Phosphatase and tensin homolog (PTEN) expression on oncologic outcome in renal cell carcinoma: A systematic review and meta-analysis

Expression and prognostic significance of microsomal triglyceride transfer protein in brain tumors: a retrospective cohort study

Background

Glioblastoma (GBM) is the most common malignant brain tumor and has poor survival. An elevated cholesterol level is involved occurrence and progression of brain tumors. Microsomal triglyceride transfer protein (MTTP) is a target for lowering lipids, and its inhibition helps to improve hyperlipidemia. However, whether the altered expression of MTTP affects the development and prognosis of brain tumors is currently unidentified. The purpose of this study is to determine MTTP as a prognostic marker for brain tumors.

Methods

Data for patients with brain cancers and control brain tissue were acquired from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). The datasets were analyzed using Mann-Whitney U-test or t-test to compare the expression of MTTP in normal and brain tumor tissues. To examine whether MTTP affected the prognosis of patients with brain tumors, log-rank test and multivariable Cox proportional hazard regression were conducted.

Results

The expression of MTTP was significantly upregulated in brain tumors and was correlated with age, tumor stage, and isocitrate dehydrogenase (IDH) mutation. Importantly, increased MTTP expression in brain tumors is associated with poor patient survival.

Conclusions

High MTTP expression is associated with brain tumor development, tumor stage, and prognosis. Therefore, MTTP is an independent prognostic indicator for brain tumors, which can serve as one of the possible targets for adjuvant treatment of GBM.

Comparative analysis of the effect of hypoxia in two different tumor cell models shows the differential involvement of PTEN control of proangiogenic pathways

Hypoxia, low, non-physiological oxygen tension is a key regulator of tumor microenvironment, determining the pathological tumor vascularization. Alleviation of hypoxia through vessel normalization may be a promising therapeutic approach. We aimed to assess the role of low oxygen tension in PTEN-related pathways and proangiogenic response, in vitro, in two different tumor cell lines, focusing on potential therapeutic targets for tumor vessel normalization. Downregulation of PTEN in hypoxia mediates the activation of distinct mechanisms: cytoplasmic pAKT activation in melanoma and pMDM2 modulation in kidney cancer. We show that hypoxia-induced proangiogenic potential was stronger in Renca cells than B16 F10-confirmed by a distinct secretory potential and different ability to affect endothelial cells functions. Therefore, the impact of hypoxia on PTEN-mediated regulation may determine the therapeutic targets and effectiveness of vessel normalization and intrinsic characteristics of cancer cell have to be taken into account when designing treatment.

Effect of Silibinin on the Expression of Mir-20b, Bcl2L11, and Erbb2 in Breast Cancer Cell Lines

This study aimed to evaluate the comparative effect of silibinin (SB) on the expression of MiR‑20b and BCL2L11 in T47D and MCF-7 cell lines. Molecular simulation studies were carried out to analyze Erbb2, as a potential target of SB, to direct the breast cancer cells toward apoptosis. At first, cell viability, apoptosis, and cell cycle arrest-inducing capacity of SB were examined using MTT and flow cytometry analysis, respectively. Real-time PCR (RT-PCR) was employed to assess the effect of SB on BCL2L11, Phosphatase and tensin homolog (PTEN), and Caspase 9 mRNarrest-indu. Moreover, alterations in Caspase 9 protein expression were determined using Western blot analysis. Finally, AutoDockVina software was used to dock the SB/ MiR‑20b and SB/ erb-b2 receptor tyrosine kinase 2 (Erbb2) interaction. The obtained data revealed the potent cytotoxicity of SB in both T47D and MCF-7 cells through apoptosis induction and cell cycle arrest. SB-treated cells also showed downregulation of MiR‑20b and high expression of BCL2L11, PTEN, and Caspase 9 mRNA compared to non-treated cancer cells. Computational docking showed a strong interaction between SB/ MiR‑20b and SB/Erbb2. It can be concluded that SB had a strong anti-tumorigenic activity through BCL2L11upregulation and MiR‑20b down expression, maybe through targeting the PTEN and interacting with Erbb2, which resulted in apoptotic induction and cell cycle arrest.

Pten knockout affects drug resistance differently in melanoma and kidney cancer

BACKGROUND

PTEN is a tumor suppressor that is often mutated and nonfunctional in many types of cancer. The high heterogeneity of PTEN function between tumor types makes new Pten knockout models necessary to assess its impact on cancer progression and/or treatment outcomes.

METHODS

We aimed to show the effect of CRISPR/Cas9-mediated Pten knockout on murine melanoma (B16 F10) and kidney cancer (Renca) cells. We evaluated the effect of PTEN deregulation on tumor progression in vivo and in vitro, as well as on the effectiveness of drug treatment in vitro. In addition, we studied the molecular changes induced by Pten knockout.

