PI3K-Akt-mTOR inhibition by GNE-477 inhibits renal cell carcinoma cell growth in vitro and in vivo

Therapeutic impacts of GNE‑477‑loaded H2O2 stimulus‑responsive dodecanoic acid‑phenylborate ester‑dextran polymeric micelles on osteosarcoma

Osteosarcoma (OS) is a highly malignant primary bone neoplasm that is the leading cause of cancer‑associated death in young people. GNE‑477 belongs to the second generation of mTOR inhibitors and possesses promising potential in the treatment of OS but dose tolerance and drug toxicity limit its development and utilization. The present study aimed to prepare a novel H2O2 stimulus‑responsive dodecanoic acid (DA)‑phenylborate ester‑dextran (DA‑B‑DEX) polymeric micelle delivery system for GNE‑477 and evaluate its efficacy. The polymer micelles were characterized by morphology, size and critical micelle concentration. The GNE‑477 loaded DA‑B‑DEX (GNE‑477@DBD) tumor‑targeting drug delivery system was established and the release of GNE‑477 was measured. The cellular uptake of GNE‑477@DBD by three OS cell lines (MG‑63, U2OS and 143B cells) was analyzed utilizing a fluorescent tracer technique. The hydroxylated DA‑B was successfully grafted onto dextran at a grafting rate of 3%, suitable for forming amphiphilic micelles. Following exposure to H2O2, the DA‑B‑DEX micelles ruptured and released the drug rapidly, leading to increased uptake of GNE‑477@DBD by cells with sustained release of GNE‑477. The in vitro experiments, including MTT assay, flow cytometry, western blotting and RT‑qPCR, demonstrated that GNE‑477@DBD inhibited tumor cell viability, arrested cell cycle in G1 phase, induced apoptosis and blocked the PI3K/Akt/mTOR cascade response. In vivo, through the observation of mice tumor growth and the results of H&E staining, the GNE‑477@DBD group exhibited more positive therapeutic outcomes than the free drug group with almost no adverse effects on other organs. In conclusion, H2O2‑responsive DA‑B‑DEX presents a promising delivery system for hydrophobic anti‑tumor drugs for OS therapy.

Identification of novel mycocompounds as inhibitors of PI3K/AKT/mTOR pathway against RCC

PI3K/AKT/mTOR pathway is one of the frequently disrupted signaling pathways in renal cell carcinoma (RCC) that plays a significant role in tumor formation, disease progression and therapeutic resistance. Therefore, novel natural molecules targeting the critical proteins of this pathway will provide the best alternative to existing drugs, which are toxic and develops resistance. Recent studies have recognized the anti-cancer therapeutic potential of mycocompounds. The current study is focused on screening various mycocompounds from Astraeus hygrometricus against key cancer signaling proteins phosphoinositide 3-kinase (PI3K), protein kinase B, PKB (AKT1) and mammalian target of rapamycin (mTOR). We also studied in-silico cancer cells cytotoxicity and ADMET (absorption, distribution, metabolism, excretion and toxicity) profiles to elucidate the molecular mechanism against RCC and also to uncover the pharmacokinetic profile of these compounds. Astrakurkurone and Ergosta-4,6, 8-(14) 22-tetraene-3-one were the two most efficacious compounds with highest interaction scores and bonding. These compounds were both active against RCC4 and VMRC-RCZ cell lines of RCC. The ADME profiles of both were satisfactory based on druglikeness and bioavailability score criteria. Thus, this proposed study identified astrakurkurone and ergosta-4,6, 8-(14) 22-tetraene-3-one as potential anticancer drug candidates, and provides comparative structural insight into their binding to the 3 protein kinases.

Troxerutin alleviates kidney injury in rats via PI3K/AKT pathway by enhancing MAP4 expression

Background

Troxerutin is a flavonoid compound and possesses potential anti-cancer, antioxidant, and anti-inflammatory activities. Besides, cisplatin is one of the most widely used therapeutic agents, but the clinical uses of cisplatin are often associated with multiple side effects, among which nephrotoxicity is more common.

Objective and design

This study explored the protective effects of troxerutin (150 mg kg⁻¹ day⁻¹ for 14 days) against cisplatin-induced kidney injury and the potential mechanism using Wistar rats as an experimental mammalian model.

Results

We discovered that troxerutin could significantly alleviate cisplatin-induced renal dysfunction, such as increased levels of blood urea nitrogen and creatinine (P < 0.01), as well as improved abnormal renal tissue microstructure and ultrastructure. Additionally, troxerutin significantly decreased malondialdehyde (MDA), hydrogen peroxide (H₂O₂), NO, inducible nitric oxide synthase (iNOS) levels (P < 0.01), p-NF-κB p65/NF-κB p65, TNF-α, Pro-IL-1β, IL-6, B cell lymphoma-2 (Bcl-2)/Bcl-xl associated death promoter (Bad), Cytochrome C (Cyt C), Cleaved-caspase 9, Cleaved-caspase 3, and Cleaved-caspase 8 protein levels (P < 0.01) in the kidney tissues of cisplatin-treated rats; and increased superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), total antioxidant capacity (T-AOC) activities (P < 0.01), IL-10, Bcl-2 protein levels (P < 0.01).

