Cognitive Functions: Human vs. Animal - 4:1 Advantage |-FAM72-SRGAP2-|

Deciphering the molecular landscape of the FAM72 gene family: Implications for stem cell biology and cancer

Family with sequence similarity 72 (FAM72) is a protein-coding gene family located on chromosome 1 in humans, uniquely featuring four paralogs: FAM72A, FAM72B, FAM72C, and FAM72D. While FAM72's presence as a gene pair with the SLIT-ROBO Rho GTPase-activating protein 2 (SRGAP2) is intriguing, its functional roles, particularly in neural stem cells, remain incompletely understood. This review explores the distinct characteristics of FAM72, shedding light on its expression patterns, potential roles in cell cycle regulation, stem cell renewal and implications in neurogenesis and tumorigenesis.

Family with Sequence Similarity 72 (FAM72) - A prospective biomarker for poor prognosis in patients with oral squamous cell carcinoma

OBJECTIVE

To study the effect of FAM72 on the prognosis of patients with oral squamous cell carcinoma (OSCC) and to explore the relationship between FAM72 and OSCC.

DESIGN

We used a vast array of databases and analytical vehicles to assess the relation between FAM72 and OSCC, including The Cancer Genome Atlas (TCGA), Metascape, and MethSurv. We made a preliminary verification of OSCC lines and tissues by real time quantitative polymerase chain reaction (RT-qPCR).

RESULTS

FAM72 was higher in OSCC than in normal tissues. Analysis of univariate COX data indicated that elevated expression of FAM72A, FAM72B, and FAM72C in OSCC was related to poor overall survival. Moreover, FAM72B and FAM72C were independent of overall survival in multiple COX regression. FAM72A-D and its coexpressed genes in Metascape were analyzed by Gene Ontology (GO), they were enriched in cellular cycle, mitotic and DNA metabolism. Gene set enrichment analysis (GSEA) demonstrated an enrichment in pathways related to cell metabolism. Additionally, high FAM72 expression related to a worse prognosis in OSCC patients. FAM72A-D linked to the infiltration of tumor immune cell in OSCC patients. We found that methylation levels are likely linked to prognosis in OSCC patients. We used RT-qPCR to ascertain the differential FAM72B and FAM72C expression levels in cancer and paracancerous tissues of OSCC, human normal oral keratinocytes (HOK), and human tongue squamous cell carcinoma (Cal-33).

CONCLUSION

Our findings indicate that FAM72B and FAM72C are potential molecular markers of poor prognosis in OSCC and may act as novel targets for OSCC treatment strategies.

Identification of a Chemotherapeutic Lead Molecule for the Potential Disruption of the FAM72A-UNG2 Interaction to Interfere with Genome Stability, Centromere Formation, and Genome Editing

Family with sequence similarity 72 A (FAM72A) is a pivotal mitosis-promoting factor that is highly expressed in various types of cancer. FAM72A interacts with the uracil-DNA glycosylase UNG2 to prevent mutagenesis by eliminating uracil from DNA molecules through cleaving the N-glycosylic bond and initiating the base excision repair pathway, thus maintaining genome integrity. In the present study, we determined a specific FAM72A-UNG2 heterodimer protein interaction using molecular docking and dynamics. In addition, through in silico screening, we identified withaferin B as a molecule that can specifically prevent the FAM72A-UNG2 interaction by blocking its cell signaling pathways. Our results provide an excellent basis for possible therapeutic approaches in the clinical treatment of cancer.

FAM72, Glioblastoma Multiforme (GBM) and Beyond

Simple Summary

Glioblastoma multiforme (GBM) is a serious and aggressive cancer disease that has not allowed scientists to rest for decades. In this review, we consider the new gene pair |-SRGAP2–FAM72-| and discuss its role in the cell cycle and the possibility of defining new therapeutic approaches for the treatment of GBM and other cancers via this gene pair |-SRGAP2–FAM72-|.

Abstract

Neural stem cells (NSCs) offer great potential for regenerative medicine due to their excellent ability to differentiate into various specialized cell types of the brain. In the central nervous system (CNS), NSC renewal and differentiation are under strict control by the regulation of the pivotal SLIT-ROBO Rho GTPase activating protein 2 (SRGAP2)—Family with sequence similarity 72 (FAM72) master gene (i.e., |-SRGAP2–FAM72-|) via a divergent gene transcription activation mechanism. If the gene transcription control unit (i.e., the intergenic region of the two sub-gene units, SRGAP2 and FAM72) gets out of control, NSCs may transform into cancer stem cells and generate brain tumor cells responsible for brain cancer such as glioblastoma multiforme (GBM). Here, we discuss the surveillance of this |-SRGAP2–FAM72-| master gene and its role in GBM, and also in light of FAM72 for diagnosing various types of cancers outside of the CNS.