RESULTS

In both models, Pten mutation did not cause significant changes in cell proliferation in vitro or in vivo. Cells with Pten knockout differed in sensitivity to cisplatin treatment: in B16 F10 cells, the lack of PTEN induced sensitivity and, in Renca cells, resistance to drug treatment. Accumulation of pAKT was observed in both cell lines, but only Renca cells showed upregulation of the p53 level after Pten knockout. PTEN deregulation also varied in the way that it altered PAI-1 secretion in the tested models, showing a decrease in PAI-1 in B16 F10 Pten/KO and an increase in Renca Pten/KO cells. In kidney cancer cells, Pten knockout caused changes in epithelial to mesenchymal transition marker expression, with downregulation of E-cadherin and upregulation of Snail, Mmp9, and Acta2 (α-SMA).

CONCLUSIONS

The results confirmed heterogenous cell responses to PTEN loss, which may lead to a better understanding of the role of PTEN in particular types of tumors and points to PTEN as a therapeutic target for personalized medicine.

Renal Neoplasia Occurring in Patients With PTEN Hamartoma Tumor Syndrome : Clinicopathologic Study of 12 Renal Cell Carcinomas From 9 Patients and Association With Intrarenal "Lipomas"

The aim of this study was to assess the histopathologic spectrum of renal tumors in patients with PTEN hamartoma tumor syndrome (PHTS), with a specific focus on potential features predictive of the underlying syndrome. A multi-institutional study was conducted to obtain clinical and pathologic data on renal tumors arising in patients with PHTS, either diagnosed by germline mutational analysis or clinical criteria for Cowden syndrome. Histologic sections of the renal tumors were re-reviewed for classification. Twelve renal epithelial tumors from 9 patients were identified (4 males and 5 females, with a mean age of 41.8 y), 7 of whom carried germline PTEN mutations. All 12 renal epithelial tumors were renal cell carcinomas (RCCs): 5 were chromophobe RCCs, 4 papillary RCCs, and 3 RCC not otherwise specified. Pathologic stage distribution was: 7 (59%) pT1a, 2 (17%) pT1b, 1 (8%) pT2a, 1 (8%) pT2b, and 1 (8%) pT3a. World Health Organization/International Society of Urological Pathology (WHO/ISUP) histologic grade was applicable in 7 (54%) nonchromophobe tumors: 4 (57%) G2, 2 (29%) G3, and 1 (14%) G4. An unexpected histologic finding was the presence of 2 patients with incidental microscopic collections of intrarenal adipocytes that had no features of angiomyolipoma (and were negative with 2 sensitive PEComa markers: cathepsin-K and GPNMB); both were classified as lipoma/"lipomatous hamartomas." The average follow-up interval was 67.8 months (13 to 172 mo): 5 patients had no evidence of disease, 2 were lost to follow-up, 1 died of other (non-PHTS) causes (ie, prostate cancer), and 1 was alive with metastatic RCC to the lung (RCC not otherwise specified with rhabdoid differentiation). All tumors showed loss of nuclear PTEN staining by immunohistochemistry. Fumarate hydratase was retained and 2SC was negative in all papillary RCCs. CK7 was moderate-strong/diffuse positive in 4 of 5 chromophobe RCCs and in 3 of 4 papillary RCCs. Renal epithelial tumors associated with PHTS represent a heterogeneous group of RCCs, but classic chromophobe and papillary RCC are most common. The majority have a favorable clinical behavior as would be predicted by subtype. In contrast to other hereditary renal neoplasia syndromes, morphologic features of the RCCs do not allow identification of PHTS-associated neoplasia with any degree of specificity in the absence of clinical setting and/or prior history, but the presence of microscopic "lipomas" within the kidney may provide a clue in rare cases. Therefore, clinical suspicion and genetic counseling with germline testing remain necessary for identifying PHTS-associated RCC.

The regulation of PTEN: Novel insights into functions as cancer biomarkers and therapeutic targets

This review summarizes the implications of the primary tumor suppressor protein phosphatase and tensin homolog (PTEN) in aggressive cancer development. PTEN interacts with other cellular proteins or factors suggesting the existence of an intricate molecular network that regulates their oncogenic function. Accumulating evidence has shown that PTEN exists and plays a role in the cytoplasmic organelles and in the nucleus. PTEN blocks phosphoinositide 3-kinases (PI3K)-protein kinase B-mammalian target of rapamycin signaling pathway by dephosphorylating phosphatidylinositol (PI)-3,4,5-triphosphate to PI-4,5-bisphosphate thus counteracting PI3K function. Studies have shown that PTEN expression is tightly regulated at transcriptional, posttranscriptional, and posttranslational levels (including protein-protein interactions and posttranslational modifications). Despite recent advances in PTEN research, the regulation and function of the PTEN gene remain largely unknown. How mutation or loss of specific exons in the PTEN gene occurs and involves in cancer development is not clear. This review illustrates the regulatory mechanisms of PTEN expression and discusses how PTEN participates in tumor development and/or suppression. Future prospects for the clinical applications are also highlighted.

