Triptonide inhibits human nasopharyngeal carcinoma cell growth via disrupting Lnc-RNA THOR-IGF2BP1 signaling

The therapeutic value of SC66 in human renal cell carcinoma cells

The PI3K-AKT-mTOR cascade is required for renal cell carcinoma (RCC) progression. SC66 is novel AKT inhibitor. We found that SC66 inhibited viability, proliferation, migration and invasion of RCC cell lines (786-O and A498) and patient-derived primary RCC cells. Although SC66blocked AKT-mTORC1/2 activation in RCC cells, it remained cytotoxic in AKT-inhibited/-silenced RCC cells. In RCC cells, SC66 cytotoxicity appears to occur via reactive oxygen species (ROS) production, sphingosine kinase 1inhibition, ceramide accumulation and JNK activation, independent of AKT inhibition. The ROS scavenger N-acetylcysteine, the JNK inhibitor (JNKi) and the anti-ceramide sphingolipid sphingosine-1-phosphate all attenuated SC66-induced cytotoxicity in 786-O cells. In vivo, oral administration of SC66 potently inhibited subcutaneous 786-O xenograft growth in SCID mice. AKT-mTOR inhibition, SphK1 inhibition, ceramide accumulation and JNK activation were detected in SC66-treated 786-O xenograft tumors, indicating that SC66 inhibits RCC cell progression through AKT-dependent and AKT-independent mechanisms.

I-BET726 suppresses human skin squamous cell carcinoma cell growth in vitro and in vivo

Bromodomain-containing protein 4 (BRD4) is a potential therapeutic target of skin squamous cell carcinoma (SCC). I-BET726 is a novel BRD4 inhibitor. Its potential effect in skin SCC cells was tested in the present study. We show that I-BET726 potently inhibited survival, proliferation, cell cycle progression, and migration in established (A431/SCC-9/SCC-12/SCC-13 lines) and primary human skin SCC cells. I-BET726 induced significant apoptosis activation in skin SCC cells. It was more efficient in inhibiting skin SCC cells than known BRD4 inhibitors (JQ1, CPI203, and AZD5153). I-BET726 not only downregulated BRD4-regulated proteins (c-Myc, Bcl-2, and cyclin D1), but also inhibited sphingosine kinase 1 (SphK1) and Akt signalings in SCC cells. Restoring Akt activation, by a constitutively active S473D mutant Akt1 (“caAkt1”), partially inhibited I-BET726-induced cytotoxicity in A431 cells. In vivo, I-BET726 oral administration potently inhibited A431 xenograft growth in severe combined immunodeficient mice. Downregulation of BRD4-regulated proteins and inhibition of the SphK1-Akt signaling were detected in I-BET726-treated A431 xenograft tumor tissues. Together, I-BET726 inhibits skin SCC cell growth in vitro and in vivo.

The therapeutic value of the SphK1-targeting microRNA-3677 in human osteosarcoma cells

Sphingosine kinase 1 (SphK1) is a potential therapeutic target for human osteosarcoma (OS). SphK1-targeting microRNAs (miRNAs) could have important therapeutic value for OS. We discovered that micorRNA-3677 (miR-3677) is a SphK1-targeting miRNA, inhibiting OS cell progression. The results of RNA-Pull down assay confirmed direct binding between biotinylated-miR-3677 and SphK1 mRNA in primary human OS cells. In established and primary human OS cells forced overexpression of miR-3677, by a lentiviral construct, decreased SphK1 3’-UTR (untranslated region) activity and downregulated SphK1 expression. Both were however enhanced with miR-3677 inhibition in OS cells. Function studies demonstrated that OS cell growth, proliferation and migration were inhibited with miR-3677 overexpression, but augmented with miR-3677 inhibition. MiR-3677 overexpression-induced anti-OS cell activity was reversed with re-expression of the 3’-UTR-depleted SphK1. Additionally, in SphK1 knockout OS cells (by CRISPR/Cas9 strategy), altering miR-3677 expression failed to further alter cell functions. Finally, we show that miR-3677 expression was significantly downregulated in primary human OS tissues, correlating with SphK1 mRNA upregulation. We conclude that targeting SphK1 by miR-3677 inhibits human OS cell progression.

