rapamycin complex1 (mTORC1) signal transduction. Additionally, we found that KIF2C is a direct target of the Wnt/β-catenin pathway, and acts as a key factor in mediating the crosstalk between Wnt/β-catenin and mTORC1 signaling. Thus, the results of our study establish a link between Wnt/β-catenin and mTORC1 signaling, which highlights the potential of KIF2C as a therapeutic target for the treatment of HCC.
Adult ; Aged ; Animals ; Carcinoma, Hepatocellular/pathology* ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Epithelial-Mesenchymal Transition/genetics* ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Intracellular Signaling Peptides and Proteins/metabolism* ; Kinesins/metabolism* ; Liver Neoplasms/pathology* ; Male ; Mice ; Mice, Inbred BALB C ; Middle Aged ; Neoplasm Staging ; Prognosis ; Protein Binding ; RNA, Small Interfering/metabolism* ; Survival Analysis ; Tumor Burden ; Wnt Signaling Pathway ; Xenograft Model Antitumor Assays ; beta Catenin/metabolism*

OBJECTIVE: With the emerging significance of genetic profiles in the management of endometrial cancer, the identification of tumor-driving genes with prognostic value is a pressing need. The LAMC1 gene, encoding the laminin subunit gamma 1 (LAMC1) protein, has been reported to be involved in the progression of various malignant tumors. In this study, we aimed to investigate the role of LAMC1 in endometrial cancer and elucidate the underlying mechanism.METHODS: We evaluated the immunohistochemical expression of LAMC1 in atypical endometrial hyperplasia and endometrial cancer. Within the endometrial cancer cases, we analyzed the association of LAMC1 overexpression with clinicopathological factors and prognosis. Furthermore, to indentify genes influenced by LAMC1 overexpression, we transfected HEC50B and SPAC-S cells with siRNA targeting LAMC1 and conducted microarray gene expression assays.RESULTS: While none of the atypical endometrial hyperplasia specimens exhibited LAMC1 overexpression, endometrial cancer possessed a significantly higher LAMC1 overexpression rate. LAMC1 overexpression was strongly associated with histological type, lymphovascular space invasion, lymph node metastasis, advanced International Federation of Gynecology and Obstetrics stage, and poor overall survival in endometrial cancer. Gene expression microarray analysis identified 8 genes correlated with tumor progression (LZTFL1, TAPT1, SEL1L, PAQR6, NME7, TMEM109, CCDC58, and ANKRD40) that were commonly influenced in HEC50B and SPAC-S by LAMC1 silencing.CONCLUSION: LAMC1 overexpression is a potent biomarker for identifying endometrial cancer patients needing aggressive adjuvant therapy. We elucidated 8 candidate genes that may mediate progression of LAMC1 overexpressing cancer. Further investigation of the underlying mechanism should lead to the discovery of new therapeutic targets.
Endometrial Hyperplasia ; Endometrial Neoplasms ; Female ; Gene Expression ; Gene Expression Profiling ; Gynecology ; Humans ; Laminin ; Lymph Nodes ; Microarray Analysis ; Neoplasm Metastasis ; Obstetrics ; Prognosis ; RNA, Small Interfering

Human breast cancer cell line, MDA-MB-231, is highly invasive and aggressive, compared to less invasive cell line, MCF-7. To explore the genes that might influence the malignancy of MDA-MB-231, DNA microarray analysis was performed. The results showed that G0/G1 switch 2 (G0S2) was one of the most highly expressed genes among the genes upregulated in MDA-MB-231. Although G0S2 acts as a direct inhibitor of adipose triglyceride lipase, action of G0S2 in cancer progression is not yet understood. To investigate whether G0S2 affects invasiveness of MDA-MB-231 cells, G0S2 expression was inhibited using siRNA, which led to decreased cell proliferation, migration, and invasion of MDA-MB-231 cells. Consequently, G0S2 inhibition inactivated integrin-regulated FAK-Src signaling, which promoted Hippo signaling and inactivated ERK1/2 signaling. In addition, G0S2 downregulation decreased β-catenin expression, while E-cadherin expression was increased. It was demonstrated for the first time that G0S2 mediates the Hippo pathway and induces epithelial to mesenchymal transition (EMT). Taken together, our results suggest that G0S2 is a major factor contributing to cell survival and metastasis of MDA-MB-231 cells.
Breast Neoplasms ; Breast ; Cadherins ; Cell Line ; Cell Proliferation ; Cell Survival ; Down-Regulation ; Humans ; Lipase ; Neoplasm Metastasis ; Oligonucleotide Array Sequence Analysis ; RNA, Small Interfering ; Signal Transduction

