Cerebral organoid and mouse models reveal a RAB39b-PI3K-mTOR pathway-dependent dysregulation of cortical development leading to macrocephaly/autism phenotypes.

Dysregulation of early neurodevelopment is implicated in macrocephaly/autism disorders. However, the mechanism underlying this dysregulation, particularly in human cells, remains poorly understood. Mutations in the small GTPase gene RAB39b are associated with X-linked macrocephaly, autism spectrum disorder (ASD), and intellectual disability. The in vivo roles of RAB39b in the brain remain unknown. We generated Rab39b knockout (KO) mice and found that they exhibited cortical neurogenesis impairment, macrocephaly, and hallmark ASD behaviors, which resembled patient phenotypes. We also produced mutant human cerebral organoids that were substantially enlarged due to the overproliferation and impaired differentiation of neural progenitor cells (NPCs), which resemble neurodevelopmental deficits in KO mice. Mechanistic studies reveal that RAB39b interacts with PI3K components and its deletion promotes PI3K-AKT-mTOR signaling in NPCs of mouse cortex and cerebral organoids. The mTOR activity is robustly enhanced in mutant outer radial glia cells (oRGs), a subtype of NPCs barely detectable in rodents but abundant in human brains. Inhibition of AKT signaling rescued enlarged organoid sizes and NPC overproliferation caused by RAB39b mutations. Therefore, RAB39b mutation promotes PI3K-AKT-mTOR activity and alters cortical neurogenesis, leading to macrocephaly and autistic-like behaviors. Our studies provide new insights into neurodevelopmental dysregulation and common pathways associated with ASD across species.

Exogenous GDNF promotes peripheral facial nerve regeneration in rats through the PI3K/AKT/mTOR signaling pathway.

Facial nerve regeneration still lacks a well-defined and practical clinical intervention. The survival of central facial motoneuron is a critical component in the successful peripheral facial nerve regeneration. Endogenous GDNF is vital for facial nerve regeneration according to earlier investigations. Nevertheless, the low endogenous GDNF level makes it challenging to achieve therapeutic benefits. Thus, we crushed the main trunk of facial nerve in SD rats to provide a model of peripheral facial paralysis, and we administered exogenous GDNF and Rapa treatments. We observed changes in the animal behavior scores, the morphology of facial nerve and buccinator muscle, the electrophysiological of facial nerve, and the expression of GDNF, GAP-43, and PI3K/AKT/mTOR signaling pathway-related molecules in the facial motoneurons. We discovered that GDNF could boost axon regeneration, hasten the recovery of facial paralysis symptoms and nerve conduction function, and increase the expression of GDNF, GAP-43, and PI3K/AKT/mTOR signaling pathway-related molecules in the central facial motoneurons. Therefore, exogenous GDNF injection into the buccinator muscle can enhance facial nerve regeneration following crushing injury and protect facial neurons via the PI3K/AKT/mTOR signaling pathway. This will offer a fresh perspective and theoretical foundation for the management of clinical facial nerve regeneration.

STRIP2 is regulated by the transcription factor Sp1 and promotes lung adenocarcinoma progression via activating the PI3K/AKT/mTOR/MYC signaling pathway.

BACKGROUND: Patients with lung adenocarcinoma (LUAD) generally have poor prognosis. The role of striatin-interacting protein 2 (STRIP2) in LUAD remain unclear. METHODS: Liquid chromatography-mass spectrometry analyses were used to screen the STRIP2-binding proteins and co-immunoprecipitation verified these interactions. A dual luciferase reporter assay explored the transcription factor activating STRIP2 transcription. Xenograft and lung metastasis models assessed STRIP2's role in tumor growth and metastasis in vivo. RESULTS: STRIP2 is highly expressed in LUAD tissues and is linked to poor prognosis. STRIP2 expression in LUAD cells significantly promoted cell proliferation, invasion, and migration in vitro and in vivo. Mechanistically, STRIP2 boosted the PI3K/AKT/mTOR/MYC cascades by binding AKT. In addition, specificity protein 1, potently activated STRIP2 transcription by binding to the STRIP2 promoter. Blocking STRIP2 reduces tumor growth and lung metastasis in xenograft models. CONCLUSIONS: Our study identifies STRIP2 is a key driver of LUAD progression and a potential therapeutic target.

KIRREL promotes the proliferation of gastric cancer cells and angiogenesis through the PI3K/AKT/mTOR pathway.

