MiR-17-5p-engineered sEVs Encapsulated in GelMA Hydrogel Facilitated Diabetic Wound Healing by Targeting PTEN and p21

Delayed wound healing is a major complication of diabetes, and is associated with impaired cellular functions. Current treatments are unsatisfactory. Based on the previous reports on microRNA expression in small extracellular vesicles (sEVs), miR-17-5p-engineered sEVs (sEVs17-OE) and encapsulated them in gelatin methacryloyl (GelMA) hydrogel for diabetic wounds treatment are fabricated. SEVs17-OE are successfully fabricated with a 16-fold increase in miR-17-5p expression. SEVs17-OE inhibited senescence and promoted the proliferation, migration, and tube formation of high glucose-induced human umbilical vein endothelial cells (HG-HUVECs). Additionally, sEVs17-OE also performs a promotive effect on high glucose-induced human dermal fibroblasts (HG-HDFs). Mechanism analysis showed the expressions of p21 and phosphatase and tensin homolog (PTEN), as the target genes of miR-17-5p, are downregulated significantly by sEVs17-OE. Accordingly, the downstream genes and pathways of p21 and PTEN, are activated. Next, sEVs17-OE are loaded in GelMA hydrogel to fabricate a novel bioactive wound dressing and to evaluate their effects on diabetic wound healing. Gel-sEVs17-OE effectively accelerated wound healing by promoting angiogenesis and collagen deposition. The cellular mechanism may be associated with local cell proliferation. Therefore, a novel bioactive wound dressing by loading sEVs17-OE in GelMA hydrogel, offering an option for chronic wound management is successfully fabricated.

PTEN regulates expression of its pseudogene in glioblastoma cells in DNA methylation-dependent manner

Glioblastoma (GBM) is the most aggressive and frequent type of primary brain cancer in adult patients. One of the key molecular features associated with GBM pathogenesis is the dysfunction of PTEN oncosuppressor. In addition to PTEN gene, humans and several primates possess processed PTEN pseudogene (PTENP1) that gives rise to long non-coding RNA lncPTENP1-S. Regulation and functions of PTEN and PTENP1 are highly interconnected, however, the exact molecular mechanism of how these two genes affect each other remains unclear. Here, we analyzed the methylation level of the CpG islands (CpGIs) in the promoter regions of PTEN and PTENP1 in patient-derived GBM neurospheres. We found that increased PTEN methylation corelates with decreased PTEN mRNA level. Unexpectedly, we showed the opposite trend for PTENP1. Using targeted methylation and demethylation of PTENP1 CpGI, we demonstrated that DNA methylation increases lncPTENP1-S expression in the presence of wild type PTEN protein but decreases lncPTENP1-S expression if PTEN protein is absent. Further experiments revealed that PTEN protein binds to PTENP1 promoter region and inhibits lncPTENP1-S expression if its CpGI is demethylated. Interestingly, we did not detect any effect of lncPTENP1-S on the level of PTEN mRNA, indicating that in GBM cells PTENP1 is a downstream target of PTEN rather than its upstream regulator. Finally, we studied the functions of lncPTENP1-S and demonstrated that it plays a pro-oncogenic role in GBM cells by upregulating the expression of cancer stem cell markers and decreasing cell adhesion.

Extracellular Vesicles Derived from Glioma Stem Cells Affect Glycometabolic Reprogramming of Glioma Cells Through the miR-10b-5p/PTEN/PI3K/Akt Pathway

OBJECTIVE

Glioma is one of the most prevalently diagnosed types of primary malignant brain tumors. Glioma stem cells (GSCs) are crucial in glioma recurrence. This study aims to elucidate the mechanism by which extracellular vehicles (EVs) derived from GSCs modulate glycometabolic reprogramming in glioma.

METHODS

Xenograft mouse models and cell models of glioma were established and treated with GSC-EVs. Additionally, levels and activities of PFK1, LDHA, and FASN were assessed to evaluate the effect of GSC-EVs on glycometabolic reprogramming in glioma. Glioma cell proliferation, invasion, and migration were evaluated using MTT, EdU, Colony formation, and Transwell assays. miR-10b-5p expression was determined, with its target gene PTEN and downstream pathway PI3K/Akt evaluated. The involvement of miR-10b-5p and the PI3K/Akt pathway in the effect of GSC-EVs on glycometabolic reprogramming was tested through joint experiments.

RESULTS

GSC-EVs facilitated glycometabolic reprogramming in glioma mice, along with enhancing glucose uptake, lactate level, and adenosine monophosphate-to-adenosine triphosphate ratio. Moreover, GSC-EV treatment potentiated glioma cell proliferation, invasion, and migration, reinforced cell resistance to temozolomide, and raised levels and activities of PFK1, LDHA, and FASN. miR-10b-5p was highly-expressed in GSC-EV-treated glioma cells while being carried into glioma cells by GSC-EVs. miR-10b-5p targeted PTEN and activated the PI3K/Akt pathway, hence stimulating glycometabolic reprogramming.

CONCLUSION

GSC-EVs target PTEN and activate the PI3K/Akt pathway through carrying miR-10b-5p, subsequently accelerating glycometabolic reprogramming in glioma, which might provide new insights into glioma treatment.

