Sirtuin2 correlates with lymph node metastasis, increased FIGO stage, worse overall survival, and reduced chemosensitivity to cisplatin and paclitaxel in endometrial cancer

BACKGROUND

This study aimed to investigate the correlation of sirtuin2 (SIRT2) with clinical characteristics, prognosis in endometrial cancer (EC) patients, and its effect on chemosensitivity in EC cell lines.

METHODS

A total of 137 EC patients who underwent surgical resection were retrospectively enrolled. SIRT2 expression in tumor tissues (n = 137) and adjacent tissues (n = 61) was detected by immunohistochemistry (IHC) staining and evaluated by a semiquantitative scoring method. EC patients' clinical characteristics and survival data were collected. Besides, SIRT2 was modulated by plasmid transfection in EC cells, then their chemosensitivity to cisplatin and paclitaxel was evaluated.

RESULTS

SIRT2 was increased in tumor tissues compared with adjacent tissues (reflected by both IHC score and high-expression ratio, both P < 0.001). Meanwhile, tumor SIRT2 was positively correlated with lymph node metastasis (P = 0.037) and the International Federation of Gynecology and Obstetrics (FIGO) stage (P = 0.044), but not other clinical characteristics. Moreover, tumor SIRT2 high expression was correlated with worse overall survival (OS) (P = 0.023), while it could not independently predict OS (P = 0.090, hazard ratio = 2.782). Besides, both mRNA and protein levels of SIRT2 were increased in Ishikawa (P = 0.035) and KLE (P < 0.001) cells compared with human endometrial epithelial cells. SIRT2 overexpression decreased chemosensitivity to cisplatin and paclitaxel in Ishikawa cells, while SIRT2 knockdown increased chemosensitivity to cisplatin and paclitaxel in KLE cells (all P < 0.05).

CONCLUSION

SIRT2 correlates with lymph node metastasis, increased FIGO stage, worse OS, and reduced chemosensitivity to cisplatin and paclitaxel in EC.

Differential functions of TLE1 and TLE3 depending on a specific phosphorylation site

Mammalian Transducin-like enhancer of split (TLE) confer global repression of numerous target genes in conjunction with a myriad of DNA-binding repressors. These factors have a major role in the regulation of multiple signal transduction pathways. Evidence have been obtained regarding the possible role of some of these proteins in cancer. TLE3 was suggested as a marker for increased chemosensitivity from pathological studies. Here we demonstrate, using the TCGA data base, differences in expression of this gene compared to TLE1 in several cancers. In-vitro transduction of a retrovirus encoding TLE3 to A549 lung cancer cells increased paclitaxel effectivity while TLE1 introduction to these cells decreased it. While TLE1 and TLE3 share ∼80% amino acid identity, we show that mutating or reconstituting an amino-terminal phosphorylation site, which is present only in TLE1 but absent from TLE3, and is evolutionary conserved, converts the activity of TLE1 to that of TLE3 like and vice versa. We repeated these results in an adipocytes differentiation system. Our results reveal how a single phosphorylation site can confer distinct qualitative or quantitative activities on highly homologous transcriptional regulators.

Knockdown of PC4 increases chemosensitivity of Oxaliplatin in triple negative breast cancer by suppressing mTOR pathway

As a multifunctional nuclear protein, the human positive cofactor 4 (PC4) is highly expressed in various tumors including breast cancer and has potential roles in cancer development and progression. However, the functional signatures and molecular mechanisms of PC4 in triple negative breast cancer (TNBC) progression and chemotherapeutic response are still unknown. In this study, we found that PC4 is significantly upregulated in TNBC cells compared with non-TNBC cells, implying its potential role in TNBC. Then, in vivo and in vitro studies revealed that knockdown of PC4 increased chemosensitivity of Oxaliplation (Oxa) in TNBC by suppressing mTOR pathway. Therefore, our findings demonstrated the signatures and molecular mechanisms of PC4 in TNBC chemotherapeutic response, and indicated that PC4 might be a promising therapeutic target for TNBC.

LINC00680 enhances hepatocellular carcinoma stemness behavior and chemoresistance by sponging miR-568 to upregulate AKT3

BACKGROUND

Hepatocellular carcinoma (HCC) has an extremely poor prognosis due to the development of chemoresistance, coupled with inherently increased stemness properties. Long non-coding RNAs (LncRNAs) are key regulators for tumor cell stemness and chemosensitivity. Currently the relevance between LINC00680 and tumor progression was still largely unknown, with only one study showing its significance in glioblastoma. The study herein was aimed at identifying the role of LINC00680 in the regulation HCC stemness and chemosensitivity.

METHODS

QRT-PCR was used to detect the expression of LINC00680, miR-568 and AKT3 in tissue specimen and cell lines. Gain- or loss-of function assays were applied to access the function of LINC00680 in HCC cells, including cell proliferation and stemness properties. HCC stemness and chemosensitivity were determined by sphere formation, cell viability and colony formation. Luciferase reporter, RNA immunoprecipitation (RIP), and RNA pull-down assays were performed to examine the interaction between LINC00680 and miR-568 as well as that between miR-568 and AKT3. A nude mouse xenograft model was established for the in vivo study.

