E2F2 enhances the chemoresistance of pancreatic cancer to gemcitabine by regulating the cell cycle and upregulating the expression of RRM2

RRM2 Is a Putative Biomarker and Promotes Bladder Cancer Progression via PI3K/AKT/mTOR Pathway

Bladder cancer (BLCA) is the tenth most common cancer worldwide, characterized by its high recurrence and progression rates. Thus, identifying prognostic biomarkers and understanding its underlying mechanisms are imperative to enhance patient outcomes. In this study, we aimed to investigate the prognostic significance, expression, functional activity, and underlying mechanisms of RRM2 in BLCA. RRM2 expression and its association with pathological grading and survival were investigated in samples from TCGA dataset and BLCA tissue microarray. CCK8 assays, colony formation assays, wound healing, and transwell assays were performed to assess the role of RRM2 in BLCA cell proliferation and migration. Western blot was employed to investigate alterations in markers associated with epithelial-to-mesenchymal transition (EMT), apoptosis, and cell cycle regulation. Gene set enrichment analysis was performed to investigate the biological processes associated with RRM2, which were subsequently validated. The expression of RRM2 was significantly elevated in both BLCA tissues and cells. Our results also indicated a positive correlation between RRM2 expression and high tumor stage, high tumor grade, and poor survival. Knockdown of RRM2 inhibited cell proliferation and migration of BLCA. RRM2 knockdown significantly induced apoptosis and arrested the cell cycle at the G0/G1 phase. Opposite results were observed in the RRM2 overexpression cells. Additionally, our study demonstrates that RRM2 promotes BLCA progression by activating the PI3K/AKT/mTOR pathway. RRM2 is remarkably correlated with poor prognosis in BLCA and facilitate its progression via PI3K/AKT/mTOR pathway. It is suggested that RRM2 might become an effective prognostic biomarker and potential therapeutic target for BLCA.

RRM2 promotes liver metastasis of pancreatic cancer by stabilizing YBX1 and activating the TGF-beta pathway

Pancreatic cancer is one of the most malignant types of cancer, and despite recent advances in treatment, prognosis remains extremely poor. The most common site of pancreatic cancer metastasis is the liver. Elucidating the molecular mechanisms of pancreatic cancer progression and liver metastasis is essential for improving patients' survival. Ribonucleotide reductase subunit M2 (RRM2) has been linked to many types of cancers and is associated with tumor progression. However, the role of RRM2 in the liver metastasis of pancreatic cancer is still unclear. In this study, RRM2 was found to promote the malignant biological behavior of pancreatic cancer and enhance its liver metastasis. Further studies on the downstream molecular mechanisms of RRM2 revealed that RRM2 stabilizes YBX1, upregulates TGFBR1, and activates the TGF-beta pathway to promote pancreatic cancer progression and liver metastasis. In summary, these results suggest that RRM2 may be an effective therapeutic target for pancreatic cancer liver metastasis.

EZH2 inhibition induces senescence via ERK1/2 signaling pathway in multiple myeloma

Epigenetic modifications play an important role in cellular senescence, and enhancer of zeste homolog 2 (EZH2) is a key methyltransferase involved in epigenetic remodeling in multiple myeloma (MM) cells. We have previously demonstrated that GSK126, a specific EZH2 inhibitor, exhibits anti-MM therapeutic efficacy and safety in vivo and in vitro; however, its specific mechanism remains unclear. This study shows that GSK126 induces cellular senescence in MM, which is characterized by the accumulation of senescence-associated heterochromatin foci (SAHF) and p21, and increased senescence-associated β galactosidase activity. Furthermore, EZH2 is inhibited in ribonucleotide reductase regulatory subunit M2 (RRM2)-overexpressing OCI-MY5 and RPMI-8226 cells. RRM2 overexpression inhibits the methyltransferase function of EZH2 and promotes its degradation through the ubiquitin-proteasome pathway, thereby inducing cellular senescence. In this senescence model, Lamin B1, a key component of the nuclear envelope and a marker of senescence, does not decrease but instead undergoes aberrant accumulation. Meanwhile, phosphorylation of extracellular signal-regulated protein kinase (ERK1/2) is significantly increased. The inhibition of ERK1/2 phosphorylation in turn partially restores Lamin B1 level and alleviates senescence. These findings suggest that EZH2 inhibition increases Lamin B1 level and induces senescence by promoting ERK1/2 phosphorylation. These data indicate that EZH2 plays an important role in MM cellular senescence and provide insights into the relationships among Lamin B1, p-ERK1/2, and cellular senescence.

