Overexpression of PTEN may increase the effect of pemetrexed on A549 cells via inhibition of the PI3K/AKT/mTOR pathway and carbohydrate metabolism

MiR-320a upregulation contributes to the effectiveness of pemetrexed by inhibiting the growth and invasion of human lung cancer cell line (Calu-6)

BACKGROUND

Lung cancer is a common and deadly disease. Chemotherapy is the most common treatment, which inhibits cancer cell growth. Pemetrexed (PMX) is often used with other drugs. Environmental stress can affect regulatory non-coding RNAs such as MicroRNAs that modify gene expression. This study investigates the effect of PMX on the hsa-miR-320a-3p expression in the Calu-6 lung cancer cell line.

METHODS AND RESULT

Calu-6 cells were cultured in an incubator with 37 °C, 5% CO2, and 98% humidity. The MTT test was performed to determine the concentration of PMX required to inhibit 50% of cell growth. To examine growth inhibition and apoptosis, release of lactate dehydrogenase (LDH), cell assays and caspase 3 and 7 enzyme activity were used. Finally, molecular studies were conducted to compare the expression of hsa-miR-320a-3p and genes including VDAC1, DHFR, STAT3, BAX and BCL2 before and after therapy.

RESULTS

According to a study, it has been observed that PMX therapy significantly increases LDH release after 24 h. The study found that PMX's IC50 on Calu-6 is 8.870 µM. In addition, the treated sample showed higher expression of hsa-miR-320a-3p and BAX, while the expression of VDAC1, STAT3, DHFR and BCL2 decreased compared to the control sample.

CONCLUSION

According to the findings of the current research, hsa-miR-320a-3p seems to have the potential to play an important role in the development of novel approaches to the treatment of lung cancer.

Targeting the "hallmarks of aging" to slow aging and treat age-related disease: fact or fiction?

Aging is a major risk factor for a number of chronic diseases, including neurodegenerative and cerebrovascular disorders. Aging processes have therefore been discussed as potential targets for the development of novel and broadly effective preventatives or therapeutics for age-related diseases, including those affecting the brain. Mechanisms thought to contribute to aging have been summarized under the term the "hallmarks of aging" and include a loss of proteostasis, mitochondrial dysfunction, altered nutrient sensing, telomere attrition, genomic instability, cellular senescence, stem cell exhaustion, epigenetic alterations and altered intercellular communication. We here examine key claims about the "hallmarks of aging". Our analysis reveals important weaknesses that preclude strong and definitive conclusions concerning a possible role of these processes in shaping organismal aging rate. Significant ambiguity arises from the overreliance on lifespan as a proxy marker for aging, the use of models with unclear relevance for organismal aging, and the use of study designs that do not allow to properly estimate intervention effects on aging rate. We also discuss future research directions that should be taken to clarify if and to what extent putative aging regulators do in fact interact with aging. These include multidimensional analytical frameworks as well as designs that facilitate the proper assessment of intervention effects on aging rate.

Reconstruction and Exploratory Analysis of mTORC1 Signaling Pathway and Its Applications to Various Diseases Using Network-Based Approach

Mammalian target of rapamycin (mTOR) is a serine-threonine kinase member of the cellular phosphatidylinositol 3-kinase (PI3K) pathway, which is involved in multiple biological functions by transcriptional and translational control. mTOR is a downstream mediator in the PI3K/Akt signaling pathway and plays a critical role in cell survival. In cancer, this pathway can be activated by membrane receptors, including the HER (or ErbB) family of growth factor receptors, the insulin-like growth factor receptor, and the estrogen receptor. In the present work, we congregated an electronic network of mTORC1 built on an assembly of data using natural language processing, consisting of 470 edges (activations/interactions and/or inhibitions) and 206 nodes representing genes/proteins, using the Cytoscape 3.6.0 editor and its plugins for analysis. The experimental design included the extraction of gene expression data related to five distinct types of cancers, namely, pancreatic ductal adenocarcinoma, hepatic cirrhosis, cervical cancer, glioblastoma, and anaplastic thyroid cancer from Gene Expression Omnibus (NCBI GEO) followed by pre-processing and normalization of the data using R & Bioconductor. ExprEssence plugin was used for network condensation to identify differentially expressed genes across the gene expression samples. Gene Ontology (GO) analysis was performed to find out the over-represented GO terms in the network. In addition, pathway enrichment and functional module analysis of the protein-protein interaction (PPI) network were also conducted. Our results indicated NOTCH1, NOTCH3, FLCN, SOD1, SOD2, NF1, and TLR4 as upregulated proteins in different cancer types highlighting their role in cancer progression. The MCODE analysis identified gene clusters for each cancer type with MYC, PCNA, PARP1, IDH1, FGF10, PTEN, and CCND1 as hub genes with high connectivity. MYC for cervical cancer, IDH1 for hepatic cirrhosis, MGMT for glioblastoma and CCND1 for anaplastic thyroid cancer were identified as genes with prognostic importance using survival analysis.

