MicroRNA-124 conducts neuroprotective effect via inhibiting AK4/ATF3 after subarachnoid hemorrhage

Spontaneous subarachnoid hemorrhage (SAH) accounts for approximately 5% of all cases of stroke. SAH is correlated with elevated rates of mortality and disability. Despite significant advancements in comprehending the pathogenesis and surgical management, efficacious clinical interventions remain restricted, and the prognosis is yet to be enhanced. MicroRNAs play a crucial role in various pathological processes in organisms. Revealing these regulatory processes is conducive to the development of new treatment methods. MicroRNA-124 is highly expressed in the nervous system and has significant research value for SAH. This study aims to explore the role of miR-124 in the early post-SAH period on neural function and verify whether it is involved in the pathological and physiological processes of SAH. In this study, we used methods such as comparing the expression levels of miR-124 in cerebrospinal fluid, establishing a rat SAH model, and a mouse embryonic primary neuron hemoglobin stimulation model to verify the downstream proteins of miR-124 in SAH. Through transfection techniques, we adjusted the expression of this small RNA in Vitro and in Vivo models using miR-124 inhibitor and mimic in the primary neuron hemoglobin stimulation model and rat SAH model, and observed the phenotype. Finally, by consulting the literature and verifying in Vivo and in Vitro methods, AK4 and downstream molecule ATF3 were identified as downstream targets of miR-124.

Adenylate Kinase 4-A Key Regulator of Proliferation and Metabolic Shift in Human Pulmonary Arterial Smooth Muscle Cells via Akt and HIF-1α Signaling Pathways

Increased proliferation of pulmonary arterial smooth muscle cells (PASMCs) in response to chronic hypoxia contributes to pulmonary vascular remodeling in pulmonary hypertension (PH). PH shares numerous similarities with cancer, including a metabolic shift towards glycolysis. In lung cancer, adenylate kinase 4 (AK4) promotes metabolic reprogramming and metastasis. Against this background, we show that AK4 regulates cell proliferation and energy metabolism of primary human PASMCs. We demonstrate that chronic hypoxia upregulates AK4 in PASMCs in a hypoxia-inducible factor-1α (HIF-1α)-dependent manner. RNA interference of AK4 decreases the viability and proliferation of PASMCs under both normoxia and chronic hypoxia. AK4 silencing in PASMCs augments mitochondrial respiration and reduces glycolytic metabolism. The observed effects are associated with reduced levels of phosphorylated protein kinase B (Akt) as well as HIF-1α, indicating the existence of an AK4-HIF-1α feedforward loop in hypoxic PASMCs. Finally, we show that AK4 levels are elevated in pulmonary vessels from patients with idiopathic pulmonary arterial hypertension (IPAH), and AK4 silencing decreases glycolytic metabolism of IPAH-PASMCs. We conclude that AK4 is a new metabolic regulator in PASMCs interacting with HIF-1α and Akt signaling pathways to drive the pro-proliferative and glycolytic phenotype of PH.

MiR-3666 serves as a tumor suppressor in ovarian carcinoma by down-regulating AK4 via targeting STAT3

As a result of metastasis and high recurrence, ovarian carcinoma (OC) is one of the most frequent gynecological carcinomas affecting women up to now. In spite of advances in OC treatments, the molecular mechanisms underlying OC progression are still needed to be deeply understood. MicroRNAs (miRNAs) with aberrant expressions are widely known to regulate target genes so as to mediate diverse biological activities of tumor cells. In the present study, we inspected the expression profile and latent mechanism of miR-3666 in OC. First of all, our research revealed the down-regulated miR-3666 in OC cells. Furthermore, miR-3666 up-regulation could repress cell proliferation and migration as well as induce cell apoptosis in OC. In addition, we unmasked that miR-3666 targeted STAT3 (signal transducer and activator of transcription 3) and further down-regulated STAT3 expression. Moreover, adenylate kinase 4 (AK4) was transcriptionally enhanced by STAT3, and then miR-3666 restrained AK4 expression by mediating STAT3. In the end, rescue experiments depicted that miR-3666 suppressed the development of OC via STAT3-mediated AK4. We uncovered that miR-3666 inhibited the tumorigenesis and even development of OC via suppressing STAT3/AK4 axis, offering a novel biomarker and therapeutic target for OC.

