AKT2 contributes to increase ovarian cancer cell migration and invasion through the AKT2-PKM2-STAT3/NF-κB axis

Anoikis-related signature predicts prognosis and characterizes immune landscape of ovarian cancer

Ovarian cancer (OV) is the most lethal gynecological malignancy worldwide, with high recurrence rates. Anoikis, a newly-acknowledged form of programmed cell death, plays an essential role in cancer progression, though studies focused on prognostic patterns of anoikis in OV are still lacking. We filtered 32 potential anoikis-related genes (ARGs) among the 6406 differentially expressed genes (DEGs) between the 180 normal controls and 376 TCGA-OV samples. Through the LASSO-Cox analysis, a 2-gene prognostic signature, namely AKT2, and DAPK1, was finally distinguished. We then demonstrated the promising prognostic value of the signature through the K-M survival analysis and time-dependent ROC curves (p-value < 0.05). Moreover, based on the signature and clinical features, we constructed and validated a nomogram model for 1-year, 3-year, and 5-year overall survival, with reliable prognostic values in both TCGA-OV training cohort (p-value < 0.001) and ICGC-OV validation cohort (p-value = 0.030). We evaluated the tumor immune landscape through the CIBERSORT algorithm, which indicated the upregulation of resting Myeloid Dendritic Cells (DCs), memory B cells, and naïve B cells and high expression of key immune checkpoint molecules (CD274 and PDCD1LG2) in the high-risk group. Interestingly, the high-risk group exhibited better sensitivity toward immunotherapy and less sensitivity toward chemotherapies, including Cisplatin and Bleomycin. Especially, based on the IHC of tissue microarrays among 125 OV patients at our institution, we reported that aberrant upregulation of DAPK1 was related to poor prognosis. Conclusively, the anoikis-related signature was a promising tool to evaluate prognosis and predict therapy responses, thus assisting decision-making in the realm of OV precision medicine.

An immune-related exosome signature predicts the prognosis and immunotherapy response in ovarian cancer

BACKGROUND

Cancer-derived exosomes contribute significantly in intracellular communication, particularly during tumorigenesis. Here, we aimed to identify two immune-related ovarian cancer-derived exosomes (IOCEs) subgroups in ovarian cancer (OC) and establish a prognostic model for OC patients based on immune-related IOCEs.

METHODS

The Cancer Genome Atlas (TCGA) database was used to obtain RNA-seq data, as well as clinical and prognostic information. Consensus clustering analysis was performed to identify two IOCEs-associated subgroups. Kaplan-Meier analysis was used to compare the overall survival (OS) between IOCEs-high and IOCEs-low subtype. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted to investigate the mechanisms and biological effects of differentially expressed genes (DEGs) between the two subtypes. Besides, an IOCE-related prognostic model of OC was constructed by Lasso regression analysis, and the signature was validated using GSE140082 as the validation set.

RESULTS

In total, we obtained 21 differentially expressed IOCEs in OC, and identified two IOCE-associated subgroups by consensus clustering. IOCE-low subgroup showed a favorable prognosis while IOCE-high subgroup had a higher level of immune cell infiltration and immune response. GSEA showed that pathways in cancer and immune response were mainly enriched in IOCE-high subgroup. Thus, IOCE-high subgroup may benefit more in immunotherapy treatment. In addition, we constructed a risk model based on nine IOCE-associated genes (CLDN4, AKT2, CSPG5, ALDOC, LTA4H, PSMA2, PSMA5, TCIRG1, ANO6).

CONCLUSION

We developed a novel stratification system for OV based on IOCE signature, which could be used to estimate the prognosis as well as immunotherapy for OC patient.

The potential role of reprogrammed glucose metabolism: an emerging actionable codependent target in thyroid cancer

Although the incidence of thyroid cancer is increasing year by year, most patients, especially those with differentiated thyroid cancer, can usually be cured with surgery, radioactive iodine, and thyroid-stimulating hormone suppression. However, treatment options for patients with poorly differentiated thyroid cancers or radioiodine-refractory thyroid cancer have historically been limited. Altered energy metabolism is one of the hallmarks of cancer and a well-documented feature in thyroid cancer. In a hypoxic environment with extreme nutrient deficiencies resulting from uncontrolled growth, thyroid cancer cells utilize "metabolic reprogramming" to satisfy their energy demand and support malignant behaviors such as metastasis. This review summarizes past and recent advances in our understanding of the reprogramming of glucose metabolism in thyroid cancer cells, which we expect will yield new therapeutic approaches for patients with special pathological types of thyroid cancer by targeting reprogrammed glucose metabolism.

Social, Genetics and Histopathological Factors Related to Titin (TTN) Gene Mutation and Survival in Women with Ovarian Serous Cystadenocarcinoma: Bioinformatics Analysis

Several factors may increase the risk of development of ovarian cancer. In this study, we investigated the relationship between social, genetic, and histopathologic factors in women with ovarian serous cystadenocarcinoma and titin (TTN) mutations, whether the TTN gene mutation may be a predictor, and its impact on mortality and survival in these patients. A total of 585 samples from patients with ovarian serous cystadenocarcinoma were collected from The Cancer Genome Atlas and PanCancer Atlas through the cBioPortal for analysis of social, genetic, and histopathological factors. Logistic regression was used to investigate whether TTN mutation could be a predictor, and the Kaplan-Meier method was applied to analyze survival time. TTN mutation frequency did not differ between age at diagnosis, tumor stage, and race, and was related to increased Buffa hypoxia score (p = 0.004), mutation count (p < 0.0001), Winter hypoxia Score (p = 0.030), nonsynonymous tumor mutation burden (TMB) (p < 0.0001), and reduced microsatellite instability sensor score (p = 0.010). The number of mutations (p < 0.0001) and winter hypoxia score (p = 0.008) were positively associated with TTN mutations, and nonsynonymous TMB (p < 0.0001) proved to be a predictor. Mutated TTN affects the score of genetic variables involved in cancer cell metabolism in ovarian cystadenocarcinoma.

