Investigation and Characterization of the RAS/RAF/MEK/ERK Pathway and Other Signaling Pathways in Chronic Sinusitis with Nasal Polyps.

BACKGROUND: The clinical outcomes of drug treatments and surgical interventions for chronic sinusitis with nasal polyps (CRSwNPs) are suboptimal, and the high recurrence rate remains a significant challenge in clinical practice. Targeted therapies such as biologics provide new perspectives and directions for treating CRSwNP. SUMMARY: With the continuous investigation of signaling pathways, RAS/RAF/MEK/ERK signaling pathway and other signaling pathways including Hippo, JAK-STAT, Wnt, TGF-ß, PI3K, Notch, and NF-κB were confirmed to play an important role in the progression of CRSwNP. Among them, the abnormality of RAS/RAF/MEK/ERK signaling pathway is accompanied by the abnormality of this apoptotic component, which may provide new research directions for targeting the components of signaling pathways to mediate apoptosis. KEY MESSAGES: Abnormalities in signaling pathways are particularly important in studying the pathogenesis and treatment of CRSwNP. Therefore, this review summarizes the ongoing investigation and characterization of RAS/RAF/MEK/ERK signaling pathway and other signaling pathways in CRSwNP, which provides constructive ideas and directions for improving the treatment of CRSwNP.

TCF19 promotes cell proliferation and tumor formation in lung cancer by activating the Raf/MEK/ERK signaling pathway.

OBJECTIVE: This study aimed to investigate TCF19's role in lung cancer development, specifically its involvement in the RAF/MEK/ERK signaling pathway. METHODS: Lung cancer tissue analysis revealed significant TCF19 overexpression. In vitro experiments using A549 and Hop62 cells with TCF19 overexpression demonstrated enhanced cell growth. Transgenic mouse models confirmed TCF19's role in primary tumor development. Transcriptome sequencing identified altered gene expression profiles, linking TCF19 to RAF/MEK/ERK pathway activation. Functional assays elucidated underlying mechanisms, revealing increased phosphorylation of Raf1, MEK1/2, and ERK1/2. Inhibiting RAF1 or ERK through shRaf1 or ERK inhibitor reduced cell cycle-related proteins and inhibited TCF19-overexpressing cell growth. RESULTS: TCF19 was identified as an oncogene in lung carcinoma, specifically impacting the RAF/MEK/ERK pathway. Elevated TCF19 levels in lung cancer suggest targeting TCF19 or its associated pathways as a promising strategy for disease management. CONCLUSION: This study unveils TCF19's oncogenic role in lung cancer, emphasizing its modulation of the RAF/MEK/ERK pathway and presenting a potential therapeutic target for TCF19-overexpressing lung cancers.

Huanglian Jiedu decoction alleviates neurobehavioral damage in mice with chronic alcohol exposure through the RAS-RAF-MEK-ERK pathway.

Objective: Long-term alcohol consumption can cause organic damage to the brain, resulting in mental and nervous system abnormalities and intellectual impairment. Huanglian Jiedu decoction (HLJDD) is the classic representative of clearing heat and detoxifying. This study aimed to explore the effects and possible mechanisms of HLJDD on brain injury in chronic alcohol-exposed mice. Methods: The alcohol-exposed mice were treated with different doses of HLJDD to observe behavioral changes, hippocampal Aß1-42 deposition, number and ultrastructural changes of neurons in the hippocampus and prefrontal cortex, and expressions of synaptic proteins. On this basis, transcriptome sequencing was used to analyze the differentially expressed genes in different treatment groups, and functional enrichment analysis was performed. Then, WB and RT-PCR were used to verify the expression of the pathway. Results: Chronic alcohol exposure reduced body weight in mice, led to motor cognitive impairment, increased Aß1-42 in the hippocampus, decreased the number of neurons in the hippocampus and prefrontal cortex, and the expression of PSD95 and SYN in the hippocampus. HLJDD significantly improved the cognitive dysfunction of mice and alleviated the damage of the hippocampus and prefrontal cortex. Transcriptome sequencing results showed that the regulatory effects of HLJDD on chronic alcohol-exposed mice may be related to the RAS pathway. Further experiments confirmed that chronic alcohol exposure caused a significant increase in protein and gene expressions of the RAS-RAF-MEK-ERK pathway in mouse, and this activation was reversed by HLJDD. Conclusion: HLJDD may ameliorate brain damage caused by chronic alcohol exposure by regulating the RAS-RAF-MEK-ERK pathway.

