SPAG5 upregulation predicts poor prognosis in cervical cancer patients and alters sensitivity to taxol treatment via the mTOR signaling pathway

Previously, we found that sperm-associated antigen 5 (SPAG5) was upregulated in pelvic lymph node metastasis–positive cervical cancer. The aim of this study is to examine the role of SPAG5 in the proliferation and tumorigenicity of cervical cancer and its clinical significance in tumor progression. In our study, SPAG5 expression in cervical cancer patients was detected using quantitative real-time polymerase chain reaction, western blotting, and immunohistochemistry; cervical cancer cell function with downregulated SPAG5 in vitro was explored using tetrazolium assay, flow cytometry, and colony formation and Transwell assays. SPAG5 was upregulated in tumor tissue compared with paired adjacent noncancerous tissues; SPAG5 upregulation in tumor tissues indicated poor disease-free survival, which was also an independent prognostic indicator for cervical cancer patients. In vitro study demonstrated that SPAG5 downregulation inhibited cell proliferation and growth significantly by G2/M arrest and induction of apoptosis, and hindered cell migration and invasion. Under SPAG5 downregulation, the sensitivity of cervical cancer cells differed according to taxol dose, which correlated with mammalian target of rapamycin (mTOR) signaling pathway activity. In general, SPAG5 upregulation relates to poor prognosis in cervical cancer patients, and SPAG5 is a regulator of mTOR activity during taxol treatment in cervical cancer.     

Role of Raf-kinase inhibitor protein in colorectal cancer and its regulation by hydroxycamptothecine

Background

Recently accumulated evidence suggests that Raf kinase inhibitor protein (RKIP) participates in regulation of many signaling pathways and plays an important role in tumorigenesis and tumor metastasis. However, studies investigating the role of RKIP in colorectal cancer have not been reported. The aim of this study was to investigate the role of RKIP on colorectal cancer cell differentiation, progression and its correlation with chemosensitivity.

Results

Immunohistochemical analysis revealed that RKIP expression was higher in non-neoplastic colorectal tissue (NCRCT) and colorectal cancer tissue (CRCT) than that in metastatic lymph node tissue (MLNT) (P <0.05). P-ERK protein expression was higher in MLNT and CRCT than that in NCRCT (P = 0.02). Immunocytochemical analysis further revealed that RKIP expression was higher in the well differentiated cell line SW1116 as compared to that in the poorly differentiated cell line LoVo. Matrigel invasive assay demonstrated that the inhibition of RKIP by short hairpin RNA (shRNA) 271 transfection significantly increased the number of migrated cells (90.67 ± 4.04 vs. 37.33 ± 2.51, P <0.05), whereas over-expression of RKIP by PEBP-1 plasmid transfection significantly suppressed the number of migrated cells (79.24 ± 5.18 vs. 154.33 ± 7.25, P <0.05). Meanwhile, down-regulation of RKIP induced an increase in the cell survival rate by inhibiting apoptosis induced by hydroxycamptothecine.

Conclusions

RKIP was also found to be associated with cell differentiation, with a higher activity in well differentiated colorectal cancer cells than in poorly differentiated ones. The upregulated expression of RKIP in colorectal cancer cells inhibited cell invasion and metastasis, while downregulation of RKIP reduced chemosensitivity by inhibiting apoptosis induced by HCPT.     

RNA-Mediated Gene Silencing of Nicotinamide N-Methyltransferase Is Associated with Decreased Tumorigenicity in Human Oral Carcinoma Cells

Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer. Despite progress in the treatment of OSCC, overall survival has not improved substantially in the last three decades. Therefore, identification of reliable biomarkers becomes essential to develop effective anti-cancer therapy. In this study, we focused on the enzyme Nicotinamide N-methyltransferase (NNMT), which plays a fundamental role in the biotransformation of many xenobiotics. Although several tumors have been associated with abnormal NNMT expression, its role in cancer cell metabolism remains largely unknown. In this report, 7 human oral cancer cell lines were examined for NNMT expression by Real-Time PCR, Western blot and HPLC-based catalytic assay. Subsequently, we evaluated the in vitro effect of shRNA-mediated silencing of NNMT on cell proliferation. In vivo tumorigenicity of oral cancer cells with stable knockdown of NNMT was assayed by using xenograft models. High expression levels of NNMT were found in PE/CA PJ-15 cells, in keeping with the results of Western blot and catalytic activity assay. PE/CA PJ-15 cell line was stably transfected with shRNA plasmids against NNMT and analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and soft agar Assays. Transfected and control cells were injected into athymic mice in order to evaluate the effect of NNMT silencing on tumor growth. NNMT downregulation resulted in decreased cell proliferation and colony formation ability on soft agar. In athymic mice, NNMT silencing induced a marked reduction in tumour volume. Our results show that the downregulation of NNMT expression in human oral carcinoma cells significantly inhibits cell growth in vitro and tumorigenicity in vivo. All these experimental data seem to suggest that NNMT plays a critical role in the proliferation and tumorigenic capacity of oral cancer cells, and its inhibition could represent a potential molecular approach to the treatment of oral carcinoma.     

MicroRNA-30e Functions as a Tumor Suppressor in Cervical Carcinoma Cells through Targeting GALNT7

Cervical cancer is the third most common cancer in women worldwide. However, the underlying mechanism of occurrence and development of cervical cancer is obscure. In this study, we observed that miR-30e was downregulated in clinical cervical cancer tissues and cervical cancer cells. Next, overexpression of miR-30e reduced the cervical cancer cell growth through MTT, colony formation, EdU, and Transwell assay in SiHa and Caski cells. Subsequently, UDP-N-acetyl-D-galactosamine: polypeptide N-acetylgalactosaminyltransferase 7 (GALNT7) was identified as a potential miR-30e target by bioinformatics analysis. Moreover, we showed that miR-30e was able to bind to the 3′UTR of GALNT7 by luciferase reporter assay. In addition, the mRNA and protein levels of GALNT7 in cervical cancer cells were downregulated by miR-30e. And we validated that downregulation of GALNT7 repressed the proliferation of SiHa and Caski cells by MTT, colony formation, and Transwell assay. We identified that the restoration of GALNT7 expression was able to counteract the effect of miR-30e on cell proliferation of cervical cancer cells. Furthermore, we found that the expression levels of GALNT7 were frequently upregulated and negatively correlative to those of miR-30e in cervical cancer tissues. In addition, we validated that restoration of GALNT7 rescued the miR-30e–suppressed growth of cervical cancer xenografts in vivo. In conclusion, the current results suggest that miR-30e may function as tumor suppressors in cervical cancer through downregulation of GALNT7. Both miR-30e and its novel target, GALNT7, may play an important role in the process of cervical cancer.     

The sphingosine kinase inhibitor SKI-V suppresses cervical cancer cell growth

Overexpression and/or overactivation of sphingosine kinase 1/2 (SphK1/2) is important for tumorigenesis and progression of cervical cancer. The current study examined the potential activity and signaling mechanisms of SKI-V, a non-lipid small molecule SphK inhibitor, against cervical cancer cells. In different primary and immortalized cervical cancer cells, SKI-V exerted significant anti-cancer activity by inhibiting cell viability, colony formation, proliferation, cell cycle progression and cell migration. Significant apoptosis activation was detected in SKI-V-treated cervical cancer cells. Significantly, SKI-V also provoked programmed necrosis cascade in cervical cancer cells, as it induced mitochondrial p53-cyclophilin-D-adenine nucleotide translocator-1 (ANT1) complexation, mitochondrial membrane potential collapse, reactive oxygen species production and the release of lactate dehydrogenase into the medium. Further, SKI-V blocked SphK activation and induced ceramide accumulation in primary cervical cancer cells, without affecting SphK1/2 expression. SKI-V-induced cytotoxicity in cervical cancer cells was largely inhibited by sphingosine-1-phosphate or the SphK1 activator K6PC-5, but was sensitized by adding the short-chain ceramide C6. Moreover, SKI-V inhibited Akt-mTOR (mammalian target of rapamycin) activation in primary cervical cancer cells, and its cytotoxicity was mitigated by a constitutively-active Akt. In vivo, daily intraperitoneal injection of SKI-V significantly inhibited subcutaneous primary cervical cancer xenograft growth in nude mice. Together, the SphK inhibitor SKI-V suppresses cervical cancer growth in vitro and in vivo.     