A Novel Divergent Gene Transcription Paradigm-the Decisive, Brain-Specific, Neural |-Srgap2-Fam72a-| Master Gene Paradigm

Brain development and repair largely depend on neural stem cells (NSCs). Here, we suggest that two genes, i.e., Srgap2 (SLIT-ROBO Rho GTPase-activating protein 2) and Fam72a (family with sequence similarity to 72, member A), constitute a single, NSC-specific, |-Srgap2-Fam72a-| master gene pair co-existing in reciprocal functional dependency. This gene pair has a dual, commonly used, intergenic region (IGR) promotor, which is a prerequisite in controlling human brain plasticity. We applied fluorescence cellular microscopy and fluorescence-activated cell sorting (FACS) to assess rat |-Srgap2-Fam72a-| master gene IGR promotor activity upon stimulation with two contrary growth factors: nerve growth factor (Ngf, a differentiation growth factor) and epidermal growth factor (Egf, a mitotic growth factor). We found that Ngf and Egf acted on the same IGR gene promotor element of the |-Srgap2-Fam72a-| master gene to mediate cell differentiation and proliferation, respectively. Ngf mediated Srgap2 expression and neuronal survival and differentiation while Egf activated Fam72a transcription and cell proliferation. Our data provide new insights into the specific regulation of the |-Srgap2-Fam72a-| master gene with its dual IGR promotor that controls two reverse-oriented functional-dependent genes located on opposite DNA strands. This structure represents a novel paradigm for controlling transcription of divergent genes in regulating NSC gene expression. This paradigm may allow for novel therapeutic approaches to restore or improve higher cognitive functions and cure cancers.

A cancer tissue-specific FAM72 expression profile defines a novel glioblastoma multiform (GBM) gene-mutation signature

INTRODUCTION

Glioblastoma multiform (GBM) is a neural stem cell (NSC)-derived malignant brain tumor with complex genetic alterations challenging clinical treatments. FAM72 is a NSC-specific protein comprised of four paralogous genes (FAM72 A-D) in the human genome, but its functional tumorigenic significance is unclear.

METHODS

We conducted an in-depth expression and somatic mutation data analysis of FAM72 (A-D) in GBM using the comprehensive human clinical cancer study database cBioPortal [including The Cancer Genome Atlas (TCGA)].

RESULTS

We established a FAM72 transcription profile across TCGA correlated with the expression of the proliferative marker MKI67 and a tissue-specific gene-mutation signature represented by pivotal genes involved in driving the cell cycle. FAM72 paralogs are overexpressed in cancer cells, specifically correlating with the mitotic cell cycle genes ASPM, KIF14, KIF23, CENPE, CENPE, CEP55, SGO1, and BUB1, thereby contributing to centrosome and mitotic spindle formation. FAM72 expression correlation identifies a novel GBM-specific gene set (SCN9A, MXRA5, ADAM29, KDR, LRP1B, and PIK3C2G) in the de novo pathway of primary GBM predestined as viable targets for therapeutics.

CONCLUSION

Our newly identified primary GBM-specific gene-mutation signature, along with FAM72, could thus provide a new basis for prognostic biomarkers for diagnostics of GBM and could serve as potential therapeutic targets.

Brain plasticity, cognitive functions and neural stem cells: a pivotal role for the brain-specific neural master gene |-SRGAP2-FAM72-|

Due to an aging society with an increased dementia-induced threat to higher cognitive functions, it has become imperative to understand the molecular and cellular events controlling the memory and learning processes in the brain. Here, we suggest that the novel master gene pair |-SRGAP2-FAM72-| (SLIT-ROBO Rho GTPase activating the protein 2, family with sequence similarity to 72) reveals a new dogma for the regulation of neural stem cell (NSC) gene expression and is a distinctive player in the control of human brain plasticity. Insight into the specific regulation of the brain-specific neural master gene |-SRGAP2-FAM72-| may essentially contribute to novel therapeutic approaches to restore or improve higher cognitive functions.

Mind the (sr)GAP - roles of Slit-Robo GAPs in neurons, brains and beyond

The Slit-Robo GTPase-activating proteins (srGAPs) were first identified as potential Slit-Robo effectors that influence growth cone guidance. Given their N-terminal F-BAR, central GAP and C-terminal SH3 domains, srGAPs have the potential to affect membrane dynamics, Rho family GTPase activity and other binding partners. Recent research has clarified how srGAP family members act in distinct ways at the cell membrane, and has expanded our understanding of the roles of srGAPs in neuronal and non-neuronal cells. Gene duplication of the human-specific paralog of srGAP2 has resulted in srGAP2 family proteins that may have increased the density of dendritic spines and promoted neoteny of the human brain during crucial periods of human evolution, underscoring the importance of srGAPs in the unique sculpting of the human brain. Importantly, srGAPs also play roles outside of the nervous system, including during contact inhibition of cell movement and in establishing and maintaining cell adhesions in epithelia. Changes in srGAP expression may contribute to neurodevelopmental disorders, cancer metastasis and inflammation. As discussed in this Review, much remains to be discovered about how this interesting family of proteins functions in a diverse set of processes in metazoans and the functional roles srGAPs play in human disease.