Long non-coding RNA Linc00312 modulates the sensitivity of ovarian cancer to cisplatin via the Bcl-2/Caspase-3 signaling pathway

Long noncoding RNA H19: functions and mechanisms in regulating programmed cell death in cancer

Long noncoding RNAs (lncRNAs) are a group of noncoding RNAs with transcript lengths of >200 nucleotides. Mounting evidence suggests that lncRNAs are closely associated with tumorigenesis. LncRNA H19 (H19) was the first lncRNA to function as an oncogene in many malignant tumors. Apart from the established role of H19 in promoting cell growth, proliferation, invasion, migration, epithelial-mesenchymal transition (EMT), and metastasis, it has been recently discovered that H19 also inhibits programmed cell death (PCD) of cancer cells. In this review, we summarize the mechanisms by which H19 regulates PCD in cancer cells through various signaling pathways, molecular mechanisms, and epigenetic modifications. H19 regulates PCD through the Wnt/β-catenin pathway and the PI3K-Akt-mTOR pathway. It also acts as a competitive endogenous RNA (ceRNA) in PCD regulation. The interaction between H19 and RNA-binding proteins (RBP) regulates apoptosis in cancer. Moreover, epigenetic modifications, including DNA and RNA methylation and histone modifications, are also involved in H19-associated PCD regulation. In conclusion, we summarize the role of H19 signaling via PCD in cancer chemoresistance, highlighting the promising research significance of H19 as a therapeutic target. We hope that our study will contribute to a broader understanding of H19 in cancer development and treatment.

Identification of long noncoding RNAs downregulated specifically in ovarian high-grade serous carcinoma

Purpose

To investigate whether long noncoding RNAs (lncRNAs) are involved in the development or malignant behavior of ovarian high-grade serous carcinoma (HGSC), we attempted to identify lncRNAs specific to HGSC.

Methods

Total RNAs were isolated from HGSC, normal ovarian, and fallopian tube tissue samples and were subjected to a PCR array that can analyze 84 cancer-associated lncRNAs. The lncRNAs that were upregulated and downregulated in HGSC in comparison to multiple samples of normal ovary and fallopian tube were validated by real-time RT-PCR. To infer the function, ovarian cancer cell lines that overexpress the identified lncRNAs were established, and the activation of cell proliferation, migration, and invasion was analyzed.

Results

Eleven lncRNAs (ACTA2-AS1, ADAMTS9-AS2, CBR3-AS1, HAND2-AS1, IPW, LINC00312, LINC00887, MEG3, NBR2, TSIX, and XIST) were downregulated in HGSC samples. We established the cell lines that overexpress ADAMTS9-AS2, CBR3-AS1, or NBR2. In cell lines overexpressing ADAMTS9-AS2, cell proliferation was suppressed, but migration and invasion were promoted. In cell lines overexpressing CBR3-AS1 or NBR2, cell migration tended to be promoted, although cell proliferation and invasion were unchanged.

Conclusion

We identified eleven lncRNAs that were specifically downregulated in HGSC. Of these, CBR3-AS1, NBR2, and ADAMTS9-AS2 had unique functions in the malignant behaviors of HGSC.

Non-coding RNAs in gynecologic cancer

The term "gynecologic cancer" pertains to neoplasms impacting the reproductive tissues and organs of women encompassing the endometrium, vagina, cervix, uterus, vulva, and ovaries. The progression of gynecologic cancer is linked to various molecular mechanisms. Historically, cancer research primarily focused on protein-coding genes. However, recent years have unveiled the involvement of non-coding RNAs (ncRNAs), including microRNAs, long non-coding RNAs (LncRNAs), and circular RNAs, in modulating cellular functions within gynecological cancer. Substantial evidence suggests that ncRNAs may wield a dual role in gynecological cancer, acting as either oncogenic or tumor-suppressive agents. Numerous clinical trials are presently investigating the roles of ncRNAs as biomarkers and therapeutic agents. These endeavors may introduce a fresh perspective on the diagnosis and treatment of gynecological cancer. In this overview, we highlight some of the ncRNAs associated with gynecological cancers.