Cerebellar phenotypes in germline PTEN mutation carriers

PTEN hamartoma tumour syndrome (PHTS) comprises different hereditary conditions caused by germline PTEN mutations, predisposing to the development of multiple hamartomas in many body tissues and also increasing the risk of some types of cancer. Cerebellar involvement in PHTS patients has been long known due to the development of a pathognomonic cerebellar hamartoma (known as dysplastic gangliocytoma of the cerebellum or Lhermitte-Duclos disease). Recently, a crucial role of the cerebellum has been highlighted in the pathogenesis of autism spectrum disorders, now recognised as a phenotype expressed in a variable percentage of PHTS children. In addition, rare PTEN variants are indeed identified in medulloblastoma as well, even if they are less frequent than other germline gene mutations. The importance of PTEN and its downstream signalling enzymatic pathways, PI3K/AKT/mTOR, has been studied at different levels in both human clinical settings and animal models, not only leading to a better understanding of the pathogenesis of different disorders but, most importantly, to identify potential targets for specific therapies. In particular, PTEN integrity makes an important contribution to the normal development of tissue architecture in the nervous system, including the cerebellum. Thus, in patients with PTEN germline mutations, the cerebellum is an affected organ that is increasingly recognised in different disorders, whereas, in animal models, cerebellar Pten loss causes a variety of functional and histological alterations. In this review, we summarise the range of cerebellar involvement observed in PHTS and its relationships with germline PTEN mutations, along with the phenotypes expressed by murine models with PTEN deficiency in cerebellar tissue.

NDRG2 acts as a negative regulator of the progression of small-cell lung cancer through the modulation of the PTEN-AKT-mTOR signalling cascade

N-myc downstream-regulated gene 2 (NDRG2) has been recognised as a negative regulator of the progression of numerous tumours, yet its specific role in small-cell lung carcinoma (SCLC) is not fully understood. The purpose of the current study was to investigate the biological role and mechanism of NDRG2 in SCLC. Initial investigation using the Gene Expression Omnibus (GEO) dataset revealed marked downregulation of NDRG2 transcripts in SCLC. The decreased abundance of NDRG2 in SCLC was verified by examining clinical specimens. Increasing NDRG2 expression in SCLC cell lines caused significant changes in cell proliferation, cell cycle progression, colony formation, and chemosensitivity. NDRG2 overexpression decreased the levels of phosphorylated PTEN, AKT and mTOR. In PTEN-depleted SCLC cells, the upregulation of NDRG2 did not result in any noticeable impact on AKT or mTOR activation. Additionally, the reactivation of AKT reversed the antitumour effects of NDRG2 in SCLC cells. Notably, increasing NDRG2 expression retarded the growth of SCLC cell-derived xenografts in vivo. In conclusion, NDRG2 serves as an inhibitor of SCLC, and its cancer-inhibiting effects are achieved through the suppression of AKT/mTOR via the activation of PTEN. This work suggests that NDRG2 is a potential druggable target for SCLC treatment.

Knockdown of miR-24 Suppressed the Tumor Growth of Cervical Carcinoma Through Regulating PTEN/PI3K/AKT Signaling Pathway

Cervical cancer (CC) is the most prevalent malignant tumor in gynecology. Despite routine surgery, advanced CC is hard to remove completely. MicroRNA-24 (miR-24) regulates several types of tumors, but its regulatory function in CC was previously unknown. We established stable knockdown of miR-24 and phosphatase and tensin homolog (PTEN) in CC cells. We measured mRNA and protein expression with RT-PCR and western blotting. We evaluated cell proliferation, invasion, migration, and apoptosis with CCK8, Transwell, wound healing, and flow cytometry, respectively. We also examined the influence of miR-24 and PTEN on tumor growth in a metastatic tumor model in nude mice. The expression of miR-24 was significantly increased in CC tissues and cell lines (C-33A, HeLa S3, SiHa). MiR-24 inhibitor greatly suppressed PTEN/PI3K/AKT, while miR-24 mimic markedly activated this signaling pathway. Knockdown of PTEN significantly reversed the effects of miR-24 inhibitor on cell proliferation, invasion, migration, and apoptosis of CC cells. The significant inhibition effect of tumor growth and ki67 expression caused by miR-24 inhibitor was reversed by si-PTEN. MiR-24 inhibitor significantly suppressed cell proliferation, invasion, migration, epithelial-mesenchymal transition (EMT) process, and tumor growth, while promoting cell apoptosis. However, the influence of miR-24 inhibitor was markedly reversed by si-PTEN. Targeting miR-24 could provide a novel therapeutic strategy for the prevention and treatment of CC.