LncRNA KCNQ1OT1 regulates microRNA-9-LMX1A expression and inhibits gastric cancer cell progression

LMX1A (LIM homeobox transcription factor 1α) is a tumor suppressor protein. Our previous study has shown that microRNA-9 (“miR-9”), being upregulated in human gastric cancer (GC), targets LMX1A to promote GC cell progression. Through searching long non-coding RNA (LncRNA) database, we identified that LncRNA KCNQ1OT1 is the competing endogenous RNA (ceRNA) of miR-9. KCNQ1OT1 putatively targets miR-9. Its level is downregulated in human GC tissues. In AGS cells and primary human GC cells, forced overexpression of KCNQ1OT1, by a lentiviral construct, induced miR-9 downregulation and LMX1A upregulation. Furthermore, KCNQ1OT1 overexpression inhibited GC cell survival, proliferation, migration and invasion, but inducing apoptosis activation. Contrarily, KCNQ1OT1 silencing, by targeted siRNAs, induced miR-9 accumulation and LMX1A downregulation. Consequently, GC cell proliferation, migration and invasion were enhanced. Importantly, KCNQ1OT1 overexpression or silencing was ineffective in LMX1A knockout AGC cells. Taken together, KCNQ1OT1 inhibits GC cell progression via regulating miR-9 and LMX1A expression.

Triptonide effectively suppresses gastric tumor growth and metastasis through inhibition of the oncogenic Notch1 and NF-κB signaling pathways

Gastric cancer ranks as the third leading cause of cancer-related death worldwide. The uncontrolled tumor growth and robust metastasis are key factors to cause the cancer patient death. Mechanistically, aberrant activation of Notch and NF-κB signaling pathways plays pivotal roles in the initiation and metastasis of gastric cancer. Despite great efforts have been made in recent decades, the effective drug against the advanced and metastatic gastric cancer is still lacking in the clinical setting. In this study, we found that triptonide, a small molecule (MW358) purified from the traditional Chinese medicinal herb Tripterygium wilfordii Hook F, effectively suppressed tumor growth and metastasis in xenograft mice without obvious toxicity at the doses we tested, resulting in potent anti-gastric cancer effect with low toxicity. Triptonide markedly inhibited human metastatic gastric cancer cell migration, invasion, proliferation, and tumorigenicity. Molecular mechanistic studies revealed that triptonide significantly reduced Notch1 protein levels in metastatic gastric cancer cells through degrading the oncogenic protein Notch1 via the ubiquitin-proteasome pathway. Consequently, the levels of Notch1 downstream proteins RBPJ, IKKα, IKKβ were significantly diminished, and nuclear factor-kappa B (NF-κB) phosphorylation was significantly reduced. Together, triptonide effectively suppresses gastric cancer growth and metastasis via inhibition of the oncogenic Notch1 and NF-κB signaling pathways. Our findings provide a new strategy and drug candidate for treatment of the advanced and metastatic gastric cancer.

LINC00682 inhibits gastric cancer cell progression via targeting microRNA-9-LMX1A signaling axis

microRNA-9 (“miR-9”), upregulated in human gastric cancer (GC) tissues, targets LMX1A (LIM homeobox transcription factor 1α) to promote GC cell progression. The underlying mechanism of miR-9 upregulation in GC is still unknown. Through searching multiple long non-coding RNA (LncRNA) databases, we here discovered that the long non-coding RNALINC00682 (long intergenic non-protein coding RNA 682) putatively targets miR-9. We show that ectopic overexpression of LINC00682 induced miR-9 downregulation but LMX1A upregulation, inhibiting AGS cell survival, proliferation, migration and invasion. Significant apoptosis activation was detected in LINC00682-overexpressed AGS cells. Contrarily, LINC00682 knockdown induced miR-9 upregulation but LMX1A downregulation, promoting AGS cell survival, proliferation, migration and invasion. In the primary human GC cells, forced LINC00682 overexpression similarly induced miR-9 downregulation and LMX1A upregulation, causing proliferation inhibition and apoptosis activation. Significantly, restoring miR-9 expression by a lentiviral construct reversed LINC00682-induced actions in GC cells. Furthermore, LINC00682 was ineffective in LMX1A KO AGS cells. Importantly, LINC00682 expression levels are significantly downregulated in human GC tissues. We conclude that LINC00682 inhibits GC cell progression via targeting miR-9-LMX1A signaling axis.