Bibliometric and visualized analysis of drug resistance in ovarian cancer from 2013 to 2022

Objective

As one of the cancers that seriously threatens women's health, ovarian cancer has a high morbidity and mortality rate. Surgery and chemotherapy are the basic treatment strategies for ovarian cancer, and chemotherapy resistance is a significant factor in affecting the prognosis, survival cycle, and recurrence of ovarian cancer. This article aims to analyze articles about ovarian cancer and drug resistance via bibliometric software, offering new ideas and directions for researchers in this field.

Methods

Both Citespace and Vosviewer are bibliometric software on the Java platform. Articles were collected on ovarian cancer and drug resistance in the Web of Science Core Collection database from 2013 to 2022. The countries, institutions, journals, authors, keywords, and references were analyzed, and the development status of this field was indicated from multiple perspectives.

Results

Studies on ovarian cancer and drug resistance generally showed an increasing trend from 2013 to 2022. The People's Republic of China and Chinese institutions contributed more to this field. Gynecologic Oncology published the most articles, and the journal with the most citations was Cancer Research. Li Li was the author with the most publications, and Siegel RL was the author with the most citations. Through burst detection, it can be found that the research hotspots in this field mainly focused on the in-depth exploration of the drug resistance mechanism of ovarian cancer and the progress of PARP inhibitors and bevacizumab in the treatment of ovarian cancer.

Conclusions

Many studies on the mechanism of drug resistance in ovarian cancer have been discovered; however, the deeper mechanism remains to be explored. Compared with traditional chemotherapy drugs, PARP inhibitors and bevacizumab have shown better efficacy, but PARP inhibitors have initially shown drug resistance. The future direction of this field should be to overcome the resistance of existing drugs and actively develop new ones.

Long noncoding RNAs as therapeutic targets to overcome chemoresistance in ovarian cancer

Long noncoding RNAs (lncRNAs) have been characterized to play an essential role in ovarian tumorigenesis via controlling a variety of cellular processes, such as cell proliferation, invasion, apoptotic death, metastasis, cell cycle, migration, metabolism, immune evasion, and chemoresistance. The one obstacle for the therapeutic efficacy is due to the development of drug resistance in ovarian cancer patients. Therefore, in this review article, we describe the role of lncRNAs in chemoresistance in ovarian cancer. Moreover, we discuss the molecular mechanism of lncRNAs-involved drug resistance in ovarian cancer. We conclude that lncRNAs could be useful targets to overcome chemoresistance and improve therapeutic outcome in ovarian cancer patients.

Linc00312 Single Nucleotide Polymorphism as Biomarker for Chemoradiotherapy Induced Hematotoxicity in Nasopharyngeal Carcinoma Patients

Background. Linc00312 is downregulated in nasopharyngeal carcinoma (NPC) and associates with poor treatment efficacy. Genetic variations are the main cause of individual differences in treatment response. The objective of this study is to explore the relationship between genetic variations of linc00312 and the risk of chemoradiotherapy induced toxic reactions in NPC patients. Methods. We used a bioinformatics approach to select 3 single nucleotide polymorphisms (SNPs) with regulatory feature in linc00312 (rs12497104, rs15734, and rs164966). 505 NPC patients receiving chemoradiotherapy with complete follow-up data were recruited. Genotyping was carried out by MassARRAY iPLEX platform. Univariate logistic and multivariate logistic regression were used to analyze the risk factors responsible for toxic reactions of NPC patients. Results. Our result demonstrated that linc00312 rs15734 ( $G>A$ ) was significantly associated with severe leukopenia in NPC patients underwent chemoradiotherapy (AA vs. GG, $\text{OR}=3.145$ , $P=0.029$ ). In addition, the risk of severe leukopenia was remarkably increased to 5.635 times ( $P=0.034$ ) in female with rs15734 AA genotype compared to male with rs15734 GG genotype. Moreover, patients with rs12497104 ( $G>A$ ) AA genotype showed a 67.5% lower risk of thrombocytopenia than those with GG genotype ( $P=0.030$ ). Remarkably, the younger patients ( $\text{age}<47$ ) with rs12497104 AA genotype displayed a 90% decreased risk of thrombocytopenia compared with older patients ( $\text{age}\ge 47$ ) carrying rs12497104 GG genotype ( $P=0.030$ ). Conclusions. Genetic variations of linc00312 affect the risk of chemoradiotherapy induced hematotoxicity in nasopharyngeal carcinoma patients and may serve as biomarkers for personalized medicine.

