Breast Cancer Anti-Estrogen Resistance 4 (BCAR4) Drives Proliferation of IPH-926 lobular Carcinoma Cells

Quantitative systems pharmacology modeling of HER2-positive metastatic breast cancer for translational efficacy evaluation and combination assessment across therapeutic modalities

HER2-positive (HER2+) metastatic breast cancer (mBC) is highly aggressive and a major threat to human health. Despite the significant improvement in patients' prognosis given the drug development efforts during the past several decades, many clinical questions still remain to be addressed such as efficacy when combining different therapeutic modalities, best treatment sequences, interindividual variability as well as resistance and potential coping strategies. To better answer these questions, we developed a mechanistic quantitative systems pharmacology model of the pathophysiology of HER2+ mBC that was extensively calibrated and validated against multiscale data to quantitatively predict and characterize the signal transduction and preclinical tumor growth kinetics under different therapeutic interventions. Focusing on the second-line treatment for HER2+ mBC, e.g., antibody-drug conjugates (ADC), small molecule inhibitors/TKI and chemotherapy, the model accurately predicted the efficacy of various drug combinations and dosing regimens at the in vitro and in vivo levels. Sensitivity analyses and subsequent heterogeneous phenotype simulations revealed important insights into the design of new drug combinations to effectively overcome various resistance scenarios in HER2+ mBC treatments. In addition, the model predicted a better efficacy of the new TKI plus ADC combination which can potentially reduce drug dosage and toxicity, while it also shed light on the optimal treatment ordering of ADC versus TKI plus capecitabine regimens, and these findings were validated by new in vivo experiments. Our model is the first that mechanistically integrates multiple key drug modalities in HER2+ mBC research and it can serve as a high-throughput computational platform to guide future model-informed drug development and clinical translation.

Optimized Modeling of Metastatic Triple-Negative Invasive Lobular Breast Carcinoma

Invasive lobular carcinoma (ILC) is a common breast cancer subtype that is often diagnosed at advanced stages and causes significant morbidity. Late-onset secondary tumor recurrence affects up to 30% of ILC patients, posing a therapeutic challenge if resistance to systemic therapy develops. Nonetheless, there is a lack of preclinical models for ILC, and the current models do not accurately reproduce the complete range of the disease. We created clinically relevant metastatic xenografts to address this gap by grafting the triple-negative IPH-926 cell line into mouse milk ducts. The resulting intraductal xenografts accurately recapitulate lobular carcinoma in situ (LCIS), invasive lobular carcinoma, and metastatic ILC in relevant organs. Using a panel of 15 clinical markers, we characterized the intratumoral heterogeneity of primary and metastatic lesions. Interestingly, intraductal IPH-926 xenografts express low but actionable HER2 and are not dependent on supplementation with the ovarian hormone estradiol for their growth. This model provides a valuable tool to test the efficiency of potential new ILC therapeutics, and it may help detect vulnerabilities within ILC that can be exploited for therapeutic targeting.

Long non-coding RNAs: Fundamental regulators and emerging targets of cancer stem cells

Cancer is one of the leading causes of death worldwide, primarily due to the dearth of efficient therapies that result in long-lasting remission. This is especially true in cases of metastatic cancer where drug resistance causes the disease to recur after treatment. One of the factors contributing to drug resistance, metastasis, and aggressiveness of the cancer is cancer stem cells (CSCs) or tumor-initiating cells. As a result, CSCs have emerged as a potential target for drug development. In the present review, we have examined and highlighted the lncRNAs with their regulatory functions specific to CSCs. Moreover, we have discussed the difficulties and various methods involved in identifying lncRNAs that can play a particular role in regulating and maintaining CSCs. Interestingly, this review only focuses on those lncRNAs with strong functional evidence for CSC specificity and the mechanistic role that allows them to be CSC regulators and be the focus of CSC-specific drug development.

