A large proportion of breast cancer patients are resistant to radiotherapy, which is a mainstay treatment for this malignancy, but the mechanisms of radioresistance remain unclear.
Methods and materials
To evaluate the role of miRNAs in radioresistance, we established two radioresistant breast cancer cell lines MCF-7R and T-47DR derived from parental MCF-7 and T-47D. Moreover, miRNA microarray, quantitative RT-PCR analysis, luciferase reporter assay and western blotting were used.
Results
We found that miR-668 was most abundantly expressed in radioresistant cells MCF-7R and T-47DR. miR-668 knockdown reversed radioresistance of MCF-7R and T-47DR, miR-668 overexpression enhanced radioresistance of MCF-7 and T-47D cells. Mechanically, bioinformatics analysis combined with experimental analysis demonstrated IκBα, a tumor-suppressor as well as an NF-κB inhibitor, was a direct target of miR-668. Further, miR-668 overexpression inhibited IκBα expression, activated NF-κB, thus, increased radioresistance of MCF-7 and T-47D cells. Conversely, miR-668 knockdown restored IκBα expression, suppressed NF-κB, increased radiosensitivity of MCF-7R and T-47DR cells.
Conclusion
Our findings suggest miR-668 is involved in the radioresistance of breast cancer cells and miR-668-IκBα-NF-κB axis may be a novel candidate for developing rational therapeutic strategies for human breast cancer treatment.
Inflammation plays a pivotal role in the process of carcinogenesis and phytochemicals have anti-inflammatory properties gaining more importance in cancer chemoprevention. The present study aimed to investigate the anti-inflammatory effect of allyl isothiocyanate (AITC) on 7,12-dimethylbenz(a)anthracene (DMBA)- and N-methyl-N-nitrosourea (MNU)-induced mammary carcinogenesis in female Sprague–Dawley rats.
Methods
RT-PCR and western blot analysis showed that inflammatory markers such as NF-κB p65, TNF-α, and IL-6 were overexpressed in mammary tumor tissues. Histological analysis of tumor tissues shows abnormality in hematoxylin and eosin (H&E) staining and toluidine blue (TB) staining of mast cell content, and lipid accumulation in oil red O staining.
Results
Administration of AITC (20 mg/kg bw) to carcinogen-injected rats significantly decreased the expression of NF-κB p65, TNF-α, and IL-6 in mammary tissues. Further, molecular docking study demonstrates the binding of AITC to NF-κB p65. Remarkably, AITC treatments control the growth of cancer cells as clearly evidenced by histopathological analysis. Staining of mammary tissues for mast cells and lipids indicates that AITC treatment to carcinogen-administrated rats significantly reduced mammary tumorigenesis.
Conclusions
The result suggests that AITC has anti-inflammatory potential to prevent DMBA- and MNU-induced mammary carcinogenesis in rats.
Glioblastoma multiforme (GBM) is the most malignant of brain tumors. Acquired drug resistance is a major obstacle for successful treatment. Earlier studies reported that expression of the multiple drug resistance gene (MDR1) is regulated by YB-1 or NFκB via the JNK/c-Jun or Akt pathway. Over-expression of the Dickkopf (DKK) family member DKK3 by an adenovirus vector carrying DKK3 (Ad-DKK3) exerted anti-tumor effects and led to the activation of the JNK/c-Jun pathway. We investigated whether Ad-DKK3 augments the anti-tumor effect of temozolomide (TMZ) via the regulation of MDR1.
Methods
GBM cells (U87MG and U251MG), primary TGB105 cells, and mice xenografted with U87MG cells were treated with Ad-DKK3 or TMZ alone or in combination.
Results
Ad-DKK3 augmentation of the anti-tumor effects of TMZ was associated with reduced MDR1 expression in both in vivo and in vitro studies. The survival of Ad-DKK3-treated U87MG cells was inhibited and the expression of MDR1 was reduced. This was associated with the inhibition of Akt/NFκB but not of YB-1 via the JNK/c-Jun- or Akt pathway.
Conclusions
Our results suggest that Ad-DKK3 regulates the expression of MDR1 via Akt/NFκB pathways and that it augments the anti-tumor effects of TMZ in GBM cells.