TCTP Is an Androgen-Regulated Gene Implicated in Prostate Cancer

TCTP has been implicated in a plethora of important cellular processes related to cell growth, cell cycle progression, malignant transformation and inhibition of apoptosis. In addition to these intracellular functions, TCTP has extracellular functions and plays an important role in immune cells. TCTP expression was previously shown to be deregulated in prostate cancer, but its function in prostate cancer cells is largely unknown. Here we show that TCTP expression is regulated by androgens in LNCaP prostate cancer cells in vitro as well as human prostate cancer xenografts in vivo. Knockdown of TCTP reduced colony formation and increased apoptosis in LNCaP cells, implicating it as an important factor for prostate cancer cell growth. Global gene expression profiling in TCTP knockdown LNCaP cells showed that several interferon regulated genes are regulated by TCTP, suggesting that it may have a role in regulating immune function in prostate cancer. In addition, recombinant TCTP treatment increased colony formation in LNCaP cells suggesting that secreted TCTP may function as a proliferative factor in prostate cancer. These results suggest that TCTP may have a role in prostate cancer development.     

Functional implications of miR-145/RCAN3 axis in the progression of cervical cancer

Cervical cancer, as the second leading cause of death in women malignant tumor, is not optimistic about survival rate and late recurrence rate. RCAN3 has been reported to function in a variety of diseases, but its relationship with cervical cancer has not been reported. This study aimed to investigate whether RCAN3 contributes to the development of cervical cancer and its mechanism. RCAN3 expression was analyzed in 306 cervical cancer tissues and 13 normal healthy tissues from TCGA and GTEX databases. Kaplan-Meier analysis and Cox regression analysis were carried out to assess the potential function of RCAN3. Subsequently, the upstream regulatory miRNA of RCAN3 was predicted by bioinformatics and confirmed using dual luciferase reporter assay. CCK-8, colony formation assay, transwell assay were used for functional analysis of miR-145/RCAN3 axis in vitro. The results showed that RCAN3 was highly expressed in cervical cancer tissues, leading to poor prognosis, and could be used as a prognostic factor for cervical cancer. MiR-145 directly targeted RCAN3, which was lowly expressed in cervical cancer tissues and cell lines, and the higher the miR-145 expression, the longer the survival time of patients. Finally, from the functional experiments results we can see that miR-145 can inhibit the proliferation, migration and invasion of cervical cancer cells, but overexpression of RCAN3 can reverse miR-145-mediated inhibition. To sum up, miR-145/RCAN3 axis may serve as a potential therapeutic target to regulate the progression of cervical cancer.     

Downregulation of RKIP is associated with poor outcome and malignant progression in gliomas

Malignant gliomas are highly infiltrative and invasive tumors, which precludes the few treatment options available. Therefore, there is an urgent need to elucidate the molecular mechanisms underlying gliomas aggressive phenotype and poor prognosis. The Raf Kinase Inhibitory protein (RKIP), besides regulating important intracellular signaling cascades, was described to be associated with progression, metastasis and prognosis in several human neoplasms. Its role in the prognosis and tumourigenesis of gliomas remains unclear. In the present study, we found that RKIP protein is absent in a low frequency (10%, 20/193) of glioma tumors. Nevertheless, the absence of RKIP expression was an independent prognostic marker in glioma. Additionally, by in vitro downregulation of RKIP, we found that RKIP inhibition induces a higher viability and migration of the cells, having no effect on cellular proliferation and angiogenesis, as assessed by in vivo CAM assay. In conclusion, this is the largest series studied so far evaluating the expression levels of this important cancer suppressor protein in glioma tumors. Our results suggest that in a subset of tumors, the absence of RKIP associates with highly malignant behavior and poor survival of patients, which may be a useful biomarker for tailored treatment of glioma patients.     

