TREG cells and CXCR3+ circulating TFH cells concordantly shape the neutralizing antibody responses in individuals who have recovered from mild COVID-19.

Regulatory T (TREG) cells are involved in the antiviral immune response in patients with COVID-19; however, whether TREG cells are involved in the neutralizing antibody (nAb) response remains unclear. Here, we found that individuals who recovered from mild but not severe COVID-19 had significantly greater frequencies of TREG cells and lower frequencies of CXCR3+ circulating TFH (cTFH) cells than healthy controls. Furthermore, TREG and CXCR3+ cTFH cells were negatively and positively correlated with the nAb responses, respectively, and TREG cells was inversely associated with CXCR3+ cTFH cells in individuals who recovered from mild COVID-19 but not in those with severe disease. Mechanistically, TREG cells inhibited memory B-cell differentiation and antibody production by limiting the activation and proliferation of cTFH cells, especially CXCR3+ cTFH cells, and functional molecule expression. This study provides novel insight showing that mild COVID-19 elicits a concerted nAb responses which are shaped by both TREG and TFH cells.

SARS-CoV-2 spike-specific TFH cells exhibit unique responses in infected and vaccinated individuals.

Long-term humoral immunity to SARS-CoV-2 is essential for preventing reinfection. The production of neutralizing antibody (nAb) and B cell differentiation are tightly regulated by T follicular help (TFH) cells. However, the longevity and functional role of TFH cell subsets in COVID-19 convalescents and vaccine recipients remain poorly defined. Here, we show that SARS-CoV-2 infection and inactivated vaccine elicited both spike-specific CXCR3+ TFH cell and CXCR3- TFH cell responses, which showed distinct response patterns. Spike-specific CXCR3+ TFH cells exhibit a dominant and more durable response than CXCR3- TFH cells that positively correlated with antibody responses. A third booster dose preferentially expands the spike-specific CXCR3+ TFH cell subset induced by two doses of inactivated vaccine, contributing to antibody maturation and potency. Functionally, spike-specific CXCR3+ TFH cells have a greater ability to induce spike-specific antibody secreting cells (ASCs) differentiation compared to spike-specific CXCR3- TFH cells. In conclusion, the persistent and functional role of spike-specific CXCR3+ TFH cells following SARS-CoV-2 infection and vaccination may play an important role in antibody maintenance and recall response, thereby conferring long-term protection. The findings from this study will inform the development of SARS-CoV-2 vaccines aiming to induce long-term protective immune memory.

Monoclonal antibodies constructed from COVID-19 convalescent memory B cells exhibit potent binding activity to MERS-CoV spike S2 subunit and other human coronaviruses.

Introduction: The Middle East respiratory syndrome coronavirus (MERS-CoV) and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are two highly contagious coronaviruses causing MERS and COVID-19, respectively, without an effective antiviral drug and a long-lasting vaccine. Approaches for diagnosis, therapeutics, prevention, etc., particularly for SARS-CoV-2 that is continually spreading and evolving, are urgently needed. Our previous study discovered that >60% of sera from convalescent COVID-19 individuals, but <8% from general population, showed binding activity against the MERS-CoV spike protein, indicating that SARS-CoV-2 infection boosted antibodies cross-reactive with MERS-CoV. Methods: To generate antibodies specific to both SARS-CoV-2 and MERS-CoV, here we screened 60 COVID-19 convalescent sera against MERS-CoV spike extracellular domain and S1 and S2 subunits. We constructed and characterized monoclonal antibodies (mAbs) from COVID-19 convalescent memory B cells and examined their binding and neutralizing activities against human coronaviruses. Results and Discussion: Of 60 convalescent serum samples, 34 showed binding activity against MERS-CoV S2, with endpoint titers positively correlated with the titers to SARS-CoV-2 S2. By sorting single memory B cells from COVID-19 convalescents, we constructed 38 mAbs and found that 11 mAbs showed binding activity with MERS-CoV S2, of which 9 mAbs showed potent cross-reactivity with all or a proportion of spike proteins of alphacoronaviruses (229E and NL63) and betacoronaviruses (SARS-CoV-1, SARS-CoV-2, OC43, and HKU1). Moreover, 5 mAbs also showed weak neutralization efficiency against MERS-CoV spike pseudovirus. Epitope analysis revealed that 3 and 8 mAbs bound to linear and conformational epitopes in MERS-CoV S2, respectively. In summary, we have constructed a panel of antibodies with broad-spectrum reactivity against all seven human coronaviruses, thus facilitating the development of diagnosis methods and vaccine design for multiple coronaviruses.

