PFKFB4 Overexpression Facilitates Proliferation by Promoting the G1/S Transition and Is Associated with a Poor Prognosis in Triple-Negative Breast Cancer

Comparative clinical significance and biological roles of PFKFB family members in oral squamous cell carcinoma

BACKGROUND

Cancer cells promote glycolysis, which supports rapid cell growth and proliferation. Phosphofructokinase-fructose bisphosphatases (PFKFBs), a family of bidirectional glycolytic enzymes, play key roles in the regulation of glycolysis in many types of cancer. However, their roles in oral squamous cell carcinoma (OSCC), the most common type of oral cancer, are still unknown.

METHODS

We compared the gene expression levels of PFKFB family members and analyzed their clinical significance in oral cancer patients, whose clinical data were obtained the Cancer Genome Atlas database. Moreover, real-time quantitative polymerase chain reaction, western blotting, assays for cell viability, cell cycle, cell migration and viability of cell spheroid were performed in scramble and PFKFB-silenced cells.

RESULTS

We discovered that PFKFB3 expression in tumor tissues was slightly higher than that in tumor adjacent normal tissues but that PFKFB4 expression was significantly higher in the tumor tissues of oral cancer patients. High PFKFB3 and PFKFB4 expression had different effects on the prognosis of oral cancer patients with different clinicopathological outcomes. Our data showed that PFKFB3 and PFKFB4 play different roles; PFKFB3 is involved in cell viability, G2/M cell cycle progression, invasion, and migration, whereas PFKFB4 is involved in the drug resistance and cancer stemness of OSCC cells. Furthermore, oral cancer patients with co-expressions of PFKFB3/cell cycle or EMT markers and PFKFB4/stemness markers had poor prognosis.

CONCLUSIONS

PFKFB3 and PFKFB4 play different biological roles in OSCC cells, which implying that they might be potential prognostic biomarkers for OSCC patients with certain clinicopathological outcomes.

VRK3 depletion induces cell cycle arrest and metabolic reprogramming of pontine diffuse midline glioma - H3K27 altered cells

We previously identified VRK3 as a specific vulnerability in DMG-H3K27M cells in a synthetic lethality screen targeting the whole kinome. The aim of the present study was to elucidate the mechanisms by which VRK3 depletion impact DMG-H3K27M cell fitness. Gene expression studies after VRK3 knockdown emphasized the inhibition of genes involved in G1/S transition of the cell cycle resulting in growth arrest in G1. Additionally, a massive modulation of genes involved in chromosome segregation was observed, concomitantly with a reduction in the level of phosphorylation of serine 10 and serine 28 of histone H3 supporting the regulation of chromatin condensation during cell division. This last effect could be partly due to a concomitant decrease of the chromatin kinase VRK1 in DMG following VRK3 knockdown. Furthermore, a metabolic switch specific to VRK3 function was observed towards increased oxidative phosphorylation without change in mitochondria content, that we hypothesized would represent a cell rescue mechanism. This study further explored the vulnerability of DMG-H3K27M cells to VRK3 depletion suggesting potential therapeutic combinations, e.g. with the mitochondrial ClpP protease activator ONC201.

Reprogramming of glucose metabolism via PFKFB4 is critical in FGF16-driven invasion of breast cancer cells

Fibroblast growth factors (FGFs) are expressed in both developing and adult tissues and play important roles in embryogenesis, tissue homeostasis, angiogenesis, and neoplastic transformation. Here, we report the elevated expression of FGF16 in human breast tumor and investigate its potential involvement in breast cancer progression. The onset of epithelial-mesenchymal transition (EMT), a prerequisite for cancer metastasis, was observed in human mammary epithelial cell-line MCF10A by FGF16. Further study unveiled that FGF16 alters mRNA expression of a set of extracellular matrix genes to promote cellular invasion. Cancer cells undergoing EMT often show metabolic alteration to sustain their continuous proliferation and energy-intensive migration. Similarly, FGF16 induced a significant metabolic shift toward aerobic glycolysis. At the molecular level, FGF16 enhanced GLUT3 expression to facilitate glucose transport into cells, which through aerobic glycolysis generates lactate. The bi-functional protein, 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase 4 (PFKFB4) was found to be a mediator in FGF16-driven glycolysis and subsequent invasion. Furthermore, PFKFB4 was found to play a critical role in promoting lactate-induced cell invasion since silencing PFKFB4 decreased lactate level and rendered the cells less invasive. These findings support potential clinical intervention of any of the members of FGF16-GLUT3-PFKFB4 axis to control the invasion of breast cancer cells.