RESULTS

We found that LINC00680 was remarkably upregulated in HCC tissues. Patients with high level of LINC00680 had poorer prognosis. LINC00680 overexpression significantly enhanced HCC cell stemness and decreased in vitro and in vivo chemosensitivity to 5-fluorouracil (5-Fu), whereas LINC00680 knockdown led to opposite results. Mechanism study revealed that LINC00680 regulated HCC stemness and chemosensitivity through sponging miR-568, thereby expediting the expression of AKT3, which further activated its downstream signaling molecules, including mTOR, elF4EBP1, and p70S6K.

CONCLUSION

LINC00680 promotes HCC stemness properties and decreases chemosensitivity through sponging miR-568 to activate AKT3, suggesting that LINC00680 might be a potentially important HCC diagnosis marker and therapeutic target.

Suppression of Nanog inhibited cell migration and increased the sensitivity of colorectal cancer cells to 5-fluorouracil

Nanog is a major transcription factor related to cellular multipotency that plays important roles in the development of tumor cells, drug resistance, migration, and stemness; indicating its great potential as a therapeutic target for various malignancies including colorectal cancer (CRC). Therefore, this study was aimed to evaluate the Nanog suppression effect using small interference RNA (siRNA) combined with 5-fluorouracil (5-FU) on CRC cells. Nanog-overexpressing SW-480 cells were transfected with Nanog si-RNA and treated with 5-FU, in combination or separately. Subsequently, it was observed that Nanog expression was significantly reduced after transfection of SW-480 cells using Nanog siRNA in mRNA and protein levels. Furthermore, Nanog knockdown significantly increased CRC cell sensitivity to 5-FU drug via modulating Bax and Bcl-2 mRNA expression. Also, Nanog knockdown and 5-FU treatment cooperatively decreased the migration and self-renewal ability of SW-480 cells by regulating the expression of relevant genes. Moreover, combination therapy led to cell cycle arrest at the sub-G1 phase in CRC cells. In conclusion, our results indicated that Nanog may play an important role in the drug sensitivity, migration, and self-renewal of CRC cells; suggesting Nanog as a promising target in combination with 5-FU for the development of new therapeutic approaches for CRC.

Downregulation of GSTM2 enhances gemcitabine chemosensitivity of pancreatic cancer in vitro and in vivo

Glutathione-S-transferases (GSTs) not only show cytoprotective role and their involvement in the development of anticancer drug resistance, but also transmit signals that control cell proliferation and apoptosis. However, the role of GST isoforms in chemotherapy resistance remains elusive in pancreatic cancer. Here, we demonstrated that gemcitabine treatment increased the GSTM2 expression in pancreatic cancer cell lines. Knockdown of GSTM2 by siRNA elevated apoptosis and decreased viability of pancreatic cancer cells treated with gemcitabine. Moreover, in vivo experiments further showed that shRNA induced GSTM2 downregulation enhanced drug sensitivity of gemcitabine in orthotopic pancreatic tumor mice. We also found that GSTM2 levels were lower in tumor tissues than in non-tumor tissues and higher GSTM2 expression was significantly associated with longer overall survival. In conclusion, our findings indicate that GSTM2 expression is essential for the survival of pancreatic cancer cells undergoing gemcitabine treatment and leads to chemo resistance. Downregulation of GSTM2 in pancreatic cancer may benefit gemcitabine treatment. GSTM2 expression in patients also shows significant correlation with overall survival. Thus, our study suggests that GSTM2 is a potential target for chemotherapy optimization and prognostic biomarker of pancreatic cancer.

Daurisoline inhibits hepatocellular carcinoma progression by restraining autophagy and promoting cispaltin-induced cell death

Hepatocellular carcinoma (HCC) is a common malignancy with high cancer-associated mortality. Suppressing autophagy has been reported to promote the efficiency of chemotherapy in HCC. Daurisoline (DAS) is a constituent of Rhizoma Menispermi, and functions as a potential autophagy inhibitor to perform different cellular events. In the present study, we found that DAS treatment up-regulated autophagosomes in HCC cells, accompanied with the increases of LC3-II and p62, demonstrating the disturbance of autophagic flux. Then, by the colocalization analysis, we identified that DAS did not repress the fusion of autophagosomes and lysosomes in HCC cells. However, Lysotracker and acridine orange (OA) staining showed that DAS could suppress lysosomal acidification, as evidenced by the decreased red fluorescence. Consistently, significant decreases in mature form of cathepsin B and cathepsin D were detected in DAS-treated HCC cells. Furthermore, DAS treatment markedly promoted the anti-cancer effects of cisplatin (cDDP) on HCC cells, as revealed by the dramatically reduced cell viability and proliferation, whereas the enhanced apoptosis. Moreover, the nude mice xenograft models with HCC confirmed that compared with cDDP alone group, DAS combined with cDDP significantly reduced tumor progression in vivo. Taken together, these findings elucidated that DAS could restrain autophagic flux, potentiating the chemosensitivity of HCC cells to cDDP treatment.