The Role of STATs in Ovarian Cancer: Exploring Their Potential for Therapy

Ovarian cancer (OvCa) is a deadly gynecologic malignancy that presents many clinical challenges due to late-stage diagnoses and the development of acquired resistance to standard-of-care treatment protocols. There is an increasing body of evidence suggesting that STATs may play a critical role in OvCa progression, resistance, and disease recurrence, and thus we sought to compile a comprehensive review to summarize the current state of knowledge on the topic. We have examined peer reviewed literature to delineate the role of STATs in both cancer cells and cells within the tumor microenvironment. In addition to summarizing the current knowledge of STAT biology in OvCa, we have also examined the capacity of small molecule inhibitor development to target specific STATs and progress toward clinical applications. From our research, the best studied and targeted factors are STAT3 and STAT5, which has resulted in the development of several inhibitors that are under current evaluation in clinical trials. There remain gaps in understanding the role of STAT1, STAT2, STAT4, and STAT6, due to limited reports in the current literature; as such, further studies to establish their implications in OvCa are necessitated. Moreover, due to the deficiency in our understanding of these STATs, selective inhibitors also remain elusive, and therefore present opportunities for discovery.

miR-126 regulates the proliferation, migration, invasion, and apoptosis of non-small lung cancer cells via AKT2/HK2 axis

This study tended to clarify the role of miR-126 in non-small cell lung cancer (NSCLC) cell biological behaviors in vitro, containing cell proliferation, migration, invasion, and apoptosis. miRNA expression microarray related to NSCLC was accessed from gene expression omnibus (GEO) database and subjected to differential analysis using the "limma" package. Real-time quantitative PCR was conducted to assess the expression of miR-126 in NSCLC cell lines. wIn vitro experiments including 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), wound healing assay, Transwell, and flow cytometry assay were used for evaluating the effect of miR-126 on cell proliferation, migration, invasion, and apoptosis. Additionally, target mRNA for miR-126 was predicted and further validated by bioinformatics analysis and dual-luciferase reporter assay, respectively. It suggested that miR-126 was significantly down-regulated in NSCLS based on the expression microarray, and similar expression trend was exhibited in cancer cell lines. In the meantime, overexpression of miR-126 was found to result in inhibition of cell proliferation, migration, and invasion while promotion of cell apoptosis, with reductions in protein expression of AKT2 and phosphorylated HK2 (p-HK2) as well. AKT2, identified to be a direct target of miR-126 in NSCLC as judged by dual-luciferase reporter assay. Additionally, overexpression of AKT2 was observed to have the ability of elevating p-HK2 protein expression and reversing the effect of miR-126 on NSCLC cell proliferation, migration, and invasion. Given the above findings, we can see that miR-126 exerts its role in NSCLC cell proliferation, migration, invasion, and apoptosis with the aid of AKT2/HK2 axis.

A diagnostic miRNA panel to detect recurrence of ovarian cancer through artificial intelligence approaches

BACKGROUND

Ovarian Cancer (OC) is the deadliest gynecology malignancy, whose high recurrence rate in OC patients is a challenging object. Therefore, having deep insights into the genetic and molecular mechanisms of OC recurrence can improve the target therapeutic procedures. This study aimed to discover crucial miRNAs for the detection of tumor recurrence in OC by artificial intelligence approaches.

METHOD

Through the ANOVA feature selection method, we selected 100 candidate miRNAs among 588 miRNAs. For their classification, a deep-learning model was employed to validate the significance of the candidate miRNAs. The accuracy, F1-score (high-risk), and AUC-ROC of classification test data based on the 100 miRNAs were 73%, 0.81, and 0.65, respectively. Association rule mining was used to discover hidden relations among the selected miRNAs.

RESULT

Five miRNAs, including miR-1914, miR-203, miR-135a-2, miR-149, and miR-9-1, were identified as the most frequent items among high-risk association rules. The identified miRNAs may target genes/proteins involved in epithelial-mesenchymal transition (EMT), resistance to therapy, and cancer stem cells; being responsible for the heterogeneity and plasticity of the tumor. Our conclusion presents mir-1914 as the significant candidate miRNA and the most frequent item. Current knowledge indicates that the dysregulated miR-1914 may function as a tumor suppressor or oncogene in the development of cancer.

CONCLUSION

These candidate miRNAs can be considered a powerful tool in the diagnosis of OC recurrence. We hypothesize that mir-1914 might open a new line of research in the realm of managing the recurrence of OC and could be a significant factor in triggering OC recurrence.

La protein regulates protein expression by binding with the mRNAs of target genes and participates the pathological process of ovarian cancer

Research on the mechanism and new targets of ovarian cancer is of great significance to reduce the high mortality and drug resistance of ovarian cancer. Human La protein has been found to be highly expressed in a variety of malignant tumors and plays a role in tumorigenesis and development through its RNA-binding function. However, its role and mechanism in ovarian cancer are not completely clear. The present study showed that La protein was highly expressed in serum and tissues of patients with ovarian cancer by ELISA and immunohistochemistry, and the high expression of La protein was associated with the increased degree of malignancy and poor prognosis by searching the KM plotter database. Interference of the La gene resulted in a significant decrease in the proliferation, migration, and invasion of ovarian cancer cells with growth block in the G1 phase and increasing apoptosis. By RNA binding protein immunoprecipitation, transcriptome sequencing, and proteomics, 14 downstream target genes were screened. The La protein might affect the protein expression of these 14 genes by binding with the mRNAs. Therefore, it played a role in the pathological process of ovarian cancer.