LncRNA BCAR4 promotes migration, invasion, and chemo-resistance by inhibiting miR-644a in breast cancer

BACKGROUND

Metastasis and drug resistance of breast cancer have become a barrier to treating patients successfully. Long noncoding RNAs (lncRNAs) are known as vital players in cancer development and progression.  METHODS: The RT-qPCR were used to detect the gene expression. Colony formation assay, would healing assay, and transwell assay were performed to investigate oncogenic functions of cells. CCK8 assay was used to detect the cell viability. Western blot was applied to detect the protein level. Dual-luciferase reporter assay was used to determine the relationship between molecules. Mouse orthotopic xenograft tumor models were established to evaluate the effects of BCAR4 on tumor growth and metastasis in vivo.  RESULTS: LncRNA BCAR4 was significantly increased in breast cancer patients' tissues and plasma and upregulated in breast cancer cell lines. BCAR4 upregulation was correlated with the TNM stages and decreased after surgical removal of breast tumors. Silencing of BCAR4 suppressed breast cancer cell colony formation, migration, invasion, and xenograft tumor growth and promoted chemo-sensitivity. Mechanistically, BCAR4 facilitates breast cancer migration and invasion via the miR-644a-CCR7 axis of the MAPK pathway. BCAR4 promotes ABCB1 expression indirectly by binding to and down-regulating miR-644a to induce chemo-resistance in breast cancer.

CONCLUSIONS

Our findings provide insights into the oncogenic role of BCAR4 and implicate BCAR4 as a potential diagnostic biomarker and a promising therapeutic agent to suppress metastasis and inhibit chemo-resistance of breast cancer.

Atlas of Lobular Breast Cancer Models: Challenges and Strategic Directions

Invasive lobular carcinoma (ILC) accounts for up to 15% of all breast cancer (BC) cases and responds well to endocrine treatment when estrogen receptor α-positive (ER+) yet differs in many biological aspects from other ER+ BC subtypes. Up to 30% of patients with ILC will develop late-onset metastatic disease up to ten years after initial tumor diagnosis and may experience failure of systemic therapy. Unfortunately, preclinical models to study ILC progression and predict the efficacy of novel therapeutics are scarce. Here, we review the current advances in ILC modeling, including cell lines and organotypic models, genetically engineered mouse models, and patient-derived xenografts. We also underscore four critical challenges that can be addressed using ILC models: drug resistance, lobular tumor microenvironment, tumor dormancy, and metastasis. Finally, we highlight the advantages of shared experimental ILC resources and provide essential considerations from the perspective of the European Lobular Breast Cancer Consortium (ELBCC), which is devoted to better understanding and translating the molecular cues that underpin ILC to clinical diagnosis and intervention. This review will guide investigators who are considering the implementation of ILC models in their research programs.

The role of long non-coding RNA BCAR4 in human cancers

Long non-coding RNA (lncRNA) is a type of non-coding RNA with length of nucleotides > 200 bp. Increasing evidences show that lncRNA breast cancer antiestrogen resistance 4 (BCAR4) plays an important role in the occurrence and development of various human cancers. It is found that BCAR4 is highly expressed in diverse tumor tissues and cells, and the high expression of BCAR4 is usually associated with poor prognosis. BCAR4 is considered as an oncogene in human cancers. By competing endogenous RNA (ceRNA) mechanism and regulating different signaling pathways, BCAR4 participates in the proliferation, apoptosis, migration, invasion, epithelial-mesenchymal transition (EMT), metastasis and tumorigenesis of different cancers. In addition, overexpression of BCAR4 promotes drug resistance of tumor cells. Therefore, BCAR4 is a promising biomarker for cancer diagnosis and prognosis, and it is a potential target for cancer therapy. This paper reviews studies focusing on the relationship between BCAR4 and cancers in recent years and aims to summarize the effect and mechanism of BCAR4 in human cancers.

Long non-coding RNA BCAR4 aggravated proliferation and migration in esophageal squamous cell carcinoma by negatively regulating p53/p21 signaling pathway

Long non-coding RNA breast cancer antiestrogen resistance 4 (lncRNA BCAR4) is an independent factor on the survival prognosis of patients with multiple cancers. However, the role of lncRNA BCAR4 in esophageal squamous cell cancer (ESCC) remains unknown. Here, we unraveled that lncRNA BCAR4 was upregulated in ESCC and predicted poor prognosis. Functionally, lncRNA BCAR4 knockdown induced cell apoptosis and G1/S arrest, while inhibited cell proliferation and migration in vitro; conversely, overexpressing lncRNA BCAR4 promoted proliferation and metastasis. Mechanistically, lncRNA BCAR4 sponged miR-139-3p to upregulate ELAVL1, thereby inhibiting p53/p21 pathway in ESCC cells. In conclusion, lncRNA BCAR4 promotes ESCC tumorigenesis via regulating p53/p21 signaling pathway and develops a brand-new biomarker and medicine target for ESCC.