Immunohistochemical findings and clinicopathological features of breast cancers with pathogenic germline mutations in Non-BRCA genes

Deleterious germline mutations in multiple genes confer an increased breast cancer (BC) risk. Immunohistochemical (IHC) expression of protein products of mutated high-risk genes has not been investigated in BC. We hypothesized that pathogenic mutations may lead to an abnormal IHC expression pattern in the tumor cells. BCs with deleterious germline mutations in CHEK2, ATM, PALB2 & PTEN were identified. Immunohistochemistry was performed using Dako staining platform on formalin fixed paraffin embedded tumor tissue. Primary antibodies for PALB2 (ab202970), ATM [2C1(1A10)}, CHK2 (EPR4325), and PTEN (138G6) proteins were used for BCs with respective deleterious mutations. IHC expression was assessed in tumor and adjacent benign breast tissue. Total 27 BCs with 10 CHEK2, 9 ATM, 6 PALB2 & 2 PTEN deleterious germline mutations were identified. IHC staining was performed on 8 CHEK2, 7 ATM, 6 PALB2 & 2 PTEN cases. Abnormal CHEK2 IHC staining was identified in 7/8(88%) BCs. Three distinct CHK2 IHC patterns were noted: 1) Strong diffuse nuclear positivity (5 BC), 2) Null-pattern (2 BC), & 3) Normal breast-like staining in 1 BC Four of 5 (80%) strong CHK2 staining BC had missense CHEK2 mutations. Null-pattern was present with a missense & a frameshift mutation. Normal breast-like CHEK2 IHC staining pattern was present in 1 BC with CHEK2 frameshift mutation. Loss of nuclear/cytoplasmic PTEN IHC expression was noted in 2 in-situ carcinomas. Abnormal PTEN and CHK2 IHC were present in atypical ductal hyperplasia and flat epithelial atypia. ATM and PALB2 IHC expression patterns were similar in tumor cells and benign breast epithelium: mild to moderate intensity nuclear and cytoplasmic staining. We report abnormal CHEK2 IHC expression in 88% of BCs with pathogenic CHEK2 mutations. With PTEN and CHEK2 pathogenic mutations, abnormal IHC patterns are seen in early atypical proliferative lesions. IHC may be applied to identify CHEK2 & PTEN mutated BCs and precursor lesions.

Overexpression of Transmembrane Phosphatase with Tensin homology (TPTE) in prostate cancer is clinically significant, suggesting its potential as a valuable biomarker

PURPOSE

Cancer testis antigens (CTAs) are a family of proteins typically expressed in male testicles but overexpressed in various cancer cell types. Transmembrane Phosphatase with Tensin homology (TPTE) is expressed only in the testis of healthy individuals and is a member of the family of CTAs. The current study, for the first time, examined the significance of TPTE expression in prostate cancer (PCa) tissues by generating a novel antibody marker targeting TPTE protein.

METHODS

Polyclonal antibodies were prepared for TPTE-p1 and TPTE-p2 peptides, which are derived from the extracellular domains of TPTE. Anti-TPTE-p2 antibody was then used to study the extent and pattern of TPTE expression in 102 PCa and 48 benign prostatic hyperplasia (BPH) tissue samples by immunohistochemistry. The viability of cancer cell lines (PC-3 and MCF-7 cells) was also evaluated in the presence of anti-TPTE-p2 antibody using the MTT test.

RESULTS

The immunohistochemical analysis demonstrated a significant increase in cytoplasmic and membrane TPTE expression in the PCa samples compared to the BPH group (both P < 0.0001). Cytoplasmic TPTE expression was positively correlated with Gleason score and PSA levels (P = 0.03 and P = 0.001, respectively). Significant correlations were identified between the levels of PSA and perineural invasion and the membrane expression (P = 0.01, P = 0.04, respectively). Moreover, anti-TPTE-p2 antibody inhibited PC-3 and MCF-7 cells proliferation compared to the control group for 24 h (P < 0.001 and P = 0.001, respectively) as well as for 48 h (P = 0.001 and P = 0.001, respectively).

CONCLUSION

Our findings indicate that increased TPTE expression is associated with progression of disease. The ability of anti-TPTE-p2 antibody to recognize and target the TPTE protein makes it a potential biomarker to assess and/or target the PCa.

Distinct early role of PTEN regulation during HCMV infection of monocytes

Human cytomegalovirus (HCMV) infection of monocytes is essential for viral dissemination and persistence. We previously identified that HCMV entry/internalization and subsequent productive infection of this clinically relevant cell type is distinct when compared to other infected cells. We showed that internalization and productive infection required activation of epidermal growth factor receptor (EGFR) and integrin/c-Src, via binding of viral glycoprotein B to EGFR, and the pentamer complex to β1/β3 integrins. To understand how virus attachment drives entry, we compared infection of monocytes with viruses containing the pentamer vs. those without the pentamer and then used a phosphoproteomic screen to identify potential phosphorylated proteins that influence HCMV entry and trafficking. The screen revealed that the most prominent pentamer-biased phosphorylated protein was the lipid- and protein-phosphatase phosphatase and tensin homolog (PTEN). PTEN knockdown with siRNA or PTEN inhibition with a PTEN inhibitor decreased pentamer-mediated HCMV entry, without affecting trimer-mediated entry. Inhibition of PTEN activity affected lipid metabolism and interfered with the onset of the endocytic processes required for HCMV entry. PTEN inactivation was sufficient to rescue pentamer-null HCMV from lysosomal degradation. We next examined dephosphorylation of a PTEN substrate Rab7, a regulator of endosomal maturation. Inhibition of PTEN activity prevented dephosphorylation of Rab7. Phosphorylated Rab7, in turn, blocked early endosome to late endosome maturation and promoted nuclear localization of the virus and productive infection.