Circ_0000877 accelerates proliferation and immune escape of non-small cell lung cancer cells by regulating microRNA-637/E2F2 axis

BACKGROUND

Recently, circular RNA (circRNA) has become a vital targeted therapy gene for non-small-cell lung cancer (NSCLC) cells. CircRNA_0000877 (Circ_0000877) has been researched in diffuse large B-cell lymphoma (DLBCL). However, whether circ_0000877 regulated NSCLC cell progression is still poorly investigated. The research attempted to investigate the influence of circ_0000877 in NSCLC.

METHODS

Circ_0000877 levels in NSCLC tissues and cell lines were determined applying RT-qPCR. Cell functions were evaluated by CCK-8, EdU, flow cytometry, ELISA, and western blot. Gene interactions were predicted by Cirular RNA interactome database and Target Scan website and certified by dual-luciferase reporter, RIP, and RNA pull-down assays. Finally, mice experimental model was established to explore the effects of circ_0000877 on tumor growth in vivo.

RESULTS

The elevated trend of circ_0000877 expression was discovered in NSCLC tissues compared to para-carcinoma tissues. The clinicopathological data uncovered that up-regulated circ_0000877 was linked to tumor size, differentiation, and TNM stages of NSCLC patients. Knockdown of circ_0000877 inhibited the proliferation, triggered apoptosis, and prohibited immune escape in NSCLC cells. It was certified that miR-637 was directly interacted with circ_0000877 and targeted by E2F2. Overexpressed E2F2 strongly overturned the functions of circ_0000877 knockdown in NSCLC cells. Mice experimental data demonstrated that circ_0000877 knockdown suppressed tumor growth in vivo.

CONCLUSION

The research demonstrated that circ_0000877 exhibited the promotive effect on NSCLC cells proliferation and immune escape by regulating miR-637/E2F2 axis.

Characterization of a G2M checkpoint-related gene model and subtypes associated with immunotherapy response for clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) presents challenges in early diagnosis and effective treatment. In this study, we aimed to establish a prognostic model based on G2M checkpoint-related genes and identify associated clusters in ccRCC through clinical bioinformatic analysis and experimental validation. Utilizing a single-cell RNA dataset (GSE159115) and bulk-sequencing data from The Cancer Genome Atlas (TCGA) database, we analyzed the G2M checkpoint pathway in ccRCC. Differential expression analysis identified 45 genes associated with the G2M checkpoint, leading to the construction of a predictive model with four key genes (E2F2, GTSE1, RAD54L, and UBE2C). The model demonstrated reliable predictive ability for 1-, 3-, and 5-year overall survival, with AUC values of 0.794, 0.790, and 0.794, respectively. Patients in the high-risk group exhibited a worse prognosis, accompanied by significant differences in immune cell infiltration, immune function, TIDE and IPS scores, and drug sensitivities. Two clusters of ccRCC were identified using the "ConsensusClusterPlus" package, cluster 1 exhibited a worse survival rate and was resistant to chemotherapeutic drugs of Axitinib, Erlotinib, Pazopanib, Sunitinib, and Temsirolimus, but not Sorafenib. Targeted experiments on RAD54L, a gene involved in DNA repair processes, revealed its crucial role in inhibiting proliferation, invasion, and migration in 786-O cells. In conclusion, our study offers valuable insights into the molecular mechanisms underlying ccRCC, identifying potential prognostic genes and molecular subtypes associated with the G2M checkpoint. These findings hold promise for guiding personalized treatment strategies in the management of ccRCC.

Acquired and intrinsic gemcitabine resistance in pancreatic cancer therapy: Environmental factors, molecular profile and drug/nanotherapeutic approaches