Low gamma-butyrobetaine dioxygenase (BBOX1) expression as a prognostic biomarker in patients with clear cell renal cell carcinoma: a machine learning approach

Gamma-butyrobetaine dioxygenase (BBOX1) is a catalyst for the conversion of gamma-butyrobetaine to l-carnitine, which is detected in normal renal tubules. The purpose of this study was to analyze the prognosis, immune response, and genetic alterations associated with low BBOX1 expression in patients with clear cell renal cell carcinoma (RCC). We analyzed the relative influence of BBOX1 on survival using machine learning and investigated drugs that can inhibit renal cancer cells with low BBOX1 expression. We analyzed clinicopathologic factors, survival rates, immune profiles, and gene sets according to BBOX1 expression in a total of 857 patients with kidney cancer from the Hanyang University Hospital cohort (247 cases) and The Cancer Genome Atlas (610 cases). We employed immunohistochemical staining, gene set enrichment analysis, in silico cytometry, pathway network analyses, in vitro drug screening, and gradient boosting machines. BBOX1 expression in RCC was decreased compared with that in normal tissues. Low BBOX1 expression was associated with poor prognosis, decreased CD8+ T cells, and increased neutrophils. In gene set enrichment analyses, low BBOX1 expression was related to gene sets with oncogenic activity and a weak immune response. In pathway network analysis, BBOX1 was linked to regulation of various T cells and programmed death-ligand 1. In vitro drug screening showed that midostaurin, BAY-61-3606, GSK690693, and linifanib inhibited the growth of RCC cells with low BBOX1 expression. Low BBOX1 expression in patients with RCC is related to short survival time and reduced CD8+ T cells; midostaurin, among other drugs, may have enhanced therapeutic effects in this context.

Case Report: Pancreatic metastasis of renal cell carcinoma 16 years after nephrectomy

Background

Renal cell carcinoma (RCC) is the most common renal malignancy, and may metastasize to different sites in the body via hematogenous and lymphomatous routes. The pancreas is a rare metastatic site of metastatic RCC (mRCC) and isolated pancreatic metastasis of RCC (isPMRCC) is even rarer.

Results

The present report describes a case of isPMRCC that recurred 16 years after surgery. The patient responded well to the treatment with pancreaticoduodenectomy and systemic therapy, and no recurrence was recorded after 2 years.

Conclusions

isPMRCC is a distinct subgroup of RCC with unique clinical characteristics that may be explained by its underlying molecular mechanisms. Surgery and systemic therapy confer survival benefits to patients with isPMRCCs, although the recurrence problem has to be paid attention to.

Molecular mechanisms of resistance to tyrosine kinase inhibitor in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell carcinoma (RCC). Loss of von Hippel-Lindau tumor suppressor gene is frequently observed in ccRCC and increases the expression of hypoxia-inducible factors and their targets, including epidermal growth factor, vascular endothelial growth factor, and platelet-derived growth factor. Tyrosine kinase inhibitors (TKIs) offer a survival benefit in metastatic renal cell carcinoma (mRCC). Recently, immune checkpoint inhibitors have been introduced in mRCC. Combination therapy with TKIs and immune checkpoint inhibitors significantly improved patient outcomes. Therefore, TKIs still play an essential role in mRCC treatment. However, the clinical utility of TKIs is compromised when primary and acquired resistance are encountered. The mechanism of resistance to TKI is not fully elucidated. Here, we comprehensively reviewed the molecular mechanisms of resistance to TKIs and a potential strategy to overcome this resistance. We outlined the involvement of angiogenesis, non-angiogenesis, epithelial-mesenchymal transition, activating bypass pathways, lysosomal sequestration, non-coding RNAs, epigenetic modifications and tumor microenvironment factors in the resistance to TKIs. Deep insight into the molecular mechanisms of resistance to TKIs will help to better understand the biology of RCC and can ultimately help in the development of more effective therapies.