Stabilization of UCA1 by N6-methyladenosine RNA methylation modification promotes colorectal cancer progression.

BACKGROUND: UCA1 is frequently upregulated in a variety of cancers, including CRC, and it can play an oncogenic role by various mechanisms. However, how UCA1 is regulated in cancer is largely unknown. In this study, we aimed to determine whether RNA methylation at N6-methyladenosine (m6A) can impact UCA1 expression in colorectal cancer (CRC). METHODS: qRT-PCR was performed to detect the level of UCA1 and IGF2BP2 in CRC samples. CRISPR/Cas9 was employed to knockout (KO) UCA1, METTL3 and WTAP in DLD-1 and HCT-116 cells, while rescue experiments were carried out to re-express METTL3 and WTAP in KO cells. Immunoprecipitation using m6A antibody was performed to determine the m6A modification of UCA1. In vivo pulldown assays using S1m tagging combined with site-direct mutagenesis was carried out to confirm the recognition of m6A-modified UCA1 by IGF2BP2. Cell viability was measured by MTT and colony formation assays. The expression of UCA1 and IGF2BP2 in TCGA CRC database was obtained from GEPIA ( http://gepia.cancer-pku.cn ). RESULTS: Our results revealed that IGF2BP2 serves as a reader for m6A modified UCA1 and that adenosine at 1038 of UCA1 is critical to the recognition by IGF2BP2. Importantly, we showed that m6A writers, METTL3 and WTAP positively regulate UCA1 expression. Mechanically, IGF2BP2 increases the stability of m6A-modified UCA1. Clinically, IGF2BP2 is upregulated in CRC tissues compared with normal tissues. CONCLUSION: These results suggest that m6A modification is an important factor contributing to upregulation of UCA1 in CRC tissues.

AKR1B10 promotes breast cancer cell proliferation and migration via the PI3K/AKT/NF-κB signaling pathway.