BACKGROUND: Smad3 linker phosphorylation plays essential roles in tumor progression and metastasis. We have previously reported that the mutation of Smad3 linker phosphorylation sites (Smad3-Erk/Pro-directed kinase site mutant constructs [EPSM]) markedly reduced the tumor progression while increasing the lung metastasis in breast cancer. METHODS: We performed high-throughput RNA-Sequencing of the human prostate cancer cell lines infected with adenoviral Smad3-EPSM to identify the genes regulated by Smad3-EPSM. RESULTS: In this study, we identified genes which are differentially regulated in the presence of Smad3-EPSM. We first confirmed that Smad3-EPSM strongly enhanced a capability of cell motility and invasiveness as well as the expression of epithelial-mesenchymal transition marker genes, CDH2, SNAI1, and ZEB1 in response to TGF-β1 in human pancreatic and prostate cancer cell lines. We identified GADD45B, CTGF, and JUNB genes in the expression profiles associated with cell motility and invasiveness induced by the Smad3-EPSM. CONCLUSIONS: These results suggested that inhibition of Smad3 linker phosphorylation may enhance cell motility and invasiveness by inducing expression of GADD45B, CTGF, and JUNB genes in various cancers.
Breast Neoplasms ; Cell Line ; Cell Movement ; Epithelial-Mesenchymal Transition ; Humans ; Lung ; Neoplasm Metastasis ; Pancreatic Neoplasms ; Phosphorylation ; Phosphotransferases ; Prostatic Neoplasms ; Sequence Analysis, RNA

PURPOSE: Follistatin-like protein 1 (FSTL1) is a secreted glycoprotein that has been shown to play a role in various types of cancer. However, the clinical significance and function of FSTL1 in breast cancer have not been reported. We investigated the role of FSTL1 in breast cancer in this study. METHODS: Enzyme-linked immunosorbent assays, western blot analysis, and reverse transcription polymerase chain reaction were used to monitor the expression of FSTL1 in breast cancer tissue and in serum samples from breast cancer patients. We employed a 4T1 breast cancer model and Fstl1(+/−) mice for in vivo studies. Hematoxylin and eosin staining, western blot analysis, and RNA sequencing were used to analyze the effect of FSTL1 on primary tumor growth and lung metastasis. RESULTS: We demonstrated that the expression of FSTL1 is reduced in both the breast cancer tissue and the serum of breast cancer patients. We showed that reduced levels of FSTL1 in serum correlate with elevated expression of Ki-67 and epidermal growth factor receptor (EGFR) in cancer tissues. Moreover, lowered expression of FSTL1 was associated with decreased survival in breast cancer patients. Experiments on the Fstl1(+/−) mouse model established that FSTL1 deficiency had no effect on primary tumor growth, but increased the lung metastases of breast cancer cells, resulting in reduced survival of tumor-bearing mice. RNA sequencing found significantly reduced expression of Egln3 and increased expression of EGFR in Fstl1(+/−) mice. Thus, our results suggest that FSTL1 may affect the expression of EGFR through Egln3, inhibiting the proliferation of breast cancer cells at lung metastatic sites. CONCLUSION: In conclusion, we suggest a suppressor role of FSTL1 in breast cancer lung metastasis. Furthermore, FSTL1 may represent a potential prognostic biomarker and a candidate therapeutic target in breast cancer patients.
Animals ; Blotting, Western ; Breast Neoplasms* ; Breast* ; Enzyme-Linked Immunosorbent Assay ; Eosine Yellowish-(YS) ; Follistatin-Related Proteins* ; Genes, Tumor Suppressor ; Glycoproteins ; Hematoxylin ; Humans ; Lung* ; Mice ; Neoplasm Metastasis ; Polymerase Chain Reaction ; Receptor, Epidermal Growth Factor ; Reverse Transcription ; Sequence Analysis, RNA

PURPOSE: Recent data have shown that the expression levels of long noncoding RNAs (lncRNAs) are associated with tamoxifen sensitivity in estrogen receptor (ER)-positive breast cancer. Herein, we constructed an lncRNA-based model to predict disease outcomes of ER-positive breast cancer patients treated with tamoxifen. METHODS: LncRNA expression information was acquired from Gene Expression Omnibus by re-mapping pre-existing microarrays of patients with ER-positive breast cancer treated with tamoxifen. The distant metastasis-free survival (DMFS) predictive signature was subsequently built based on a Cox proportional hazard regression model in discover cohort patients, which was further evaluated in another independent validation dataset. RESULTS: Six lncRNAs were found to be associated with DMFS in the discover cohort, which were used to construct a tamoxifen efficacy-related lncRNA signature (TLS). There were 133 and 362 patients with TLS high- and low-risk signatures in the discover cohort. Both univariate and multivariate analysis demonstrated that TLS was associated with DMFS. TLS high-risk patients had worse outcomes than low-risk patients, with a hazard ratio of 4.04 (95% confidence interval, 2.83–5.77; p < 0.001). Both subgroup analysis and receiver operating characteristic analysis indicated that TLS performed better in lymph node-negative, luminal B, 21-gene recurrence score high-risk, and 70-gene prognosis signature high-risk patients. Moreover, in a comparison of the 21-gene recurrence score and 70-gene prognosis signature, TLS showed a similar area under receiver operating characteristic curve in all patients. Gene Set Enrichment Analysis indicated that TLS high-risk patients showed different gene expression patterns related to the cell cycle and nucleotide metabolism from those of low-risk patients. CONCLUSION: This six-lncRNA signature was associated with disease outcome in ER-positive breast cancer patients treated with tamoxifen, which is comparable to previous messenger RNA signatures and requires further clinical evaluation.
Breast Neoplasms* ; Breast* ; Cell Cycle ; Cohort Studies ; Dataset ; Estrogens* ; Gene Expression ; Humans ; Metabolism ; Multivariate Analysis ; Neoplasm Metastasis ; Phenobarbital ; Prognosis ; Recurrence ; RNA, Long Noncoding* ; RNA, Messenger ; ROC Curve ; Tamoxifen*

