Alisertib promotes apoptosis and autophagy in melanoma through p38 MAPK-mediated aurora a signaling

The role and mechanism of biological collagen membranes in repairing cartilage injury through the p38MAPK signaling pathway

OBJECTIVE

To explore the mechanism of the p38MAPK signaling pathway in repairing articular cartilage defects with biological collagen membranes.

METHODS

Thirty-two healthy adult male rabbits were randomly divided into a control group (n = 8), model group (n = 8), treatment group (n = 8) and positive drug group (n = 8). The control group was fed normally, and the models of bilateral knee joint femoral cartilage defects were established in the other three groups. The knee cartilage defects in the model group were not treated, the biological collagen membrane was implanted in the treatment group, and glucosamine hydrochloride was intragastrically administered in the positive drug group. Twelve weeks after the operation, the repair of cartilage defects was evaluated by histological observation (HE staining and Masson staining), the degree of cartilage repair was quantitatively evaluated by the Mankin scoring system, the mRNA expression levels of p38MAPK, MMP1 and MMP13 were detected by real-time fluorescence quantitative PCR (qRT-PCR), and the protein expression levels of p38MAPK, p-p38MAPK, MMP1 and MMP13 were detected by Western blotting. The results after the construction of cartilage defects, histological staining showed that the articular cartilage wound was covered by a large capillary network, the cartilage tissue defect was serious, and a small amount of collagen fibers were formed around the wound, indicating the formation of a small amount of new bone tissue. In the treatment group and the positive drug group, the staining of cartilage matrix was uneven, the cytoplasmic staining was lighter, the chondrocytes became hypertrophic as a whole, the chondrocytes cloned and proliferated, some areas were nest-shaped, the cells were arranged disorderly, the density was uneven, and the nucleus was stained deeply. The Mankin score of the model group was significantly higher than that of the control group, while the Mankin scores of the treatment group and positive drug group were significantly lower than that of the model group. The results of qRT-PCR detection showed that compared with the control group, the expression level of the p38MAPK gene in the model group did not increase significantly, but the gene expression levels of MMP1 and MMP13 in the model group increased significantly, while the gene expression levels of MMP1 and MMP13 decreased significantly in the treatment group and positive drug group compared with the model group. The results of Western blot detection showed that compared with the control group, the expression level of p38MAPK protein in the model group was not significantly increased, but the phosphorylation level of p38MAPK protein and the protein expression levels of MMP1 and MMP13 were significantly increased in the model group, while the phosphorylation level of p38MAPK protein and the protein expression levels of MMP1 and MMP13 in the treatment group and positive drug group were significantly lower than those in the model group.

CONCLUSION

The biological collagen membrane can regulate the expression of MMP1 and MMP13 and repair the activity of chondrocytes by reducing the phosphorylation level of p38MAPK and inhibiting the activation of the p38MAPK signaling pathway, thus improving the repair effect of articular cartilage defects in rabbits. The P38MAPK signaling pathway is expected to become an important molecular target for the clinical treatment of cartilage defects in the future.

Computational and Biophysical Characterization of Heterocyclic Derivatives of Anthraquinone against Human Aurora Kinase A

Human Aurora kinase A (AurA) has recently garnered the attention of researchers worldwide as a promising effective mitotic drug target for its involvement in cancer and related inflammatory anomalies. This study has explored the binding affinity of newly identified heteroarene-fused anthraquinone derivatives against AurA. Molecular docking analyses showed that all the heteroanthraquinone compounds bind to AurA with different affinities. Molecular dynamics simulation studies revealed that the compounds maintained relatively stable binding modes in the active site pocket while inducing minimal conformational changes in the AurA structure, interacting with key residues through several noncovalent interactions, including hydrogen bonds. Fluorescence spectroscopy and biolayer interferometry binding assays with synthesized compounds against recombinantly expressed AurA further verified their binding efficacy. Naphthoisatine 3 proved to be the best binder, with compounds anthraimidazole 5 and anthrathiophene 2 showing comparable results. Overall, this study indicates decent binding of heterocyclic derivatives of anthraquinone with the target AurA, which can further be assessed by performing enzymatic assays and cellular studies. The studies also highlight the applicability of the heteroarene-fused anthraquinone scaffold to construct selective and potent inhibitors of Aurora kinases after necessary structural modifications for the development of new anticancer drugs.