BACKGROUND: Aberrant expression of Aldo-Keto reductase family 1 member B10 (AKR1B10) was associated with tumor size and metastasis of breast cancer in our published preliminary studies. However, little is known about the detailed function and underlying molecular mechanism of AKR1B10 in the pathological process of breast cancer. METHODS: The relationship between elevated AKR1B10 expression and the overall survival and disease-free survival of breast cancer patients was analyzed by Kaplan-Meier Plotter database. Breast cancer cell lines overexpressing AKR1B10 (MCF-7/AKR1B10) and breast cancer cell lines with knockdown of AKR1B10 (BT-20/shAKR1B10) were constructed to analyze the impact of AKR1B10 expression on cell proliferation and migration of breast cancer. The expression levels of AKR1B10 were detected and compared in the breast cancer cell lines and tissues by RT-qPCR, western blot and immunohistochemistry. The proliferation of breast cancer cells was monitored by CCK8 cell proliferation assay, and the migration and invasion of breast cancer cells was observed by cell scratch test and transwell assay. The proliferation- and EMT-related proteins including cyclinD1, c-myc, Survivin, Twist, SNAI1, SLUG, ZEB1, E-cadherin, PI3K, p-PI3K, AKT, p-AKT, IKBα, p-IKBα, NF-κB p65, p-NF-κB p65 were detected by western blot in breast cancer cells. MCF-7/AKR1B10 cells were treated with LY294002, a PI3K inhibitor, to consider the impact of AKR1B10 overexpression on the PI3K/AKT/NF-κB signal cascade and the presence of NF-κB p65 in nuclear. In vivo tumor xenograft experiments were used to observe the role of AKR1B10 in breast cancer growth in mice. RESULTS: AKR1B10 expression was significantly greater in breast cancer tissue compared to paired non-cancerous tissue. The expression of AKR1B10 positively correlated with lymph node metastasis, tumor size, Ki67 expression, and p53 expression, but inversely correlated with overall and disease-free survival rates. Gene Ontology analysis showed that AKR1B10 activity contributes to cell proliferation. Overexpression of AKR1B10 facilitated the proliferation of MCF-7 cells, and induced the migration and invasion of MCF-7 cells in vitro in association with induction of epithelial-mesenchymal transition (EMT). Conversely, knockdown of AKR1B10 inhibited these effects in BT-20 cells. Mechanistically, AKR1B10 activated PI3K, AKT, and NF-κB p65, and induced nuclear translocation of NF-κB p65, and expression of proliferation-related proteins including c-myc, cyclinD1, Survivin, and EMT-related proteins including ZEB1, SLUG, Twist, but downregulated E-cadherin expression in MCF-7 cells. AKR1B10 silencing reduced the phosphorylation of PI3K, AKT, and NF-κB p65, the nuclear translocation of NF-κB p65, and the expression of proliferation- and migration-related proteins in BT-20 cells. LY294002, a PI3K inhibitor, attenuated the phosphorylation of PI3K, AKT, and NF-κB p65, and the nuclear translocation of NF-κB p65. In vivo tumor xenograft experiments confirmed that AKR1B10 promoted breast cancer growth in mice. CONCLUSIONS: AKR1B10 promotes the proliferation, migration and invasion of breast cancer cells via the PI3K/AKT/NF-κB signaling pathway and represents a novel prognostic indicator as well as a potential therapeutic target in breast cancer.

[Preparation and identification of rabbit polyclonal antibody against BCR-ABL b3a2 fusion protein].

Objective To prepare and identify rabbit anti-breakpoint cluster region-Abelson leukemia virus oncogene (BCR-ABL) b3a2 subtype polyclonal antibody. Methods A peptide containing the fusion sequence of the b3a2 subtype BCR-ABL fusion protein was designed and synthesized with the purity higher than 90%. The fusion polypeptide was coupled to Keyhole Limpet hemocyanin (KLH) and used to immune New Zealand rabbits. Antiserum was purified after multiple immunizations, in addition to using the b3a2 subtype fusion polypeptide for affinity purification. Peptides harboring only BCR or c-ABL amino acid sequences were also synthesized and used to purify the antibody in the secondary purification. The antibody that only bound to part of the epitope was absorbed and removed. ELISA and Western blotting were performed to determine the antibody titer and specificity. Results The rabbit serum background was low before immunization. The titer of the polyclonal antibody reached 1:32 000 after immunization, which met the experimental requirements. Western blotting showed that the antibody could specifically recognize the b3a2 subtype fusion protein of BCR-ABL. Conclusion The experiment has prepared the specific rabbit polyclonal antibody against BCR-ABL b3a2 subtype.

AKR1B10 protects against UVC-induced DNA damage in breast cancer cells.

The cellular response to DNA damage is crucial for maintaining the integrity and stability of molecular structure. To maintain genome stability, DNA-damaged cells should be arrested so that mutations can be repaired before replication. Although several key components required for this arrest have been discovered, the majority of the pathways are still unclear. Through a number of assays, including cell viability, colony formation, and apotheosis assay, we found that AKR1B10 protected cells from UVC-induced DNA damage. Surprisingly, UVC-induced γH2AX foci and DNA double-strand breaks in the AKR1B10-overexpressing cells were ∼4-5 folds lower than those in the control group. The expression levels of AKR1B10, p53, chk1, chk2, nuclear factor (NF)-κB, and p65 showed dynamic changes in response to UVC irradiation. Our results suggested that AKR1B10 is involved in the pathway of cell cycle checkpoint and NF-κB in DNA damage. Taken together, our results suggest that AKR1B10 is involved in the repair of the DNA double-strand break, which provides a new insight into the role of AKR1B10 in DNA damage repair and indicates a new trail in tumorigenesis and cancer drug resistance.