Circ-CSPP1 knockdown suppresses hepatocellular carcinoma progression through miR-493-5p releasing-mediated HMGB1 downregulation

BackgroundHepatocellular carcinoma (HCC) accounts for over 80% of primary liver cancers and leads to a high death rate. Research on circular RNAs (circRNAs) suggests that circRNAs are promising biomarkers for cancer treatment. This study aimed to explore the function of a novel circRNA (circ-CSPP1) in HCC.MethodsCirc-CSPP1 was obtained from the microarray data downloaded from the Gene Expression Omnibus (GEO) database. The expression of circ-CSPP1, miR-493-5p and high mobility group box 1 (HMGB1) was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation, colony formation ability, migration and invasion were monitored using cell counting kit-8 (CCK-8) assay, colony formation assay, wound healing assay and transwell assay, respectively. The protein levels of CyclinD1, Vimentin, matrix metallopeptidase 9 (MMP-9) and HMGB1 were detected by western blot. Xenograft models were established to investigate the function of circ-CSPP1 in vivo. The association between miR-493-5p and circ-CSPP1 or HMGB1 was predicted by the online tool starBase and ensured by dual-luciferase reporter assay.ResultsThe expression of circ-CSPP1 and HMGB1 was elevated, while the expression of miR-493-5p was declined in HCC tissues and cells. Circ-CSPP1 knockdown not only depleted HCC cell proliferation, formation, migration and invasion in vitro but also inhibited tumor growth in vivo. MiR-493-5p was a target of circ-CSPP1, and HMGB1 was a target of miR-493-5p. Rescue experiments presented that miR-493-5p deficiency reversed the effects of circ-CSPP1 knockdown, and HMGB1 overexpression reversed the effects of miR-493-5p restoration. Circ-CSPP1 sponged miR-493-5p to regulate HMGB1 expression.ConclusionKnockdown of circ-CSPP1 suppressed HCC development both in vitro and in vivo by upregulation of miR-493-5p and downregulation of HMGB1, hinting that circ-CSPP1 participated in HCC pathogenesis.     

AKT2 contributes to increase ovarian cancer cell migration and invasion through the AKT2-PKM2-STAT3/NF-κB axis

Multiple studies have shown that protein kinase Bβ (AKT2) is involved in the development and progression of ovarian cancer, however, its precise role remains unclear. Here we explored the underlying molecular mechanisms how AKT2 promotes ovarian cancer progression. We examined the effects of AKT2 in vitro in two ovarian cancer cell lines (SKOV3 and HEY), and in vivo by metastasis assay in nude mice. The migration and invasion ability of SKOV3 and HEY cells was determined by transwell assay. Overexpression and knockdown (with shRNA) experiments were carried out to unravel the underlying signaling mechanisms induced by AKT2. Overexpression of AKT2 led to increased expression of pyruvate kinase (PKM2) in ovarian cancer cells and in lung metastatic foci from nude mice. Elevated AKT2/PKM2 expression induced cell migration and invasion in vitro, as well as lung metastasis in vivo; silencing AKT2 blocked these effects. Meanwhile, PKM2 overexpression was unable to increase AKT2 expression. The expressions of p-PI3K, p-AKT2, and PKM2 were increased when stimulated by epidermal growth factor (EGF); however, these expressions were blocked when inhibited the PI3K by LY294002. STAT3 expression was elevated and NF-κB p65 nuclear translocation was activated both in vitro and in vivo when either AKT2 or PKM2 was overexpressed; and these effects were inhibited when silencing AKT2 expression. Taken together, AKT2 increases the migration and invasion of ovarian cancer cells in vitro and promotes lung metastasis in nude mice in vivo through PKM2-mediated elevation of STAT3 expression and NF-κB activation. In conclusion, we highlight a novel mechanism of the AKT2-PKM2-STAT3/NF-κB axis in the regulation of ovarian cancer progression, and our work suggested that both AKT2 and PKM2 may be potential targets for the treatment of ovarian cancer.     