Research Progress of PI3K/PTEN/AKT Signaling Pathway Associated with Renal Cell Carcinoma

Renal cell carcinoma is a common renal malignancy of the urinary system and the most malignant type of kidney cancer. Phosphatidylinositol 3-kinase (PI3K) is an intracellular phosphatidylinositol kinase associated with oncogene products such as v-src and with serine/threonine kinase activity, and its increased activity correlates with the development of several cancers. Protein kinase B (AKT) is a cyclic guanosine phosphate-dependent protein kinase that plays an important role in cell survival and apoptosis. Phosphatase and tensin homolog (PTEN), a newly discovered oncogene in recent years, participates in tumorigenesis and development by competing with tyrosine kinases for common substrates. The product encoded by PTEN was found to negatively regulate the PI3K/Akt signaling pathway, thereby inhibiting cell proliferation and promoting apoptosis. The PI3K/PTEN/AKT signaling pathway has also been identified in several studies as being involved in the development of several malignancies, including renal cell carcinoma. Radiotherapy is currently one of the most effective means of treatment for renal cell carcinoma, whereas it is predisposed to significant tolerance during the course of radiotherapy, thereby leading to treatment failure. Therefore, new treatment options may potentiate the efficiency of renal cell carcinoma treatment. With the development of tumor molecular biology, targeted biological therapy for malignant tumors has gradually become a research hotspot. Given the above research background, this study reviews the application of the PI3K/PTEN/AKT signaling pathway in renal cell carcinoma, aiming to provide more references for the treatment of clinical renal cell carcinoma.

miRNA Pattern in Hypoxic Microenvironment of Kidney Cancer—Role of PTEN

MicroRNAs are post-transcriptional regulators of gene expression, and disturbances of their expression are the basis of many pathological states, including cancers. The miRNA pattern in the context of tumor microenvironment explains mechanisms related to cancer progression and provides a potential target of modern therapies. Here we show the miRNA pattern in renal cancer focusing on hypoxia as a characteristic feature of the tumor microenvironment and dysregulation of PTEN, being a major tumor suppressor. Methods comprised the CRSPR/Cas9 mediated PTEN knockout in the Renca kidney cancer cell line and global miRNA expression analysis in both in vivo and in vitro (in normoxic and hypoxic conditions). The results were validated on human cancer models with distinct PTEN status. The increase in miR-210-3p in hypoxia was universal; however, the hypoxia-induced decrease in PTEN was associated with an increase in miR-221-3p, the loss of PTEN affected the response to hypoxia differently by decreasing miR-10b-5p and increasing miR-206-3p. In turn, the complete loss of PTEN induces miR-155-5p, miR-100-5p. Upregulation of miR-342-3p in knockout PTEN occurred in the context of the whole tumor microenvironment. Thus, effective identification of miRNA patterns in cancers must consider the specificity of the tumor microenvironment together with the mutations of key suppressors.

Brusatol inhibits the growth of renal cell carcinoma by regulating the PTEN/PI3K/AKT pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Brucea javanica (L.) Merr. is a medicinal herb used in China for the prevention and treatment of diseases such as cancer and malaria. Brusatol was isolated from the seeds of Brucea javanica (L.) Merr, brusatol has a wide range of pharmacological effects, including anti-inflammation and anti-cancer effects.

AIM OF THE STUDY

Renal cell carcinoma is one of the most common urinary system tumours and seriously threatens the lives of patients. We aimed to study the mechanism by which brusatol regulates the growth of renal cancer cells through the PTEN/PI3K/AKT signalling pathway.

MATERIALS AND METHODS

We chose the A498, ACHN, and OSRC-2 cell lines as experimental models. After intervention with brusatol, CCK-8 experiments and plate cloning experiments were used to detect the cell proliferation ability; flow cytometry was used to detect the cell apoptosis rate; scratch and transwell invasion assays were used to detect the cell migration and invasion ability; qRT-PCR and Western blotting was used to detect PTEN, p-PI3K/PI3K, p-AKT/AKT, Bax, Bcl2, E-cadherin, N-cadherin, and vimentin relative expression. Then, we knocked down the PTEN gene in the three cell lines and again tested the proliferation, apoptosis, migration, and invasion capabilities of each group of cells.

RESULTS

Brusatol significantly inhibited the proliferation, migration and invasion and increased the rate of apoptosis of the A498, ACHN, and OSRC-2 cell lines, and brusatol significantly increased the expression of PTEN mRNA and protein, and inhibited the expression of p-PI3K and p-AKT. Moreover, knockdown of PTEN significantly reduced the inhibitory effect of brusatol on the growth of renal cancer cells.

CONCLUSION

Our research results show that brusatol has an effective inhibitory effect on the growth of A498, ACHN, and OSRC-2 renal cancer cell lines, and this effect is likely to be produced by regulating the PTEN/PI3K/AKT signalling pathway.

Biomarker-Based Phase II Study of Sapanisertib (TAK-228): An mTORC1/2 Inhibitor in Patients With Refractory Metastatic Renal Cell Carcinoma

PURPOSE

Sapanisertib is a kinase inhibitor that inhibits both mammalian target of rapamycin complex 1 (mTORC1) and mTORC2. In this multicenter, single-arm phase II trial, we evaluated the efficacy of sapanisertib in patients with treatment-refractory metastatic renal cell carcinoma (mRCC; NCT03097328).

