Upregulated lncRNA PRNT promotes progression and oxaliplatin resistance of colorectal cancer cells by regulating HIPK2 transcription.

BACKGROUND: Colorectal cancer (CRC) is the third most common cancer and a significant cause of cancer-related mortality globally. Resistance to chemotherapy, especially during CRC treatment, leads to reduced effectiveness of drugs and poor patient outcomes. Long noncoding RNAs (lncRNAs) have been implicated in various pathophysiological processes of tumor cells, including chemotherapy resistance, yet the roles of many lncRNAs in CRC remain unclear. AIM: To identify and analyze the lncRNAs involved in oxaliplatin resistance in CRC and to understand the underlying molecular mechanisms influencing this resistance. METHODS: Gene Expression Omnibus datasets GSE42387 and GSE30011 were reanalyzed to identify lncRNAs and mRNAs associated with oxaliplatin resistance. Various bioinformatics tools were employed to elucidate molecular mechanisms. The expression levels of lncRNAs and mRNAs were assessed via quantitative reverse transcription-polymerase chain reaction. Functional assays, including MTT, wound healing, and Transwell, were conducted to investigate the functional implications of lncRNA alterations. Interactions between lncRNAs and transcription factors were examined using RIP and luciferase reporter assays, while Western blotting was used to confirm downstream pathways. Additionally, a xenograft mouse model was utilized to study the in vivo effects of lncRNAs on chemotherapy resistance. RESULTS: LncRNA prion protein testis specific (PRNT) was found to be upregulated in oxaliplatin-resistant CRC cell lines and negatively correlated with homeodomain interacting protein kinase 2 (HIPK2) expression. PRNT was demonstrated to sponge transcription factor zinc finger protein 184 (ZNF184), which in turn could regulate HIPK2 expression. Altered expression of PRNT influenced CRC cell sensitivity to oxaliplatin, with overexpression leading to decreased sensitivity and decreased expression reducing resistance. Both RIP and luciferase reporter assays indicated that ZNF184 and HIPK2 are targets of PRNT. The PRNT/ZNF184/HIPK2 axis was implicated in promoting CRC progression and oxaliplatin resistance both in vitro and in vivo. CONCLUSION: The study concludes that PRNT is upregulated in oxaliplatin-resistant CRC cells and modulates the expression of HIPK2 by sponging ZNF184. This regulatory mechanism enhances CRC progression and resistance to oxaliplatin, positioning PRNT as a promising therapeutic target for CRC patients undergoing oxaliplatin-based chemotherapy.

High expression of autophagy-related gene EIF4EBP1 could promote tamoxifen resistance and predict poor prognosis in breast cancer.

BACKGROUND: Breast cancer (BC) remains a public health problem. Tamoxifen (TAM) resistance has caused great difficulties for treatment of BC patients. Eukaryotic translation initiation factor 4E binding protein 1 (EIF4EBP1) plays critical roles in the tumorigenesis and progression of BC. However, the expression and mechanism of EIF4EBP1 in determining the efficacy of TAM therapy in BC patients are still unclear. AIM: To investigate the expression and functions of EIF4EBP1 in determining the efficacy of TAM therapy in BC patients. METHODS: High-throughput sequencing data of breast tumors were downloaded from the Gene Expression Omnibus database. Differential gene expression analysis identified EIF4EBP1 to be significantly upregulated in cancer tissues. Its prognostic value was analyzed. The biological function and related pathways of EIF4EBP1 was analyzed. Subsequently, the expression of EIF4EBP1 was determined by real-time reverse transcription polymerase chain reaction and western blotting. Cell Counting Kit-8 assays, colony formation assay and wound healing assay were used to understand the phenotypes of function of EIF4EBP1. RESULTS: EIF4EBP1 was upregulated in the TAM-resistant cells, and EIF4EBP1 was related to the prognosis of BC patients. Gene Set Enrichment Analysis showed that EIF4EBP1 might be involved in Hedgehog signaling pathways. Decreasing the expression of EIF4EBP1 could reverse TAM resistance, whereas overexpression of EIF4EBP1 promoted TAM resistance. CONCLUSION: This study indicated that EIF4EBP1 was overexpressed in the BC and TAM-resistant cell line, which increased cell proliferation, invasion, migration and TAM resistance in BC cells.