Adenylate Kinase 4 Promotes Inflammatory Gene Expression via Hif1α and AMPK in Macrophages

Macrophages comprise the front line of defense against various pathogens. Classically activated macrophages (M1), induced by IFN-γ and LPS, highly express inflammatory cytokines and contribute to inflammatory processes. By contrast, alternatively activated macrophages (M2) are induced by IL-4 and IL-13, produce IL-10, and display anti-inflammatory activity. Adenylate kinase 4 (Ak4), an enzyme that transfers phosphate group among ATP/GTP, AMP, and ADP, is a key modulator of ATP and maintains the homeostasis of cellular nucleotides which is essential for cell functions. However, its role in regulating the function of macrophages is not fully understood. Here we report that Ak4 expression is induced in M1 but not M2 macrophages. Suppressing the expression of Ak4 in M1 macrophages with shRNA or siRNA enhances ATP production and decreases ROS production, bactericidal ability and glycolysis in M1 cells. Moreover, Ak4 regulates the expression of inflammation genes, including Il1b, Il6, Tnfa, Nos2, Nox2, and Hif1a, in M1 macrophages. We further demonstrate that Ak4 inhibits the activation of AMPK and forms a positive feedback loop with Hif1α to promote the expression of inflammation-related genes in M1 cells. Furthermore, RNA-seq analysis demonstrates that Ak4 also regulates other biological processes in addition to the expression of inflammation-related genes in M1 cells. Interestingly, Ak4 does not regulate M1/M2 polarization. Taken together, our study uncovers a potential mechanism linking energy consumption and inflammation in macrophages.

TRIM29 alters bioenergetics of pancreatic cancer cells via cooperation of miR-2355-3p and DDX3X recruitment to AK4 transcript

TRIM29 is dysregulated in pancreatic cancer and implicated in maintenance of stem-cell-like characters of pancreatic cancer cells. However, the exact mechanisms underlying oncogenic function of TRIM29 in pancreatic cancer cells remain largely unclarified. Using a global screening procedure, the current study found that adenylate kinase 4 (AK4) was profoundly reduced by TRIM29 knockdown. In addition, our data demonstrated that TRIM29 knockdown altered bioenergetics and suppressed proliferation and invasion of pancreatic cancer cells via downregulation of AK4 at the posttranscriptional level. The current study demonstrated that upregulation of microRNA-2355-3p (miR-2355-3p) upregulated AK4 expression via facilitating DDX3X recruitment to the AK4 transcript, and TRIM29 knockdown thereby destabilized the AK4 transcript via miR-2355-3p downregulation. Collectively, our study uncovers posttranscriptional stabilization of the AK4 transcript by miR-2355-3p interaction to facilitate DDX3X recruitment. Regulation of AK4 by TRIM29 via miR-2355-3p thereby provides additional information for further identification of attractive targets for therapy with pancreatic cancer.

Identification of AK4 as a novel therapeutic target for serous ovarian cancer

The present study aimed to assess the expression level of adenylate kinase 4 (AK4) in human serous ovarian cancer (SOC) tissues and investigate the possible involvement of AK4 in SOC progression. Bioinformatics analysis based on The Cancer Genome Atlas (TCGA) database and immunohistochemical (IHC) assays were performed to assess the expression level of AK4 in human SOC tissues. Clinical pathological features of patients with SOC were also evaluated. Colony formation, MTT, wound healing and Transwell assays were conducted to investigate the effects of AK4 on the proliferation, migration, and invasion of SOC cells in vitro. Mouse xenograft and lung metastasis models were developed to evaluate the effects of AK4 on tumor growth and metastasis in vivo. High expression levels of AK4 were identified in human SOC tissues compared with in normal tissues according to TCGA database and the results of IHC assays. A contribution of AK4 to tumor growth and metastasis of SOC cells in vivo was also shown. The present study confirmed the involvement of AK4 in the progression of SOC, and the results indicated that AK4 could serve as a novel therapeutic target for SOC treatment.

Knockdown of LINC00662 represses AK4 and attenuates radioresistance of oral squamous cell carcinoma

Background

LncRNAs play crucial roles in the development of carcinomas. However, the investigation of LINC00662 in Oral squamous cell carcinoma (OSCC) is still elusive.