METHODS

Patients with mRCC of any histology progressing through standard therapy (including prior mTOR inhibitors) had baseline biopsy and received sapanisertib 30 mg by mouth once weekly until unacceptable toxicity or disease progression. The primary end point was objective response rate by RECIST 1.1. Tissue biomarkers of mTOR pathway activation were explored.

RESULTS

We enrolled 38 patients with mRCC (clear cell = 28; variant histology = 10) between August 2017 and November 2019. Twenty-four (63%) had received ≥ 3 prior lines of therapy; 17 (45%) had received prior rapalog therapy. The median follow-up was 10.4 (range 1-27.4) months. Objective response rate was two of 38 (5.3%; 90% CI, 1 to 15.6); the median progression-free survival (PFS) was 2.5 months (95% CI, 1.8 to 3.7). Twelve patients (32%) developed treatment-related grade 3 adverse events, with no grade 4 or 5 toxicities. Alterations in the mTOR pathway genes were seen in 5 of 29 evaluable patients (MTOR n = 1, PTEN n = 3, and TSC1 n = 1) with no association with response or PFS. Diminished or loss of PTEN expression by immunohistochemistry was seen in 8 of 21 patients and trended toward shorter PFS compared with intact PTEN (median 1.9 v 3.7 months; hazard ratio 2.5; 95% CI, 0.9 to 6.7; P = .055).

CONCLUSION

Sapanisertib had minimal activity in treatment-refractory mRCC independent of mTOR pathway alterations. Additional therapeutic strategies are needed for patients with refractory mRCC.

PTEN as a Therapeutic Target in Pulmonary Hypertension Secondary to Left-heart Failure: Effect of HO-3867 and Supplemental Oxygenation

Pulmonary hypertension (PH) is a condition when the pressure in the lung blood vessels is elevated. This leads to increase in thickness of the blood vessels and increases the workload of the heart and lungs. The incidence and prevalence of PH has been on the increase in the last decade. It is estimated that PH affects about 1% of the global population and about 10% of individuals >65 years of age. Of the various types, Group 2 PH is the most common type seen in the elderly population. Fixed PH or PH refractive to therapies is considered a contraindication for heart transplantation; the 30-day mortality in heart transplant recipients is significantly increased in the subset of this population. In general, the pathobiology of PH involves multiple factors including hypoxia, oxidative stress, growth factor receptors, vascular stress, etc. Hence, it is challenging and important to identify specific mechanisms, diagnosis and develop effective therapeutic strategies. The focus of this manuscript is to review some of the important pathobiological processes and mechanisms in the development of PH. Results from our previously reported studies, including targeted treatments along with some new data on PH secondary to left-heart failure, are presented.

Orbital Tumor As First Manifestation of Metastatic Renal Cell Carcinoma

Orbital metastasis from renal cell carcinoma (RCC) is uncommon. Orbital tumor, as the first presentation of RCC, is rare as the majority of orbital metastases occur after a confirmed diagnosis of primary cancer. We report a case of the metastatic orbital tumor as the first manifestation of RCC, which presented with painless left eye proptosis for two months' duration, associated with blurring of vision and diplopia. Otherwise, the systemic review was unremarkable. Examination showed left eye non-axial proptosis with a pulsatile, multilobulated mass over the left supraorbital area extending to the left frontal region, limited ocular motility, and impaired optic nerve functions. CT of the orbit showed a mass arising from the left frontal and greater wing of the left sphenoid bone, with infiltration to the left lateral rectus, left superior oblique, and lacrimal gland. Further systemic investigation with CT thorax, abdomen, and pelvis revealed left RCC with para-aortic nodes, lungs, and bone metastases. The patient was planned for palliative care.

Clear Cell Renal Carcinoma: MicroRNAs With Efficacy in Preclinical In Vivo Models

In order to identify new targets and treatment modalities for clear cell renal carcinoma, we surveyed the literature with respect to microRNAs involved in this disease. In this review, we have focused on up- and down-regulated miRs which mediate efficacy in preclinical clear-cell renal carcinoma-related in vivo models. We have identified 10 up-regulated and 33 down-regulated micro-RNAs according to this criterion. As proof-of-concept, micro-RNAs interfering with VEGF (miR-205p) and mTOR (mir-99a) pathways, which are modulated by approved drugs for this disease, have been identified. miRs targeting hypoxia induced factor-2α (HIF-2α) (miR-145), E3 ubiquitinylases speckle-type POZ protein (SPOP) (miR 520/372/373) and casitas B-lineage lymphoma (CBL) (miR-200a-3p), interfere with druggable targets. Further identified miRs interfere with cell-cycle dependent kinases, such as CDK2 (miR-200c), CDK4, 6 (miR-1) and CDK4, 9 (206c). Transmembrane receptor Ral interacting protein of 76 kD (RLIP76), targeted by mir-137, has emerged as another important target for ccRCC. Additional miRs and their targets merrying further preclinical validation are discussed.