Proteogenomics Reveals Perturbed Signaling Networks in Malignant Melanoma Cells Resistant to BRAF Inhibition

Analysis of nucleotide variants is a cornerstone of cancer medicine. Although only 2% of the genomic sequence is protein coding, mutations occurring in these regions have the potential to influence protein structure or modification status and may have severe impact on disease aetiology. Proteogenomics enables the analysis of sample-specific nonsynonymous nucleotide variants with regard to their effect at the proteome and phosphoproteome levels. Here, we developed a proof-of-concept proteogenomics workflow and applied it to the malignant melanoma cell line A375. Initially, we studied the resistance to serine/threonine-protein kinase B-raf (BRAF) inhibitor (BRAFi) vemurafenib in A375 cells. This allowed identification of several oncogenic nonsynonymous nucleotide variants, including a gain-of-function variant on aurora kinase A (AURKA) at F31I. We also detected significant changes in abundance among (phospho)proteins, which led to reactivation of the MAPK signaling pathway in BRAFi-resistant A375 cells. Upon reconstruction of the multiomic integrated signaling networks, we predicted drug therapies with the potential to disrupt BRAFi resistance mechanism in A375 cells. Notably, we showed that AURKA inhibition is effective and specific against BRAFi-resistant A375 cells. Subsequently, we investigated amino acid variants that interfere with protein posttranslational modification (PTM) status and potentially influence A375 cell signaling irrespective of BRAFi resistance. Mass spectrometry (MS) measurements confirmed variant-driven PTM changes in 12 proteins. Among them was the runt-related transcription factor 1 (RUNX1) displaying a variant on a known phosphorylation site S(Ph)276L. We confirmed the loss of phosphorylation site by MS and demonstrated the impact of this variant on RUNX1 interactome.

Downregulation of inflammatory mediators by ethanolic extract of Bergenia ligulata (Wall.) in oxalate injured renal epithelial cells

ETHNOPHARMACOLOGICAL RELEVANCE

In the Indian traditional system of medicine, Bergenia ligulata (Wall.) Engl. has been used for treatment of urolithiasis. Its efficacious nature has led to its incorporation in various commercial herbal formulations such as Cystone and Neeri which are prescribed for kidney related ailments.

AIM OF THE STUDY

To assess whether ethanolic extract of B. ligulata can mitigate the cascade of inflammatory responses that cause oxidative stress and ultimately cell death in renal epithelial cells exposed to hyperoxaluric conditions.

MATERIAL AND METHODS

Bioactivity guided fractionation using solvents of varying polarities was employed to evaluate the potential of the extracts of B. ligulata to inhibit the crystallization process. Modulation of crystal morphology was visualized through Scanning electron microscopy (SEM) analysis. Cell death was assessed using flow cytometry based assays. Alteration in the inflammatory mediators was evaluated using real time PCR and immunocytochemistry. Phytochemical characterization of the ethanolic extract was carried out using FTIR, LC-MS and GC-MS.

RESULTS

Bioactivity guided fractionation for the assessment of antilithiatic activity revealed dose dependent inhibition of nucleation and aggregation process of calcium oxalate crystals in the presence of various extracts, however ethanolic extract showed maximum inhibition and was chosen for further experiments. Studies on renal epithelial NRK-52E cells showed, cytoprotective efficacy of B. ligulata extract against oxalate injury. SEM anaysis further revealed the potential of the extract to modulate the crystal structure and adhesion to renal cell surface. Exposure of the renal cells to the extract led to conversion of the calcium oxalate monohydrate (COM) crystals to the less injurious calcium oxalate dihydrate (COD) form. Expression analysis for oxidative stress and inflammatory biomarkers in NRK-52E cells revealed up-regulation of Mitogen activated protein kinase (MAPK), Osteopontin (OPN) and Nuclear factor- ĸB (NF-ĸB), in response to calcium oxalate insult; which was drastically reduced in the presence of B. ligulata extract. Flow cytometric evaluation pointed to caspase 3 mediated apoptotic cell death in oxalate injured cells, which was attenuated by B. ligulata extract.