Ninjurin2 overexpression promotes glioma cell growth

Ninjurin2 (Ninj2) is an adhesion protein expressed in neurons and glial cells. The current study tested its expression and potential functions in human glioma. We show that Ninj2 mRNA and protein levels are significantly upregulated in human glioma cells and tissues. In established and primary human glioma cells, Ninj2 shRNA or knockout (by CRISPR/Cas9 gene editing) potently inhibited cell survival, growth, proliferation, cell migration and invasion, while inducing apoptosis activation. Contrarily, ectopic overexpression of Ninj2 promoted glioma cell progression in vitro. In human glioma tissues and cells, Ninj2 co-immunoprecipitated with multiple receptor tyrosine kinases (EGFR, PDGFRβ and FGFR), required for downstream Akt and Erk activation. Akt and Erk activation was potently inhibited by Ninj2 shRNA or knockout, but enhanced with ectopic Ninj2 overexpression in glioma cells. In summary, we show that Ninj2 overexpression promotes glioma cell growth.

Lnc-THOR silencing inhibits human glioma cell survival by activating MAGEA6-AMPK signaling

Long non-coding RNA THOR (Lnc-THOR) binds to IGF2BP1, essential for its function. We here show that Lnc-THOR is expressed in human glioma tissues and cells. Its expression is extremely low or even undetected in normal brain tissues, as well as in human neuronal cells and astrocytes. We show that Lnc-THOR directly binds to IGF2BP1 in established and primary human glioma cells. shRNA-mediated Lnc-THOR knockdown or CRISPR/Cas9-induced Lnc-THOR knockout potently inhibited cell survival and proliferation, while provoking glioma cell apoptosis. Contrarily, forced overexpression of Lnc-THOR promoted glioma cell growth and migration. Importantly, Lnc-THOR shRNA or knockout activated MAGEA6-AMPK signaling in glioma cells. AMPK inactivation, by AMPKα1 shRNA, knockout, or dominant-negative mutation (T172A), attenuated Lnc-THOR shRNA-induced A172 glioma cell apoptosis. Moreover, CRISPR/Cas9-induced IGF2BP1 knockout activated MAGEA6-AMPK signaling as well, causing A172 glioma cell apoptosis. Significantly, Lnc-THOR shRNA was ineffective in IGF2BP1 KO A172 cells. In vivo, Lnc-THOR silencing or knockout potently inhibited subcutaneous A172 xenograft tumor growth in mice. MAGEA6 downregulation and AMPK activation were detected in Lnc-THOR-silenced/-KO A172 tumor tissues. Taken together, Lnc-THOR depletion inhibits human glioma cell survival possibly by activating MAGEA6-AMPK signaling.

Tripterfordins A-O, Dihydro-β-agarofuran Sesquiterpenoids from the Leaves of Tripterygium wilfordii

Fifteen new dihydro-β-agarofuran-type sesquiterpenoids, tripterfordins A-O, were obtained from the aqueous EtOH extracts of the leaves of Tripterygium wilfordii. These constituted a class of highly oxygenated tricyclic sesquiterpenoid polyesters with a cinnamoyloxy group at C-1. The assignments of their structures were conducted via extensive analyses of the spectroscopic data and comparison of experimental and calculated ECD data. The absolute configurations of compounds 1, 4, 9, and 10 were established via single-crystal X-ray diffraction data. Additionally, compounds 1, 4, 9, 10, and 13 exhibited pronounced inhibitory effects on nitric oxide production in RAW 264.7 murine macrophages stimulated by lipopolysaccharide with IC₅₀ values ranging from 11.9 to 31.0 μM.

Ninjurin 2 overexpression promotes human colorectal cancer cell growth in vitro and in vivo

Ninjurin 2 (NINJ2) is a novel adhesion molecule. Its expression and potential function in human colorectal cancer (CRC) cells are studied. We show that NINJ2 is overexpressed in established (HT-29) and primary CRC cells and in human colon cancer tissues. Its expression level is low in colon epithelial cells and normal colon tissues. NINJ2 shRNA or knockout (by CRSIPR/Cas9) potently inhibited human CRC cell survival and proliferation, while significantly inducing cell apoptosis. Conversely, lentivirus-mediated NINJ2 overexpression promoted CRC cell proliferation. NINJ2 co-immunoprecipitated with multiple RTKs (EGFR, PDGFRα/β and FGFR) in CRC cells and human colon cancer tissues. In HT-29 cells, RTKs’ downstream signalings, Akt and Erk, were significantly inhibited by NINJ2 shRNA or knockout, but augmented following ectopic NINJ2 overexpression. In vivo, NINJ2-silenced or NINJ2-knockout CRC xenografts grew significantly slower than the control xenografts. Akt-Erk activation was largely inhibited in CRC xenografts with NINJ2 silencing or knockout. Taken together, NINJ2 overexpression promotes CRC cell growth in vitro and in vivo.