Human papillomavirus16 E6 but not E7 upregulates GLUT1 expression in lung cancer cells by upregulating thioredoxin expression

Background and objective: E6 and E7 proteins in human papillomavirus (HPV) 16 are major oncogenes in several types of tumors, including lung cancer. Previous studies have demonstrated that both E6 and E7 oncoproteins can upregulate GLUT1 protein and mRNA expression levels in lung cancer cells. Thus, the present study aimed to investigate the main differences in the molecular mechanisms of GLUT1 expression regulated by E6 and E7. Methods: The double directional genetic manipulation and immunofluorescence were performed to explore the molecular mechanism of E6 or E7 upregulating the expression of GLUT1 in H1299 and A549 cell lines. Results: The overexpression of E6 in well-established lung cancer cell lines upregulated thioredoxin (Trx) protein expression. Notably, plasmid transfection or small interfering RNA transfection with E7 had no regulatory effect on Trx expression. As an important disulfide reductase of the intracellular antioxidant system, Trx plays important role in maintaining oxidative stress balance and protecting cells from oxidative damage. The overexpression of Trx increased the activation of NF-κB by upregulating p65 expression and promoting p65 nuclear translocation, and further upregulated GLUT1 protein and mRNA expression levels. The results of the present study demonstrated that E6, but not E7, upregulated GLUT1 expression in lung cancer cells by activating NF-κB due to the participation of Trx. Conclusion: These results suggest that Trx plays an important role in the pathogenesis of HPV-associated lung cancer, and propose a novel therapeutic target for HPV-associated lung cancer.

Robust estimation and variable selection for the accelerated failure time model

This article concerns robust modeling of the survival time for cancer patients. Accurate prediction of patient survival time is crucial to the development of effective therapeutic strategies. To this goal, we propose a unified Expectation-Maximization approach combined with the L1 -norm penalty to perform variable selection and parameter estimation simultaneously in the accelerated failure time model with right-censored survival data of moderate sizes. Our approach accommodates general loss functions, and reduces to the well-known Buckley-James method when the squared-error loss is used without regularization. To mitigate the effects of outliers and heavy-tailed noise in real applications, we recommend the use of robust loss functions under the general framework. Furthermore, our approach can be extended to incorporate group structure among covariates. We conduct extensive simulation studies to assess the performance of the proposed methods with different loss functions and apply them to an ovarian carcinoma study as an illustration.

Atrazine Promoted Epithelial Ovarian Cancer Cells Proliferation and Metastasis by Inducing Low Dose Reactive Oxygen Species (ROS)

Background:

Atrazine (ATZ) is a triazine herbicide that is widely used in agriculture and has been detected in surface and underground water. Recently, laboratory and epidemiological research have found that the bioaccumulation of ATZ in the environment leads to biotoxicity in the human immune and endocrine systems and results in tumor development.

Objective:

To investigate the effects of ATZ exposure on epithelial ovarian cancer (EOC) cells and elucidate the potential mechanisms governing these effects.

Materials and Methods:

The human EOC cell lines Skov3 and A2780 were used in this study to explore the effects and mechanisms of ATZ exposure on EOC. The mouse embryonic osteoblastic precursor MC3T3-E1 cells served as the control cells to determine the effects of ATZ on cancer cell lines. After exposure to ATZ, the MTT assay, flow cytometry, the colony formation assay, immunohistochemical staining, the cell scratch assay, and the Transwell assay were used to evaluate the proliferative activity, invasion, and migration capabilities of EOC cell lines. Moreover, flow cytometry was also applied to detect the level of reactive oxygen species (ROS) in these two EOC cell lines, as well as the MC3T3-E1 cells. To further illustrate the underlying mechanisms governing the effect of ATZ on EOC, real-time PCR and Western blotting were employed to assess the transcription and the expression level of Stat3 signaling pathway-related genes in Skov3 and MC3T3-E1 cells.

Results:

The results showed that following ATZ treatment, the cell proliferation, migration, and invasion potencies of Skov3 and A2780 cells were increased compared to those of the control group. Meanwhile, the ROS levels of EOC and MC3T3-E1 cells were notably elevated after ATZ treatment. In Skov3 cells, the expression levels of p53 and p21 were downregulated, while those of Cyclin E, vascular endothelial growth factor (VEGF), matrix metallopeptidase 2 (MMP2), MMP9, signal transducers and activators of transcription 3 (Stat3), and p-Stat3 were upregulated by ATZ treatment. In MC3T3-E1 cells, however, ATZ treatment did not affect the level of p53/p21 mRNA compared to the control groups. Moreover, there was no significant change in the expression levels of Stat3 and p-Stat3 in MC3T3-E1 cells exposed to ATZ. This phenomenon was observed while the proliferation rate was enhanced in MC3T3-E1 cells by ATZ.

Conclusions:

The results of this study suggest that ATZ effectively promotes the proliferation and metastasis of EOC cells through the Stat3 signaling pathway by inducing low levels of ROS. Additionally, although ATZ might also induce proliferative potential in normal cells, the mechanisms governing its effects in these cells might be different from those in EOC cells.