Ubiquitin B in Cervical Cancer: Critical for the Maintenance of Cancer Stem-Like Cell Characters

Cervical cancer cells exhibit an increased requirement for ubiquitin-dependent protein degradation associated with an elevated metabolic turnover rate. Ubiquitin, which is a small, highly conserved protein expressed in all eukaryotic cells, can be covalently linked to certain target proteins to mark them for degradation by the ubiquitin-proteasome system. Previous studies highlight the essential role of Ubiquitin B (UbB) and UbB-dependent proteasomal protein degradation in histone deacetylase inhibitor (HDACi) -induced tumor selectivity. We hypothesized that UbB plays a critical role in the function of cervical cancer stem cells. We measured endogenous UbB levels in mammospheres in vitro by real-time PCR and Western blotting. The function of UbB in cancer stem-like cells was assessed after knockdown of UbB expression in prolonged Trichostatin A-selected HeLa cells (HeLa/TSA) by measuring in vitro cell proliferation, cell apoptosis, invasion, and chemotherapy resistance as well as by measuring in vivo growth in an orthotopic model of cervical cancer. We also assessed the cancer stem cell frequency, tumorsphere formation, and in vivo growth of human cervical cancer xenografts after UbB silencing. We found that HeLa/TSA were resistant to chemotherapy, highly expressed the UbB gene and the stem cell markers Sox2, Oct4 and Nanog. These cells also displayed induced differentiation abilities, including enhanced migration/invasion/malignancy capabilities in vitro and in vivo. Furthermore, an elevated expression of UbB was shown in the tumor samples of chemotherapy patients. Silencing of UbB inhibited tumorsphere formation, lowered the expression of stem cell markers and decreased cervical xenograft growth. Our results demonstrate that UbB was significantly increased in prolonged Trichostatin A-selected HeLa cells and it played a key role in the maintenance of cervical cancer stem-like cells.     

YAP Promotes Ovarian Cancer Cell Tumorigenesis and Is Indicative of a Poor Prognosis for Ovarian Cancer Patients

YAP is a key component of the Hippo signaling pathway and plays a critical role in the development and progression of multiple cancer types, including ovarian cancer. However, the effects of YAP on ovarian cancer development in vivo and its downstream effectors remain uncertain. In this study we found that strong YAP expression was associated with poor ovarian cancer patient survival. Specifically, we showed for the first time that high YAP expression levels were positively correlated with TEAD4 gene expression, and their co-expression was a prognostic marker for poor ovarian cancer survival. Hyperactivation of YAP by mutating its five inhibitory phosphorylation sites (YAP-5SA) increased ovarian cancer cell proliferation, resistance to chemotherapeutic drugs, cell migration, and anchorage-independent growth. In contrast, expression of a dominant negative YAP mutant reversed these phenotypes in ovarian cancer cells both in vitro and in vivo. Our results suggested that YAP caused these effects by promoting an epithelial-to-mesenchymal transition. Thus, YAP promotes ovarian cancer cell growth and tumorigenesis both in vitro and in vivo. Further, high YAP and TEAD4 expression is a prognostic marker for ovarian cancer progression and a potential target for ovarian cancer treatment.     