LIN28B-AS1-IGF2BP1 association is required for LPS-induced NFκB activation and pro-inflammatory responses in human macrophages and monocytes

Insulin-like growth factor 2 (IGF2) mRNA-binding protein 1 (IGF2BP1) mediates lipopolysaccharide (LPS)-induced NFκB activation and pro-inflammatory cytokines production in human macrophages. Recent studies have identified a novel IGF2BP1-binding LncRNA LIN28B-AS1. In the present study we show that LPS induced LIN28B-AS1-IGF2BP1 association in THP-1 macrophages, required for LPS-induced IGF2BP1-p65-p52 association and NFκB activation. LIN28B-AS1 silencing, by targeted shRNAs, potently inhibited LPS-induced activation of NFκB, as well as expression and productions of key pro-inflammatory cytokines, inducing IL-1β, IL-6 and TNF-α. Conversely, ectopic overexpression of LIN28B-AS1 in THP-1 macrophages potentiated NFκB activation and pro-inflammatory cytokines production by LPS. Significantly, LIN28B-AS1 shRNA was ineffective on LPS-induced pro-inflammatory responses in IGF2BP1-knockout THP-1 macrophages. In ex vivo cultured primary human peripheral blood mononuclear cells (PBMCs), LPS-induced IL-1β expression and production were attenuated by LIN28B-AS1 shRNA, but augmented with forced LIN28B-AS1 overexpression. Collectively, we show that LIN28B-AS1, binding to IGF2BP1, is required for LPS-induced NFκB activation and pro-inflammatory responses in human macrophages.

Triptonide acts as a novel antiprostate cancer agent mainly through inhibition of mTOR signaling pathway

BACKGROUND

The increasing incidence of prostate cancer (PCa) indicates an urgent need for the development of new effective drugs in PCa therapy. Triptonide has been reported to have a strong inhibition activity in cancers through screening of Chinese herbal medicine. This study aims to investigate the effects of triptonide on anti-PCa activity and its mechanisms.

METHODS

Three human advanced PCa cell lines PC3, DU145, and LNCap, and a human normal prostate epithelial cell line RWPE were treated with a range (0, 1.25, 2.5, 5, 10, 20, 40, 80, 160, and 320 nM) of triptonide concentrations for 72 hours respectively. Then, cell viability was assessed by cell counting kit-8. PCa cells were treated with different doses (0-20 nM) of triptonide for 72 hours. Cell cycle and apoptosis were assessed by flow cytometry assays. Nude mice bearing human PCa xenografts were intraperitoneally injected daily with either triptonide (10 mg/kg/d) or phosphate-buffered saline as a control for 35 days. RNA-sequencing (RNA-seq) was performed by an Illumina Hiseq Sequencing platform and confirmed by a real-time polymerase chain reaction. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes pathway analysis, and ingenuity pathway analysis were used to analyze RNA-seq results.

RESULTS

Triptonide effectively inhibits the proliferation of human PCa cells PC3, DU145, and LNCap in vitro with their IC₅₀ values as 11.961, 10.259, and 12.012 nM, respectively. Triptonide (10 mg/kg) potently inhibits the growth of PCa cell xenografts in vivo at an inhibition rate of over 97.95%. Treatment with triptonide (5 nM) significantly promotes cell apoptosis and retaining cell-cycle arrest in the G2/M phase. RNA-seq data revealed that total of 936 genes were upregulated or downregulated in triptonide treated. Moreover, the phosphorylation of mechanistic target of rapamycin (mTOR) and the downstream protein p70S6K were both inhibited, most obviously in PCa cells.

CONCLUSIONS

Our findings suggest that triptonide can efficaciously suppress PCa growth in vitro and in vivo via inhibiting the phosphorylation of mTOR and the activities of related downstream signaling pathways.