Targeting Pyruvate Kinase M2 Phosphorylation Reverses Aggressive Cancer Phenotypes

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype with low survival rate and a lack of biomarkers and targeted treatments. Here, we target pyruvate kinase M2 (PKM2), a key metabolic component of oncogenesis. In patients with TNBC, PKM2pS37 was identified as a prominent phosphoprotein corresponding to the aggressive breast cancer phenotype that showed a characteristic nuclear staining pattern and prognostic value. Phosphorylation of PKM2 at S37 was connected with a cyclin-dependent kinase (CDK) pathway in TNBC cells. In parallel, pyruvate kinase activator TEPP-46 bound PKM2pS37 and reduced its nuclear localization. In a TNBC mouse xenograft model, treatment with either TEPP-46 or the potent CDK inhibitor dinaciclib reduced tumor growth and diminished PKM2pS37. Combinations of dinaciclib with TEPP-46 reduced cell invasion, impaired redox balance, and triggered cancer cell death. Collectively, these data support an approach to identify PKM2pS37-positive TNBC and target the PKM2 regulatory axis as a potential treatment. SIGNIFICANCE: PKM2 phosphorylation marks aggressive breast cancer cell phenotypes and targeting PKM2pS37 could be an effective therapeutic approach for treating triple-negative breast cancer.

Dual Covalent Inhibition of PKM and IMPDH Targets Metabolism in Cutaneous Metastatic Melanoma

Overcoming acquired drug resistance is a primary challenge in cancer treatment. Notably, more than 50% of patients with BRAFV600E cutaneous metastatic melanoma (CMM) eventually develop resistance to BRAF inhibitors. Resistant cells undergo metabolic reprogramming that profoundly influences therapeutic response and promotes tumor progression. Uncovering metabolic vulnerabilities could help suppress CMM tumor growth and overcome drug resistance. Here we identified a drug, HA344, that concomitantly targets two distinct metabolic hubs in cancer cells. HA344 inhibited the final and rate-limiting step of glycolysis through its covalent binding to the pyruvate kinase M2 (PKM2) enzyme, and it concurrently blocked the activity of inosine monophosphate dehydrogenase, the rate-limiting enzyme of de novo guanylate synthesis. As a consequence, HA344 efficiently targeted vemurafenib-sensitive and vemurafenib-resistant CMM cells and impaired CMM xenograft tumor growth in mice. In addition, HA344 acted synergistically with BRAF inhibitors on CMM cell lines in vitro. Thus, the mechanism of action of HA344 provides potential therapeutic avenues for patients with CMM and a broad range of different cancers. SIGNIFICANCE: Glycolytic and purine synthesis pathways are often deregulated in therapy-resistant tumors and can be targeted by the covalent inhibitor described in this study, suggesting its broad application for overcoming resistance in cancer.

Tumor-Derived Extracellular Vesicles Promote Activation of Carcinoma-Associated Fibroblasts and Facilitate Invasion and Metastasis of Ovarian Cancer by Carrying miR-630

Ovarian cancer (OC) is a lethal gynecological malignancy. Extracellular vesicles (EVs) are crucial media in cell-to-cell communication by carrying microRNAs (miRs). The current study aims to investigate the underlying mechanism of miR-630 carried by OC cell-derived EVs in regard to invasion and metastasis of OC cells. miRs related to OC metastasis were searched and screened. The expression patterns of screened miRs in human normal fibroblasts (NFs) and carcinoma-associated fibroblasts (CAFs) were detected using RT-qPCR. miR-630 related to OC metastasis and CAFs activation was analyzed further. The levels of FAP and α-SMA were detected using Western blotting and immunofluorescence. The migration of NFs was measured using Transwell assay. OC cell-derived EVs were isolated and identified. Uptake of EVs by NFs was observed using immunofluorescence staining. The culture supernatant of NFs was collected and used to culture the low metastasis cell line OVCAR8. The migration and invasion of OC cells and epithelial mesenchymal transition (EMT) were measured. Moreover, a xenograft model was established by injecting OVCAR8 cells of different groups into nude mice. Lastly, the effect of EV-pretreated NFs on invasion and metastasis of OC cells was observed in vivo. miR-630 was upregulated in OC cells and CAFs, and further associated with CAF activation and OC metastasis. miR-630 overexpression increased the levels of FAP and α-SMA in NFs, resulting in the transformation of NFs into CAFs. EVs carried miR-630 into NFs and EVs promoted CAF activation. miR-630 targeted KLF6. miR-630 inhibition or KLF6 overexpression attenuated EVs-induced CAF activation. EVs activated the NF-κB pathway via the miR-630/KLF6 axis. The conditioned medium of NFs pretreated with EVs promoted the invasion and metastasis of OVCAR8 cells, while downregulating miR-630 in EVs partially inhibited the promotive effect of NFs. EV-pretreated NFs promoted invasion and metastasis of OC in vivo. In conclusion, EVs carried miR-630 into NFs, thereby facilitating CAF activation and promoting invasion and metastasis of OC by inhibiting KLF6 and activating the NF-κB pathway. Our findings might offer a novel mechanism of invasion and metastasis of OC from the perspective of tumor microenvironment.

LncRNA HOTTIP inhibits cell pyroptosis by targeting miR-148a-3p/AKT2 axis in ovarian cancer

Long noncoding RNA HOTTIP is a crucial regulator in multiple types of cancer, including ovarian cancer (OC). However, the biological roles and underlying mechanisms of HOTTIP in OC have rarely been studied. Hence, this study aimed to investigate the functional correlation between HOTTIP and pyroptosis in OC progression. The expression of HOTTIP in OC tissues and cell lines was characterized by quantitative real-time PCR. Cell proliferation was evaluated using Cell Counting Kit-8 and clone formation assays. Western blot was performed to quantify protein levels. A dual-luciferase reporter assay was used to analyze the molecular interaction among HOTTIP, miR-148a-3p, and AKT2. The expression of HOTTIP was significantly upregulated in OC tissue samples and cell lines. The silencing of HOTTIP led to the inhibition of cell proliferation and NLRP1 inflammasome-mediated pyroptosis. In addition, HOTTIP increased AKT2 expression by negatively regulating miR-148a-3p and then inhibited ASK1/JNK signaling. Further rescue experiments revealed that downregulation of miR-148a-3p and overexpression of AKT2 obviously diminished the effects of HOTTIP downregulation in OC cells. Thus, our study elucidated a novel pyroptosis-related mechanism by which HOTTIP participated in OC progression, which might provide a theoretical reference for clinical treatment.

