Chemotherapy-driven increases in the CDKN1A/PTN/PTPRZ1 axis promote chemoresistance by activating the NF-κB pathway in breast cancer cells

BACKGROUND

Chemotherapy is the primary established systemic treatment for patients with breast cancer, especially those with the triple-negative subtype. Simultaneously, the resistance of triple-negative breast cancer (TNBC) to chemotherapy remains a major clinical problem. Our previous study demonstrated that the expression levels of PTN and its receptor PTPRZ1 were upregulated in recurrent TNBC tissue after chemotherapy, and this increase was closely related to poor prognosis in those patients. However, the mechanism and function of chemotherapy-driven increases in PTN/PTPRZ1 expression are still unclear.

METHODS

We compared the expression of PTN and PTPRZ1 between normal breast and cancer tissues as well as before and after chemotherapy in cancer tissue using the microarray analysis data from the GEPIA database and GEO database. The role of chemotherapy-driven increases in PTN/PTPRZ1 expression was examined with a CCK-8 assay, colony formation efficiency assay and apoptosis analysis with TNBC cells. The potential upstream pathways involved in the chemotherapy-driven increases in PTN/PTPRZ1 expression in TNBC cells were explored using microarray analysis, and the downstream mechanism was dissected with siRNA.

RESULTS

We demonstrated that the expression of PTN and PTPRZ1 was upregulated by chemotherapy, and this change in expression decreased chemosensitivity by promoting tumour proliferation and inhibiting apoptosis. CDKN1A was the critical switch that regulated the expression of PTN/PTPRZ1 in TNBC cells receiving chemotherapy. We further demonstrated that the mechanism of chemoresistance by chemotherapy-driven increases in the CDKN1A/PTN/PTPRZ1 axis depended on the NF-κB pathway.

CONCLUSIONS

Our studies indicated that chemotherapy-driven increases in the CDKN1A/PTN/PTPRZ1 axis play a critical role in chemoresistance, which suggests a novel strategy to enhance chemosensitivity in breast cancer cells, especially in those of the triple-negative subtype.

The regulatory roles of lncRNAs in the process of breast cancer invasion and metastasis

Breast cancer (BC) is the most common cancer and principal cause of death among females worldwide. Invasion and metastasis are major causes which influence the survival and prognosis of BC. Therefore, to understand the molecule mechanism underlying invasion and metastasis is paramount for developing strategies to improve survival and prognosis in BC patients. Recent studies have reported that long non-coding RNAs (lncRNAs) play critical roles in the regulation of BC invasion and metastasis through a variety of molecule mechanisms that endow cells with an aggressive phenotype. In this article, we focused on the function of lncRNAs on BC invasion and metastasis through participating in epithelial-to-mesenchymal transition, strengthening cancer stem cells generation, serving as competing endogenous lncRNAs, influencing multiple signaling pathways as well as regulating expressions of invasion-metastasis related factors, including cells adhesion molecules, extracellular matrix, and matrix metallo-proteinases. The published work described has provided a better understanding of the mechanisms underpinning the contribution of lncRNAs to BC invasion and metastasis, which may lay the foundation for the development of new strategies to prevent BC invasion and metastasis.

Long non-coding RNA TP73-AS1 sponges miR-194 to promote colorectal cancer cell proliferation, migration and invasion via up-regulating TGFα

OBJECTIVE

Colorectal cancer (CRC) is the 3rd most common cancer worldwide. Recently, long non-coding RNAs (lncRNAs) were found to be critical modulators in the CRC progression. The aim of this study is to investigate the potential roles of lncRNA P73 antisense RNA 1T (TP73-AS1) in CRC development and progression.

METHODS

Quantitative real-time PCR (qRT-PCR) was performed to determine relevant gene expression levels; western blot was performed to determine protein expression levels; CCK-8, colony formation, wound healing and Transwell invasion assays were used to determined CRC cell proliferation, migration and invasion; in vivo tumor growth was assessed in xenograft mice model.

RESULTS

TP73-AS1 was up-regulated in both CRC tissues and CRC cell lines. Overexpression of TP73-AS1 was associated with metastasis and advanced clinical stages in CRC patients. Overexpression of TP73-AS1 promoted CRC cell growth, proliferation, migration and invasion in vitro; and knockdown of TP73-AS1 significantly inhibited CRC cell growth, proliferation, migration and invasion in vitro as well as tumor growth in vivo. Bioinformatics analysis and luciferase reporter assay indicated that TP73-AS1 could bind directly with miR-194, and TP73-AS1 negatively regulated the expression of miR-194 in CRC cells. Further study indicated that miR-194 negatively regulated the downstream target of transforming growth factor alpha (TGFα) via targeting its 3' untranslated region, and TP73-AS1 positively regulated the expression of TGFα in CRC cells. Moreover, overexpression of miR-194 suppressed CRC cell proliferation and invasion, and attenuated the effects of TP73-AS1 overexpression on CRC cell proliferation and invasion. Silence of TGFα inhibited CRC cell proliferation and invasion, and also reversed the effects of TP73-AS1 overexpression on CRC cell proliferation and invasion.