Down-regulation of ClC-3 enhances chemosensitivity of colorectal cancer cells to oxaliplatin by inhibiting autophagy

BACKGROUND

Voltage-gated chloride channel 3 (ClC-3) can regulate the chemotherapy sensitivity of ovarian cancer, cervical cancer, and lung cancer, while its effect and mechanism in oxaliplatin therapy for colorectal cancer (CRC) are still unknown.

AIM

To investigate the effect of ClC-3 on oxaliplatin sensitivity and the role of autophagy in CRC cells.

METHODS

The expression of ClC-3 and microtubule-associated protein 1 light chain 3 Ⅱ (LC3-Ⅱ) in the tissues of chemotherapy resistant and sensitive CRC was detected by immunohistochemical staining. The expression levels of ClC-3 and LC3-Ⅱ in HT-29 and HT-29/L-OHP cells were detected by Western blot. After transfection of HT-29 and HT-29/L-OHP cells with ClC-3 siRNA, the sensitivity of the cells to oxaliplatin was detected by CCK-8 assay, the autophagy was detected by Cyto-ID staining, and the expression levels of autophagy-related proteins Beclin1, LC3-Ⅰ, LC3-Ⅱ, and p62 were detected by Western blot. The HT-29 and HT-29/L-OHP cells transfected with ClC-3 siRNA were subsequently treated with the autophagy agonist rapamycin, and then the sensitivity of the cells to oxaliplatin and the expression levels of Beclin1, LC3-Ⅰ, LC3-Ⅱ, p62, and ClC-3 were detected by CCK-8 assay and Western blot, respectively.

RESULTS

LC3-Ⅱ and ClC-3 were highly expressed in tissues of chemo-resistant colorectal cancer and HT-29/L-OHP cells. After inhibition of ClC-3, the sensitivity of HT-29 cells and HT-29/L-OHP cells to oxaliplatin was both increased, and the autophagy level of the cells was decreased. Rapamycin reversed the sensitization of ClC-3 inhibition to oxaliplatin in colorectal cancer cells, but had no effect on the expression of ClC-3.

CONCLUSION

Down-regulation of ClC-3 can enhance the sensitivity of colorectal cancer cells to oxaliplatin chemotherapy by inhibiting autophagy.

FABP7 is a potential biomarker to predict response to neoadjuvant chemotherapy for breast cancer

BACKGROUND

Early prediction of response to neoadjuvant chemotherapy (NAC) is critical in choosing appropriate chemotherapeutic regimen for patients with locally advanced breast cancer. Herein, we sought to identify potential biomarkers to predict the response to neoadjuvant chemotherapy for breast cancer patients.

METHODS

Three genomic profiles acquired by microarray analysis from subjects with or without residual tumors after NAC downloaded from the GEO database were used to screen the differentially expressed genes (DEGs). An array of public databases, including ONCOMINE, cBioportal, Breast Cancer Gene Expression Miner v4.0, and the Kaplan Meir-plotter, etc., were used to evaluate the potential functions, related signaling pathway, as well as prognostic values of FABP7 in breast cancer. Anti-cancer drug sensitivity assay, real-time PCR, flow cytometry and western-blotting assays were used to investigate the function of FABP7 in breast cancer cells and examine the relevant mechanism.

RESULTS

Two differentially expressed genes, including FABP7 and ESR1, were identified to be potential indicators of response to anthracycline and taxanes for breast cancer. FABP7 was associated with better chemotherapeutic response, while ESR1 was associated with poorer chemotherapeutic effectiveness. Generally, the expression of FABP7 was significantly lower in breast cancer than normal tissue samples. FABP7 mainly high expressed in ER-negative breast tumor and might regulate cell cycle to enhance chemosensitivity. Moreover, elevated FABP7 expression increased the percentage of cells at both S and G2/M phase in MDA-MB-231-ADR cells, and decreased the percentage of cells at G0/G1 phase, as compared to control group. Western-blotting results showed that elevated FABP7 expression could increase Skp2 expression, while decrease Cdh1 and p27kip1 expression in MDA-MB-231-ADR cells. In addition, FABP7 was correlated to longer recurrence-free survival (RFS) in BC patients with ER-negative subtype of BC treated with chemotherapy.

CONCLUSION

FABP7 is a potential favorable biomarker and predicts better response to NAC in breast cancer patients. Future study on the predictive value and detail molecular mechanisms of FABP7 in contribution to chemosensitivity in breast cancer is warranted.

Silencing long non-coding RNA H19 combined with paclitaxel inhibits nasopharyngeal carcinoma progression

PURPOSE

This study aimed to study the effect of long non-coding RNA (lncRNA) H19 on proliferation, apoptosis and chemosensitivity of nasopharyngeal carcinoma (NPC) cells.

METHODS

NP69 and HNE3, C666-1, SUNE1, 6-10B and 5-8F cell lines were selected to detect the expression of lncRNA H19 via RT-qPCR. LncRNA H19 was overexpressed or silenced for exploring the regulatory effect of lncRNA H19 in cell proliferation, clone formation, apoptosis and drug resistance through CCK-8, clone formation experiment and flow cytometry respectively. The tumorigenic effect of lncRNA H19 silencing was verified by xenograft tumor in nude mice. LncRNA H19 was significantly up-regulated in NPC cells.