The role of long non-coding RNAs in drug resistance of cancer

Long non-coding RNAs (lncRNAs), a class of long RNAs, are longer than 200 nucleotides in length but lack protein-coding capacity. LncRNAs, as critical genomic regulators, are involved in genomic imprinting regulation, histone modification and gene expression regulation as well as tumor initiation and progression. However, it is also found that lncRNAs are associated with drug resistance in several types of cancer. Drug resistance is an important reason for clinical chemotherapy failure, and the molecular mechanism of tumor resistance is complex, which is a process of multi-cause, multi-gene and multi-signal transduction pathway interaction. Then comprehending the mechanisms of chemoresistance will help find ways to control the tumor progression effectively. Therefore, in this review, we will construct lncRNAs /drug resistance interaction network and shed light on the role of lncRNAs in drug resistance.

9q34 & 16p13 chromosome duplications in autism

Epigenetic mechanisms, genetic factors, and environment influence the diversity of phenotypes developed in various diseases. Duplications in several chromosomes are well characterized in the scientific literature, but partial duplications, in some cases, present with milder forms of a disease and are yet to be understood. Fortunately, the identification of genetic diseases has now become more feasible due to several cytogenetic techniques such as microarray analysis and karyotyping. With these tools, together with other laboratory results and clinical examination, we are able to report the first case in the medical literature of double partial trisomy of chromosome 9q34 and 16p13.

Emerging role of long non-coding RNAs in cancer chemoresistance: unravelling the multifaceted role and prospective therapeutic targeting

Chemotherapy is one of the important treatment modules in early as well as advanced stages of cancer. However, the major limitation of chemotherapy is the development of chemoresistance in the transformed cells of cancer patients, which leads to cancer recurrence. Long non-coding RNAs (lncRNA) are the transcripts longer than 200 nucleotides in length, which are reported to associate with the initiation, progression, recurrence, and metastasis of different cancers. Several lncRNAs have been implicated in the prevalence of chemoresistant phenotypes and also in the restoration of drug sensitivity in chemoresistant cells. LncRNAs such as HOTAIR, H19, and a lot more are involved in the chemoresistance of cancer cells. Therefore, targeting the lncRNAs may serve as a novel strategy for treating chemoresistant cancer. This review throws light on the role of lncRNA in chemoresistance along with the perspective of the therapeutic targets for the treatment of multiple cancers.

The functional role of long noncoding RNA in resistance to anticancer treatment

Chemotherapy is one of the fundamental methods of cancer treatment. However, drug resistance remains the main cause of clinical treatment failure. We comprehensively review the newly identified roles of long noncoding RNAs (lncRNAs) in oncobiology that are associated with drug resistance. The expression of lncRNAs is tissue-specific and often dysregulated in human cancers. Accumulating evidence suggests that lncRNAs are involved in chemoresistance of cancer cells. The main lncRNA-driven mechanisms of chemoresistance include regulation of drug efflux, DNA damage repair, cell cycle, apoptosis, epithelial-mesenchymal transition (EMT), induction of signaling pathways, and angiogenesis. LncRNA-driven mechanisms of resistance to various antineoplastic agents have been studied extensively. There are unique mechanisms of resistance against different types of drugs, and each mechanism may have more than one contributing factor. We summarize the emerging strategies that can be used to overcome the technical challenges in studying and addressing lncRNA-mediated drug resistance.

LncRNA NONHSAT141924 promotes paclitaxel chemotherapy resistance through p-CREB/Bcl-2 apoptosis signaling pathway in breast cancer

