The PTEN/MMAC1 tumor suppressor phosphatase functions as a negative regulator of the phosphoinositide 3-kinase/Akt pathway

Effects of oridonin on sperm function and the PI3K/PDK1/AKT signaling pathway: Implications for reproductive toxicity

Oridonin, a natural terpenoid isolated from the leaves of Isodon rubescens (Hemsley) H.Hara, is widely used in oriental medicine for its anticancer properties across various cancer types. Despite its prevalent use, the toxic effects of oridonin on male reproduction, particularly its impact on sperm functions and the mechanisms involved, are not well understood. This study aimed to explore the effects and underlying mechanisms of oridonin on sperm functions. We initially treated Duroc boar spermatozoa with varying concentrations of oridonin (0, 5, 50, 75, 100, and 150 µM) and incubated them to induce capacitation. We then assessed cell viability and several sperm functions, including sperm motility and motion kinematics, capacitation status, and ATP levels. We also analyzed the expression levels of proteins associated with the phosphatidylinositol 3-kinase (PI3K)/phosphoinositide-dependent kinase-1 (PDK1)/protein kinase B (AKT) signaling pathway and phosphotyrosine proteins. Our results indicate that oridonin adversely affects most sperm functions in a dose-dependent manner. We observed significant decreases in AKT, p-AKT (Thr308), phosphatase and tensin homolog (PTEN), p-PDK1, and p-PI3K levels following oridonin treatment, alongside an abnormal increase in phosphotyrosine proteins. These findings suggest that oridonin may disrupt normal levels of tyrosine-phosphorylated proteins by inhibiting the PI3K/PDK1/AKT signaling pathway, which is crucial for cell proliferation, metabolism, and apoptosis, thus potentially harming sperm functions. Consequently, we recommend considering the reproductive toxicity of oridonin when using it as a therapeutic agent.

The roles of phosphorylation of signaling proteins in the prognosis of acute myeloid leukemia

Signaling pathways of Retinoblastoma (Rb) protein, Akt-kinase, and Erk-kinase (extracellular signal-regulated kinase) have an important role in the pathogenesis of acute myeloid leukemia. Constitutive activation of these proteins by phosphorylation contributes to cell survival by regulation of cell cycle, proliferation and proapoptotic signaling processes. According to previous data phosphorylated forms of these proteins represent a worse outcome for cancer patients. We investigated the presence of phosphorylated Rb (P-Rb), Akt (P-Akt) and Erk (P-Erk) proteins by Western blot technique using phospho-specific antibodies in bone marrow or peripheral blood samples of 69 AML patients, 36 patients with myelodysplastic syndrome (MDS) and 10 healthy volunteers. Expression level of PTEN (Phosphatase and tensin homolog) and PHLPP (PH domain and leucine-rich repeat Protein Phosphatase) phosphatases, the negative regulators of Akt kinase pathway were also examined. We tested the effect of these proteins on survival and on the correlation with known prognostic features in AML. We found 46.3% of AML patients had detectable P-Rb, 34.7% had P-Akt and 28.9% had P-Erk protein. 66.1% of patients expressing PTEN, 38.9% PHLPP, 37.2% both PTEN and PHLPP and 32.2% neither PTEN nor PHLPP phosphatases. Compared to nucleophosmin mutation (NPMc) negative samples P-Erk was significantly less in nucleophosmin mutated patients, P-Rb was significantly less in patients' group with more than 30 G/L peripheral leukocyte count by diagnosis. PHLPP was significantly present in FAB type M5. The expression of P-Rb represented significant better overall survival (OS), while P-Akt represented significantly worse event-free survival (EFS) in unfavorable cytogenetics patients. The presence of both PHLPP and PTEN phosphatases contributes to better OS and EFS, although the differences were not statistically significant. We confirmed significant positive correlation between P-Akt and PHLPP. Assessing the phosphorylation of Rb, Akt and Erk may define a subgroup of AML patients who would benefit especially from new targeted treatment options complemented the standard chemotherapy, and it may contribute to monitoring remission, relapse or progression of AML.

Interaction of circulating TGFβ regulatory miRNAs in different severity of diabetic kidney disease

AIMS

To explore the interaction of TGFβ regulatory microRNAs (miRNAs) with different severities of diabetic kidney disease (DKD).

METHODS

According to different UACR (30 and 300 mg/g), 436 subjects were included, and high glucose induced RMCs were cultured. Real-time PCR, ELISA, and automatic biochemical analysis were used to measure miRNAs, TGFβ1, and other biochemical indicators in serum and RMCs. Target genes of miRNA were predicted and visualised by bioinformatics.

RESULTS

HbA1c, TGFβ1, miR-217, and miR-224 in T2DM patients increased with UACR, while miR-192 and miR-216a decreased. Ln UACR was positively correlated with HbA1c, TGFβ1, miR-217, and miR-224, and negatively correlated with miR-192 and miR-216a. High glucose and TGFβ1 affected miRNAs and these miRNAs affected each other. The miRNA target genes mainly revolve around PTEN, PI3K/Akt, and MAPK signalling pathways.

CONCLUSION

TGFβ regulatory miRNAs and different severity of DKD have a potential interaction regulating fibrosis through PTEN, PI3K/Akt, and MAPK pathways.

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.

TC2N inhibits distant metastasis and stemness of breast cancer via blocking fatty acid synthesis

BACKGROUND

Tandem C2 domains, nuclear (TC2N) is a C2 domain-containing protein that belongs to the carboxyl-terminal type (C-type) tandem C2 protein family, and acts as an oncogenic driver in several cancers. Previously, we preliminarily reported that TC2N mediates the PI3K-Akt signaling pathway to inhibit tumor growth of breast cancer (BC) cells. Beyond that, its precise biological functions and detailed molecular mechanisms in BC development and progression are not fully understood.

METHODS

Tumor tissues of 212 BC patients were subjected to tissue microarray and further assessed the associations of TC2N expression with pathological parameters and FASN expression. The protein levels of TC2N and FASN in cell lines and tumor specimens were monitored by qRT-PCR, WB, immunofluorescence and immunohistochemistry. In vitro cell assays, in vivo nude mice model was used to assess the effect of TC2N ectopic expression on tumor metastasis and stemness of breast cancer cells. The downstream signaling pathway or target molecule of TC2N was mined using a combination of transcriptomics, proteomics and lipidomics, and the underlying mechanism was explored by WB and co-IP assays.

RESULTS

Here, we found that the expression of TC2N remarkedly silenced in metastatic and poorly differentiated tumors. Function-wide, TC2N strongly inhibits tumor metastasis and stem-like properties of BC via inhibition of fatty acid synthesis. Mechanism-wise, TC2N blocks neddylated PTEN-mediated FASN stabilization by a dual mechanism. The C2B domain is crucial for nuclear localization of TC2N, further consolidating the TRIM21-mediated ubiquitylation and degradation of FASN by competing with neddylated PTEN for binding to FASN in nucleus. On the other hand, cytoplasmic TC2N interacts with import proteins, thereby restraining nuclear import of PTEN to decrease neddylated PTEN level.

CONCLUSIONS

Altogether, we demonstrate a previously unidentified role and mechanism of TC2N in regulation of lipid metabolism and PTEN neddylation, providing a potential therapeutic target for anti-cancer.

PTEN is both an activator and a substrate of chaperone-mediated autophagy

PTEN is a crucial negative regulator of the INS/PI3K/AKT pathway and is one of the most commonly mutated tumor suppressors in cancer. Global overexpression (OE) of PTEN in mice shifts metabolism to favor oxidative phosphorylation over glycolysis, reduces fat mass, and extends the lifespan of both sexes. We demonstrate that PTEN regulates chaperone-mediated autophagy (CMA). Using cultured cells and mouse models, we show that PTEN OE enhances CMA, dependent upon PTEN's lipid phosphatase activity and AKT inactivation. Reciprocally, PTEN knockdown reduces CMA, which can be rescued by inhibiting class I PI3K or AKT. Both PTEN and CMA are negative regulators of glycolysis and lipid droplet formation. We show that suppression of glycolysis and lipid droplet formation downstream of PTEN OE depends on CMA activity. Finally, we show that PTEN protein levels are sensitive to CMA and that PTEN accumulates in lysosomes with elevated CMA. Collectively, these data suggest that CMA is both an effector and a regulator of PTEN.