AKR1B10 confers resistance to radiotherapy via FFA/TLR4/NF-κB axis in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is one kind of human head and neck cancers with high incidence in Southern China, Southeast Asia and North Africa. In spite of great innovations in radiation and chemotherapy treatments, the 5-year survival rate is not satisfactory. One of the main reasons is resistance to radiotherapy which leads to therapy failure and recurrence of NPC. The mechanism underlying remains to be fully elucidated. Aldo-keto reductase B10 (AKR1B10) plays a role in the formation and development of carcinomas. However, its role in resistance to radiotherapy of NPC is not clear. In this research, the relationships between AKR1B10 expression and the treatment effect of NPC patients, NPC cell survival, cell apoptosis, and DNA damage repair, as well as the effect and mechanism of AKR1B10 expression on NPC radioresistance were explored. A total of 58 paraffin tissues of NPC patients received radiotherapy were collected including 30 patients with radiosensitivity and 28 patients with radioresistance. The relationships between AKR1B10 expression and the treatment effect as well as clinical characteristics were analyzed by immuno-histochemical experiments, and the roles of AKR1B10 in cell survival, apoptosis and DNA damage repair were detected using the AKR1B10 overexpressed cell models. Furthermore the mechanism of AKR1B10 in NPC radioresistance was explored. Finally, the radioresistance effect of AKR1B10 expression was evaluated by the tumor xenograft model of nude mice and the method of radiotherapy. The results showed AKR1B10 expression level was correlated with radiotherapy resistance, and AKR1B10 overexpression promoted proliferation of NPC cells, reduced apoptosis and decreased cellular DNA damage after radiotherapy. The probable molecular mechanism is that AKR1B10 expression activated FFA/TLR4/NF-κB axis in NPC cells. This was validated by using the TLR4 inhibitor TAK242 to treat NPC cells with AKR1B10 expression, which reduced the phosphorylation of NF-κB. This study suggests that AKR1B10 can induce radiotherapy resistance and promote cell survival via FFA/TLR4/NF-κB axis in NPC, which may provide a novel target to fight against radiotherapy resistance of NPC.

Muscle atrophy induced by overexpression of ALAS2 is related to muscle mitochondrial dysfunction.

BACKGROUND: ALAS2 (delta-aminolevulinate synthase 2) is one of the two isoenzymes catalyzing the synthesis of delta-aminolevulinic acid (ALA), which is the first precursor of heme synthesis. ALAS2-overexpressing transgenic mice (Tg mice) showed syndrome of porphyria, a series of diseases related to the heme anabolism deficiency. Tg mice showed an obvious decrease in muscle size. Muscle atrophy results from a decrease in protein synthesis and an increase in protein degradation, which ultimately leads to a decrease in myofiber size due to loss of contractile proteins, organelles, nuclei, and cytoplasm. METHODS: The forelimb muscle grip strength of age-matched ALAS-2 transgenic mice (Tg mice) and wild-type mice (WT mice) were measured with an automated grip strength meter. The activities of serum LDH and CK-MB were measured by Modular DPP. The histology of skeletal muscle (quadriceps femoris and gastrocnemius) was observed by hematoxylin and eosin (HE) staining, immunohistochemistry, and transmission electron microscope. Real-time PCR was used to detect mtDNA content and UCP3 mRNA expression. Evans blue dye staining was used to detect the membrane damage of the muscle fiber. Single skeletal muscle fiber diameter was measured by single-fiber analyses. Muscle adenosine triphosphate (ATP) levels were detected by a luminometric assay with an ATP assay kit. RESULTS: Compared with WT mice, the strength of forelimb muscle and mass of gastrocnemius were decreased in Tg mice. The activities of serum CK-MB and LDH, the number of central nuclei fibers, and Evans blue positive fibers were more than those in WT mice, while the diameter of single fibers was smaller, which were associated with suppressed expression levels of MHC, myoD1, dystrophin, atrogin1, and MuRF1. Re-expression of eMyHC was only showed in the quadriceps of Tg mice, but not in WT mice. Muscle mitochondria in Tg mice showed dysfunction with descented ATP production and mtDNA content, downregulated UCP3 mRNA expression, and swelling of mitochondria. CONCLUSION: ALAS2 overexpressing-transgenic mice (Tg mice) showed muscle dystrophy, which was associated with decreased atrogin-1 and MuRF-1, and closely related to mitochondrial dysfunction.