Breast cancer is the most prevalent malignant neoplasm among women worldwide. Despite continuous improvement of breast cancer individualized comprehensive therapy, local recurrence and distant metastasis still remain the challenges due to the development of acquired drug-resistance. Long non-coding RNAs (LncRNAs) is known to participated in the development of breast cancer. However, the mechanisms of LncRNAs involving in drug-resistance of breast cancer during chemotherapy remain to be further elucidated. Aiming to screen for candidate LncRNAs responsible for breast cancer mechanism, we first investigated the expression patterns of LncRNAs and mRNAs in paired breast cancer tissues and normal tissues using Agilent Human lncRNA array. The microarray results clearly demonstrated multiple differentially expressed mRNAs and LncRNAs including LncRNA NONHSAT141924. The remarkable up-regulation of LncRNA NONHSAT141924 in breast cancer MCF-7 was further confirmed by quantitative real-time PCR. GO and KEGG pathway analysis demonstrated that LncRNA NONHSAT141924 was most closely associated with paclitaxel (PTX)-resistant phenotype. To further explore the mechanism by which LncRNA NONHSAT141924 contributes to PTX-resistant characteristics, LncRNA NONHSAT141924 was transfected into MCF-7 breast cancer cell line. Overexpression of LncRNA NONHSAT141924 significantly reduced MCF-7 cell survivability through modulation of p-CREB/Bcl-2 apoptosis signaling pathway, one of the major pathways participated in LncRNAs-mediated chemotherapy resistance. Taken together, our study provides a new LncRNA-mediated regulatory mechanism for PTX-resistance of breast cancer and suggests that therapeutic inhibition of LncRNA NONHSAT141924 might be an efficient strategy for PTX-resistant breast cancer treatment.

Long Non-Coding RNA BCAR4 Binds to miR-644a and Targets TLX1 to Promote the Progression of Bladder Cancer

Background

Bladder cancer is a serious threat to human health. It is meaningful to study the pathogenesis of bladder cancer. Long non-coding RNAs (lncRNAs) are reported to promote or inhibit bladder cancer development. However, the role of lncRNA BCAR4 in the regulation of bladder cancer remains unclear.

Purpose

This study was to explore the role of lncRNA BCAR4 in the progression of bladder cancer cell.

Methods

RT-PCR was used to examine the expression of BCAR4 and miR-644a. CCK8 assay, colony formation assay, Transwell assay were used to detect the progression of bladder cancer cells after transfecting of indicated plasmids.

Results

The expression of BCAR4 was higher in bladder cancer cell lines than normal urothelial cell line. Moreover, the expression of BCAR4 was associated with the advanced stage and metastasis of bladder cancer. Through knockdown of BCAR4, we discovered that knockdown of BCAR4 significantly decreased the proliferation, migration and invasive abilities of bladder cancer cells. Mechanically, we showed that BCAR4 can bind to miR-644a directly and targets TLX1. Moreover, we also showed that miR-644a was also highly expressed in bladder cancer cells and inhibition of miR-644a or overexpression of TLX1 can increased the migration abilities of bladder cancer caused by knockdown of BCAR4.

Conclusion

We showed that BCAR4 sponged miR-644a to modulate the expression of TLX1 and promote bladder cancer development.

Investigating the role of BCAR4 in ovarian physiology and female fertility by genome editing in rabbit

Breast Cancer Anti-estrogen Resistance 4 (BCAR4) was previously characterised in bovine species as a gene preferentially expressed in oocytes, whose inhibition is detrimental to in vitro embryo development. But its role in oogenesis, folliculogenesis and globally fertility in vivo remains unknown. Because the gene is not conserved in mice, rabbits were chosen for investigation of BCAR4 expression and function in vivo. BCAR4 displayed preferential expression in the ovary compared to somatic organs, and within the ovarian follicle in the oocyte compared to somatic cells. The transcript was detected in follicles as early as the preantral stage. Abundance decreased throughout embryo development until the blastocyst stage. A lineage of genome-edited rabbits was produced; BCAR4 expression was abolished in follicles from homozygous animals. Females of wild-type, heterozygous and homozygous genotypes were examined for ovarian physiology and reproductive parameters. Follicle growth and the number of ovulations in response to hormonal stimulation were not significantly different between genotypes. Following insemination, homozygous females displayed a significantly lower delivery rate than their heterozygous counterparts (22 ± 7% vs 71 ± 11% (mean ± SEM)), while prolificacy was 1.8 ± 0.7 vs 6.0 ± 1.4 kittens per insemination. In conclusion, BCAR4 is not essential for follicular growth and ovulation but it contributes to optimal fertility in rabbits.