Methods

qRT-PCR assay tested the expression levels of LINC00662, hnRNPC and AK4. With exposure to irradiation, CCK-8, colony formation, flow cytometry and western blot experiments, respectively determined the function of LINC00662 in the radiosensitivity of OSCC cells. Then RIP and western blot assays affirmed the interaction between hnRNPC protein and LINC00662 or AK4. Finally, rescue assays validated the regulation mechanism of LINC00662 in the radioresistance of OSCC.

Results

In the present report, LINC00662 was overexpressed in OSCC and its silencing could alleviate radioresistance of OSCC. Furthermore, the interaction between hnRNPC protein and LINC00662 or AK4 was uncovered. Besides, LINC00662 regulated AK4 mRNA stability through binding to hnRNPC protein. To sum up, LINC00662 modulated the radiosensitivity of OSCC cells via hnRNPC-modulated AK4.

Conclusion

The molecular mechanism of the LINC00662/hnRNPC/AK4 axis was elucidated in OSCC, which exhibited a promising therapeutic direction for patients with OSCC.

Knockdown of circ-ABCB10 promotes sensitivity of lung cancer cells to cisplatin via miR-556-3p/AK4 axis

BACKGROUND

Due to the acquired drug resistance, the potency of cisplatin-based chemotherapy is limited in lung cancer, which is a big obstacle in clinical treatment of lung cancer. Abundant evidence has revealed that circular RNAs (circRNAs) exerted facilitating or suppressive function on the tumorigenesis of multiple cancers. The oncogenic role of circ-ABCB10 in breast cancer and clear cell renal cell carcinoma has been validated in recent researches. However, the regulatory mechanism of circ-ABCB10 and its relation to cellular sensitivity to cisplatin in lung cancer is poorly understood.

METHODS

The expression and characteristic of circ-ABCB10 were analyzed by RT-qPCR and nucleic acid electrophoresis. CCK-8, colony formation, TUNEL and transwell assays were applied to probe the role of FOXD3-AS1 in lung cancer. The interactions of miR-556-3p with circ-ABCB10 and AK4 were testified by luciferase reporter and RIP assays.

RESULTS

Circ-ABCB10 was markedly upregulated and featured with loop structure in lung cancer. Circ-ABCB10 depletion suppresses lung cancer progression and sensitizes lung cancer cells to cisplatin. Molecular mechanism assays manifested that circ-ABCB10 bound with miR-556-3p and negatively modulated miR-556-3p expression. Additionally, AK4 was testified to be the downstream target of miR-556-3p. More importantly, rescue assays clarified that upregulation of AK4 could reverse the cisplatin-sensitizing and tumor-suppressing effect of circ-ABCB10 knockdown on lung cancer cells.

CONCLUSIONS

Circ-ABCB10 knockdown enhances sensitivity of lung cancer cells to cisplatin by targeting miR-556-3p/AK4 axis.

Adenylate kinase 4 modulates oxidative stress and stabilizes HIF-1α to drive lung adenocarcinoma metastasis

Background

Adenylate kinase 4 (AK4) has been identified as a biomarker of metastasis in lung cancer. However, the impacts of AK4 on metabolic genes and its translational value for drug repositioning remain unclear.

Methods

Ingenuity upstream analyses were used to identify potential transcription factors that regulate the AK4 metabolic gene signature. The expression of AK4 and its upstream regulators in lung cancer patients was examined via immunohistochemistry. Pharmacological and gene knockdown/overexpression approaches were used to investigate the interplay between AK4 and its upstream regulators during epithelial-to-mesenchymal transition (EMT). Drug candidates that reversed AK4-induced gene expression were identified by querying a connectivity map. Orthotopic xenograft mouse models were established to evaluate the therapeutic efficacy of drug candidates for metastatic lung cancer.

Results

We found that HIF-1α is activated in the AK4 metabolic gene signature. IHC analysis confirmed this positive correlation, and the combination of both predicts worse survival in lung cancer patients. Overexpression of AK4 exaggerates HIF-1α protein expression by increasing intracellular ROS levels and subsequently induces EMT under hypoxia. Attenuation of ROS production with N-acetylcysteine abolishes AK4-induced invasion potential under hypoxia. Pharmacogenomics analysis of the AK4 gene signature revealed that withaferin-A could suppress the AK4-HIF-1α signaling axis and serve as a potent anti-metastatic agent in lung cancer.

