Livin gene plays a role in drug resistance of colon cancer cells. Clin Biochem. 2010;43:655-660. [PMID: 20171199 DOI: 10.1016/j.clinbiochem.2010.02.004]

The pathological role of C-X-C chemokine receptor type 4 (CXCR4) in colorectal cancer (CRC) progression; special focus on molecular mechanisms and possible therapeutics

Colorectal cancer (CRC) is comprised of transformed cells and non-malignant cells including cancer-associated fibroblasts (CAF), endothelial vasculature cells, and tumor-infiltrating cells. These nonmalignant cells, as well as soluble factors (e.g., cytokines), and the extracellular matrix (ECM), form the tumor microenvironment (TME). In general, the cancer cells and their surrounding TME can crosstalk by direct cell-to-cell contact and via soluble factors, such as cytokines (e.g., chemokines). TME not only promotes cancer progression through growth-promoting cytokines but also provides resistance to chemotherapy. Understanding the mechanisms of tumor growth and progression and the roles of chemokines in CRC will likely suggest new therapeutic targets. In this line, a plethora of reports has evidenced the critical role of chemokine receptor type 4 (CXCR4)/C-X-C motif chemokine ligand 12 (CXCL12 or SDF-1) axis in CRC pathogenesis. In the current review, we take a glimpse into the role of the CXCR4/CXCL12 axis in CRC growth, metastasis, angiogenesis, drug resistance, and immune escape. Also, a summary of recent reports concerning targeting CXCR4/CXCL12 axis for CRC management and therapy has been delivered.

Novel strategies to reverse chemoresistance in colorectal cancer

Colorectal cancer (CRC) is a common gastrointestinal malignancy with high morbidity and fatality. Chemotherapy, as traditional therapy for CRC, has exerted well antitumor effect and greatly improved the survival of CRC patients. Nevertheless, chemoresistance is one of the major problems during chemotherapy for CRC and significantly limits the efficacy of the treatment and influences the prognosis of patients. To overcome chemoresistance in CRC, many strategies are being investigated. Here, we review the common and novel measures to combat the resistance, including drug repurposing (nonsteroidal anti-inflammatory drugs, metformin, dichloroacetate, enalapril, ivermectin, bazedoxifene, melatonin, and S-adenosylmethionine), gene therapy (ribozymes, RNAi, CRISPR/Cas9, epigenetic therapy, antisense oligonucleotides, and noncoding RNAs), protein inhibitor (EFGR inhibitor, S1PR2 inhibitor, and DNA methyltransferase inhibitor), natural herbal compounds (polyphenols, terpenoids, quinones, alkaloids, and sterols), new drug delivery system (nanocarriers, liposomes, exosomes, and hydrogels), and combination therapy. These common or novel strategies for the reversal of chemoresistance promise to improve the treatment of CRC.

Identification of novel hub genes associated with lymph node metastasis of head and neck squamous cell carcinoma by completive bioinformatics analysis

Background

Head and neck squamous cell carcinoma (HNSCC) is one of the most serious diseases affecting populations worldwide and lymph node metastasis is a key pathological feature of HNSCC which predicts poor survival. However, the molecular mechanisms associated with the development of lymph node metastasis in HNSCC have not been fully elucidated.

Methods

Differentially expressed genes (DEGs) were identified in two HNSCC datasets (GES6631 and GES58911). Functional annotation analysis was constructed via Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Meanwhile, the protein-protein interaction (PPI) network and module analysis using Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and Cytoscape were carried out to identify the hub genes. The expression differences, overall survival (OS), and disease-free survival (DFS) of hub genes were analyzed by Gene Expression Profiling Interactive Analysis 2 (GEPIA2) and verified by immunohistochemistry (IHC) from Human Protein Atlas (HPA). Moreover, receiver operating characteristic (ROC) curve analysis was conducted to judge whether those hub genes had good diagnostic and prognostic ability, and the web tool Tumor Immune Estimation Resource (TIMER) was used to analyze the correlation of hub genes’ expression and immune infiltration.

Results

In total, 913 DEGs including 476 upregulated and 437 downregulated genes were identified. The genes Aurora kinase A (AURKA), CyclinB1 (CCNB1), Cyclin-dependent kinase regulatory subunit 1B (CKS1B), Serpin Family H Member 1(SERPINH1), and Transforming growth factor-beta-induced protein (TGFBI) were screened out as hub genes and were associated with lymph node metastasis, showing notably abnormal expression in HNSCC samples, and the high expression of all the hub genes in HNSCC patients was related to worse overall survival.

Conclusions

The genes AURKA, CCNB1, CKS1B, SERPINH1, and TGFBI may be involved in the lymph node metastasis of HNSCC and reveal the potential to serve as molecular biomarkers in the diagnosis of HNSCC. This study may help to elucidate the molecular mechanisms of the development of lymph node metastasis and facilitate the selection of targets for the treatment and diagnosis of HNSCC.

Assessing the protective effects of cryptotanshinone on CoCl2‑induced hypoxia in RPE cells

The development of several retinal diseases is closely related to hypoxia. As a component of the Traditional Chinese medicine Salvia miltiorrhiza, the effects of cryptotanshinone (CT) on retinal cells under hypoxic conditions are not well understood. The aim of the present study was to explore how CT exerted its protective effects on retinal pigment epithelium (RPE) cells under hypoxic conditions induced by cobalt chloride (CoCl₂). The effects of CT were investigated using a Cell Counting Kit-8 assay, Annexin V-FITC/PI staining, reverse transcription-quantitative PCR and western blotting in ARPE-19 cells. CT (10 and 20 µM) reduced the CoCl₂-induced increase in vascular endothelial growth factor expression and hypoxia-inducible transcription factor-1α expression in ARPE-19 cells. Additionally, CT alleviated hypoxia-induced apoptosis by regulating Bcl-2 and Bax protein expression. CT treatment also reduced the increase in the mRNA levels of IL-6, IL-1β and TNF-α induced by CoCl₂. In summary, CT may protect RPE cells against apoptosis and inflammation in CoCl₂-induced hypoxia, and these results warrant further in vivo study into its value as a drug for treating hypoxic eye diseases.

