Corrigendum: miR-31-3p functions as a tumor suppressor by directly targeting GABBR2 in prostate cancer.

[This corrects the article DOI: 10.3389/fonc.2022.945057.].

Comparisons between treatment of isolated posterosuperior paralabral cysts and simultaneous treatment of cysts combined with associated shoulder pathologies: arthroscopic treatment of posterosuperior paralabral cysts.

INTRODUCTION: The purpose of this study is to report the radiologic and clinical outcomes of arthroscopic intervention for isolated posterosuperior paralabral cysts and simultaneous treatment of cysts combined with associated shoulder pathologies. MATERIALS AND METHODS: From March 2008 through December 2016, 70 cases (48 males and 22 females) operated on for symptomatic posterosuperior paralabral cysts were included. Mean age was 45 (range 18-69). These patients were classified into two groups depending on if they had accompanying lesions: Group I (isolated group, 27 patients) and Group II (concomitant group, 43 patients). Arthroscopic cyst decompression with a labral repair or posterior capsulotomy for patients without labral tear were performed. All concomitant pathologies were also operated simultaneously. Follow-up MRI were performed at postoperative 6 months and clinical outcomes were evaluated during the follow-up. RESULTS: Arthroscopic all intra-articular cyst decompression and labral repair was performed on 67 patients. In three patients, posterior capsulotomy without labral repair was performed for cyst removal. For 43 patients with concomitant lesions, 31 rotator cuff repairs, three SLAP repairs along with biceps tenodesis, two distal clavicle resections due to A-C joint arthritis, one calcific deposit removal, four Bankart repairs, and two acromioplasties were performed. The follow-up MRI showed complete cyst resorption except for two patients. The mean VAS, ASES, UCLA, SST and CS scores significantly improved at the last follow-up. Although both groups showed significantly improved range of motion after the surgery, improvement of ROM in Group II lagged at early periods of the rehabilitation. CONCLUSIONS: Arthroscopic labral repair with all intra-articular cysts decompression or simple posterior capsulotomy were both effective treatment modalities. If paralabral cysts were associated with other shoulder lesions, simultaneous treatment of combined lesions could be performed for the improved clinical outcomes at final follow-up with expected lag in the early rehabilitation period. LEVEL OF EVIDENCE: Level III, Retrospective Comparative Trial, Treatment Study.

Trans-tendon Suture Bridge Rotator Cuff Repair With Biceps Tendon Augmentation for Retorn High-Grade Partial Articular Supraspinatus Tendon Avulsion (PASTA) Lesions.

Revision repair of retorn partial articular supraspinatus tendon avulsion (PASTA) lesion is difficult for poor tendon quality without tear completion and repair. Trans-tendon suture bridge repair with biceps tendon augmentation can preserve the intact bursal side cuff attachment and has shown satisfactory clinical outcomes. Moreover, trans-tendon suture bridge rotator cuff repair technique, along with biceps tendon augmentation, reinforces high-grade PASTA lesions by moving the tenotomized biceps tendon into the torn articular side cuff defect with added advantage of blood supply through the tenotomized biceps tendon graft. Retear after trans-tendon repair of high-grade PASTA lesions was rare, and its poor tendon quality cause the revision repair to be too difficult. Without tear completion and rotator cuff repair, this arthroscopic trans-tendon suture bridge rotator cuff repair with biceps tendon augmentation is a reliable procedure that could be expected to produce improved short-term functional and radiologic outcomes, along with improved tendon quality of repaired tendon.

miR-31-3p functions as a tumor suppressor by directly targeting GABBR2 in prostate cancer.