RESULTS

Silencing lncRNA H19 inhibited the proliferation of NPC C666-1 cells and promoted apoptosis, while overexpression of lncRNA H19 promoted the proliferation of NPC C666-1 cells and inhibited apoptosis. Knockdown of lncRNA H19 in drug-resistant cells remarkably reduced their drug resistance, and overexpression of lncRNA H19 in parental cells significantly reduced their drug sensitivity. Silencing lncRNA H19 inhibits tumor growth in vivo, and silencing lncRNA H19 combined with paclitaxel can enhance tumor inhibition in vivo.

CONCLUSIONS

In NPC cells, lncRNA H19 was up-regulated, lncRNA H19 inhibited the proliferation and chemosensitivity of NPC cells, promoted apoptosis, and silencing lncRNA H19 combined with paclitaxel could enhance tumor inhibition in vivo.

MicroRNA-mediated autophagy regulation in cancer therapy: The role in chemoresistance/chemosensitivity

Chemoresistance has doubled the effort needed to reach an effective treatment for cancer. Now, scientists should consider molecular pathways and mechanisms involved in chemoresistance to overcome cancer. Autophagy is a "self-digestion" mechanism in which potentially toxic and aged organelles and macromolecules are degraded. Increasing evidence has shown that autophagy possesses dual role in cancer cells (onco-suppressor or oncogene). So, it is vital to identify its role in cancer progression and malignancy. MicroRNAs (miRs) are epigenetic factors capable of modulation of autophagy in cancer cells. In the current review, we emphasize on the relationship between miRs and autophagy in cancer chemotherapy. Besides, we discuss upstream mediators of miR/autophagy axis in cancer chemotherapy including long non-coding RNAs, circular RNAs, Nrf2 c-Myc, and HIF-1α. At the final section, we provide a discussion about how anti-tumor compounds affect miR/autophagy axis in ensuring chemosensitivity. These topics are described in this review to show how autophagy inhibition/induction can lead to chemosensitivity/chemoresistance, and miRs are considered as key players in these discussions.

TIMP-2 regulates proliferation, invasion and STAT3-mediated cancer stem cell-dependent chemoresistance in ovarian cancer cells

BACKGROUND

The metzincin family of metalloproteinases and the tissue inhibitors of metalloproteinases (TIMPs) are essential proteins required for biological processes during cancer progression. This study aimed to determine the role of TIMP-2 in ovarian cancer progression and chemoresistance by reducing TIMP-2 expression in vitro in Fallopian tube secretory epithelial (FT282) and ovarian cancer (JHOS2 and OVCAR4) cell lines.

METHODS

FT282, JHOS2 and OVCAR4 cells were transiently transfected with either single or pooled TIMP-2 siRNAs. The expression of different genes after TIMP-2 knock down (T2-KD) or in response to chemotherapy was determined at the mRNA level by quantitative real time PCR (qRT-PCR) and at the protein level by immunofluorescence. Sensitivity of the cell lines in response to chemotherapy after TIMP-2 knock down was investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 5-Ethynyl-2'-deoxyuridine (EdU) assays. Cell invasion in response to TIMP-2 knockdown was determined by xCELLigence.

RESULTS

Sixty to 90 % knock down of TIMP-2 expression was confirmed in FT282, OVCAR4 and JHOS2 cell lines at the mRNA and protein levels. TIMP-2 knock down did not change the mRNA expression of TIMP-1 or TIMP-3. However, a significant downregulation of MMP-2 in T2-KD cells occurred at both the protein and activation levels, compared to Control (Cont; scrambled siRNA) and Parental cells (P, transfection reagent only). In contrast, membrane bound MT1-MMP protein levels were significantly upregulated in T2-KD compared to Cont and P cells. T2-KD cells exhibited enhanced proliferation and increased sensitivity to cisplatin and paclitaxel treatments. Enhanced invasion was observed in the T2-KD-JOSH2 and OVCAR4 cells but not in T2-KD-FT282 cells. Treatment with cisplatin or paclitaxel significantly elevated the expression of TIMP-2 in Cont cells but not in T2-KD cells, consistent with significantly elevated expression of chemoresistance and CSC markers and activation of STAT3. Furthermore, a potent inhibitor of STAT3 activation, Momelotinib, suppressed chemotherapy-induced activation of P-STAT3 in OVCAR4 cells with concomitant reductions in the expression of chemoresistance genes and CSC markers.

CONCLUSIONS

The above results suggest that TIMP-2 may have a novel role in ovarian cancer proliferation, invasion and chemoresistance.