Tumor Suppressor Protein p53 and Inhibitor of Apoptosis Proteins in Colorectal Cancer-A Promising Signaling Network for Therapeutic Interventions

Simple Summary

Tumor suppressor 53 (p53) is a multifunctional protein that regulates cell cycle, DNA repair, apoptosis and metabolic pathways. In colorectal cancer (CRC), mutations of the gene occur in 60% of patients and are associated with a more aggressive tumor phenotype and resistance to anti-cancer therapy. In addition, inhibitor of apoptosis (IAP) proteins are distinguished biomarkers overexpressed in CRC that impact on a diverse set of signaling pathways associated with the regulation of apoptosis/autophagy, cell migration, cell cycle and DNA damage response. As these mechanisms are further firmly controlled by p53, a transcriptional and post-translational regulation of IAPs by p53 is expected to occur in cancer cells. Here, we aim to review the molecular regulatory mechanisms between IAPs and p53 and discuss the therapeutic potential of targeting their interrelationship by multimodal treatment options.

Abstract

Despite recent advances in the treatment of colorectal cancer (CRC), patient’s individual response and clinical follow-up vary considerably with tumor intrinsic factors to contribute to an enhanced malignancy and therapy resistance. Among these markers, upregulation of members of the inhibitor of apoptosis protein (IAP) family effects on tumorigenesis and radiation- and chemo-resistance by multiple pathways, covering a hampered induction of apoptosis/autophagy, regulation of cell cycle progression and DNA damage response. These mechanisms are tightly controlled by the tumor suppressor p53 and thus transcriptional and post-translational regulation of IAPs by p53 is expected to occur in malignant cells. By this, cellular IAP1/2, X-linked IAP, Survivin, BRUCE and LIVIN expression/activity, as well as their intracellular localization is controlled by p53 in a direct or indirect manner via modulating a multitude of mechanisms. These cover, among others, transcriptional repression and the signal transducer and activator of transcription (STAT)3 pathway. In addition, p53 mutations contribute to deregulated IAP expression and resistance to therapy. This review aims at highlighting the mechanistic and clinical importance of IAP regulation by p53 in CRC and describing potential therapeutic strategies based on this interrelationship.

Recent developments in targeting genes and pathways by RNAi-based approaches in colorectal cancer

A wide spectrum of genetic and epigenetic variations together with environmental factors has made colorectal cancer (CRC), which involves the colon and rectum, a challenging and heterogeneous cancer. CRC cannot be effectively overcomed by common conventional therapies including surgery, chemotherapy, targeted therapy, and hormone replacement which highlights the need for a rational design of novel anticancer therapy. Accumulating evidence indicates that RNA interference (RNAi) could be an important avenue to generate great therapeutic efficacy for CRC by targeting genes that are responsible for the viability, cell cycle, proliferation, apoptosis, differentiation, metastasis, and invasion of CRC cells. In this review, we underline the documented benefits of small interfering RNAs and short hairpin RNAs to target genes and signaling pathways related to CRC tumorigenesis. We address the synergistic effects of RNAi-mediated gene knockdown and inhibitors/chemotherapy agents to increase the sensitivity of CRC cells to common therapies. Finally, this review points new delivery systems/materials for improving the cellular uptake efficiency and reducing off-target effects of RNAi.

CKS1B as Drug Resistance-Inducing Gene-A Potential Target to Improve Cancer Therapy

Cancer is a threat to human health and life. Although previously centered on chemical drug treatments, cancer treatment has entered an era of precision targeted therapy. Targeted therapy entails precise guidance, allowing the selective killing of cancer cells and thereby reducing damage to healthy tissues. Therefore, the need to explore potential targets for tumor treatment is vital. Cyclin-dependent kinase regulatory subunit 1B (CKS1B), a member of the conserved cyclin kinase subunit 1 (CKS1) protein family, plays an essential role in cell cycling. A large number of studies have shown that CKS1B is associated with the pathogenesis of many human cancers and closely related to drug resistance. Here, we describe the current understanding of the cellular functions of CKS1B and its underlying mechanisms, summarize a recent study of CKS1B as a target for cancer treatment and discuss the potential of CKS1B as a therapeutic target.

Huaier Granule Combined with Tegafur Gimeracil Oteracil Potassium Promotes Stage IIb Gastric Cancer Prognosis and Induces Gastric Cancer Cell Apoptosis by Regulating Livin

Gastric cancer is one of the most common malignancies worldwide, with high morbidity and poor survival rate. Its prognosis remains unsatisfactory, with a 5-year survival rate of <30%. Studies have indicated that Huaier granules have good antitumor efficacy and safety in several solid malignant tumors. Recent studies have also found that Huaier polysaccharides can promote apoptosis in numerous tumor cells, although only few studies have focused on the effects of Huaier granules on gastric cancers and the mechanisms underlying their antitumor role. We retrospectively evaluated stage IIb gastric cancer patients at Xiangya Hospital, Central South University, through our outpatient system from January 2013 to December 2015. Fifty-four patients were in the Huaier+Tegafur Gimeracil Oteracil Potassium (TGOP) group and 72 in the TGOP group. Further, we conducted CCK8, colony formation, Annexin V-FITC/PI, Western blot, RT-PCR, and plasmid transfection assays to analyze the mechanism by which Huaier polysaccharides play an antitumor role. We confirmed that Huaier granules combined with Tegafur Gimeracil Oteracil Potassium could promote patient prognosis, with a better disease-free survival rate (51.32 ± 2.23 vs. 44.19 ± 2.26, p = 0.034) and overall survival rate (56.81 ± 1.32 vs. 51.32 ± 1.69, p = 0.020). Moreover, through cell proliferation assays, Western blot, RT-PCR, and detection of Livin expression at the mRNA and protein levels, we found that Huaier polysaccharides could promote gastric cancer cell apoptosis and inhibit gastric cancer cell proliferation in a time- and dose-dependent manner. Finally, we demonstrated that Huaier polysaccharides promote gastric cancer cell apoptosis through the regulation of Livin expression. Overexpression of Livin reversed the gastric cell apoptosis induced by Huaier polysaccharides. Huaier granules combined with Tegafur Gimeracil Oteracil Potassium ameliorated stage IIb gastric cancer prognosis and induced gastric cancer cell apoptosis by regulating Livin.