PTEN decreases NR2F1 expression to inhibit ciliogenesis during EGFRL858R-induced lung cancer progression

Lung cancer is the major cause of death worldwide. Activation of oncogenes or inhibition of tumor suppressors causes cancer formation. Previous studies have indicated that PTEN, as a tumor suppressor, inhibits cancer formation. In this study, we studied the role of PTEN in EGFRL858R-induced lung cancer in vivo. Interestingly, loss of PTEN increased bronchial cell hyperplasia but decreased alveolar cell hyperplasia in EGFRL858R*PTEN-/--induced lung cancer. Systematic analysis of gene expression by RNA-seq showed that several genes related to ciliogenesis were upregulated in EGFRL858R*PTEN-/--induced lung cancer and subsequently showed that bronchial ciliated cells were hyperplastic. Several critical ciliogenesis-related genes, such as Mucin5A, DNAI2, and DNAI3, were found to be regulated by NR2F1. Next, NR2F1 was found to be inhibited by overexpression of PTEN, indicating that PTEN negatively regulates NR2F1, thereby inhibiting the expression of ciliogenesis-related genes and leading to the inhibition of bronchial cell hyperplasia during EGFRL858R-induced lung cancer progression. In addition, we also found that PTEN decreased AKT phosphorylation in A549, KRAS mutant, and H1299 cells but increased AKT phosphorylation in PC9, EGFRL858R, and H1299L858R cells, suggesting that PTEN may function as a tumor suppressor and an oncogene in lung cancers with KRAS mutation and EGFR mutation, respectively. PTEN acts as a double-edged sword that differentially regulates EGFRL858R-induced lung cancer progression in different genomic backgrounds. Understanding the PTEN in lung cancer with different genetic backgrounds will be beneficial for therapy in the future.

Hsa_circ_0004872 alleviates meningioma progression by sponging miR-190a-3p/PTEN signaling

BACKGROUND

Meningioma, the most prevalent intracranial tumor, possesses a significant propensity for malignant transformation. Circular RNAs (circ-RNAs), a class of non-coding RNAs, have emerged as crucial players in tumorigenesis. This study explores the functional relevance of hsa_circ_0004872, a specific circ-RNA, in the context of meningioma.

METHODS

Molecular structure and stability of hsa_circ_0004872 were elucidated through PCR identification. Meningioma cell proliferation and apoptosis were assessed using the CCK-8 assay and flow cytometry, respectively. Gene and protein expression were analyzed via qRT-PCR and western blot. Molecular interactions were confirmed through dual-luciferase reporter gene and RIP assays.

RESULTS

Hsa_circ_0004872, derived from exons 2 to 4 of the host gene MAPK1, demonstrated enhanced stability compared to its host MAPK1. Clinical data described that hsa_circ_0004872 was reduced in meningioma tissues and cell lines, and negatively correlated to poor survival rate of meningioma patients. Overexpression of hsa_circ_0004872 exhibited inhibitory effects on cell proliferation and promotion of apoptosis in vitro. Subsequent investigations unveiled a direct interaction between hsa_circ_0004872 and miR-190a-3p, leading to the activation of the PI3K/AKT signaling pathway through targeting PTEN. Notably, miR-190a-3p silence accelerated the apoptosis and proliferation inhibition of meningioma cells by inactivating PTEN/PI3K/AKT signaling, while miR-190a-3p overexpression showed an opposite effect, which greatly reversed the anti-tumor effects of hsa_circ_0004872 overexpression.

CONCLUSION

In summary, our findings highlighted the intricate role of hsa_circ_0004872 in meningioma, shedding light on the regulatory mechanisms involving circ-RNAs in tumor progression. This positions hsa_circ_0004872 as a potential key regulatory factor in meningioma with implications for future therapeutic interventions.

BET inhibition induces synthetic lethality in PTEN deficient colorectal cancers via dual action on p21CIP1/WAF1

Loss of PTEN tumor suppressor is an important event during colorectal cancer (CRC) development and is a target for therapeutic exploitation. This study reports that bromodomain and extra-terminal motif (BET) is a synthetic lethal partner of PTEN in CRC. BET inhibition (BETi) selectively induced G1 cell cycle arrest and apoptosis in PTEN-/- CRC. Further, BETi selectively and dose-dependently suppressed the growth of PTEN-/- CRC tumor xenografts in mice and patient-derived organoids. Mechanistically, PTEN-deficient CRC cells elevated the level of cytoplasmic p21CIP1/WAF1 that is hyper-phosphorylated at Thr145 by AKT. BETi suppressed AKT activation in PTEN-deficient CRC cells, followed by the reduction in p21 phosphorylation at Thr145, thereby promoting its nuclear translocation. In addition, BETi suppressed MYC level and this in turn increased the total p21 level in the nuclei. Over-expression of a phospho-mimetic p21 mutant (T145D) significantly rescued the BETi effect on PTEN-deficient CRC. These results suggest that BETi has a dual action on p21: elevating the level of p21 by inhibiting MYC and converting the oncogenic (cytoplasmic) p21 into the tumor-suppressive (nuclear) p21 by inhibiting AKT. Taken together, this study identified the synthetic lethal interaction between PTEN and BET, and provides a potential actionable target for CRC with PTEN loss.