Inhibitory effect of bound polyphenol from foxtail millet bran on miR-149 methylation increases the chemosensitivity of human colorectal cancer HCT-8/Fu cells

Nature polyphenols widely present in plants and foods are promising candidates in cancer chemotherapy. Emerging evidence has shown that plant polyphenols regulate the expression of miRNAs to exert the anti-Multidrug resistance (MDR) activity, which partly attributes to their regulation on miRNAs methylation. Our previous study found that bound polyphenol from foxtail millet bran (BPIS) had potential as an anti-MDR agent for colorectal cancer (CRC), but its mechanism remains unclear. The present findings demonstrated that BPIS upregulated the expression of miR-149 by reducing the methylation of its CpG islands, which subsequently induced the cell cycle arrest in G2/M phase, resulting in enhancing the chemo-sensitivity of HCT-8/Fu cells. Mechanically, BPIS and its active components (FA and p-CA) reduced miR-149 methylation by inhibiting the expression levels of DNA methyltransferases, promoting a remarkable increase of miR-149 expression. Further, the increased miR-149 induced cell cycle arrest in G₂/M phase by inhibiting the expression of Akt, Cyclin B1 and CDK1, thus increasing the chemosensitivity of HCT-8/Fu cells. Additionally, a strong inducer of DNA de-methylation (5-aza-dc) treatment markedly increased the chemosensitivity of CRC through elevating miR-149 expression, which indicates the hypermethylation of miR-149 may be the key cause of drug resistance in CRC. The study indicates that the enhanced chemosensitivity of BPIS on CRC is mainly attributed to the increase of miR-149 expression induced by methylation inhibition.

MiR-132 inhibits migration and invasion and increases chemosensitivity of cisplatin-resistant oral squamous cell carcinoma cells via targeting TGF-β1

Numerous findings have demonstrated that MicroRNAs dysregulation plays a key role in many neoplasms, including oral squamous cell carcinoma (OSCC), yet the potential mechanisms of microRNAs in chemo-resistance remain elusive. Here, we analyzed the miR-132 expression in OSCC tissues and OSCC cell lines, and explored it role and mechanisms on invasion and migration and cisplatin (CDDP)-induced cell death. The clinical tissues of 37 patients with OSCCs and paired normal tissues were collected. The miR-132 expression in OSCC tissues and cell lines were detected by reverse transcription-quantitative polymerase chain reation (RT-qPCR). The in vitro repopulation models were established to mimic the biological processes of OSCC. The results showed that miR-132 expression was significantly decreased in the OSCC tissues and CDDP resistant OSCC cell line (CAL-27/CDDP). miR-132 mimic inhibited cell proliferation, invasion, migration and enhanced the pro-apoptotic ability of CDDP. On the contrary, downregulation of miR-132 promoted proliferation, invasion, migration and conferred OSCC cell resistance to CDDP-induced apoptosis in vitro. The TGF-β1 expression in OSCC tissues and CAL-27/CDDP cells was significantly higher. miR-132 significantly inhibited the TGF-β1/Smad2/3 signals. TGF-β1 upregulation significantly promoted OSCC cell proliferation and resumed OSCC cell chemo-resistance in the miR-132 overexpressing cells, which is contrary to the function of miR-132. In summary, miR-132 acts as a tumor suppressor and exerts a substantial role in inhibiting the proliferation, invasion, and enhanced the chemosensitivity to CDDP of OSCC via regulating TGF-β1/Smad2/3 signals in vitro. These observations indicate that miR-132 may be a suitable therapeutic target for the treatment of OSCC.

FUT4siRNA augments the chemosensitivity of non-small cell lung cancer to cisplatin through activation of FOXO1-induced apoptosis

Background

Increased fucosylation is associated with the chemoresistance phenotype. Meanwhile, fucosyltransferase IV (FUT4) amounts are frequently elevated in lung cancer and may be related to increased chemoresistance.

Methods

In the present work, FUT4’s role in cisplatin-induced apoptosis was assessed in A549 and H1975 cells, respectively. To clarify whether the FUT4 gene attenuates chemosensitivity in tumor cells, we constructed FUT4siRNA and evaluated its effects on cisplatin-induced apoptosis and cell growth inhibition. Cell viability, apoptosis, migration and invasion assay were conducted to investigate cisplatin sensitivity. The activation of EGFR/AKT/FOXO1 signaling were measured by western blot. The translocation of FOXO1 was assessed by IFC using Laser Scanning Confocal Microscope.

Results

We found that FUT4 knockdown dose-dependently increased cisplatin-associated cytotoxicity. Furthermore, FUT4 silencing induced apoptosis and inhibited proliferation in A549 and H1975 cells by suppressing Akt and FOXO1 phosphorylation induced by cisplatin administration, which resulted in nuclear translocation of FOXO1.

Conclusion

These results suggested FUT4 might control chemoresistance to cisplatin in lung cancer by suppressing FOXO1-induced apoptosis.

Demethylzeylasteral inhibits cell proliferation and enhances cell chemosensitivity to 5-fluorouracil in Colorectal Cancer cells

