Deletion of Rap1b, but not Rap1a or Epac1, Reduces Protein Kinase A-Mediated Thyroid Cancer

DEHP induces apoptosis and autophagy of the thyroid via Rap1 signaling pathway: In vivo and in vitro study

OBJECTIVE

DEHP has thyroid toxicity and affects thyroid function. However, the mechanism is unclear.

METHODS

The offspring of SD rats were gavaged with different doses of DEHP from in utero to 8 or 12 weeks old. We observed the thyroid morphology with HE and autophagosomes with TEM. The THs levels were tested with ELISA. The apoptosis level was tested by flow cytometry. The levels of apoptosis-related genes, autophagy-related genes and Rap1 pathway genes, were measured with qRT-PCR and Western blot. We established an MEHP-treated Nthy-ori 3-1 cell model and inhibited the Rap1 to verify the mechanism.

RESULTS

DEHP could cause pathological damage and ultrastructure damage of thyroids in offspring rats. After DEHP exposure, the THs levels were altered, the apoptosis levels increased, and autophagosomes appeared. DEHP significantly affected the levels of apoptosis-related genes and autophagy-related genes. DEHP also affected the levels of Rap1 pathway, which was correlated with the levels of apoptosis and autophagy. After inhibiting Rap1 in Nthy-ori 3-1 cells, the THs levels were altered. Rap1 pathway was inhibited and the levels of apoptosis and autophagy were down-regulated.

CONCLUSION

DEHP could induce the apoptosis and autophagy of the thyroid, and Rap1 signaling pathway may play a significant role.

EPAC1 inhibition protects the heart from doxorubicin-induced toxicity

Anthracyclines, such as doxorubicin (Dox), are widely used chemotherapeutic agents for the treatment of solid tumors and hematologic malignancies. However, they frequently induce cardiotoxicity leading to dilated cardiomyopathy and heart failure. This study sought to investigate the role of the exchange protein directly activated by cAMP (EPAC) in Dox-induced cardiotoxicity and the potential cardioprotective effects of EPAC inhibition. We show that Dox induces DNA damage and cardiomyocyte cell death with apoptotic features. Dox also led to an increase in both cAMP concentration and EPAC1 activity. The pharmacological inhibition of EPAC1 (with CE3F4) but not EPAC2 alleviated the whole Dox-induced pattern of alterations. When administered in vivo, Dox-treated WT mice developed a dilated cardiomyopathy which was totally prevented in EPAC1 knock-out (KO) mice. Moreover, EPAC1 inhibition potentiated Dox-induced cell death in several human cancer cell lines. Thus, EPAC1 inhibition appears as a potential therapeutic strategy to limit Dox-induced cardiomyopathy without interfering with its antitumoral activity.

MicroRNA expression profiling in the lungs of genetically different Ri chicken lines against the highly pathogenic avian influenza H5N1 virus

The highly pathogenic avian influenza (HPAI) virus triggers infectious diseases, resulting in pulmonary damage and high mortality in domestic poultry worldwide. This study aimed to analyze miRNA expression profiles after infection with the HPAI H5N1 virus in resistant and susceptible lines of Ri chickens.For this purpose, resistant and susceptible lines of Vietnamese Ri chicken were used based on the A/G allele of Mx and BF2 genes. These genes are responsible for innate antiviral activity and were selected to determine differentially expressed (DE) miRNAs in HPAI-infected chicken lines using small RNA sequencing. A total of 44 miRNAs were DE after 3 days of infection with the H5N1 virus. Computational program analysis indicated the candidate target genes for DE miRNAs to possess significant functions related to cytokines, chemokines, MAPK signaling pathway, ErBb signaling pathway, and Wnt signaling pathway. Several DE miRNA-mRNA matches were suggested to play crucial roles in mediating immune functions against viral evasion. These results revealed the potential regulatory roles of miRNAs in the immune response of the two Ri chicken lines against HPAI H5N1 virus infection in the lungs.