Exploration of immune-related genes in high and low tumor mutation burden groups of chromophobe renal cell carcinoma

Renal cell carcinoma (RCC) is one of most common cancers with gradually increasing incidence and high mortality. Chromogenic RCC (chRCC) is the third most common histological subtype of RCC, accounting for approximately 5–7% of RCC. In our study, the transcriptome expression profile data (n=89) of chRCC, corresponding clinical data (n=113) and the somatic mutation data (n=66) were obtained from the TCGA database. We first analyzed the mutation data of chRCC patients and divided chRCC patients into high and low tumor mutation burden (TMB) groups based on the median TMB. We found that high TMB was significantly associated with worse prognosis and could promote tumor metastasis and development. Moreover, four different immune-related genes (BIRC5, PDGFRL, INHBE, IL20RB) were also identified. We found that BIRC5 was significantly overexpressed in the high TMB group and correlated with worse prognosis. The results of univariate and multivariate COX analyses demonstrated that BIRC5 (hazard ratio (HR) = 2.094) may serve as a prognostic indicator for patients with chRCC with high TMB. In addition, we identified the possible functional pathways of BIRC5 through gene set enrichment analysis (GSEA) enrichment. A positive correlation was obtained between BIRC5 and the abundance of CD4⁺ T cells. The results of our study revealed their correlation between the immune-related genes and clinicopathologic features as well as potential functional pathways as well as immune infiltrating cells, which may provide more data about the development of chRCC immunotherapy.

Prognostic significance of PI3K/AKT/ mTOR signaling pathway members in clear cell renal cell carcinoma

Background

Renal cell carcinoma (RCC) is a fatal disease, in which the PI3K/AKT/mTOR signaling pathway serves an important role in the tumorigenesis. Previous studies have reported the prognostic significance of PI3K/AKT/mTOR signaling pathway members in RCC; however, there is insufficient evidence to date to confirm this. Thus, the present study aimed to systematically investigate the prognostic roles of multiple PI3K/AKT/mTOR signaling proteins in clear cell RCC (ccRCC) using online large-scale databases.

Methods

The mRNA expression profiles of PI3K/AKT/mTOR signaling pathway proteins PTEN, PIK3CA, PIK3CB, PIK3CD, PIK3CG, AKT1, AKT2, AKT3 and mTOR were investigated using the Gene Expression Profiling Interactive Analysis (GEPIA) and Oncomine databases, and the protein expression levels of PI3K, AKT and mTOR were detected using western blotting (WB) analysis. In addition, the correlation between mRNA or protein expression levels and the prognostic significance was analyzed using the Kaplan-Meier (K-M) plotter (n = 530), the Human Protein Atlas (HPA; n = 528) and The Cancer Protein Atlas (TCPA; n = 445) databases.

Results

The GEPIA revealed that the mRNA expression of major PI3K/AKT/mTOR pathway members, including PTEN, PIK3CA, PIK3CB, AKT1, AKT2 and AKT3, were negatively correlated with ccRCC stages (P < 0.05), though most of their mRNA and protein expression levels were notsignificantly different between ccRCC and normal tissues using GEPIA, Oncomine and WB analyses (P < 0.05). Meanwhile, using the K-M plotter and HPA prognostic analysis, it was found that the mRNA expression levels of the majority of the PI3K/AKT/mTOR signaling pathway members, including PTEN, PIK3CA, PIK3CB, PIK3CG, AKT3 and mTOR were positively correlated with overall survival (OS), whereas PIK3CD mRNA expression was negatively correlated with OS (P < 0.05). Furthermore, TCPA prognostic analysis observed that several of the key molecules of the PI3K/AKT/mTOR signaling pathway [PTEN, p-AKT (S473) and p-mTOR (S2448)] were also positively correlated with OS in patients with ccRCC (P < 0.05). In conclusion, the present study suggested that several members of the PI3K/AKT/mTOR signaling pathway, especially PTEN, may be favorable prognostic factors in ccRCC, which indicated that the PI3K/AKT/mTOR signaling pathway may be implicated in ccRCC initiation and progression.