S100A4 is a small Ca2+-binding protein of the S100 family with metastasis-promoting properties. Recently, secreted S100A4 protein has been shown to possess a number of functions, including induction of angiogenesis, stimulation of cell motility and neurite extension.
Methods
Cell cultures from two human osteosarcoma cell lines, OHS and its anti-S100A4 ribozyme transfected counterpart II-11b, was treated with IFN-γ and recombinant S100A4 in order to study the sensitizing effects of extracellular S100A4 on IFN-γ mediated apoptosis. Induction of apoptosis was demonstrated by DNA fragmentation, cleavage of poly (ADP-ribose) polymerase and Lamin B.
Results
In the present work, we found that the S100A4-expressing human osteosarcoma cell line OHS was more sensitive to IFN-γ-mediated apoptosis than the II-11b cells. S100A4 protein was detected in conditioned medium from OHS cells, but not from II-11b cells, and addition of recombinant S100A4 to the cell medium sensitized II-11b cells to apoptosis induced by IFN-γ. The S100A4/IFN-γ-mediated induction of apoptosis was shown to be independent of caspase activation, but dependent on the formation of reactive oxygen species. Furthermore, addition of extracellular S100A4 was demonstrated to activate nuclear factor-κB (NF-κB).
Conclusion
In conclusion, we have shown that S100A4 sensitizes osteosarcoma cells to IFN-γ-mediated induction of apoptosis. Additionally, extracellular S100A4 activates NF-κB, but whether these events are causally related remains unknown.
Epidermal growth factor receptor (EGFR) is often overexpressed in triple-negative breast cancer (TNBC). However, clinical studies have shown that therapies against EGFR are not effective in patients with TNBC. Recently, it has been reported that arginine 198/200 in EGFR extracellular domain is methylated by PRMT1 and that the methylation confers resistance to EGFR monoclonal antibody cetuximab in colorectal cancer cells. To explore a potential mechanism underlying intrinsic resistance to anti-EGFR therapy in TNBC, we investigated the role of PRMT1 in EGFR methylation and signaling in MDA-MB-468 (468) TNBC cells.
Methods
We knocked down PRMT1 in 468 cells by shRNA, and subjected the cell lysates to Western blot analysis to examine EGFR activation and its downstream molecules. We also evaluated cell proliferation and sphere formation of PRMT1-knockdown cells. Finally, we examined the effects of pan-PRMT inhibitor, AMI-1, on cetuximab by colony formation and soft agar assays.
Results
EGFR methylation and activity was significantly reduced in PRMT1-knockdown cells compared to the parental cells. Knockdown of PRMT1 also reduced cell proliferation and sphere formation. Moreover, AMI-1 sensitized 468 cells to cetuximab.
Conclusion
The results indicate that PRMT1 is critical for EGFR activity in 468 cells. Our data also suggest that inhibition of PRMT1 sensitizes TNBC cells to cetuximab. Thus, inhibition of PRMT1 may be an effective therapeutic strategy to overcome intrinsic resistance to cetuximab in TNBC.
Cisplatin is commonly used in non-small-cell lung cancer (NSCLC) chemotherapy; however, chemoresistance to cisplatin remains a great clinical challenge. Octamer-binding protein 4 (OCT4) has been reported to be overexpressed in NSCLC. In this study, we aimed to investigate the potential role of OCT4 in NSCLC with chemoresistance to cisplatin.
Methods
Expressions of OCT4 was detected in NSCLC tissues and cell lines. We utilized siRNA to knock down OCT4 expression in human NSCLC cells and analyzed their phenotypic changes.
Results
We found that the difference of OCT4 expression between NSCLC and the adjacent non-tumourous tissues was statistically significant. Knockdown of OCT4 in NSCLC cells could decrease cell proliferation, and potentiate apoptosis induced by cisplatin, suggesting OCT4 may contribute to cisplatin resistance in NSCLC.
Conclusion
Our findings indicate that targeting OCT4 could improve cisplatin effect in NSCLC, confirming their role in modulating cisplatin sensitivity.