MicroRNAs are key regulators of gene expression in tumorigenesis. In this study, we investigated the tumor-suppressive function of miR-31-3p. Analysis of the Gene Expression Omnibus database revealed that the expression of miR-31-3p in prostate cancer tissues is lower than that in adjacent normal tissues from patients with prostate cancer. Moreover, miR-31-3p induces apoptosis in DU145, PC-3, and LNCap prostate cancer cells, while those transfected with miR-31-3p exhibit significantly decreased cell proliferation, migration, invasiveness, and tumor sphere-forming ability, as determined using the cell counting kit-8, transwell, and sphere-forming assays. Further analysis revealed that GABBR2 is a direct target of miR-31-3p. Within a DU145 xenograft murine model, intratumoral injection of a miR-31-3p mimic suppresses tumor growth. Taken together, the findings of this study suggest that miR-31-3p performs a novel tumor-suppressive function in prostate cancer and may represent a novel target for anti-prostate cancer miRNA therapeutics.

Valproic acid protects intestinal organoids against radiation via NOTCH signaling.

Radiotherapy is a leading treatment for various types of cancer. However, exposure to high-dose ionizing radiation causes acute gastrointestinal injury and gastrointestinal syndrome. This has significant implications for human health, and therefore, radioprotection is a major area of research. Radiation induces the loss of intestinal stem cells; hence, the protection of stem cells expressing LGR5 (a marker of intestinal epithelial stem cells) is a key strategy for the prevention of radiation-induced injury. In this study, we identified valproic acid (VPA) as a potent radioprotector using an intestinal organoid culture system. VPA treatment increased the number of LGR5+ stem cells and organoid regeneration after irradiation. N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT, an inhibitor of NOTCH signaling) blocked the radioprotective effects of VPA, indicating that NOTCH signaling is a likely mechanism underlying the observed effects of VPA. In addition, VPA acted as a radiosensitizer via the inhibition of histone deacetylase (HDAC) in a colorectal cancer organoid. These results demonstrate that VPA exerts strong protective effects on LGR5+ stem cells via NOTCH signaling and that the inhibition of NOTCH signaling reduces these protective effects, providing a basis for the improved management of radiation injury.

Suture anchor fixation of comminuted inferior pole patella fracture-novel technique: suture bridge anchor fixation technique.

PURPOSE: Comminuted inferior pole fractures of the patella are notorious fractures where it is difficult to obtain rigid internal fixation by conventional tension band wiring. The purpose of this study is to evaluate the clinical and radiological outcomes of the suture bridge anchor fixation for these comminuted inferior pole fractures of the patella. METHODS: From March 2012 to December 2018, suture bridge anchor fixation for the inferior pole comminuted fracture of the patella was performed in 22 patients. There were 21 patients of inferior pole comminuted fracture and 1 patient of lower periosteal sleeve avulsion fracture. Clinical outcomes including SF-36 score, Knee injury and osteoarthritis outcome score (KOOS) and post-operative range of motion were evaluated. In all patients, suture bridge anchor fixation was performed and, tension band wiring with K wire was added for large fragment fixation in two patients. We evaluated bony union, the patellar height using Insall-Salvati ratio and its complications. RESULTS: Mean age was 46 ± 20 (15-82) years. Mean follow-up period was 25 ± 18 (11-74) months. In all patients, bony union was achieved at postoperative 4 months. At final follow-up, mean SF-36 score was 72 ± 15 (30-91) points and KOOS score was 66.7 ± 16 (43-97). The average range of motion was 134 ± 5 (125-140) degrees. As a complication, one patient developed a wound infection and subsequent osteomyelitis of inferior pole fracture fragment. Compared to the normal knee, the Insall-Salvati ratio of the injured knee averages 0.73 and this smaller ratio less than 0.8 meant patella baja. CONCLUSIONS: In the comminuted inferior pole fractures of the patella, suture bridge anchor fixation showed good bony union and satisfactory clinical outcomes at the short-term follow-up and could be a satisfactory alternative treatment option. Even though suture bridge anchor fixation in these fractures caused decreased Insall-Salvati ratio (patella height), any patellofemoral pain and limited range of motion was not developed. LEVEL OF EVIDENCE: Level IV.

Butyrate enhances the efficacy of radiotherapy via FOXO3A in colorectal cancer patient­derived organoids.