Long non‑coding RNA HAND2‑AS1/miR‑106a/PTEN axis re‑sensitizes cisplatin‑resistant ovarian cells to cisplatin treatment

Cisplatin (DDP) resistance in patients suffering from ovarian cancer is a considerable hurdle to successful treatment. The present study aimed to identify a possible long non‑coding RNA (lncRNA)‑microRNA (miRNA)‑mRNA axis participating in ovarian cancer DDP‑resistance based on the critical roles of non‑coding RNAs, including lncRNAs and miRNAs, in carcinogenesis. According to online data and experimental results, lncRNA HAND2‑AS1 expression was significantly downregulated within ovarian carcinoma, especially within recurrent and DDP‑resistant ovarian carcinoma. The expression of HAND2‑AS1 was also shown to be markedly inhibited in SKOV3/DDP (DDP) cells with resistance to DDP. In SKOV3/DDP cells, HAND2‑AS1 overexpression inhibited cell viability and promoted cell apoptosis upon DDP treatment through the Bcl‑2/caspase‑3 apoptotic signaling. It was hypothesized that PTEN mRNA expression was also markedly inhibited in SKOV3/DDP ovarian cancer cells, while HAND2‑AS1 overexpression rescued PTEN proteins and blocked PI3K/AKT signaling activation. Moreover, miR‑106a was found to bind directly to PTEN 3' UTR and HAND2‑AS1. Upon DDP treatment, miR‑106a overexpression in SKOV3/DDP cells promoted cell viability. It inhibited cell apoptosis through the Bcl‑2/caspase‑3 apoptotic signaling pathway and downregulated the protein levels of PTEN and upregulated PI3K/AKT signaling activity. Furthermore, miR‑106a overexpression partially reversed the effect of HAND2‑AS1 overexpression upon PTEN proteins and SKOV3/DDP cell proliferation upon DDP treatment. In conclusion, a lncRNA HAND2‑AS1/miR‑106a/PTEN axis that re‑sensitizes DDP‑resistant SKOV3/DDP cells to DDP treatment has been established.

Genetic Polymorphisms of Long Non-coding RNA Linc00312 Are Associated With Susceptibility and Predict Poor Survival of Nasopharyngeal Carcinoma

Background

Linc00312 is dysregulated in nasopharyngeal carcinoma (NPC) and participates in the initiation and progression of NPC. Our previous studies suggested that linc00312 was able to enhance the sensitivity of NPC cells to irradiation and NPC patients with higher expression of linc00312 was associated with better short-term curative effect and overall survival. The single nucleotide polymorphisms (SNPs) of lncRNAs may influence the disease course and outcome by affecting the expression, secondary structure or function of lncRNAs. However, the role of SNPs in linc00312 on the occurrence and survival of NPC remains unknown.

Methods

We recruited 684 NPC patients and 823 healthy controls to evaluate the association between linc00312 SNPs and NPC susceptibility by using multivariate logistic regression analysis. Kaplan-Meier analysis and Cox proportional hazards regression were applied to assess the effect of linc00312 SNPs on the survival of NPC patients. The relative expression of linc00312 in NPC tissues was determined by real-time PCR. The interaction between linc00312 and mir-411-3p was explored by luciferase reporter assay. In silico prediction of the changes on linc00312 folding structure was conducted by RNAfold WebServer.

Result

We demonstrated that rs12497104 (G > A) GA genotype carriers had a higher risk than others for suffering from NPC (GA vs GG, OR = 1.437, P = 0.003). Besides, patients with rs12497104 AA genotype showed a poorer overall survival in contrast to GG genotype (AA vs GG, HR = 2.117, P = 0.011). In addition, the heterozygous carriers of rs15734 (G > A) and rs164966 (A > G) were correlated with decreased risk of NPC (GA vs GG, OR = 0.778, P = 0.031; GA vs AA, OR = 0.781, P = 0.033, respectively). We found that the three SNPs might influence the expression of linc00312 in a genotype specific feature. The local centroid secondary structure as well as the minimum free energy of linc00312 were changed following the candidate SNPs alterations. Besides, we revealed that the G to A alteration at rs12497104 disrupted the binding between mir-411-3p and linc00312.