CONCLUSIONS

this study demonstrated that TP73-AS1 regulated CRC progression by acting as a competitive endogenous RNA to sponge miR-194 to modulate the expression of TGFα.

Long noncoding RNA TP73-AS1 promotes non-small cell lung cancer progression by competitively sponging miR-449a/EZH2

Long noncoding RNAs (lncRNAs) are a type of noncoding RNA transcript that are characterized by lack of protein-coding capacity. The vital role of lncRNAs in non-small cell lung cancer (NSCLC) is attracting increasingly more attention. In the present study, we investigate the role of lncRNA antisense RNA of the TP73 gene (TP73-AS1) in NSCLC carcinogenesis. The results demonstrate that TP73-AS1 is markedly upregulated in NSCLC tissues, and functional experiments revealed that TP73-AS1 is significantly increased in NSCLC tissue and cell lines, indicating a possible oncogenic role. In loss-of-function assays, the knockdown of TP73-AS1 inhibited NSCLC cell proliferation, tumor growth and cycle progression in vivo and in vitro. Bioinformatic tools predicted that miR-449a both targeted the 3'-UTR of TP73-AS1 and EZH2, which was confirmed using luciferase reporter assay and AGO2-dependent RNA immunoprecipitate (RIP). TP73-AS1 and miR-449a were in the same RNA-induced silencing complex (RISC). In summary, the results indicate an explicit oncogenic role of TP73-AS1 in the NSCLC tumorigenesis, suggesting a TP73-AS1-miR-449a-EZH2 axis and providing new insight for NSCLC tumorigenesis.

The Impact of lncRNA Dysregulation on Clinicopathology and Survival of Breast Cancer: A Systematic Review and Meta-analysis

Dysregulation of multiple long non-coding RNAs (lncRNAs) was reported to play major roles in breast cancer (BC). Here we aimed to collect most of the relevant literature to assess the prognostic value of lncRNAs in BC. To this end, we systematically searched PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure (CNKI), and Wanfang to identify published articles on the associations of lncRNAs with clinicopathology and/or survival of BC. Via this searching, we identified 70 articles involving 9,307 BC patients and regarding 48 lncRNAs. The expression of 41 lncRNAs was related to one or more clinicopathological parameters of BC, including tumor size; lymph node metastasis; histological grade; TNM stage; and estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) statuses (p < 0.05). Dysregulation of 28 lncRNAs was associated with overall survival, and abnormal expression of 9 lncRNAs was linked to disease-free survival. Furthermore, the expression level of 3 lncRNAs was correlated with metastasis-free survival, 3 lncRNAs with relapse-free survival, and 3 lncRNAs with progression-free survival. Our analysis showed that multiple lncRNAs were significantly associated with BC clinicopathology and survival. A large-scale study is needed to verify the prognostic value of these lncRNAs in BC.

Enhanced expression of lncRNA TP73-AS1 predicts adverse phenotypes for cholangiocarcinoma and exerts oncogenic properties in vitro and in vivo

Cholangiocarcinoma (CCA) is one of the most aggressive malignancies with increasing incidence worldwide. Various evidence documents that abnormally expressed long non-coding RNAs (lncRNAs) play important roles in tumorigenesis and progression. TP73-AS1 is a novel cancer-related lncRNA that contributes to the development of several malignancies. However, its clinical value and potential effects on CCA remains unknown. RT-qPCR was used to measure the expression levels of TP73-AS1 in CCA tissues and paired non-tumor tissues and the association between TP73-AS1 expression and clinicopathological characteristics was analyzed. In addition, the functional roles of TP73-AS1 in CCA were detected both in vitro and in vivo. The results illustrated that TP73-AS1 transcription is enhanced in both CCA tissue samples and cell lines, and this upregulation is closely associated with larger tumor size (p=0.008) and advanced TNM stage (p=0.026) in patients with CCA. For the part of functional assays, silencing of TP73-AS1 could attenuate CCA cell growth both in vitro and in vivo. Additionally, silencing of TP73-AS1 facilitates apoptosis via activating caspase-3 and caspase-9. Importantly, TP73-AS1 expression did not affect HIBEC cell growth and apoptosis. Moreover, TP73-AS1 could also facilitate migration and invasion potential of CCA cells. Collectively, these findings may help to develop a potential therapeutic target for the patients with CCA.