Effects of raf kinase inhibitor protein expression on metastasis and progression of human epithelial ovarian cancer

Loss of function of metastasis suppressor genes is an important step in the progression to a malignant tumor type. Studies in cell culture and animal models have suggested a role of Raf kinase inhibitor protein (RKIP) in suppressing the metastatic spread of prostate cancer, breast cancer, and melanoma cells. However, the function of RKIP in ovarian cancer (OVCA) has not been reported. To explore the potential role of RKIP in epithelial OVCA metastasis, we detected the expression levels of RKIP protein in tissue samples from patients with epithelial OVCA. Consequently, the expression of RKIP is reduced in the poorly differentiated OVCA than in the well-differentiated and moderately differentiated OVCA. In addition, in vitro cell invasion assay indicated that the RKIP expression was inversely associated with the invasiveness of five OVCA cell lines. Consistent with this result, the cell proliferation, anchorage-independent growth, cell adhesion, and invasion were decreased in RKIP overexpressed cells but increased in RKIP down-regulated cells. Further investigation indicated that RKIP inhibited OVCA cell proliferation by altering cell cycle progression rather than promoting apoptosis. Furthermore, the overexpression of RKIP suppressed the ability of human OVCA cells to metastasize when the tumor cells were transplanted into nude mice. Our data show the effect of RKIP on the proliferation, migration, or adhesion of OVCA cells. These results indicate that RKIP is also a metastasis suppressor gene of human epithelial OVCA.     

Apatinib,a novel tyrosine kinase inhibitor,suppresses tumor growth in cervical cancer and synergizes with Paclitaxel

Apatinib is a novel tyrosine kinase inhibitor that targets VEGFR2 signal and exhibits potent anti-tumor effects in human cancers. In this study, we aim to investigate the efficacy of Apatinib in cervical cancer. The protein expression of VEGFR2 and its relationships with clinical parameters were investigated in a panel of cervical cancer patients. In vitro, a series of experiments were performed to detect the effects of Apatinib on the proliferation, apoptosis and cell cycle in cervical cancer cells. Both the immortalized cell lines and primary cultured tissues were used to investigate the synergy between Apatinib and chemotherapeutic drugs. The in vivo effects of Apatinib were validated in a nude mouse model. Compared to that in normal cervix, VEGFR2 protein was significantly upregulated in cervical cancer tissues (P < 0.001); this was positively correlated with advanced tumor stage, lymph node metastasis, and a poor prognosis. In vitro, Apatinib markedly induced apoptosis and G1-phase arrest, suppressed cell growth, and decreased colony formation ability. We also found that primary cancer tissues with higher level of VEGFR2 were much more sensitive to Apatinib. Further, we proved that Apatinib significantly increased the sensitivity to Paclitaxel in cervical cancer cells and the mouse model. Collectively, we firstly report the anti-tumor efficacy of Apatinib in cervical cancer. Moreover, Apatinib synergized with Paclitaxel to achieve more significant suppression on tumor growth, proposing that Apatinib might be a potent drug for cervical cancer.     

LncRNA CRNDE promotes the progression and angiogenesis of pancreatic cancer via miR-451a/CDKN2D axis

BackgroundThe lncRNA colorectal neoplasia differentially expressed (lncRNA CRNDE) has been reported to play a pivotal role in various cancers. However, the expression and function of CRNDE in pancreatic cancer remain unclear. The objective of this study was to investigate the effects of CRNDE on pancreatic cancer and the underlying mechanisms.MethodsThe expression of CRNDE in pancreatic cancer tissues and cell lines was determined by RT-qPCR. Proliferation and angiogenesis were detected by MTT, colony formation, transwell and tube formation assays in vitro and in vivo. ELISA assay was used to detect the secretion of VEGFA. IHC was performed to test the expression levels of Ki67 and CD31. The binding sites between CRNDE, CDKN2D and miR-451a were predicted by bioinformatics analysis. Dual luciferase reporter and RNA immunoprecipitation assays were conducted to confirm the interaction with each other.ResultsThe results showed that CRNDE was significantly up-regulated in pancreatic cancer tissues as well as cell lines. CRNDE overexpression promoted the progression and angiogenesis of pancreatic cancer cells in vitro and in vivo. Moreover, we identified that CRNDE functioned as a sponge for miR-451a and CRNDE overexpression inhibited the expression of miR-451a. Furthermore, we confirmed that miR-451a directly interacted with CDKN2D and negatively regulated CDKN2D expression. In addition, CRNDE was found to positively regulate CDKN2D expression and mediate pancreatic cancer cell proliferation and angiogenesis through miR-451a/CDKN2D axis.ConclusionCRNDE modulates cell proliferation and angiogenesis via miR-451a/CDKN2D axis in pancreatic cancer, which provides a potential therapeutic target for pancreatic cancer treatment.     