The role of PKM2 nuclear translocation in the constant activation of the NF-κB signaling pathway in cancer-associated fibroblasts

Cancer-associated fibroblasts (CAFs) play critical roles in cancer progression by regulating tumor cell proliferation, angiogenesis, and metastasis. Recent studies demonstrated that CAFs induce inhibitory immune cell infiltration and chemotherapy resistance in gastric cancer by activating the NF-κB signaling pathway to secrete IL6, IL8, and other inflammatory factors. Inhibition of the NF-κB signaling pathway in CAFs might be a potential therapeutic strategy in gastric cancer. However, how the NF-κB pathway is activated in CAFs remains unclear. We showed that mesenchymal stem cells (MSCs) differentiated into CAFs, induced by the exosomes derived from gastric cancer cells. During the process of differentiation from MSCs into CAFs, we showed that nuclear PKM2 expression was continuously upregulated and associated with NF-κB P65 acetylation, contributing to P65 nuclear retention in CAFs and constant transcription of IL-6, IL-8, and other inflammatory factors, thus promoting gastric cancer cell proliferation. We showed that NF-κB P65 acetylation was induced by P300. We showed that nuclear PKM2 was derived from exosomes of gastric cancer cell lines and the positive feedback loop induced by PKM2-P65 combination. It is also proved that P300 inhibitors can inhibit tumor proliferation in an AGS subcutaneous xenograft tumor model. Our study showed that gastric cancer cells influence the continuous activation of the NF-κB signaling pathway in CAFs by secreting gastric cancer exosomes containing PKM2, thus inducing abnormal metabolism and inflammation activation. This study provides a new therapeutic target for CAF normalization or deactivation strategies.

SAM68 promotes tumorigenesis in lung adenocarcinoma by regulating metabolic conversion via PKM alternative splicing

Background: A metabolic "switch" from oxidative phosphorylation to glycolysis provides tumor cells with energy and biosynthetic substrates, thereby promoting tumorigenesis and malignant progression. However, the mechanisms controlling this metabolic switch in tumors is not entirely clear. Methods: Clinical specimens were used to determine the effect of SAM68 on lung adenocarcinoma (LUAD) tumorigenesis and metastasis, and mouse models and molecular biology assays were performed to elucidate the function and underlying mechanisms in vitro and in vivo. Results:SAM68 mRNA levels were higher in LUAD tissue than in normal lung tissue, indicating that SAM68 expression is upregulated in LUAD. Patients with LUAD with SAM68high (n = 257) had a higher frequency of tumor recurrence (p = 0.025) and recurrence-free survival (p = 0.013) than did those with SAM68low (n = 257). Patients with SAM68high mRNA levels (n = 257) were at a higher risk for cancer-related death (p = 0.006), and had shorter overall survival (p = 0.044) than did those with SAM68low. SAM68 promotes tumorigenesis and metastasis of LUAD cells in vitro and in vivo by regulating the cancer metabolic switch. SAM68 drives cancer metabolism by mediating alternative splicing of pyruvate kinase (PKM) pre-mRNAs, and promoting the formation of PKM2. Mechanistically, SAM68 increased the binding of the splicing repressor hnRNP A1 to exon 9 of PKM, thereby enhancing PKM2 isoform formation and PKM2-dependent aerobic glycolysis and tumorigenesis. Conclusions: SAM68 promotes LUAD cell tumorigenesis and cancer metabolic programming via binding of the 351-443 aa region of SAM68 to the RGG motif of hnRNP A1, driving hnRNP A1-dependent PKM splicing, contributing to increased oncogene PKM2 isoform formation and inhibition of PKM1 isoform formation. SAM68 is therefore a promising therapeutic target for the treatment of LUAD.

Long Non-Coding RNA AC118344.1 Promotes Gastric Cancer Cell Proliferation, Invasion, and Metastasis via AKT2 and Its Downstream Molecules HK2 and MMP2

Background

Gastric cancer (GC) is a highly occurring cancer with poor prognosis. Reports indicate that long non-coding RNA (LncRNA) potentially regulates tumor progression. Herein, we aim to explore the effect of LncRNA AC118344.1 on the progression of gastric cancer.

Methods

Overexpression and knockout experiments were used to clarify the potential molecular signaling mechanisms induced by AC118344.1. CCK-8, transwell and in vivo metastasis assay were used to detect the function of AC118344.1 in AGS and SGC-7901 cells. Additionally, shRNA silencing techniques, qRT-PCR and Western blot assay were used to explore the relationship between AC118344.1, AKT2, and its downstream molecules.

Results

Upregulating the expression of AC118344.1 induces cell proliferation, invasion in vitro, and lung metastasis in vivo whereas downregulating the expression of AC118344.1 inhibits these effects. Besides, silencing the expression of AC118344.1 downregulated the expression of AKT2 in both the two cells. On the other hand, silencing the expression of AKT2 by shRNA was unable to downregulate the expression of AC118344.1 in both the gastric cancer cells. Also, AC118344.1 regulated AKT2 via its downstream molecules including HK2 and MMP2.