Study on the relationship between livin expression and osteosarcoma

OBJECTIVE

The aim of this meta-analysis was to analysis the expression of livin in human osteosarcoma.

METHODS

We searched the Pubmed, Science Direct, Embase and Web of Science, CNKI, Wanfang and VIP for relevant original studies. Statistical analysis was performed by Stata 11.0 software.

RESULTS

Our study indicated that livin expressed in the osteosarcoma tissue was significantly higher than the control group (OR = 18.814, P c = 0.000, 95% CI: 10.973-32.257), and the positive expression of livin was correlated with the size of osteosarcoma tumor and Enncking staging (OR = 4.832, 95% CI: 2.198-10.621; OR = 4.851, 95% CI: 3.053-7.709, respectively).

CONCLUSION

Livin was highly expressed in osteosarcoma, and osteosarcoma Enncking staging and tumor size were positively correlated, both may be involved in the occurrence and development of osteosarcoma, and be closely related to the prognosis of osteosarcoma patients.

Inhibitors of apoptosis: clinical implications in cancer

Inhibitor of apoptosis (IAP) family comprises a group of endogenous proteins that function as main regulators of caspase activity and cell death. They are considered the main culprits in evasion of apoptosis, which is a fundamental hallmark of carcinogenesis. Overexpression of IAP proteins has been documented in various solid and hematological malignancies, rendering them resistant to standard chemotherapeutics and radiation therapy and conferring poor prognosis. This observation has urged their exploitation as therapeutic targets in cancer with promising pre-clinical outcomes. This review describes the structural and functional features of IAP proteins to elucidate the mechanism of their anti-apoptotic activity. We also provide an update on patterns of IAP expression in different tumors, their impact on treatment response and prognosis, as well as the emerging investigational drugs targeting them. This aims at shedding the light on the advances in IAP targeting achieved to date, and encourage further development of clinically applicable therapeutic approaches.

Expression of antiapoptotic proteins livin and survivin in pediatric AML patients, as prognostic markers

OBJECTIVE

Survivin and livin are highly expressed in various malignancies and their expression levels may be related to unfavorable prognosis. The aim was to investigate the relationships of these two markers with some prognostic factors and with survival of the children with acute myeloid leukemia (AML).

METHODS

Livin and survivin expression was investigated quantitatively by immunohistochemistry staining technique in 43 primary formalin-fixed, paraffin-embedded bone marrow blocks in pediatric age group (<18 years).

RESULTS

Both survivin and livin were expressed in 81.4% of AML patients. Livin expression showed significant positive association with high level of primary WBC (p = .002). Survivin expression showed significant positive correlations with risk of relapse (p ≤ .001) and high level of primary WBC (p = .003). The relationship of overall survival (OS) of the patients with livin and survivin expression, were investigated separately in disease subtypes. Significant association was observed between survivin expression and shorter OS regardless of subtypes including acute promyelocytic (APL) (p = .01) and nonacute promyelocytic leukemia (non-APL) (p = .008). Also, significant association of livin expression with shorter OS was detected, but only in APL subgroup (p = .046). Nevertheless, in Cox regression model after adjusting for disease subtypes, stage and cytogenetics; survivin and livin showed no significant association with OS (p > .05).

CONCLUSION

Livin and survivin showed significant associations with some poor prognostic factors of AML. Although survivin in both subtypes and livin in non APL subtype, showed a significant relationship with shorter OS, none of them was determined as independent prognostic factors. Further studies with larger sample size are suggested.

Silencing Livin improved the sensitivity of colon cancer cells to 5-fluorouracil by regulating crosstalk between apoptosis and autophagy

Colorectal cancer (CRC) is the third most common cause of cancer-associated mortality worldwide. Currently, 5-fluorouracil (5-FU) remains a widely used chemotherapeutic drug in the treatment of CRC; however, 5-FU resistance during treatment has become a common problem. Livin, a member of the inhibitor of apoptosis protein family, is considered to be associated with tumor resistance to chemotherapy. In the present study, Livin-silenced cells were generated by introducing a lentivirus into HCT116 and SW620 colon cancer cell lines. Acridine orange/ethidium bromide staining was used as an indicator of cell death. Western blot analysis was performed to detect protein expression levels, and transmission electron microscopy was used to assess autophagy. The half-maximal inhibitory concentration of 5-FU in colon cancer cells was evaluated using a Cell Counting Kit-8 assay. The results of the present study confirmed that silencing Livin significantly enhanced colon cancer cell death in the presence of 5-FU, increased expression levels of various apoptosis- and autophagy-associated proteins and augmented chemotherapeutic sensitivity to 5-FU. Furthermore, the present study demonstrated that this effect may be reversed when autophagy or apoptosis was inhibited, indicating that apoptosis and autophagy were involved in this process. The protein kinase B signaling pathway and B-cell lymphoma-2 expression levels significantly decreased following Livin knockdown, suggesting they may contribute to the regulation of apoptosis and autophagy crosstalk, which caused the Livin knockdown-induced cell death observed.

Correlations of ICAM-1 gene polymorphisms with susceptibility and multidrug resistance in colorectal cancer in a Chinese population

BACKGROUND

Colorectal cancer (CRC) is a malignant gastrointestinal tumor with a high mortality rate, including both colon and rectal cancer. In order to provide clinical guidance for the treatment of CRC, this study is conducted to investigate the correlations of intercellular adhesion molecule 1 (ICAM-1) gene polymorphisms with susceptibility and multidrug resistance (MDR) of colorectal cancer (CRC).