Conclusion

These results suggested that the underlying mechanism might be attributed to the regulation of Phosphoinositide 3 kinase/Protein kinase B (PI3K/AKT) pathway via enhancing MAP4 expression to attenuate cellular apoptosis, alleviating oxidative stress and inflammatory response.

Recent Advances in Dual PI3K/mTOR Inhibitors for Tumour Treatment

The PI3K-Akt-mTOR pathway is a viable target for cancer treatment and can be used to treat various malignant tumours, including follicular lymphoma and breast cancer. Both enzymes, PI3K and mTOR, are critical in this pathway. Hence, in recent years, an array of inhibitors targeting these two targets have been studied, showing dual PI3K/mTOR inhibition compared with single targeting small molecule inhibitors. Inhibitors not only inhibit cell proliferation but also promote cell apoptosis. These inhibitors show high potency and little drug resistance even at low doses, suggesting that PI3K/mTOR inhibitors are promising cancer drugs. Herein, we summarised the recent research of PI3K/mTOR dual inhibitors—for example, structure-activity relationship, pharmacokinetics, and clinical practice, and briefly commented on them.

Clinical Trial Registration:https://clinicaltrials.gov.

Unique characteristics of tertiary lymphoid structures in kidney clear cell carcinoma: prognostic outcome and comparison with bladder cancer

BACKGROUND

The aims of this study were (1) to clarify the impact of tertiary lymphoid structure (TLS) status on the outcome and immunogenomic profile of human clear cell renal cell carcinoma (ccRCC) and (2) to determine phenotypic differences in TLSs between different types of genitourinary cancer, that is, urinary ccRCC and bladder cancer.

METHODS

We performed a quantitative immunohistological analysis of ccRCC tissue microarrays and conducted integrated genome mutation analysis by next-generation sequencing and methylation array analysis. Since the tumor immune microenvironment of ccRCC often differs from that of other cancer types, we analyzed the phenotypic differences in TLSs between ccRCC and in-house bladder cancer specimens.

RESULTS

Varying distribution patterns of TLSs were observed throughout ccRCC tumors, revealing that the presence of TLSs was related to poor prognosis. An analysis of genomic alterations based on TLS status in ccRCC revealed that alterations in the PI3K-mTOR pathway were highly prevalent in TLS-positive tumors. DNA methylation profiling also revealed distinct differences in methylation signatures among ccRCC samples with different TLS statuses. However, the TLS characteristics of ccRCC and bladder cancer markedly differed: TLSs had the exact opposite prognostic impact on bladder cancer as on ccRCC. The maturity and spatial distribution of TLSs were significantly different between the two cancer types; TLSs were more mature with follicle-like germinal center organization and likely to be observed inside the tumor in bladder cancer. Labeling for CD8, FOXP3, PD-1, and PD-L1 showed marked differences in the diversity of the immune microenvironment surrounding TLSs. The proportions of CD8-, FOXP3-, and PD-L1-positive cells were significantly higher in TLSs in bladder cancer than in TLSs in ccRCC; rather the proportion of PD-1-positive cells was significantly higher in TLSs in ccRCC than in TLSs in bladder cancer.

CONCLUSION

The immunobiology of ccRCC is unique, and various cancerous phenomena conflict with that seen in other cancer types; therefore, comparing the TLS characteristics between ccRCC and bladder cancer may help reveal differences in the prognostic impact, maturity and spatial distribution of TLSs and in the immune environment surrounding TLSs between the two cancers.

The New PI3K/mTOR Inhibitor GNE-477 Inhibits the Malignant Behavior of Human Glioblastoma Cells

The most common primary central nervous system tumor in adults is glioblastoma multiforme (GBM). The high invasiveness of GBM cells is an important factor leading to inevitable tumor recurrence and a poor prognosis of patients. GNE-477, a novel PI3K/mTOR inhibitor, has been reported to exert antiproliferative effects on other cancer cells. However, researchers have not clearly determined whether GNE-477 produces antitumor effects on GBM. In the present study, GNE-477 significantly inhibited the proliferation, migration and invasion of U87 and U251 cells. In addition, GNE-477 also induced apoptosis of GBM cells, arresting the cell cycle in G0/G1 phase. More importantly, GNE-477 also reduced the levels of AKT and mTOR phosphorylation in the AKT/mTOR signaling pathway in a concentration-dependent manner. An increase in AKT activity induced by SC79 rescued the GNE-477-mediated inhibition of GBM cell proliferation and apoptosis. The antitumor effects of GNE-477 and the regulatory effects on related molecules were further confirmed in vivo using a nude mouse intracranial xenograft model. In conclusion, our study indicated that GNE-477 exerted significant antitumor effects on GBM cells in vitro and in vivo by downregulating the AKT/mTOR pathway.