Anti-angiogenesis is a promising therapeutic strategy for delaying tumour progression that offers, new hope for gastric cancer targeted therapy. The purpose of this study was to investigate the precise mechanism by which Kin of IRRE-like protein 1 (KIRREL) contributes to the development of gastric cancer, particularly in terms of tumour angiogenesis. Differential expression of KIRREL in tissues and cells was detected using quantitative real-time polymerase chain reaction, western blotting and immunohistochemistry. A bioinformatics analysis was conducted to screen for the function and pathway enrichment of KIRREL in gastric cancer. Lentivirus-induced KIRREL silencing in SNU-5 cells and lentivirus-induced KIRREL overexpression in AGS cells were used to study the effect of KIRREL on the proliferation, cell cycle and angiogenesis of gastric cancer cells. Moreover, the expressions of PI3K, P-PI3K, AKT, P-AKT, mTOR, P-mTOR, HIF-1α and VEGF were also detected. Gastric cancer tissues and cells had high levels of KIRREL expression, which is associated with the proliferation, cell cycle and angiogenesis of gastric cancer cells. After silencing and overexpressing KIRREL in SNU-5 and AGS cells, respectively, the proliferation and angiogenesis of SNU-5 cells were inhibited, while the proliferation and angiogenesis of AGS cells were promoted. According to a bioinformatics analysis of the KIRREL gene, angiogenesis regulation and the PI3K/AKT pathway were highly connected. The PI3K/AKT/mTOR pathway was repressed and stimulated by KIRREL silencing and overexpression, respectively. IGF-1, an AKT agonist, and LY294002, an inhibitor, reversed the effects of KIRREL silencing and overexpression on the PI3K/AKT/mTOR pathway and on gastric cancer cell proliferation and angiogenesis. KIRREL may mediate the proliferation and angiogenesis of gastric cancer cells through the PI3K/AKT/mTOR signalling pathway. These findings could help in the further development of potential anti-angiogenesis targets.

Plumbagin ameliorates LPS-induced acute lung injury by regulating PI3K/AKT/mTOR and Keap1-Nrf2/HO-1 signalling pathways.

Acute lung injury (ALI) is a major pathophysiological problem characterized by severe inflammation, resulting in high morbidity and mortality. Plumbagin (PL), a major bioactive constituent extracted from the traditional Chinese herb Plumbago zeylanica, has been shown to possess anti-inflammatory and antioxidant pharmacological activities. However, its protective effect on ALI has not been extensively studied. The objective of this study was to investigate the protective effect of PL against ALI induced by LPS and to elucidate its possible mechanisms both in vivo and in vitro. PL treatment significantly inhibited pathological injury, MPO activity, and the wet/dry ratio in lung tissues, and decreased the levels of inflammatory cells and inflammatory cytokines TNF-α, IL-1ß, IL-6 in BALF induced by LPS. In addition, PL inhibited the activation of the PI3K/AKT/mTOR signalling pathway, increased the activity of antioxidant enzymes CAT, SOD, GSH and activated the Keap1/Nrf2/HO-1 signalling pathway during ALI induced by LPS. To further assess the association between the inhibitory effects of PL on ALI and the PI3K/AKT/mTOR and Keap1/Nrf2/HO-1 signalling, we pretreated RAW264.7 cells with 740Y-P and ML385. The results showed that the activation of PI3K/AKT/mTOR signalling reversed the protective effect of PL on inflammatory response induced by LPS. Moreover, the inhibitory effects of PL on the production of inflammatory cytokines induced by LPS also inhibited by downregulating Keap1/Nrf2/HO-1 signalling. In conclusion, the results indicate that the PL ameliorate LPS-induced ALI by regulating the PI3K/AKT/mTOR and Keap1-Nrf2/HO-1 signalling, which may provide a novel therapeutic perspective for PL in inhibiting ALI.

Inhibitory effects of medium-chain fatty acids on the proliferation of human breast cancer cells via suppression of Akt/mTOR pathway and modulating the Bcl-2 family protein.