Malignant growth and chemotherapy resistance to 5-fluorouracil (5-FU) are the obstacles to the treatment of Colorectal cancer (CRC). There is need to develop effective therapeutic option. Demethylzeylasteral benefits to immune and anti-tumor function. However, the role demethylzeylasteral played in colorectal cancer remains unclear. Here, our study confirmed that demethylzeylasteral could inhibit the cell malignant capacity, such as proliferation, migration and invasion. And we also found demethylzeylasteral could cause cell cycle arrest and apoptosis. Followed we verified that combination demethylzeylasteral with 5-FU has a better curative effect in vitro. The two drugs function synergistically in SW480 and additionally in RKO. IC50 values of 5-FU decreased when combined with demethylzeylasteral. Next, we used the network pharmacology approach to explore the the potential molecular mechanism of demethylzeylasteral. We constructed the “Colorectal - targets - Demethylzeylasteral” and protein-protein interactions (PPI) networks. And 15 hub genes were found in PPI network. Then Gene Ontology (GO) enrichment analysis showed that demethylzeylasteral may affect cell cycle, apoptosis, invasion and response to chemotherapy drugs. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated demethylzeylasteral may be involved in many cancer-related pathways. Taken together, the network pharmacology approach provided a potential mechanism of demethylzeylasteral in colorectal cells. Our study indicated that demethylzeylasteral could exert anti-tumor effects and enhance the sensitivity of the Colorectal cells to 5-FU, suggesting a promising ability to serve as an anti-cancer agent in Colorectal cancer.

The efficacy of bortezomib in human multiple myeloma cells is enhanced by combination with omega-3 fatty acids DHA and EPA: Timing is essential

BACKGROUND & AIMS

Although bortezomib as one of the first line medicines that has greatly improved the overall survival of patients with multiple myeloma (MM), undesired drug resistance is frequently observed. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have been shown to be able to enhance the efficacy of chemotherapeutic drugs in many cancer types. The aim of the present study was to further evaluate the anticancer activity of DHA and EPA in relation to bortezomib chemosensitivity in human MM cells. The potential involvement of NF-κB signaling pathway was studied.

METHODS

MM cells were treated with DHA/EPA with or without bortezomib. Cell viability was estimated by WST-1 assay. Apoptotic cells were determined through flow cytometry using annexin V and propidium iodide (PI) staining. Protein expression and phosphorylation was investigated by western blotting.

RESULTS

Cell type dependent anticancer potential of DHA and EPA was observed in the cell viability assay. DHA and EPA induced apoptosis in L363, OPM2, MM.1S and U266 cell lines through both mitochondrial and death receptor pathways. Treating MM cells with DHA and EPA significantly downregulated IκBα and upregulated phosphorylation of p65, indicating that they triggered NF-κB activation in MM cells. Treating cells with DHA or EPA prior to bortezomib enhanced the induced cell death. However, concomitant use of bortezomib in combination with either of DHA or EPA decreased the cell death induced by bortezomib, indicating that timing of coincubation is important for the effects on chemosensitivity.

CONCLUSIONS

The present study provides novel evidence for the anticancer effects of DHA and EPA, and highlights their rational utilization in combination with bortezomib to achieve improved therapeutic outcome for MM.

Combined treatment with acetazolamide and cisplatin enhances the chemosensitivity of human head and neck squamous cell carcinoma TU868 cells

AIMS

To investigate whether combination of acetazolamide and cisplatin can enhance the chemosensitivity of human head and neck squamous cell carcinoma (HNSCC) cell line TU868.

METHODS

MTT assay was performed to determine the effect of acetazolamide, cisplatin and their combination on the proliferation of TU868 cells. Then the effect of these 2 drugs on the expression of proliferation-related and apoptosis-related proteins was detected by Western blot. Moreover, the effect of acetazolamide and cisplatin on the expression of aquaporin-1 was detected by RT-qPCR. Loss-of-function assays was performed to assess whether the effect of acetazolamide and cisplatin on TU868 cells was mediated by aquaporin-1. The effect of acetazolamide and cisplatin on tumor cell growth was confirmed in mice by testing the tumor growth size.

RESULTS

Acetazolamide and cisplatin treatment displayed synergistic effects on the inhibition of TU868 cell growth compared with the drugs used alone. Moreover, the acetazolamide/cisplatin combination could decrease the level of PCNA but increase the level of p53; decrease the ratio of Bcl-2/Bax and increase the expression of caspase-3 compared with the single drug treated group. Moreover, we found that the combination also significantly inhibits aquaporin-1 expression. Loss-of-function assays suggested that the anti-tumor effect of these 2 drugs was achieved via affecting aquaporin-1. Consistent with the in vitro assays, combined treatment with acetazolamide and cisplatin significantly inhibits the tumor growth in mice compared with the single drug treated group.

CONCLUSION

These results demonstrated that combined treatment with acetazolamide and cisplatin could synergistically inhibit the malignant development of HNSCC cells.

Knockdown of RhoGDI2 represses human gastric cancer cell proliferation, invasion and drug resistance via the Rac1/Pak1/LIMK1 pathway

Gastric cancer (GC) is the fifth most common primary malignancy in humans. Rho GDP dissociation inhibitor 2 (RhoGDI2) is overexpressed in multiple cancer types, but the role of RhoGDI2 in GC has not been elucidated. This study aims to determine the level of RhoGDI2 in GC and to confirm the effect of its inhibition or overexpression on GC cell migration, invasion and chemosensitivity. RhoGDI2 level is significantly enhanced in human GC tissue samples in comparison with normal gastric epithelium and corresponding para-cancerous samples. The expression of RhoGDI2 is correlated with clinicopathological parameters and prognosis. Transfection in combination with miRNA targeting of RhoGDI2 in GC cell lines remarkably downregulates GC cell migration and invasion and reduces the mRNA levels of Rac1, Pak1 and LIMK1. The inhibition of RhoGDI2 downregulates GC cell migration and invasion by attenuating the EMT cascade via the Rac1/Pak1/LIMK1 pathway. Knockdown of RhoGDI2 is a potential therapeutic strategy for GC.