METHODS

A total of 195 patients with CRC were selected as the observation group and 188 healthy people enrolled as the control group. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) was used to test ICAM-1 A13848G and K469E polymorphisms. The expressions of MDR-associated protein topoisomerase II (Topo II) and P-glycoprotein (P-gp) in CRC tissues were detected by immunohistochemistry. The analysis on association of clinical indexes of CRC patients with ICAM-1 gene polymorphisms was performed.

RESULTS

The frequencies of KK genotype and K allele of K469E in the observation group were significantly higher than that in the control group. KE + EE genotype and E allele might be protective factors for CRC. The distribution of genotypes, K469E KK and KE+EE, was highly correlated with histologic grade of tumor differentiation. Compared with adjacent normal tissues, positive rates of Topo II and P-gp expression were significantly increased in CRC tissues. Topo II expression in CRC patients was positively associated with lymph node metastasis and depth of tumor invasion, whereas P-gp expression was only associated with depth of tumor invasion. Higher positive rates of Topo II and P-gp expression were observed in ICAM-1 K469E KK genotype carriers, indicating that ICAM-1 K469E KK genotype might be related to MDR in CRC.

CONCLUSION

These findings in the current study suggested that ICAM-1 K469E polymorphism is highly correlated with susceptibility and MDR in CRC.

Livin enhances chemoresistance in head and neck squamous cell carcinoma

The responsiveness of head and neck squamous cell carcinoma (HNSCC) to chemotherapy widely affects prognosis. Overcoming chemoresistance is necessary to improve prognoses in patients with advanced HNSCC. Evasion of apoptosis by cancer cells is a major cause of chemoresistance. Livin, a member of the human inhibitors of apoptosis protein family, is highly expressed in various human cancer tissues and is associated with tumor progression and poor prognosis in human cancers. The aim of the present study was to evaluate the role of Livin in the susceptibility to popularly used chemotherapeutic drugs such as cisplatin, 5-fluorouracil (FU) and docetaxel in human HNSCC cell lines (SNU1041, PCI1 and PCI50 cells). Reverse transcription polymerase chain reaction and western blotting were performed to determine mRNA and protein expression levels. Cell viability and apoptosis assays were used to assess the functional effects of small-interfering RNA-mediated knockdown of Livin. Each HNSCC cell line had different sensitivity to chemotherapeutic drugs. Livin knockdown significantly enhanced cytotoxicity to cisplatin, 5-FU and docetaxel in human HNSCC cells. Livin knockdown induced apoptosis and enhanced chemotherapy-induced apoptosis to cisplatin, 5-FU and docetaxel. Consistent with this, Livin-knockdown cells showed greater expression of cleaved caspases-3 and -7 and poly(ADP-ribose)polymerase compared with that in control cells after cisplatin, 5-FU, or docetaxel treatment. In conclusion, our results suggest that siRNA-mediated Livin knockdown enhanced the chemosensitivity of the three HNSCC cell lines to cisplatin, 5-FU and docetaxel. Although further investigations are required to support these findings, our results demonstrated that novel therapeutic strategies with combined use of siRNA targeting Livin and chemotherapeutic agents may have applications in the treatment of advanced HNSCC.

Tuberostemonine reverses multidrug resistance in chronic myelogenous leukemia cells K562/ADR

Objective: To investigate the reversal effect of tuberostemonine on MDR in myelogenous leukemia cells K562/ADR.

Methods: Human myelogenous leukemia cells K562 and their adriamycin-resistance cells K562/ADR were used. The growth curve of cells treated by tuberostemonine and the Non-toxic concentration of tuberostemonine were determined by MTT, Cell apoptosis was determined by MTT and flow cytometry. The expression of MDR1, Survivin and Livin was detected by RT-PCR. The activity of P-gp was detected by flow cytometry. Western blot was used to detect the expression of NF-κB and Survivin.

Results: The effect of tuberostemonine on K562/ADR showed a dose-dependence, and 350μg/mL and 500μg/mL of tuberostemonine could inhibit the expression of MDR1 (P<0.05). While no function difference of P-gp was detected. With the increased concentration of tuberostemonine, the inhibitory effect were enhanced to the expression of NF-κB. Tuberostemonine combined with adriamycin could time-dependently inhibit the cell proliferation (P<0.05) and obviously promoted the cell apoptosis (P<0.05). Also the tuberostemonine could inhibit the expression of Survivin.

Conclusion: There are no direct relations between tuberostemonine and P-gp, but tuberostemonine could reverse the multidrug resistance of K562/ADR via down-regulating the expression of Nf-κB and inhibiting th1e expression of Survivin.

BIRC7 and KLF4 expression in benign and malignant lesions of pancreas and their clinicopathological significance

This study investigated the KLF4 and BIRC7 protein expression in malignant and benign pancreatic tissues by immunohistochemical staining and the clinical and pathological significance of KLF4 and BIRC7 expression in PDAC. KLF4 expression was significantly lower, whereas BIRC7 expression was significantly higher in PDAC than that in peritumoral tissue, benign pancreatic lesions, and normal pancreatic tissue (P < 0.01). The percentage of positive BIRC7 and negative KLF4 expression was significantly lower in PDAC patients with well differentiated tumors, maximum tumor size < 3 cm, no lymph node metastasis, no invasion to the surrounding tissues and organs, and TNM stage I/II stage disease than in patients with poorly differentiated tumor, maximum tumor size > 5 cm, lymph node metastasis, invasion to surrounding tissues and organs, and TNM stage III/IV disease (P < 0.05 or P < 0.01). Kaplan-Meier survival analysis showed that the differentiation, maximum tumor size, TNM stage, lymph node metastasis, invasion, negative KLF4 expression, and positive BIRC7 expression were significantly associated with the short survival of patients with PDAC (P < 0.05 or P < 0.01). Cox multivariate analysis revealed that positive BIRC7 expression and negative KLF4 expression were independent poor prognosis factors in PDAC patients. In conclusions, positive BIRC7 expression and negative KLF4 expression are associated with the progression of PDAC and poor prognosis in patients with PDAC.