Medium-chain fatty acids (MCFAs) have 6-12 carbon atoms and are instantly absorbed into the bloodstream before traveling to the portal vein and the liver, where they are immediately used for energy and may have antitumor effects. Its role in breast cancer is poorly understood. To investigate the apoptosis-inducing effect of MCFAs in breast cancer cells, cell viability assay, colony formation assay, cell migration assay, cell invasion assay, nuclear morphology, cell cycle assay, intracellular reactive oxygen species (ROS), matrix metalloproteinase (MMP), apoptosis, RT-qPCR analysis, and Western blot analysis were performed. In the present study, MCFA treatments reduced proliferative capability, increased ROS level, increased the depletion of MMP, induced G0/G1 and S phase cell cycle arrest, and late apoptosis of breast cancer cells in an effective concentration. Besides, MCFA treatment contributed to the upregulation of proapoptotic protein (BAK) and caspase-3, and the downregulation of antiapoptotic protein (Bcl-2). Mechanistically, phosphorylation levels of EGFR, Akt, and mTOR were significantly reduced in breast cancer cells treated with MCFAs. However, no significant changes in apoptosis and signaling-related proteins were observed in lauric acid-treated ER-positive cancer cells. Our findings suggested that MCFAs suppressed breast cancer cell proliferation by modulating the PI3K/Akt/mTOR signaling pathway. MCFAs may be a promising therapeutic drug for treating breast cancer.

CircTRIM1 encodes TRIM1-269aa to promote chemoresistance and metastasis of TNBC via enhancing CaM-dependent MARCKS translocation and PI3K/AKT/mTOR activation.

Peptides and proteins encoded by noncanonical open reading frames (ORFs) of circRNAs have recently been recognized to play important roles in disease progression, but the biological functions and mechanisms of these peptides and proteins are largely unknown. Here, we identified a potential coding circular RNA, circTRIM1, that was upregulated in doxorubicin-resistant TNBC cells by intersecting transcriptome and translatome RNA-seq data, and its expression was correlated with clinicopathological characteristics and poor prognosis in patients with TNBC. CircTRIM1 possesses a functional IRES element along with an 810 nt ORF that can be translated into a novel endogenously expressed protein termed TRIM1-269aa. Functionally, we demonstrated that TRIM1-269aa, which is involved in the biological functions of circTRIM1, promoted chemoresistance and metastasis in TNBC cells both in vitro and in vivo. In addition, we found that TRIM1-269aa can be packaged into exosomes and transmitted between TNBC cells. Mechanistically, TRIM1-269aa enhanced the interaction between MARCKS and calmodulin, thus promoting the calmodulin-dependent translocation of MARCKS, which further initiated the activation of the PI3K/AKT/mTOR pathway. Overall, circTRIM1, which encodes TRIM1-269aa, promoted TNBC chemoresistance and metastasis by enhancing MARCKS translocation and PI3K/AKT/mTOR activation. Our investigation has yielded novel insights into the roles of protein-coding circRNAs and supported circTRIM1/TRIM1-269aa as a novel promising prognostic and therapeutic target for patients with TNBC.

Unveiling the role of UPF3B in hepatocellular carcinoma: Potential therapeutic target.

RNA-binding proteins can regulate nucleotide metabolism and gene expression. UPF3B regulator of nonsense mediated mRNA decay (UPF3B) exhibits dysfunction in cancers. However, its role in the progression of hepatocellular carcinoma (HCC) is still insufficiently understood. Here, we found that UPF3B was markedly upregulated in HCC samples and associated with adverse prognosis in patients. UPF3B dramatically promoted HCC growth both in vivo and in vitro. Mechanistically, UPF3B was found to bind to PPP2R2C, a regulatory subunit of PP2A, boosting its mRNA degradation and activating the PI3K/AKT/mTOR pathway. E2F transcription factor 6 (E2F6) directly binds to the UPF3B promoter to facilitate its transcription. Together, the E2F6/UPF3B/PPP2R2C axis promotes HCC growth through the PI3K/AKT/mTOR pathway. Hence, it could be a promising therapeutic target for treating HCC.

FAT10 induces immune suppression by upregulating PD-L1 expression in hepatocellular carcinoma.