Hyperactivity of mTORC1- and mTORC2-dependent signaling mediates epilepsy downstream of somatic PTEN loss

Gene variants that hyperactivate PI3K-mTOR signaling in the brain lead to epilepsy and cortical malformations in humans. Some gene variants associated with these pathologies only hyperactivate mTORC1, but others, such as PTEN, PIK3CA, and AKT, hyperactivate both mTORC1- and mTORC2-dependent signaling. Previous work established a key role for mTORC1 hyperactivity in mTORopathies, however, whether mTORC2 hyperactivity contributes is not clear. To test this, we inactivated mTORC1 and/or mTORC2 downstream of early Pten deletion in a new mouse model of somatic Pten loss-of-function (LOF) in the cortex and hippocampus. Spontaneous seizures and epileptiform activity persisted despite mTORC1 or mTORC2 inactivation alone, but inactivating both mTORC1 and mTORC2 simultaneously normalized brain activity. These results suggest that hyperactivity of both mTORC1 and mTORC2 can cause epilepsy, and that targeted therapies should aim to reduce activity of both complexes.

eEF1A2 promotes PTEN-GSK3β-SCF complex-dependent degradation of Aurora kinase A and is inactivated in breast cancer

The translation elongation factor eEF1A promotes protein synthesis. Its methylation by METTL13 increases its activity, supporting tumor growth. However, in some cancers, a high abundance of eEF1A isoforms is associated with a good prognosis. Here, we found that eEF1A2 exhibited oncogenic or tumor-suppressor functions depending on its interaction with METTL13 or the phosphatase PTEN, respectively. METTL13 and PTEN competed for interaction with eEF1A2 in the same structural domain. PTEN-bound eEF1A2 promoted the ubiquitination and degradation of the mitosis-promoting Aurora kinase A in the S and G2 phases of the cell cycle. eEF1A2 bridged the interactions between the SKP1-CUL1-FBXW7 (SCF) ubiquitin ligase complex, the kinase GSK3β, and Aurora-A, thereby facilitating the phosphorylation of Aurora-A in a degron site that was recognized by FBXW7. Genetic ablation of Eef1a2 or Pten in mice resulted in a greater abundance of Aurora-A and increased cell cycling in mammary tumors, which was corroborated in breast cancer tissues from patients. Reactivating this pathway using fimepinostat, which relieves inhibitory signaling directed at PTEN and increases FBXW7 expression, combined with inhibiting Aurora-A with alisertib, suppressed breast cancer cell proliferation in culture and tumor growth in vivo. The findings demonstrate a therapeutically exploitable, tumor-suppressive role for eEF1A2 in breast cancer.

β-Sitosterol targets ASS1 for Nrf2 ubiquitin-dependent degradation, inducing ROS-mediated apoptosis via the PTEN/PI3K/AKT signaling pathway in ovarian cancer

The exploration of drugs derived from natural sources holds significant promise in addressing current limitations in ovarian cancer (OC) treatments. While previous studies have highlighted the remarkable anti-cancer properties of the natural compound β-sitosterol (SIT) across various tumors, its specific role in OC treatment remains unexplored. This study aims to investigate the anti-tumor activity of SIT in OC using in vitro and in vivo models, delineate potential mechanisms, and establish a preclinical theoretical foundation for future clinical trials, thus fostering further research. Utilizing network pharmacology, we pinpoint SIT as a promising candidate for OC treatment and predict its potential targets and pathways. Through a series of in vitro and in vivo experiments, we unveil a novel mechanism through which SIT mitigates the malignant biological behaviors of OC cells by modulating redox status. Specifically, SIT selectively targets argininosuccinate synthetase 1 (ASS1), a protein markedly overexpressed in OC tissues and cells. Inhibiting ASS1, SIT enhances the interaction between Nrf2 and Keap1, instigating the ubiquitin-dependent degradation of Nrf2, subsequently diminishing the transcriptional activation of downstream antioxidant genes HO-1 and NQO1. The interruption of the antioxidant program by SIT results in the substantial accumulation of reactive oxygen species (ROS) in OC cells. This, in turn, upregulates PTEN, exerting negative regulation on the phosphorylation activation of AKT. The suppression of AKT signaling disrupted downstream pathways associated with cell cycle, cell survival, apoptosis, migration, and invasion, ultimately culminating in the death of OC cells. Our research uncovers new targets and mechanisms of SIT against OC, contributing to the existing knowledge on the anti-tumor effects of natural products in the context of OC. Additionally, this research unveils a novel role of ASS1 in regulating the Nrf2-mediated antioxidant program and governing redox homeostasis in OC, providing a deeper understanding of this complex disease.