The Value of LncRNA BCAR4 as a Prognostic Biomarker on Clinical Outcomes in Human Cancers

Background: This updated meta-analysis aimed to analyze available data to explore the prognostic value of long noncoding RNA breast cancer anti-estrogen resistance 4 (BCAR4) in various human malignancies. Methods: Literature retrieval was performed by systematic searching several authoritative databases, including Pubmed, PMC database, Web of Science, the Cochrane Library, Embase, and CNKI database up to Feb 10, 2019. Data were extracted and subsequently crosschecked, and discrepancies were discussed to reach consensus. Quality of the eligible studies was evaluated by Newcastle-Ottawa Scale (NOS). The fixed- or random-effects model was used to calculate the pooled the hazard ratios (HRs) or odds ratios (ORs) and the 95% confidence interval (95% CI). Publication bias was detected by using Begg's funnel plot and Egger's test. Results: A total 1,128 cancer patients from thirteen studies were included and pooled in the present meta-analysis. High expression levels of BCAR4 were correlated with unfavorable overall survival (OS) (HR=2.23, 95% CI: 1.84-2.71), but not progression-free survival (PFS) (HR=1.30, 95% CI: 0.80-2.11). Subgroup stratified analysis showed that tumor type, sample size, follow-up months, and survival analysis method did not alter the predictive value of BCAR4 on OS in various cancers. Furthermore, elevated BCAR4 level was markedly correlated with advanced clinical stage (III/IV) (OR=3.28, 95% CI: 2.33-4.60), and dramatically predicted lymph node metastasis (OR=3.00, 95% CI: 1.95-4.63, P<0.00001) and distant metastasis (OR=3.36, 95% CI: 1.88-5.98, P<0.0001), but not associated with age, gender or tumor size. No obvious heterogeneity was noted for correlation between BCAR4 expression and OS across these studies. Conclusions: High expression of BCAR4 was correlated with unfavorable overall survival outcome and clinical features including metastasis and progression, implicating an independent prognostic value for BCAR4 in human cancers.

Prognostic value of long non-coding RNA breast cancer anti-estrogen resistance 4 in human cancers: A meta-analysis

BACKGROUND

Since long non-coding RNA breast cancer anti-estrogen resistance 4 (lncRNA BCAR4) is dysregulated in various types of cancers, we conducted a meta-analysis to determine its prognostic value in cancer.

METHODS

PubMed, EMBASE database, and CENTRAL were systematically searched.Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were collected to estimate the prognostic value. Odds ratios (ORs) and their 95% CIs were used to assess the association between lncRNA BCAR4 expression and clinicopathological features, including tumor size, differentiation, lymph node metastasis, distant metastasis, and tumor stage.

RESULTS

Ten studies with 890 patients were included in this meta-analysis. The pooled results indicated that high lncRNA BCAR4 expression was associated with poor overall survival (OS) (HR 2.80, 95% CI: 2.08-3.78; P < .001). Overexpression of lncRNA BCAR4 was related to lymph node metastasis (OR 3.68, 95% CI: 2.25-6.00; P < .001), high tumor stage (OR 3.19, 95% CI: 1.98-5.13; P < .001), and distant metastasis (OR 3.83, 95% CI: 2.15-6.82; P < .001), but not to tumor size.

CONCLUSIONS

Therefore, lncRNA BCAR4 overexpression is associated with poor OS and advanced clinicopathological features, and lncRNA BCAR4 may be a novel prognostic biomarker in cancer patients. However, further high-quality studies are needed to confirm these findings.

SNAIL is induced by tamoxifen and leads to growth inhibition in invasive lobular breast carcinoma

PURPOSE

Invasive lobular carcinoma (ILC) is a histological subtype of breast cancer that is predominantly estrogen receptor alpha (ER)-positive (+) and is thus treated with endocrine therapies. Herein, we sought to understand the molecular underpinnings of the 4-hydroxytamoxifen (4OHT) resistance in ILC by assessing the potential role of the epithelial-to-mesenchymal transition transcription factor (EMT-TF) SNAIL (SNAI1).

METHODS

Using a series of breast cancer cell lines, we measured the basal, estrogen and 4OHT-induced expression of SNAIL and other EMT-TF family members by quantitative reverse transcription-polymerase chain reaction and immunoblotting. Chromatin immunoprecipitation experiments were performed to assess ER binding to the SNAIL promoter. Cell proliferation, cell cycle and apoptosis were assessed in 2D cultures. 3D growth was assessed in Matrigel and Collagen I cultures.

