LncRNA CTBP1-DT-encoded microprotein DDUP sustains DNA damage response signalling to trigger dual DNA repair mechanisms.

Sustaining DNA damage response (DDR) signalling via retention of DDR factors at damaged sites is important for transmitting damage-sensing and repair signals. Herein, we found that DNA damage provoked the association of ribosomes with IRES region in lncRNA CTBP1-DT, which overcame the negative effect of upstream open reading frames (uORFs), and elicited the novel microprotein DNA damage-upregulated protein (DDUP) translation via a cap-independent translation mechanism. Activated ATR kinase-mediated phosphorylation of DDUP induced a drastic 'dense-to-loose' conformational change, which sustained the RAD18/RAD51C and RAD18/PCNA complex at damaged sites and initiated RAD51C-mediated homologous recombination and PCNA-mediated post-replication repair mechanisms. Importantly, treatment with ATR inhibitor abolished the effect of DDUP on chromatin retention of RAD51C and PCNA, thereby leading to hypersensitivity of cancer cells to DNA-damaging chemotherapeutics. Taken together, our results uncover a plausible mechanism underlying the DDR sustaining and might represent an attractive therapeutic strategy in improvement of DNA damage-based anticancer therapies.

SRPK1/AKT axis promotes oxaliplatin-induced anti-apoptosis via NF-κB activation in colon cancer.

BACKGROUND: Colorectal cancer is the third most common diagnosis. Oxaliplatin is used as first-line treatment of colon cancer. However, oxaliplatin resistance greatly reduces its therapeutic effect. SRPK1 involves in pre-mRNA splicing and tumorigenesis. How SRPK1 mediates drug resistance in colon cancer is unknown. METHODS: The expression of SRPK1 was analyzed in the TCGA and the CPTAC pan-cancer samples and detected in colon cancer cell lines and tissues by IHC and western blot. The MTT and TUNEL assay were used to verify the anti-apoptosis ability of colon cancer cell. The activation of NF-κB was determined by luciferase assay and qRT-PCR. AKT, IKK, IκB and their phosphorylation level were verified by western blot. RESULTS: We found that SRPK1 expression was the second highest in TCGA and the CPTAC pan-cancer samples. The mRNA and protein levels of SRPK1 were increased in tissues from patients with colon cancer. SRPK1 was associated with clinical stage and TNM classifications in 148 cases of colon cancer patients. High SRPK1 levels correlated with poor prognosis (p < 0.001). SRPK1 overexpression enhanced the anti-apoptosis ability of colon cancer cells, whereas SRPK1 silencing had the opposite effect under oxaliplatin treatment. Mechanistically, SRPK1 enhances IKK kinase and IκB phosphorylation to promote NF-κB nuclear translocation to confer oxaliplatin resistance. CONCLUSIONS: Our findings suggest that SRPK1 participates in colon cancer progression and enhances the anti-apoptosis capacity to induce drug resistance in colon cancer cells via NF-κB pathway activation, and thus might be a potential pharmaceutically target for colon cancer treatment.

SOX9 drives the epithelial-mesenchymal transition in non-small-cell lung cancer through the Wnt/ß-catenin pathway.

BACKGROUND: The distant metastasis of cancer cells is a risk factor for tumor lethality and poor prognosis in non-small-cell lung carcinoma (NSCLC). Increased SOX9 expression has been associated with clinical stage and poor prognosis in NSCLC, but the molecular mechanisms by which SOX9 promotes metastasis in NSCLC are still unknown. METHODS: The relationship between SOX9 expression and T, N, M classification was assessed using the χ2 test and Spearman's analysis in 142 immunohistochemically diagnosed specimens of NSCLC. We also generated SOX9-overexpression and SOX9-knockdown cells lines and their corresponding control cell lines by transfection with lentiviral constructs. In vivo assay, SOX9-overexpressing and SOX9-knockdown NSCLC cells were injected in zebrafish to examine distance metastasis. Gene set enrichment analysis (GSEA) was applied to analysis the correlation between SOX9 overexpression and Wnt/ß-catenin pathway. Luciferase assay was used to check transcriptional activity of TCF/LEF and western blot and immunofluorescence was employed to detect ß-catenin translocation in SOX9-overexpression, SOX9-knockdown and their corresponding control cell lines. RESULTS: We found that SOX9 overexpression correlates with the T, N and M stage significantly (p = 0.03, 0.000, and 0.032 respectively) in 142 immunohistochemically diagnosed specimens of NSCLC. SOX9 overexpression was found to decrease the expression of the epithelial cell markers E-cadherin and γ-catenin and increase the expression of the mesenchymal cell markers N-cadherin and vimentin. An in vivo assay showed distant metastasis of the SOX9-overexpressing cells, which was not observed in the SOX9-knockdown cells. These findings indicate that SOX9 promotes distant metastasis by promoting EMT in NSCLC cells. GSEA showed that SOX9 overexpression was significantly correlated with the Wnt/ß-catenin pathway which was corroborated by the expression of EMT-associated proteins in this pathway and its downstream target genes. SOX9 overexpression was also found to enhance the transcriptional activity of TCF/LEF, promote the nuclear translocation of ß-catenin and increase the phosphorylation of GSK3ß at Ser9. Further, inhibition of ß-catenin suppressed the metastasis-promoting effects of SOX9 overexpression. CONCLUSIONS: This study is the first to report that SOX9 is associated with clinical TNM stage and indicates that SOX9 promotes migration, invasion and the EMT process through the Wnt/ß-catenin pathway.