Targeting p38γ to inhibit human colorectal cancer cell progression

Colorectal cancer (CRC) is a common malignancy globally causing significant cancer-related mortality. Recent studies have proposed p38gamma (p38γ) as a novel cyclin-dependent kinase (CDK)-like kinase, promoting tumorigenesis and cancer progression. The current study evaluates p38γ expression and potential role in CRC. In HT-29 cells and primary human colon cancer cells, shRNA-induced p38γ silencing or CRISPR/Cas9-mediated p38γ knockout inhibited cell growth, proliferation, and migration, and induced significant apoptosis. Conversely, ectopic overexpression of p38γ further promoted the growth, proliferation, and migration of HT-29 cells and primary colon cancer cells. Retinoblastoma (Rb) phosphorylation and cyclins (E1/A) expression were decreased by p38γ silencing or KO, but increased with p38γ overexpression. p38γ mRNA and protein levels are significantly upregulated in human colon cancer tissues, when compared to levels in surrounding colon epithelial tissues. These results demonstrate that overexpression of p38γ can promote human CRC cell progression, and identify p38γ as a novel therapeutic target.

Strand-specific miR-28-3p and miR-28-5p have differential effects on nasopharyngeal cancer cells proliferation, apoptosis, migration and invasion

Background

MicroRNAs (miRNAs) play crucial roles in varieties of cancers, particularly in tumorigenesis, progression, and migration. Dysregulation of miR-28 was reported to occur in various types of human malignancies. In humans, two different mature miRNA sequences are excised from opposite arms of the stem-loop pre-miR-28, hsa-miR-28-3p and hsamiR-28-5p. However, the expression and distinct role of miR-28-3p and miR-28-5p in nasopharyngeal carcinoma (NPC) remain undetermined.

Methods

The expressions of miR-28-3p/-5p in human NPC tissues were tested by quantitative real-time PCR. miR-28-3p/-5p were overexpressed by mimics and silenced by inhibitors. The roles of miR-28-3p/-5p in NPC development were studied using cultured HONE-1 cells.

Results

The mRNA expression levels of miR-28-3p and -5p were significantly decreased in NPC tissues in comparison with adjacent normal tissues. Overexpression of miR-28-5p suppressed NPC cell proliferation and induced cell cycle arrest and apoptosis, while miR-28-3p promoted NPC cell migration and invasion. The miRNAs effected on different signal pathways: miR-28-5p altered expression of cyclin D1 and influenced the PI3K/AKT signaling pathway. In contrast, miR-28-3p downregulated Nm23-H1 and accelerated the process of EMT.

Conclusion

miR-28-3p and -5p were both downregulated in NPC tissues but had distinct biological effects in NPC cells. They may serve as potential prognostic markers and therapeutic targets for NPC.

Dexamethasone-induced cytotoxicity in human osteoblasts is associated with circular RNA HIPK3 downregulation

Dexamethasone (DEX) exerts potent cytotoxicity against cultured human osteoblasts. The current study examined the role of the circular RNA HIPK3 (circHIPK3) in the mechanism of cell death. We found that circHIPK3 expression was downregulated in DEX-treated human osteoblasts and circHIPK3 levels decreased in human necrotic femoral head tissues. In OB-6 osteoblastic cells and primary human osteoblasts ectopic overexpression of circHIPK3 potently suppressed DEX-induced apoptosis and programmed necrosis. Conversely, knockdown of circHIPK3by targeted siRNAs enhanced DEX-induced cytotoxicity in human osteoblasts. We further observed that microRNA-124 (miR-124), a key miRNA sponged by circHIPK3, accumulated following DEX treatment in OB-6 cells and primary osteoblasts. Confirming the role of miR-124 in DEX-induced cytotoxicity, miR-124 inhibitor attenuated cell death in human osteoblasts. Conversely, forced overexpression of miR-124 mimicked DEX-induced actions and induced cytotoxicity in human osteoblasts. We conclude that DEX-induced cytotoxicity in human osteoblasts is associated with circHIPK3 downregulation.