Real-World Overall Survival and Treatment Patterns by PTEN Status in Metastatic Castration-Resistant Prostate Cancer

PURPOSE

It is estimated that the PTEN tumor suppressor gene is functionally lost in 40%-50% of patients with metastatic castration-resistant prostate cancer (mCRPC). There is limited information on the prognostic significance of PTEN status identified with genomic testing. This real-world cohort study assessed PTEN as a genetic biomarker using data from US-based oncology practices.

METHODS

This retrospective real-world cohort study used a deidentified US-based metastatic prostate cancer clinicogenomic database linked to longitudinal clinical data derived from electronic health records. Patients were aged 18 years and older and diagnosed with mCRPC between January 1, 2018, and June 30, 2021. Comprehensive genomic profiling (CGP) of tumor specimens was performed using next-generation sequencing. First-line (1L) and second-line (2L) treatment patterns were assessed and stratified by PTEN status. Kaplan-Meier methods and a multivariable Cox model were used to compare the real-world overall survival by PTEN status among patients who received 1L novel hormone therapy or taxanes.

RESULTS

In patients with mCRPC who underwent CGP, PTEN loss of function (LOF) was associated with decreased survival compared with intact PTEN (hazard ratio, 1.61 [95% CI, 1.07 to 2.42]; P = .024). The results were not influenced by 1L treatment type. 1L treatment patterns were similar between intact PTEN and PTEN LOF subgroups, with abiraterone and enzalutamide being the two most common treatments in both groups. Patients with PTEN LOF were less likely to receive 2L treatments than patients with intact PTEN.

CONCLUSION

PTEN LOF, identified with genomic testing, was associated with decreased survival and negative prognoses in patients with mCRPC.

Exosomal miR-93 derived from hepatocellular carcinoma cell promotes the sorafenib resistance of hepatocellular carcinoma through PTEN/PI3K/Akt pathway

Exosomal microRNAs (miRNAs) derived from cancer cell is an important regulatory molecule that mediates the formation of tumor drug resistance, but function and mechanisms of exosomal miRNA in sorafenib resistance of hepatocellular carcinoma (HCC) have not been studied. We detected the level and prognosis of miR-93 in HCC by using TCGA HCC database. For confirming the extracted exosome, transmission electron microscopy was used. Cy3-labeled miR-93 and quantitative reverse transcription-polymerase chain reaction were used to prove that exosomal miR-93 derived from HCC cell can be transferred to sensitive HCC cells. CCK8, EdU, and flow cytometer assay were used to confirm the function of exosomal miR-93 in sorafenib resistance of HCC. Bioinformatics software and luciferase reporter assay was used to confirm the direct targeting relationship between PTEN and miR-93. Western blot was used to validate downstream pathways. We found that miR-93 is overexpressed and a prognostic risk factor for the HCC patients. miR-93 was overexpressed in sorafenib resistant HCC cells compared with sensitive cells, and miR-93 contributed to sorafenib resistance of HCC cells through targeting PTEN. miR-93 was enriched in exosomes that secreted from sorafenib resistant cells, and these exosomal miR-93 promote the spread of sorafenib resistant through targeting PTEN to reactivate PI3K/AKT pathway. Therefore, miR-93 can act as a potential therapeutic target for advanced patients with acquired sorafenib resistance.

Arteriovenous malformations as a presenting sign of PTEN hamartoma tumor syndrome: A case series

High-flow vascular malformations have been associated with multiple syndromes including capillary malformation-arteriovenous malformation (CM-AVM) syndrome, hereditary hemorrhagic telangiectasia syndrome, and less commonly, phosphatase and tensin homolog hamartoma tumor syndrome (PHTS). We present a series of three patients with clinically challenging complex AVMs who were found to have underlying PHTS. In all patients, diagnosis was delayed, and the presence of the AVM prompted sampling and genetic testing for PHTS in the absence of other clinical features of the condition. This series highlights the importance of screening for PHTS in the setting of high-flow vascular malformations.

Spinster homolog 2 reduces malignancies of glioblastoma via PTEN/PI3K/AKT pathway

The molecular mechanisms of glioblastoma (GBM) are unclear, and the prognosis is poor. Spinster homolog 2 (SPNS2) is reportedly involved in pathological processes such as immune response, vascular development, and cancer. However, the biological function and molecular role of SPNS2 in GBM are unclear. SPNS2 is aberrantly low expressed in glioma. Survival curves, risk scores, prognostic nomograms, and univariate and multifactorial Cox regression analyses showed that SPNS2 is an independent prognostic indicator significantly associated with glioma progression and prognosis. Cell function assays and in vivo xenograft transplantation were performed that downregulation of SPNS2 promoted GBM cell growth, migration, invasion, epithelial-mesenchymal transition (EMT), anti-apoptosis, drug resistance, and stemness, while overexpression of SPNS2 had the opposite effect. Meanwhile, the functional enrichment and signaling pathways of SPNS2 in the Cancer Genome Atlas (TCGA), Chinese Glioma Genome Atlas (CGGA), and RNA sequencing were analyzed by Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene set enrichment analysis (GSEA). The above results were related to the inhibition of the PTEN/PI3K/AKT pathway by SPNS2. In addition, we predicted that SPNS2 is closely associated with immune infiltration in the tumor microenvironment by four immune algorithms, ESTIMATE, TIMER, CIBERSORT, and QUANTISEQ. In particular, SPNS2 was negatively correlated with the infiltration of most immune cells, immunomodulators, and chemokines. Finally, single-cell sequencing analysis also revealed that SPNS2 was remarkably correlated with macrophages, and downregulation of SPNS2 promotes the expression of M2-like macrophages. This study provides new evidence that SPNS2 inhibits malignant progression, stemness, and immune infiltration of GBM cells through PTEN/PI3K/AKT pathway. SPNS2 may become a new diagnostic indicator and potential immunotherapeutic target for glioma.