Silencing the livin gene enhances the cytotoxic effects of anticancer drugs on colon cancer cells

Purpose

Livin is associated with drug response in several cancers. The aim of this study was to investigate the effect of silencing the livin gene expression on anticancer drug response in colorectal cancer.

Methods

siRNA was transfected at different concentrations (0, 10, and 30nM) into HCT116 cells, then cells were treated with either 5-fluorouracil (FU)/leucovorin (LV) or oxaliplatin (L-OHP)/5-FU/LV. Cellular viability and apoptosis were evaluated following silencing of livin gene expression combined with treatment with anticancer drugs.

Results

Livin gene expression was effectively suppressed by 30nM siRNA compared with control and 10nM siRNA. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay showed that proliferation was effectively inhibited in cells treated with a combination of both siRNA and an anticancer drug, compared to cells treated with siRNA-Livin or anticancer drug alone. In particular, the combination of 30nM siRNA and L-OHP/5-FU/LV resulted in a 93.8% and 91.4% decrease, compared to untreated control or L-OHP/5-FU/LV alone, respectively. Cellular proliferation was most effectively suppressed by a combination of 30nM of siRNA and L-OHP/5-FU/LV compared to other combinations.

Conclusion

siRNA-mediated down-regulation of livin gene expression could significantly suppress colon cancer growth and enhance the cytotoxic effects of anticancer drugs such as 5-FU and L-OHP. The results of this study suggest that silencing livin gene expression in combination with treatment with anticancer drugs might be a novel cancer therapy for colorectal cancer.

The effects of Livin shRNA on the response to cisplatin in HepG2 cells

Hepatocellular carcinoma is a lethal malignancy with poor prognosis, partially due to tumor metastasis, recurrence and resistance to chemo- or radio-therapy. Cisplatin can inhibit cancer cell DNA replication, and is widely used in the clinical treatment of tumors. The present study aimed to generate eukaryotic expression vectors for Livin shRNA and to examine the effects of Livin shRNA on the chemosensitivity of HepG2 hepatocellular carcinoma cells. Eukaryotic expression vectors for Livin shRNA (pSD11-U6/Neo/GFP/Livin) were designed and constructed. The HepG2 hepatocellular carcinoma cell line was transfected with this vector using the liposome method. The expression levels of Livin mRNA and protein were measured by quantitative polymerase chain reaction and western blot analysis. The rate of cell growth inhibition was measured using MTT assay following treatment of the cells with cisplatin (2.0 mg/l). DNA sequencing confirmed that the construction of the eukaryotic expression vector for Livin shRNA had been successful. Transfection of these vectors into HepG2 cells led to a significant reduction in the expression levels of Livin mRNA and protein (P<0.05). Cisplatin treatment was associated with significantly higher rates of cell growth inhibition in HepG2 cells transfected with Livin shRNA compared with those that were not transfected (P<0.05). The vectors constructed in the present study produced effective inhibition of the Livin gene in HepG2 cells and increased the chemosensitivity of hepatocellular carcinoma cells.

Gonadotropin-mediated chemoresistance: Delineation of molecular pathways and targets

Background

Human chorionic gonadotropin (hCG) has essential roles in pregnancy. Reports linking hCG in non-trophoblastic tumors with poor patient prognosis has spurred interest in patho-physiological roles the hormone might play.

Methods

The ability of hCG to prevent tumor cell death and sustain viability in the presence of chemotherapeutic drugs was assessed and potential synergies with TLR ligands explored. hCG-induced up-modulation of genes involved in chemoresistance was documented and targets validated by siRNA knock-down. Whether hCG could drive collaboration between tumor cells and macrophages in the production of IL-6 and consequent chemoresistance was assessed. The effects of concurrent anti-hCG immunization and chemotherapy on the growth of syngeneic murine tumors were evaluated.

Results

hCG maintained basal levels of cytokine secretion by tumor cells exposed to chemotherapeutic drugs, and enhanced viability and proliferation; pre-treatment with hCG also decreased apoptosis, as assessed by Annexin-V binding and the cleavage of caspase 3. While co-incubation with hCG along with several TLR ligands mediated heightened chemo-resistance, TLR-2/6 and TLR-9 ligands increased the phosphorylation of JNK, and TLR-2 and TLR-8 ligands the phosphorylation of ERK in presence of hCG and curcumin, providing evidence of tri-molecular synergy. The hormone increased the transcription and/or expression of molecular intermediates (SURVIVIN, HIF-1α, PARP-1, Bcl-2, c-FLIP, KLK-10, XIAP, c-IAP-1) associated with chemo-resistance and increased levels of stress modulators (PON2, HO-1, HSP27 and NRF-2). siRNAs to SURVIVIN, NRF-2, HO-1 and HIF-1α attenuated hCG-mediated chemo-resistance. hCG-conditioned tumor cell supernatants induced heightened secretion of IL-6 and TNF-α from peripheral blood adherent cells and secreted IL-6 imparted chemo-resistance to naïve tumor cells. Co-administration of curcumin along with an anti-hCG vaccine (hCGβ conjugated to Tetanus Toxoid (TT)) to mice carrying syngeneic tumors resulted in significantly enhanced benefits on animal survival; synergy was demonstrated between anti-hCG antibodies and curcumin in the reduction of tumor cell viability.

Conclusions

The data suggest that hCG, via direct as well as collaborative effects with TLR ligands and accessory cell-secreted cytokines, mediates chemo-resistance in gonadotropin-sensitive tumors and outlines the potential benefits of combination therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1938-x) contains supplementary material, which is available to authorized users.