ROCK2 Inhibition: A Futuristic Approach for the Management of Alzheimer's Disease

Neurons depend on mitochondrial functions for membrane excitability, neurotransmission, and plasticity.Mitochondrialdynamicsare important for neural cell maintenance. To maintain mitochondrial homeostasis, lysosomes remove dysfunctionalmitochondria through mitophagy. Mitophagy promotes mitochondrial turnover and prevents the accumulation of dysfunctional mitochondria. In many neurodegenerative diseases (NDDs), including Alzheimer's disease (AD), mitophagy is disrupted in neurons.Mitophagy is regulated by several proteins; recently,Rho-associated coiled-coil containing protein kinase 2 (ROCK2) has been suggested to negatively regulate the Parkin-dependent mitophagy pathway.Thus, ROCK2inhibitionmay bea promising therapyfor NDDs. This review summarizesthe mitophagy pathway, the role of ROCK2in Parkin-dependentmitophagyregulation,and mitophagy impairment in the pathology of AD. We further discuss different ROCK inhibitors (synthetic drugs, natural compounds,and genetherapy-based approaches)and examine their effects on triggering neuronal growth and neuroprotection in AD and other NDDs. This comprehensive overview of the role of ROCK in mitophagy inhibition provides a possible explanation for the significance of ROCK inhibitors in the therapeutic management of AD and other NDDs.

PARK7 deficiency inhibits fatty acid β-oxidation via PTEN to delay liver regeneration after hepatectomy

Background & aims

Transient regeneration–associated steatosis (TRAS) is a process of temporary hepatic lipid accumulation and is essential for liver regeneration by providing energy generated from fatty acid β‐oxidation, but the regulatory mechanism underlying TRAS remains unknown. Parkinsonism‐associated deglycase (Park7)/Dj1 is an important regulator involved in various liver diseases. In nonalcoholic fatty liver diseased mice, induced by a high‐fat diet, Park7 deficiency improves hepatic steatosis, but its role in liver regeneration remains unknown

Methods

Park7 knockout (Park7^−/−), hepatocyte‐specific Park7 knockout (Park7^△hep) and hepatocyte‐specific Park7‐Pten double knockout mice were subjected to 2/3 partial hepatectomy (PHx)

Results

Increased PARK7 expression was observed in the regenerating liver of mice at 36 and 48 h after PHx. Park7^−/− and Park7^△hep mice showed delayed liver regeneration and enhanced TRAS after PHx. PPARa, a key regulator of β‐oxidation, and carnitine palmitoyltransferase 1a (CPT1a), a rate‐limiting enzyme of β‐oxidation, had substantially decreased expression in the regenerating liver of Park7^△hep mice. Increased phosphatase and tensin homolog (PTEN) expression was observed in the liver of Park7^△hep mice, which might contribute to delayed liver regeneration in these mice because genomic depletion or pharmacological inhibition of PTEN restored the delayed liver regeneration by reversing the downregulation of PPARa and CPT1a and in turn accelerating the utilization of TRAS in the regenerating liver of Park7^△hep mice

Conclusion

Park7/Dj1 is a novel regulator of PTEN‐dependent fatty acid β‐oxidation, and increasing Park7 expression might be a promising strategy to promote liver regeneration.

Progerin modulates the IGF-1R/Akt signaling involved in aging

Progerin, a product of LMNA mutation, leads to multiple nuclear abnormalities in patients with Hutchinson-Gilford progeria syndrome (HGPS), a devastating premature aging disorder. Progerin also accumulates during physiological aging. Here, we demonstrate that impaired insulin-like growth factor 1 receptor (IGF-1R)/Akt signaling pathway results in severe growth retardation and premature aging in Zmpste24^-/- mice, a mouse model of progeria. Mechanistically, progerin mislocalizes outside of the nucleus, interacts with the IGF-1R, and down-regulates its expression, leading to inhibited mitochondrial respiration, retarded cell growth, and accelerated cellular senescence. Pharmacological treatment with the PTEN (phosphatase and tensin homolog deleted on chromosome 10) inhibitor bpV (HOpic) increases Akt activity and improves multiple abnormalities in Zmpste24-deficient mice. These findings provide previously unidentified insights into the role of progerin in regulating the IGF-1R/Akt signaling in HGPS and might be useful for treating LMNA-associated progeroid disorders.

Modeling prostate cancer: What does it take to build an ideal tumor model?

Prostate cancer is frequently characterized as a multifocal disease with great intratumoral heterogeneity as well as a high propensity to metastasize to bone. Consequently, modeling prostate tumor has remained a challenging task for researchers in this field. In the past decades, genomic advances have led to the identification of key molecular alterations in prostate cancer. Moreover, resistance towards second-generation androgen-deprivation therapy, namely abiraterone and enzalutamide has unveiled androgen receptor-independent diseases with distinctive histopathological and clinical features. In this review, we have critically evaluated the commonly used preclinical models of prostate cancer with respect to their capability of recapitulating the key genomic alterations, histopathological features and bone metastatic potential of human prostate tumors. In addition, we have also discussed the potential use of the emerging organoid models in prostate cancer research, which possess clear advantages over the commonly used preclinical tumor models. We anticipate that no single model can faithfully recapitulate the complexity of prostate cancer, and thus, propose the use of a cost- and time-efficient integrated tumor modeling approach for future prostate cancer investigations.

Retention of higher fertility depending on ovarian follicle reserve in cystine-glutamate transporter gene-deficient mice

The cystine-glutamate transporter (xCT) is responsible for the transport of cystine into cells. We recently found that xCT-deficient (xCTKO) aged mice maintained a higher rate of ovulation and ovarian weight compared with wild-type (WT) mice. It has been reported that a xCT deficiency in cultured cells induces autophagy through the suppression of mTOR survival pathways. We have previously reported that starvation in neonatal mice increases the number of primordial follicles with concomitant autophagy activation. Therefore, we investigated age-related changes in follicle reserve and fertility in xCTKO mice and clarified whether the PI3K/AKT/mTOR signaling pathway contributes to this. The numbers of offspring in the xCTKO mice aged 10 and 12 months were significantly higher than those in the WT mice. The primordial follicle numbers in xCTKO neonatal mice tended to be higher than WT mice during all times evaluated. In contrast, the primary follicle number was significantly lower in the xCTKO mice at 60 h after birth. The expression of p-AKT, which promotes follicle development, was significantly lower in xCTKO mice than that in WT mice, whereas the expression ratios of LC3-II/LC3-I were significantly higher. The xCTKO mice had significantly more primordial follicles than WT mice at 2 months of age and showed a similar trend at 13-15 months of age. These results suggest that the maintenance of fertility in aged xCTKO mice can be attributed to high follicle reserve after puberty by suppression of follicle activation during the neonatal period.

Reactive oxygen species (ROS) in cancer pathogenesis and therapy: An update on the role of ROS in anticancer action of benzophenanthridine alkaloids

Reactive oxygen species play crucial role in biological homeostasis and pathogenesis of human diseases including cancer. In this line, now it has become evident that ROS level/concentration is a major factor in the growth, progression and stemness of cancer cells. Moreover, cancer cells maintain a delicate balance between ROS and antioxidants to promote pathogenesis and clinical challenges via targeting a battery of signaling pathways converging to cancer hallmarks. Recent findings also entail the therapeutic importance of ROS for the better clinical outcomes in cancer patients as they induce apoptosis and autophagy. Moreover, poor clinical outcomes associated with cancer therapies are the major challenge and use of natural products have been vital in attenuation of these challenges due to their multitargeting potential with less adverse effects. In fact, most available drugs are derived from natural resources, either directly or indirectly and available evidence show the clinical importance of natural products in the management of various diseases, including cancer. ROS play a critical role in the anticancer actions of natural products, particularly phytochemicals. Benzophenanthridine alkaloids of the benzyl isoquinoline family of alkaloids, such as sanguinarine, possess several pharmacological properties and are thus being studied for the treatment of different human diseases, including cancer. In this article, we review recent findings, on how benzophenanthridine alkaloid-induced ROS play a critical role in the attenuation of pathological changes and stemness features associated with human cancers. In addition, we highlight the role of ROS in benzophenanthridine alkaloid-mediated activation of the signaling pathway associated with cancer cell apoptosis and autophagy.

