Induction of apoptosis by tumor suppressor FHIT via death receptor signaling pathway in human lung cancer cells

Spleen proteome profile reveals immune responses induced by dietary spray-dried plasma against Salmonella Enteritidis infection in broiler chicks

Salmonella infection severely impacts poultry health, productivity, and food safety. Spray dried plasma (SDP) shows good efficacy as an alternative to in-feed antibiotics for broiler chickens. Our objective was to identify potential mechanisms of SDP benefits by analyzing effects on spleen proteome and in response to Salmonella Enteritidis challenge (SE). A 2 × 2 factor study of broilers (n = 240) were assigned to CON (control) or SDP (30g/kg) diet at 1 day of age, and gavaged with sterile tryptic soy or 7.46 × 108 CFU SE /mL, resulting in 4 groups CON (n = 60), SDP (n = 60), CON-SE (n = 60) and SDP-SE (n = 60). On d 2 and d 5 post-challenge, chicks (n = 4/treatment) were euthanized, and spleen collected to isolate proteins, and measure using label-free liquid chromatography tandem mass spectrometry. Data were mapped to Gallus gallus Uniprot database, and differentially abundant proteins (DAP; P < 0.05) identified using ANOVA. Across all samples, 4,300 proteins were identified, and SDP treatment resulted 116 DAP. Proteins (56) that decreased were associated with positive regulation of I-kappaß kinase/NF- kappaß signaling and positive regulation of apoptosis process. Proteins that increased (60) were associated with integral components of endoplasmic reticulum membrane and necroptosis pathway. Analysis of the interaction between SDP and SE challenge found 119 DAP. The proteins that increased (87) were associated with RNA binding, ATP binding, mRNA splicing, and protein phosphorylation. Proteomic signatures of spleen reveals that the actions of SDP in broiler chicks are anti-inflammatory and anti-apoptotic and predicted to inhibit pro-inflammatory response through the inhibition of NF-ĸB. However, in the presence of Salmonella infection, it promotes regulated inflammatory response.

N-Terminal Domain of Fragile Histidine Triad Exerts Potent Cytotoxic Effect in HT1080 Cells and Increases Doxorubicin Cytotoxicity

Fragile histidine triad (FHIT) serves a critical function as a tumor suppressor that inhibits p53 degradation by mouse double minute 2 (MDM2). The functional domains of FHIT involved in tumor inhibition was interpreted. In-silico screening data were employed to construct truncated forms of FHIT to assess their cytotoxic effects on the HT1080 cell line. Full FHIT expression was confirmed by western blotting and expression of two FHIT truncates were confirmed by RT-PCR. Transfection of these truncated forms into HT1080 cells showed that the N-terminal truncated form (amino acids 17-102) better inhibited proliferation than the full-length FHIT. The combined effects of these truncated forms augmented doxorubicin-induced cytotoxicity. Functional analysis demonstrated that these fragments and their combination with doxorubicin can arrest cells in the G2 phase of the cell cycle as specified by flow cytometry. The FHIT functional domains can be used as lead compounds for development of drug designs and gene transfer for cancer therapy.

Association of FHIT expression and FHIT gene hypermethylation with liver cancer risk: a PRISMA-compliant meta-analysis

Background

There have been suggestions that fragile histidine triad protein (FHIT) expression and FHIT gene hypermethylation were crucial to the pathogenesis of liver cancer. However, the conclusions remained unclear because of small sample size, disease subtype, and different detection techniques. Therefore, we performed a meta-analysis to estimate the associations of FHIT expression and FHIT gene hypermethylation with liver cancer pathogenesis.

Methods

Studies that were published in electronic databases, such as PubMed, Web of Knowledge, China National Knowledge Infrastructure (CNKI), VIP, and WanFang, were retrieved and selected for the meta-analysis. Relative risk (RR) and 95% confidence interval (CI) were calculated to determine the correlations of FHIT expression and FHIT gene hyper-methylation with liver cancer pathogenesis with Stata 12.0 software.

Results

A total of 17 papers that evaluated the associations of FHIT expression (14 articles) and FHIT gene methylation (3 articles) with liver cancer pathogenesis were included in this meta-analysis. In the overall analysis, the pooled relative risk was 1.93 (95% CI =1.72–2.17), which indicated a significant association between FHIT low expression and liver cancer risk. According to the results of clinical information, there were significant associations of FHIT expression with TNM-stage (RR =2.13, 95% CI =1.72–2.64), tumor size (RR =1.67, 95% CI =1.36–2.05), and merger of cirrhosis (RR =1.34, 95% CI =1.06–1.69) of liver cancer in the Chinese population. In addition, the FHIT gene hypermethylation was significantly associated with the risk of liver cancer (RR =1.45, 95% CI =1.08–1.93).