The upregulation of programmed death ligand 1 (PD-L1) plays a crucial role in facilitating cancer cells to evade immune surveillance through immunosuppression. However, the precise regulatory mechanisms of PD-L1 in hepatocellular carcinoma (HCC) remain undefined. The correlation between PD-L1 and ubiquitin-like molecules (UBLs) was studied using sequencing data from 20 HCC patients in our center, combined with TCGA data. Specifically, the association between FAT10 and PD-L1 was further validated at both the protein and mRNA levels in HCC tissues from our center. Subsequently, the effect of FAT10 on tumor progression and immune suppression was examined through both in vivo and in vitro experiments. Utilizing sequencing data, qPCR, and Western blotting assays, we confirmed that FAT10 was highly expressed in HCC tissues and positively correlated with PD-L1 expression. Additionally, in vitro experiments demonstrated that the overexpression of FAT10 fostered the proliferation, migration, and invasion of HCC cells. Furthermore, the overexpression of FAT10 in HCC cells led to an increase in PD-L1 expression, resulting in the inhibition of T cell proliferation and the enhancement of HCC cell resistance to T cell-mediated cytotoxicity. Moreover, in vivo experiments utilizing the C57BL/6 mouse model revealed that overexpression of FAT10 effectively suppressed the infiltration of CD8 + GZMB + and CD8 + Ki67 + T cells, as well as reduced serum levels of TNF-α and IFN-γ. Mechanistically, we further identified that FAT10 upregulates PD-L1 expression via activating the PI3K/AKT/mTOR pathway, but not in a ubiquitin-like modification. In conclusion, our findings indicate that FAT10 promotes immune evasion of HCC via upregulating PD-L1 expression, suggesting its potential as a novel target to enhance the efficiency of immunotherapy in HCC.

Transcriptome data-based status of PI3K/AKT/mTOR pathway indicates heterogeneity and immune modulation in patients with pancreatic ductal adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer with limited treatment options. The PI3K/AKT/mTOR pathway is commonly activated in PDAC and plays a critical role in its progression. METHODS AND RESULTS: In this study, the effect of taselisib (a selective PI3K inhibitor) on PDAC cell proliferation was investigated, and a significant decrease in viability was observed with increasing concentrations of taselisib. Differential analysis on samples from the Genotype-Tissue Expression and The Cancer Genome Atlas databases revealed 24 dysregulated PI3K/AKT/mTOR pathway-related genes (PRGs). Unsupervised clustering-based analysis of transcriptome cohorts revealed two clusters with high consistency between RNA-seq and microarray cohorts. Cluster B had higher enrichment of immune cells, particularly CD8+ T cells, and lower levels of immunosuppressive Treg cells. Moreover, we investigated the relationship between drug sensitivity and different clusters and found that cluster A had a better response to PI3K/AKT/mTOR pathway-related inhibitors and chemotherapy. Finally, cluster A exhibited significant activation of PI3K/AKT/mTOR and related oncogenic pathways, contributing to poor prognosis. The study also developed a risk score based on the expression profiles of PRGs and machine learning, which showed a significant increase in overall survival time among patients in the low-risk group. Importantly, the PI3K/AKT/mTOR pathway could be used to better predict individual risk scores, as evidenced by stratified survival analysis. CONCLUSIONS: These findings suggest that targeting the PI3K/AKT/mTOR pathway may have therapeutic potential in PDAC, and distinct pathway states, immune modulation and tumor microenvironments have prognostic value.

Single-cell RNA sequencing reveals the mechanism of PI3K/AKT/mTOR signaling pathway activation in lung adenocarcinoma by KRAS mutation.

BACKGROUND: Aberrant activation of the phosphatidlinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway has been shown to play an important role in lung adenocarcinoma (LUAD). The effect of KRAS mutations, one of the important signatures of LUAD, on the PI3K/AKT/mTOR pathway in LUAD remains unclear. METHODS: The Seurat package and principal component analysis were used for cell categorization of single-cell RNA sequencing data of LUAD. The AUCell score was used to assess the activity of the PI3K/AKT/mTOR pathway. Meanwhile, using the gene expression profiles and mutation profiles in the The Cancer Genome Atlas dataset, LUAD patients were categorized into KRAS-mutant (KRAS-MT) and KRAS-wild-types (KRAS-WT), and the corresponding enrichment scores were calculated using gene set enrichment analysis analysis. Finally, the subpopulation of cells with the highest pathway activity was identified, the copy number variation profile of this subpopulation was inscribed using the inferCNV package and the CMap database was utilized to make predictions for drugs targeting this subpopulation. RESULTS: There is higher PI3K/AKT/mTOR pathway activity in LUAD epithelial cells with KRAS mutations, and high expression of KRAS, PIK3CA, AKT1 and PDPK1. In particular, we found significantly higher levels of pathway activity and associated gene expression in KRAS-MT than in KRAS-WT. We identified the highest pathway activity on a subpopulation of GRB2+ epithelial cells and the presence of amplified genes within its pathway. Finally, drugs were able to target GRB2+ epithelial cell subpopulations, such as wortmannin, palbociclib and angiogenesis inhibitor. CONCLUSIONS: The present study provides a basic theory for the activation of the PI3K/AKT/mTOR signaling pathway as a result of KRAS mutations.