PTEN hamartoma tumour syndrome: what happens when there is no PTEN germline mutation?

Hereditary cancer syndromes represent ~10% of all incident cancers. It is important to identify individuals having these disorders because, unlike patients with sporadic cancer, these patients require specialised life-long care, with implications for their families. Importantly, the identification of alterations in cancer-predisposing genes facilitates gene-informed molecular diagnosis, cancer risk assessment and gene-specific clinical management. Moreover, knowledge about gene function in the inherited cancers offers insights towards biological processes pertinent to the more common sporadic cancers. Conversely, without a known gene, clinical management is less precise, and it is impossible to offer predictive testing of family members. PTEN hamartoma tumour syndrome (PHTS) is an umbrella term encompassing four overgrowth and cancer predisposition disorders associated with germline PTEN mutations. With time, it became evident that only a finite subset of individuals with PHTS-associated phenotypes harbour germline PTEN mutations. Therefore, non-PTEN aetiologies exist in PTEN wildtype patients. Indeed, gene discovery efforts over the last decade elucidated multiple candidate cancer predisposition genes. While a subset of genes (e.g. AKT1, PIK3CA) are biologically plausible as being key effectors within the PTEN signalling cascade, other genes required meticulous functional interrogation to explain their contribution to PHTS-related phenotypes. Collectively, the extensive phenotypic heterogeneity of the clinical syndromes typically united by PTEN is reflected by the genetic heterogeneity revealed through gene discovery. Validating these gene discoveries is critical because, while PTEN wildtype patients can be diagnosed clinically, they do not have the benefit of specific gene-informed risk assessment and subsequent management.

Tartrate-resistant acid phosphatase type 5/ACP5 promotes cell cycle entry of 3T3-L1 preadipocytes by increasing IGF-1/Akt signaling

Tartrate-resistant acid phosphatase (TRAP, encoded by ACP5)-overexpressing mice exhibit hyperplastic obesity. As the molecular mechanism remains elusive, the aims were to characterize the effect of TRAP on preadipocyte proliferation. We investigated cell cycle entry and signal transduction, that is, insulin-like growth factor 1 (IGF-1)/ insulin receptor substrate 1 (IRS-1) and the Akt signaling pathways, in 3T3-L1 preadipocytes treated with the TRAP 5a isoform. Results show that TRAP 5a increases S-phase entry. TRAP 5a stimulation increases IGF-1 mRNA and IRS-1 activation, indicative of insulin-like growth factor 1 receptor (IGF1R) activation. Furthermore, TRAP 5a stimulation resulted in Akt signaling pathway activation and subsequent increased nuclear translocation of β-catenin. In conclusion, TRAP 5a increases proliferation of preadipocytes in a dose-dependent fashion by promoting entry into S-phase. Part of this effect is likely due to increased IGF-1 signaling through the Akt signaling pathway.

Cooperation between liver-specific mutations of pten and tp53 genetically induces hepatocarcinogenesis in zebrafish

BACKGROUND

Liver cancer, mainly hepatocellular carcinoma, is one of the deadliest cancers worldwide and has a poor prognosis due to insufficient understanding of hepatocarcinogenesis. Previous studies have revealed that the mutations in PTEN and TP53 are the two most common genetic events in hepatocarcinogenesis. Here, we illustrated the crosstalk between aberrant Pten and Tp53 pathways during hepatocarcinogenesis in zebrafish.

METHODS

We used the CRISPR/Cas9 system to establish several transgenic zebrafish lines with single or double tissue-specific mutations of pten and tp53 to genetically induce liver tumorigenesis. Next, the morphological and histological determination were performed to investigate the roles of Pten and Tp53 signalling pathways in hepatocarcinogenesis in zebrafish.

RESULTS

We demonstrated that Pten loss alone induces hepatocarcinogenesis with only low efficiency, whereas single mutation of tp53 failed to induce tumour formation in liver tissue in zebrafish. Moreover, zebrafish with double mutations of pten and tp53 exhibits a much higher tumour incidence, higher-grade histology, and a shorter survival time than single-mutant zebrafish, indicating that these two signalling pathways play important roles in dynamic biological events critical for the initiation and progression of hepatocarcinogenesis in zebrafish. Further histological and pathological analyses showed significant similarity between the tumours generated from liver tissues of zebrafish and humans. Furthermore, the treatment with MK-2206, a specific Akt inhibitor, effectively suppressed hepatocarcinogenesis in zebrafish.

CONCLUSION

Our findings will offer a preclinical animal model for genetically investigating hepatocarcinogenesis and provide a useful platform for high-throughput anticancer drug screening.

Activation of autophagy in early neonatal mice increases primordial follicle number and improves lifelong fertility†

The number of stockpiled primordial follicles is thought to be responsible for the fate of female fertility and reproductive lifetime. We previously reported that starvation in nonsuckling early neonatal mice increases the number of primordial follicles with concomitant autophagy activation, suggesting that autophagy may accelerate the formation of primordial follicles. In this study, we attempted to upregulate the numbers of primordial follicles by administering an autophagy inducer and evaluated the progress of primordial follicle formation and their fertility during the life of the mice. To induce autophagy, mice were intraperitoneally injected with the Tat-beclin1 D-11 peptide (0.02 mg/g body weight) at 6-54 h or 60-84 h after birth. In animals that received Tat-beclin 1 D-11 by 54 h after birth, the primordial follicle numbers were significantly increased compared with the control group at 60 h. The ratio of expressed LC3-II/LC3-I proteins was also significantly greater. The numbers of littermates from pregnant females that had been treated with Tat-beclin 1 D-11 were maintained at remarkably greater levels until 10 months old. These results were supported by an abundance of primordial follicles at even 13-15 months old.

Electric signals counterbalanced posterior vs anterior PTEN signaling in directed migration of Dictyostelium

Background

Cells show directed migration response to electric signals, namely electrotaxis or galvanotaxis. PI3K and PTEN jointly play counterbalancing roles in this event via a bilateral regulation of PIP3 signaling. PI3K has been proved essential in anterior signaling of electrotaxing cells, whilst the role of PTEN remains elusive.

Methods

Dictyostelium cells with different genetic backgrounds were treated with direct current electric signals to investigate the genetic regulation of electrotaxis.

Results

We demonstrated that electric signals promoted PTEN phosphatase activity and asymmetrical translocation to the posterior plasma membrane of the electrotaxing cells. Electric stimulation produced a similar but delayed rear redistribution of myosin II, immediately before electrotaxis started. Actin polymerization is required for the asymmetric membrane translocation of PTEN and myosin. PTEN signaling is also responsible for the asymmetric anterior redistribution of PIP3/F-actin, and a biased redistribution of pseudopod protrusion in the forwarding direction of electrotaxing cells.

Conclusions

PTEN controls electrotaxis by coordinately regulating asymmetric redistribution of myosin to the posterior, and PIP3/F-actin to the anterior region of the directed migration cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-021-00580-x.

PTEN somatic mutations contribute to spectrum of cerebral overgrowth

Phosphatase and tensin homolog (PTEN) regulates cell growth and survival through inhibition of the mammalian target of rapamycin (MTOR) signaling pathway. Germline genetic variation of PTEN is associated with autism, macrocephaly, and PTEN hamartoma tumor syndromes (PHTS). The effect of developmental PTEN somatic mutations on nervous system phenotypes is not well understood, although brain somatic mosaicism of MTOR pathway genes is an emerging cause of cortical dysplasia and epilepsy in the pediatric population. Here we report two somatic variants of PTEN affecting a single patient presenting with intractable epilepsy and hemimegalencephaly that varied in clinical severity throughout the left cerebral hemisphere. High-throughput sequencing analysis of affected brain tissue identified two somatic variants in PTEN. The first variant was present in multiple cell lineages throughout the entire hemisphere and associated with mild cerebral overgrowth. The second variant was restricted to posterior brain regions and affected the opposite PTEN allele, resulting in a segmental region of more severe malformation, and the only neurons in which it was found by single-nuclei RNA-seq had a unique disease-related expression profile. This study reveals brain mosaicism of PTEN as a disease mechanism of hemimegalencephaly and furthermore demonstrates the varying effects of single- or bi-allelic disruption of PTEN on cortical phenotypes.