M6A modification of circNSUN2 promotes colorectal liver metastasis.

Circular RNAs (circRNAs) are playing emerging role in the pathogenesis of cancers, but the mechanisms still unknown. In the recent issue of the Nature Communications, Chen and colleagues have demonstrated that YTHDC1 facilitates N6-methyladenosine modified circNSUN2 cytoplasmic export and the circNSUN2/IGF2BP2/HMGA2 complex stabilizes HMGA2 to promote colorectal liver metastasis. These discoveries not only expand our understanding of circRNAs biology in tumor, but also demonstrate that m6A modification plays a key role for circRNAs in RNA metabolism. Therefore, these findings indicate that circRNAs may be a new approach for therapeutic target of cancers.

Inhibition of microRNA-10b-5p up-regulates HOXD10 to attenuate Alzheimer's disease in rats via the Rho/ROCK signalling pathway.

OBJECTIVE: It is believed that microRNAs (miRNAs) participate in the pathogenesis of Alzheimer's disease (AD), but the specified function of miR-10b-5p in the disease has not been thoroughly understood. Thereafter, this research aimed to assess the function of miR-10b-5p in AD. METHODS: Rat AD models were established by injected with amyloid-ß1-42 (Aß1-42), which were mainly treated with lentivirus-miR-10b-5p inhibitor, or lentivirus-overexpressed homeobox D10 (HOXD10). MiR-10b-5p, HOXD10, RhoA, ROCK1 and ROCK2 expression in rat hippocampal tissues were determined. Afterwards, the behaviour of rats was tested, and neuronal apoptosis, pathological injury, and inflammatory factors and oxidative stress-related factors were all assessed. Finally, the target relation between miR-10b-5p and HOXD10 was detected. RESULTS: MiR-10b-5p was upregulated while HOXD10 was downregulated, and the Rho/ROCK signalling pathway was activated in hippocampal tissues of rats with AD. Inhibition of miR-10b-5p could attenuate the neuronal apoptosis, pathological injury, inflammation reaction, and oxidative stress by elevating HOXD10 and inhibiting the Rho/ROCK signalling pathway in AD rats. Moreover, HOXD10 was targeted by miR-10b-5p. CONCLUSION: Inhibited miR-10b-5p decelerated the development of AD by promoting HOXD10 and inactivating the Rho/ROCK signalling pathway, and our findings may contribute to the exploration of AD treatment.

The functions of N6-methyladenosine modification in lncRNAs.

Increasing evidence indicates that mRNAs are often subject to posttranscriptional modifications. Among them, N6-methyladenosine (m6A), which has been shown to play key roles in RNA splicing, stability, nuclear export, and translation, is the most abundant modification of RNA. Extensive studies of m6A modification of mRNAs have been carried out, while little is known about m6A modification of long non-coding RNAs (lncRNAs). Recently, several studies reported m6A modification of lncRNAs. In this review, we focus on these m6A-modified lncRNAs and discuss possible functions of m6A modification.

Improved EGFR mutation detection sensitivity after enrichment by Cas9/sgRNA digestion and PCR amplification.

The detection of circulating tumor DNA is important in cancer research and clinical practice. In the present study, we aimed to improve the sensitivity of downstream mutation detection of next-generation sequencing using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system to selectively target wild-type fragments but with low or no cleavage activity to mutant fragments, followed by amplification using polymerase chain reaction. We selected different mutant sites of epidermal growth factor receptor gene (EGFR)-exon19 deletions in patients with lung cancer and constructed mixed templates of mutant and wild-type DNA comprising ratios of 10% to 0.01% to test the effectiveness of the enrichment method. The results showed that after CRISPR/Cas9 enrichment, a low concentration of mutant DNA fragments (0.01%) could be detected by Sanger sequencing, which represented a 1000-fold increase compared with the untreated samples. We further verified the feasibility of the introduced method and obtained similar results in clinical samples from patients with non-small cell lung cancer, indicating that this method has the potential to detect low copy number mutations at the early stage.