Long non-coding RNA 657 suppresses hepatocellular carcinoma cell growth by acting as a molecular sponge of miR-106a-5p to regulate PTEN expression

Previous study has identified the aberrant expression of LINC00657, a long non-coding RNA (lncRNA), in human breast cancer. However, the expression pattern, biological function and underlying mechanism of LINC00657 in human hepatocellular carcinoma (HCC) remain obscure. The expression levels of LINC00657 in HCC tissues and cell lines were determined by quantitative real-time PCR. CCK-8 assay, cell colony formation assay, cell cycle analysis, Transwell assay were performed to determine whether LINC00657 could affect HCC progression. Luciferase reporter assay was used to assess the target of LINC00657. Expressions of the relevant proteins were analyzed by Western blot. Herein, we found that LINC00657 was downregulated in HCC tissue specimens as well as in malignant HCC cell lines. LINC00657 overexpression inhibited the proliferation, migration and invasion of HCC cells, while LINC00657 depletion promoted both cell viability and cell invasion in vitro. We also found that LINC00657 could inhibit tumor growth in vivo. Further experiments demonstrated that down-regulated LINC00657 increased the expression of miR-106a-5p. miR-106a-5p decreased the abundances of PTEN protein, while had no impact on PTEN mRNA. Moreover, we identified that both LINC00657 and PTEN mRNA were targets of miR-106a-5p by using dual-luciferase reporter assay. Our results provide the new evidence supporting the tumor-suppressive role of LINC00657 in HCC, suggesting that LINC00657 might play a role in HCC and can be a novel therapeutic target for treating HCC.     

HYAL1 and HYAL2 inhibit tumour growth in vivo but not in vitro

Background

We identified two 3p21.3 regions (LUCA and AP20) as most frequently affected in lung, breast and other carcinomas and reported their fine physical and gene maps. It is becoming increasingly clear that each of these two regions contains several TSGs. Until now TSGs which were isolated from AP20 and LUCA regions (e.g.G21/NPRL2, RASSF1A, RASSF1C, SEMA3B, SEMA3F, RBSP3) were shown to inhibit tumour cell growth both in vitro and in vivo.

Methodology/Principal Findings

The effect of expression HYAL1 and HYAL2 was studied by colony formation inhibition, growth curve and cell proliferation tests in vitro and tumour growth assay in vivo. Very modest growth inhibition was detected in vitro in U2020 lung and KRC/Y renal carcinoma cell lines. In the in vivo experiment stably transfected KRC/Y cells expressing HYAL1 or HYAL2 were inoculated into SCID mice (10 and 12 mice respectively). Tumours grew in eight mice inoculated with HYAL1. Ectopic HYAL1 was deleted in all of them. HYAL2 was inoculated into 12 mice and only four tumours were obtained. In 3 of them the gene was deleted. In one tumour it was present but not expressed. As expected for tumour suppressor genes HYAL1 and HYAL2 were down-expressed in 15 fresh lung squamous cell carcinomas (100%) and clear cell RCC tumours (60–67%).

Conclusions/Significance

The results suggest that the expression of either gene has led to inhibition of tumour growth in vivo without noticeable effect on growth in vitro. HYAL1 and HYAL2 thus differ in this aspect from other tumour suppressors like P53 or RASSF1A that inhibit growth both in vitro and in vivo. Targeting the microenvironment of cancer cells is one of the most promising venues of cancer therapeutics. As major hyaluronidases in human cells, HYAL1 and HYAL2 may control intercellular interactions and microenvironment of tumour cells providing excellent targets for cancer treatment.