The lncRNA TP73-AS1 promotes ovarian cancer cell proliferation and metastasis via modulation of MMP2 and MMP9

Ovarian cancer is one of the most common gynecologic malignancy with poor prognosis. Recently, long noncoding RNAs (lncRNAs) have been identified as key regulators in cancer development. The current study investigated the role of lncRNA P73 antisense RNA 1T (TP73-AS1) in ovarian cancer. Quantitative real-time polymerase chain reaction determined the expression levels of TP-73AS1, matrix metallopeptidases (MMPs) messenger RNA. Cell proliferative ability, cell invasion, and migration were CCK-8 and colony formation, and transwell invasion and migration assays, respectively. The protein levels of matrix metallopeptidase 2 (MMP2) and MMP9 were measured by Western blot. TP73-AS1 was upregulated in the ovarian cancer tissues and ovarian cancer cells, and upregulation of TP73-AS1 was associated with poor prognosis. Knockdown of TP73-AS1 significantly suppressed cell proliferation, invasion, and migration of SKOV3 cells, and overexpression of TP73-AS1 promoted cell proliferation, invasion, and migration of OVCA429 cells. In addition, knockdown of TP73-AS1 suppressed the in vivo tumor growth. Tumor metastasis RT² profiler polymerase chain reaction array showed that MMP2 and MMP9 was significantly upregulated by TP73-AS1 overexpression in ovarian cancer cells. TP73-AS1 overexpression enhanced the expression of MMP2 and MMP9 in ovarian cancer cells. Knockdown of MMP2 and MMP9 attenuated the effects of TP73-AS1 overexpression on cell invasion and migration. The clinical data showed that MMP2 and MMP9 were upregulated and positively correlated with TP73-AS1 expression in ovarian cancer tissues. Collectively, our results demonstrated the oncogenic role of TP73-AS1 in ovarian cancer, and targeting TP73-AS1 may represent a novel approach in battling against ovarian cancer.

Natural Antisense Transcripts: Molecular Mechanisms and Implications in Breast Cancers

Natural antisense transcripts are RNA sequences that can be transcribed from both DNA strands at the same locus but in the opposite direction from the gene transcript. Because strand-specific high-throughput sequencing of the antisense transcriptome has only been available for less than a decade, many natural antisense transcripts were first described as long non-coding RNAs. Although the precise biological roles of natural antisense transcripts are not known yet, an increasing number of studies report their implication in gene expression regulation. Their expression levels are altered in many physiological and pathological conditions, including breast cancers. Among the potential clinical utilities of the natural antisense transcripts, the non-coding|coding transcript pairs are of high interest for treatment. Indeed, these pairs can be targeted by antisense oligonucleotides to specifically tune the expression of the coding-gene. Here, we describe the current knowledge about natural antisense transcripts, their varying molecular mechanisms as gene expression regulators, and their potential as prognostic or predictive biomarkers in breast cancers.

Retracted Article: SNHG3 promotes proliferation and invasion by regulating the miR-101/ZEB1 axis in breast cancer

Background: Dysregulated lncRNA expression contributes to the pathogenesis of human tumors via the lncRNAs functioning as oncogenes or tumor suppressors. Small nucleolar RNA host gene 3 (SNHG3) was demonstrated to be upregulated in breast cancer cells. However, the detailed roles and molecular mechanism of SNHG3 in breast cancer are largely unknown. Methods: The expression of SNHG3, miR-101, and zinc finger E-box-binding protein 1 (ZEB1) in breast cancer tissues and cells was detected using qRT-PCR. The effects of SNHG3 on cell proliferation and invasion were evaluated using MTT, EdU, and cell invasion assays. The protein levels of Ki-67, proliferating cell nuclear antigen (PCNA), matrix metalloproteinase MMP-2, and MMP-9 were analyzed using western blot analysis. A luciferase reporter assay and RNA immunoprecipitation (RIP) were performed to explore the interaction between SNHG3, ZEB1 and miR-101. A subcellular fractionation assay was used to detect the subcellular location of SNHG3. Xenograft tumor experiments were conducted to verify the role and mechanism of SNHG3 in breast cancer in vivo. Results: SNHG3 expression was upregulated in breast cancer tissues and correlated with poor prognosis. SNHG3 knockdown suppressed breast cancer cell proliferation and invasion, which was further demonstrated by high levels of proliferation marker proteins Ki-67/PCNA and metastasis-related proteins MMP-2/MMP-9. Additionally, SNHG3 was located in the cytoplasm of breast cancer cells. SNHG3 functioned as a molecular sponge for miR-101 in breast cancer cells. miR-101 was downregulated in breast cancer tissues and negatively correlated with SNHG3 expression. Moreover, ZEB1, a target of miR-101, was positively regulated by SNHG3 in breast cancer cells. ZEB1 mRNA expression was upregulated in breast cancer tissues and positively correlated with SNHG3 expression. Mechanistically, SNHG3 knockdown suppressed cell proliferation and invasion by upregulation of miR-101 and downregulation of ZEB1 expression in breast cancer cells in vitro and in vivo. Conclusion: SNHG3 promoted proliferation and invasion by regulating the miR-101/ZEB1 axis in breast cancer.

In the present study, we investigated the expression and functional roles of SNHG3 in breast cancer cells, as well as the underlying mechanism of SNHG3 involved in the progression of breast cancer in vitro and in vivo.