Endorsement of TNBC Biomarkers in Precision Therapy by Nanotechnology

Breast cancer is a heterogeneous disease which accounts globally for approximately 1 million new cases annually, wherein more than 200,000 of these cases turn out to be cases of triple-negative breast cancer (TNBC). TNBC is an aggressive and rare breast cancer subtype that accounts for 10-15% of all breast cancer cases. Chemotherapy remains the only therapy regimen against TNBC. However, the emergence of innate or acquired chemoresistance has hindered the chemotherapy used to treat TNBC. The data obtained from molecular technologies have recognized TNBC with various gene profiling and mutation settings that have helped establish and develop targeted therapies. New therapeutic strategies based on the targeted delivery of therapeutics have relied on the application of biomarkers derived from the molecular profiling of TNBC patients. Several biomarkers have been found that are targets for the precision therapy in TNBC, such as EGFR, VGFR, TP53, interleukins, insulin-like growth factor binding proteins, c-MET, androgen receptor, BRCA1, glucocorticoid, PTEN, ALDH1, etc. This review discusses the various candidate biomarkers identified in the treatment of TNBC along with the evidence supporting their use. It was established that nanoparticles had been considered a multifunctional system for delivering therapeutics to target sites with increased precision. Here, we also discuss the role of biomarkers in nanotechnology translation in TNBC therapy and management.

Hypoxic activation of PFKFB4 in breast tumor microenvironment shapes metabolic and cellular plasticity to accentuate metastatic competence

Cancer cells encounter a hostile tumor microenvironment (TME), and their adaptations to metabolic stresses determine metastatic competence. Here, we show that the metabolic enzyme 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-4 (PFKFB4) is induced in hypoxic tumors acquiring metabolic plasticity and invasive phenotype. In mouse models of breast cancer, genetic ablation of PFKFB4 significantly delays distant organ metastasis, reducing local lymph node invasion by suppressing expression of invasive gene signature including integrin β3. Photoacoustic imaging followed by metabolomics analyses of hypoxic tumors show that PFKFB4 drives metabolic flexibility, enabling rapid detoxification of reactive oxygen species favoring survival under selective pressure. Mechanistically, hypoxic induction triggers nuclear translocation of PFKFB4 accentuating non-canonical transcriptional activation of HIF-1α, and breast cancer patients with increased nuclear PFKFB4 in their tumors are found to be significantly associated with poor prognosis. Our findings imply that PFKFB4 induction is crucial for tumor cell adaptation in the hypoxic TME that determines metastatic competence.

RIPOR2 Expression Decreased by HPV-16 E6 and E7 Oncoproteins: An Opportunity in the Search for Prognostic Biomarkers in Cervical Cancer

High-risk human papillomavirus (HPV) infection is the main risk factor for cervical cancer (CC) development, where the continuous expression of E6 and E7 oncoproteins maintain the malignant phenotype. In Mexico, around 70% of CC cases are diagnosed in advanced stages, impacting the survival of patients. The aim of this work was to identify biomarkers affected by HPV-16 E6 and E7 oncoproteins that impact the prognosis of CC patients. Expression profiles dependent on E6 and E7 oncoproteins, as well as their relationship with biological processes and cellular signaling pathways, were analyzed in CC cells. A comparison among expression profiles of E6- and E7-expressing cells and that from a CC cohort obtained from The Cancer Genome Atlas (TCGA) demonstrated that the expression of 13 genes impacts the overall survival (OS). A multivariate analysis revealed that the downregulated expression of RIPOR2 was strongly associated with a worse OS. RIPOR2, including its transcriptional variants, were overwhelmingly depleted in E6- and E7-expressing cells. Finally, in a Mexican cohort, it was found that in premalignant cervical lesions, RIPOR2 expression decreases as the lesions progress; meanwhile, decreased RIPOR2 expression was also associated with a worse OS in CC patients.