Propranolol Participates in the Treatment of Infantile Hemangioma by Inhibiting HUVECs Proliferation, Migration, Invasion, and Tube Formation

OBJECTIVE

Infantile hemangiomas (IHs) are the most common benign tumors in infancy. The purpose of this study was to study the effects of propranolol on the function of human umbilical vein endothelial cells (HUVECs), in order to preliminarily elucidate the mechanism of propranolol in the treatment of IHs.

METHODS

HUVECs were treated with different concentrations of propranolol (30 μM, 60 μM, 90 μM, and 120 μM) with or without VEGF. Their proliferation, migration, invasion, adhesion, and tube formation ability were tested by using CCK-8, wound healing assay, transwell, cell adhesion assay, and tube formation assay. The expressions of HUVECs angiogenesis signaling molecules pERK/ERK, pAKT/AKT, p-mTOR/mTOR, and pFAK/FAK were detected by Western blot.

RESULTS

Compared with the control group, propranolol could significantly inhibit the proliferation, migration, invasion, adhesion, and tube formation of HUVECs. Further studies showed that it could not only inhibit the migration, invasion, and tube formation ability of HUVECs after VEGF induction but also inhibit the phosphorylated protein expressions of angiogenesis-related signaling molecules like AKT, mTOR, ERK, and FAK in HUVECs, with a concentration-dependent inhibitory effect.

CONCLUSION

Propranolol can inhibit the proliferation, migration, invasion, adhesion, and tube formation of hemangioma endothelial cells; block VEGF-mediated angiogenesis signaling pathway; suppress the expressions of downstream angiogenesis-related signaling molecules; and ultimately achieve the effect of treatment of IHs.

Glucose and cholesterol induce abnormal cell divisions via DAF-12 and MPK-1 in C. elegans

People exposed to starvation have a high risk of developing cancer later in life, and prior studies have shown these individuals have high insulin and cholesterol levels and are sensitive to glucose. Using C. elegans as a model, we found that glucose and cholesterol can promote survival and cause starved L1 diapause worms to undergo abnormal neuronal cell divisions. Starvation has also been shown to promote long-term survival; however, we found that the functions of glucose and cholesterol in relation to these cell divisions are distinct from their effects on survival. We demonstrate that glucose functions in a DAF-16/FOXO-independent IIS pathway to activate the MAPK ontogenetic signaling to induce neuronal Q-cell divisions, and cholesterol works through DAF-12/steroidogenic pathways to promote these cell divisions. daf-12 and mpk-1/MAPK mutants suppress the function of glucose and cholesterol in these divisions, and a fully functioning dpMPK-1 requires the steroid hormone receptor DAF-12 for these divisions to occur. These afflictions also can be passed on to the immediate progeny. This work indicates a possible link between glucose and cholesterol in starved animals and an increased risk of cancer.

Shank-associated RH domain interactor signaling in tumorigenesis

Shank-associated RH domain interactor (SHARPIN) is a component of the linear ubiquitin chain activation complex, which is essential for p53 signaling and inflammation. Previous studies have demonstrated that SHARPIN functions in tumor cell survival, growth, invasion and tumorigenesis. These functions include the regulation of p53 proteins via poly-ubiquitination, interaction with a type II protein arginine methyltransferase 5 in melanoma cells, modulating ras-associated protein-1 through p38 and c-Jun N-terminal kinases/c-Jun signaling, and mediating phosphoinositide 3-kinase/AKT signaling via phosphatase and tensin homologue deleted on chromosome 10. Hence, SHARPIN not only participates in the inflammatory response but also serves a critical role in tumor cells. The present review summarizes the biological functions of the absence or presence of SHARPIN with regard to activating the canonical NF-κB signaling pathway and the effects on p53 and other signaling pathways for the modulation of tumorigenesis. Therefore, this review provides insight into the underlying role and mechanisms of SHARPIN in tumorigenesis, as well as its potential application in cancer therapy.

Acetyltanshinone IIA is more potent than lapatinib in inhibiting cell growth and degrading HER2 protein in drug-resistant HER2-positive breast cancer cells

High expression of human epidermal factor receptor 2 (HER2) is directly related to tumor progression, malignancy and drug resistance in HER2-positive breast cancer (HER2-PBC). The major limitation of current anti-HER2 therapies is that they cannot reduce the levels of HER2 protein. Here, we investigated the effect of acetyltanshinone IIA (ATA) in lapatinib-resistant HER2-PBC cells. Our data showed that ATA exhibited more potent effects than lapatinib against drug-resistant HER2-PBC cells in terms of (1) inhibiting cell growth, (2) reducing phosphorylated and total HER2 levels, (3) inhibiting tumor xenograft growth in nude mice, and (4) reducing HER2 protein levels in tumor xenografts. A mechanistic study revealed that ATA promoted HER2 degradation via increasing c-Cbl and CHIP-mediated HER2 ubiquitination and subsequent HER2 degradation by the proteasome or lysosome. ATA also reduced the levels of other tyrosine kinase receptors (TKRs), such as HER3, IGF-1R and MET, in lapatinib-resistant cells. Our findings suggest that direct degradation of HER2 and other TKRs can be an effective strategy for combatting drug resistance. They also indicate the potential utilization of ATA in treating breast cancer that is resistant or nonresponsive to current HER2-targeted therapies.

PTEN in Hereditary and Sporadic Cancer

Germline pathogenic phosphatase and tensin homolog (PTEN) mutations cause PTEN hamartoma tumor syndrome (PHTS), characterized by various benign and malignant tumors of the thyroid, breast, endometrium, and other organs. Patients with PHTS may present with other clinical features such as macrocephaly, intestinal polyposis, cognitive changes, and pathognomonic skin changes. Clinically, deregulation of PTEN function is implicated in other human diseases in addition to many types of human cancer. PTEN is an important phosphatase that counteracts one of the most critical cancer pathways: the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathways. Although PTEN can dephosphorylate lipids and proteins, it also has functions independent of phosphatase activity in normal and pathological states. It is positively and negatively regulated at the transcriptional level as well as posttranslationally by phosphorylation, ubiquitylation, oxidation, and acetylation. Although most of its tumor-suppressor activity is likely to be caused by lipid dephosphorylation at the plasma membrane, PTEN also resides in the cytoplasm and nucleus, and its subcellular distribution is under strict control. In this review, we highlight our current knowledge of PTEN function and recent discoveries in understanding PTEN function regulation and how this can be exploited therapeutically for cancer treatment.

Genome sequencing analysis of a family with a child displaying severe abdominal distention and recurrent hypoglycemia

BACKGROUND

Germline mutations in PTEN are associated with the PTEN hamartoma tumor syndrome (PHTS), an umbrella term used to describe a spectrum of autosomal-dominant disorders characterized by variable phenotypic manifestations associated with cell or tissue overgrowth. We report a boy who developed severe progressive abdominal distention due to a dramatic adipose mass from the age of 7 months and developed recurrent hypoinsulinemic hypoglycemia that led to seizures at the age of 4 years.

METHODS

Trio-based whole-genome sequencing was performed by using blood DNA from the child and his parents. The possible pathogenic variants were verified by Sanger sequencing. Functional characterization of the identified variant was completed by western blot.

RESULTS

The child inherited a single-nucleotide deletion NM_000314.6:c.849delA (p.Glu284Argfs) in the tumor suppressor gene PTEN from his father. The paternal family members have a history of cancer. It is conceivable that PTEN loss-of-function induced the adipose tumor growth and hypoglycemia, although the proband did not meet the usual diagnosis criteria of Cowden syndrome or Bannayan-Riley-Ruvalcaba syndrome that are characterized by germline mutations of PTEN.

CONCLUSION

This case underlines the variability of phenotypes associated with PTEN germline mutations and provides useful information for diagnosis and genetic counseling of PTEN-related diseases for pediatric patients.