A high number of cancer patients around the world rely on gemcitabine (GEM) for chemotherapy. During local metastasis of cancers, surgery is beneficial for therapy, but dissemination in distant organs leads to using chemotherapy alone or in combination with surgery to prevent cancer recurrence. Therapy failure can be observed as a result of GEM resistance, threatening life of pancreatic cancer (PC) patients. The mortality and morbidity of PC in contrast to other tumors are increasing. GEM chemotherapy is widely utilized for PC suppression, but resistance has encountered its therapeutic impacts. The purpose of current review is to bring a broad concept about role of biological mechanisms and pathways in the development of GEM resistance in PC and then, therapeutic strategies based on using drugs or nanostructures for overcoming chemoresistance. Dysregulation of the epigenetic factors especially non-coding RNA transcripts can cause development of GEM resistance in PC and miRNA transfection or using genetic tools such as siRNA for modulating expression level of these factors for changing GEM resistance are suggested. The overexpression of anti-apoptotic proteins and survival genes can contribute to GEM resistance in PC. Moreover, supportive autophagy inhibits apoptosis and stimulates GEM resistance in PC cells. Increase in metabolism, glycolysis induction and epithelial-mesenchymal transition (EMT) stimulation are considered as other factors participating in GEM resistance in PC. Drugs can suppress tumorigenesis in PC and inhibit survival factors and pathways in increasing GEM sensitivity in PC. More importantly, nanoparticles can increase pharmacokinetic profile of GEM and promote its blood circulation and accumulation in cancer site. Nanoparticles mediate delivery of GEM with genes and drugs to suppress tumorigenesis in PC and increase drug sensitivity. The basic research displays significant connection among dysregulated pathways and GEM resistance, but the lack of clinical application is a drawback that can be responded in future.

Knockdown of TACC3 inhibits tumor cell proliferation and increases chemosensitivity in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant digestive tract tumor with limited clinical treatments. Transforming acidic coiled-coil-containing protein 3 (TACC3) is a component of the centrosome axis and a member of the TACC family, which affect mitosis and regulate chromosome stability and are involved in tumor development and progression. However, the role of TACC3 in PDAC remains elusive. In this study, by exploiting the TCGA database, we found that high TACC3 expression in PDAC is associated with poor prognosis. shRNA-mediated TACC3 knockdown caused S phase arrest of the cell cycle and inhibited proliferation in PDAC cell lines. Through RNA sequencing and protein co-immunoprecipitation combined with mass spectrometry, KIF11 was identified as a protein that interacts with TACC3. TACC3 stabilizes and regulates KIF11 protein expression levels in PDAC cells through physical interaction. Knockdown of TACC3 or KIF11 resulted in abnormal spindle formation during cell division both in vitro and in vivo. Pharmacological inhibition of TACC3 or KIF11 can suppress tumor cell proliferation and promote apoptosis. Our studies further demonstrated that high expression of TACC3 and KIF11 mediated the resistance of PDAC to gemcitabine, and deficiency of TACC3 or KIF11 increased the sensitivity of PDAC cells to chemotherapy. In conclusion, our study reveals the fundamental role of TACC3 expression in PDAC cell proliferation and chemoresistance, suggesting that TACC3 can be used as a molecular marker to evaluate the prognosis of PDAC.

RRM2‑mediated Wnt/β‑catenin signaling pathway activation in lung adenocarcinoma: A potential prognostic biomarker

The present study aimed to investigate the role and mechanism of action of ribonucleotide reductase M2 (RRM2) in lung adenocarcinoma and its potential as a therapeutic target. Data of patients with lung adenocarcinoma from The Cancer Genome Atlas database were collected and analyzed to evaluate the potential of RRM2 as a biomarker. The expression of RRM2 was evaluated in the A549 cell line and its cisplatin-resistant A549/DDP cell line derivative by western blot and reverse transcription-quantitative PCR. The study also investigated cell proliferation and the mechanism by which RRM2 controls cellular cisplatin resistance using CCK-8 and colony-formation assays. In addition, cell migration was assessed using Transwell assays, and the cell cycle and apoptosis were examined using flow cytometry. RRM2 was highly expressed in lung adenocarcinoma and was associated with the clinical TMN stage. Functional enrichment analysis showed that RRM2 was enriched in the cell cycle. Immune cell infiltration analysis identified 12 types of immune cell that exhibited differences between patients expressing different levels of RRM2. Cellular assays revealed higher levels of RRM2 expression in A549/DDP cells than A549 cells, and its expression was induced by cisplatin. RRM2 knockdown decreased cell proliferation and migration, accelerated apoptosis and caused cell cycle arrest in the S-phase, increasing the sensitivity of A549 and A549/DDP cells to cisplatin through the Wnt/β-catenin signaling pathway. Overexpression of β-catenin reduced the effects of RRM2 knockdown on A549 cells. Lung adenocarcinoma growth may be influenced by RRM2 through the Wnt/β-catenin signaling pathway, suggesting a potential pathway for cancer progression.