Regulatory role of miRNAs in nasopharyngeal cancer involving PTEN/PI3K/AKT, TGFβ/SMAD, RAS/MAPK, Wnt/β-catenin and pRB-E2F signaling pathways: A review

MicroRNAs (miRNA) are small and conserved noncoding RNA molecules that regulate gene expression at the posttranscriptional level. These groups of RNAs are crucial in various cellular processes, especially in mediating disease pathogenesis, particularly cancer. The dysregulation of miRNAs was reported in many cancer types, including nasopharyngeal cancer (NPC), which is a malignant tumor of the nasopharynx. In this review, miRNAs involvement in crucial signaling pathways associated with NPC such as PTEN/PI3K/AKT, TGFβ/SMAD, RAS/MAPK, Wnt/β-catenin and pRB-E2F was investigated. miRNAs could function as tumor suppressor-miR or onco-miR in NPC profoundly influenced cell cycle, apoptosis, proliferation, migration, and metastasis. This comprehensive review of current literature provided a thorough profile of miRNAs and their interplay with the aforementioned signaling pathways in NPC. Understanding these molecular interactions could remarkably impact the diagnosis, prognosis, and therapeutic strategies for NPC.

PTEN-restoration abrogates brain colonisation and perivascular niche invasion by melanoma cells

BACKGROUND

Melanoma brain metastases (MBM) continue to be a significant clinical problem with limited treatment options. Highly invasive melanoma cells migrate along the vasculature and perivascular cells may contribute to residual disease and recurrence. PTEN loss and hyperactivation of AKT occur in MBM; however, a role for PTEN/AKT in perivascular invasion has not been described.

METHODS

We used in vivo intracranial injections of murine melanoma and bulk RNA sequencing of melanoma cells co-cultured with brain endothelial cells (brECs) to investigate brain colonisation and perivascular invasion.

RESULTS

We found that PTEN-null melanoma cells were highly efficient at colonising the perivascular niche relative to PTEN-expressing counterparts. PTEN re-expression (PTEN-RE) in melanoma cells significantly reduced brain colonisation and migration along the vasculature. We hypothesised this phenotype was mediated through vascular-induced TGFβ secretion, which drives AKT phosphorylation. Disabling TGFβ signalling in melanoma cells reduced colonisation and perivascular invasion; however, the introduction of constitutively active myristolated-AKT (myrAKT) restored overall tumour size but not perivascular invasion.

CONCLUSIONS

PTEN loss facilitates perivascular brain colonisation and invasion of melanoma. TGFβ-AKT signalling partially contributes to this phenotype, but further studies are needed to determine the complementary mechanisms that enable melanoma cells to both survive and spread along the brain vasculature.

The interplay of PTEN and AKT nexus in breast cancer: a molecular perspective

BACKGROUND

Breast cancer is a highly prevalent and life-threatening ailment that is commonly detected among the females. The downregulation of PTEN in breast cancer is associated with a poor prognosis, aggressive tumor type, and metastasis to lymph nodes, as it activates the pro-survival pathway PI3K/AKT, which is considered the ultimate proliferative pathway.

MATERIAL AND METHODS

The mRNA expression of PTEN and AKT genes was investigated using RT-qPCR and TaqMan primer probe chemistry. Moreover DNA was also isolated from the same tissue samples and exonic regions of both genes were amplified for mutational analysis. The proteins expression of PTEN and AKT from seven human breast cancer cell lines was checked through western blot experiments.

RESULT

The study revealed a decrease in PTEN expression in 73.3% of the samples, whereas an increase in AKT expression in 40% of samples was observed when compared to the distant normal breast tissue. Conversely, the remaining 60% of samples exhibited a decrease in AKT mRNA expression. There was no observed alteration in the genetic sequence of AKT and PTEN within the targeted amplified regions of breast cancer samples. The high levels of PTEN protein in T-47D and MDA-MB-453 resulted in a lower p-AKT. Two cell lines ZR-75-1 and MDA-MB-468 appeared to be PTEN negative on western blot but mRNA was detected on RT-qPCR.

CONCLUSION

In breast cancer the status/expression of PTEN & AKT at mRNA and protein level might be obliging in forecasting the path of disease progression, treatment and prognosis.