The complex, dynamic SpliceOme of the small GTPase transcripts altered by technique, sex, genetics, tissue specificity, and RNA base editing

The small GTPase family is well-studied in cancer and cellular physiology. With 162 annotated human genes, the family has a broad expression throughout cells of the body. Members of the family have multiple exons that require splicing. Yet, the role of splicing within the family has been underexplored. We have studied the splicing dynamics of small GTPases throughout 41,671 samples by integrating Nanopore and Illumina sequencing techniques. Within this work, we have made several discoveries. 1). Using the GTEx long read data of 92 samples, each small GTPase gene averages two transcripts, with 83 genes (51%) expressing two or more isoforms. 2). Cross-tissue analysis of GTEx from 17,382 samples shows 41 genes (25%) expressing two or more protein-coding isoforms. These include protein-changing transcripts in genes such as RHOA, RAB37, RAB40C, RAB4B, RAB5C, RHOC, RAB1A, RAN, RHEB, RAC1, and KRAS. 3). The isolation and library technique of the RNAseq influences the abundance of non-sense-mediated decay and retained intron transcripts of small GTPases, which are observed more often in genes than appreciated. 4). Analysis of 16,243 samples of "Blood PAXgene" identified seven genes (3.7%; RHOA, RAB40C, RAB4B, RAB37, RAB5B, RAB5C, RHOC) with two or more transcripts expressed as the major isoform (75% of the total gene), suggesting a role of genetics in altering splicing. 5). Rare (ARL6, RAB23, ARL13B, HRAS, NRAS) and common variants (GEM, RHOC, MRAS, RAB5B, RERG, ARL16) can influence splicing and have an impact on phenotypes and diseases. 6). Multiple genes (RAB9A, RAP2C, ARL4A, RAB3A, RAB26, RAB3C, RASL10A, RAB40B, and HRAS) have sex differences in transcript expression. 7). Several exons are included or excluded for small GTPase genes (RASEF, KRAS, RAC1, RHEB, ARL4A, RHOA, RAB30, RHOBTB1, ARL16, RAP1A) in one or more forms of cancer. 8). Ten transcripts are altered in hypoxia (SAR1B, IFT27, ARL14, RAB11A, RAB10, RAB38, RAN, RIT1, RAB9A) with RHOA identified to have a transient 3'UTR RNA base editing at a conserved site found in all of its transcripts. Overall, we show a remarkable and dynamic role of splicing within the small GTPase family that requires future explorations.

NKD2 is correlated with the occurrence, progression and prognosis of thyroid carcinoma

Background

Thyroid carcinoma (THCA) is the most prevalent type of tumor in endocrine system. NKD2 has been increasingly evidenced to play crucial roles in many cancers, except for THCA. We herein aimed to explore the potential role of NKD2 in THCA.

Methods

Totally 502 THCA patient data were downloaded from TCGA (The Cancer Genome Atlas) database. Overall survival was estimated by Kaplan–Meier method. Gene set enrichment analysis was conducted to obtain significant functional pathways. Wilcoxon rank sum test was used to determine the NKD2 expression differences among various groups. The NKD2 expression was validated in cell lines and tissue microarray.

Results

Significantly higher NKD2 expression was observed in THCA samples compared with adjacent samples, which were successfully verified in cell lines and tissue microarray. Moreover, NKD2 expression gradually elevated along with the increase of TNM Stage, and NKD2 expression was significantly higher in elder THCA patients compared with young patients. NKD2 highly expressed THCA patients had worse prognosis compared with NKD2 low-expressed patients. Furthermore, 53 pathways were significantly activated in the high NKD2 expression patients compared with low NKD2 expression THCA patients.

Conclusions

In summary, high NKD2 expression was probably related to the progression and poor prognosis of THCA. NKD2 is a promising prognostic biomarker and pathogenic target of THCA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-022-00853-2.