Effect of PFKFB4 on the Prognosis and Immune Regulation of NSCLC and Its Mechanism

Background

NSCLC (non-small cell lung cancer) has become the malignancy with the highest incidence and mortality rate worldwide. Fructose-6-phosphate 2-kinase/fructose-2,6-bisphosphatase 4 (PFKFB4) is a key regulator of glycolysis with both kinase and phosphatase activities. The Warburg effect, or increased glycolysis in tumors, provides the metabolic basis for cancer cell proliferation and metastasis, and the Warburg pathway enzyme PFKFB4 is a newly identified important kinase. This study aimed to elucidate the poor prognostic relevance of PFKFB4 in non-small cell lung cancer tissues and its relationship with immune cell infiltration, immune cell biomarkers, and immune checkpoints.

Methods

In this study, immunohistochemical methods were used to assess PFKFB4 expression levels in 140 surgical specimens from patients with histologically confirmed non-small cell lung cancer and to investigate the relationship between PFKFB4 expression levels and the patients’ clinicopathological characteristics. The impact of PFKFB4 expression on prognosis was evaluated using Kaplan–Meier survival analysis and Cox regression analysis.

Results

When compared to normal paracrine tissues, PFKFB4 expression was enhanced in lung cancer tissues, and Kaplan–Meier survival analysis revealed that patients with high PFKFB4 expression had a worse prognosis. In NSCLC, PFKFB4 was found to be associated with immune cell infiltration and immunological checkpoints.

Conclusion

PFKFB4 expression may be upregulated as a sign of poor prognosis in NSCLC, and PFKFB4 may be implicated not only in the genesis and progression of NSCLC but also in its immunological control.

Long Non-Coding RNA LINC01572 Promotes Hepatocellular Carcinoma Progression via Sponging miR-195-5p to Enhance PFKFB4-Mediated Glycolysis and PI3K/AKT Activation

Background: Accumulating evidence indicates that type 2 diabetes mellitus (T2DM) is a risk factor for hepatocellular carcinoma (HCC), and T2DM-associated HCC represents a common type of HCC cases. We herein identify an lncRNA LINC01572 that was aberrantly upregulated in T2DM-related HCC via high-throughput screening. Based on this, the study was undertaken to identify the functional role and mechanism of LINC01572 in HCC progression.

Methods: RT-qPCR was used to detect the expressions of LINC01572 in HCC tissues and cell lines. Gain- or loss-of-function assays were applied to evaluate the in vitro and in vivo functional significance of LINC01572 in the HCC cell proliferation, migration, and invasion using corresponding experiments. Bioinformatics, RIP, RNA pull-down, and luciferase reporter assays were performed to explore the regulatory relationship of the LINC01572/miR-195-5p/PFKFB4 signaling axis.

Result: In this study, we profiled lncRNAs in HCC tissues and corresponding adjacent tissues from HCC patients with T2DM by RNA sequencing. Our data showed that LINC01572 was aberrantly upregulated in HCC tissues as compared with control, especially in those with concurrent T2DM. The high level of LINC01572 was correlated with advanced tumor stage, increased blood HbA1c level, and shortened survival time. The overexpression of LINC01572 significantly promoted HCC cell proliferation, migration, invasion, and epithelial-to-mesenchymal transition (EMT), while the knockdown of LINC01572 had the opposite effects on HCC cells. A mechanistic study revealed that LINC01572-regulated HCC progression via sponging miR-195-5p to increase the level of PFKFB4 and subsequent enhancement of glycolysis and activation of PI3K-AKT signaling.

Conclusion: LINC01572 acts as ceRNA of miR-195-5p to restrict its inhibition of PFKFB4, thereby enhancing glycolysis and activates PI3K/AKT signaling to trigger HCC malignancy.