The gene encoding rat 3-phosphoglycerate dehydrogenase

3-Phosphoglycerate dehydrogenase: a potential target for cancer treatment

BACKGROUND

Metabolic changes have been recognized as an important hallmark of cancer cells. Cancer cells can promote their own growth and proliferation through metabolic reprogramming. Particularly, serine metabolism has frequently been reported to be dysregulated in tumor cells. 3-Phosphoglycerate dehydrogenase (PHGDH) catalyzes the first step in the serine biosynthesis pathway and acts as a rate-limiting enzyme involved in metabolic reprogramming. PHGDH upregulation has been observed in many tumor types, and inhibition of PHGDH expression has been reported to inhibit the proliferation of PHGDH-overexpressing tumor cells, indicating that it may be utilized as a target for cancer treatment. Recently identified inhibitors targeting PHGDH have already shown effectiveness. A further in-depth analysis and concomitant development of PHGDH inhibitors will be of great value for the treatment of cancer.

CONCLUSIONS

In this review we describe in detail the role of PHGDH in various cancers and inhibitors that have recently been identified to highlight progression in cancer treatment. We also discuss the development of new drugs and treatment modalities based on PHGDH targets. Overexpression of PHGDH has been observed in melanoma, breast cancer, nasopharyngeal carcinoma, parathyroid adenoma, glioma, cervical cancer and others. PHGDH may serve as a molecular biomarker for the diagnosis, prognosis and treatment of these cancers. The design and development of novel PHGDH inhibitors may have broad implications for cancer treatment. Therapeutic strategies of PHGDH inhibitors in combination with traditional chemotherapeutic drugs may provide new perspectives for precision medicine and effective personalized treatment for cancer patients.

The Role of D-3-Phosphoglycerate Dehydrogenase in Cancer

Serine, a non-essential amino acid, can be imported from the extracellular environment by transporters and de novo synthesized from glycolytic 3-phosphoglycerate (3-PG) in the serine biosynthetic pathway (SSP). It has been reported that active serine synthesis might be needed for the synthesis of proteins, lipids, and nucleotides and the balance of folate metabolism and redox homeostasis, which are necessary for cancer cell proliferation. Human D-3-phosphoglycerate dehydrogenase (PHGDH), the first and only rate-limiting enzyme in the de novo serine biosynthetic pathway, catalyzes the oxidation of 3-PG derived from glycolysis to 3-phosphohydroxypyruvate (3-PHP). PHGDH is highly expressed in tumors as a result of amplification, transcription, or its degradation and stability alteration, which dysregulates the serine biosynthesis pathway via metabolic enzyme activity to nourish tumors. And some recent researches reported that PHGDH promoted some tumors growth via non-metabolic way by upregulating target cancer-promoting genes. In this article, we reviewed the type, structure, expression and inhibitors of PHGDH, as well as the role it plays in cancer and tumor resistance to chemotherapy.

Positive regulation of promoter activity of human 3-phosphoglycerate dehydrogenase (PHGDH) gene is mediated by transcription factors Sp1 and NF-Y

The PHGDH gene encodes the 3-phosphoglycerate dehydrogenase that catalyzes the transition of 3-phosphoglycerate into 3-phosphohydroxy pyruvate for the phosphorylated pathway of serine biosynthesis. To understand transcriptional regulation of the human PHGDH promoter, a genomic clone containing the 5'-flanking region of the PHGDH gene was isolated from a human genomic library. The 1192-bp PHGDH promoter region was cloned by PCR using the genomic DNA isolated from the PHGDH genomic clone. Sequence analysis of the promoter region exhibited several putative transcription factor binding sites for NF-Y, Sp1, GATA-1, p53, AP2, and AP1, with no TATA-box motif at an appropriate position. Transfection of a series of deletion constructs of the promoter region into HeLa cells revealed that the core positive promoter activity resided in the -276 to +1, which contains two GC-motifs for binding Sp1 and one CCAAT-motif for NF-Y. Mutational analysis and electrophoretic mobility shift assay indicated that both the proximal GC-motif and CCAAT-motif were crucial for full induction of the promoter activity. Chromatin immunoprecipitation analysis confirmed the recruitment of Sp1 and NF-Y to the promoter region in vivo. These results demonstrated that the promoter activity of the human PHGDH gene was positively regulated by the action of transcription factors Sp1 and NF-Y.

Mouse 3-phosphoglycerate dehydrogenase gene: genomic organization, chromosomal localization, and promoter analysis

d-3-Phosphoglycerate dehydrogenase (Phgdh; EC 1.1.1.95) is the first committed enzyme of l-serine biosynthesis in the phosphorylated pathway. We have recently demonstrated that, in developing and mature brain, expression of Phgdh is highly regulated in a cell lineage-specific manner, mainly in neuroepithelial stem cells, radial glia, and astrocytes (J. Neurosci. 21 (2001) 7691; Arch. Histol. Cytol. 66 (2003) 109). To gain insight into the regulatory mechanism of Phgdh expression, we have isolated a mouse genomic clone that contains the entire mouse Phgdh gene. Structural analysis demonstrated that the Phgdh gene spans approximately 27 kilobases (kb) in length and comprises 12 exons with 11 intervening introns. Using fluorescent in situ hybridization (FISH), we mapped the gene to mouse chromosome 3, region F2-F3. Analysis of a 1.8 kb fragment of the 5'-flanking region showed that the classical TATA-box motif near transcription initiation sites was absent. Instead, a GC-rich proximal region containing a potential Sp1 recognition sequence was present; this region is conserved in mouse, rat, and human counterparts. Transient transfection analysis revealed that the cis-acting elements necessary for basal transcription of Phgdh are contained within the -196/+4 proximal sequence of the promoter, in which the conserved Sp1 recognition sites play an important role for basal promoter activity.

Improved radiation hybrid map of rat chromosome 2: colocalization of the genes encoding corticotropin-releasing hormone and IL6-receptor with quantitative trait loci regulating the inflammatory response

We established a radiation hybrid (RH) map of several genes and anonymous markers in the lower half of rat chromosome 2, a chromosome region that contains quantitative trait loci (QTLs) for blood pressure, diabetes and inflammatory response. Two of the newly localized genes (Crh and Il6r) encode proteins involved in the regulation of inflammatory and immune events. Our data show that they reside within regions that were genetically defined as QTLs controlling the inflammatory response. These genes are thus both functional and positional candidates.