Conclusion

Our results indicated genetic polymorphisms of linc00312 might serve as potential biomarkers for NPC carcinogenesis and prognosis.

HOTTIP-miR-205-ZEB2 Axis Confers Cisplatin Resistance to Ovarian Cancer Cells

Ovarian cancer is a deadly gynecological malignancy with resistance to cisplatin a major clinical problem. We evaluated a role of long non-coding (lnc) RNA HOTTIP (HOXA transcript at the distal tip) in the cisplatin resistance of ovarian cancer cells, using paired cisplatin sensitive and resistant A2780 cells along with the SK-OV-3 cells. HOTTIP was significantly elevated in cisplatin resistant cells and its silencing reversed the cisplatin resistance of resistant cells. HOTTIP was found to sponge miR-205 and therefore HOTTIP silenced cells had higher levels of miR-205. Downregulation of miR-205 could attenuate HOTTIP-silencing effects whereas miR-205 upregulation in resistant cells was found to re-sensitize cells to cisplatin. HOTTIP silencing also led to reduced NF-κB activation, clonogenic potential and the reduced expression of stem cell markers SOX2, OCT4, and NANOG, an effect that could be attenuated by miR-205. Finally, ZEB2 was identified as the gene target of miR-205, thus completing the elucidation of HOTTIP-miR-205-ZEB2 as the novel axis which is functionally involved in the determination of cisplatin resistance in ovarian cancer cells.

The evolving complexity of DNA damage foci: RNA, condensates and chromatin in DNA double-strand break repair

Formation of biomolecular condensates is increasingly recognized as a mechanism employed by cells to deal with stress and to optimize enzymatic reactions. Recent studies have characterized several DNA repair foci as phase-separated condensates, behaving like liquid droplets. Concomitantly, the apparent importance of long non-coding RNAs and RNA-binding proteins for the repair of double-strand breaks has raised many questions about their exact contribution to the repair process. Here we discuss how RNA molecules can participate in condensate formation and how RNA-binding proteins can act as molecular scaffolds. We furthermore summarize our current knowledge about how properties of condensates can influence the choice of repair pathway (homologous recombination or non-homologous end joining) and identify the open questions in this field of emerging importance.

RAMS11 promotes CRC through mTOR-dependent inhibition of autophagy, suppression of apoptosis, and promotion of epithelial-mesenchymal transition

BACKGROUND

Long non-coding RNAs (lncRNAs), a class of non-coding RNAs (ncRNAs) associated with diverse biological processes of cells. Over the past decades, cumulating research evidences revealed that abnormal expressions of lncRNAs are associated with colorectal cancer (CRC) initiation, progression, metastasis, and resistance to therapies. Moreover, their usefulness as candidate biomarkers for CRC diagnosis and prognosis are well evident throughout previous literature. In the current study, we examined the role and molecular mechanisms of newly identified lncRNA named RNA associated with metastasis-11 (RAMS11) in CRC development.

METHODS

The expression of RAMS11 in CRC cell lines DLD-1, HT-29, HCT-116, and SW480 and colon normal cells CCD-112-CoN were evaluated by quantitative RT-qPCR. The results showed that the RAMS11 is significantly upregulated in CRC cell lines compared to the normal cells. The CCK-8 proliferation assay, colony formation assay, and migration assay were performed to evaluate the biological and physiological functions of RAMS11 in vitro. To decipher the molecular mechanisms of RAMS11 medicated CRC progression, we further performed western blot analysis of the key pathway proteins (e.g., AMPK, AKT, and mTOR).