AURKB targets DHX9 to promote hepatocellular carcinoma progression via PI3K/AKT/mTOR pathway.

Aurora kinase B (AURKB) is known to play a carcinogenic role in a variety of cancers, but its underlying mechanism in liver cancer is unknown. This study aimed to investigate the role of AURKB in hepatocellular carcinoma (HCC) and its underlying molecular mechanism. Bioinformatics analysis revealed that AURKB was significantly overexpressed in HCC tissues and cell lines, and its high expression was associated with a poorer prognosis in HCC patients. Furthermore, downregulation of AURKB inhibited HCC cell proliferation, migration, and invasion, induced apoptosis, and caused cell cycle arrest. Moreover, AURKB downregulation also inhibited lung metastasis of HCC. AURKB interacted with DExH-Box helicase 9 (DHX9) and targeted its expression in HCC cells. Rescue experiments further demonstrated that AURKB targeting DHX9 promoted HCC progression through the PI3K/AKT/mTOR pathway. Our results suggest that AURKB is significantly highly expressed in HCC and correlates with patient prognosis. Targeting DHX9 with AURKB promotes HCC progression via the PI3K/AKT/mTOR pathway.

The FOXO1/G6PC axis promotes gastric cancer progression and mediates 5-fluorouracil resistance by targeting the PI3K/AKT/mTOR signaling pathway.

Gastric cancer (GC) is a prevalent malignancy of the digestive system. Distant metastasis and chemotherapy resistance are the crucial obstacles to prognosis in GC. Recent research has discovered that the glucose-6-phosphatase catalytic subunit (G6PC) plays an important role in tumor malignant development. However, little evidence has highlighted its role in GC. Herein, through a comprehensive analysis including profiling of tissue samples and functional validation in vivo and in vitro, we identify G6PC as a crucial factor in GC tumorigenesis. Importantly, we found that the FOXO1/G6PC axis could accelerate GC cell proliferation, metastasis, and 5-Fluorouracil (5-FU) resistance by targeting the PI3K/AKT/mTOR signaling pathway, implicating that as a prospective therapeutic approach in GC.

Novel cellular systems unveil mucosal melanoma initiating cells and a role for PI3K/Akt/mTOR pathway in mucosal melanoma fitness.

BACKGROUND: Mucosal Melanomas (MM) are highly aggressive neoplasms arising from mucosal melanocytes. Current treatments offer a limited survival benefit for patients with advanced MM; moreover, the lack of pre-clinical cellular systems has significantly limited the understanding of their immunobiology. METHODS: Five novel cell lines were obtained from patient-derived biopsies of MM arising in the sino-nasal mucosa and designated as SN-MM1-5. The morphology, ultrastructure and melanocytic identity of SN-MM cell lines were validated by transmission electron microscopy and immunohistochemistry. Moreover, in vivo tumorigenicity of SN-MM1-5 was tested by subcutaneous injection in NOD/SCID mice. Molecular characterization of SN-MM cell lines was performed by a mass-spectrometry proteomic approach, and their sensitivity to PI3K chemical inhibitor LY294002 was validated by Akt activation, measured by pAkt(Ser473) and pAkt(Thr308) in immunoblots, and MTS assay. RESULTS: This study reports the validation and functional characterization of five newly generated SN-MM cell lines. Compared to the normal counterpart, the proteomic profile of SN-MM is consistent with transformed melanocytes showing a heterogeneous degree of melanocytic differentiation and activation of cancer-related pathways. All SN-MM cell lines resulted tumorigenic in vivo and display recurrent structural variants according to aCGH analysis. Of relevance, the microscopic analysis of the corresponding xenotransplants allowed the identification of clusters of MITF-/CDH1-/CDH2 + /ZEB1 + /CD271 + cells, supporting the existence of melanoma-initiating cells also in MM, as confirmed in clinical samples. In vitro, SN-MM cell lines were sensitive to cisplatin, but not to temozolomide. Moreover, the proteomic analysis of SN-MM cell lines revealed that RICTOR, a subunit of mTORC2 complex, is the most significantly activated upstream regulator, suggesting a relevant role for the PI3K-Akt-mTOR pathway in these neoplasms. Consistently, phosphorylation of NDRG1 and Akt activation was observed in SN-MM, the latter being constitutive and sustained by PTEN loss in SN-MM2 and SN-MM3. The cell viability impairment induced by LY294002 confirmed a functional role for the PI3K-Akt-mTOR pathway in SN-MM cell lines. CONCLUSIONS: Overall, these novel and unique cellular systems represent relevant experimental tools for a better understanding of the biology of these neoplasms and, as an extension, to MM from other sites.