ROCK inhibitors upregulate the neuroprotective Parkin-mediated mitophagy pathway

The accumulation of damaged mitochondria causes the death of dopaminergic neurons. The Parkin-mediated mitophagy pathway functions to remove these mitochondria from cells. Targeting this pathway represents a therapeutic strategy for several neurodegenerative diseases, most notably Parkinson's disease. We describe a discovery pipeline to identify small molecules that increase Parkin recruitment to damaged mitochondria and ensuing mitophagy. We show that ROCK inhibitors promote the activity of this pathway by increasing the recruitment of HK2, a positive regulator of Parkin, to mitochondria. This leads to the increased targeting of mitochondria to lysosomes and removal of damaged mitochondria from cells. Furthermore, ROCK inhibitors demonstrate neuroprotective effects in flies subjected to paraquat, a parkinsonian toxin that induces mitochondrial damage. Importantly, parkin and rok are required for these effects, revealing a signaling axis which controls Parkin-mediated mitophagy that may be exploited for the development of Parkinson's disease therapeutics.

Multifaceted Regulation of PTEN Subcellular Distributions and Biological Functions

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor gene frequently found to be inactivated in over 30% of human cancers. PTEN encodes a 54-kDa lipid phosphatase that serves as a gatekeeper of the phosphoinositide 3-kinase pathway involved in the promotion of multiple pro-tumorigenic phenotypes. Although the PTEN protein plays a pivotal role in carcinogenesis, cumulative evidence has implicated it as a key signaling molecule in several other diseases as well, such as diabetes, Alzheimer's disease, and autism spectrum disorders. This finding suggests that diverse cell types, especially differentiated cells, express PTEN. At the cellular level, PTEN is widely distributed in all subcellular compartments and organelles. Surprisingly, the cytoplasmic compartment, not the plasma membrane, is the predominant subcellular location of PTEN. More recently, the finding of a secreted 'long' isoform of PTEN and the presence of PTEN in the cell nucleus further revealed unexpected biological functions of this multifaceted molecule. At the regulatory level, PTEN activity, stability, and subcellular distribution are modulated by a fascinating array of post-translational modification events, including phosphorylation, ubiquitination, and sumoylation. Dysregulation of these regulatory mechanisms has been observed in various human diseases. In this review, we provide an up-to-date overview of the knowledge gained in the last decade on how different functional domains of PTEN regulate its biological functions, with special emphasis on its subcellular distribution. This review also highlights the findings of published studies that have reported how mutational alterations in specific PTEN domains can lead to pathogenesis in humans.

Curcumin Induces Apoptotic Cell Death via Inhibition of PI3-Kinase/AKT Pathway in B-Precursor Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a significant cancer of children resulting from the clonal proliferation of lymphoid precursors with arrested maturation. Although chemotherapeutic approaches have been achieving successful remission for the majority of cases of childhood ALL, development of resistance to chemotherapy has been observed. Thus, new therapeutic approaches are required to improve patient's prognosis. Therefore, we investigated the anticancer potential of curcumin in ALL. We tested a panel of B-precursor ALL (B-Pre-ALL) cell lines with various translocations after treatment with different doses of curcumin. Curcumin suppresses the viability in a concentration-dependent manner in 697, REH, SupB15, and RS4;11 cells (doses from 0 to 80 μM). Curcumin induces apoptosis in B-Pre-ALL cell lines via activation of caspase-8 and truncation of BID. Curcumin treatment increased the ratio of Bax/Bcl-2 and resulted in a leaky mitochondrial membrane that led to the discharge of cytochrome c from the mitochondria to the cytoplasm, the activation of caspase 3 and the cleavage of PARP. Curcumin treatment of B-Pre-ALL cell lines induced a dephosphorylation of the constitutive phosphorylated AKT/PKB and a down-regulation of the expression of cIAP1, and XIAP. Moreover, curcumin mediates its anticancer activity by the generation of reactive oxygen species. Finally, the suboptimal doses of curcumin potentiated the anticancer activity of cisplatin. Altogether, these results suggest an important therapeutic role of curcumin, acting as a growth suppressor of B-Pre-ALL by apoptosis via inactivation of AKT/PKB and down-regulation of IAPs and activation of intrinsic apoptotic pathway via generation of Reactive Oxygen Species (ROS). Our interesting findings raise the possibility of considering curcumin as a potential therapeutic agent for the treatment of B-Pre-ALL.

Identification of TC2N as a novel promising suppressor of PI3K-AKT signaling in breast cancer

Although TC2N has proven to be an oncogene in lung cancer, its biological function and molecular mechanisms in other cancer still remains unclear. Here, we investigate in breast cancer that TC2N expression is sharply overexpressed in breast cancer specimens compared with normal breast specimens, and the low TC2N expression was associated with advanced stage, lymphatic metastasis, larger tumors and shorter survival time. Upregulation of TC2N significantly restrains breast cancer cell proliferation in vitro and tumor growth in vivo. Mechanistically, TC2N blocks AKT signaling in a PI3K dependent and independent way through weakening the interaction between ALK and p55γ or inhibiting the binding of EBP1 and AKT. To sum up, these results unmask an ambivalent role of TC2N in cancer, providing a promising inhibitor for PI3K-AKT signaling.

The transcriptional factors HIF-1 and HIF-2 and their novel inhibitors in cancer therapy

Introduction: Hypoxia is one of the intrinsic features of solid tumors, and it is always associated with aggressive phenotypes, including resistance to radiation and chemotherapy, metastasis, and poor patient prognosis. Hypoxia manifests these unfavorable effects through activation of a family of transcription factors, Hypoxia-inducible factors (HIFs) play a pivotal role in the adaptation of tumor cells to hypoxic and nutrient-deprived conditions by upregulating the transcription of several pro-oncogenic genes. Several advanced human cancers share HIFs activation as a final common pathway. Areas covered: This review highlights the role and regulation of the HIF-1/2 in cancers and alludes on the biological complexity and redundancy of HIF-1/2 regulation. Moreover, this review summarizes recent insights into the therapeutic approaches targeting the HIF-1/2 pathway. Expert opinion: More studies are needed to unravel the extensive complexity of HIFs regulation and to develop more precise anticancer treatments. Inclusion of HIF-1/2 inhibitors to the current chemotherapy regimens has been proven advantageous in numerous reported preclinical studies. The combination therapy ideally should be personalized based on the type of mutations involved in the specific cancers, and it might be better to include two drugs that inhibit HIF-1/2 activity by synergistic molecular mechanisms.

PTEN-opathies: from biological insights to evidence-based precision medicine

The tumor suppressor phosphatase and tensin homolog (PTEN) classically counteracts the PI3K/AKT/mTOR signaling cascade. Germline pathogenic PTEN mutations cause PTEN hamartoma tumor syndrome (PHTS), featuring various benign and malignant tumors, as well as neurodevelopmental disorders such as autism spectrum disorder. Germline and somatic mosaic mutations in genes encoding components of the PI3K/AKT/mTOR pathway downstream of PTEN predispose to syndromes with partially overlapping clinical features, termed the "PTEN-opathies." Experimental models of PTEN pathway disruption uncover the molecular and cellular processes influencing clinical phenotypic manifestations. Such insights not only teach us about biological mechanisms in states of health and disease, but also enable more accurate gene-informed cancer risk assessment, medical management, and targeted therapeutics. Hence, the PTEN-opathies serve as a prototype for bedside to bench, and back to the bedside, practice of evidence-based precision medicine.

PTEN-GSK3β-MOB1 axis controls neurite outgrowth in vitro and in vivo

Mps One binder 1 (MOB1) is a core component of NDR/LATS kinase and a positive regulator of the Hippo signaling pathway. However, its role in neurite outgrowth still remains to be clarified. Here, we confirmed, for the first time, that MOB1 promoted neurite outgrowth and was involved in functional recovery after spinal cord injury (SCI) in mice. Mechanistically, we found that MOB1 stability was regulated by the PTEN-GSK3β axis. The MOB1 protein was significantly up-regulated in PTEN-knockdown neuronal cells. This effect was dependent on the lipid phosphatase activity of PTEN. Moreover, MOB1 was found to be a novel substrate for GSK3β that is phosphorylated on serine 146 and degraded via the ubiquitin-proteasome system (UPS). Finally, in vivo lentiviral-mediated silencing of PTEN promoted neurite outgrowth and functional recovery after SCI and this effect was reversed by down-regulation of MOB1. Taken together, this study provided mechanistic insight into how MOB1 acts as a novel and a necessary regulator in PTEN-GSK3β axis that controls neurite outgrowth after SCI.