RESULTS

Our results revealed that higher expression of RAMS11 is associated with increased CRC proliferation, migration, and development of metastasis. Knockdown of RAMS11 induced autophagy, apoptosis along with reduction of epithelial-mesenchymal transition (EMT) suggesting that RAMS11 is involved in CRC progression. The molecular mechanisms of RAMS11 indicated that knockdown of RAMS11 significantly inhibited CRC carcinogenesis through mTOR-dependent autophagy induction.

CONCLUSIONS

In sum, our results suggested that RAMS11 is an important oncogene in CRC pathogenesis. Targeting RAMS11 could be a potential therapeutic strategy for CRC management.

Long non-coding RNAs: A view to kill ovarian cancer

An emerging role of long non-coding RNAs (lncRNAs) in tumor progression has been revealed in the last decade. Through interactions with nucleic acids and proteins, lncRNAs could act as enhancers, scaffolds or decoys for a number of oncoproteins and tumor suppressors. The aberrant lncRNA expression or mutations are often associated with changes in a variety of cellular processes, including proliferation, stress response and cell death. Here, we will focus on the tumor-associated lncRNAs in ovarian cancer according to their contribution to cancer hallmarks, such as intense proliferation, cell death resistance, altered energy metabolism, invasion and metastasis, and immune evasion. Moreover, the potential clinical implications of lncRNAs and their significance for the diagnosis, prognosis and therapy of ovarian cancer will be discussed.

LINC00184 Promotes Ovarian Cancer Cells Proliferation and Cisplatin Resistance by Elevating CNTN1 Expression via Sponging miR-1305

Objective

Cisplatin resistance is one of the main reasons for treatment failure in ovarian cancer (OC). Here, the effects of LINC00184 on cisplatin-resistant OC were studied.

Patients and Methods

LINC00184, miR-1305 and CNTN1 expression in tissues from 70 OC patients was determined by qRT-PCR, in situ hybridization and Western blot. OC cell lines and OC cisplatin-resistant cell lines were cultured. Cells were transfected using Lipofectamine 2000 and treated with 100 nM cisplatin. Cell proliferation and apoptosis were researched by the CCK-8 assay and flow cytometry. A dual-luciferase reporter gene assay and RNA pull-down were performed to explore the relationship between two genes. LINC00184, miR-1305 and CNTN1 expression in cells was detected by qRT-PCR and Western blot. An in vivo experiment was conducted using nude mice. Ki67 and CNTN1 expression and apoptosis of xenograft tumors were investigated using immunohistochemistry and a TUNEL assay.

Results

LINC00184 was up-regulated in OC clinical tissues and OC cells, especially in cisplatin-resistant OC patients and cells (p<0.01 or p<0.0001). LINC00184 overexpression significantly enhanced OC cell proliferation and cisplatin resistance, and inhibited OC cell apoptosis (p<0.05 or p<0.01). LINC00184 elevated CNTN1 expression via sponging miR-1305. LINC00184 overexpression markedly exacerbated the malignant phenotype of OC cells and cisplatin-resistant OC cells via the miR-1305/CNTN1 axis (p<0.01). Silencing of LINC00184 significantly suppressed OC cell growth and cisplatin resistance in vivo (p<0.01). LINC00184 silencing inhibited Ki67 and CNTN1 expression and promoted apoptosis of xenograft tumors. CNTN1 overexpression promoted proliferation and cisplatin resistance, and reduced apoptosis of OC cells (p<0.05 or p<0.01).

Conclusion

LINC00184 promoted OC cell proliferation and cisplatin resistance by elevating CNTN1 expression via sponging miR-1305.

LncRNA linc00312 suppresses radiotherapy resistance by targeting DNA-PKcs and impairing DNA damage repair in nasopharyngeal carcinoma