SREBP1 site 1 protease inhibitor PF-429242 suppresses renal cell carcinoma cell growth

Renal cell carcinoma (RCC) cells have increased lipogenesis and cholesterol synthesis. Sterol regulatory element-binding protein-1 (SREBP1) is cleaved by site 1 protease (S1P) to release the transcriptionally active amino-terminal domain. PF-429242 is a potent and competitive S1P inhibitor. We here tested its activity in RCC cells. In established and primary human RCC cells, PF-429242 potently inhibited cell proliferation, migration, and invasion. The S1P inhibitor provoked apoptosis activation in RCC cells. Furthermore, shRNA-mediated S1P silencing or CRISPR/Cas9-induced S1P knockout led to RCC cell growth inhibition and apoptosis activation. Conversely, ectopic overexpression of SREBP1 or S1P augmented RCC cell proliferation and migration. Daily i.v. injection of a single dose of PF-429242 robustly inhibited RCC xenograft growth in severe combined immunodeficiency mice. Additionally, intratumoral injection of S1P shRNA lentivirus inhibited RCC xenograft growth in mice. SREBP1, S1P, and its target gene low density lipoprotein receptor (LDLR) were significantly elevated in human RCC tissues. These results suggest that targeting S1P by PF-429242 inhibited RCC cell growth in vitro and in vivo.

Therapeutically actionable signaling node to rescue AURKA driven loss of primary cilia in VHL-deficient cells

Loss of primary cilia in cells deficient for the tumor suppressor von Hippel Lindau (VHL) arise from elevated Aurora Kinase A (AURKA) levels. VHL in its role as an E3 ubiquitin ligase targets AURKA for degradation and in the absence of VHL, high levels of AURKA result in destabilization of the primary cilium. We identified NVP-BEZ235, a dual PI3K/AKT and mTOR inhibitor, in an image-based high throughput screen, as a small molecule that restored primary cilia in VHL-deficient cells. We identified the ability of AKT to modulate AURKA expression at the transcript and protein level. Independent modulation of AKT and mTOR signaling decreased AURKA expression in cells confirming AURKA as a new signaling node downstream of the PI3K cascade. Corroborating these data, a genetic knockdown of AKT in cells deficient for VHL rescued the ability of these cells to ciliate. Finally, inhibition of AKT/mTOR using NVP-BEZ235 was efficacious in reducing tumor burden in a 786-0 xenograft model of renal cell carcinoma. These data highlight a previously unappreciated signaling node downstream of the AKT/mTOR pathway via AURKA that can be targeted in VHL-null cells to restore ciliogenesis.

PI3K/AKT/mTOR signalling pathway involvement in renal cell carcinoma pathogenesis (Review)

Renal cell carcinoma (RCC) accounts for over 90% of all renal malignancies, and mainly affects the male population. Obesity and smoking are involved in the pathogenesis of several systemic cancers including RCC. The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signalling pathway regulates cell growth, differentiation, migration, survival, angiogenesis, and metabolism. Growth factors, hormones, cytokine and many extracellular cues activate PI3K/AKT/mTOR. Dysregulation of this molecular pathway is frequently reported in human cancers including RCC and is associated with aggressive development and poor survival rate. mTOR is the master regulator of cell metabolism and growth, and is activated in many pathological processes such as tumour formation, insulin resistance and angiogenesis. mTOR inhibitors are used at present as drug therapy for RCC to inhibit cell proliferation, growth, survival, and the cell cycle. Temsirolimus and everolimus are two mTOR inhibitors that are currently used for the treatment of RCC. Drugs targeting the PI3K/AKT/mTOR signalling pathway may be one of the best therapeutic options for RCC.

Dual inhibition of DNA-PKcs and mTOR by CC-115 potently inhibits human renal cell carcinoma cell growth

CC-115 is a dual inhibitor of DNA-PKcs and mTOR, both are valuable therapeutic targets for renal cell carcinoma (RCC). Our results showed that CC-115 inhibited survival and proliferation of established RCC cell lines (786-O and A489) and primary human RCC cells. The dual inhibitor induced selective apoptosis activation in RCC cells, as compared to no cytotoxicity nor apoptotic effects toward normal renal epithelial cells. CC-115 inhibited DNA-PKcs and mTORC1/2 activation in RCC cells. It was however ineffective in DNA-PKcs-mTOR double knockout (DKO) 786-O cells. CC-115 induced feedback autophagy activation in RCC cells. Autophagy inhibitors or Beclin-1/Light chain 3 (LC3) silencing potentiated CC-115-induced anti-RCC cell activity. Conversely, ectopic overexpression of Beclin-1 inhibited CC-115-induced cytotoxicity. At last CC-115 oral administration inhibited 786-O subcutaneous xenograft growth in nude mice. Taken together, dual inhibition of DNA-PKcs and mTOR by CC-115 potently inhibited RCC cell growth.