Enhancing the radioresponsiveness of colorectal cancer (CRC) is essential for local control and prognosis. However, consequent damage to surrounding healthy cells can lead to treatment failure. We hypothesized that short­chain fatty acids (SCFAs) could act as radiosensitizers for cancer cells, allowing the administration of a lower and safer dose of radiation. To test this hypothesis, the responses of three­dimensional­cultured organoids, derived from CRC patients, to radiotherapy, as well as the effects of combined radiotherapy with the SCFAs butyrate, propionate and acetate as candidate radiosensitizers, were evaluated via reverse transcription­quantitative polymerase chain reaction, immunohistochemistry and organoid viability assay. Of the three SCFAs tested, only butyrate suppressed the proliferation of the organoids. Moreover, butyrate significantly enhanced radiation­induced cell death and enhanced treatment effects compared with administration of radiation alone. The radiation­butyrate combination reduced the proportion of Ki­67 (proliferation marker)­positive cells and decreased the number of S phase cells via FOXO3A. Meanwhile, 3/8 CRC organoids were found to be non­responsive to butyrate with lower expression levels of FOXO3A compared with the responsive cases. Notably, butyrate did not increase radiation­induced cell death and improved regeneration capacity after irradiation in normal organoids. These results suggest that butyrate could enhance the efficacy of radiotherapy while protecting the normal mucosa, thus highlighting a potential strategy for minimizing the associated toxicity of radiotherapy.

miR­5191 functions as a tumor suppressor by targeting RPS6KB1 in colorectal cancer.

MicroRNAs (miRNAs/miRs) are a class of small non­coding RNAs that play pivotal roles in cancer physiology as important epigenetic regulators of gene expression. Several miRNAs have been previously discovered that regulate the proliferation of the colorectal cancer (CRC) cell line HCT116. In the present study, one of these miRNAs, miR­5191, was characterized as a tumor suppressor in CRC cells. Transfection with miR­5191 led to a significant decrease in cell proliferation, invasiveness, tumor sphere­forming ability and tumor organoid growth, as determined via trypan blue, Transwell, sphere culture and organoid culture assays, respectively. Flow cytometric analyses revealed that miR­5191 induced the cell cycle arrest and apoptosis of CRC cells. Additionally, the expression of miR­5191 was downregulated in CRC tumor tissues compared with in normal tissues, as measured by reverse transcription­quantitative PCR analysis. Ribosomal protein S6 kinase ß1 (RPS6KB1) was identified as a direct target of miR­5191. Ectopic expression of RPS6KB1 suppressed the function of miR­5191. Intratumoral injection of miR­5191 mimic suppressed tumor growth in HCT116 xenografts. These findings suggested a novel tumor­suppressive function for miR­5191 in CRC, and its potential applicability for the development of anticancer miRNA therapeutics.

miR-550a-3-5p acts as a tumor suppressor and reverses BRAF inhibitor resistance through the direct targeting of YAP.

Although evidence has emerged to suggest that YAP overexpression is a crucial factor for tumor progression and resistance to targeted drugs in multiple cancers, the miRNA-mediated YAP regulation is still unclear. Here we show that the novel miR-550a-3-5p acts as a tumor suppressor and reverses BRAF inhibitor resistance through the direct targeting of YAP. Our data showed that the miR-550a-3-5p suppressed cell proliferation, metastasis, and tumor sphere formation through the direct inhibition of YAP and its oncogenic pathway in various cancer cell types. In addition, we showed that the YAP signature was associated with poor survival of colon cancer and identified an inverse correlation between miR-550a-3-5p and YAP in colon cancer tissues. Interestingly, this inverse correlation was regulated in a density-dependent manner. Furthermore, high levels of miR-550a-3-5p were associated with a good prognosis of esophageal cancer, which was suggestive of the clinical relevance of miR-550a-3-5p-mediated YAP regulation in multiple cancers. Importantly, we demonstrated that miR-550a-3-5p treatment sensitized vemurafenib-resistant colon and melanoma cells through YAP inhibition with reduced AKT activity. Moreover, the tumor-suppressive activity of miR-550a-3-5p and its sensitization effect for vemurafenib resistance were also observed in tumor xenograft models. Collectively, our data suggest that miR-550a-3-5p acts as a tumor suppressor through the targeting of oncogenic YAP and may be a new therapeutic tool for YAP-mediated BRAF inhibitor resistance in BRAF-mutant cancer cells.