Radioresistance is the main obstacle in the clinical management of nasopharyngeal carcinoma (NPC). linc00312 is deregulated in a number of human cancers, including NPC. However, the detailed functions and underlying mechanisms of linc00312 in regulating radiosensitivity of NPC remains unknown. In this study, cox regression analysis was used to assess the association between linc00312 and NPC patients’ survival after radiotherapy. Our results reveal that linc00312 is significantly down-regulated in NPC tissues and patients with higher expression of linc00312 are significantly associated with longer overall survival and better short-term radiotherapy efficacy. Overexpression of linc00312 could increase the sensitivity of NPC cells to ionizing radiation, as indicated by clonogenic survival assay, comet assay, and flow cytometry. Mechanistically, RNA pull down and RNA immunoprecipitation were performed to investigate the binding proteins of linc00312. linc00312 directly binds to DNA-PKcs, hinders the recruitment of DNA-PKcs to Ku80, and inhibits phosphorylation of AKT–DNA–PKcs axis, therefore inhibiting the DNA damage signal sensation and transduction in the NHEJ repair pathway. In addition, linc00312 impairs DNA repair and cell cycle control by suppressing MRN–ATM–CHK2 signal and ATR–CHK1 signal. In summary, we identified DNA-PKcs as the binding protein of linc00312 and revealed a novel mechanism of linc00312 in the DNA damage response, providing evidence for a potential therapeutic strategy in NPC.

LncRNA MALAT1 Regulates the Progression and Cisplatin Resistance of Ovarian Cancer Cells via Modulating miR-1271-5p/E2F5 Axis

Background

Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) were reported to be related to the development of ovarian cancer (OC). In this study, the functional mechanisms of lncRNA metastasis associated with lung adenocarcinoma transcript 1 (MALAT1) and microRNA-1271-5p (miR-1271-5p) were explored in OC.

Methods

The level of MALAT1, miR-1271-5p, or E2F transcription factor 5 (E2F5) was detected by qRT-PCR. MTT assay, flow cytometry analysis and transwell migration and invasion assays were performed to determine cell proliferation, apoptosis, migration and invasion, respectively. E2F5 protein expression was detected by Western blot. The interaction between miR-1271-5p and MALAT1 or E2F transcription factor 5 (E2F5) was confirmed by the dual-luciferase reporter assay.

Results

MALAT1 and E2F5 level were increased, while miR-1271-5p level was decreased in cisplatin (DDP)-resistant OC tissues and cells. MALAT1 knockdown or miR-1271-5p upregulation decreased IC₅₀ of cisplatin, and inhibited cell proliferation, migration, invasion, and facilitated cell apoptosis in DDP-resistant OC cells. Moreover, MALAT1 sponged miR-1271-5p to upregulate E2F5 expression. Besides, MALAT1 knockdown decreased DDP resistance, inhibited cell proliferation, migration, invasion, and promoted cell apoptosis by sponging miR-1271-5p to downregulate E2F5 expression in DDP-resistant OC cell.

Conclusion

We demonstrated that MALAT1 mediated DDP-resistant OC development through miR-1271-5p/E2F5 axis, providing the theoretical basis for OC therapy.

Back to the Future: Rethinking the Great Potential of lncRNAS for Optimizing Chemotherapeutic Response in Ovarian Cancer

Ovarian cancer (OC) is one of the most fatal cancers in women worldwide. Currently, platinum- and taxane-based chemotherapy is the mainstay for the treatment of OC. Yet, the emergence of chemoresistance results in therapeutic failure and significant relapse despite a consistent rate of primary response. Emerging evidence substantiates the potential role of lncRNAs in determining the response to standard chemotherapy in OC. The objective of this narrative review is to provide an integrated, synthesized overview of the current state of knowledge regarding the role of lncRNAs in the emergence of resistance to platinum- and taxane-based chemotherapy in OC. In addition, we sought to develop conceptual frameworks for harnessing the therapeutic potential of lncRNAs in strategies aimed at enhancing the chemotherapy response of OC. Furthermore, we offered significant new perspectives and insights on the interplay between lncRNAs and the molecular circuitries implicated in chemoresistance to determine their impacts on therapeutic response. Although this review summarizes robust data concerning the involvement of lncRNAs in the emergence of acquired resistance to platinum- and taxane-based chemotherapy in OC, effective approaches for translating these lncRNAs into clinical practice warrant further investigation.