SMARCD1 is a "Goldilocks" metastasis modifier.

Breast cancer is the most frequently diagnosed cancer worldwide, constituting around 15% of all diagnosed cancers in 2023. The predominant cause of breast cancer-related mortality is metastasis to distant essential organs, and a lack of metastasis-targeted therapies perpetuates dismal outcomes for late-stage patients. However, through our use of meiotic genetics to study inherited transcriptional network regulation, we have identified a new class of "Goldilocks" genes that are promising candidates for the development of metastasis-targeted therapeutics. Building upon previous work that implicated the CCR4-NOT RNA deadenylase complex in metastasis, we now demonstrate that the RNA-binding proteins (RNA-BPs) NANOS1, PUM2, and CPSF4 also regulate metastatic potential. Using cell lines, 3D culture, mouse models, and clinical data, we pinpoint Smarcd1 mRNA as a key target of all three RNA-BPs. Strikingly, both high and low expression of Smarcd1 is associated with positive clinical outcomes, while intermediate expression significantly reduces the probability of survival. Applying the theory of "essential genes" from evolution, we identify an additional 50 genes that span several cellular processes and must be maintained within a discrete window of expression for metastasis to occur. In the case of Smarcd1, small perturbations in its expression level significantly reduce metastasis in laboratory mouse models and alter splicing programs relevant to the ER+/HER2-enriched breast cancer subtype. The identification of subtype-specific "Goldilocks" metastasis modifier genes introduces a new class of genes and potential catalogue of novel targets that, when therapeutically "nudged" in either direction, may significantly improve late-stage patient outcomes.

Serine-arginine protein kinase 1 (SRPK1) promotes EGFR-TKI resistance by enhancing GSK3ß Ser9 autophosphorylation independent of its kinase activity in non-small-cell lung cancer.

Resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) is a major challenge for clinicians and patients with non-small cell lung cancer (NSCLC). Serine-arginine protein kinase 1 (SRPK1) is a key oncoprotein in the EGFR/AKT pathway that participates in tumorigenesis. We found that high SRPK1 expression was significantly associated with poor progression-free survival (PFS) in patients with advanced NSCLC undergoing gefitinib treatment. Both in vitro and in vivo assays suggested that SRPK1 reduced the ability of gefitinib to induce apoptosis in sensitive NSCLC cells independently of its kinase activity. Moreover, SRPK1 facilitated binding between LEF1, ß-catenin and the EGFR promoter region to increase EGFR expression and promote the accumulation and phosphorylation of membrane EGFR. Furthermore, we verified that the SRPK1 spacer domain bound to GSK3ß and enhanced its autophosphorylation at Ser9 to activate the Wnt pathway, thereby promoting the expression of Wnt target genes such as Bcl-X. The correlation between SRPK1 and EGFR expression was confirmed in patients. In brief, our research suggested that the SRPK1/GSK3ß axis promotes gefitinib resistance by activating the Wnt pathway and may serve as a potential therapeutic target for overcoming gefitinib resistance in NSCLC.

Golgi phosphoprotein 3 induces autophagy and epithelial-mesenchymal transition to promote metastasis in colon cancer.