Conclusion

AC118344.1 promotes gastric cancer cell proliferation and invasion and lung metastasis in nude mice by upregulating the expression of AKT2 and its downstream molecules (HK2 and MMP2). Therefore, our findings provide a novel mechanism of the AC118344.1-AKT2-HK2/MMP2 axis in regulating the development of gastric cancer cells.

Protein kinase function of pyruvate kinase M2 and cancer

Pyruvate kinase is a terminal enzyme in the glycolytic pathway, where it catalyzes the conversion of phosphoenolpyruvate to pyruvate and production of ATP via substrate level phosphorylation. PKM2 is one of four isoforms of pyruvate kinase and is widely expressed in many types of tumors and associated with tumorigenesis. In addition to pyruvate kinase activity involving the metabolic pathway, increasing evidence demonstrates that PKM2 exerts a non-metabolic function in cancers. PKM2 has been shown to be translocated into nucleus, where it serves as a protein kinase to phosphorylate various protein targets and contribute to multiple physiopathological processes. We discuss the nuclear localization of PKM2, its protein kinase function and association with cancers, and regulation of PKM2 activity.

The Warburg Effect 97 Years after Its Discovery

The deregulation of the oxidative metabolism in cancer, as shown by the increased aerobic glycolysis and impaired oxidative phosphorylation (Warburg effect), is coordinated by genetic changes leading to the activation of oncogenes and the loss of oncosuppressor genes. The understanding of the metabolic deregulation of cancer cells is necessary to prevent and cure cancer. In this review, we illustrate and comment the principal metabolic and molecular variations of cancer cells, involved in their anomalous behavior, that include modifications of oxidative metabolism, the activation of oncogenes that promote glycolysis and a decrease of oxygen consumption in cancer cells, the genetic susceptibility to cancer, the molecular correlations involved in the metabolic deregulation in cancer, the defective cancer mitochondria, the relationships between the Warburg effect and tumor therapy, and recent studies that reevaluate the Warburg effect. Taken together, these observations indicate that the Warburg effect is an epiphenomenon of the transformation process essential for the development of malignancy.

PKM2-c-Myc-Survivin Cascade Regulates the Cell Proliferation, Migration, and Tamoxifen Resistance in Breast Cancer

The M2 isoform of pyruvate kinase (PKM2), as a key glycolytic enzyme, plays important roles in tumorigenesis and chemotherapeutic drug resistance. However, the intricate mechanism of PKM2 as a protein kinase regulating breast cancer progression and tamoxifen resistance needs to be further clarified. Here, we reported that PKM2 controls the expression of survivin by phosphorylating c-Myc at Ser-62. Functionally, PKM2 knockdown suppressed breast cancer cell proliferation and migration, which could be rescued by overexpression of survivin. Interestingly, we found that the level of PKM2 expression was upregulated in the tamoxifen resistant breast cancer cells MCF-7/TAMR, and knockdown of PKM2 sensitized the cells to 4-hydroxytamoxifen (4OH-T). In addition, the elevated level of PKM2 correlates with poor relapse-free survival in breast cancer patients treated with tamoxifen. Overall, our findings demonstrated that PKM2–c-Myc–survivin cascade regulated the proliferation, migration and tamoxifen resistance of breast cancer cells, suggesting that PKM2 represents a novel prognostic marker and an attractive target for breast cancer therapeutics, and that PKM2 inhibitor combined with tamoxifen may be a promising strategy to reverse tamoxifen resistance in breast cancer patients.

Phosphoribosyl Pyrophosphate Amidotransferase Promotes the Progression of Thyroid Cancer via Regulating Pyruvate Kinase M2

Background

Pyruvate kinase is an enzyme that catalyzes the conversion of phosphoenolpyruvate and ADP to pyruvate and ATP in glycolysis and plays a role in regulating cell metabolism. It is reported that the activity of pyruvate kinase is increased in cancers. Phosphoribosyl amidotransferase (PPAT) is reported to be a crucial regulator for pyruvate kinase activity in lung cancer. However, its role in thyroid cancer remains largely unknown.

Materials and Methods

Immunohistochemical analysis and qRT-PCR were used to detect the expression of PPAT in thyroid cancer samples. Both gain-of-function and loss-of-function models were constructed in thyroid cancer cell lines and the biological functions of PPAT on cellular phenotypes were studied using CCK-8 assay and transwell assay in vitro, respectively. Then, Western blot was used to evaluate the change of PKM2 and downstream signal pathways after PPAT was overexpressed or knocked down.

Results

Immunohistochemical analysis showed increased expression of PPAT in thyroid cancer tissues, and it was associated with unfavorable pathological characteristics. Knockdown and overexpression assays suggested that altering PPAT expression modulated cell proliferation, migration, and invasion. In terms of mechanism, PPAT could positively regulate the expression of PKM2 and activate ERK and STAT3 signaling pathways.

Conclusion

PPAT plays crucial roles in regulating proliferation, migration, and invasion of thyroid cancer cells via activating PKM2, ERK, and STAT3.

Serotonin activates glycolysis and mitochondria biogenesis in human breast cancer cells through activation of the Jak1/STAT3/ERK1/2 and adenylate cyclase/PKA, respectively

BACKGROUND

Although produced by several types of tumours, the role of serotonin on cancer biology is yet to be understood.

METHODS

The effects of serotonin (5-HT) on human breast cancer cells proliferation, signalling pathways and metabolic profile were evaluated by cytometry, western blotting, qPCR, enzymology and confocal microscopy.