GLIS3 mediated by the Rap1/PI3K/AKT signal pathway facilitates real-ambient PM2.5 exposure disturbed thyroid hormone homeostasis regulation

Exposure to fine particulate matter (PM_2.5) could damage multiple organs and systems. Recent epidemiological studies have shown that PM_2.5 can disrupt dynamic balance of thyroid hormone (TH). However, the underlying mechanism by which PM_2.5 interferes with TH remains unclear. This study evaluated the role of Gli-similar3 (GLIS3) in the effect of PM_2.5 on TH synthesis in mice using a real-ambient exposure system, in Shijiazhuang City, Hebei Province. The PM_2.5exposure group (PM) and filtered air group (FA) were placed in the exposure device for four and eight weeks. The results showed that the PM_2.5 exposure altered the structure of the thyroid gland. Moreover, after PM_2.5 exposure for eight weeks, the exposure level of free thyroxine (FT4) increased and the expression level of thyroid stimulating hormone (TSH) decreased in serum of mice. In addition, PM_2.5 exposure significantly increased the expression of proteins related to thyroid hormone synthesis, such as sodium iodide transporter (NIS), thyroid peroxidase (TPO) and thyroglobulin (TG). Next, we found that GLIS3 and thyroid transcription factor Paired box 8 (PAX8) also increased after PM_2.5 exposure. In order to further explore the potential molecular mechanism, we carried out transcriptome sequencing. KEGG analysis of the top 10 pathways revealed that the Ras-associated protein 1 (Rap1) signaling pathway could activate transcription factors and is related to thyroid cell survival. Additionally, PM_2.5 exposure significantly increased the protein levels of Rap1 and its active form (Rap1 +GTP). We speculate that the active state of Rap1 is believed to be involved in activating the expression of transcription factor GLIS3. In conclusion, PM_2.5 exposure induces histological changes in the thyroid gland and thyroid dysfunction in mice. The exposure activates GLIS3 through the Rap1/PI3K/AKT pathway to promote the expression of proteins related to thyroid hormone synthesis, leading to increased dysregulating TH homeostasis.

Silencing of circ_0078607 prevents development of gastric cancer and inactivates the ERK1/2/AKT pathway through the miR-188-3p/RAP1B axis

The aim of this study is to explore the expression and mechanism of circ_0078607 on proliferation and apoptosis of gastric cancer. Real time PCR (RT-PCR) was performed to detect the expression of circ_0078607 in gastric cancer tumor tissues, plasma and cell lines. Cell viability was detected by cell counting Kit-8. Cell proliferation ability was assessed by cell cycle assay. The samples were analyzed by flow cytometry for the detection of apoptosis. Luciferase assay and RNA immunoprecipitation (RIP) were carried out to verify the relationship between circ_0078607 and miR-188-3p, miR-188-3p, and RAP1B. Western blot was employed to detect the protein level of RAP1B, ERK1/2 and AKT. In vivo, the effect of circ_0078607 on gastric cancer tumor growth was detected by lentivirus vector injection. Here, we found the increased level of circ_0078607 in gastric cancer tissues, gastric cancer patients plasma and cell lines. Knockdown of circ_0078607 could prevent proliferation and induce cell apoptosis in MKN-28 cells. Then we verified that circ_0078607 could interact with miR-188-3p by performed luciferase assay and RIP. Furthermore, we observed that RAP1B was a potential target of miR-188-3p. Next, we found that miR-188-3p inhibitor or overexpression of RAP1B could prevent the anti-tumor function of sh-circ_0078607. Silencing of circ_0078607 inhibited ERK1/2/AKT signal pathways via regulating miR-188-3p/RAP1B. In vivo, knockdown of circ_0078607 inhibited tumor growth. Knockdown of circ_0078607 inhibits the proliferation and induces apoptosis of gastric cancer via miR-188-3p/RAP1B signal pathway.