Conclusion

The FHIT expression and hypermethylation of FHIT gene were significantly associated with the risk of liver cancer, especially in the Chinese population. Furthermore, the results indicated significant associations between FHIT low expression and TNM-stage, tumor size, and merging of cirrhosis of liver cancer in the Chinese population.

Genetic and Chromosomal Aberrations and Their Clinical Significance in Renal Neoplasms

The most common form of malignant renal neoplasms is renal cell carcinoma (RCC), which is classified into several different subtypes based on the histomorphological features. However, overlaps in these characteristics may present difficulties in the accurate diagnosis of these subtypes, which have different clinical outcomes. Genomic and molecular studies have revealed unique genetic aberrations in each subtype. Knowledge of these genetic changes in hereditary and sporadic renal neoplasms has given an insight into the various proteins and signalling pathways involved in tumour formation and progression. In this review, the genetic aberrations characteristic to each renal neoplasm subtype are evaluated along with the associated protein products and affected pathways. The potential applications of these genetic aberrations and proteins as diagnostic tools, prognostic markers, or therapeutic targets are also assessed.

A comparative proteomic study of Homoharringtonine-induced apoptosis in leukemia K562 cells

The objective of this study was to determine the changes in protein profiles of K562 chronic myeloid leukemia (CML) cells in response to Homoharringtonine (HHT). HHT treatment significantly increased apoptosis of K562 cells. Proteomic analyses indicated 32 differentially expressed proteins, 13 of which were identified by mass spectrometry (nine down-regulated and four up-regulated). Aside from alterations in apoptotic proteins and proteins associated with transcription and translation, our data also revealed changes in oxidative stress response and redox reaction-related proteins, such as heat shock proteins (Hsps), DJ-1 and thioredoxin. Specifically, these proteins were validated to decrease after HHT treatment in K562 cells and in primary CML cells by immunoblot analysis. Additionally, Hsps, DJ-1 and thioredoxin, which were also shown to decrease in primary cells from imatinib-resistant patients, may be promising potential targets for mechanistic research and new clinical treatments.

Computational Survey of FHIT, A Putative Human Tumor Suppressor, Truncates Structure

BACKGROUND

Fragile Histidine Triad protein (FHIT), as a known tumor suppressor protein, has been proposed to play crucial role in inhibiting p53 degradation by MDM2. Studies have confirmed FHIT interaction with p53 or MDM2, although functional interacting domains of FHIT with MDM2 and/or p53 are not completely defined. Thus, through determining the significant structural interacting domains of FHIT, information with regard to MDM2 and p53 would be provided. As there were no previous studies evaluating the interaction of optimized important parts of target molecules, docking study was employed.

METHODS

Truncated structures of FHIT were screened to reveal critical sections engaging in FHIT interaction. HEX program was used in order to study the interaction of target structures.

RESULTS

Given the total energy, FHIT structures (β5-7, α1) and (α1) of FHIT were showed to be better candidates in comparison with other structures in interaction with optimized MDM2 part. Furthermore, FHIT structures (β4-7, α1) and (β5-7, α1) were considered to be better than other structures in interaction with optimized p53 part. FHIT truncates which interact with MDM2 optimized part exhibited lower energy levels than FHIT truncates which interact with p53 optimized part.

CONCLUSION

Our results can be useful for designing new inhibitors of this protein complex interaction which would result in tumor repression.

The role of sphingosine 1-phosphate in inflammation and cancer

The enzymes that catalyze formation of the bioactive sphingolipid, sphingosine 1-phosphate, sphingosine kinase 1 and 2, are predictive markers in inflammatory diseases and cancer as evidenced by data from patients, knockout mice and the use of available molecular and chemical inhibitors. Thus, there is a compelling case for therapeutic targeting of sphingosine kinase. In addition, there are several examples of functional interaction between sphingosine 1-phosphate receptors and sphingosine kinase 1 that can drive malicious amplification loops that promote cancer cell growth. These novel aspects of sphingosine 1-phosphate pathobiology are reviewed herein.