LncRNA THOR promotes tongue squamous cell carcinomas by stabilizing IGF2BP1 downstream targets

THOR, a highly conserved lncRNA, is potentially involved in various cancer development. However, its involvement in tongue squamous cell carcinoma (TSCC) remains unclear. The present study aims to explore the biological function and molecular mechanism of THOR in TSCC progression. The expressions of THOR and IGF2BP1 in TSCC tissues and adjacent non-cancerous tongue tissues (ANT) were examined through qRT-PCR. THOR levels were manipulated in TSCC cells to explore its function in cancer progression in vitro and in vivo, which were subsequently evaluated by CCK8, colony formation assay, flow cytometry, xenograft tumor assays. In situ hybridization, RIP and Western blot assay were performed to explore the underlying molecular mechanisms. We discovered that THOR and IGF2BP1 were dramatically upregulated in TSCC tissues. The expression of THOR is positively correlated with IGF2BP1 mRNA level. THOR mediated IGF2 expression via interacting with IGF2BP1, and affected the downstream MEK-ERK signaling pathway to regulate TSCC cells proliferation. THOR/IGF2BP1/IGF2-MEK-ERK axis regulated the proliferation of TSCC cells, implying that THOR would be a promising therapeutic target for TSCC patients.

Bioactive Ingredients in Chinese Herbal Medicines That Target Non-coding RNAs: Promising New Choices for Disease Treatment

Chinese herbal medicines (CHMs) are widely used in China and have long been a powerful method to treat diseases in Chinese people. Bioactive ingredients are the main components extracted from herbs that have therapeutic properties. Since artemisinin was discovered to inhibit malaria by Nobel laureate Youyou Tu, extracts from natural plants, particularly bioactive ingredients, have aroused increasing attention among medical researchers. The bioactive ingredients of some CHMs have been found to target various non-coding RNA molecules (ncRNAs), especially miRNAs, lncRNAs, and circRNAs, which have emerged as new treatment targets in numerous diseases. Here we review the evidence that, by regulating the expression of ncRNAs, these ingredients exert protective effects, including pro-apoptosis, anti-proliferation and anti-migration, anti-inflammation, anti-atherosclerosis, anti-infection, anti-senescence, and suppression of structural remodeling. Consequently, they have potential as treatment agents in diseases such as cancer, cardiovascular disease, nervous system disease, inflammatory bowel disease, asthma, infectious diseases, and senescence-related diseases. Although research has been relatively limited and inadequate to date, the promising choices and new alternatives offered by bioactive ingredients for the treatment of the above diseases warrant serious investigation.

Selective activation of tumor-suppressive MAPKP signaling pathway by triptonide effectively inhibits pancreatic cancer cell tumorigenicity and tumor growth

The mitogen-activated protein kinase (MAPK, 1K) family members ERK, JNK, and p38 play a divergent role in either promoting tumorigenesis or tumor-suppression. Activation of ERK and JNK promotes tumorigenesis; whereas, escalation of p38 inhibits carcinogenesis. As these three MAPK members are controlled by the common up-stream MAPK signaling proteins which consist of MAPK kinases (2K) and MAPK kinase kinases (3K), how to selectively actuate tumor-suppressive p38, not concurrently stimulate tumorigenic ERK and JNK, in cancer cells is a challenge for cancer researchers, and a new opportunity for novel anti-cancer drug discovery. Using human pancreatic cancer cells and xenograft mice as models, we found that a small molecule triptonide first discerningly activated the up-stream MAPK kinase kinase MEKK4, not the other two 3K members ASK1 and GADD45; and then selectively actuated the middle stream MAPK kinase MKK4, not the other two 2K members MKK3 and MKK6; and followed by activation of the MAPK member p38, not the other two members ERK and JNK. These data suggest that triptonide is a selective MEKK4-MKK4-p38 axis agonist. Consequently, selective activation of the MEKK4-MKK4-p38 signaling axis by triptonide activated tumor suppressor p21 and inhibited CDK3 expression, resulting in cancer cell cycle arrest at G2/M phase and marked inhibition of pancreatic cancer cell tumorigenic capability in vitro and tumor growth in xenograft mice. Our findings support the notion that selective activation of tumor-suppressive MEKK4-MKK4-p38-p21signaling pathway by triptonide is a new approach for pancreatic cancer therapy, providing a new drug candidate for development of novel anti-cancer therapeutics.