RESULTS

Our results revealed that incubation of MCF-7 cells with 10 µM 5-HT increased cell growth rate by 28%, an effect that was prevented by the 5-HTR2A/C antagonist, ketanserin. Conversely, increasing concentrations of 5-HT promoted glucose consumption and lactate production by MCF-7 cells. We also showed that increased glucose metabolism is provoked by the upregulation of pyruvate kinase M2 (PKM2) isoform through 5-HTR2A/C-triggered activation of Jak1/STAT3 and ERK1/2 subcellular pathways. However, we noticed a decrease in the rate of produced lactate per consumed glucose as a function of the hormone concentration, suggesting a disruption of the Warburg effect. The latter effect is due to 5-HTR2A/C-dependent mitochondrial biogenesis and metabolism, which is triggered by adenylyl cyclase/PKA, enhancing the oxidation of lactate within these cells.

CONCLUSIONS

We showed that serotonin, through 5-HTR2A/C, interferes with breast cancer cells proliferation and metabolism by triggering two distinct signalling pathways: Jak1/STAT3 that boosts glycolysis through upregulation of PKM2, and adenylyl cyclase/PKA that enhances mitochondrial biogenesis.

Activation of STAT3 and STAT5 Signaling in Epithelial Ovarian Cancer Progression: Mechanism and Therapeutic Opportunity

Epithelial ovarian cancer (EOC) is the most lethal of all gynecologic malignancies. Despite advances in surgical and chemotherapeutic options, most patients with advanced EOC have a relapse within three years of diagnosis. Unfortunately, recurrent disease is generally not curable. Recent advances in maintenance therapy with anti-angiogenic agents or Poly ADP-ribose polymerase (PARP) inhibitors provided a substantial benefit concerning progression-free survival among certain women with advanced EOC. However, effective treatment options remain limited in most recurrent cases. Therefore, validated novel molecular therapeutic targets remain urgently needed in the management of EOC. Signal transducer and activator of transcription-3 (STAT3) and STAT5 are aberrantly activated through tyrosine phosphorylation in a wide variety of cancer types, including EOC. Extrinsic tumor microenvironmental factors in EOC, such as inflammatory cytokines, growth factors, hormones, and oxidative stress, can activate STAT3 and STAT5 through different mechanisms. Persistently activated STAT3 and, to some extent, STAT5 increase EOC tumor cell proliferation, survival, self-renewal, angiogenesis, metastasis, and chemoresistance while suppressing anti-tumor immunity. By doing so, the STAT3 and STAT5 activation in EOC controls properties of both tumor cells and their microenvironment, driving multiple distinct functions during EOC progression. Clinically, increasing evidence indicates that the activation of the STAT3/STAT5 pathway has significant correlation with reduced survival of recurrent EOC, suggesting the importance of STAT3/STAT5 as potential therapeutic targets for cancer therapy. This review summarizes the distinct role of STAT3 and STAT5 activities in the progression of EOC and discusses the emerging therapies specifically targeting STAT3 and STAT5 signaling in this disease setting.

SREBP-1 inhibitor Betulin enhances the antitumor effect of Sorafenib on hepatocellular carcinoma via restricting cellular glycolytic activity

Lipid metabolism that correlates tightly to the glucose metabolic regulation in malignant cells includes hepatocellular carcinoma (HCC) cells. The transcription factor Sterol Regulatory Element Binding Protein 1 (SREBP-1), a regulator of fatty acid synthesis, has been shown to pivotally regulate the proliferation and metastasis of HCC cells. However, the intrinsic mechanism by which SREBP-1 regulates the survival of HCC cells remains unclear. In this study, among HCC patients who had dismal responses to Sorafenib, a high SREBP-1 level was found in the tumors and correlated to poor survival. This observation suggested the negative role of SREBP-1 in clinical HCC prognosis. Our mechanistical studies reveal that the inhibition of SREBP-1 via its inhibitor Betulin suppresses cellular glucose metabolism. In addition to the reduced glycolytic activity, a thwarted metastatic potential was observed in HCC cells upon Betulin administration. Moreover, our data show that SREBP-1 inhibition facilitated the antitumor effects of Sorafenib on HCC cells and xenograft tumors.

Myotubularin related protein 7 is essential for the spermatogonial stem cell homeostasis via PI3K/AKT signaling

Myotubularin related protein 7 (MTMR7), a key member of the MTMR family, depicts phosphatase activity and is involved in myogenesis and tumor growth. We have previously identified MTMR7 in the proteomic profile of mouse spermatogonial stem cell (SSC) maturation and differentiation, implying that MTMR7 is associated with neonatal testicular development. In this study, to further explore the distribution and function of MTMR7 in mouse testis, we studied the effect of Mtmr7 knockdown on neonatal testicular development by testicular and SSC culture methods. Our results revealed that MTMR7 is exclusively located in early germ cells. Deficiency of MTMR7 by morpholino in neonatal testis caused excessive SSC proliferation, which was attributable to the aberrant PI3K/AKT signaling activation. Altogether, our study demonstrates that MTMR7 maintains SSC homeostasis by inhibiting PI3K/AKT signaling activation.

Pyruvate kinase M2: A multifarious enzyme in non-canonical localization to promote cancer progression

Rewiring glucose metabolism, termed as Warburg effect or aerobic glycolysis, is a common signature of cancer cells to meet their high energetic and biosynthetic demands of rapid growth and proliferation. Pyruvate kinase M2 isoform (PKM2) is a key player in such metabolic reshuffle, which functions as a rate-limiting glycolytic enzyme in the cytosol of highly-proliferative cancer cells. During the recent decades, PKM2 has been extensively studied in non-canonical localizations such as nucleus, mitochondria, and extracellular secretion, and pertained to novel biological functions in tumor progression. Such functions of PKM2 open a new avenue for cancer researchers. This review summarizes up-to-date functions of PKM2 at various subcellular localizations of cancer cells and draws attention to the translocation of PKM2 from cytosol into the nucleus induced by posttranslational modifications. Moreover, PKM2 in tumor cells could have an important role in resistance acquisition processes against various chemotherapeutic drugs, which have raised a concern on PKM2 as a potential therapeutic target. Finally, we summarize the current status and future perspectives to improve the potential of PKM2 as a therapeutic target for the development of anticancer therapeutic strategies.