Hypoxia upregulating ACSS2 enhances lipid metabolism reprogramming through HMGCS1 mediated PI3K/AKT/mTOR pathway to promote the progression of pancreatic neuroendocrine neoplasms.

BACKGROUND: Pancreatic neuroendocrine neoplasms (pNENs) are relatively rare. Hypoxia and lipid metabolism-related gene acetyl-CoA synthetase 2 (ACSS2) is involved in tumor progression, but its role in pNENs is not revealed. This study showed that hypoxia can upregulate ACSS2, which plays an important role in the occurrence and development of pNENs through lipid metabolism reprogramming. However, the precise role and mechanisms of ACSS2 in pNENs remain unknown. METHODS: mRNA and protein levels of ACSS2 and 3-hydroxy-3-methylglutaryl-CoA synthase1 (HMGCS1) were detected using quantitative real-time PCR (qRT-PCR) and Western blotting (WB). The effects of ACSS2 and HMGCS1 on cell proliferation were examined using CCK-8, colony formation assay and EdU assay, and their effects on cell migration and invasion were examined using transwell assay. The interaction between ACSS2 and HMGCS1 was verified by Co-immunoprecipitation (Co-IP) experiments, and the functions of ACSS2 and HMGCS1 in vivo were determined by nude mouse xenografts. RESULTS: We demonstrated that hypoxia can upregulate ACSS2 while hypoxia also promoted the progression of pNENs. ACSS2 was significantly upregulated in pNENs, and overexpression of ACSS2 promoted the progression of pNENs and knockdown of ACSS2 and ACSS2 inhibitor (ACSS2i) treatment inhibited the progression of pNENs. ACSS2 regulated lipid reprogramming and the PI3K/AKT/mTOR pathway in pNENs, and ACSS2 regulated lipid metabolism reprogramming through the PI3K/AKT/mTOR pathway. Co-IP experiments indicated that HMGCS1 interacted with ACSS2 in pNENs. Overexpression of HMGCS1 can reverse the enhanced lipid metabolism reprogramming and tumor-promoting effects of knockdown of ACSS2. Moreover, overexpression of HMGCS1 reversed the inhibitory effect of knockdown of ACSS2 on the PI3K/AKT/mTOR pathway. CONCLUSION: Our study revealed that hypoxia can upregulate the lipid metabolism-related gene ACSS2, which plays a tumorigenic effect by regulating lipid metabolism through activating the PI3K/AKT/mTOR pathway. In addition, HMGCS1 can reverse the oncogenic effects of ACSS2, providing a new option for therapeutic strategy.

Melatonin effect on breast and ovarian cancers by targeting the PI3K/Akt/mTOR pathway.

Melatonin, the hormone of the pineal gland, possesses a range of physiological functions, and recently, its anticancer effect has become more apparent. A more thorough understanding of molecular alterations in the components of several signaling pathways as new targets for cancer therapy is needed because of current innate restrictions such as drug toxicity, side effects, and acquired or de novo resistance. The PI3K/Akt/mTOR pathway is overactivated in many solid tumors, such as breast and ovarian cancers. This pathway in normal cells is essential for growth, proliferation, and survival. However, it is an undesirable characteristic in malignant cells. We have reviewed multiple studies about the effect of melatonin on breast and ovarian cancer, focusing on the PI3K/Akt/mTOR pathway. Melatonin exerts its inhibitory effects via several mechanisms. A: Downregulation of downstream or upstream components of the signaling pathway such as phosphatase and tensin homolog (PTEN), phosphatidylinositol (3,4,5)-trisphosphate kinase (PI3K), p-PI3K, Akt, p-Akt, mammalian target of rapamycin (mTOR), and mTOR complex1 (mTORC1). B: Apoptosis induction by decreasing MDM2 expression, a downstream target of Akt, and mTOR, which leads to Bad activation in addition to Bcl-XL and p53 inhibition. C: Induction of autophagy in cancer cells via activating ULK1 after mTOR inhibition, resulting in Beclin-1 phosphorylation. Beclin-1 with AMBRA1 and VPS34 promotes PI3K complex I activity and autophagy in cancer cells. The PI3K/Akt/mTOR pathway overlaps with other intracellular signaling pathways and components such as AMP-activated protein kinase (AMPK), Wnt/ß-catenin, mitogen-activated protein kinase (MAPK), and other similar pathways. Cancer therapy can benefit from understanding how these pathways interact and how melatonin affects these pathways.