An Analysis of Clinical and Pathologic Features, RecurIndex Genomic Profiles, and Survival Outcomes in HER2-Low Breast Cancer.

BACKGROUND: In recent years, breast cancer has become the most common cancer in the world, increasing women's health risks. Approximately 60% of breast cancers are categorized as human epidermal growth factor receptor 2 (HER2)-low tumors. Recently, antibody-drug conjugates have been found to have positive anticancer efficacy in patients with HER2-low breast cancer, but more studies are required to comprehend their clinical and molecular characteristics. METHODS: In this study, we retrospectively analyzed the data of 165 early breast cancer patients with pT1-2N1M0 who had undergone the RecurIndex testing. To better understand HER2-low tumors, we investigated the RecurIndex genomic profiles, clinicopathologic features, and survival outcomes of breast cancers according to HER2 status. RESULTS: First, there were significantly more hormone receptor (HR)-positive tumors, luminal-type tumors, and low Ki67 levels in the HER2-low than in the HER2-zero. Second, RI-LR (P = .0294) and RI-DR (P = .001) scores for HER2-low and HER2-zero were statistically significant. Third, within HER2-negative disease, HR-positive/HER2-low tumors showed highest ESR1, NFATC2IP, PTI1, ERBB2, and OBSL1 expressions. Fourth, results of the survival analysis showed that lower expression of HER2 was associated with improved relapse-free survival for HR-positive tumors, but not for HR-negative tumors. CONCLUSIONS: The present study highlights the unique features of HER2-low tumors in terms of their clinical characteristics as well as their gene expression profiles. HR status may influence the prognosis of patients with HER2-low expression, and patients with HR-positive/HER2-low expression may have a favorable outcome.

Metformin improves the outcomes in Chinese invasive breast cancer patients with type 2 diabetes mellitus.

Early reports indicate that metformin, a clinical drug administered to treat type 2 diabetes mellitus (T2DM), was found to be associated with a better prognosis of cancer. The objective of this study was retrospectively analyzed the effect of metformin on the outcomes of Chinese breast cancer patients with T2DM. A total of 3757 primary invasive breast cancer patients who underwent surgery from January 2010 to December 2013 were enrolled. According to the medication treatment, all the patients were divided as non-diabetes group, metformin group and insulin group. The follow-up data for disease-free survival (DFS) and overall survival (OS) were obtained from 3553 patients (median follow up of 85 months) and estimated with the Kaplan-Meier method followed by a log-rank test. Multivariate Cox proportional hazards regression model was applied. The results showed that there was a significant survival difference among non-diabetes group, metformin group and insulin group, 5-year DFS was 85.8%, 96.1%, 73.0%, and 5-year OS was 87.3%, 97.1%, 73.3% respectively (P < 0.05). Prognostic analysis showed metformin was significantly associated with better DFS and OS. Our results suggested that metformin may have a good effect on the survival of invasive breast cancer patients with T2DM.

Pegylated liposomal doxorubicin plus cyclophosphamide followed by docetaxel as neoadjuvant chemotherapy in locally advanced breast cancer (registration number: ChiCTR1900023052).

Anthracyclines have a profound effect on breast cancer. However, at higher dosages, there are many toxic side effects associated with their use; these include bone marrow suppression, alopecia, gastrointestinal reactions and cardiotoxicity. Pegylated liposomal doxorubicin (PEG-LG) has been demonstrated to achieve equivalent efficacy to conventional doxorubicin, with significantly lower cardiotoxicity. We conducted an open-label, multicenter, single-armed clinical trial useing an NAC regimen based on four cycles of PEG-LD 40 mg/m2 plus cyclophosphamide (CPM) 600 mg/m2 on day 1 of a 21 day schedule, followed by four cycles of docetaxel (DTX) 85 mg/m2 on day 1 of a 21 day schedule. The primary endpoint analysed was the pathological complete response rate (pCR) in the breast, while treatment toxicities and safety were also assessed. The results showed that the breast pCR rate was 18.75% (95% CI 11.5-26.0%). Among the different molecular cancer types, the triple negative breast cancer patients had the highest pCR, at 43.75%. No significant decrease in left ventricular ejection fraction was observed. Our data tends to draw the conclusion that this regimen is a viable option for the neoadjuvant treatment of patients with LABC, especially in the triple-negative subtype and patients with heart abnormalities. We believe the efficacy and the safety of this regimen is likely to be the same based on published data from other studies but that this cannot be certain without a randomized trial.