IL-4, a direct target of miR-340/429, is involved in radiation-induced aggressive tumor behavior in human carcinoma cells.

Radiotherapy induces the production of cytokines, thereby increasing aggressive tumor behavior. This radiation effect results in the failure of radiotherapy and increases the mortality rate in patients. We found that interleukin-4 (IL-4) and IL-4Rα (IL-4 receptor) are highly expressed in various human cancer cells subsequent to radiation treatment. In addition, IL-4 is highly overexpressed in metastatic carcinoma tissues compared with infiltrating carcinoma tissues. High expression of IL-4 in patients with cancer is strongly correlated with poor survival. The results of this study suggest that radiation-induced IL-4 contributes to tumor progression and metastasis. Radiation-induced IL-4 was associated with tumorigenicity and metastasis. IL-4 expression was downregulated by miR-340 and miR-429, which were decreased by ionizing radiation (IR). Radiation-regulated miR-340/429-IL4 signaling increased tumorigenesis and metastasis by inducing the production of Sox2, Vimentin, VEGF, Ang2, and MMP-2/9 via activating JAK, JNK, ß-catenin, and Stat6 in vitro and in vivo. Our study presents a conceptual advance in our understanding of the modification of tumor microenvironment by radiation and suggests that combining radiotherapy with genetic therapy to inhibit IL-4 may be a promising strategy for preventing post-radiation recurrence and metastasis in patients.

Novel miR-5582-5p functions as a tumor suppressor by inducing apoptosis and cell cycle arrest in cancer cells through direct targeting of GAB1, SHC1, and CDK2.

MicroRNAs (miRNAs) play pivotal roles in tumorigenesis as either tumor suppressors or oncogenes. In the present study, we discovered and demonstrated the tumor suppressive function of a novel miRNA miR-5582-5p. miR-5582-5p induced apoptosis and cell cycle arrest in cancer cells, but not in normal cells. GAB1, SHC1, and CDK2 were identified as direct targets of miR-5582-5p. Knockdown of GAB1/SHC1 or CDK2 phenocopied the apoptotic or cell cycle arrest-inducing function of miR-5582-5p, respectively. The expression of miR-5582-5p was lower in tumor tissues than in adjacent normal tissues of colorectal cancer patients, while the expression of the target proteins exhibited patterns opposite to that of miR-5582-5p. Intratumoral injection of a miR-5582-5p mimic or induced expression of miR-5582-5p in tumor cells suppressed tumor growth in HCT116 xenografts. Collectively, our results suggest a novel tumor suppressive function for miR-5582-5p and its potential applicability for tumor control.

miR-5003-3p promotes epithelial-mesenchymal transition in breast cancer cells through Snail stabilization and direct targeting of E-cadherin.

One of the initial steps in metastatic dissemination is the epithelial-mesenchymal transition (EMT). Along this line, microRNAs (miRNAs) have been shown to function as important regulators of tumor progression at various stages. Therefore, we performed a functional screening for EMT-regulating miRNAs and identified several candidate miRNAs. Among these, we demonstrated that miR-5003-3p induces cellular features characteristic of EMT. miR-5003-3p induced upregulation of Snail, a key EMT-promoting transcription factor and transcriptional repressor of E-cadherin, through protein stabilization. MDM2 was identified as a direct target of miR-5003-3p, the downregulation of which induced Snail stabilization. E-cadherin was also demonstrated to be a direct target of miR-5003-3p, reinforcing the EMT-promoting function of miR-5003-3p. In situ hybridization and immunohistochemical analyses using tissue microarrays revealed that miR-5003-3p expression was higher in paired metastatic breast carcinoma tissues than in primary ductal carcinoma tissues, and was inversely correlated with the expression of MDM2 and E-cadherin. Furthermore, miR-5003-3p enhanced the formation of metastatic nodules in the lungs of mice in a tail vein injection experiment. Collectively, our results suggest that miR-5003-3p functions as a metastasis activator by promoting EMT through dual regulation of Snail stability and E-cadherin, and may therefore be a potential therapeutic target in metastatic cancers.