PURPOSE: This study aimed to explore the functions and mechanisms of C-C motif chemokine receptor 6 (CCR6), a gene associated with progression and metastasis of colorectal cancer (CRC), in radiosensitivity of rectal cancer (RC). MATERIALS AND METHODS: RNA sequencing and immunohistochemical analysis on CCR6 expression were performed in pretreatment tissues of RC patients exhibiting different therapeutic effects of radiotherapy. Colonogenic survival assay was conducted in different CRC cell lines to assess their radiosensitivity. And the impact of CCR6 expression on radiosensitivity was validated through RNA interference. The DNA damage repair (DDR) abilities of cell lines with different CCR6 expression were evaluated through immunofluorescence-based γH2AX quantification. RESULTS: The CCR6 mRNA level was higher in patients without pathologic complete remission (pCR) than in those with pCR (fold changed, 2.11; p=0.004). High-level expression of CCR6 protein was more common in the bad responders than in the good responders (76.3% vs. 37.5%, p < 0.001). The CRC cell lines with higher CCR6 expression (LoVo and sw480) appeared to be more radioresistant, compared with the sw620 cell line which had lower CCR6 expression. CCR6 knockdown made the LoVo cells more sensitive to ionizing radiation (sensitization enhancement ratio, 1.738; p < 0.001), and decreased their DDR efficiency. CONCLUSION: CCR6 might affect the RC radiosensitivity through DDR process. These findings supported CCR6 as a predicting biomarker of radiosensitivity and a potential target of radiosensitization for RC patients.
Cell Line ; Colorectal Neoplasms ; DNA Damage ; Genes, vif ; Humans ; Neoplasm Metastasis ; Polymerase Chain Reaction ; Radiation Tolerance* ; Radiation, Ionizing ; Radiotherapy ; Rectal Neoplasms* ; RNA Interference ; RNA, Messenger ; Sequence Analysis, RNA ; Therapeutic Uses

BACKGROUND/AIMS: Peritoneal micrometastasis is known to play an important role in the recurrence of gastric cancer. However, its effects remain equivocal. Herein, we examine the messenger RNA (mRNA) as tumor markers, carcinoembryonic antigen (CEA), and cytokeratin 20 (CK20), in peritoneal washing fluid. Moreover, we evaluate whether these results could predict the recurrence of gastric cancer following curative resection. METHODS: We prospectively enrolled 132 patients with gastric cancers, who had received an operation, between January 2010 and January 2013. The peritoneal lavage fluid was collected at the operation field and semi-quantitative PCR was performed using the primers for CEA and CK20. We excluded patients with stage IA (n=28) early gastric cancer, positive cytologic examination of peritoneal washings (n=7), and those who were lost during follow up (n=18). RESULTS: A total of 79 patients with gastric cancers were enrolled, and the mean follow-up period was 39.95±19.25 months (range, 5-72 months). According to the multivariate analysis, T4 stage at the initial diagnosis was significantly associated with recurrence. All cases of recurrence were CEA positive and 6 cases were CK20 positive. The positive and negative predictive values of CEA were 32.0% and 100%, respectively, whereas those of CK20 were 37.5% and 71.4%, respectively. Disease free survival of CK20-negative cases was 36.17±20.28 months and that of CK20-positive cases was 32.06±22.95 months (p=0.39). CONCLUSIONS: It is unlikely that the real time polymerase chain reaction results of mRNA for CEA and CK20 in peritoneal washing fluid can predict recurrence. However, negative results can convince surgeons to perform curative R0 resection.
Biomarkers, Tumor ; Carcinoembryonic Antigen* ; Diagnosis ; Disease-Free Survival ; Follow-Up Studies ; Humans ; Keratin-20* ; Keratins* ; Multivariate Analysis ; Neoplasm Micrometastasis ; Peritoneal Lavage ; Polymerase Chain Reaction ; Prospective Studies ; Real-Time Polymerase Chain Reaction ; Recurrence ; RNA, Messenger* ; Stomach Neoplasms* ; Surgeons