CRKL but not CRKII contributes to hemin-induced erythroid differentiation of CML.

Destruction of erythropoiesis process leads to various diseases, including thrombocytopenia, anaemia, and leukaemia. miR-429-CT10 regulation of kinase-like (CRKL) axis involved in development, progression and metastasis of cancers. However, the exact role of miR-429-CRKL axis in leukaemic cell differentiation are still unknown. The current work aimed to uncover the effect of miR-429-CRKL axis on erythropoiesis. In the present study, CRKL upregulation was negatively correlated with miR-429 downregulation in both chronic myeloid leukaemia (CML) patient and CR patient samples. Moreover, CRKL expression level was significantly decreased while miR-429 expression level was increased during the erythroid differentiation of K562 cells following hemin treatment. Functional investigations revealed that overexpression and knockdown of CRKL was remarkably effective in suppressing and promoting hemin-induced erythroid differentiation of K562 cells, whereas, miR-429 exhibited opposite effects to CRKL. Mechanistically, miR-429 regulates erythroid differentiation of K562 cells by downregulating CRKL via selectively targeting CRKL-3'-untranslated region (UTR) through Raf/MEK/ERK pathway. Conversely, CRKII had no effect on erythroid differentiation of K562 cells. Taken together, our data demonstrated that CRKL (but not CRKII) and miR-429 contribute to development, progression and erythropoiesis of CML, miR-429-CRKL axis regulates erythropoiesis of K562 cells via Raf/MEK/ERK pathway, providing novel insights into effective diagnosis and therapy for CML patients.

Inhibition of the RAF/MEK/ERK Signaling Cascade in Pancreatic Cancer: Recent Advances and Future Perspectives.

Pancreatic cancer represents a formidable challenge in oncology, primarily due to its aggressive nature and limited therapeutic options. The prognosis of patients with pancreatic ductal adenocarcinoma (PDAC), the main form of pancreatic cancer, remains disappointingly poor with a 5-year overall survival of only 5%. Almost 95% of PDAC patients harbor Kirsten rat sarcoma virus (KRAS) oncogenic mutations. KRAS activates downstream intracellular pathways, most notably the rapidly accelerated fibrosarcoma (RAF)/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling axis. Dysregulation of the RAF/MEK/ERK pathway is a crucial feature of pancreatic cancer and therefore its main components, RAF, MEK and ERK kinases, have been targeted pharmacologically, largely by small-molecule inhibitors. The recent advances in the development of inhibitors not only directly targeting the RAF/MEK/ERK pathway but also indirectly through inhibition of its regulators, such as Src homology-containing protein tyrosine phosphatase 2 (SHP2) and Son of sevenless homolog 1 (SOS1), provide new therapeutic opportunities. Moreover, the discovery of allele-specific small-molecule inhibitors against mutant KRAS variants has brought excitement for successful innovations in the battle against pancreatic cancer. Herein, we review the recent advances in targeted therapy and combinatorial strategies with focus on the current preclinical and clinical approaches, providing critical insight, underscoring the potential of these efforts and supporting their promise to improve the lives of patients with PDAC.

miR-451a suppresses the proliferation and migration of high-grade serous ovarian cancer by targeting RAB5A through the Ras/Raf/MEK/ERK pathway.