LINC00346 promotes pancreatic cancer progression through the CTCF-mediated Myc transcription.

Although multiple factors are known to contribute to pancreatic ductal adenocarcinoma (PDAC) progression, the role of long non-coding RNAs (lncRNAs) in PDAC remains largely unknown. In this study, we present data that long intergenic non-coding RNA 346 (LINC00346) functions as a promoting factor for PDAC development. We first show that LINC00346 is highly expressed in pancreatic tumor specimens as compared to normal pancreatic tissue based on interrogation of The Cancer Genome Atlas (TCGA) pancreatic adenocarcinoma dataset. Of significance, this upregulation of LINC00346 is associated with overall survival (OS) and disease-free survival (DFS), respectively. We further show that knockout (KO) of LINC00346 impairs pancreatic cancer cell proliferation, tumorigenesis, migration, and invasion ability. Importantly, these phenotypes can be restored by LINC00346 re-expression in KO cells (i.e., rescue experiment). RNA precipitation assays combined with mass spectrometry analysis indicate that LINC00346 interacts with CCCTC-binding factor (CTCF), a known transcriptional repressor of c-Myc. This interaction between LINC00346 and CTCF prevents the binding of CTCF to c-Myc promoter, relieving the CTCF-mediated repression of c-Myc. Thus, LINC00346 functions as a positive transcriptional regulator of c-Myc. Together, these results suggest that LINC00346 contributes to PDAC pathogenesis by activating c-Myc, and as such, LINC00346 may serve as a potential biomarker and therapeutic target for PDAC.

A novel long non-coding RNA-KAT7 is low expressed in colorectal cancer and acts as a tumor suppressor.

BACKGROUND: The abnormal expression of many long non-coding RNAs (lncRNAs) has been reported in the progression of various tumors. However, the potential biological roles and regulatory mechanisms of long non-coding RNAs in the development of colorectal cancer (CRC) have not yet been fully elucidated. Therefore, it is crucial to identify that lncRNAs can be used for the clinical prevention and treatment of CRC. METHODS: In our previous work, we identificated a novel lncRNA, lncRNA-KAT7, and found that the expression of lncRNA-KAT7 in CRC tissues was significantly lower than that in matched normal intestinal tissues, and the expression in CRC cell lines was lower than that of normal intestinal epithelial cells (P < 0.05). Besides, the expression of lncRNA-KAT7 is negative associated with age, tumor size, tumor differentiation, lymph node metastasis of CRC patients. The potential biological effects and molecular mechanisms of lncRNA-KAT7 in CRC were evaluated using a series of CCK-8 assay, clone formation assay, EdU proliferation assay, scratch determination, transwell determination, western blot analysis, and nude subcutaneous tumorigenesis model construction cell and animal experiments. RESULTS: The expression of lncRNA-KAT7 in CRC tissues was lower than that in matched normal tissues and normal intestinal epithelial cells (P < 0.05). Decreased expression of lncRNA-KAT7 is associated with clinicopathological features of poor CRC patients. In vitro experiments showed that up-regulation of lncRNA-KAT7 expression in CRC cells inhibited cell proliferation and migration. In vivo animal experiments showed that the lncRNA-KAT7 also inhibited tumor growth. Western blot analysis showed that the expression of lncRNA-KAT7 was up-regulated in HCT116 cells, the expression of E-cadherin increased, and the expression of Vimentin, MMP-2 and ß-catenin protein was down-regulated so did the phosphorylation NF-κB P65. The results confirm that the expression of lncRAN-KAT7 can inhibit the malignant phenotype of CRC cells. CONCLUSIONS: Up to now, as a novel lncRNA, lncRNA-KAT7 has not any relevant research and reports. The results confirm that the expression of lncRNA-KAT7 can inhibit the malignant phenotype of CRC cells. And it can be used as a new diagnostic biomarker and therapeutic target for the development of CRC.