Conclusions

Overexpression of AK4 promotes lung cancer metastasis by enhancing HIF-1α stability and EMT under hypoxia. Reversing the AK4 gene signature with withaferin-A may serve as a novel therapeutic strategy to treat metastatic lung cancer.

Electronic supplementary material

The online version of this article (10.1186/s13045-019-0698-5) contains supplementary material, which is available to authorized users.

The miR-199a-3p regulates the radioresistance of esophageal cancer cells via targeting the AK4 gene

Background

MiRNAs was recognized as vital regulators involved in cancer development. Radioresistance remains a major obstacle for effective treatment of cancers. The mechanisms on the miRNA-mediated radioresistance of cancers are still poorly understood. The main subject of this study is to find new miRNA biomarker that regulates the radioresistance of esophageal cancer (EC).

Methods

The cumulative dose of radiation assays were used to screen the EC radioresistant cell lines. Wound-healing and invasion assays were used to characterize the properties of these cell lines. The following survival fraction experiments were performed to test the effects of miR-199a-3p and AK4 in the radioresistance of EC. In addition, we used the luciferase reporter assays to identify the putative underlying mechanism that relates to the miR-199a-3p regulated radio-resistance.

Results

We found that the AK4 gene is one of the targets of miR-199a-3p, which promotes the radioresistance of EC cells. The following experiments by force reversal of the miR-199a-3p or AK4 levels confirmed the relationship of miR-199a-3p and AK4 with the radioresistance of EC cells. In addition, the activities of several signaling pathway were drastically altered by the forced changes of the miR-199a-3p level in EC cells.

Conclusion

Taken together, we found that miR-199a-3p can be potentially used as a biomarker for the EC radioresistance. Moreover, these results provides new insights into the mechanism on the radioresistance of EC cells, and also might guide the clinical therapy of EC.

MiR-199a-3p affects the multi-chemoresistance of osteosarcoma through targeting AK4

Background

MicroRNAs (miRNAs) play vital roles in regulating various biological processes. The dysregulations of miRNAs may result in severe human diseases, including cancer.

Methods

We performed the qRT-PCR, western blot and the luciferase reporter assays to test whether Adenylate Kinase 4 (AK4) is the target of miR-199a-3p. Up- or down-regulation of miR-199a-3p and/or the AK4 gene was done to detect their roles in OS multi-drug resistance using drug resistance profiling assays. We further predicted the putative signal pathway involved in the miR-199a-3p-mediated OS drug-resistance.

Results

The AK4 gene is one of the targets of miR-199a-3p and negatively correlates with the effect of miR-199a-3p on OS drug-resistance. In addition, the activity of the NF-кB signaling pathway was drastically altered by the forced changes of the miR-199a-3p level in OS cells.

Conclusions

Our data revealed that both miR-199a-3p and its target gene AK4 are reversely correlated with the OS drug resistance.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4460-0) contains supplementary material, which is available to authorized users.

Localization of adenylate kinase 4 in mouse tissues

Adenylate kinase (AK) is a key enzyme in the high-energy phosphoryl transfer reaction in living cells. Of its isoforms, AK4 has a similar sequence and subcellular localization to that of AK3 in the mitochondrial matrix. However, unlike AK3, AK4 lacks the guanosine triphosphate: adenosine monophosphate phosphotransferase activity. To elucidate the physiological role of AK4, we explored the protein localization of AK4 in various mouse tissues by immunohistochemical analysis. AK4 protein was detected in the kidney, liver, brain, heart, stomach, intestine, and gonads but not in the lung and spleen. Interestingly, cell-type specific expression was evident in the brain, gastrointestinal tract, and gonads. In the cerebellum, AK4 was detected in granular cells but not in Purkinje cell bodies. In the gastrointestinal tract, AK4 was highly expressed in epithelia. In the ovary, AK4 was detected in oocytes and corpora lutea. In the testis, AK4 was detected in spermatocytes but not in spermatogonia. Our findings demonstrate that AK4 localizes uniquely in a cell-type and tissue-specific manner in mouse tissues.