BACKGROUND: Ovarian cancer is one of the most common cancers in women. Profiles changes of microRNAs (miRNAs) are closely linked to malignant tumors. In the present study, we investigated expression of miR-451a in high-grade serous ovarian cancer (HGSOC). We also investigated the potential pathological roles and the likely mechanism of miR-451a in the development of HGSOC using animal models and cell lines. METHODS: Using bioinformatics techniques and a real-time PCR, we analyzed differently expressed miRNAs in HGSOC compared to normal tissue. MTT (i.e. 3-[4, 5-dimethyl thiazol-2-yl]-2,5-diphenyl tetrazolium bromide), EDU (i.e. 5-ethynyl-2'-deoxyuridine) and transwell assays were performed to investigate the effect of miR-451a on the proliferation and migration of HGSOC SKOV-3 cells. A dual luciferase reporter assay was performed to verify the targeting relationship of miR-451 and RAB5A (one of the Rab GTPase proteins that regulates endocytosis and vesicle transport). Also, we analyzed levels of the RAB5A mRNA and protein by real-time PCR, western blotting and immunohistochemistry assays in HGSOC cells and tissues. Finally, we performed in vivo experiments using HGSOC mice. RESULTS: miR-451a was substantially upregulated in HGSOC and associated with favorable clinical characteristics. miR-451a knockdown significantly increased growth and metastasis of HGSOC cell line SKOV-3 through Ras/Raf/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling. In addition, RAB5A, an early endosome marker, was shown to be a direct target of miR-451a. Moreover, RAB5A is correlated with unfavorable clinical features and shows independent prognostic significance in HGSOC. CONCLUSIONS: We found that the miR-451a/RAB5A axis is associated with tumorigenesis and progression through the Ras/Raf/MEK/ERK pathway, providing prognostic indicators and therapeutic targets for patients with HGSOC.

The Role of Activation of PI3K/AKT/mTOR and RAF/MEK/ERK Pathways in Aggressive Pituitary Adenomas-New Potential Therapeutic Approach-A Systematic Review.

Pituitary tumors (PT) are mostly benign, although occasionally they demonstrate aggressive behavior, invasion of surrounding tissues, rapid growth, resistance to conventional treatments, and multiple recurrences. The pathogenesis of PT is still not fully understood, and the factors responsible for its invasiveness, aggressiveness, and potential for metastasis are unknown. RAF/MEK/ERK and mTOR signaling are significant pathways in the regulation of cell growth, proliferation, and survival, its importance in tumorigenesis has been highlighted. The aim of our review is to determine the role of the activation of PI3K/AKT/mTOR and RAF/MEK/ERK pathways in the pathogenesis of pituitary tumors. Additionally, we evaluate their potential in a new therapeutic approach to provide alternative therapies and improved outcomes for patients with aggressive pituitary tumors that do not respond to standard treatment. We perform a systematic literature search using the PubMed, Embase, and Scopus databases (search date was 2012-2023). Out of the 529 screened studies, 13 met the inclusion criteria, 7 related to the PI3K/AKT/mTOR pathway, and 7 to the RAF/MEK/ERK pathway (one study was used in both analyses). Understanding the specific factors involved in PT tumorigenesis provides opportunities for targeted therapies. We also review the possible new targeted therapies and the use of mTOR inhibitors and TKI in PT management. Although the RAF/MEK/ERK and PI3K/AKT/mTOR pathways play a pivotal role in the complex signaling network along with many interactions, further research is urgently needed to clarify the exact functions and the underlying mechanisms of these signaling pathways in the pathogenesis of pituitary adenomas and their role in its invasiveness and aggressive clinical outcome.

Direct-Current Electrical Field Stimulation of Patient-Derived Colorectal Cancer Cells.