TRIM29 modulates proteins involved in PTEN/AKT/mTOR and JAK2/STAT3 signaling pathway and suppresses the progression of hepatocellular carcinoma

Tripartite motif-containing 29 (TRIM29), also known as the ataxia telangiectasia group D-complementing (ATDC) gene, has been reported to play an oncogenic or tumor suppressive role in developing different tumors. So far, its expression and biological functions in hepatocellular carcinoma (HCC) remain unclear. We investigated TRIM29 expression pattern in human HCC samples using quantitative RT-PCR and immunohistochemistry. Relationships between TRIM29 expression level, clinical prognostic indicators, overall survival (OS), and disease-free survival (DFS) were evaluated by Kaplan-Meier analysis and Cox proportional hazards model. A series of in vitro experiments and a xenograft tumor model were conducted to detect the functions of TRIM29 in HCC cells. RNA sequencing, western blotting, and immunochemical staining were performed to assess the molecular regulation of TRIM29 in HCC. We found that the mRNA and protein levels of TRIM29 were significantly reduced in HCC samples, compared with adjacent noncancerous tissues, and were negatively correlated with poor differentiation of HCC tissues. Survival analysis confirmed that lower TRIM29 expression significantly correlated with shorter OS and DFS of HCC patients. TRIM29 overexpression remarkably inhibited cell proliferation, migration, and EMT in HCC cells, whereas knockdown of TRIM29 reversed these effects. Moreover, deactivation of the PTEN/AKT/mTOR and JAK2/STAT3 pathways might be involved in the tumor suppressive role of TRIM29 in HCC. Our findings indicate that TRIM29 in HCC exerts its tumor suppressive effects through inhibition of the PTEN/AKT/mTOR and JAK2/STAT3 signaling pathways and may be used as a potential biomarker for survival in patients with HCC.

Cell-free DNA fragmentomics and second malignant neoplasm risk in patients with PTEN hamartoma tumor syndrome

Individuals with PTEN hamartoma tumor syndrome (PHTS) harbor pathogenic germline PTEN variants that confer a significantly increased lifetime risk of various organ-specific cancers including second primary malignant neoplasms (SMNs). Currently, there are no reliable biomarkers that can predict individual-level cancer risk. Despite the highly promising value of cell-free DNA (cfDNA) as a biomarker for underlying sporadic cancers, the utility of cfDNA in individuals with known cancer-associated germline variants and subclinical cancers remains poorly understood. We perform ultra-low-pass whole-genome sequencing (ULP-WGS) of cfDNA from plasma samples from patients with PHTS and cancer as well as those without cancer. Analysis of cfDNA reveals that patients with PHTS and SMNs have distinct cfDNA size distribution, aberrant genome-wide fragmentation, and differential fragment end motif frequencies. Our work provides evidence that cfDNA profiles may be used as a marker for SMN risk in patients with PHTS.

Tumorigenesis of basal muscle invasive bladder cancer was mediated by PTEN protein degradation resulting from SNHG1 upregulation

BACKGROUND

Phosphatase and tensin homolog deleted on chromosome ten (PTEN) serves as a powerful tumor suppressor, and has been found to be downregulated in human bladder cancer (BC) tissues. Despite this observation, the mechanisms contributing to PTEN's downregulation have remained elusive.

METHODS

We established targeted genes' knockdown or overexpressed cell lines to explore the mechanism how it drove the malignant transformation of urothelial cells or promoted anchorageindependent growth of human basal muscle invasive BC (BMIBC) cells. The mice model was used to validate the conclusion in vivo. The important findings were also extended to human studies.

RESULTS

In this study, we discovered that mice exposed to N-butyl-N-(4-hydroxybu-tyl)nitrosamine (BBN), a specific bladder chemical carcinogen, exhibited primary BMIBC accompanied by a pronounced reduction in PTEN protein expression in vivo. Utilizing a lncRNA deep sequencing high-throughput platform, along with gain- and loss-of-function analyses, we identified small nucleolar RNA host gene 1 (SNHG1) as a critical lncRNA that might drive the formation of primary BMIBCs in BBN-treated mice. Cell culture results further demonstrated that BBN exposure significantly induced SNHG1 in normal human bladder urothelial cell UROtsa. Notably, the ectopic expression of SNHG1 alone was sufficient to induce malignant transformation in human urothelial cells, while SNHG1 knockdown effectively inhibited anchorage-independent growth of human BMIBCs. Our detailed investigation revealed that SNHG1 overexpression led to PTEN protein degradation through its direct interaction with HUR. This interaction reduced HUR binding to ubiquitin-specific peptidase 8 (USP8) mRNA, causing degradation of USP8 mRNA and a subsequent decrease in USP8 protein expression. The downregulation of USP8, in turn, increased PTEN polyubiquitination and degradation, culminating in cell malignant transformation and BMIBC anchorageindependent growth. In vivo studies confirmed the downregulation of PTEN and USP8, as well as their positive correlations in both BBN-treated mouse bladder urothelium and tumor tissues of bladder cancer in nude mice.

CONCLUSIONS

Our findings, for the first time, demonstrate that overexpressed SNHG1 competes with USP8 for binding to HUR. This competition attenuates USP8 mRNA stability and protein expression, leading to PTEN protein degradation, consequently, this process drives urothelial cell malignant transformation and fosters BMIBC growth and primary BMIBC formation.