miR-181b-3p promotes epithelial-mesenchymal transition in breast cancer cells through Snail stabilization by directly targeting YWHAG.

Epithelial-mesenchymal transition (EMT) is essential for increased invasion and metastasis during cancer progression. Among the candidate EMT-regulating microRNAs that we previously identified, miR-181b-3p was found to induce EMT in MCF7 breast cancer cells, as indicated by an EMT-characteristic morphological change, increased invasiveness, and altered expression of an EMT marker. Transfection with a miR-181b-3p inhibitor reduced the expression of mesenchymal markers and the migration and invasion of highly invasive breast cancer cells. miR-181b-3p induced the upregulation of Snail, a master EMT inducer and transcriptional repressor of E-cadherin, through protein stabilization. YWHAG was identified as a direct target of miR-181b-3p, downregulation of which induced Snail stabilization and EMT phenotypes. Ectopic expression of YWHAG abrogated the effect of miR-181b-3p, including Snail stabilization and the promotion of invasion. In situ hybridization and immunohistochemical analyses indicated that YWHAG expression was inversely correlated with the expression of miR-181b-3p and Snail in human breast cancer tissues. Furthermore, transfection with miR-181b-3p increased the frequency of metastatic nodule formation in the lungs of mice in experimental metastasis assays using MDA-MB-231 cells. Taken together, our data suggest that miR-181b-3p functions as a metastasis activator by promoting Snail-induced EMT, and may therefore be a therapeutic target in metastatic cancers.

Identification of novel therapeutic targets in the secretome of ionizing radiation­induced senescent tumor cells.

Cellular senescence is a state of irreversible growth arrest that can be triggered by multiple mechanisms, including telomere shortening, the epigenetic derepression of the INK4α/ARF locus and DNA damage. Senescence has been considered a tumor­suppressing mechanism that permanently arrests cells at risk for malignant transformation. However, accumulating evidence shows that senescent cells have deleterious effects on the tissue microenvironment. Some of these effects could be attributed to the senescence­associated secretory phenotype that has the ability to promote tumor progression. However, secreted proteins from senescent tumor cells and their effects on the tumor microenvironment due to ionizing radiation (IR) exposure have not yet been fully elucidated. In the present study, we analyzed cytokines secreted from IR­induced senescent MCF7 cells by using cytokine microarrays and confirmed by western blot analysis that increased secretion of osteoprotegerin (OPG), midkine (MDK) and apolipoprotein E3 (ApoE3) occurs in these cells. Invasive, migratory and wound­healing activities were observed in MDA­MB­231 and MCF­10A cells following treatment with recombinant human OPG, MDK and ApoE3 proteins. Additionally, tube­formation activity was assessed in OPG­, MDK­ and ApoE3­treated human umbilical vein endothelial cells (HUVECs). We found that OPG, MDK and ApoE3 affected cell motility and tube­formation activity. Since OPG markedly affected cell motility, we examined the effect of senescent conditioned media containing neutralizing OPG antibodies on migration and wound­healing activity. Our results demonstrated that IR­induced senescent tumor cells influence the tumor microenvironment by increasing the production of cytokines, such as OPG, MDK and ApoE3. Furthermore, these data suggest that OPG is likely a promising target capable of reducing the deleterious effects on the tumor microenvironment during radiation therapy.

miR-29b attenuates tumorigenicity and stemness maintenance in human glioblastoma multiforme by directly targeting BCL2L2.