Several cues for a directional migration of colorectal cancer cells were identified as being crucial in tumor progression. However, galvanotaxis, the directional migration in direct-current electrical fields, has not been investigated so far. Therefore, we asked whether direct-current electrical fields could be used to mobilize colorectal cancer cells along field vectors. For this purpose, five patient-derived low-passage cell lines were exposed to field strengths of 150-250 V/m in vitro, and migration along the field vectors was investigated. To further study the role of voltage-gated calcium channels on galvanotaxis and intracellular signaling pathways that are associated with migration of colorectal cancer cells, the cultures were exposed to selective inhibitors. In three out of five colorectal cancer cell lines, we found a preferred cathodal migration. The cellular integrity of the cells was not impaired by exposure of the cells to the selected field strengths. Galvanotaxis was sensitive to inhibition of voltage-gated calcium channels. Furthermore, signaling pathways such as AKT and MEK, but not STAT3, were also found to contribute to galvanotaxis in our in vitro model system. Overall, we identify electrical fields as an important contributor to the directional migration of colorectal cancer cells.

Smilax glabra Roxb. flavonoids protect against pathological cardiac hypertrophy by inhibiting the Raf/MEK/ERK pathway: In vivo and in vitro studies.

ETHNOPHARMACOLOGICAL RELEVANCE: Smilax glabra Roxb., the dry rhizome of Sarsaparilla, which is also known as Tu fuling (TFL) in China, is a well-known traditional CHINESE medicine that is widely used for detoxication, relieving dampness and as a diuretic. We have previously shown that the extracted TFL flavonoids (designated TFLF) possess anti-cardiac hypertrophy effects in vitro. However, the anti-cardiac hypertrophy effects of TFLF in vivo and the underlying mechanisms remain to be elucidated. AIM OF THE STUDY: To reveal the underlying therapeutic mechanism of TFLF on cardiac hypertrophy by using transverse aortic constriction (TAC) model and cellular assays in vitro. MATERIAL & METHODS: Cardiac hypertrophy was replicated by TAC surgery in rats or by isoprenaline treatment of rat H9C2 myocardial cells in vitro. Cardiac structure and function were evaluated by echocardiographic and hemodynamic examinations in vivo and histological analysis of tissues ex vivo. Biochemical kits and quantitative PCR were used to analyze markers of cardiac hypertrophy. Expression and phosphorylation of key proteins in the Raf/MEK/ERK pathway were quantified by Western blotting. We further confirmed our findings in H9C2 rat cardiomyocytes treated with isoprenaline and the ERK inhibitor in vitro. RESULTS: TFLF attenuated cardiac hypertrophy and fibrosis and improved cardiac dysfunction in TAC rats. TFLF treatment induced a strong reduction in serum NT-proBNP levels. Cardiac hypertrophy marker gene (ANP, BNP and ß-MHC) expression and the phosphorylation levels of c-Raf and ERK1/2 were decreased by TFLF treatment. TFLF also protected H9C2 cells from isoprenaline-induced hypertrophy in vitro via a similar molecular mechanism as that observed in the rat heart. Moreover, pretreatment with TRLF and the ERK inhibitor further inhibited the mRNA overexpression of hypertrophic genes in vitro. CONCLUSIONS: TFLFs may protect against pathological cardiac hypertrophy via negative regulation of the Raf/MEK/ERK pathway. Thus, TFLFs are implicated as a potential pharmacological agent for treating cardiac hypertrophy in clinical practice.

BLU-554, A selective inhibitor of FGFR4, exhibits anti-tumour activity against gastric cancer in vitro.