PRKAR1A and Thyroid Tumors

Simple Summary

In 2021 it is estimated that there will be 44,280 new cases of thyroid cancer in the United States and the incidence rate is higher in women than in men by almost 3 times. Well-differentiated thyroid cancer is the most common subtype of thyroid cancer and includes follicular (FTC) and papillary (PTC) carcinomas. Over the last decade, researchers have been able to better understand the molecular mechanisms involved in thyroid carcinogenesis, identifying genes including but not limited to RAS, BRAF, PAX8/PPARγ chromosomal rearrangements and others, as well as several tumor genes involved in major signaling pathways regulating cell cycle, differentiation, growth, or proliferation. Patients with Carney complex (CNC) have increased incidence of thyroid tumors, including cancer, yet little is known about this association. CNC is a familial multiple neoplasia and lentiginosis syndrome cause by inactivating mutations in the PRKAR1A gene which encodes the regulatory subunit type 1α of protein kinase A. This work summarizes what we know today about PRKAR1A defects in humans and mice and their role in thyroid tumor development, as the first such review on this issue.

Abstract

Thyroid cancer is the most common type of endocrine malignancy and the incidence is rapidly increasing. Follicular (FTC) and papillary thyroid (PTC) carcinomas comprise the well-differentiated subtype and they are the two most common thyroid carcinomas. Multiple molecular genetic and epigenetic alterations have been identified in various types of thyroid tumors over the years. Point mutations in BRAF, RAS as well as RET/PTC and PAX8/PPARγ chromosomal rearrangements are common. Thyroid cancer, including both FTC and PTC, has been observed in patients with Carney Complex (CNC), a syndrome that is inherited in an autosomal dominant manner and predisposes to various tumors. CNC is caused by inactivating mutations in the tumor-suppressor gene encoding the cyclic AMP (cAMP)-dependent protein kinase A (PKA) type 1α regulatory subunit (PRKAR1A) mapped in chromosome 17 (17q22–24). Growth of the thyroid is driven by the TSH/cAMP/PKA signaling pathway and it has been shown in mouse models that PKA activation through genetic ablation of the regulatory subunit Prkar1a can cause FTC. In this review, we provide an overview of the molecular mechanisms contributing to thyroid tumorigenesis associated with inactivation of the RRKAR1A gene.

Glucose deprivation affects the expression of genes encoding cAMP-activated protein kinase and related proteins in U87 glioma cells in ERN1 dependent manner

Objective. The aim of this investigation was to study the expression of genes encoding cAMP-activated protein kinase catalytic and regulatory A subunits (PRKACA and PRKAR1A) and related proteins such as cAMP-dependent protein kinase inhibitors A and G (PKIA and PKIG), catalytic subunit A of protein phosphatase 3 (PPP3CA), A-kinase anchoring protein 12 (AKAP12), and praja ring finger ubiquitin ligase 2 (PJA2) in U87 glioma cells in response to glucose deprivation in both control U87 glioma cells and cells with ERN1 (endoplasmic reticulum to nucleus signaling 1) knockdown, the major pathway of the endoplasmic reticulum stress signaling, for evaluation of possible significance of glucose deprivation in ERN1 dependent regulation of glioma growth.Methods. The expression level of PRKA related genes was studied in control (transfected by vector) and ERN1 knockdown U87 glioma cells under glucose deprivation by real-time quantitative polymerase chain reaction.Results. It was shown that the expression level of PRKACA and PKIA genes was down-regulated in control glioma cells treated by glucose deprivation, but PJA2 gene was up-regulated. At the same time, the expression of four other genes (PRKAR1A, PKIG, AKAP12, and PPP3CA) was resistant to this experimental condition. Furthermore, ERN1 knockdown of glioma cells significantly modified the effect glucose deprivation on the expression almost all studied genes. Thus, treatment of glioma cells with inhibited ERN1 enzymatic activity by glucose deprivation lead to a more significant down-regulation of the expression level of PKIA and to suppression PRKAR1A gene expressions. Moreover, the ERN1 knockdown introduced up-regulation of PKIG and AKAP12 gene expressions in glioma cells treated by glucose deprivation and eliminated the sensitivity of PJA2 gene to this experimental condition.Conclusions. Results of this investigation demonstrated that ERN1 knockdown significantly modified the sensitivity of most studied PRKA related gene expressions to glucose deprivation and that these changes are a result of complex interactions of variable endoplasmic reticulum stress related and unrelated regulatory factors and contributed to the suppression of glioma cell proliferation and their possibly chemoresistance.