In this study, we aimed to investigate whether and how Golgi phosphoprotein 3 (GOLPH3) facilitates colon cancer metastasis via the regulation of autophagy and epithelial-mesenchymal transition (EMT). The role GOLPH3 plays in colon cancer metastasis was analyzed using western blotting, immunohistochemistry, transwell, wound-healing, and zebrafish assays. Autophagy and EMT were assessed via RNA-sequencing (RNA-seq) analysis, mRFP-GFP-LC3 reporter assays, and their related markers. Significant associations were found between colon cancer clinical and pathological stages and poor prognosis. GOLPH3 facilitates colon cancer metastasis, both in vitro and in vivo. RNA-seq analysis of GOLPH3-overexpressing and control cell models revealed that GOLPH3 enhances EMT and autophagy. Moreover, examination of autophagic, epithelial, and mesenchymal markers in GOLPH3-overexpressing, -silenced, and control cell lines revealed that GOLPH3 promotes EMT and autophagy. When autophagy was inhibited, GOLPH3-promoted metastasis and EMT were counteracted in vitro and in vivo. Using RNA-seq, PI3K/Akt signaling was identified as the key downstream pathway on which GOLPH3 acts. Mechanistically, we demonstrated that GOLPH3 stimulates autophagy and induces EMT via the suppression of the phosphorylation of protein kinase B (Akt) at Ser473. In summary, GOLPH3 induces autophagy and EMT, promoting metastasis in colon cancer. Beyond this, and in contrast to conventional perspectives, we discovered that GOLPH3 represses the phosphorylation of Akt at Ser473.

Oncoprotein Bmi-1 renders apoptotic resistance to glioma cells through activation of the IKK-nuclear factor-kappaB Pathway.

One of the features of malignant gliomas is their deviant resistance to cellular apoptosis induced by cytotoxic reagents. Bmi-1, an oncoprotein, has been linked to oncogenesis and cancer progression in various types of human cancers including gliomas. However, the mechanisms underlying Bmi-1 antiapoptotic function remain largely unknown. In this study, we report that Bmi-1 renders apoptotic resistance to glioma cells through nuclear factor-kappaB (NF-kappaB). In glioma cells, ectopic expression of Bmi-1 significantly inhibits doxorubicin-, BCNU-, or UV irradiation- induced apoptosis through reduction of activated caspase-3 and PARP, and induction of Bcl-X(L). Cellular depletion of Bmi-1 enhances the sensitivity of glioma cells to apoptosis induced by doxorubicin, BCNU, or UV irradiation. Bmi-1 activates NF-kappaB through stimulation of IkappaB phosphorylation, nuclear translocation, and transcriptional activity of NF-kappaB and expression of downstream genes of NF-kappaB including caspase-3, PARP, Bcl-X(L), and c-Myc. Inhibition of the IKK-NF-kappaB pathway abrogates the antiapoptotic effect of Bmi-1 on glioma cells. In high-grade gliomas, Bmi-1 and NF-kappaB are co-expressed in the cell nucleus. Up-regulation of Bmi-1 also correlates with tumor progression and poor survival of patients with gliomas. Together, our data demonstrate that Bmi-1 bestows apoptotic resistance to glioma cells through the IKK-NF-kappaB pathway and suggest Bmi-1 as a useful indicator for glioma prognosis.

GOLPH3/CKAP4 promotes metastasis and tumorigenicity by enhancing the secretion of exosomal WNT3A in non-small-cell lung cancer.

Cancer metastasis is the main cause of mortality associated with non-small-cell lung cancer (NSCLC), accounting for up to 70% of deaths among patients. The mechanisms underlying distal metastasis remain largely unknown. Golgi phosphoprotein 3 (GOLPH3) correlates negatively with overall survival in multiple tumors. In this study, we evaluated the function of GOLPH3 in NSCLC distal metastasis. GOLPH3 was expressed at high levels in samples from patients with NSCLC and was positively associated with clinicopathologic characteristics including clinical stage (P < 0.001), T (P = 0.001), N (P = 0.007), and M (P = 0.001) classification. Functionally, Transwell and wound-healing assays suggested that GOLPH3 overexpression enhances NSCLC cell migration and invasion abilities. Tumor-sphere formation and flow cytometry assays demonstrated that GOLPH3 overexpression enhances a stem cell-like phenotype of NSCLC cells. Metastasis models established by tail vein and intracardiac injection confirmed the pro-metastatic function of GOLPH3 in vivo. A subcutaneous tumor formation model confirmed that GOLPH3 overexpression increased the tumorigenicity of NSCLC cells. Mechanistically, gene set enrichment analysis revealed a positive association of GOLPH3 mRNA expression with WNT-activated gene signatures. Luciferase-reporter and nuclear extract assays showed that GOLPH3 overexpression enhances metastasis and tumorigenicity through activation of the WNT/ß-catenin pathway. Immunoprecipitation-mass spectrometry and gene ontology analysis demonstrated that GOLPH3 interacts with cytoskeleton-associated protein 4 (CKAP4) in exosome-mediated distal metastasis. We found that GOLPH3 decreased the amount of plasma membrane-localized CKAP4 and increased the amount of exosome-localized CKAP4 to promote the formation of CKAP4-containing exosomes. Furthermore, we demonstrated that CKAP4 binds exosomal WNT3A to enhance its secretion. Therefore, the GOLPH3/CKAP4 axis plays a crucial role in promoting exosomal-WNT3A secretion to enhance and maintain the stem-like phenotype and metastasis in NSCLC, thus indicating the therapeutic potential of GOLPH3 in patients with NSCLC metastasis.