Glioblastoma multiforme (GBM) is the most common malignant brain tumor and exhibits aggressive and invasive behavior. We previously identified four miRNAs-miR-29b, 494, 193a-3p, and 30e-with enhanced expression in GBM following treatment of ionizing radiation by miRNA microarray analysis. In this study, we found that only miR-29b inhibited tumor cell migration and invasion by reducing MMP-2 activity via phospho-AKT/ß-catenin signaling, and stimulated a more epithelial-like morphology. Moreover, miR-29b inhibits angiogenesis by attenuating tube formation and the expression of VEGF and Ang-2, and stemness maintenance in GBM cells, as demonstrated by decreasing neurosphere formation and cancer stem cell marker protein expression. These findings support the anti-tumor properties of miR-29b in human GBM cells. Furthermore, miR-29b expression was inversely proportional to that of BCL2L2 mRNA or protein in various cancer cell types. Interestingly, BCL2L2 mRNA is highly expressed in the mesenchymal type of GBM. To further elucidate the relationship between miR-29b and BCL2L2 in GBM, we performed co-transfection reporter assays and determined that miR-29b downregulates BCL2L2 expression by directly binding its 3'UTR. Finally, we confirmed that BCL2L2 repression is of central importance to miR-29b anti-tumor activity using functional assays to examine cell migration, invasion, angiogenesis, and stemness. From these data, we propose that miR-29b may be a useful therapeutic agent in GBM.

Ionizing radiation-inducible miR-30e promotes glioma cell invasion through EGFR stabilization by directly targeting CBL-B.

MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression at the transcriptional and post-transcriptional levels. Here we show that miR-30e, which was previously identified as an ionizing radiation-inducible miRNA, enhances cellular invasion by promoting secretion of the matrix metalloproteinase MMP-2. The enhancement of cellular invasion by miR-30e involved up-regulation of the epidermal growth factor receptor (EGFR) and subsequent activation of its downstream signaling mediators, AKT and extracellular signal-regulated kinase. EGFR up-regulation by miR-30e occurred due to stabilization of the EGFR protein. The E3 ubiquitin ligase casitas B-lineage lymphoma B (CBL-B) was down-regulated by miR-30e, and this led to increased EGFR abundance. A 3' UTR reporter assay confirmed that CBL-B is a direct target of miR-30e. Knocking down CBL-B expression phenocopied the effects of miR-30e, whereas ectopic expression of CBL-B suppressed miR-30e-induced EGFR up-regulation and invasion. Collectively, our results suggest that targeting miR-30e may limit the invasiveness induced during glioma radiotherapy.

ERp57 modulates STAT3 activity in radioresistant laryngeal cancer cells and serves as a prognostic marker for laryngeal cancer.

Although targeting radioresistant tumor cells is essential for enhancing the efficacy of radiotherapy, the signals activated in resistant tumors are still unclear. This study shows that ERp57 contributes to radioresistance of laryngeal cancer by activating STAT3. Increased ERp57 was associated with the radioresistant phenotype of laryngeal cancer cells. Interestingly, increased interaction between ERp57 and STAT3 was observed in radioresistant cells, compared to the control cells. This physical complex is required for the activation of STAT3 in the radioresistant cells. Among STAT3-regulatory genes, Mcl-1 was predominantly regulated by ERp57. Inhibition of STAT3 activity with a chemical inhibitor or siRNA-mediated depletion of Mcl-1 sensitized radioresistant cells to irradiation, suggesting that the ERp57-STAT3-Mcl-1 axis regulates radioresistance of laryngeal cancer cells. Furthermore, we observed a positive correlation between ERp57 and phosphorylated STAT3 or Mcl-1 and in vivo interactions between ERp57 and STAT3 in human laryngeal cancer. Importantly, we also found that increased ERp57-STAT3 complex was associated with poor prognosis in human laryngeal cancer, indicating the prognostic role of ERp57-STAT3 regulation. Overall, our data suggest that ERp57-STAT3 regulation functions in radioresistance of laryngeal cancer, and targeting the ERp57-STAT3 pathway might be important for enhancing the efficacy of radiotherapy in human laryngeal cancer.