Cryptotanshinone chemosensitivity potentiation by TW-37 in human oral cancer cell lines by targeting STAT3-Mcl-1 signaling

Background

Despite being one of the leading cancer types in the world, the diagnosis of oral cancer and its suitable therapeutic options remain limited. This study aims to investigate the single and chemosensitizing effects of TW-37, a BH3 mimetic in oral cancer, on human oral cancer cell lines.

Methods

We assessed the single and chemosensitizing effects of TW-37 in vitro using trypan blue exclusion assay, Western blotting, DAPI staining, Annexin V–FITC/PI double staining, and quantitative real-time PCR. Mcl-1 overexpression models were established by transforming vector and transient transfection was performed to test for apoptosis

Results

TW-37 enhanced the cytotoxicity of human oral cancer cell lines by inducing caspase-dependent apoptosis, which correlates with the reduction of the myeloid cell leukemia-1 (Mcl-1) expression via transcriptional and post-translational regulation. The ectopic expression of Mcl-1 partially attenuated the apoptosis-inducing capacity of TW-37 in human oral cancer cell lines. Besides, TW-37 decreased the phosphorylation of signal transducer and activator of transcription 3 (STAT3) at Tyr⁷⁰⁵ and nuclear translocation in human oral cancer cell lines at the early time points. Furthermore, TW-37 potentiated chemosusceptibility of cryptotanshinone in human oral cancer cell lines by suppressing STAT3–Mcl-1 signaling compared with either TW-37 or cryptotanshinone alone, resulting in potent apoptosis.

Conclusions

This study not only unravels the single and chemosensitizing effects of TW-37 for treatment of human oral cancer but also highlights the likelihood of TW-37 as a good therapeutic strategy to enhance the prognosis of patients with oral cancer in the future.

Prediction of Efficacy of Postoperative Chemotherapy by DNA Methylation of CDO1 in Gastric Cancer

BACKGROUND

CDO1 is a presumed tumor suppressor gene in human cancers, the expression of which is silenced by promoter DNA methylation. Moreover, CDO1 harbors functionally oncogenic aspects through modification of mitochondrial membrane potential. We recently proposed that this oncogenic feature allows for the prediction of the efficacy of postoperative chemotherapy in colon cancer. The present study aims to elucidate the efficacy of prediction of success of postoperative chemotherapy in advanced gastric cancer to improve the treatment strategy of patients.

MATERIALS AND METHODS

Forced expression of CDO1 in gastric cancer cell lines was assessed using the JC-1 assay. Promoter DNA methylation was investigated in quantitative TaqMan methylation-specific polymerase chain reaction in 321 pathological stage II/III advanced gastric cancer cases treated by curative gastrectomy with or without postoperative chemotherapy.

RESULTS

(1) Forced expression of CDO1 led to increased mitochondrial membrane potential, accompanied by augmented survival in gastric cancer cells under anaerobic conditions. These results suggest that CDO1-expressing cancer cells survive more easily in anaerobic lesions which are inaccessible to anticancer drugs. (2) Intriguingly, in cases with the highest CDO1 methylation (ranging from 15% to 40%), patients with postoperative chemotherapy showed significantly better survival than those with no postoperative chemotherapy. (3) A robust prognostic difference was observed that was explained by differential recurrences of distant metastasis (P = 0.0031), followed by lymph node (P = 0.0142) and peritoneal dissemination (P = 0.0472).

CONCLUSIONS

The oncogenic aspects of CDO1 can be of use to determine patients with gastric cancer who will likely respond to treatment of invisible systemic dissemination by postoperative adjuvant chemotherapy.

miR-204/COX5A axis contributes to invasion and chemotherapy resistance in estrogen receptor-positive breast cancers

Breast cancer is the most common cancer among women worldwide, with 70% being estrogen receptor-positive (ER+). Although ER-targeted treatment is effective in treating ER + breast cancer, chemoresistance and metastasis still prevail. Outcome-predictable biomarkers can help improve patient prognosis. Through the analysis of the Array Express database, The Cancer Genome Atlas-Breast Cancer datasets, and breast tumor tissue array results, we found that cytochrome c oxidase subunit 5a (COX5A) was related to poor prognosis of ER + breast cancer. Further studies revealed that COX5A was positively associated with metastasis and chemoresistance in ER + breast cancer. In vitro experiments showed that knockdown of COX5A was accompanied by a decrease in ERα expression, cell cycle arrest, and epithelial-mesenchymal transition blockade, resulting in an inhibition of proliferation and invasion. Knockdown of COX5A enhanced the chemosensitivity of breast cancer cells by decreasing adenosine triphosphate and increasing reactive oxygen species levels. We report that miR-204 can target and inhibit the expression of COX5A, thus, reversing the functions of COX5A in ER + breast cancer cells. We found that COX5A may serve as a prognostic biomarker in ER + breast cancer.