Clinical significance of sphingosine kinase-1 expression in human astrocytomas progression and overall patient survival.

PURPOSE: To characterize the expression of sphingosine kinase-1 (SPHK1) in human astrocytomas and to investigate the association between SPHK1 expression and progression of astrocytomas. EXPERIMENTAL DESIGN: The expression of SPHK1 in normal human astrocytes, astrocytoma cell lines, and four pairs of matched astrocytoma tissues and their adjacent normal brain tissues were detected by quantitative reverse transcription-PCR and Western blot. In addition, SPHK1 protein expression was examined in 243 cases of histologically characterized astrocytomas by immunohistochemistry. Statistical analyses were applied to test for prognostic and diagnostic associations. RESULTS: SPHK1 in astrocytoma cell lines was elevated at both mRNA and protein levels, and the SPHK1 mRNA and protein were significantly up-regulated by up to 6.8- and 40-fold, respectively, in primary astrocytomas compared with those in the adjacent noncancerous brain tissues. Immunohistochemical analysis showed that 100 of 243 (41.2%) paraffin-embedded archival astrocytoma biopsies exhibited high expression of SPHK1. Statistical analysis suggested that the up-regulation of SPHK1 was significantly correlated with the histologic grade of astrocytoma (P=0.000) and that patients with high SPHK1 level exhibited shorter survival time (P<0.001). Multivariate analysis revealed that SPHK1 up-regulation might be an independent prognostic indicator for the survival of patients with astrocytoma. CONCLUSIONS: SPHK1 might represent a novel and useful prognostic marker for astrocytoma and play a role during the development and progression of the disease.

Astrocyte elevated gene-1 is a novel prognostic marker for breast cancer progression and overall patient survival.

PURPOSE: The present study was aimed at clarifying the expression of astrocyte elevated gene-1 (AEG-1), one of the target genes of oncogenic Ha-ras, in breast cancer and its correlation with clinicopathologic features, including the survival of patients with breast cancer. EXPERIMENTAL DESIGN: The expression of AEG-1 in normal breast epithelial cells, breast cancer cell lines, and in four cases of paired primary breast tumor and normal breast tissue was examined using reverse transcription-PCR and Western blot. Real-time reverse transcription-PCR was applied to determine the mRNA level of AEG-1 in the four paired tissues, each from the same subject. Furthermore, AEG-1 protein expression was analyzed in 225 clinicopathologically characterized breast cancer cases using immunohistochemistry. Statistical analyses were applied to test for the prognostic and diagnostic associations. RESULTS: Western blot and reverse transcription-PCR showed that the expression level of AEG-1 was markedly higher in breast cancer cell lines than that in the normal breast epithelial cells at both mRNA and protein levels. AEG-1 expression levels were significantly up-regulated by up to 35-fold in primary breast tumors in comparison to the paired normal breast tissue from the same patient. Immunohistochemical analysis revealed high expression of AEG-1 in 100 of 225 (44.4%) paraffin-embedded archival breast cancer biopsies. Statistical analysis showed a significant correlation of AEG-1 expression with the clinical staging of the patients with breast cancer (P = 0.001), as well as with the tumor classification (P = 0.004), node classification (P = 0.026), and metastasis classification (P = 0.001). Patients with higher AEG-1 expression had shorter overall survival time, whereas patients with lower AEG-1 expression had better survival. Multivariate analysis suggested that AEG-1 expression might be an independent prognostic indicator for the survival of patients with breast cancer. CONCLUSIONS: Our results suggest that AEG-1 protein is a valuable marker of breast cancer progression. High AEG-1 expression is associated with poor overall survival in patients with breast cancer.