Significance of PI3K signalling pathway in clear cell renal cell carcinoma in relation to VHL and HIF status

Renal cell carcinoma (RCC) includes diverse tumour types characterised by various genetic abnormalities. The genetic changes, like mutations, deletions and epigenetic alterations, play a crucial role in the modification of signalling networks, tumour pathogenesis and prognosis. The most prevalent RCC type, clear cell RCC (ccRCC), is asymptomatic in the early stages and has a poorer prognosis compared with the papillary and the chromophobe types RCCs. Generally, ccRCC is refractory to chemotherapy and radiation therapy. Loss of von Hippel-Lindau (VHL) gene and upregulation of hypoxia-inducible factors (HIF), the signature of most sporadic ccRCC, promote multiple growth factors. Hence, VHL/HIF and a variety of pathways, including phosphatase and TEnsin homolog on chromosome 10/phosphatidylinositol-3-kinase (PI3K)/AKT, are closely connected and contribute to the ontogeny of ccRCC. In the recent decade, multiple targeting agents have been developed based on blocking major signalling pathways directly or indirectly involved in ccRCC tumour progression, metastasis, angiogenesis and survival. However, most of these drugs have limitations; either metastatic ccRCC develops resistance to these agents, or despite blocking receptors, tumour cells use alternate signalling pathways. This review compiles the state of knowledge about the PI3K/AKT signalling pathway confined to ccRCC and its cross-talks with VHL/HIF pathway.

Precise Immunodetection of PTEN Protein in Human Neoplasia

PTEN is a major tumor-suppressor protein whose expression and biological activity are frequently diminished in sporadic or inherited cancers. PTEN gene deletion or loss-of-function mutations favor tumor cell growth and are commonly found in clinical practice. In addition, diminished PTEN protein expression is also frequently observed in tumor samples from cancer patients in the absence of PTEN gene alterations. This makes PTEN protein levels a potential biomarker parameter in clinical oncology, which can guide therapeutic decisions. The specific detection of PTEN protein can be achieved by using highly defined anti-PTEN monoclonal antibodies (mAbs), characterized with precision in terms of sensitivity for the detection technique, specificity for PTEN binding, and constraints of epitope recognition. This is especially relevant taking into consideration that PTEN is highly targeted by mutations and posttranslational modifications, and different PTEN protein isoforms exist. The precise characterization of anti-PTEN mAb reactivity is an important step in the validation of these reagents as diagnostic and prognostic tools in clinical oncology, including their routine use in analytical immunohistochemistry (IHC). Here, we review the current status on the use of well-defined anti-PTEN mAbs for PTEN immunodetection in the clinical context and discuss their potential usefulness and limitations for a more precise cancer diagnosis and patient benefit.

miR-130b Promotes Sunitinib Resistance through Regulation of PTEN in Renal Cell Carcinoma

BACKGROUND

MicroRNAs are a class of small noncoding RNAs that play an important role in progression and drug resistance in cancer. Several reports have shown that miR-130b modulates cell growth and drug resistance in some cancers. However, the expression and biological role of miR-130b in renal cell carcinoma (RCC) remain poorly understood. This study aimed to examine the expression and functional role of miR-130b and to analyze the association between miR-130b and sunitinib resistance in RCC.

METHODS

The expression of miR-130b in 32 RCC tissues and their corresponding normal kidney tissues was determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR). We performed a 4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT) assay in RCC cell lines transfected with miR-130b inhibitor or miR-130b mimics. We evaluated the relationship between miR-130b and PTEN and also analyzed the effect of miR-130b on sunitinib resistance.

RESULTS

qRT-PCR analysis showed that the expression of miR-130b was higher in RCC tissues than in corresponding normal kidney tissues. The MTT assay revealed that miR-130b modulated cell growth. qRT-PCR revealed an inverse correlation between miR-130b and PTEN in RCC. Western blotting demonstrated that miR-130b regulated the expression of PTEN in the RCC cell line. Additionally, miR-130b was associated with sunitinib resistance through regulation of PTEN. We established the sunitinib-resistant Caki-1 (Caki-1-SR) cells and observed that the expression of miR-130b was elevated in Caki-1-SR cells compared with parental Caki-1 cells. Knockdown of miR-130b improved sunitinib resistance in Caki-1-SR cells.

CONCLUSION

The expression of miR-130b was upregulated in RCC. miR-130b promoted cell growth and was associated with sunitinib resistance through regulating PTEN expression. Collectively, these results suggest that miR-130b may play an oncogenic role and be a promising therapeutic target.

Significance of PTEN Mutation in Cellular Process, Prognosis, and Drug Selection in Clear Cell Renal Cell Carcinoma

It is well established that the PTEN (Phosphatase and Tensin Homolog) mutant is a frequently mutated gene found in clear cell renal cell carcinoma (ccRCC), making it a potential biomarker for individualized treatment opinions. Here, in the present study, we designed a method to evaluate the significance of the PTEN mutation in the prognosis and drug selection of ccRCC, determine the potential changing pathways and genes associated with the mechanisms. The most recent TCGA data shows that the PTEN mutation is found in 5% of ccRCC patients. In total, 2,569 genes were identified as DEGs. GO and KEGG analysis suggested that DEGs were significantly enriched in categories associated with cell division and multiple metabolic progressions. The top 10 genes, ranked by degree, were identified as hub genes from the protein–protein interaction network (PPI). What is more, patients with the PTEN mutation were associated with a worsened prognosis of ccRCC. Data from the GDSC database indicated that the selective AKT inhibitor, GSK690693, is a selective inhibitor for ccRCC with the PTEN mutation. Our findings have indicated that multiple genes and pathways may play a crucial role in PTEN mutation ccRCC, offering candidate targets and strategies for PTEN mutation ccRCC individualized treatment.