65 YEARS OF THE DOUBLE HELIX: One gene, many endocrine and metabolic syndromes: PTEN-opathies and precision medicine

An average of 10% of all cancers (range 1-40%) are caused by heritable mutations and over the years have become powerful models for precision medicine practice. Furthermore, such cancer predisposition genes for seemingly rare syndromes have turned out to help explain mechanisms of sporadic carcinogenesis and often inform normal development. The tumor suppressor PTEN encodes a ubiquitously expressed phosphatase that counteracts the PI3K/AKT/mTOR cascade - one of the most critical growth-promoting signaling pathways. Clinically, individuals with germline PTEN mutations have diverse phenotypes and fall under the umbrella term PTEN hamartoma tumor syndrome (PHTS). PHTS encompasses four clinically distinct allelic overgrowth syndromes, namely Cowden, Bannayan-Riley-Ruvalcaba, Proteus and Proteus-like syndromes. Relatedly, mutations in other genes encoding components of the PI3K/AKT/mTOR pathway downstream of PTEN also predispose patients to partially overlapping clinical manifestations, with similar effects as PTEN malfunction. We refer to these syndromes as 'PTEN-opathies.' As a tumor suppressor and key regulator of normal development, PTEN dysfunction can cause a spectrum of phenotypes including benign overgrowths, malignancies, metabolic and neurodevelopmental disorders. Relevant to clinical practice, the identification of PTEN mutations in patients not only establishes a PHTS molecular diagnosis, but also informs on more accurate cancer risk assessment and medical management of those patients and affected family members. Importantly, timely diagnosis is key, as early recognition allows for preventative measures such as high-risk screening and surveillance even prior to cancer onset. This review highlights the translational impact that the discovery of PTEN has had on the diagnosis, management and treatment of PHTS.

Combination Therapies Using Metformin and/or Valproic Acid in Prostate Cancer: Possible Mechanistic Interactions

Prostate cancer (PCa) is the most frequent cancer in men. The evolution from local PCa to castration-resistant PCa, an end-stage of disease, is often associated with changes in genes such as p53, androgen receptor, PTEN, and ETS gene fusion products. Evidence is accumulating that repurposing of metformin (MET) and valproic acid (VPA) either when used alone, or in combination, with another therapy, could potentially play a role in slowing down PCa progression. This review provides an overview of the application of MET and VPA, both alone and in combination with other drugs for PCa treatment, correlates the responses to these drugs with common molecular changes in PCa, and then describes the potential for combined MET and VPA as a systemic therapy for prostate cancer, based on potential interacting mechanisms.

Dynamics and structural stability effects of germline PTEN mutations associated with cancer versus autism phenotypes

Individuals with germline mutations in the tumor suppressor gene phosphatase and tensin homolog (PTEN), irrespective of clinical presentation, are diagnosed with PTEN hamartoma tumor syndrome (PHTS). PHTS confers a high risk of breast, thyroid, and other cancers or autism spectrum disorder (ASD) with macrocephaly. It remains unclear why mutations in one gene can lead to seemingly disparate phenotypes. Thus, we sought to identify differences in ASD vs. cancer-associated germline PTEN missense mutations by investigating putative structural effects induced by each mutation. We utilized a theoretical computational approach combining in silico structural analysis and molecular dynamics (MD) to interrogate 17 selected mutations from our patient population: six mutations were observed in patients with ASD (only), six mutations in patients with PHTS-associated cancer (only), four mutations shared across both phenotypes, and one mutation with both ASD and cancer. We demonstrate structural stability changes where all six cancer-associated mutations showed a global decrease in structural stability and increased dynamics across the domain interface with a proclivity to unfold, mediating a closed (inactive) active site. In contrast, five of the six ASD-associated mutations showed localized destabilization that contribute to the partial opening of the active site. Our results lend insight into distinctive structural effects of germline PTEN mutations associated with PTEN-ASD vs. those associated with PTEN-cancer, potentially aiding in identification of the shared and separate molecular features that contribute to autism or cancer, thus, providing a deeper understanding of genotype-phenotype relationships for germline PTEN mutations.

PTEN deficiency promotes pathological vascular remodeling of human coronary arteries

Phosphatase and tensin homolog (PTEN) is an essential regulator of the differentiated vascular smooth muscle cell (SMC) phenotype. Our goal was to establish that PTEN loss promotes SMC dedifferentiation and pathological vascular remodeling in human atherosclerotic coronary arteries and nonatherosclerotic coronary arteries exposed to continuous-flow left ventricular assist devices (CF-LVADs). Arteries were categorized as nonatherosclerotic hyperplasia (NAH), atherosclerotic hyperplasia (AH), or complex plaque (CP). NAH coronary arteries from CF-LVAD patients were compared to NAH coronaries from non-LVAD patients. Intimal PTEN and SMC contractile protein expression was reduced compared with the media in arteries with NAH, AH, or CP. Compared with NAH, PTEN and SMC contractile protein expression was reduced in the media and intima of arteries with AH and CP. NAH arteries from CF-LVAD patients showed marked vascular remodeling and reduced PTEN and α-smooth muscle actin (αSMA) in medial SMCs compared with arteries from non-LVAD patients; this correlated with increased medial collagen deposition. Mechanistically, compared with ApoE^–/– mice, SMC-specific PTEN-null/ApoE^–/– double-knockout mice exhibited accelerated atherosclerosis progression and increased vascular fibrosis. By microarray and validated quantitative RT-PCR analysis, SMC PTEN deficiency promotes a global upregulation of proinflammatory and profibrotic genes. We propose that PTEN is an antiinflammatory, antifibrotic target that functions to maintain SMC differentiation. SMC loss of PTEN results in pathological vascular remodeling of human arteries.

PTEN loss correlates with dedifferentiation of smooth muscle cells of human coronary arteries affected with atherosclerosis or exposed to continuous-flow left ventricular assist devices.

MYOD and HAND transcription factors have conserved recognition sites in mTOR promoter: insights from in silico analysis

mTOR regulates multiple cellular processes that are critical for proper maintenance of cell growth and development. However, mechanisms and factors responsible for transcriptional regulation of mTOR are partially known. To identify different transcription factor binding sites in promoter region of mTOR, we performed in silico phylogenetic foot printing analysis of diverse set of human orthologs. Phylogenetic tree for the orthologs was generated to establish the evolutionary relationships among them. Conserved binding sites among the species were predicted by tool MEME. The predicted conserved sites were further analyzed for binding of transcription factors by MatInspector program. Predicted TFs were then integrated with known physical interactions and coexpression data to decipher the important transcriptional regulators of mTOR signaling. Our study suggests that motifs AGGCGGG (+ 15 to + 21) and GGCGGC (+ 60 to + 65) are highly conserved across the species and are recognition sequence for HAND and MYOD transcription factors, respectively. Also these two transcription factors show direct physical interaction in protein-protein interaction map, indicating their regulatory role on expression of mTOR for control of myogenesis. Our study provides novel clues on differential regulation of mTOR under diverse environmental conditions.

Exome sequencing reveals germline gain-of-function EGFR mutation in an adult with Lhermitte-Duclos disease

Lhermitte–Duclos disease (LDD) is a rare cerebellar disorder believed to be pathognomonic for Cowden syndrome. Presently, the only known etiology is germline PTEN mutation. We report a 41-yr-old white female diagnosed with LDD and wild-type for PTEN. Exome sequencing revealed a germline heterozygous EGFR mutation that breaks a disulfide bond in the receptor's extracellular domain, resulting in constitutive activation. Functional studies demonstrate activation of ERK/AKT signaling pathways, mimicking PTEN loss-of-function downstream effects. The identification of EGFR as a candidate LDD susceptibility gene contributes to advancement of molecular diagnosis and targeted therapy for this rare condition with limited treatment options.

Concurrent BRAF and PTEN mutations in melanoma of unknown origin presenting as a breast mass

BACKGROUND

Metastases represent a small percentage of the malignancies affecting the breast, and only 5% of melanomas originate from non-cutaneous sites. Multiple genetic aberrations have been associated with the development of melanocytic lesions, including BRAF V600E mutation. Mutations in PTEN gene have also been related to the pathogenesis of multiple malignancies.