RESULTS

Estrogen and 4OHT induced SNAIL expression, but not that of the other EMT-TF family members SLUG (SNAI2) and SMUC (SNAI3), with the 4OHT effect being specific to the lobular but not the ductal subtype. We observed estrogen and 4OHT-induced ER recruitment to the SNAI1 promoter and high endogenous basal levels of SNAIL and several EMT-TFs in ILC cell lines. While SNAIL knockdown had a minor impact on the 4OHT partial agonism in estrogen-depleted conditions, it led to a surprising increase in cell proliferation in full serum. In complementary experiments, inducible SNAI1 overexpression caused decreased proliferation, associated with a cell cycle arrest in G₀/G₁. Additionally, apoptosis was observed in BCK4 cells.

CONCLUSION

These data suggest a previously unrecognized role for SNAIL in ILC, substantiating a context-dependent behavior for this EMT-TF.

Long Non-Coding RNAs as New Master Regulators of Resistance to Systemic Treatments in Breast Cancer

Predicting response to systemic treatments in breast cancer (BC) patients is an urgent, yet still unattained health aim. Easily detectable molecules such as long non-coding RNAs (lncRNAs) are the ideal biomarkers when they act as master regulators of many resistance mechanisms, or of mechanisms that are common to more than one treatment. These kinds of markers are pivotal in quasi-personalized treatment selection, and consequently, in improvement of outcome prediction. In order to provide a better approach to understanding development of disease and resistance to treatments, we reviewed current literature searching for lncRNA-associated systemic BC treatments including endocrine therapies, aromatase inhibitors, selective estrogen receptor modulators (SERMs), trastuzumab, paclitaxel, docetaxel, 5-fluorouracil (5-FU), anthracyclines, and cisplatin. We found that the engagement of lncRNAs in resistance is well described, and that lncRNAs such as urotelial carcinoma-associated 1 (UCA1) and regulator of reprogramming (ROR) are indeed involved in multiple resistance mechanisms, which offers tantalizing perspectives for wide usage of lncRNAs as treatment resistance biomarkers. Thus, we propose this work as the foundation for a wide landscape of functions and mechanisms that link more lncRNAs to resistance to current and new treatments in years of research to come.

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.

lncRNA BCAR4 Increases Viability, Invasion, and Migration of Non-Small Cell Lung Cancer Cells by Targeting Glioma-Associated Oncogene 2 (GLI2)

This study aimed to explore the effects of lncRNA BCAR4 on the viability and aggressiveness of non-small cell lung cancer (NSCLC) cells. qRT-PCR was used to determine the expression of BCAR4 and GLI2 downstream genes in NSCLC tissues and cell lines. Chromatin isolation by RNA purification (CHIRP) and Western blot were employed to measure the expression of the GLI2 downstream proteins. Ki-67 expression in nude mice tumors was tested by immunohistochemistry. MTT assay, wound healing assay, and Transwell assay were used to assess NSCLC cell viability and aggressiveness, respectively. Tumor xenograft was conducted to determine the effects of BCAR4 and GLI2 on NSCLC tumorigenesis in vivo. The expression of BCAR4 in NSCLC tissues and cells was significantly higher than the normal level. The overexpression of BCAR4 promoted NSCLC cell viability, migration, and invasion. The suppression of BCAR4 and GLI2 showed the opposite effects. The overexpression of BCAR4 led to an increase in the expression of GLI2 downstream proteins, while the suppression of BCAR4 and GLI2 reduced their expression. In a tumor xenograft assay, the tumors in mice of the BCAR4 group showed the biggest volume, while those in mice of the si-GLI2 group showed the smallest volume. Ki-67 showed much higher levels in the BCAR4 overexpression group but much lower levels in the si-GLI2 group. In summary, the cooperative mechanism of lncRNA BCAR4 and GLI2 might provide a new opportunity for treating NSCLC.