BACKGROUND: Fibroblast growth factor receptor 4 (FGFR4) plays a key role in cancer progression, including tumour proliferation, invasion, and metastasis. Recent studies have shown that the FGFR4 selective inhibitor BLU-554 has clinical benefits on tumour regression in hepatocellular carcinoma patients. However, the effect of BLU-554 on gastric cancer remains unknown. METHODS: Changes in cell proliferation, apoptosis and cell cycle, migration, and invasion capabilities of MKN-45 cells treated with FGFR4 selective inhibitors were detected by CCK-8 assay, flow cytometry, transwell assay, and wound healing assay, respectively. Western blotting was used to detect the effect of BLU-554 on the expression of FGFR4, FRS2α, and p-ERK1/2. RESULTS: As the concentration of the inhibitor increased, the survival rate of gastric cancer cells decreased, and the trend of BLU-554 was more obvious; a high dose of BLU-554 caused significant cell apoptosis and cell cycle arrest as well as reduced cell invasion ability. The expression levels of FGFR4, FRS2α, and p-ERK1/2 were also significantly reduced when cells were treated with medium and high doses of BLU-554. CONCLUSION: BLU-554 inhibited the mitogen-activated protein kinase (RAS-RAF-MEK-ERK) pathway by inhibiting FGFR4, ultimately impeding the proliferation and invasion of gastric cancer cells and promoting cell apoptosis and cell cycle arrest.

METTL3 induces PLX4032 resistance in melanoma by promoting m6A-dependent EGFR translation.

Acquired resistance often limits therapeutic efficacy of the BFAF (V600E) kinase inhibitor PLX4032 in patients with advanced melanoma. Epitranscriptomic modification of mRNAs by N6-methyladenosine (m6A) modification contributes to melanoma pathogenesis; however, its role in acquired PLX4032 resistance remains unexplored. Here, we showed that m6A methyltransferase METTL3 expression is upregulated in A375R cells, a PLX4032-resistant subline of A375 melanoma cells, compared with the parental cells. Moreover, METTL3 increased the m6A modification of epidermal growth factor receptor (EGFR) mRNA in A375R cells, which promoted its translation efficiency. In turn, increased EGFR expression facilitated rebound activation of the RAF/MEK/ERK pathway in A375R cells, inducing PLX4032 resistance. In contrast, knockout of METTL3 in A375R cells reduced EGFR expression and restored PLX4032 sensitivity. PLX4032 treatment following METTL3 knockout induced apoptosis and reduced colony formation in A375R cells and reduced A375R cell-derived tumor growth in BALB/c nude mice. These findings indicate that METTL3 promotes rebound activation of the RAF/MEK/ERK pathway through EGFR upregulation and highlight a critical role for METTL3-induced m6A modification in acquired PLX4032 resistance in melanoma, implicating METTL3 as a potential candidate for targeted chemotherapy.

Pathway-Directed Therapy in Multiple Myeloma.

Multiple Myeloma (MM) is a malignant plasma cell disorder with an unmet medical need, in particular for relapsed and refractory patients. Molecules within deregulated signaling pathways, including the RAS/RAF/MEK/ERK, but also the PI3K/AKT-pathway belong to the most promising evolving therapeutic targets. Rationally derived compounds hold great therapeutic promise to target tumor-specific abnormalities rather than general MM-associated vulnerabilities. This paradigm is probably best depicted by targeting mutated BRAF: while well-tolerated, remarkable responses have been achieved in selected patients by inhibition of BRAFV600E alone or in combination with MEK. Targeting of AKT has also shown promising results in a subset of patients as monotherapy or to resensitize MM-cells to conventional treatment. Approaches to target transcription factors, convergence points of signaling cascades such as p53 or c-MYC, are emerging as yet another exciting strategy for pathway-directed therapy. Informed by our increasing knowledge on the impact of signaling pathways in MM pathophysiology, rationally derived Precision-Medicine trials are ongoing. Their results are likely to once more fundamentally change treatment strategies in MM.

A Potential Tumor Suppressor Gene Named miR-508-5p Inhibited the Proliferation and Invasion of Human Melanoma Cells by Targeting KIT.