PURPOSE/METHOD

This is the case of a 28-year-old female who presented with a tender, palpable mass in the upper outer quadrant of the right breast. Ultrasound showed a 1-cm solid mass, initially diagnosed as invasive ductal carcinoma on biopsy. During pre-operative workup, a second mass was identified and biopsied. Immunohistochemical stains performed on the second mass biopsy demonstrated that the neoplastic cells were positive for cytokeratin AE1/3, pan-melanoma, tyrosinase, and SOX-10 and negative for CK7, CAM5.2, and GATA-3. Subsequent workup showed widespread metastatic disease involving the liver, lungs, bones, and brain. The brain metastasis tested positive for BRAF p.V600E and PTEN p.R130Efs*4 mutations. Thorough skin and eye examination did not reveal a primary melanoma.

CONCLUSION

Only few reports have been published of melanoma presenting as a breast mass. This is an interesting case due to the clinical presentation, diagnostic challenges, and genetic mutations profile.

Oxymatrine suppresses the growth and invasion of MG63 cells by up-regulating PTEN and promoting its nuclear translocation

Studies demonstrated that reduced PTEN levels are associated with poor prognoses of osteosarcoma. The nuclear localization of PTEN is important for its tumor suppressive function. Equally importantly, PTEN is the most significant negative regulator of PI3K/Akt signaling cascade, the constitutively activated pathway in osteosarcoma. In our study MG63 cells and U2OS cells were treated with the indicated concentrations of oxymatrine, in order to find the inhibition of oxymatrine to cells. We found the functions of oxymatrine on proliferation, apoptosis and invasion in cells. Oxymatrine could increase the expression of PTEN and promote its nuclear translocation in MG63 cells. In addition, oxymatrine could induce cell cycle arrest in G1 phase and apoptosis of MG63 cells. The migration and invasion potential of MG63 cells were also markedly inhibited by oxymatrine. Oxymatrine could suppress the growth and invasion of MG63 human osteosarcoma cells by up-regulating PTEN and promoting its nuclear translocation and inhibiting PI3K/Akt signaling pathway.

LZTS2 and PTEN collaboratively regulate ß-catenin in prostatic tumorigenesis

The leucine zipper tumor suppressor 2 (LZTS2) was identified as a tumor susceptibility gene within the 10q24.3 chromosomal region, and is approximately 15Mb from the PTEN locus. This region containing the both loci is frequently deleted in a variety of human malignancies, including prostate cancer. LZTS2 is a ß-catenin-binding protein and a negative regulator of Wnt signaling. Overexpression of PTEN in prostate cancer cell lines reduces ß-catenin-mediated transcriptional activity. In this study, we examined the collaborative effect of PTEN and LZTS2 using multiple in vitro and in vivo approaches. Co-expression of PTEN and LZTS2 in prostate cancer cells shows stronger repressive effect on ß-catenin mediated transcription. Using a newly generated mouse model, we further assessed the effect of simultaneous deletion of Pten and Lzts2 in the murine prostate. We observed that mice with both Lzts2 and Pten deletion have an earlier onset of prostate carcinomas as well as an accelerated tumor progression compared to mice with Pten or Lzts2 deletion alone. Immunohistochemical analyses show that atypical and tumor cells from compound mice with both Pten and Lzts2 deletion are mainly composed of prostate luminal epithelial cells and possess higher levels of cytoplasmic and nuclear β-catenin. These cells also exhibit a higher proliferative capacity than cells isolated from single deletion mice. These data demonstrate the significance of simultaneous Pten and Lzts2 deletion in oncogenic transformation in prostate cells and implicates a new mechanism for the dysregulation of Wnt/β-catenin signaling in prostate tumorigenesis.

Loss of phosphatase and tensin homolog expression correlates with clinicopathological features of non-small cell lung cancer patients and its impact on survival: A systematic review and meta-analysis

BACKGROUND

Phosphatase and tensin homolog ( PTEN ), regarded as a tumor suppressor gene, may act as a prognostic biomarker in human cancers.

METHODS

All eligible studies from MEDLINE, Embase, CENTRAL, and the Chinese BioMedical Literature Database to October 2016 were incorporated. Two reviewers independently screened the literature according to inclusion and exclusion criteria, extracted the data, assessed the methodological quality of the included studies, and conducted meta-analysis.

RESULTS

A total of 2486 patients from 19 studies were included. PTEN expression was significantly correlated with gender, smoking history, histology (adenocarcinoma [ADC] vs. squamous cell carcinoma), tumor node metastasis stage (I-II vs. III-IV), N status (N0 vs. N1-N3), and distant metastasis (M0 vs. M1). Loss of PTEN expression was associated with poorer overall survival, but had no significant association with disease-free survival. Subgroup analysis showed that negative PTEN expression was associated with a poorer outcome in Asian and ADC patients, but not in Western or squamous cell carcinoma patients.

CONCLUSION

Loss of PTEN might play an unfavorable prognostic role for overall survival of non-small cell lung cancer patients, especially Asian or ADC patients.

Wild-type phosphatase and tensin homolog deleted on chromosome 10 improved the sensitivity of cells to rapamycin through regulating phosphorylation of Akt in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most frequently diagnosed cancers in China, but the etiology and mode of carcinogenesis of this disease remain poorly understood. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN), as a negative regulator of Akt/mTOR pathway, frequently mutates or is inactive in many cancers. Although mTOR has been thought a promising cancer therapeutic target, the sensitivity of tumor cells to rapamycin was still to be revaluated. In this study, we measured the effects of rapamycin on cell proliferation and phosphorylation of Akt in ESCC cells with varying degrees of differentiation. And then, the relationship between PTEN status and the sensitivity of cells to rapamycin was investigated in EC9706 cells with or without wild-type PTEN in vitro and in vivo. The results demonstrated ESCC cells with poor differentiation were insensitive to rapamycin of high concentration and rapamycin obviously promoted the phosphorylation of Akt in these cells, but it had no obvious effects on p-Akt in cells with well differentiation. Also, we showed that wild-type PTEN improved the sensitivity of poor differentiation cells to rapamycin through inhibiting phosphorylation of Akt in vitro and in vivo. This study explored the possible molecular mechanism of some ESCC cells insensitive to rapamycin and provided a measure for treating ESCC patients with PTEN inactivation using mTOR inhibitors.

P110β Inhibition Reduces Histone H3K4 Di-Methylation in Prostate Cancer

INTRODUCTION AND AIMS

Epigenetic alteration plays a major role in the development and progression of human cancers, including prostate cancer. Histones are the key factors in modulating gene accessibility to transcription factors and post-translational modification of the histone N-terminal tail including methylation is associated with either transcriptional activation (H3K4me2) or repression (H3K9me3). Furthermore, phosphoinositide 3-kinase (PI3 K) signaling and the androgen receptor (AR) are the key determinants in prostate cancer development and progression. We recently showed that prostate-targeted nano-micelles loaded with PI3 K/p110beta specific inhibitor TGX221 blocked prostate cancer growth in vitro and in vivo. Our objective of this study was to determine the role of PI3 K signaling in histone methylation in prostate cancer, with emphasis on histone H3K4 methylation.

METHODS

PI3 K non-specific inhibitor LY294002 and p110beta-specific inhibitor TGX221 were used to block PI3 K/p110beta signaling. The global levels of H3K4 and H3K9 methylation in prostate cancer cells and tissue specimens were evaluated by Western blot assay and immunohistochemical staining. A synthetic androgen R1881 was used to stimulate AR activity in prostate cancer cells. A castration-resistant prostate cancer (CRPC) specific human tissue microarray (TMA) was used to assess the global levels of H3K4me2 methylation by immunostaining approach.

RESULTS

Our data revealed that H3K4me2 levels were significantly elevated after androgen stimulation. With RNA silencing and pharmacology approaches, we further defined that inhibition of PI3 K/p110beta activity through gene-specific knocking down and small chemical inhibitor TGX221 abolished androgen-stimulated H3K4me2 methylation. Consistently, prostate cancer-targeted delivery of TGX221 in vivo dramatically reduced the global levels of H3K4me2 as assessed by immunohistochemical staining on tissue section of mouse xenografts from CRPC cell lines 22RV1 and C4-2. Finally, immunostaining data revealed a strong H3K4me2 immunosignal in CRPC tissues compared to primary tumors and benign prostate tissues.