The roles of sphingosine kinase 1 and 2 in regulating the metabolome and survival of prostate cancer cells

We have previously shown that treatment of androgen-sensitive LNCaP cells with the sphingosine kinase (SK) inhibitor SKi (2-(p-hydroxyanilino)-4-(p-chlorophenyl)thiazole) induces the proteasomal degradation of two N-terminal variants of SK1 (SK1a and SK1b), increases C22:0-ceramide and diadenosine 5′,5′′′-P¹,P³-triphosphate (Ap3A) and reduces S1P levels, and promotes apoptosis. We have now investigated the effects of three SK inhibitors (SKi, (S)-FTY720 vinylphosphonate, and (R)-FTY720 methyl ether) on metabolite and sphingolipid levels in androgen-sensitive LNCaP and androgen-independent LNCaP-AI prostate cancer cells. The 51 kDa N-terminal variant of SK1 (SK1b) evades the proteasome in LNCaP-AI cells, and these cells do not exhibit an increase in C22:0-ceramide or Ap3A levels and do not undergo apoptosis in response to SKi. In contrast, the SK inhibitor (S)-FTY720 vinylphosphonate induces degradation of SK1b in LNCaP-AI, but not in LNCaP cells. In LNCaP-AI cells, (S)-FTY720 vinylphosphonate induces a small increase in C16:0-ceramide levels and cleavage of polyADPribose polymerase (indicative of apoptosis). Surprisingly, the level of S1P is increased by 7.8- and 12.8-fold in LNCaP and LNCaP-AI cells, respectively, on treatment with (S)-FTY720 vinylphosphonate. Finally, treatment of androgen-sensitive LNCaP cells with the SK2-selective inhibitor (R)-FTY720 methyl ether increases lysophosphatidylinositol levels, suggesting that SK2 may regulate lyso-PI metabolism in prostate cancer cells.

The roles of sphingosine kinases 1 and 2 in regulating the Warburg effect in prostate cancer cells

Two isoforms of sphingosine kinase, SK1 and SK2, catalyze the formation of the bioactive lipid sphingosine 1-phosphate (S1P) in mammalian cells. We have previously shown that treatment of androgen-sensitive LNCaP prostate cancer cells with a non-selective SK isoform inhibitor, 2-(p-hydroxyanilino)-4-(p-chlorophenyl)thiazole (SKi), induces the proteasomal degradation of SK1. This is concomitant with a significant increase in C22:0-ceramide and sphingosine levels and a reduction in S1P levels, resulting in the apoptosis of LNCaP cells. In contrast, we show here that a SK2-selective inhibitor, (R)-FTY720 methyl ether (ROME), increases sphingosine and decreases S1P levels but has no effect on ceramide levels and does not induce apoptosis in LNCaP cells. We also show that several glycolytic metabolites and (R)-S-lactoylglutathione are increased upon treatment of LNCaP cells with SKi, which induces the proteasomal degradation of c-Myc. These changes reflect an indirect antagonism of the Warburg effect. LNCaP cells also respond to SKi by diverting glucose 6-phosphate into the pentose phosphate pathway to provide NADPH, which serves as an antioxidant to counter an oxidative stress response. SKi also promotes the formation of a novel pro-apoptotic molecule called diadenosine 5',5'''-P(1),P(3)-triphosphate (Ap3A), which binds to the tumor suppressor fragile histidine triad protein (FHIT). In contrast, the SK2-selective inhibitor, ROME, induces a reduction in some glycolytic metabolites and does not affect oxidative stress. We conclude that SK1 functions to increase the stability of c-Myc and suppresses Ap3A formation, which might maintain the Warburg effect and cell survival, while SK2 exhibits a non-overlapping function.

Mitochondrial Ca(2+) and apoptosis

Mitochondria are key decoding stations of the apoptotic process. In support of this view, a large body of experimental evidence has unambiguously revealed that, in addition to the well-established function of producing most of the cellular ATP, mitochondria play a fundamental role in triggering apoptotic cell death. Various apoptotic stimuli cause the release of specific mitochondrial pro-apoptotic factors into the cytosol. The molecular mechanism of this release is still controversial, but there is no doubt that mitochondrial calcium (Ca(2+)) overload is one of the pro-apoptotic ways to induce the swelling of mitochondria, with perturbation or rupture of the outer membrane, and in turn the release of mitochondrial apoptotic factors into the cytosol. Here, we review as different proteins that participate in mitochondrial Ca(2+) homeostasis and in turn modulate the effectiveness of Ca(2+)-dependent apoptotic stimuli. Strikingly, the final outcome at the cellular level is similar, albeit through completely different molecular mechanisms: a reduced mitochondrial Ca(2+) overload upon pro-apoptotic stimuli that dramatically blunts the apoptotic response.