3-Hydroxy-3',4'-dimethoxyflavone suppresses Bcl-w-induced invasive potentials and stemness in glioblastoma multiforme.

3-Hydroxy-3',4'-dimethoxyflavone (HDMF) is a natural chemical product that is not currently regarded as a drug. In our study, we employed glioblastoma cells and cell biology and biochemistry approaches to investigate the potential of HDMF as a natural anticancer therapy option. FACS analysis showed that treatment concentration of HDMF does not exert cytotoxicity on U251 cells. Wound-healing and invasion assays showed that HDMF dose-dependently decreased the migratory and invasive potentials of these cells, likely by indirectly inhibiting MMP-3 activity as a result of the inhibition of p38 and ERK signaling proteins - an effect of HDMF also shown by Western blotting. HDMF inhibits Bcl-w-induced neurosphere formation and the expression of glioma stem cell markers, such as Musashi, Sox-2 and c-myc. These results indicate that HDMF suppresses migratory or invasive potentials and stemness and functions as a negative agent against the aggressiveness of glioblastoma cells. We propose that HDMF has potential as anticancer drug for inhibiting the aggressiveness of glioblastoma multiforme (GBM).

ß,ß-Dimethylacrylshikonin sensitizes human colon cancer cells to ionizing radiation through the upregulation of reactive oxygen species.

Shikonin, a naphthoquinone derivative, has been shown to possess antitumor activity. In the present study, the effects of shikonin and its analog, ß,ß-dimethylacrylshikonin, were investigated as radiosensitizers on the human colon cancer cell line, HCT-116. Shikonin and, to a greater extent, its analog-induced apoptosis of HCT-116 cells further synergistically potentiated the induction of apoptosis when combined with ionizing radiation (IR) treatment. Shikonins also stimulated an increase in reactive oxygen species (ROS) production and IR-induced DNA damage. Pre-treatment with the ROS scavenger, N-acetylcysteine, suppressed the enhancement of IR-induced DNA damage and apoptosis stimulated by shikonins, indicating that shikonins exert their radiosensitizing effects through ROS upregulation. The radiosensitizing effect of shikonins was also examined in vivo using the xenograft mouse model. Consistent with the in vitro results, injection of ß,ß-dimethylacrylshikonin combined with IR treatment significantly suppressed tumor growth of the HCT-116 xenograft. Taken together, the results show that ß,ß-dimethylacrylshikonin is a promising agent for developing an improved strategy for radiotherapy against tumors.

Specificity protein 1 expression contributes to Bcl-w-induced aggressiveness in glioblastoma multiforme.

We already had reported that Bcl-w promotes invasion or migration in gastric cancer cells and glioblastoma multiforme (GBM) by activating matrix metalloproteinase-2 (MMP-2) via specificity protein 1 (Sp1) or ß-cateinin, respectively. High expression of Bcl-w also has been reported in GBM which is the most common malignant brain tumor and exhibits aggressive and invasive behavior. These reports propose that Bcl-w-induced signaling is strongly associated with aggressive characteristic of GBM. We demonstrated that Sp1 protein or mRNA expression is induced by Bcl-w using Western blotting or RT-PCR, respectively, and markedly elevated in high-grade glioma specimens compared with low-grade glioma tissues using tissue array. However, relationship between Bcl-w-related signaling and aggressive characteristic of GBM is poorly characterized. This study suggested that Bcl-w-induced Sp1 activation promoted expression of glioma stem-like cell markers, such as Musashi, Nanog, Oct4 and sox-2, as well as neurosphere formation and invasiveness, using western blotting, neurosphere formation assay, or invasion assay, culminating in their aggressive behavior. Therefore, Bcl-w-induced Sp1 activation is proposed as a putative marker for aggressiveness of GBM.