CONCLUSION

Considering the complex multifactorial etiology of urolithiasis, ethanolic extract from B. ligulata can be a promising option for the management of kidney stones, as it has the potential to limit inflammation and the subsequent cell death.

The Aurora kinase/β-catenin axis contributes to dexamethasone resistance in leukemia

Glucocorticoids, such as dexamethasone and prednisolone, are widely used in cancer treatment. Different hematological malignancies respond differently to this treatment which, as could be expected, correlates with treatment outcome. In this study, we have used a glucocorticoid-induced gene signature to develop a deep learning model that can predict dexamethasone sensitivity. By combining gene expression data from cell lines and patients with acute lymphoblastic leukemia, we observed that the model is useful for the classification of patients. Predicted samples have been used to detect deregulated pathways that lead to dexamethasone resistance. Gene set enrichment analysis, peptide substrate-based kinase profiling assay, and western blot analysis identified Aurora kinase, S6K, p38, and β-catenin as key signaling proteins involved in dexamethasone resistance. Deep learning-enabled drug synergy prediction followed by in vitro drug synergy analysis identified kinase inhibitors against Aurora kinase, JAK, S6K, and mTOR that displayed synergy with dexamethasone. Combining pathway enrichment, kinase regulation, and kinase inhibition data, we propose that Aurora kinase or its several direct or indirect downstream kinase effectors such as mTOR, S6K, p38, and JAK may be involved in β-catenin stabilization through phosphorylation-dependent inactivation of GSK-3β. Collectively, our data suggest that activation of the Aurora kinase/β-catenin axis during dexamethasone treatment may contribute to cell survival signaling which is possibly maintained in patients who are resistant to dexamethasone.

Homoharringtonine inhibits melanoma cells proliferation in vitro and vivo by inducing DNA damage, apoptosis, and G2/M cell cycle arrest

Homoharringtonine (HHT), an approved anti-leukemic alkaloid, has been reported effectively in many types of tumor cells. However, its effect on melanoma cells has not been investigated. And the anti-melanoma mechanism of HHT is still unknown. In this study, we detected the effects of HHT on two melanoma cell lines (A375 and B16F10) and on the A375 xenograft mouse model. HHT significantly inhibited the proliferation of melanoma cells as investigated by the CCK8 method, cell cloning assay, and EdU experiment. HHT induced A375 and B16F10 cells DNA damage, apoptosis, and G2/M cell cycle arrest as proved by TdT-mediated dUTP Nick-End Labeling (TUNEL) and flow cytometry assay. Additionally, the loss of mitochondrial membrane potential in HHT-treated cells were visualized by JC-1 fluorescent staining. For the molecule mechanism study, western blotting results indicated the protein expression levels of ATM, P53, p-P53, p-CHK2, γ-H2AX, PARP, cleaved-PARP, cleaved caspase-3, cleaved caspase-9, Bcl-2, Bax, Aurka, p-Aurka, Plk1, p-Plk1, Cdc25c, CDK1, cyclin B1, and Myt1 were regulated by HHT. And the relative mRNA expression level of Aurka, Plk1, Cdc25c, CDK1, cyclin B1, and Myt1 were ascertained by q-PCR assay. The results in vivo experiment showed that HHT can slow down the growth rate of tumors. At the same time, the protein expression levels in vivo were consistent with that in vitro. Collectively, our study provided evidence that HHT could be considered an effective anti-melanoma agent by inducing DNA damage, apoptosis, and cell cycle arrest.