Melanoma is the main death cause of human skin cancer. Increasing evidences demonstrate that microRNAs act as key roles in mediating tumor occurrence and progression. MiR-508-5p has proved to participate in the development of various types of human malignancies. However, the role of miR-508-5p in melanoma remained unclear. In in vitro study, miR-508-5p level in peripheral blood samples of patients with melanoma and human melanoma A375 cells was downregulated compared to that in normal peripheral blood samples or normal human epidermal melanocytes (MHEM). MiR-508-5p overexpression significantly inhibited the cell proliferation, migration and invasion in A375 cells, and thus inhibiting KIT expression at both gene and protein levels. Furthermore, western blot analysis showed miR-508-5p reduced cell proliferation by targeting KIT to modulate RAS/RAF/MEK/ERK pathway. Taken together, we speculated that miR-508-5p functioned as an important suppressor in human melanoma by targeting KIT, suggesting miR-508-5p might be a promising tumor suppressor gene for further target therapies from bench to clinic.

Dissecting the mechanism of signaling-triggered nuclear export of newly synthesized influenza virus ribonucleoprotein complexes.

Influenza viruses (IV) exploit a variety of signaling pathways. Previous studies showed that the rapidly accelerated fibrosarcoma/mitogen-activated protein kinase/extracellular signal-regulated kinase (Raf/MEK/ERK) pathway is functionally linked to nuclear export of viral ribonucleoprotein (vRNP) complexes, suggesting that vRNP export is a signaling-induced event. However, the underlying mechanism remained completely enigmatic. Here we have dissected the unknown molecular steps of signaling-driven vRNP export. We identified kinases RSK1/2 as downstream targets of virus-activated ERK signaling. While RSK2 displays an antiviral role, we demonstrate a virus-supportive function of RSK1, migrating to the nucleus to phosphorylate nucleoprotein (NP), the major constituent of vRNPs. This drives association with viral matrix protein 1 (M1) at the chromatin, important for vRNP export. Inhibition or knockdown of MEK, ERK or RSK1 caused impaired vRNP export and reduced progeny virus titers. This work not only expedites the development of anti-influenza strategies, but in addition demonstrates converse actions of different RSK isoforms.

Genetic variants in Ras/Raf/MEK/ERK pathway are associated with gastric cancer risk in Chinese Han population.

The dysregulation of Ras/Raf/MEK/ERK pathway governs occurrence and progression of cancers. In previous studies, genome-wide association studies (GWAS) have identified multiple gene loci related to gastric cancer. However, a great many genetic loci have been missed due to multiple statistical comparisons of GWAS. In this study, Multi-marker Analysis of GenoMic Annotation (MAGMA) was applied to analyze genes in Ras/Raf/MEK/ERK pathway and their single nucleotide polymorphisms (SNPs) based on Chinese GWAS including 1625 gastric cancer cases and 2100 controls. The SNP effects on gastric cancer susceptibility were calculated on the basis of a logistic regression model. Expression quantitative trait loci (eQTL) analysis was performed based on the genotype-tissue expression (GTEx) project. We identified that three SNPs in MAP2K1, rs4287513, rs76906202 and rs11631448 were markedly associated with gastric cancer risk (rs4287513: OR = 1.30, 95% CI = 1.10-1.54, P = 1.92 × 10-3; rs76906202: OR = 0.87, 95% CI = 0.79-0.96, P = 3.72 × 10-3; rs11631448: OR = 1.21, 95% CI = 1.05-1.39, P = 6.74 × 10-3). All the loci were eQTLs for MAP2K1 in normal gastric samples. Moreover, the low expression of MAP2K1 was significantly associated with poor survival in gastric cancer patients. Thus, MAP2K1 might represent a key gene related to gastric cancer in Ras/Raf/MEK/ERK pathway, whereas SNPs in MAP2K1 confer gastric cancer susceptibility by having biological effects on the MAP2K1 expression.

Silencing circular RNA-ZNF652 represses proliferation and EMT process of renal carcinoma cells via raising miR-205.