MicroRNA‑15b‑5p exerts its tumor repressive role via targeting GDI2: A novel insight into the pathogenesis of thyroid carcinoma

Thyroid carcinoma (THCA) is a malignant tumor of the endocrine system. Previous studies have revealed the vital roles of microRNAs (miRNAs/miRs) in THCA procession. The present study aimed to explore the effects of miR-15b-5p on the progression of THCA and its targeting mechanism. The data of THCA and healthy samples were firstly collected from starbase2.0 and used to analyze the relationship of miR-15b-5p with THCA. Dual-luciferase assay was performed to detect the direct interaction between miR-15b-5p and the predicted target gene GDP dissociation inhibitor 2 (GDI2). The effects of miR-15b-5p and GDI2 on the overall survival of patients with THCA were analyzed using Kaplan-Meier analysis with log rank test. Cell Counting Kit-8 and Transwell assays were conducted to assess the impacts of miR-15b-5p and GDI2 on the proliferation and invasion of THCA cells. Reverse transcription-quantitative PCR and western blot analyses were performed to analyze the expression levels of the related miRNAs and proteins, respectively. miR-15b-5p was found to be downregulated both in THCA tissues and cells, and the low expression of miR-15b-5p was associated with the short overall survival time of patients. Moreover, the upregulation or downregulation of miR-15b-5p could inhibit or enhance the proliferation and invasion of THCA cells, respectively. miR-15b-5p reduced the protein expression levels of matrix metalloproteinase (MMP)2 and MMP9, which were related to cell invasion. Furthermore, GDI2, which was enhanced in THCA and related to the poor prognosis of patients with THCA, was identified as the target gene of miR-15b-5p and negatively regulated by miR-15b-5p. Additional experiments demonstrated that GDI2 overexpression could significantly reduce the antitumor effect of miR-15b-5p and its inhibitory action on the expression levels of MMP2 and MMP9. Thus, the results indicated a potential tumor suppressive role of miR-15b-5p in THCA, which was mainly exerted by targeting GDI2 and modulating MMP2 and MMP9. These findings will increase the understanding on the pathogenesis of THCA and provide novel candidates for THCA therapy.

MicroRNA-101 suppresses colorectal cancer progression by negative regulation of Rap1b

Colorectal cancer (CRC) is the fourth most lethal malignancy and is the second most common cause of cancer-associated mortality worldwide. The development of high-throughput sequencing has enabled the identification of potential biomarkers for the diagnosis and treatment of various types of cancer. Although microRNA-101 (miR-101) has been demonstrated to be a potential biomarker of CRC, its detailed mechanisms remain to be fully discovered. In the present study, overall survival analysis was applied to determine the association between miR-101 and CRC prognosis. Reverse transcription-quantitative PCR (RT-qPCR) was used to examine gene expression levels in tissues and cells. Cell proliferative and apoptotic activities were determined by MTT and flow cytometry assays, respectively. Wound healing and Transwell assays were used to examine CRC cell migration and invasion, respectively. In the present study, RT-qPCR analysis indicated that miR-101 was significantly downregulated in CRC tissues and cells. However, clinical data collected from The Cancer Genome Atlas revealed no significant association between the expression levels of miR-101 and the prognosis of CRC. Additionally, miR-101 inhibited the progression of CRC by directly binding to the 3′-untranslated region of Ras-related protein Rap1b (Rap1b). This was associated with downregulation of Rap1b expression. Furthermore, the overexpression of Rap1b promoted miR-101 mimic-attenuated CRC cell progression. The present study demonstrated that miR-101 may be involved in the repression of the CRC progression by forming a negative feedback loop with Rap1b. The findings revealed the interaction between miR-101 and Rap1b during the progression of CRC, which could aid the development of therapeutic strategies.