HER4 Promotes Osteosarcoma Progression and Predicts Poor Prognosis through the PTEN-PI3K/AKT Pathway

Studies have reported a relationship between human epidermal growth factor receptor 4 (HER4), a ubiquitously expressed and unique member of the ErbB family, and clinicopathological features of osteosarcoma. However, further investigation is warranted. HER4 expression was analyzed by quantitative reverse transcription-polymerase chain reaction, western blotting, and immunohistochemistry. The relationship between HER4 expression and the prognosis of patients with osteosarcoma was determined by constructing a Kaplan-Meier curve. Cell viability and proliferation were investigated by MTT and colony formation assays. The mechanism underlying HER4-modulated proliferation and invasion/migration of osteosarcoma cells was determined by short hairpin RNA (shRNA) interference, colony formation, migration, invasion, and western blotting experiments. Spheroid formation assay and CD133+ cell populations were used to examine HER4-induced stem-like traits.

The present findings revealed that HER4 was overexpressed in both osteosarcoma cells and tissues. Moreover, this overexpression was associated with high Enneking stage, metastasis, and recurrence. Sh-HER4 showed obviously suppressed cell viability, colony formation, and invasion/migration. In addition, knockdown of HER4 markedly attenuated the spheroid size and proportion of CD133-positive cells, as well as the expression of stemness markers. Sh-HER4 also reduced the tumor size, downregulated the expression of phosphorylated-PI3K (p-PI3K) and p-AKT, and increased that of p-phosphatase and tensin homolog (p-PTEN) in mouse tissue. From a mechanistic perspective, HER4 knockdown activated p-PTEN and suppressed p-PI3K and p-AKT expression. HER4 promoted osteosarcoma progression through inactivation of the PTEN-PI3K/AKT pathway.

Taken together, the results indicate that HER4 represents a novel target in osteosarcoma progression and stemness modulation, and may be of value for the development of treatments against osteosarcoma.

Taurine Alleviates Streptococcus uberis-Induced Inflammation by Activating Autophagy in Mammary Epithelial Cells

Streptococcus uberis infection can cause serious inflammation and damage to mammary epithelial cells and tissues that can be significantly alleviated by taurine. Autophagy plays an important role in regulating immunity and clearing invasive pathogens and may be regulated by taurine. However, the relationships between taurine, autophagy, and S. uberis infection remain unclear. Herein, we demonstrate that taurine augments PTEN activity and inhibits Akt/mTOR signaling, which decreases phosphorylation of ULK1 and ATG13 by mTOR and activates autophagy. Activating autophagy accelerates the degradation of intracellular S. uberis, reduces intracellular bacterial load, inhibits over-activation of the NF-κB pathway, and alleviates the inflammation and damage caused by S. uberis infection. This study increases our understanding of the mechanism through which taurine regulates autophagy and is the first to demonstrate the role of autophagy in S. uberis infected MAC-T cells. Our study also provides a theoretical basis for employing nutritional elements (taurine) to regulate innate immunity and control S. uberis infection. It also provides theoretical support for the development of prophylactic strategies for this important pathogen.

The Differential Effects of Propylthiouracil and Methimazole as Graves' Disease Treatment on Vascular Atherosclerosis Markers: A Randomized Clinical Trial

BACKGROUND

Hyperthyroidism is related to vascular atherosclerosis. Propylthiouracil (PTU) and methimazole, other than their antithyroid effects, may have different mechanisms in preventing atherogenesis in Graves' disease.

OBJECTIVE

This study aimed to investigate the effect of antithyroid drugs on markers of vascular atherosclerosis in Graves' hyperthyroidism.