CEMIP promotes ovarian cancer development and progression via the PI3K/AKT signaling pathway

CEMIP is a cell migration-inducing protein that is closely associated with carcinogenesis. However, the function of CEMIP has not been reported in ovarian cancer. Here we show that CEMIP expression level in ovarian cancer tissues was higher than that in normal ovaries. Silencing of CEMIP in ovarian cancer cell lines A2780 and OVCAR3 significantly decreased cell proliferation, cell migration and invasion capacity, while the proportion of apoptotic cells was increased. In addition, Western blotting demonstrated that knockdown of CEMIP inhibited activation of the PI3K/AKT signaling pathway. Altogether, these data suggest that CEMIP may promote the development of ovarian cancer by regulating PI3K/AKT signaling.

AKT2 phosphorylation of hexokinase 2 at T473 promotes tumorigenesis and metastasis in colon cancer cells via NF-κB, HIF1α, MMP2, and MMP9 upregulation

It has been well-established that AKT2 plays an important role in the development and progression of colon cancer; however, its precise function remains unclear. In the present study, we found that AKT2 can interact with and phosphorylate hexokinase 2 (HK2), the rate-limiting enzyme in glycolysis. Moreover, threonine phosphorylation dramatically increases its catalytic activity and enhances glycolysis. Mechanistically, AKT2 phosphorylation of HK2 at T473 was found to increase hexokinase activity and lactic acid production. A mutation in the AKT2 phosphorylation site of HK2 substantially reduced the stimulating effects of AKT2 on glycolysis, cellular apoptosis, invasion, tumorigenesis, and metastasis. In addition, AKT2 regulated NF-κB, HIF1Α, MMP2, and MMP9 via the phosphorylation of HK2 at the T473 site. Taken together, AKT2 increases the invasion, tumorigenesis, and metastasis of colon cancer cells in vitro and promotes lung metastasis in nude mice in vivo through the phosphorylation of the T473 site of HK2 by upregulating NF-κB, HIF1α, MMP2, and MMP9. In conclusion, our findings highlight a novel mechanism for the AKT2-HK2-NF-κB/HIF1α/MMP2/MMP9 axis in the regulation of colon cancer progression. Moreover, our results suggest that both AKT2 and HK2 may be potential targets for the treatment of colon cancer.

LINE-1 ORF-1p enhances the transcription factor activity of pregnenolone X receptor and promotes sorafenib resistance in hepatocellular carcinoma cells

Background

LINE-1 ORF-1p is encoded by the human pro-oncogene LINE-1. Our previous work showed that LINE-1 ORF-1p could enhance the resistance of hepatocellular carcinoma (HCC) cells to antitumor agents. However, the mechanisms involved in LINE-1 ORF-1p-mediated drug resistance remain largely unknown.

Materials and methods

The endogenous mRNA level of LINE-1 ORF-1p in clinical HCC specimens was examined using quantitative PCR (qPCR). The prognosis of HCC patients was assessed using time to progression and overall survival. The transcription factor activity of pregnenolone X receptor (PXR) was examined using luciferase gene reporter assays, qPCR, chromatin immunoprecipitation assays and cellular subfraction assays. Protein interaction between LINE-1 ORF-1p and PXR was detected by co-immunoprecipitation. The effect of LINE-1 ORF-1p on sorafenib resistance in HCC cells was studied using in vitro and in vivo models.

Results

A high level of LINE-1 ORF-1p in clinical specimens was related to poor prognosis in patients who received sorafenib treatment. LINE-1 ORF-1p increased the transcription factor activity of PXR by interacting with PXR and enhancing its cytoplasmic/nuclear translocation, and recruiting PXR to its downstream gene promoter, in turn enhancing the expression of the sorafenib resistance-related genes, CYP3A4 and mdr-1. LINE-1 ORF-1p enhanced the resistance to and clearance of sorafenib in HCC cells.

Conclusion

LINE-1 ORF-1p enhances the transcription factor activation of PXR and promotes the clearance of and resistance to sorafenib in HCC cells.

AEBP1 promotes epithelial-mesenchymal transition of gastric cancer cells by activating the NF-κB pathway and predicts poor outcome of the patients

Adipocyte enhancer binding protein 1 (AEBP1) is a transcriptional repressor that plays a critical role in regulating adipogenesis. Recent studies have indicated that AEBP1 might function as a candidate oncogene and is overexpressed in several human malignancies. However, the role of AEBP1 in gastric cancer (GC) remains largely unknown. This study aimed to investigate the expression pattern, prognostic significance and biological function of AEBP1 in human gastric cancer and to explore the underlying mechanism. We found that both the mRNA and protein levels of AEBP1 were significantly increased in human GC tissues. Elevated AEBP1 expression was significantly correlated with poor overall survival in patients with both early-stage (Tumor, Node, Metastases (TNM) TNM I and II) and late-stage (TNM III and IV) GC. Silencing AEBP1 markedly suppressed the proliferation, migration, invasion, metastasis and epithelial-mesenchymal transition of GC cells. Moreover, we demonstrated that knockdown of AEBP1 in GC cells led to inhibition of the NF-κB pathway by hampering the degradation of IκBα. Thus, AEBP1 might be served as a promising prognostic indicator and a potential therapeutic target in human GC.