Screening a Prognosis-Related Target Gene in Patients with HER-2-Positive Breast Cancer by Bioinformatics Analysis

OBJECTIVE

The objective of the present study was to determine a target gene and explore the molecular mechanisms involved in the pathogenesis of HER-2-positive breast cancer.

METHODS

Three RNA expression profiles obtained from the Gene Expression Omnibus (GEO) and the Cancer Genome Atlas (TCGA) were used to identify differentially expressed genes (DEGs) using the R software. A protein-protein interaction network was then constructed, and hub genes were determined. Subsequently, the relationship between clinical parameters and hub genes was examined to screen for target genes. Next, DNA methylation and genomic alterations of the target gene were evaluated. To further explore potential molecular mechanisms, a functional enrichment analysis of genes coexpressed with the target gene was performed.

RESULTS

The differential expression analysis revealed 217 DEGs in HER-2-positive breast cancer samples compared to normal breast tissues. RRM2 was the only hub gene closely associated with lymphatic metastasis and the patients' prognosis. Additionally, RRM2 was found to be consistently amplified and negatively associated with the level of methylation. Functional enrichment analysis showed that the coexpressed genes were mainly involved in cell cycle regulation.

CONCLUSIONS

RRM2 was identified as a target gene associated with the initiation, progression, and prognosis of HER-2-positive breast cancer, which may be considered as a new biomarker and therapeutic target.

Mitotic Poisons in Research and Medicine

Cancer is one of the greatest challenges of the modern medicine. Although much effort has been made in the development of novel cancer therapeutics, it still remains one of the most common causes of human death in the world, mainly in low and middle-income countries. According to the World Health Organization (WHO), cancer treatment services are not available in more then 70% of low-income countries (90% of high-income countries have them available), and also approximately 70% of cancer deaths are reported in low-income countries. Various approaches on how to combat cancer diseases have since been described, targeting cell division being among them. The so-called mitotic poisons are one of the cornerstones in cancer therapies. The idea that cancer cells usually divide almost uncontrolled and far more rapidly than normal cells have led us to think about such compounds that would take advantage of this difference and target the division of such cells. Many groups of such compounds with different modes of action have been reported so far. In this review article, the main approaches on how to target cancer cell mitosis are described, involving microtubule inhibition, targeting aurora and polo-like kinases and kinesins inhibition. The main representatives of all groups of compounds are discussed and attention has also been paid to the presence and future of the clinical use of these compounds as well as their novel derivatives, reviewing the finished and ongoing clinical trials.

The role of Aurora-A in human cancers and future therapeutics

Aurora-A is a mitotic serine/threonine-protein kinase and an oncogene. In normal cells, Aurora-A appears from G2 phase and localizes at the centrosome, where it participates in centrosome replication, isolation and maturation. Aurora-A also maintains Golgi apparatus structure and spindle assembly. Aurora-A undergoes ubiquitination-mediated degradation after the cell division phase. Aurora-A is abnormally expressed in tumor cells and promotes cell proliferation by regulating mitotic substrates, such as PP1, PLK1, TPX2, and LAST2, and affects other molecules through a non-mitotic pathway to promote cell invasion and metastasis. Some molecules in tumor cells also indirectly act on Aurora-A to regulate tumor cells. Aurora-A also mediates resistance to chemotherapy and radiotherapy and is involved in tumor immunotherapy. Clinical trials of Aurora-A molecular inhibitors are currently underway, and clinical transformation is just around the corner.

Inhibition of Aurora Kinase A by Alisertib Reduces Cell Proliferation and Induces Apoptosis and Autophagy in HuH-6 Human Hepatoblastoma Cells

Purpose

Aurora kinase A (AURKA), which belongs to the serine/threonine protein kinase family, has been identified as a key driver of the genesis and progression of diverse tumors. The aim of this study was to determine the clinical significance of AURKA in patients with hepatoblastoma (HB) and the effect of inhibiting AURKA in the HB cell line HuH-6.