Inside the biochemical pathways of thymidylate synthase perturbed by anticancer drugs: Novel strategies to overcome cancer chemoresistance

Our current understanding of the mechanisms of action of antitumor agents and the precise mechanisms underlying drug resistance is that these two processes are directly linked. Moreover, it is often possible to delineate chemoresistance mechanisms based on the specific mechanism of action of a given anticancer drug. A more holistic approach to the chemoresistance problem suggests that entire metabolic pathways, rather than single enzyme targets may better explain and educate us about the complexity of the cellular responses upon cytotoxic drug administration. Drugs, which target thymidylate synthase and folate-dependent enzymes, represent an important therapeutic arm in the treatment of various human malignancies. However, prolonged patient treatment often provokes drug resistance phenomena that render the chemotherapeutic treatment highly ineffective. Hence, strategies to overcome drug resistance are primarily designed to achieve either enhanced intracellular drug accumulation, to avoid the upregulation of folate-dependent enzymes, and to circumvent the impairment of DNA repair enzymes which are also responsible for cross-resistance to various anticancer drugs. The current clinical practice based on drug combination therapeutic regimens represents the most effective approach to counteract drug resistance. In the current paper, we review the molecular aspects of the activity of TS-targeting drugs and describe how such mechanisms are related to the emergence of clinical drug resistance. We also discuss the current possibilities to overcome drug resistance by using a molecular mechanistic approach based on medicinal chemistry methods focusing on rational structural modifications of novel antitumor agents. This paper also focuses on the importance of the modulation of metabolic pathways upon drug administration, their analysis and the assessment of their putative roles in the networks involved using a meta-analysis approach. The present review describes the main pathways that are modulated by TS-targeting anticancer drugs starting from the description of the normal functioning of the folate metabolic pathway, through the protein modulation occurring upon drug delivery to cultured tumor cells as well as cancer patients, finally describing how the pathways are modulated by drug resistance development. The data collected are then analyzed using network/netwire connecting methods in order to provide a wider view of the pathways involved and of the importance of such information in identifying additional proteins that could serve as novel druggable targets for efficacious cancer therapy.

NEDD8 Inhibition Overcomes CKS1B-Induced Drug Resistance by Upregulation of p21 in Multiple Myeloma

PURPOSE

CKS1B is significantly upregulated in multiple myeloma and associated with poor prognosis. The identification of novel therapies is essential for effective treatment of patients resistant to chemotherapy. The NEDD8 inhibitor MLN4924 selectively targets SCF(Skp2) activation and offers a more specific approach to protein degradation inhibition than total proteasomal inhibition. The goal of this study was to evaluate whether MLN4924 is effective in high CKS1B conditions and identify mechanisms regulating drug potency.

EXPERIMENTAL DESIGN

Bortezomib and MLN4924 sensitivity was assessed through proliferation, viability, clonogenic potential, and senescence induction in cells overexpressing CKS1B. The mechanism for MLN4924 sensitivity was elucidated by immunoblot analysis of SCF(skp) substrates and confirmed by shRNA knockdown. The clinical relevance of the NEDD8 pathway was examined in gene expression profiles (GEP) derived from healthy people, patients with monoclonal gammopathy of undetermined significance (MGUS), and multiple myeloma.

RESULTS

Cells overexpressing CKS1B were resistant to bortezomib but sensitive to MLN4924. Treatment of CKS1B-overexpressing cells with MLN4924 decreased proliferation, clonogenicity, and induced senescence. MLN4924, but not bortezomib, induced stabilization of p21 and knockdown of p21 resulted in loss of MLN4924 sensitivity. Patients with MGUS and multiple myeloma exhibited increased expression of NEDD8 pathway genes relative to normal plasma cells. Multiple myeloma patients with high NEDD8 expression were linked to bortezomib resistance in clinical trials, and had inferior outcomes.

CONCLUSIONS

Our data demonstrate that cells with elevated CKS1B expression are resistant to bortezomib but sensitive to MLN4924 and offer a mechanism through the stabilization of p21. These findings provide rationale for targeting the NEDD8 pathway in multiple myeloma patients exhibiting elevated expression of CKS1B. Clin Cancer Res; 21(24); 5532-42. ©2015 AACR.

Inhibition of livin expression suppresses cell proliferation and enhances chemosensitivity to cisplatin in human lung adenocarcinoma cells

Livin is a novel member of the inhibitor of apoptosis protein family that has been reported to be overexpressed in various types of human malignancy. Although several studies have demonstrated that livin may be used as an effective target for tumor therapy, few studies have investigated its role in human lung adenocarcinoma. In the present study, two different methods were used in order to investigate the tumor‑suppressing effect of livin in human lung adenocarcinoma cells. Firstly, small interfering (si)RNA technology was used to down regulate livin expression; siRNA-mediated knockdown of livin was confirmed using reverse transcription quantitative polymerase chain reaction and western blot analysis, and cell proliferations was assessed using an MTT assay in vitro. Secondly, inhibition of livin expression was induced through the synergistic inhibitory effect between flavopiridol and tumor necrosis factor‑related apoptosis-inducing ligand (TRAIL). Experimental results revealed that, following transfection of the livin gene-silencing vector, the gene expression of livin was markedly decreased, SPC-A1 cell proliferation was significantly reduced and the therapeutic effect of the chemotherapy drug cisplatin was markedly improved. This growth inhibitory effect was also observed in the flavopiridol and TRAIL combination treatment group. In the flavopiridol and TRAIL combination treatment group, the protein expression of livin was significantly reduced and the survival rate of SPC‑A1 cells was significantly lower than the flavopiridol and TRAIL single operation group. In conclusion, the RNA silencing and the synergistic inhibitory effect between flavopiridol with TRAIL was able to effectively inhibit the expression of livin, significantly decrease SPC-A1 tumor cell proliferation and significantly enhance sensitivity to the chemotherapy drug cisplatin. These findings suggest that livin may be used as a novel target for tumor gene therapy.