MSI2 regulates NLK-mediated EMT and PI3K/AKT/mTOR pathway to promote pancreatic cancer progression.

BACKGROUND: The incidence of pancreatic cancer is increasing by years, and the 5-year survival rate is very low. Our team have revealed that Musashi2 (MSI2) could promote aggressive behaviors in pancreatic cancer by downregulating Numb and p53. MSI2 also facilitates EMT in pancreatic cancer induced by EGF through the ZEB1-ERK/MAPK signaling pathway. This study aims to further explore the molecular mechanisms of MSI2-regulated downstream pathways in pancreatic cancer. METHODS: In vitro and in vivo experiments were conducted to investigate the role and mechanism of MSI2 in promoting malignant behaviors of pancreatic cancer through regulation of NLK. RESULTS: Genes closely related to MSI2 were screened from the GEPIA and TCGA databases. We found that NLK showed the most significant changes in mRNA levels with consistent changes following MSI2 interference and overexpression. The high correlation between MSI2 and NLK was also observed at the protein level. Multivariate analysis revealed that both MSI2 and NLK were independent adverse indicators of survival in pancreatic cancer patients, as well as join together. In vitro, silencing or overexpressing NLK altered cell invasion and migration, by regulating EMT and the PI3K-AKT-mTOR pathway. Silencing MSI2 reduced protein expression in the EMT and PI3K-AKT-mTOR pathways, leading to decreased cell invasion and migration abilities, while these effects could be reversed by overexpression of NLK. In vivo, MSI2 silencing inhibited liver metastasis, which could be reversed by overexpressing NLK. Mechanistically, MSI2 directly binds to the translation regulatory region of NLK mRNA at positions 79-87 nt, enhancing its transcriptional activity and exerting post-transcriptional regulatory roles. The analysis of molecular docking showed the close relationship between MSI2 and NLK in pancreatic cancer patients. CONCLUSIONS: Our findings elucidate the regulatory mechanisms of the MSI2-NLK axis in modulating aggressive behaviors of pancreatic cancer cells, which providing new evidence for therapeutic strategies in pancreatic cancer.

Flavokawain C inhibits glucose metabolism and tumor angiogenesis in nasopharyngeal carcinoma by targeting the HSP90B1/STAT3/HK2 signaling axis.

OBJECTIVE: Over the past decade, heat shock protein 90 (HSP90) inhibitors have emerged as promising anticancer drugs in solid and hematological malignancies. Flavokawain C (FKC) is a naturally occurring chalcone that has been found to exert considerable anti-tumor efficacy by targeting multiple molecular pathways. However, the efficacy of FKC has not been studied in nasopharyngeal carcinoma (NPC). Metabolic abnormalities and uncontrolled angiogenesis are two important features of malignant tumors, and the occurrence of these two events may involve the regulation of HSP90B1. Therefore, this study aimed to explore the effects of FKC on NPC proliferation, glycolysis, and angiogenesis by regulating HSP90B1 and the underlying molecular regulatory mechanisms. METHODS: HSP90B1 expression was analyzed in NPC tissues and its relationship with patient's prognosis was further identified. Afterward, the effects of HSP90B1 on proliferation, apoptosis, glycolysis, and angiogenesis in NPC were studied by loss-of-function assays. Next, the interaction of FKC, HSP90B1, and epidermal growth factor receptor (EGFR) was evaluated. Then, in vitro experiments were designed to analyze the effect of FKC treatment on NPC cells. Finally, in vivo experiments were allowed to investigate whether FKC treatment regulates proliferation, glycolysis, and angiogenesis of NPC cells by HSP90B1/EGFR pathway. RESULTS: HSP90B1 was highly expressed in NPC tissues and was identified as a poor prognostic factor in NPC. At the same time, knockdown of HSP90B1 can inhibit the proliferation of NPC cells, trigger apoptosis, and reduce glycolysis and angiogenesis. Mechanistically, FKC affects downstream EGFR phosphorylation by regulating HSP90B1, thereby regulating the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway. FKC treatment inhibited the proliferation, glycolysis, and angiogenesis of NPC cells, which was reversed by introducing overexpression of HSP90B1. In addition, FKC can affect NPC tumor growth and metastasis in vivo by regulating the HSP90B1/EGFR pathway. CONCLUSION: Collectively, FKC inhibits glucose metabolism and tumor angiogenesis in NPC by targeting the HSP90B1/EGFR/PI3K/Akt/mTOR signaling axis.