Curcumin has been suggested to possess anti-neoplastic properties. As oesophageal adenocarcinoma (OA) and Barrett’s oesophagus (BO) represent a neoplastic series, we postulated that curcumin supplementation may slow neoplastic progression at this site. Our aim was to investigate the effects of curcumin in vitro and in vivo on markers of oesophageal cancer progression.
Methods
We investigated the in vitro ability of curcumin to prevent bile acid-induced DNA damage using micronucleus assay and nuclear factor-kappaB (NF-κB) activity in the oesophageal cell lines (OE33) using real-time PCR of the extracted RNA. We also analysed NF-κB p65 activation in curcumin-pre-treated OE33 cells exposed to deoxycholic acid (DCA) using ELISA. In another pilot study, BO patients took a daily 500 mg curcumin tablet for 7 days prior to their endoscopy. In biopsies collected from these patients (n=33, 16 curcumin, 17 control), we examined NF-κB-driven gene expression (interleukin (IL)-8, inhibitor-kappaB (I-κB)) using real-time PCR of the extracted RNA from the biopsy sample. The apoptotic frequency was assessed by counting the number of apoptotic bodies in the epithelial cells from the Barrett’s tissue with and without curcumin.
Results
In vitro, curcumin (50 μM) significantly abrogated DNA damage and NF-κB activity induced by bile. Pretreating OE33 cells with curcumin (50 μM) completely abolished the ability of DCA (300 μM) to activate NF-κB. In vivo, IL-8 expression was non-significantly suppressed in the curcumin-supplemented patients compared to the squamous control tissue, whilst also showing a doubling in the apoptotic frequency compared to non-supplemented control patients.
Conclusions
Curcumin abrogated bile-driven effects in vitro. The in vivo data also suggests that curcumin supplementation had beneficial effects (increased apoptosis, potentially reduced NF-κB activity) in the Barrett’s tissues themselves, despite poor delivery of the curcumin to the oesophagus.
To asses the retinal pigment epithelium (RPE) function measured by EOG testing in patients with neurofibromatosis type 1 (NF-1). Our preliminary EOG results suggested dysfunction of the RPE in individuals with NF-1. In order to confirm our initial results we performed EOG examination on a larger group of NF-1 patients.
Patients
Studies were performed on 36 patients with clinically diagnosed NF-1 and compared to normal healthy controls.
Methods
Standard EOG recordings were performed in accordance with the International Society for Clinical Electrophysiology of Vision (ISCEV) standards.
Results
In NF-1 patients the Arden indexes of the EOG test were significantly higher primarily due to the lower values of dark troughs. Supernormal EOGs (exceeding the value of the mean + 2 SD from the control group) were present in 58% of NF-1 patients.
Conclusions
Dysfunction of the RPE is a characteristic feature of individuals with NF-1.
Mantle cell lymphoma (MCL) is an aggressive B cell lymphoma with an unfavorable clinical course. Besides deregulation of the cell cycle, B cell receptor (BCR) signaling, essential for MCL proliferation and survival, is also often deregulated due to constitutive activation of Bruton’s tyrosine kinase (BTK). The BTK inhibitor ibrutinib has been approved as a therapy for refractory MCL, and while it shows some clinical activity, patients frequently develop primary or secondary ibrutinib resistance and have very poor outcomes after relapsing following ibrutinib treatment.
Objective
To overcome ibrutinib resistance, new therapeutic approaches are needed. As checkpoint kinase 1 (Chk1) inhibitors have recently been shown to be effective as single agents in MCL, we assessed the combination of ibrutinib with Chk1 inhibitors.
Methods
We examined the activity of ibrutinib combined with the Chk1 inhibitor PF-00477736 in eight MCL cell lines and analyzed underlying cellular and molecular effects.
Results
The combination was synergistic in all tested cell lines through different mechanisms. The treatment induced apoptosis in ibrutinib-sensitive cell lines, while in ibrutinib-resistant cells the effect was mainly cytostatic and occurred at micromolar concentrations of ibrutinib.
Conclusions
The pharmacological approach of simultaneously targeting cell cycle checkpoints (by Chk1 inhibitors) and pro-survival pathways (by ibrutinib) might offer a promising new therapeutic strategy for MCL patients.