A bioinformatics analysis, pre-clinical and clinical conception of autophagy in pancreatic cancer: Complexity and simplicity in crosstalk

Pancreatic cancer (PC) is a serious gastrointestinal tract disease for which the 5-year survival rate is less than 10%, even in developed countries such as the USA. The genomic profile alterations and dysregulated biological mechanisms commonly occur in PC. Macroautophagy/autophagy is a cell death process that is maintained at a basal level in physiological conditions, whereas its level often changes during tumorigenesis. The function of autophagy in human cancers is dual and can be oncogenic and onco-suppressor. Autophagy is a potent controller of tumorigenesis in PC. The supportive autophagy in PC escalates the growth rate of PC cells and its suppression can mediate cell death. Autophagy also determines the metastasis of PC cells, and it can control the EMT in affecting migration. Moreover, starvation and hypoxia can stimulate glycolysis, and glycolysis induction can be mediated by autophagy in enhancing tumorigenesis in PC. Furthermore, protective autophagy stimulates drug resistance and gemcitabine resistance in PC cells, and its inhibition can enhance radiosensitivity. Autophagy can degrade MHC-I to mediate immune evasion and also regulates polarization of macrophages in the tumor microenvironment. Modulation of autophagy activity is provided by silibinin, ursolic acid, chrysin and huaier in the treatment of PC. Non-coding RNAs are also controllers of autophagy in PC and its inhibition can improve therapy response in patients. Moreover, mitophagy shows dysregulation in PC, which can enhance the proliferation of PC cells. Therefore, a bioinformatics analysis demonstrates the dysregulation of autophagy-related proteins and genes in PC as biomarkers.

The Potential Association between E2F2, MDM2 and p16 Protein Concentration and Selected Sociodemographic and Clinicopathological Characteristics of Patients with Oral Squamous Cell Carcinoma

BACKGROUND

E2F transcription factor 2 (E2F2), murine double minute 2 (MDM2) and p16 are some of the key proteins associated with the control of the cell cycle. The aim of this study was to evaluate E2F2, MDM2 and p16 concentrations in the tumour and margin samples of oral squamous cell carcinoma and to assess their association with some selected sociodemographic and clinicopathological characteristics of the patients.

METHODS

The study group consisted of 73 patients. Protein concentrations were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

There were no statistically significant differences in the levels of E2F2, MDM2 or p16 in the tumour samples as compared to the margin specimens. We found that patients with N0 showed significantly lower E2F2 concentrations than patients with N1 in the tumour samples and the median protein concentration of E2F2 was higher in HPV-negative patients in the tumour samples. Moreover, the level of p16 in the margin samples was lower in alcohol drinkers as compared to non-drinkers. Similar observations were found in concurrent drinkers and smokers compared to non-drinkers and non-smokers.

CONCLUSIONS

E2F2 could potentially promote tumour progression and metastasis. Moreover, our results showed a differential level of the analysed proteins in response to alcohol consumption and the HPV status.

E2F2 is upregulated by the ERK pathway and regulates decidualization via MCM4

Cell cycle modulation is an important event during decidualization. E2F2 is a transcription regulator that plays a vital role in cell cycle regulation. However, the biological role of E2F2 in decidualization has not yet been identified. In this study, estrogen (E2) and progestin (P4)-induced in vitro and in vivo decidualization models were applied. Our data showed that the expression levels of E2F2 and its downstream target MCM4 were downregulated in the uterus tissues of E2P4-treated mice compared with control mice. In hESCs, exposure to E2P4 resulted in a significant decrease in E2F2 and MCM4 expression. E2P4 treatment reduced hESC proliferation and ectopic expression of E2F2 or MCM4 elevated the viability of E2P4-treated hESCs. In addition, ectopic expression of E2F2 or MCM4 restored the expression of G1 phase-associated proteins. The ERK pathway was inactivated in E2P4-treated hESCs. Treatment with ERK agonist Ro 67-7476 restored the expression of E2F2, MCM4, and G1 phase-associated proteins that were inhibited by E2P4. Moreover, Ro 67-7476 retracted the levels of IGFBP1 and PRL that were induced by E2P4. Collectively, our results indicate that E2F2 is regulated by ERK signaling and contributes to decidualization via regulation of MCM4. Therefore, E2F2/MCM4 cascade may serve as promising targets for alleviating decidualization dysfunction.