Methods

The expression of AURKA in HB tissue and adjacent normal liver tissue was detected by immunohistochemistry. Then, statistical analysis was performed to evaluate the association between AURKA expression and the clinicopathological characteristics of HB. The effect of AURKA knockdown on cell viability was assessed by CCK-8 assay. EdU and CCK-8 assays, Western blotting, flow cytometry, and transmission electron microscopy (TEM) were used to examine the effect of alisertib (ALS), a selective AURKA small-molecule inhibitor, on the cell cycle, proliferation, apoptosis, and autophagy in HuH-6 human hepatoblastoma cells.

Results

The expression of AURKA was significantly higher in HB tissue than in adjacent normal tissue. Furthermore, high AURKA expression was associated with advanced Children’s Oncology Group (COG) stage and tumor metastasis of HB. In vitro, AURKA knockdown significantly reduced the viability of HuH-6 cells, while ALS treatment significantly suppressed HuH-6 cell proliferation and induced G1-phase cell cycle arrest by reducing cyclin-D1 expression. Moreover, ALS promoted apoptosis and autophagy by decreasing the activity of p38 MAPK in HuH-6 cells.

Conclusion

High expression of AURKA is a potential predictor of poor prognosis in HB patients. AURKA knockdown reduced the viability of HuH-6 cells, and ALS treatment inhibited cell proliferation and induced apoptosis and autophagy via the p38 MAPK signaling pathway. Our results suggest that AURKA may be a novel therapeutic target and ALS a potential therapeutic drug for the treatment of HB.

Effects of Notch/p38MAPK signaling pathway on articular cartilage defect recovery by BMSCs tissue based on the rabbit articular cartilage defect models

Objective

The objective is to clarify the effects of Notch/p38MAPK signaling pathway on articular cartilage defect recovery by BMSCs tissue and provide a basis for clinical treatments of articular cartilage defects.

Methods

A total of 96 healthy male rabbits (weighed 1.5–2.0 kg) that were fully-grown were selected and grouped as the no-treatment group, the model group, and the treatment group in a random manner. Each group included 32 rabbits in total. The no-treatment group was fed without any interventions. The model group and the treatment group were constructed into rabbit knee-joint articular cartilage defect models. In addition, rabbits in the treatment group were given intervention treatments with Notch inhibitor (DAPT) combined with p38MAPK inhibitor (SB203580). The general conditions of rabbits in each group and the conditions of the stained articular cartilage tissue samples were observed, the proliferation of chondrocytes of rabbits in each group was compared.

Results

(1) After drug interventions, in contrast to the rabbits in the model group, the general conditions and the chondrocyte recovering situations of rabbits in the treatment group were obviously improved; (2) 8 weeks after model construction, the articular cartilage empty bone lacuna rate of rabbits in the treatment group was (12.13 ± 1.81)%, which was obviously lower than the synchronous (21.55 ± 3.07)% articular cartilage empty bone lacuna rate of rabbits in the model group, and there was a statistical significance in the differences (P < 0.05); (3) the absorbance value (OD value) of chondrocytes in the treatment group was (0.34 ± 0.015), which was obviously higher than the (0.10 ± 0.020) OD value of chondrocytes in the model group, and there was a statistical significance in the differences (P < 0.05).

Conclusion

The inhibition of Notch/p38MAPK signaling pathway can promote the recovery of articular cartilage by BMSCs tissue, accelerate the proliferation of chondrocytes, and contribute to the recovery of knee-joint injuries in rabbits, which provides a reliable basis for clinical treatments of articular cartilage defects.