CONCLUSIONS

Taken together, our results suggest that PI3 K/p110beta-dependent signaling is involved in androgen-stimulated H3K4me2 methylation in prostate cancer, which might be used as a novel biomarker for disease prognosis and targeted therapy. Prostate 77:299-308, 2017. © 2016 Wiley Periodicals, Inc.

Apolipoprotein E4, Gender, Body Mass Index, Inflammation, Insulin Resistance, and Air Pollution Interactions: Recipe for Alzheimer's Disease Development in Mexico City Young Females

Given the epidemiological trends of increasing Alzheimer's disease (AD) and growing evidence that exposure and lifestyle factors contribute to AD risk and pathogenesis, attention should be paid to variables such as air pollution, in order to reduce rates of cognitive decline and dementia. Exposure to fine particulate matter (PM2.5) and ozone (O3) above the US EPA standards is associated with AD risk. Mexico City children experienced pre- and postnatal high exposures to PM2.5, O3, combustion-derived iron-rich nanoparticles, metals, polycyclic aromatic hydrocarbons, and endotoxins. Exposures are associated with early brain gene imbalance in oxidative stress, inflammation, innate and adaptive immune responses, along with epigenetic changes, accumulation of misfolded proteins, cognitive deficits, and brain structural and metabolic changes. The Apolipoprotein E (APOE) 4 allele, the most prevalent genetic risk for AD, plays a key role in the response to air pollution in young girls. APOE 4 heterozygous females with >75% to <94% BMI percentiles are at the highest risk of severe cognitive deficits (1.5-2 SD from average IQ). This review focused on the relationships between gender, BMI, systemic and neural inflammation, insulin resistance, hyperleptinemia, dyslipidemia, vascular risk factors, and central nervous system involvement in APOE4 urbanites exposed to PM2.5 and magnetite combustion-derived iron-rich nanoparticles that can reach the brain. APOE4 young female heterozygous carriers constitute a high-risk group for a fatal disease: AD. Multidisciplinary intervention strategies could be critical for prevention or amelioration of cognitive deficits and long-term AD progression in young individuals at high risk.

New Targeted Agents in Gynecologic Cancers: Synthetic Lethality, Homologous Recombination Deficiency, and PARP Inhibitors

OPINION STATEMENT

Inhibitors of poly (ADP-ribose) polymerase (PARP) have emerged as a new class of anti-cancer drugs, specifically for malignancies bearing aberrations of the homologous recombination pathway, like those with mutations in the BRCA 1 and BRCA 2 genes. Olaparib, a potent PARP1 and PARP2 inhibitor, has been shown to significantly increase progression-free survival (PFS) in women with recurrent ovarian cancer related to a germline BRCA mutation and is currently approved fourth-line treatment in these patients. PARP inhibitors (PARPi) target the genetic phenomenon known as synthetic lethality to exploit faulty DNA repair mechanisms. While ovarian cancer is enriched with a population of tumors with known homologous recombination defects, investigations are underway to help identify pathways in other gynecologic cancers that may demonstrate susceptibility to PARPi through synthetically lethal mechanisms. The ARIEL2 trial prospectively determined a predictive assay to identify patients with HRD. The future of cancer therapeutics will likely incorporate these HRD assays to determine the best treatment plan for patients. While the role of PARPi is less clear in non-ovarian gynecologic cancers, the discovery of a predictive assay for HRD may open the door for clinical trials in these other gynecologic cancers enriched with patients with HRD. Identification of patients with tumors deficient in homologous repair or have HRD-like behavior moves cancer treatment towards individualized therapies in order to maximize treatment effect and quality of life for women living with gynecologic cancers.

Heat stress-induced phosphorylation of FoxO3a signalling in rat skeletal muscle

AIM

A recent study demonstrated that FoxO3a was directly induced by the overexpression of Hsp72 in rat soleus muscle. However, whether heat stress treatment induces FoxO3a phosphorylation in rat skeletal muscle remains unclear. This study examined the effects of heat stress on the regulation of the FoxO3a signalling pathway in rat skeletal muscle.

METHODS

Thirty-two male Wistar rats (15 weeks old) were randomly assigned into two groups; sedentary control group (Sed, n = 8) and experimental group (n = 24). After an overnight fast, one leg of each rat (HS leg) in the experimental group was immersed in hot water (43 °C) for 30 min, and the soleus and plantaris muscles in both legs were removed immediately (0 min), 30 min, 60 min, or 24 h after the heat stress (n = 6 each group). The contralateral, non-heated leg in the experimental group served as an internal control (CT leg).

RESULTS

Heat stress treatment resulted in a significant increase in FoxO3a phosphorylation (Ser253) in the soleus and plantaris muscles of heat-stressed legs after 24 h. Hsp72 expression in heat-stressed legs was significantly higher at 60 min and 24 h in these muscles. Activation of the PTEN/Akt and MEK/ERK pathways was also observed in these muscles immediately after stress, but not at 24 h. There were no differences in FoxO1 and AMPKα phosphorylation in either muscle.

CONCLUSION

Heat stress in rat skeletal muscle induces phosphorylation of FoxO3a signalling, and it may be related to Hsp72 upregulation, and the activation of the PTEN/Akt and MEK/ERK pathways.

In Vitro and in Vivo Atheroprotective Effects of Gossypetin against Endothelial Cell Injury by Induction of Autophagy

Oxidized low-density lipoprotein (ox-LDL) contributes to the pathogenesis of atherosclerosis by promoting vascular endothelial cell injury.Gossypetin, a naturally occurring hexahydroxyflavone, has been shown to possess antimutagenic, antioxidant, antimicrobial, and antiatherosclerotic effects. In this study, the atheroprotective role of gossypetin was examined in endothelial cells. The protective effect of gossypetin against ox-LDL-induced injury in human umbilicalvein endothelial cells (HUVECs) was first noted at 0.1−0.5 μM. Gossypetin showed potential in reducing ox-LDL-dependent apoptosis, as demonstrated by morphological and biochemical features, including formation of apoptotic bodies,distribution of hypodiploid phase, and activation of caspase-3. Next, the ox-LDL induced formation of acidic vesicular organelles and the upregulation of autophagyrelated genes (LC3 and Beclin-1) were enhanced by gossypetin. Gossypetin triggered autophagic flux was further confirmed by an increase in the level of LC3-II under pretreatment conditions with an autophagy inhibitor, chloroquine (CQ). In addition, silencing Beclin-1 inhibited both the gossypetin-mediated protective affects and the autophagic process. Molecular data indicated that the autophagic effect of gossypetin might be mediated via the class III PI3K/Beclin-1 and PTEN/class I PI3K/Akt signaling cascades, as demonstrated by the use of a class III PI3K inhibitor, 3-methyladenine (3-MA), and a PTEN inhibitor, SF1670. Finally, gossypetin improved atherosclerotic lesions and endothelial injury in vivo. These data imply that gossypetin upregulates the autophagic pathway, which led to subsequent reduction of ox-LDL-induced atherogenic endothelial cell injury and apoptosis, and provide a new mechanism for the antiatherosclerotic activity of gossypetin.

Small-Molecule Targeting of E3 Ligase Adaptor SPOP in Kidney Cancer

In the cytoplasm of virtually all clear-cell renal cell carcinoma (ccRCC), speckle-type POZ protein (SPOP) is overexpressed and misallocated, which may induce proliferation and promote kidney tumorigenesis. In normal cells, however, SPOP is located in the nucleus and induces apoptosis. Here we show that a structure-based design and subsequent hit optimization yield small molecules that can inhibit the SPOP-substrate protein interaction and can suppress oncogenic SPOP-signaling pathways. These inhibitors kill human ccRCC cells that are dependent on oncogenic cytoplasmic SPOP. Notably, these inhibitors minimally affect the viability of other cells in which SPOP is not accumulated in the cytoplasm. Our findings validate the SPOP-substrate protein interaction as an attractive target specific to ccRCC that may yield novel drug discovery efforts.