Recently, the functions of circular RNAs (circRNAs) on cancer initiation and development arouse wide concern. Herein, we tested the influences of circ-ZNF652 on renal carcinoma cell growth and metastasis. Firstly, clinical renal carcinoma tissues and corresponding normal tissues were collected. The circ-ZNF652 expressions were tested. Then, the influences of silencing circ-ZNF652 on renal carcinoma A498 and ACHN cell proliferation, apoptosis and epithelial-mesenchymal transition (EMT) process, as well as Ras/Raf/MEK/ERK and JAK1/STAT3 pathways, were probed. Finally, whether miR-205 engaged in the influences of silencing circ-ZNF652 on A498 and ACHN cell were investigated. circ-ZNF652 had high expression level in clinical renal carcinoma tissues. Silencing circ-ZNF652 repressed A498 and ACHN cell proliferation and EMT process, but promoted cell apoptosis. Moreover, silencing circ-ZNF652 suppressed Ras/Raf/MEK/ERK and JAK1/STAT3 pathways in A498 and ACHN cells. Besides, the miR-205 expressions in A498 and ACHN cells were raised by silencing circ-ZNF652. Knockdown of miR-205 weakened the influences of silencing circ-ZNF652 on A498 and ACHN cell proliferation, apoptosis and EMT process. Silencing circ-ZNF652 repressed proliferation and EMT process of renal carcinoma A498 and ACHN cells via suppressing Ras/Raf/MEK/ERK and JAK1/STAT3 pathways, as well as raising miR-205 expression.

Single high dose irradiation induces cell cycle arrest and apoptosis in human hepatocellular carcinoma cells through the Ras/Raf/MEK/ERK pathways.

Purpose: Stereotactic body radiation therapy (SBRT) is emerging as a new noninvasive treatment in patients with primary liver carcinoma or liver-confined metastatic cancer. However, the radiobiological targets remain a subject of debate. Here, we investigated the potential biological effects of the radiation on the human hepatocellular carcinoma HepG2 cells.Materials and methods: Firstly, HepG2 cells were divided into three groups: control group, 3.5 Gy*8f group (L group), and 15 Gy*1f group (H group). After treatment, cell proliferation was examined using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide and plate colony formation assays. Cell cycle and apoptosis were assessed using propidium iodide and Hoechst 33258 staining, respectively. Furthermore, the mechanisms underlying irradiation-induced cell cycle arrest and cell apoptosis were investigated by Western blot assay.Results: Irradiation could effectively inhibit the proliferation and colony formation of HepG2 cells, and the single high dose irradiation showed stronger inhibitory effects. Irradiation-induced cell cycle arrest at G2/M phase in HepG2 cell, during which the expression levels of cyclin B1, CDK1, and p-CDK1 proteins were downregulated, whereas expression of p21 was upregulated in the irradiated HepG2 cells. After irradiation, typical morphological changes of apoptosis in HepG2 cells were observed; the number of cell apoptosis and the expression of apoptosis associated proteins were significantly increased in HepG2 cells by high dose irradiation compared with low dose irradiation. Additionally, compared with low dose irradiation, high dose irradiation significantly downregulated the phosphorylated proteins in the Ras/Raf/MEK/ERK signaling pathway.Conclusions: Our results suggest that irradiation applied in SBRT, particularly single high dose irradiation, mediates its anti-tumor effects by inducing cell cycle arrest and apoptosis via modulation of the Ras/Raf/MEK/ERK signaling pathway.

Geniposide exhibits anticancer activity to medulloblastoma cells by downregulating microRNA-373.