ZeoR: A Candidate for Assays Testing Enzymatic Activities and Off-Target Effects of Gene-Editing Enzymes.

The target lengths of gene-editing enzymes vary from approximately 20 to 80 nucleotides. The ideal reporter genes should be able to tolerate the insertion of target sequences to differentiate the phenotypic changes between in-frame and frame shift mutations for evaluating the enzymatic activities and off-target effects of gene-editing enzymes such as zinc finger nucleases, transcription activator-like effector nucleases, clustered regularly interspaced short palindromic repeats-associated system. This study demonstrated that the zeocin resistance gene (ZeoR) tolerated the insertion of long targets for a variety of tests using a strategy of inserting tandem repeats of NNT. Four genes such as CCR5, AR, HPV 16E7 early gene, and EGFR applications of ZeoR in quantitatively analyzing the off-targets of CRISPR were successful. The data indicated that evaluating the enzymatic activities and off-target effects with assays employing ZeoR had great potential in facilitating the application of gene editing to human gene therapy.

Emerging roles of lncRNAs in the post-transcriptional regulation in cancer.

Accumulating evidence indicates that long non-coding RNAs (lncRNAs) can play a pivotal role in regulation of diverse cellular processes. In particular, lncRNAs can serve as master gene regulators at transcriptional and posttranscriptional levels, leading to tumorigenesis. In this review, we discuss latest developments in lncRNA-meditated gene expression at the post-transcriptional level, including gene splicing, mRNA stability, protein stability and nuclear trafficking.

AKR1B10 promotes breast cancer cell migration and invasion via activation of ERK signaling.

BACKGROUND: Aldo-keto reductase family 1, member B10 (AKR1B10), is known to be significantly induced in the cells of various cancers such as breast cancer. However, the mechanisms of AKR1B10 promoting tumorigenesis in breast cancer remain unclear. In the present study, we demonstrated the potential role and mechanism of AKR1B10 in the invasion and migration of breast cancer cells. METHODS: The expression level of AKR1B10 in breast carcinoma, para-carcinoma and cancer tissues were detected by immunohistochemical evaluation and real-time polymerase chain reaction (RT-PCR), and the correlationships between AKR1B10 expression and clinicopathological features in breast cancer patients (n=131) were investigated. AKR1B10 was ectopically expressed in MCF-7 cells or silenced in BT-20 cells. The roles of AKR1B10 expression in the migration and invasion of MCF-7 cells and BT-20 cells were explored by wound healing assay, transwell migration assay and transwell matrigel invasion assay, and finally the activation level of extracellular signal-regulated kinase 1/2 (EKR1/2) activation and the expression level of matrix metalloproteinase-2 (MMP2) and vimentin in MCF-7 and BT-20 cells were measured by western blot. RESULTS: We found that AKR1B10 expression was increased in malignant tissues, which was correlated positively with tumor size, lymph node metastasis (p<0.05). MCF-7/AKR1B10 cells displayed a higher ability of migration (43.57±1.04%) compared with MCF-7/vector cells (29.12±1.34%) in wound healing assay, and the migrated cell number of MCF-7/AKR1B10 was more (418.43±9.62) than that of MCF-7/vector (222.43±17.75) in transwell migration assay without matrigel. We furtherly confirmed MCF-7/AKR1B10 cells invaded faster compared with MCF-7/vector cells by transwell matrigel invasion assay. Finally, we found AKR1B10 induced the migration and invasion of MCF-7 and BT-20 cells by activating EKR signaling, which promoted the expressions of MMP2 and vimentin. PD98059, a specific inhibitor of the activation of MEK, blocked the migration and invasion by inhibiting the expression of MMP2 and vimentin. CONCLUSIONS: AKR1B10 is overexpressed in breast cancer, and promotes the migration and invasion of MCF-7 and BT-20 cells by activating ERK signaling pathway.