Long Non-coding RNAs Involved in Resistance to Chemotherapy in Ovarian Cancer

Ovarian cancer (OC) accounts for more than 150,000 deaths worldwide every year. Patients are often diagnosed at an advanced stage with metastatic dissemination. Although platinum- and taxane-based chemotherapies are effective treatment options, they are rarely curative and eventually, the disease will progress due to acquired resistance. Emerging evidence suggests a crucial role of long non-coding RNAs (lncRNAs) in the response to therapy in OC. Transcriptome profiling studies using high throughput approaches have identified differential expression patterns of lncRNAs associated with disease recurrence. Furthermore, several aberrantly expressed lncRNAs in resistant OC cells have been related to increased cell division, improved DNA repair, up-regulation of drug transporters or reduced susceptibility to apoptotic stimuli, supporting their involvement in acquired resistance. In this review, we will discuss the key aspects of lncRNAs associated with the development of resistance to platinum- and taxane-based chemotherapy in OC. The molecular landscape of OC will be introduced, to provide a background for understanding the role of lncRNAs in the acquisition of malignant properties. We will focus on the interplay between lncRNAs and molecular pathways affecting drug response to evaluate their impact on treatment resistance. Additionally, we will discuss the prospects of using lncRNAs as biomarkers or targets for precision medicine in OC. Although there is still plenty to learn about lncRNAs and technical challenges to be solved, the evidence of their involvement in OC and the development of acquired resistance are compelling and warrant further investigation for clinical applications.

Long Noncoding RNA LINC01125 Enhances Cisplatin Sensitivity of Ovarian Cancer via miR-1972

Background

Ovarian cancer (OC) is the most frequent aggressive cancer among women worldwide, and chemoresistance is the major challenge in the clinical treatment of OC. Recently, there is evidence that long noncoding RNAs (lncRNAs) are closely related to the regulation of cisplatin (CDDP) resistance in OC cells. However, whether LINC01125, a novel lncRNA, can improve the sensitivity of OC to cisplatin remains unknown.

Material/Methods

In this study, we analyzed aberrantly expressed lncRNAs in miR-200a-overexpressing OC samples by using GSE122123. LINC01125 and miR-1972 expressions were measured by qRT-PCR. The effect of LINC01125 overexpression on cell proliferation was determined by CCK-8 and colony formation assays. The sensitivity of OC cells to cisplatin was determined by CCK-8 assays. The interaction between LINC01125 and miR-1972 was verified through dual-luciferase reporter and RNA immunoprecipitation (RIP) assays, and bioinformatics analysis was performed to predict the target genes of miR-1972.

Results

Our results indicated that LINC01125 expression was significantly downregulated in CDDP-resistant OC tissues and cell lines. Overexpression of LINC01125 inhibited OC cell proliferation and enhanced the cytotoxicity of CDDP in OC cells. Additionally, LINC01125 participated in the apoptosis pathway by directly binding to miR-1972 in OC cells.

Conclusions

Therefore, we suggest that LINC01125 might act as a tumor suppressor in OC and enhances the cisplatin sensitivity of OC cells by binding to miR-1972.

Knockdown of long non-coding RNA LINC00152 increases cisplatin sensitivity in ovarian cancer cells

Drug resistance severely limits the effectiveness of chemotherapeutic treatment in ovarian cancer. The present study aimed to investigate the role of long non-coding RNA LINC00152 (LINC00152) in the cisplatin resistance of ovarian cancer. The expression level of LINC00152 was significantly increased in the ovarian cancer CoC1 and CoC1/DDP cell lines compared with the normal ovarian IOSE-80 cell line. To further investigate the function of LINC00152, small interfering RNAs (siRNAs) targeting LINC00152 were transfected into COC1 and COC1/DDP cells, which were subsequently treated with varying concentrations of cisplatin. The results revealed that LINC00152 silencing increased the apoptotic rates and enhanced the chemosensitivity of CoC1 and CoC1/DDP cells to cisplatin. Furthermore, downregulation of LINC00152 significantly decreased Bcl-2, and increased Bax and cleaved caspase-3 expression levels. Additionally, LINC00152 silencing decreased the expression of multidrug resistance-associated gene 1 (MDR1), multidrug resistance-associated protein 1 (MRP1) and glutathione S-transferase π (GSTπ). Collectively, the data demonstrated that LINC00152 knockdown increased the chemosensitivity of epithelial ovarian cancer cells to cisplatin by increasing apoptosis and decreasing the expression levels of MDR1, MRP1 and GSTπ.