After the seeding ovarian cancer cells into the peritoneal cavity, ascitic fluid creates a microenvironment in which these cells can survive and disseminate. The exact nature of the interactions between malignant ascitic fluids and peritoneal mesothelial cells (HPMCs) in ovarian cancer progression has so far remained elusive. Here we assessed whether malignant ascitic fluids may promote the senescence of HPMCs and, by doing so, enhance the acquisition of their pro-cancerogenic phenotype.
Methods
Primary omentum-derived HPMCs, ovarian cancer-derived cell lines (A2780, OVCAR-3, SKOV-3), malignant ascitic fluids and benign ascitic fluids from non-cancerous patients were used in this study. Ovarian cancer cell proliferation, as well as HPMC proliferation and senescence, were determined using flow cytometry and β-galactosidase assays, respectively. Ovarian cancer cell migration was quantified using a Transwell assay. The concentrations of soluble agents in ascitic fluids, conditioned media and cell lysates were measured using DuoSet® Immunoassay Development kits.
Results
We found that HPMCs, when exposed to malignant ascitic fluids, exhibited decreased proliferation and increased senescence rates. The malignant ascitic fluids were found to contain elevated levels of HGF, TGF-β1 and GRO-1, of which HGF and GRO-1 were able to induce senescence in HPMCs. We also found that HPMCs subjected to malignant ascitic fluids or exogenously added HGF and GRO-1 stimulated ovarian cancer cell progression, which was manifested by an increased production of HA (adhesion), uPA (proliferation), IL-8 and MCP-1 (migration).
Conclusion
Our results indicate that malignant ascitic fluids may contribute to ovarian cancer progression by accelerating the senescence of HPMCs.
Sialyltransferase I (ST6Gal-I) is an enzyme involved in tumor metastasis that processes sialic acid precursors into their mature form, enabling them to regulate gene expression. However, the effect of ST6Gal-I on the biological behavior of cancer cells remain unclear. This study was the first to demonstrate the influence of ST6Gal-I on cisplatin sensitivity in cervical cancer cells.
Methods
Knockdown of ST6Gal-I was performed by shRNA and HeLa cells combination with cisplatin were tested.
Results
We showed that down-regulation of ST6Gal-I promoted cell apoptosis and inhibited proliferation and invasion in cervical cancer cells. Knockdown of ST6Gal-I by RNA interference increased the sensitivity of HeLa cells to cisplatin in vitro, and reduced tumor volume and suppressed subcutaneous tumor growth in response to cisplatin treatment in a xenograft mouse model in vivo.
Conclusions
The results provide new information that ST6Gal-I plays an important role in several biological or pathological processes including drug resistance in cervical cancer and may be a potential therapeutic target to improve the response to chemotherapy in cervical cancer patients.
Tumor-induced lymphangiogenesis and lymphatic metastasis are predominant during the metastasis of many types of cancers. However, the endogenous inhibitors that counterbalance the lymphangiogenesis and lymphatic metastasis of tumors have not been well evaluated. Kallistatin has been recognized as an endogenous angiogenesis inhibitor.
Methods and results
Our recent study showed for the first time that the lymphatic vessel density (LVD) was reduced in lung and stomach sections from kallistatin-overexpressing transgenic mice. Kallistatin expresses anti-lymphangiogenic activity by inhibiting the proliferation, migration, and tube formation of human lymphatic endothelial cells (hLECs). Therefore, the present study focuses on the relationships of changes in kallistatin expression with the lymphangiogenesis and lymphatic metastasis of gastric cancer and its underlying mechanisms. Our results revealed that the expression of kallistatin in cancer tissues, metastatic lymph nodes, and plasma of gastric cancer patients was significantly downregulated and that the plasma level of kallistatin was negatively associated with the phase of lymph node metastasis. Furthermore, treatment with kallistatin recombinant protein decreased LVD and lymph node metastases in the implanted gastric xenograft tumors of nude mice. Mechanically, kallistatin suppressed the lymphangiogenesis and lymphatic metastasis by downregulating VEGF-C expression and secretion through the LRP6/IKK/I?B/NF-?B signaling pathway in gastric cancer cells.
Conclusions
These findings demonstrated that kallistatin functions as an endogenous lymphangiogenesis inhibitor and has an important part in the lymphatic metastasis of gastric cancer.