Knockdown of Livin inhibits growth and invasion of gastric cancer cells through blockade of the MAPK pathway in vitro and in vivo

Livin, a novel member of the human inhibitors of apoptosis protein family, has been shown to be critical for tumor progression and poor prognosis for several types of malignancies. However, limited reports exist regarding the biological functions of Livin in human gastric cancer (GC). The present study investigated the clinical significance of Livin and caspase-3 (CAS-3) in human GC using immunohistochemistry assay, and explore the potential using RNA interference to knockdown Livin expression, including the subsequent effects on tumor growth and invasion in GC cells in vitro and in vivo. Our results showed that the rate of positive expression of Livin was significantly higher in GC tissues compared to that in adjacent non-cancer tissues (ANCT) (64.1 vs. 30.8%, P<0.001), while CAS-3 was lower in GC tissues than in ANCT (33.3 vs. 66.7%, P=0.001). Livin expression was positively correlated with tumor differentiation and lymph node metastases (P=0.009; P=0.007), while CAS-3 was negatively correlated with them (P=0.036; P=0.002) in patients with GC. Furthermore, knockdown of Livin inhibited cell proliferative activities and invasive potential, and induced cell in situ apoptosis in GC cells, accompanied with decreased expression of p38 MAPK, VEGF and MMP-2 and increased expression of CAS-3. In addition, the tumor volumes in the SGC7901 subcutaneous nude mouse model treated with Lv-shLivin was significantly smaller compared to those of the PBS group (P<0.01). Taken together, our findings indicate that the expression of Livin is increased in human GC and correlates with tumor differentiation and lymph node metastases, while knockdown of Livin inhibits cell growth and invasion through blockade of the MAPK pathway in GC cells, suggesting that Livin may be a potential therapeutic target for the treatment of GC.

CpG oligodeoxynucleotides enhance chemosensitivity of 5-fluorouracil in HepG2 human hepatoma cells via downregulation of the antiapoptotic factors survivin and livin

Background

Recent studies indicated that a synthetic oligonucleotide containing un-methylated CpG oligodeoxynucleotides (CpG-ODN) has a potential function for cancer therapy. In this study, we evaluated the chemosensitizing effects of CpG-ODN in 5-fluorouracil (5-FU)-treated HepG2 human hepatoma cells.

Methods

Cell viability assay were utilized to evaluate the direct cytotoxicity of CpG-ODN in the presence or absence of 5-FU in HepG2 cells, and apoptosis as well as cell-cycle was examined by flow cytometry analysis. The mRNA expression of Bcl-2, Livin and Survivin within HepG2 cells treated with CpG-ODN and/or 5-FU were analyzed by Real Time PCR assay in vitro.

Results

CpG-ODN in combination with 5-FU could decrease cell viability, increase apoptosis and further induce HepG2 cells cycle arrest at S phase when compared with CpG-ODN or 5-FU. CpG-ODN or 5-FU could down-regulate the mRNA expression of Bcl-2 within HepG2 cells. The mRNA expression of Livin and Survivin decreased in cells treated with CpG-ODN alone but increased in cells treated with 5-FU alone. However, CpG-ODN in combination with 5-FU could down-regulate the mRNA expression of Livin and Survivin within HepG2 cells.

Conclusions

Our finding demonstrated that CpG-ODN enhanced the chemosentivity of 5-FU in HepG2 human hepatoma cells at least in part by down-regulating the expression of Livin and Survivin, leading to apoptosis and further inducing cell cycle arrest at S phase. Therefore, CpG-ODN may be a potential candidate as chemosensitizer for human hepatocellular carcinoma.

Double siRNA-targeting of cIAP2 and LIVIN results in synergetic sensitization of HCT-116 cells to oxaliplatin treatment

Purpose

Most colon cancers show low sensitivity to treatment with oxaliplatin and a specific strategy is needed to overcome this problem. Our approach uses RNA interference to silence the expression of target genes responsible for the development of oxaliplatin resistance. Profile analysis of genes related to the regulation of apoptosis allowed identification of target genes showing the greatest degree of upregulation in response to oxaliplatin exposure.

Methods

We designed a panel of genes with functions closely related to inactivation of the caspase cascade, endoplasmic reticulum stress reduction, and drug metabolism. The candidate genes were silenced by means of specific small interfering RNA (siRNA) oligonucleotides.

Results

The caspase 3 and 9 inhibitors of apoptosis 2 (cIAP2) and LIVIN were found to be the most dose-responsive genes during the period of oxaliplatin treatment. Two-fold sensitization of cells to oxaliplatin was observed with independent knockdown of either cIAP2 or LIVIN expression. siRNA-silencing of both targets produced a five-fold increase in oxaliplatin sensitivity of HCT-116 cells.

Conclusion

A dose-dependent approach revealed reliable targets for siRNA-silencing under low doses of oxaliplatin. Targeting the key proapoptotic chain with several specific siRNAs resulted in synergetic sensitization of HCT-116 cells to oxaliplatin treatment.

IAP proteins as targets for drug development in oncology

The inhibitors of apoptosis (IAPs) constitute a family of proteins involved in the regulation of various cellular processes, including cell death, immune and inflammatory responses, cell proliferation, cell differentiation, and cell motility. There is accumulating evidence supporting IAP-targeting in tumors: IAPs regulate various cellular processes that contribute to tumor development, such as cell death, cell proliferation, and cell migration; their expression is increased in a number of human tumor samples, and IAP overexpression has been correlated with tumor growth, and poor prognosis or low response to treatment; and IAP expression can be rapidly induced in response to chemotherapy or radiotherapy because of the presence of an internal ribosome entry site (IRES)-dependent mechanism of translation initiation, which could contribute to resistance to antitumor therapy. The development of IAP antagonists is an important challenge and was subject to intense research over the past decade. Six molecules are currently in clinical trials. This review focuses on the role of IAPs in tumors and the development of IAP-targeting molecules for anticancer therapy.

Expression of Livin in colorectal cancer and its relationship to tumor cell behavior and prognosis

BACKGROUNDS

Expression of Livin, a member of the inhibitors of apoptosis protein family, is associated with tumor development and progression. The aims of this study were to evaluate whether Livin affects oncogenic biological behavior of colorectal cancer cells, and to document the relationship between its expression and various clinicopathological parameters in colorectal cancer.