Body Mass Index at Diagnosis as a Prognostic Factor for Early-Stage Invasive Breast Cancer after Surgical Resection.

BACKGROUND: The aim of this study was to investigate the association between body mass index (BMI) and prognosis of Chinese women with breast cancer. PATIENTS AND METHODS: 3,380 primary breast cancer patients who underwent surgery from 2010 to 2012 were selected and classified as low BMI group (BMI < 25.0) and high BMI group (BMI ≥ 25.0). The follow-up data for disease-free survival (DFS) and overall survival (OS) were obtained from 3,178 patients (median follow-up of 58 months). Cox regression analysis was used to evaluate the effect of BMI on DFS and OS. RESULTS: The high BMI group showed more aggressive pathological features. BMI was negatively associated with OS (hazard ratio (HR) 1.33, 95% confidence interval (CI) 1.06-1.66; p = 0.012) but not DFS (HR 1.15, 95% CI 0.94-1.40; p = 0.17). Furthermore, when stratified by age, BMI was significantly and negatively associated with OS (HR 1.43, 95% CI 1.05-1.95; p = 0.025) in patients above 50 years of age, but this effect was not detected in younger patients. CONCLUSION: BMI was an independent prognostic factor of OS in Chinese women with breast cancer, and age might be a mitigating factor. Among patients above 50 years of age, those with a high BMI were at greater risk of poor prognosis compared to individuals with a low BMI.

Impact of next-generation sequencing (NGS) for primary endocrine resistance in breast cancer patients.

Multiple mechanisms have been detected to account for the acquired resistance to endocrine therapies in breast cancer. In this study we retrospectively studied the mechanism of primary endocrine resistance in estrogen receptor positive (ER+) breast cancer patients by next-generation sequencing (NGS). Tumor specimens and matched blood samples were obtained from 24 ER+ breast cancer patients. Fifteen of them displayed endocrine resistance, including recurrence and/or metastases within 24 months from the beginning of endocrine therapy, and 9 patients remained sensitive to endocrine therapy for more than 5 years. Genomic DNA of tumor tissue was extracted from formalin-fixed paraffin-embedded (FFPE) tumor tissue blocks. Genomic DNA of normal tissue was extracted from peripheral blood mononuclear cells (PBMC). Sequencing libraries for each sample were prepared, followed by target capturing for 372 genes that are frequently rearranged in cancers. Massive parallel sequencing was then performed using Illumina NextSeq 500, and samples with a mean sequencing depth of 500× were analyzed. The analysis revealed that 8 (55%) of 15 patients showed phosphatidylinositol 3-kinase CA (PIK3CA) mutations, including 3 pathogenic variants in kinase domain, 3 pathogenic variants in helical domain, and 2 variants of unknown significance, in the endocrine-resistant group, while 3 (33%) of 9 patients displayed PIK3CA mutations, including 2 pathogenic variants in kinase domain and 1 pathogenic variant in helical domain, in the endocrine-sensitive group. In the endocrine-sensitive group, copy number gain of C11orf30 (EMSY) gene, copy number loss of CDH1 (E-cadherin) gene, and a missense mutation of splicing factor 3b (SF3B1) gene were also detected, which would probably decrease the expression of ESR1 and contribute to endocrine sensitivity. Collectively, the PIK3CA mutation rate in the resistance group is relatively higher than that in the sensitive group and thus PIK3CA mutations may contribute the primary endocrine resistance of breast cancer.

The expression and biological function of the PHF2 gene in breast cancer.

PHD Finger Protein 2 (PHF2), as a protein code and a transcription regulatory gene, is a member of the Jumonji-C domain (JmjC). PHF2 is located at human chromosome 9q22.31 and is frequently decreased in various malignancies. However, the definite role of PHF2 in breast cancer remains unclear. To detect the expression and function of PHF2 in breast cancer, a q-PCR assay was used to detect the mRNA expression of PHF2 in breast cancer cell lines and paired breast cancer tissues, and immunohistochemistry was used to test the protein expression in breast cancer tissues and adjacent tissues. In addition, an adenovirus vector system was utilized to upregulate the expression of PHF2 in breast cancer cells. In our study, we found that PHF2 was down-expressed in breast cancer on both the mRNA and protein levels and the low expression of PHF2 was significantly associated with lymph node metastasis, Ki67 positive rate, ER negative expression and poor prognosis in breast cancer patients. The ectopic expression of PHF2 obviously inhibited the proliferation of breast cancer cell lines and the growth of xenograft tumors. Due to the tumor suppressor signature of PHF2 in breast cancer, we have reasons to believe that it could be a promoting marker and target for the prognosis and therapy of breast cancer.