LncRNA BCAR4 promotes colon cancer progression via activating Wnt/β-catenin signaling

BCAR4 (Breast Cancer Anti-Estrogen Resistance 4) is a long noncoding RNA that was identified as an oncogene in breast cancer. In our research, we found that the expression level of BCAR4 was upregulated in colon cancer tissues compared to paired normal tissues. What's more, higher BCAR4 expression was correlated with lower survival rate in patients with colon cancer. Mechanistically, we showed that BCAR4 activated Wnt/β-catenin signaling in colon cancer by protecting β-catenin from degradation. We also showed that BCAR4 overexpression promoted cell proliferation and migration in colon cancer. However, silencing BCAR4 inhibited cell growth and promoted apoptosis. Besides, BCAR4 knockdown decreased tumor growth in vivo. These findings indicate that BCAR4 facilitated colon cancer progression by enhancing cell proliferation and inhibiting apoptosis via BCAR4/β-catenin axis. BCAR4 may be a useful new target for treatment of patients with colon cancer.

Long non-coding RNA00544 serves as a potential novel predictive and prognostic marker for HR+ HER2- subtype breast cancer

Luminal breast cancers (BC) account for majority of breast cancer. Due to its heterogeneity and the development of treatment resistance, luminal BC patients can vary substantially. Long noncoding RNAs (lncRNAs), as we known, is involved in breast cancer progression. Here, we aim to identify the lncRNAs which are involved in the particular type luminal BC progression. By Gene Chips analysis, we found a novel lncRNA00544, which was highly expressed in the metastatic axillary nodes compared with corresponding luminal BC tissues (fold change = 2.26, P = 0.043). This result was confirmed in luminal BC cell lines (p = 0.0113) and 49 paired breast cancer samples compared with in corresponding controls (p = 0.011). Furthermore, Kaplan-Meier survival curves of 373 breast cancer patients indicated that disease-free survival was significantly poor in breast cancer patients with high lncRNA00544 expression (p < 0.001). Univariate and multivariate Cox regression analyses showed that lncRNA00544 was a significant independent prognostic biomarker in luminal BC patients. Further analysis showed that the prognosis of high lncRNA00544 expression in breast cancer patients was actually related to HR + HER2- subtype. Together, our studies indicate that lncRNA00544 may represent a novel predictive and prognostic indicator in luminal BC patients.

Increased Expression of Long Non-Coding RNA BCAR4 Is Predictive of Poor Prognosis in Patients with Non-Small Cell Lung Cancer

Lung cancer is the most common human cancer, and the majority of lung cancer cases are categorized as non-small cell lung cancer (NSCLC). Long non-coding RNAs (lncRNAs) play key roles in the development and progression of human cancers. LncRNA breast cancer anti-estrogen resistance 4 (BCAR4) has been identified as an oncogenic lncRNA involved in the progression of breast cancer and osteosarcoma. However, the clinical significance of the lncRNA BCAR4 in NSCLC remains largely unclear. In the present study, real-time quantitative reverse transcriptase-polymerase chain reaction was used to examine the relative level of lncRNA BCAR4 in 68 cases of NSCLC tissues and their adjacent non-tumor tissues. Our data showed that the expression level of lncRNA BCAR4 was significantly higher in NSCLC tissues compared to their matched non-tumor tissues. Moreover, BCAR4 expression was significantly upregulated in NSCLC cell lines, when compared to the normal human bronchial epithelial cell line BEAS-2B. In addition, the BCAR4 expression was associated with the lymph node metastasis, distant metastasis and clinical stage, but not with the age, sex, tumor size, histological grade, and histological type. The increased expression of BCAR4 was significantly associated with poorer 5-year overall survival rate of NSCLC patients. Multivariate survival analysis indicated that BCAR4 was an independent prognostic factor for NSCLC patients. Taken together, our study suggests that the upregulation of lncRNA BCAR4 expression plays a promoting role in the malignant progression of NSCLC. Thus, BCAR4 is a potential biomarker for NSCLC progress and a therapeutic target for NSCLC.

Long non-coding RNAs in anti-cancer drug resistance

Chemotherapy is one of the basic treatments for cancers; however, drug resistance is mainly responsible for the failure of clinical treatment. The mechanism of drug resistance is complicated because of interaction among various factors including drug efflux, DNA damage repair, apoptosis and targets mutation. Long non-coding RNAs (lncRNAs) have been a focus of research in the field of bioscience, and the latest studies have revealed that lncRNAs play essential roles in drug resistance in breast cancer, gastric cancer and lung cancer, et al. Dysregulation of multiple targets and pathways by lncRNAs results in the occurrence of chemoresistance. In this review, we will discuss the mechanisms underlying lncRNA-mediated resistance to chemotherapy and the therapeutic potential of lncRNAs in future cancer treatment.