GD2 ganglioside-binding antibody 14G2a and specific aurora A kinase inhibitor MK-5108 induce autophagy in IMR-32 neuroblastoma cells

The process of autophagy and its role in survival of human neuroblastoma cell cultures was studied upon addition of an anti-GD2 ganglioside (GD2) 14G2a mouse monoclonal antibody (14G2a mAb) and an aurora A kinase specific inhibitor, MK-5108. It was recently shown that combination of these agents significantly potentiates cytotoxicity against IMR-32 and CHP-134 neuroblastoma cells in vitro, as compared to the inhibitor used alone. In this study we gained mechanistic insights on autophagy in the observed cytotoxic effects exerted by both agents using cytotoxicity assays, RT-qPCR, immunoblotting, and autophagy detection methods. Enhancement of the autophagy process in the 14G2a mAb- and MK-5108-treated IMR-32 cells was documented by assessing autophagic flux. Application of a lysosomotropic agent-chloroquine (CQ) affected the 14G2a mAb- and MK-5108-stimulated autophagic flux. It is our conclusion that the 14G2a mAb (40 μg/ml) and MK-5108 inhibitor (0.1 μM) induce autophagy in IMR-32 cells. Moreover, the combinatorial treatment of IMR-32 cells with the 14G2a mAb and CQ significantly potentiates cytotoxic effect, as compared to CQ used alone. Most importantly, we showed that interfering with autophagy at its early and late step augments the 14G2a mAb-induced apoptosis, therefore we can conclude that inhibition of autophagy is the primary mechanism of the CQ-mediated sensitization to the 14G2a mAb-induced apoptosis. Although, there was no virtual stimulation of autophagy in the 14G2a mAb-treated CHP-134 neuroblastoma cells, we were able to show that PHLDA1 protein positively regulates autophagy and this process exists in a mutually exclusive manner with apoptosis in PHLDA1-silenced CHP-134 cells.

Autophagy, anoikis, ferroptosis, necroptosis, and endoplasmic reticulum stress: Potential applications in melanoma therapy

Melanoma as the most major skin malignancy has attracted much attention, so far. Although a successful therapeutic strategy requires an accurate understanding of the precise mechanisms for the initiation and progression of the melanoma. Several types of cell death mechanisms have recently been identified along with conventional cell death mechanisms such as apoptosis and necrosis. Among those mechanisms, necroptosis, anoikis, ferroptosis, and autophagy may be considered to have remarkable modulatory impacts on melanoma. In the present review, we explain the mechanisms of cell death signaling pathways related to autophagy, ferroptosis, anoikis, necroptosis, and reticulum endoplasmic stress in cells and describe how those mechanisms transduce signals in melanoma cells. Meanwhile, we describe how we can modulate those mechanisms to eliminate melanoma.

Porcine epidemic diarrhea virus infections induce apoptosis in Vero cells via a reactive oxygen species (ROS)/p53, but not p38 MAPK and SAPK/JNK signalling pathways

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p53 is activated, translocated to nucleus and involved in PEDV-induced apoptosis.

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ROS are accumulated during PEDV infection and involved in PEDV-induced apoptosis.

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ROS are the upper stream of p53 in PEDV infection.

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This is the first report that PEDV induce Vero cells apoptosis via ROS/p53 signal pathway.

Porcine epidemic diarrhea virus (PEDV) is a member of Coronavirus, which causes severe watery diarrhea in piglets with high morbidity and mortality. ROS and p53 play key roles in regulating many kinds of cell process during viral infection, however, the exact function in PEDV-induced apoptosis remains unclear. In this study, the pro-apoptotic effect of PEDV was examined in Vero cells and we observed that PEDV infection increased MDM2 and CBP, promoted p53 phosphorylation at serine 20 and, promoted p53 nuclear translocation, leading to p53 activation in Vero cells. Treatment with the p53 inhibitor PFT-α could significantly inhibit PEDV-induced apoptosis. We also observed PEDV infection induced time-dependent ROS accumulation. Treatment with antioxidants, such as pyrrolidine dithiocarbamate (PDTC) or N-acetylcysteine (NAC), significantly inhibited PEDV-induced apoptosis.