Epigenetic silencing of ADAMTS18 promotes cell migration and invasion of breast cancer through AKT and NF-κB signaling.

ADAMTS18 dysregulation plays an important role in many disease processes including cancer. We previously found ADAMTS18 as frequently methylated tumor suppressor gene (TSG) for multiple carcinomas, however, its biological functions and underlying molecular mechanisms in breast carcinogenesis remain unknown. Here, we found that ADAMTS18 was silenced or downregulated in breast cancer cell lines. ADAMTS18 was reduced in primary breast tumor tissues as compared with their adjacent noncancer tissues. ADAMTS18 promoter methylation was detected in 70.8% of tumor tissues by methylation-specific PCR, but none of the normal tissues. Demethylation treatment restored ADAMTS18 expression in silenced breast cell lines. Ectopic expression of ADAMTS18 in breast tumor cells resulted in inhibition of cell migration and invasion. Nude mouse model further confirmed that ADAMTS18 suppressed breast cancer metastasis in vivo. Further mechanistic studies showed that ADAMTS18 suppressed epithelial-mesenchymal transition (EMT), further inhibited migration and invasion of breast cancer cells. ADAMT18 deregulated AKT and NF-κB signaling, through inhibiting phosphorylation levels of AKT and p65. Thus, ADAMTS18 as an antimetastatic tumor suppressor antagonizes AKT and NF-κB signaling in breast tumorigenesis. Its methylation could be a potential tumor biomarker for breast cancer.

Dickkopf-related protein 2 induces G0/G1 arrest and apoptosis through suppressing Wnt/ß-catenin signaling and is frequently methylated in breast cancer.

Dickkopf-related protein 2 (DKK2) is one of the antagonists of Wnt/ß-catenin signaling, with its downregulation reported in multiple cancers. However, how DKK2 contributes to breast tumorigenesis remains unclear. We examined its expression and promoter methylation in 10 breast tumor cell lines, 98 primary tumors, and 21 normal breast tissues. Compared with normal tissues, DKK2 was frequently silenced in breast cell lines (7/8). DKK2 promoter methylation was detected in 77.8% of cell lines and 86.7% of breast tumors; while rarely detected in normal breast tissues (19%), indicating common DKK2 methylation in breast cancer. Ectopic expression of DKK2 changed breast tumor cell morphology, inhibited cell proliferation and colony formation by inducing G0/G1 cell cycle arrest and apoptosis, and suppressed tumor cell migration by reversing epithelial-mesenchymal transition (EMT) and downregulating stem cell markers. Moreover, restored expression of DKK2 in MCF7 cells disrupted the microtube formation of human umbilical vein endothelial cells on Matrigel®. In vivo, the growth of MDA-MB-231 cells in nude mice was markedly decreased after stable expression of DKK2. DKK2 suppressed canonical Wnt/ß-catenin signaling by inhibiting ß-catenin activity with decreased active ß-catenin protein. Thus, our findings demonstrate that DKK2 functions as a tumor suppressor through inhibiting cell proliferation and inducing apoptosis via regulating Wnt signaling during breast tumorigenesis.

Cyclooxygenase-2 in tumor-associated macrophages promotes metastatic potential of breast cancer cells through Akt pathway.

Tumor-associated macrophages (TAMs) promote cancer development and progression by releasing various cytokines and chemokines. Previously, we have found that the number of COX-2+ TAMs was associated with lymph node metastasis in breast cancer. However, the mechanism remains enigmatic. In this study, we show that COX-2 in breast TAMs enhances the metastatic potential of breast cancer cells. COX-2 in TAMs induces MMP-9 expression and promotes epithelial-mesenchymal transition (EMT) in breast cancer cells. In addition, COX-2/PGE2 induces IL-6 release in macrophages. Furthermore, we find that the activation of Akt pathway in cancer cells is crucial for the pro-metastatic effect of COX-2+ TAMs by regulating MMP-9 and EMT. These findings indicate that TAMs facilitate breast cancer cell metastasis through COX-2-mediated intercellular communication.