METHODS

We investigated the impact of Livin on tumor cell behavior by using the small interfering RNA and pcDNA3.1 vector in SW480 and DKO1 colorectal cancer cell lines. The expression of Livin was investigated by RT-PCR and immunohistochemistry in coloretcal cancer tissues. The apoptotic cells were visualized by TUNEL assay, and proliferative cells were visualized by Ki-67 antibody staining.

RESULTS

Knockdown of Livin suppressed tumor cell migration and invasion in colorectal cancer cells. Knockdown of Livin induced the apoptosis by up-regulating of caspase-3, -7 and PARP activities and the cell cycle arrest by decreasing cyclin D1, cyclin D3, cyclin-dependent kinase 4 and 6, and by inducing p27 expression. The MAPK signaling cascades were significantly blocked by knockdown of Livin. In contrast, overexpression of Livin enhanced tumor cell migration and invasion, and inhibited the apoptosis and cell cycle arrest. The mean apoptotic index (AI) value of Livin positive tumors was significantly lower than AI of Livin negative tumors. However, there was no significant difference between Livin expression and Ki-67 labeling index (KI). Livin expression was significantly increased in colorectal cancer and metastatic lymph node tissues compared to normal colorectal mucosa and non-metastatic lymph node tissues and was associated with tumor stage, lymphovascular invasion, lymph node metastasis and poor survival.

CONCLUSIONS

These results indicate that Livin is associated with tumor progression by increasing tumor cell motility and inhibiting apoptosis in colorectal cancer.

RNA interference-mediated knockdown of Livin suppresses cell proliferation and invasion and enhances the chemosensitivity to cisplatin in human osteosarcoma cells

Livin is a novel member of the inhibitor of apoptosis protein (IAP) family that has been reported to be overexpressed in a variety of human malignancies, including osteosarcoma. However, the potential roles of Livin in tumorigenesis have not been elucidated. In the present study, we employed RNA interference (RNAi) technology to suppress endogenous Livin expression in osteosarcoma cells and successfully generated a U2-OS cell line with stably knockdown of Livin. Functional analysis showed that knockdown of Livin significantly reduced cell proliferation, colony formation, and invasion and migration capacities of U2-OS cells in vitro. Moreover, specific downregulation of Livin led to cell cycle arrest at the G0/G1 phase and eventual apoptosis. Meanwhile, western blot analysis revealed that cells with stably knockdown of Livin showed decreased expression levels of Cyclin D1, Bcl-2, matrix metalloproteinase (MMP)-2 and MMP-9, but increased expression levels of activated Caspase-3, Bax and cleaved poly (ADP-ribose) polymerase (PARP) compared to those transfected with a control vector. We also observed that suppression of Livin expression in osteosarcoma cells increased their chemosensitivity to cisplatin. Taken together, our data suggest that Livin is involved in tumorigenesis of human osteosarcoma and may serve as a promising therapeutic target for osteosarcoma.

Upregulation of the antiapoptotic factor Livin contributes to cisplatin resistance in colon cancer cells

The antiapoptotic factor Livin has been considered critical for tumor progression and poor prognosis for variant types of tumors. However, there are only limited reports regarding its expression and biological functions in colon cancer. Here, we examined Livin expression in four colon cancer cell lines (HCT116, RKO, KM12C, and SW620) in the presence or absence of cisplatin that was used as a model reagent. We found the different response to cisplatin was related to endogenous Livin expression level. From among a panel of apoptosis-related factors (p53, Bcl-2, Bcl-XL, BAX, and survivin), the expression of Livin was upregulated after cisplatin treatment in a dose-dependent manner. Both immunocytochemistry and nuclear cytoplasmic fractionation indicated Livin remained in the cytoplasm after treatment with cisplatin. In an attempt to explore the mechanism, we found the elevated expression of Livin was not due to the decreased degradation by proteosome but was enhanced at the mRNA level. Besides, cisplatin treatment activated the mammalian target of rapamycin (mTOR) pathway as shown by increased phosphorylation of Akt1, mTOR, S6K, and 4E-BP1, together with the elevated Livin. The PI3K inhibitor LY294002 inhibited both the phosphorylation of mTOR and upregulation of Livin. The stable overexpression of Livin inhibited the activation of caspase-3 and led to resistance to cisplatin, while the knockdown of Livin by siRNA rendered colon cancer cells more sensitive to cisplatin. Our study, along with others, highlighted the potential of Livin for cancer therapy in colon cancer.

Application of RNA interference in research of multidrug resistance in colorectal cancer: Recent progress

Colorectal cancer is one of the most common malignant digestive tract tumors in the world. Chemotherapy is the main treatment for colorectal cancer. However, multidrug resistance of tumor cells hinders its treatment. RNA interference, which allows specifically inhibiting the expression of multidrug genes, has been gradually applied to gene treatment for multidrug resistance. This paper aims to summarize the progress of application of RNA interference in research of multidrug resistance in colorectal cancer.

Role of melanoma inhibitor of apoptosis (ML-IAP) protein, a member of the baculoviral IAP repeat (BIR) domain family, in the regulation of C-RAF kinase and cell migration

Inhibitor of apoptosis (IAPs) proteins are characterized by the presence of evolutionarily conserved baculoviral inhibitor of apoptosis repeat (BIR) domains, predominantly known for their role in inhibiting caspases and, thereby, apoptosis. We have shown previously that multi-BIR domain-containing IAPs, cellular IAPs, and X-linked IAP can control tumor cell migration by directly regulating the protein stability of C-RAF kinase. Here, we extend our observations to a single BIR domain containing IAP family member melanoma-IAP (ML-IAP). We show that ML-IAP can directly bind to C-RAF and that ML-IAP depletion leads to an increase in C-RAF protein levels, MAPK activation, and cell migration in melanoma cells. Thus, our results unveil a thus far unknown role for ML-IAP in controlling C-RAF stability and cell migration.