Moreover, further inhibition tests were established to prove that p53 was regulated by ROS in PEDV-induced apoptosis. In addition, we also found that p38 MAPK and SAPK/JNK were activated in PEDV-infected Vero cells. However, treatment with the p38 MAPK inhibitor SB203580, and the SAPK/JNK inhibitor SP600125 reversed PEDV-induced apoptosis. Taken together, the results of this study demonstrate that activated p53 and accumulated ROS participated in PEDV-induced apoptosis and p53 could be regulated by ROS during PEDV infection. Activated p38 MAPK and SAPK/JNK exerted no influence on PEDV-induced apoptosis. These findings provide new insights into the function of p53 and ROS in the interaction of PEDV with Vero cells.

Effects of miR‑103a‑3p on the autophagy and apoptosis of cardiomyocytes by regulating Atg5

Autophagy and apoptosis are associated with cardiovascular diseases. Emerging evidence shows that microRNAs (miRs) are critical in the development of pathological processes underlying cardiovascular diseases by regulating the induction of apoptosis and autophagy. The present study aimed to investigate the role of miR-103a-3p in cardiomyocyte injury through autophagy and apoptosis. H9c2 cells were cultured under hypoxia and reoxygenation (H/R) conditions and were used to mimic cells under ischemia. The transfection of cells with miR-103a-3p (mimics and inhibitors) was performed to examine its function in cardiomyocytes. The expression levels of miR-103a-3p were evaluated by reverse transcription-quantitative polymerase chain reaction analysis. Cell viability was determined using an MTT assay, and the lactate dehydrogenase assay (LDH) was used to investigate cell injury. The expression levels of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein, Beclin-1, autophagy-related 5 (Atg5), cleaved caspase-3 and cleaved caspase-9 were detected using western blotting. Immunofluorescence assays were performed to detect the expression of LC3 as a marker of autophagy. The target gene of miR-103a-3p was identified using dual-luciferase reporter assays. The results revealed that the expression levels of miR-103a-3p were significantly downregulated in cardiomyocytes under H/R conditions. Injury of the cardiomyocytes was evaluated under H/R conditions. Following transfection of the cells with miR-103a-3p inhibitors, cell injury was increased, as determined by LDH and MTT assays. The expression levels of apoptotic proteins were consistent with the results obtained in the LDH and cell viability assays. The induction of autophagy was increased in cells under H/R conditions and cells with miR-103a-3p inhibitor transfection, whereas the induction of autophagy was decreased in cells transfected with miR-103a-3p mimics. In addition, the data indicated that miR-103a-3p directly targeted Atg5, which regulated the induction of autophagy and apoptosis. Taken together, these findings indicate that, following the inhibition of miR-103a-3p, Atg5 promotes autophagy and apoptosis in cardiomyocytes by directly targeting Atg5. Therefore, miR-103a-3p can be considered a potential therapeutic target for myocardial ischemia.

Selective Autophagy Regulates Cell Cycle in Cancer Therapy

Aberrant function of cell cycle regulators results in uncontrolled cell proliferation, making them attractive therapeutic targets in cancer treatment. Indeed, survival of many cancers exclusively relies on these proteins, and several specific inhibitors are in clinical use. Although the ubiquitin-proteasome system is responsible for the periodic quality control of cell cycle proteins during cell cycle progression, increasing evidence clearly demonstrates the intimate interaction between cell cycle regulation and selective autophagy, important homeostasis maintenance machinery. However, these studies have often led to divergent rather than unifying explanations due to complexity of the autophagy signaling network, the inconsistent functions between general autophagy and selective autophagy, and the different characteristics of autophagic substrates. In this review, we highlight current data illustrating the contradictory and important role of cell cycle proteins in regulating autophagy. We also focus on how selective autophagy acts as a central mechanism to maintain orderly DNA repair and genome integrity by degrading specific cell cycle proteins, regulating cell division, and promoting DNA damage repair. We further discuss the ways in which selective autophagy may impact the cell cycle regulators, since failure to appropriately remove these can interfere with cell death-related processes, including senescence and autophagy-related cell death. Imbalanced cell proliferation is typically utilized by cancer cells to acquire resistance. Finally, we discuss the possibility of a potent anticancer therapeutic strategy that targets selective autophagy or autophagy and cell cycle together.