Epigenetic identification of ZNF545 as a functional tumor suppressor in multiple myeloma via activation of p53 signaling pathway.

The KRAB-zinc-finger protein ZNF545 was recently identified as a potential suppressor gene in several tumors. However, the regulatory mechanisms of ZNF545 in tumorigenesis remain unclear. In this study, we investigated the expression and roles of ZNF545 in multiple myeloma (MM). ZNF545 was frequently downregulated in MM tissues compared with non-tumor bone marrow tissues. ZNF545 expression was silenced by promoter methylation in MM cell lines, and could be restored by demethylation treatment. ZNF545 methylation was detected in 28.3% of MM tissues, compared with 4.3% of normal bone marrow tissues. ZNF545 transcriptionally activated the p53 signaling pathway but had no effect on Akt in MM, whereas ectopic expression of ZNF545 in silenced cells suppressed their proliferation and induced apoptosis. We therefore identified ZNF545 as a novel tumor suppressor inhibiting tumor growth through activation of the p53 pathway in MM. Moreover, tumor-specific methylation of ZNF545 may represent an epigenetic biomarker for MM diagnosis, and a potential target for specific therapy.

Paired box 5 is a frequently methylated lung cancer tumour suppressor gene interfering ß-catenin signalling and GADD45G expression.

Recent studies suggest that paired box 5 (PAX5) is down-regulated in multiple tumours through its promoter methylation. However, the role of PAX5 in non-small cell lung cancer (NSCLC) pathogenesis remains unclear. The aim of this study is to examine PAX5 expression, its methylation status, biological functions and related molecular mechanism in NSCLC. We found that PAX5 was widely expressed in normal adult tissues but silenced or down-regulated in 88% (7/8) of NSCLC cell lines. PAX5 expression level was significantly lower in NSCLC than that in adjacent non-cancerous tissues (P = 0.0201). PAX5 down-regulation was closely associated with its promoter hypermethylation status and PAX5 expression could be restored by demethylation treatment. Frequent PAX5 promoter methylation in primary tumours (70%) was correlated with lung tumour histological types (P = 0.006). Ectopic expression of PAX5 in silenced lung cancer cell lines (A549 and H1975) inhibited their colony formation and cell viability, arrested cell cycle at G2 phase and suppressed cell migration/invasion as well as tumorigenicity in nude mice. Restoration of PAX5 expression resulted in the down-regulation of ß-catenin and up-regulation of tissue inhibitors of metalloproteinase 2, GADD45G in lung tumour cells. In summary, PAX5 was found to be an epigenetically inactivated tumour suppressor that inhibits NSCLC cell proliferation and metastasis, through down-regulating the ß-catenin pathway and up-regulating GADD45G expression.

Epigenetic upregulation of PSD-95 contributes to the rewarding behavior by morphine conditioning.

Abuse of opiates, including morphine, induced remarkable synaptic adaptation in several brain regions including ventral tegmental area (VTA), which underlay the induction and maintenance of opioid dependence and addiction. Scaffolding protein postsynaptic density protein 95 (PSD-95) is critically involved in the glutamatergic synaptic maturation and plasticity in the central neurons. The present study revealed a significantly increased mRNA and protein expression of PSD-95 in the VTA of the rats conditioned with morphine. The further chromatin immunoprecipitation study found an increased histone H3 acetylation in the promoter region of Dlg4. An upregulation of expression of phosphorylated cAMP response element-binding protein (pCREB) and the occupancy of pCREB in the Dlg4 promoter region were shown in the VTA of the morphine-conditioned rats. Inhibition of pCREB activity significantly decreased the histone H3 acetylation in Dlg4 promoter region, PSD-95 upregulation, enhancement of glutamatergic strength and the preference to morphine-paired chamber in the rats with morphine conditioning. These results suggested that CREB-mediated epigenetic upregulation of PSD-95 critically contributed to the enhanced glutamatergic transmission and rewarding behavior induced by morphine conditioning.