MRP4/ABCC4 expression is regulated by histamine in acute myeloid leukemia cells, determining cAMP efflux

Intracellular cAMP (i-cAMP) levels play an important role in acute myeloid leukemia (AML) cell proliferation and differentiation. Its levels are the result of cAMP production, degradation, and exclusion. We have previously described histamine H₂ receptors and MRP4/ABCC4 as two potential targets for AML therapy. Acting through histamine H₂ receptors, histamine increases cAMP production/synthesis, while MRP4/ABCC4 is responsible for the exclusion of this cyclic nucleotide. In this study, we show that histamine treatment induces MRP4/ABCC4 expression, augmenting cAMP efflux, and that histamine, in combination with MRP inhibitors, is able to reduce AML cell proliferation. Histamine, through histamine H₂ receptor, increases i-cAMP levels and induces MRP4 transcript and protein levels in U937, KG1a, and HL-60 cells. Moreover, histamine induces MRP4 promoter activity in HEK293T cells transfected with histamine H₂ receptor (HEK293T-H₂ R). Our results support that the cAMP/Epac-PKA pathway, and not MEK/ERK nor PI3K/AKT signaling cascades, is involved in histamine-mediated upregulation of MRP4 levels. Finally, the addition of histamine potentiates the inhibition of U937, KG1a, and HL-60 cell proliferation induced by MRP4 inhibitors. Our data highlight that the use of a poly-pharmacological approach aimed at different molecular targets would be beneficial in AML treatment.

MicroRNA-30b-5p functions as a metastasis suppressor in colorectal cancer by targeting Rap1b

Colorectal liver metastasis (CRLM) is the leading cause of death in patients with colorectal cancer (CRC). MiR-30b-5p can function as an oncogene or tumor suppressor in cancers, but its role in CRLM is still unknown. Here, we found that miR-30b-5p overexpression suppressed the invasion, migration, adhesion, and motility of HCT116 and LoVo cells. The expression of EMT (Zeb1, Snail, and vimentin) and adhesion-related proteins (p-paxillin and p-Src) was decreased. We validated Rap1b, a Ras family small GTPase that regulates cell adhesion and mobility, as the direct and functional target of miR-30b-5p. Rap1b overexpression rescued the aggressive characteristics of CRC cells that were inhibited by miR-30b-5p. Rap1b knockdown suppressed invasion and migration and decreased CRC cell-matrix adhesion and spreading, which was consistent with the results of miR-30b-5p overexpression. Further in vivo experiments demonstrated that miR-30b-5p overexpression inhibited CRLM, but Rap1b rescue attenuated the inhibitory effect of miR-30b-5p. In addition, miR-30b-5p was downregulated in CRC specimens, and Rap1b showed a negative correlation with miR-30b-5p expression in primary CRC and LM tissues. These results indicate that miR-30b-5p functions as a metastasis suppressor by targeting Rap1b and may provide a new target for the treatment of CRLM.

miR-206 inhibits thyroid cancer proliferation and invasion by targeting RAP1B

Thyroid cancer (TC) is one of the primary tumors arisen from endocrine system. The purpose of this study was to investigate the underlying mechanism by which RAP1B (Ras-related protein Rap-1b) modulates microRNA (miR)-206 related effects on TC cells. Expression of miR-206 and RAP1B was analyzed in cells and tissues. miR-206 mimics or inhibitors and RAP1B vector were used in functional experiments to investigate the effects of miR-206 and RAP1B on cell activities including proliferation, migration, and invasion. Luciferase assay was performed to explore the association between miR-206 and RAP1B. The influence of miR-206 on tumorigenesis of TC cells was investigated using an ex vivo model. Our results demonstrated the reduce of miR-206 in TC tissues and cell lines in which RAP1B was increased. Overexpression of miR-206 significantly inhibited the functional capacities of TPC-1 cells including proliferation, invasion, and migration, most likely, through reducing the expression of RAP1B. Xenograft experiment showed that increased miR-206 could effectively inhibit the tumorigenesis of TC cells. Our study showed that miR-206 negatively regulated cell activities of proliferation, invasion, and migration in TC via suppressing RAP1B expression, suggesting that miR-206 exerts a vital role in TC.