microRNA-4500 inhibits human glioma cell progression by targeting IGF2BP1

Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) overexpression promotes glioma cell progression. The aim of the current study is to silence IGF2BP1 in glioma cells by the microRNA (miRNA) strategy. The bio-informatic analyses identified that microRNA-4500 (miR-4500) putatively targets 3'-UTR (3'-untranslated region) of IGF2BP1. In A172 cells and primary human glioma cells ectopic overexpression of the wild-type miR-4500 (but not the mutant form) downregulated IGF2BP1 and its target genes (Gli1, IGF2 and c-Myc). Functional studies show that ectopic miR-4500 overexpression inhibited glioma cell growth, survival, proliferation, migration and invasion. Conversely, in A172 cells miR-4500 inhibition, by a lentiviral construct, increased expression of IGF2BP1 and its targets, promoting cell survival, proliferation and migration. Furthermore, IGF2BP1 knockout by the CRISPR/Cas9 method inhibited A172 cell progression. Significantly, miR-4500 overexpression or miR-4500 inhibition was ineffective in IGF2BP1 knockout A172 cells. At last, we show that miR-4500 levels are downregulated in human glioma tissues, correlating with IGF2BP1 upregulation. Together, we conclude that miR-4500 inhibits human glioma cell progression by targeting IGF2BP1.

LncRNA THOR increases osteosarcoma cell stemness and migration by enhancing SOX9 mRNA stability

Although the long non-coding RNA THOR has been reported to promote cancer stem cell expansion in liver cancer and gastric cancer, its effects on osteosarcoma (OS) cells remain unclear. Here, we investigated the roles of THOR in the stemness and migration of OS cells. We report that the level of THOR is remarkably upregulated in OS cell spheroids compared to that in OS adherent cells. THOR overexpression increased spheroid formation ability and aldehyde dehydrogenase 1 (ALDH1) activity in OS adherent cells, and the opposite effect was observed in spheroids with THOR knockdown. Additionally, the spheroids formed by OS adherent cells exhibited a stronger migration ability, which was attenuated by THOR knockdown, and THOR overexpression increased OS cell migration. Mechanistically, mRNA stability, luciferase reporter, and RNA-RNA in vitro interaction assays indicated that THOR can directly bind to the middle region of the SOX9 3'-untranslated region (UTR), and enhances its mRNA stability, thereby increasing its expression. Notably, SOX9 knockdown reduced the ability of THOR overexpression to promote the stemness of OS cells. These findings indicate that the lncRNA THOR can promote the stemness and migration of OS cells by directly binding to the middle region of SOX9 3'UTR, thereby enhancing SOX9 mRNA stability and increasing its expression; thus, we provide information that may be of use in identifying potential targets for OS treatment.

Epigallocatechin-3-gallate inhibits the growth and increases the apoptosis of human thyroid carcinoma cells through suppression of EGFR/RAS/RAF/MEK/ERK signaling pathway

Background

Thyroid cancer is the most common type of endocrine malignancy and the incidence rate is rapidly increasing worldwide. Epigallocatechin-3-gallate (EGCG) could suppress cancer growth and induce apoptosis in many types of cancer cells. However, the mechanism of action of EGCG on the growth of human thyroid carcinoma cells has not been fully illuminated.

Methods

Cell proliferation and viability were detected by EdU and MTS assays. Cell cycle distribution was measured by flow cytometry. Migration and invasion were evaluated by scratch and transwell assays. Apoptotic levels were detected by TUNEL staining and western blotting. The protein levels of EGFR/RAS/RAF/MEK/ERK signaling pathway were detected by western blotting. The in vivo results were determined by tumor xenografts in nude mice. The in vivo proliferation, tumor microvessel density, and apoptosis were detected by immunohistochemistry.

Results

EGCG inhibited the proliferation, viability, and cell cycle progression in human thyroid carcinoma cells. EGCG decreased the migration and invasion, but increased the apoptosis of human thyroid carcinoma cells. EGCG reduced the protein levels of phospho (p)-epidermal growth factor receptor (EGFR), H-RAS, p-RAF, p-MEK1/2, and p-extracellular signal-regulated protein kinase 1/2 (ERK1/2) in human thyroid carcinoma cells. EGCG inhibited the growth of human thyroid carcinoma xenografts by inducing apoptosis and down-regulating angiogenesis.

Conclusions

EGCG could reduce the growth and increase the apoptosis of human thyroid carcinoma cells through suppressing the EGFR/RAS/RAF/MEK/ERK signaling pathway. EGCG can be developed as an effective therapeutic agent for the treatment of thyroid cancer.