BACKGROUND: Medulloblastoma is a common tumor originates from central nervous system in children with metastatic potential. Geniposide is the major active ingredient separated from the fruit of Gardenia jasminoides Ellis. Herein, we tested the possible anticancer activity of geniposide on human medulloblastoma cells, as well as the potential underlying molecular mechanisms. METHODS: Firstly, followed by geniposide incubation, cell viability, proliferation, apoptosis, migration, and invasion of medulloblastoma Daoy cells, along with microRNA-373 (miR-373) expression were tested, respectively. Then, the influences of miR-373 overexpression in the reduction of medulloblastoma cell proliferation, migration, and invasion and the elevation of apoptosis, triggered by geniposide treatment, were re-investigated. Finally, the Ras/Raf/MEK/ERK pathway activity was analyzed. RESULTS: Geniposide treatment inhibited medulloblastoma cell viability, proliferation, migration, and invasion, but promoted cell apoptosis. Surprisingly, miR-373 expression in medulloblastoma cells was obviously downregulated by geniposide treatment. miR-373 overexpression reversed the effects of geniposide on Daoy cells. Furthermore, geniposide hindered the Ras/Raf/MEK/ERK pathway by downregulating miR-373 expression. CONCLUSION: Geniposide exhibited anticancer activity on human medulloblastoma cells and blocked Ras/Raf/MEK/ERK pathway by downregulating miR-373 expression.

RCE­4, a potential anti­cervical cancer drug isolated from Reineckia carnea, induces autophagy via the dual blockade of PI3K and ERK pathways in cervical cancer CaSki cells.

The steroidal saponin RCE­4 (1ß, 3ß, 5ß, 25S)­spirostan­1, 3­diol 1­[α­L­rhamnopyranosyl­(1→2)­ß­D­xylopyranoside], isolated from Reineckia carnea, exerts significant anti­cervical cancer activity by inducing apoptosis. The potential effect of RCE­4 on proliferation inhibition and autophagy induction has rarely been studied. Therefore, the focus of the present study was to investigate the effects of RCE­4 on proliferation, and to elucidate the detailed mechanisms involved in autophagy induction in cervical cancer cells. CaSki cells were treated with RCE­4 or/and autophagy inhibitors, and the effect of RCE­4 on cellular proliferation was assessed by MTT assay. The pro­autophagic properties of RCE­4 were subsequently confirmed using monomeric red fluorescent protein­green fluorescent protein­microtubule­associated proteins 1A/1B light chain 3B (LC3) adenoviruses and CYTO­ID autophagy assays, and by assessing the accumulation of lipid­modified LC3 (LC3II). The mechanisms of RCE­4­induced autophagy were investigated by western blot analysis. The results demonstrated that inhibiting autophagy significantly promoted RCE­4­induced cell death, indicating that autophagy served a protective role following RCE­4 treatment. In addition, RCE­4­induced autophagy was reflected by increased expression levels of the serine/threonine­protein kinase ULK1, phosphorylated (p)­ULK1, p­Beclin­1 and LC3II, the formation of autophagosomes and autolysosomes, and sequestosome 1 (p62) degradation. Subsequent analysis indicated that RCE­4 activated the AMP­activated protein kinase (AMPK) pathway by upregulating AMPK and p­AMPK, and also inhibited the PI3K and extracellular signal­regulated kinase (ERK) signaling pathways by downregulating p­PI3K, p­Akt, p­mTOR, Ras, c­Raf, p­c­Raf, dual specificity mitogen­activated protein kinase kinase (MEK)1/2, p­MEK1/2 and p­Erk1/2. Additionally, with increased treatment times RCE­4 may impair lysosomal cathepsin activity and inhibit autophagy flux by suppressing the expression of AMPK, p­AMPK, ULK1, p­ULK1 and p­Beclin­1, and upregulating that of p62. These results indicated that the dual RCE­4­induced inhibition of the PI3K and ERK pathways may result in a more significant anti­tumor effect and prevent chemoresistance, compared with the inhibition of either single pathway; furthermore, dual blockade of PI3K and ERK, and the AMPK pathway may be involved in the regulation of autophagy caused by RCE­4. Taken together, RCE­4 induced autophagy to protect cancer cells against apoptosis, but AMPK­mediated autophagy was inhibited in the later stages of RCE­4 treatment. In addition, autophagy inhibition improved the therapeutic effect of RCE­4. These data highlight RCE­4 as a potential candidate for cervical cancer treatment.