SULF1 regulates malignant progression of colorectal cancer by modulating ARSH via FAK/PI3K/AKT/mTOR signaling.

BACKGROUND: Colorectal cancer (CRC) has the third highest incidence and second mortality rate of malignant tumors globally, highlighting the urgency to explore the mechanisms underlying CRC progression for refined treatment of this patient population. METHODS: R Studio was used for data sorting and analysis. Cell apoptosis and cell cycle detection were performed by flow cytometry. Quantitative real-time PCR (qRT-PCR) was used to explore mRNA expression levels. Western blotting was used to explore protein expression levels. CCK8, EdU, and colony formation assays were performed to explore the proliferation capacity of CRC cells. Transwell invasion and migration assays, along with the wound healing assay, were used to explore the invasive and migratory abilities of CRC cells. Subcutaneous Xenograft Assay was utilized to evaluate the tumorigenic capacity of CRC cells in vivo. RESULTS: SULF1 was highly expressed in CRC samples and cell lines. The knockdown of SULF1 inhibited the proliferation, invasion, and migration of CRC and increased the rate of cell apoptosis. Meanwhile, we demonstrated that SULF1 could negatively regulate ARSH through the FAK/PI3K/AKT/mTOR pathway. CONCLUSION: We demonstrated that SULF1 could promote CRC progression by regulating ARSH. The SULF1/ARSH/FAK/PI3K/AKT/mTOR signaling pathway represents a promising target for the treatment of this patient population. Colorectal cancer (CRC) has the third highest incidence and second mortality rate of malignant tumors globally. Sulfatase 1 (SULF1) belongs to the sulfatase family, The function of SULF1 in CRC remains elusive. Our study demonstrated that the knockdown of SULF1 could inhibit the proliferation, invasion, and migration of CRC. Meanwhile, our findings indicated that SULF1 could interact with Arylsulfatase Family Member H (ARSH) to regulate the proliferation, invasion, and migration of CRC via the FAK/PI3K/AKT/mTOR signaling pathway. Taken together, our findings suggest that SULF1 might be a new therapeutic target in CRC.

TGFBI promotes proliferation and epithelial-mesenchymal transition in renal cell carcinoma through PI3K/AKT/mTOR/HIF-1α pathway.

BACKGROUND: Renal cell carcinoma (RCC) is presently recognized as the most prevalent kidney tumor. However, the role and underlying mechanism of action of the conversion factor-inducible protein (TGFBI), an extracellular matrix protein, in RCC remain poorly understood. METHODS: In this study, we employed Western blot, quantitative real-time polymerase chain reaction (qRT-PCR), and immunohistochemistry techniques to assess the expression of TGFBI in RCC tissues or cells. Furthermore, we analyzed the proliferation and migration of RCC cells using CCK8, cloning, scratching, and migration assays. Additionally, we examined apoptosis and cell cycle progression through flow cytometry, analysis. Lastly, we employed gene set enrichment analysis (GSEA) to investigate the biological processes associated with TGFBI, which were subsequently validated. RESULTS: The findings indicate that TGFBI exhibits significantly elevated expression levels in both renal cell carcinoma (RCC) tissues and cells. Furthermore, the knockdown of TGFBI in SiRNA transfected cells resulted in the inhibition of RCC cell proliferation, migration, invasiveness, apoptosis, and alteration of the cell cycle. Additionally, TGFBI was found to impede the epithelial-mesenchymal transition (EMT) process in RCC cells. Bioinformatics analysis suggests that TGFBI may exert its influence on various biological processes in RCC through the tumor immune microenvironment. Moreover, our study demonstrates that TGFBI promotes RCC progression by activating the PI3K/AKT/mTOR/HIF-1α. CONCLUSIONS: Our research indicates that TGFBI exhibits high expression in RCC and facilitate RCC progression and metastasis through various molecular mechanisms. Hence, TGFBI has the potential to be a novel therapeutic target for the diagnosis and treatment of RCC in the future.