MicroRNA-34a suppresses aggressiveness of hepatocellular carcinoma by modulating E2F1, E2F3, and Caspase-3

Background: Accumulating evidence suggests an antineoplastic role of MicroRNA-34a (miR-34a) in human cancer. However, its precise biological functions stay largely elusive. Purpose: Our study was aimed to investigate the impact of miR-34a on hepatocellular carcinoma (HCC) and its underlying apoptosis related mechanisms in vitro, as well as the association of miR-34a, E2F1 and E2F3 expression with patient survival of HCC using publicly accessed datasets. Methods: The HBV-expressing Hep3B and SNU-449 cell lines with or without enforced expression of miR-34a were in vitro cultured for cell proliferation, colony formation, wound healing, cell invasion, and 3D spheroid formation. Quantitative reverse transcription PCR (RT-qPCR) was performed for E2F1, E2F3 expression. Caspase-3 (CASP3) activity was determined using a CaspACE^TM Assay System. Kaplan-Meier survival curves were used to analyze the associations of miR-34a, E2F1 and E2F3 expression and overall survival in HCC. Meta-analysis was performed to examine the differential expression of E2F1 and E2F3 between primary HCC vs normal tissues. Results: The results in vitro showed that enforced miR-34a expression significantly inhibited cell proliferation, migration, and invasion of both Hep3B and SNU-449. RT-qPCR results demonstrated that miR-34a could significantly suppress E2F1 and E2F3 expression, particularly in SNU-449. CASP3 activity in both Hep3B and SNU-449 increased in miR-34a treatment group. Overexpressed E2F1 and E2F3 were observed in primary HCC vs normal tissues. Survival analyses showed that HCC patients with either high miR-34a, or low E2F1, or low E2F3 expression had better survival than their opposite counterparts, respectively. Conclusion: Our study suggested thatmiR-34a can modulate the expression of E2F1, E2F3, and CASP3 activity, thereby repressing tumor aggressiveness and expediting apoptosis in liver cancer cells.

Identification of lncRNA-miRNA-mRNA regulatory network associated with epithelial ovarian cancer cisplatin-resistant

To construct a long noncoding RNA (lncRNA)-microRNA (miRNA)-messenger RNA (mRNA) regulatory network related to epithelial ovarian cancer (EOC) cisplatin-resistant, differentially expressed genes (DEGs), differentially expressed lncRNAs (DELs), and differentially expressed miRNAs (DEMs) between MDAH and TOV-112D cells lines were identified. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted to analyze the biological functions of DEGs. Downstream mRNAs or upstream lncRNAs for miRNAs were analyzed at miRTarBase 7.0 or DIANA-LncBase V2, respectively. A total of 485 significant DEGs, 85 DELs, and 5 DEMs were identified. Protein-protein interaction (PPI) network of DEGs contrains 81 nodes and 141 edges was constructed, and 25 hub genes related to EOC cisplatin-resistant were identified. Subsequently, a lncRNA-miRNA-mRNA regulatory network contains 4 lncRNAs, 4 miRNAs, and 35 mRNAs was established. Taken together, our study provided evidence concerning the alteration genes involved in EOC cisplatin-resistant, which will help to unravel the mechanisms underlying drug resistant.

LncRNAs in ovarian cancer

Ovarian cancer is one of the most common gynecologic malignancies and has a poor prognosis. Recently, long noncoding RNAs (lncRNAs) have been identified as key regulators of cancer development. Studies have shown that the dysregulation of lncRNAs is frequently observed in ovarian cancer and greatly contributes to malignant phenotypical changes. In this review, we provide perspectives on the involvement of lncRNAs in the proliferation, apoptosis, cell cycle, migration, invasion, metastasis and drug resistance of ovarian cancer based on recent discoveries. Then, we discuss the role of lncRNAs in predicting the prognosis of ovarian cancer. Finally, we provide insight into the potential of lncRNAs for evaluating the diagnosis and prognosis of ovarian cancer.