PTEN as a Prognostic/Predictive Biomarker in Cancer: An Unfulfilled Promise?

Identifying putative biomarkers of clinical outcomes in cancer is crucial for successful enrichment, and for the selection of patients who are the most likely to benefit from a specific therapeutic approach. Indeed, current research in personalized cancer therapy focuses on the possibility of identifying biomarkers that predict prognosis, sensitivity or resistance to therapies. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor gene that regulates several crucial cell functions such as proliferation, survival, genomic stability and cell motility through both enzymatic and non-enzymatic activities and phosphatidylinositol 3-kinase (PI3K)-dependent and -independent mechanisms. Despite its undisputed role as a tumor suppressor, assessment of PTEN status in sporadic human tumors has yet to provide clinically robust prognostic, predictive or therapeutic information. This is possibly due to the exceptionally complex regulation of PTEN function, which involves genetic, transcriptional, post-transcriptional and post-translational events. This review shows a brief summary of the regulation and function of PTEN and discusses its controversial aspects as a prognostic/predictive biomarker.

PTEN Expression, Not Mutation Status in TSC1, TSC2, or mTOR, Correlates with the Outcome on Everolimus in Patients with Renal Cell Carcinoma Treated on the Randomized RECORD-3 Trial

PURPOSE

Genomic alterations in key components of PI3K/mTOR pathway have been proposed as candidate predictive markers for rapalog therapy in renal cell carcinoma (RCC). We tested this hypothesis in patients from a randomized phase II trial of everolimus versus sunitinib.

PATIENTS AND METHODS

Archival specimens collected at baseline were analyzed with targeted next-generation sequencing (NGS). Focus of interest were alterations in key PI3K pathway components. PTEN expression was assessed by IHC. Association between molecular findings and treatment outcomes was investigated; same associations were tested for 2 everolimus-treated trial cohorts in gastric and hepatocellular carcinoma (HCC).

RESULTS

Among 184 everolimus-treated patients with RCC with NGS data, mutation rates in genes of interest were 6% (TSC1), 4.4% (TSC2), and 8.2% (mTOR); 44% harbored alterations in ≥1 PI3K pathway component. For subjects with presence versus absence of mutations in TSC1, TSC2, or mTOR progression-free survival (PFS) neither differed on univariate analysis (HR, 1.0; P = 0.895) nor on multivariate testing stratified by MSKCC risk group and other established prognostic factors (HR, 1.1; P = 0.806). Everolimus-treated patients with retained (n = 50) versus lost (n = 50) PTEN IHC expression had median PFS of 5.3 months versus 10.5 months (HR, 2.5; P < 0.001). Such differences were not seen with sunitinib (10.9 months vs. 10.3 months; HR, 0.8; P = 0.475). Molecular findings did not correlate with outcomes in gastric and HCC cohorts.

CONCLUSIONS

Association between mutation status for TSC1/TSC2/mTOR and therapeutic outcome on everolimus was not confirmed. Clinically meaningful differences in PFS were seen based on PTEN expression by IHC, lost in >50% of patients.

MiR-19a negatively regulated the expression of PTEN and promoted the growth of ovarian cancer cells

Ovarian cancer is the most lethal malignancy of the women genital tract. Exploring novel factors involved in the development of ovarian cancer and characterizing the molecular mechanisms by which regulate the tumorigenesis of ovarian cancer are quite necessary. Here, we found that miR-19a was highly expressed in ovarian cancer tissues and cell lines. Overexpression of miR-19a promoted the viability of ovarian cancer cells, while down-regulation of miR-19a inhibited the growth of ovarian cancer cells. To further understand the underlying molecular mechanism of miR-19a in regulating ovarian cancer cell growth, the downstream targets of miR-19a were predicted. The bioinformatics analysis showed that the tumor suppressor PTEN was found as one of the targeting candidates of miR-19a. MiR-19a bound the 3'-UTR of PTEN and highly expressed miR-19a decreased both the mRNA and protein levels of PTEN in ovarian cancer cells. Overexpression of PTEN suppressed the promoting effect of miR-19a on regulating the growth of ovarian cancer cells. Notably, the expression of miR-19a and PTEN was inversely correlated in ovarian cancer tissues. These results demonstrated the potential oncogenic role of miR-19a in ovarian cancer, which suggested that miR-19a might be a promising target in the diagnosis and treatment of ovarian cancer.