Functional loss of TAGLN inhibits tumor growth and increases chemosensitivity of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the leading cause of tumor mortality worldwide. However, the mechanisms underlying NSCLC tumorigenesis are incompletely understood. TAGLN, also named SM22, as a member of the calponin family, is highly expressed in many types of tumors. Nevertheless, its effects on NSCLC progression remain unclear. In this study, we found that TAGLN was over-expressed in tumor tissues of NSCLC patients and cell lines. Additionally, NSCLC patients with high expression showed worse overall survival rate. Then, gene silencing results indicated that TAGLN knockdown markedly inhibited proliferation and induced apoptosis in NSCLC cells, while rescue study exhibited opposite results. Moreover, suppressing TAGLN significantly reduced migration and invasion of NSCLC cells, and its over-expression promoted the migratory and invasive activities of NSCLC cells. The in vivo studies confirmed the oncogenic roles of TAGLN in NSCLC, along with clearly elevated metastasis. Notably, these effects were abrogated in mice with TAGLN deletion. Finally, we found that TAGLN knockdown could improve the sensitivity of NSCLC cells to sorafenib (SFB) and 5-FU treatment, further suppressing the proliferation, migration and invasion of NSCLC cells. Consistently, TAGLN deletion attenuated tumor xenografts growth and metastasis of NSCLC in mouse models by enhancing the anti-cancer effects of SFB and 5-FU. Altogether, these findings demonstrated that TAGLN functioned as an oncogene as well as a chemotherapeutic regulator during NSCLC development, which suggested a potential therapeutic strategy for NSCLC treatment mainly through repressing TAGLN expression.

LncRNA HOTAIR-mediated MTHFR methylation inhibits 5-fluorouracil sensitivity in esophageal cancer cells

BACKGROUND

Esophageal cancer (EC) represents one of the most aggressive digestive neoplasms globally, with marked geographical variations in morbidity and mortality. Chemoprevention is a promising approach for cancer therapy, while acquired chemoresistance is a major obstacle impeding the success of 5-fluorouracil (5-FU)-based chemotherapy in EC, with the mechanisms underlying resistance not well-understood. In the present study, we focus on exploring the role of long non-coding RNA (lncRNA) HOTAIR in EC progression and sensitivity of EC cells to 5-FU.

METHODS

Paired cancerous and pre-cancerous tissues surgically resected from EC patients were collected in this study. Promoter methylation of the MTHFR was assessed by methylation-specific PCR. RIP and ChIP assays were adopted to examine the interaction of DNA methyltransferases (DNMTs) with lncRNA HOTAIR and MTHFR, respectively. EC cells resistant to 5-FU were induced by step-wise continuous increasing concentrations of 5-FU. The sensitivity of EC cells to 5-FU in vivo was evaluated in nude mice treated with xenografts of EC cells followed by injection with 5-FU (i.p.).

RESULTS

We found reciprocal expression patterns of lncRNA HOTAIR and MTHFR in EC tissues and human EC cells. Interference with lncRNA HOTAIR enhanced 5-FU-induced apoptosis, exhibited anti-proliferative activity, and reduced promoter methylation of the MTHFR in EC cells. Besides, overexpression of MTHFR attenuated the acquired chemoresistance induced by overexpression of lncRNA HOTAIR in EC cells. At last, enhanced chemosensitivity was observed in vivo once nude mice xenografted with lncRNA HOTAIR-depleted EC cells.

CONCLUSION

Together, our study proposes that pharmacologic targeting of lncRNA HOTAIR sensitizes EC cells to 5-FU-based chemotherapy by attenuating the promoter hypermethylation of the MTHFR in EC.

Clinicopathological characteristics, prognosis, and chemosensitivity in patients with metastatic upper tract urothelial carcinoma

PURPOSE

To investigate the clinical characteristics, chemosensitivity, and outcome of metastatic upper tract urothelial carcinoma (UTUC).

PATIENTS AND METHODS

Records of patients with metastatic UTUC since January 2005 were retrieved from a database that included clinical and survival data. Statistical analyses including survival and multivariate analyses of factors were respectively performed by the Kaplan-Meier method and Cox proportional hazard model.

RESULTS

A total of 250 consecutive UTUC cases were evaluated. There were 56 patients (22.4%) with initially diagnosed stage IV disease. The most common metastatic sites were lung (39.6%), distant lymph nodes (39.2%), bone (19.6%), liver (18.0%), and adrenal gland (7.2%), respectively, and the local recurrence rate was 10.4%. Two hundred thirteen patients received first-line chemotherapy. The overall response rate was only 28.7% and the median progression-free survival time was only 5.0 months. The overall survival time of the cohort was 18.0 months. Multivariate analyses showed that initially diagnosed stage IV disease, number of metastatic organs ≥3, no response to chemotherapy and cycles of chemotherapy ≤2 were adverse prognosticators for overall survival.

CONCLUSION

UTUC presented to be more prone to metastasize than locally recur and thought to have low chemosensitivity. Stage IV disease at initial diagnosis, number of metastatic organs, response and cycles of chemotherapy were independent prognosticators for metastatic UTUC.