METHODS

This study was a single-blind, randomized clinical trial conducted on 36 patients with Graves' disease in Cipto Mangunkusumo General Hospital, Jakarta, Indonesia, from June 2019 until July 2020. Graves' disease was diagnosed from clinical manifestation of hyperthyroidism with diffuse goiter and then confirmed by thyroid stimulation hormone (TSH), free T4 (fT4), and TSH-receptor antibody (TRAb) measurements. Participants were randomly assigned to either a PTU or a methimazole treatment group and followed up for 3 months. Markers of vascular atherosclerosis were represented by adhesion molecules [intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin], carotid artery stiffness [pulse wave velocity (PWV)], and thickness [carotid intima media thickness (cIMT)].

RESULTS

By the end of the study, 24 participants reached euthyroid condition (13 from the PTU group and 11 from the methimazole group). After 3 months of follow-up, in the PTU group, we noticed an improvement of ICAM-1 [pretreatment: 204.1 (61.3) vs. posttreatment: 141.6 (58.4) ng/ml; p = 0.001], VCAM-1 [837 (707-977) vs. 510 (402-630) ng/ml; p < 0.001] and E-selectin [32.1 (24.1-42.7) vs. 28.2 (21.6-36.8) ng/ml; p = 0.045] in the PTU group. In the methimazole group, only VCAM-1 improvement [725 (565-904) vs. 472 (367-590); p = 0.001] was observed. Meanwhile, we found no significant changes in PWV or cIMT in either group.

CONCLUSION

Antithyroid treatment in Graves' disease leads to improvement in adhesion molecules, with a lesser effect on methimazole, whereas there were no significant changes in PWV or cIMT. PTU may have a better mechanism compared with methimazole in terms of improving adhesion molecules.

METTL3-mediated maturation of miR-126-5p promotes ovarian cancer progression via PTEN-mediated PI3K/Akt/mTOR pathway

Methyltransferase-like 3 (METTL3) functions as an RNA methyltransferase that controls the modification of N(6)-methyladenosine (m6A) to influence the biosynthesis, decay, and translation of mRNAs. This study aims to investigate the regulation of METTL3-mediated promotion of microRNA-126-5p (miR-126-5p) in the progression of ovarian cancer and to identify the mechanisms in relation to phosphatase and tensin homolog (PTEN) and the PI3K/Akt/mTOR pathway. We found high expression of miR-126-5p in ovarian cancer samples compared to paired adjacent samples, and also in ovarian cancer cell lines. Gain-of-function experiments demonstrated that overexpression of miR-126-5p promoted ovarian cancer cell proliferation, migration, and invasion, and inhibited their apoptosis. Luciferase reporter assay identified that miR-126-5p could directly bind to PTEN. By targeting PTEN, miR-126-5p could activate the PI3K/Akt/mTOR pathway. Furthermore, the RNA methyltransferase METTL3 promoted the maturation of miR-126-5p via the m6A modification of pri-miR-126-5p. Finally, in vitro and in vivo experiments substantiated that silencing of METTL3 impeded the progression and tumorigenesis of ovarian cancer by impairing the miR-126-5p-targeted inhibition of PTEN and thus blocking the PI3K/Akt/mTOR pathway. Coherently, knockdown of METTL3 inhibited the effect of miR-126-5p to upregulate PTEN, and thus prevents PI3K/Akt/mTOR pathway activation, thereby suppressing the development of ovarian cancer. These findings highlight potential targets for the future ovarian cancer treatment as well as tumorigenic mechanisms mediated by m6A modification.

PTEN Alterations and Their Role in Cancer Management: Are We Making Headway on Precision Medicine?

Alterations in the tumor suppressor phosphatase and tensin homolog (PTEN) occur in a substantial proportion of solid tumors. These events drive tumorigenesis and tumor progression. Given its central role as a downregulator of the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway, PTEN is deeply involved in cell growth, proliferation, and survival. This gene is also implicated in the modulation of the DNA damage response and in tumor immune microenvironment modeling. Despite the actionability of PTEN alterations, their role as biomarkers remains controversial in clinical practice. To date, there is still a substantial lack of validated guidelines and/or recommendations for PTEN testing. Here, we provide an update on the current state of knowledge on biologic and genetic alterations of PTEN across the most frequent solid tumors, as well as on their actual and/or possible clinical applications. We focus on possible tailored schemes for cancer patients' clinical management, including risk assessment, diagnosis, prognostication, and treatment.