[Study of a serum protein fingerprint diagnostic model in patients with hypertensive disorder complicating pregnancy].

OBJECTIVE: To analyze the alterations of serum protein fingerprint in patients with hypertensive disorder complicating pregnancy (HDCP), screen serum biomarker and establish a diagnostic model of HDCP. METHODS: Surface-enhanced laser desorption lionization-time of flight-mass spectrometry (SELDI-TOF-MS) technology was used to analyze serum including 25 cases of HDCP patients and 30 cases of age-, gravity- and parity-matched healthy term pregnant women on IMAC3-Cu proteinchip before delivery. Biomarker Wizard and Biomarker Pattern software was used to detect protein peaks significantly different between HDCP and controls, and establish a primary diagnostic model of HDCP. This model was further evaluated by blind test using other 16 parts of serum protein fingerprint. RESULT: Ten protein peaks were significantly different at the molecular range of 2000-50000 (P < 0.01). A diagnostic model consisting of 5 protein peaks(39 837,6196,15 529, 43 248 and 22 292) was established with 100% (25/25) sensitivity, 90% (27/30) specificity, 89% (25/28) positive predictive value and 100% (27/27) negative predictive value. Blind test generated a sensitivity of 75% and specificity of 75% respectively. CONCLUSION: Many differential expressed proteins exist in serum of patients with HDCP. The diagnostic model consisting of 5 protein peaks has relative high sensitivity and specificity, and can discriminate HDCP from healthy pregnant

Serine-arginine protein kinase 1 is associated with breast cancer progression and poor patient survival.

Breast cancer is the most common cancer and the second leading cause of mortality for women worldwide. It is necessary to identify valuable molecular markers to predict breast cancer progression in patients and treatment effect. Serine-arginine protein kinase 1 (SRPK1), a member of SR kinase family, phosphorylates the SR splicing factors which plays essential roles in normal cell development and multiple human diseases. In the current study, we wanted to explore if there are any relationships between SRPK1 expression in breast cancer and its clinical characteristics. The results showed that SRPK1 is upregulated in breast cancer cell lines and tissues at both mRNA and protein levels, measured by quantitative reverse transcriptase PCR and Western blotting. Immunohistochemical analysis showed a high expression of SRPK1 in 132 paraffin samples of patients with breast cancer; statistical analyses demonstrated that high expression of SRPK1 significantly correlated with clinical staging of patients with breast cancer (P < 0.001), TNM classification (P < 0.05). Low expression of SRPK1 leads to longer survival time, while high expression of SRPK1 leads to shorter survival time of patients. Multivariate analysis revealed that upregulation of SRPK1 might be an independent prognostic marker for the outcomes of patients with breast cancer. In conclusion, upregulation of SRPK1 might play an important role in the progression of breast cancer and might be considered as the potential diagnostic and therapeutic target to this malignancy.

Clinical significance of SOX9 in human non-small cell lung cancer progression and overall patient survival.

BACKGROUND: Sex determining region Y (SRY)-related high mobility groupbox 9 (SOX9) is an important transcription factor required for development, which regulates the expression of target genes in the associated pathway. The aim of this study was to describe the expression of SOX9 in human non-small cell lung cancer (NSCLC) and to investigate the association between SOX9 expression and progression of NSCLC. METHODS: SOX9 protein and mRNA expression in normal human pneumonocytes, lung cancer cell lines, and eight pairs of matched lung cancer tissues and their adjacent normal lung tissues were detected by Western blotting and real-time reverse transcription-polymerase chain reaction (RT-PCR). Immunohistochemistry was used to determine SOX9 protein expression in 142 cases of histologically characterized NSCLC. Statistical analyses were applied to test for prognostic and diagnostic associations. RESULTS: SOX9 in lung cancer cell lines was upregulated at both mRNA and protein levels, and SOX9 mRNA and protein were also elevated in NSCLC tissues compared with levels in corresponding adjacent non-cancerous lung tissues. Immunohistochemical analysis demonstrated a high expression of SOX9 in 74/142 (52.1%) paraffin-embedded archival lung cancer biopsies. Statistical analysis indicated that upregulation of SOX9 was significantly correlated with the histological stage of NSCLC (P=0.017) and that patients with a high SOX9 level exhibited a shorter survival time (P<0.001). Multivariate analysis illustrated that SOX9 upregulation might be an independent prognostic indicator for the survival of patients with NSCLC. CONCLUSIONS: This work shows that SOX9 may serve as a novel and prognostic marker for NSCLC, and play a role during the development and progression of the disease.