The effect of adenovirus-mediated gene expression of FHIT in small cell lung cancer cells

The candidate tumor suppressor fragile histidine traid (FHIT) is frequently inactivated in small cell lung cancer (SCLC). Mutations in the p53 gene also occur in the majority of SCLC leading to the accumulation of the mutant protein. Here we evaluated the effect of FHIT gene therapy alone or in combination with the mutant p53-reactivating molecule, PRIMA-1(Met)/APR-246, in SCLC. Overexpression of FHIT by recombinant adenoviral vector (Ad-FHIT)-mediated gene transfer in SCLC cells inhibited their growth by inducing apoptosis and when combined with PRIMA-1(Met)/APR-246, a synergistic cell growth inhibition was achieved.

Evaluation of influence of Ap4A analogues on Fhit-positive HEK293T cells; cytotoxicity and ability to induce apoptosis

Fragile histidine triad (Fhit) protein encoded by tumour suppressor FHIT gene is a proapoptotic protein with diadenosine polyphosphate (Ap(n)A, n=2-6) hydrolase activity. It has been hypothesised that formation of Fhit-substrate complex results in an apoptosis initiation signal while subsequent hydrolysis of Ap(n)A terminates this action. A series of Ap(n)A analogues have been identified in vitro as strong Fhit ligands [Varnum, J. M.; Baraniak, J.; Kaczmarek, R.; Stec, W. J.; Brenner, C. BMC Chem. Biol.2001, 1, 3]. We assumed that in Fhit-positive cells these compounds might preferentially bind to Fhit and inhibit its hydrolytic activity what would prolong the lifetime of apoptosis initiation signalling complex. Therefore, several Fhit inhibitors were tested for their cytotoxicity and ability to induce apoptosis in Fhit-positive HEK293T cells. These experiments have shown that Ap(4)A analogue, containing a glycerol residue instead of the central pyrophosphate and two terminal phosphorothioates [A(PS)-CH(2)CH(OH)CH(2)-(PS)A (1)], is the most cytotoxic among test compounds (IC(50)=17.5±4.2 μM) and triggers caspase-dependent cell apoptosis. The Fhit-negative HEK293T cells (in which Fhit was silenced by RNAi) were not sensitive to compound 1. These results indicate that the Ap(4)A analogue 1 induces Fhit-dependent apoptosis and therefore, it can be considered as a drug candidate for anticancer therapy in Fhit-positive cancer cells and in Fhit-negative cancer cells, in which re-expression of Fhit was accomplished by gene therapy.

Adenoviral vector-based strategies for cancer therapy

Definitive treatment of cancer has eluded scientists for decades. Current therapeutic modalities like surgery, chemotherapy, radiotherapy and receptor-targeted antibodies have varied degree of success and generally have moderate to severe side effects. Gene therapy is one of the novel and promising approaches for therapeutic intervention of cancer. Viral vectors in general and adenoviral (Ad) vectors in particular are efficient natural gene delivery systems and are one of the obvious choices for cancer gene therapy. Clinical and preclinical findings with a wide variety of approaches like tumor suppressor and suicide gene therapy, oncolysis, immunotherapy, anti-angiogenesis and RNA interference using Ad vectors have been quite promising, but there are still many hurdles to overcome. Shortcomings like increased immunogenicity, prevalence of preexisting anti-Ad immunity in human population and lack of specific targeting limit the clinical usefulness of Ad vectors. In recent years, extensive research efforts have been made to overcome these limitations through a variety of approaches including the use of conditionally-replicating Ad and specific targeting of tumor cells. In this review, we discuss the potential strengths and limitations of Ad vectors for cancer therapy.

The development of gene therapy: from monogenic recessive disorders to complex diseases such as cancer

During the last 4 decades, gene therapy has moved from preclinical to clinical studies for many diseases ranging from monogenic recessive disorders such as hemophilia to more complex diseases such as cancer, cardiovascular disorders, and human immunodeficiency virus (HIV). To date, more than 1,340 gene therapy clinical trials have been completed, are ongoing, or have been approved in 28 countries, using more than 100 genes. Most of those clinical trials (66.5%) were aimed at the treatment of cancer. Early hype, failures, and tragic events have now largely been replaced by the necessary stepwise progress needed to realize clinical benefits. We now understand better the strengths and weaknesses of various gene transfer vectors; this facilitates the choice of appropriate vectors for individual diseases. Continuous advances in our understanding of tumor biology have allowed the development of elegant, more efficient, and less toxic treatment strategies. In this introductory chapter, we review the history of gene therapy since the early 1960s and present in detail two major recurring themes in gene therapy: (1) the development of vector and delivery systems and (2) the design of strategies to fight or cure particular diseases. The field of cancer gene therapy experienced an "awkward adolescence." Although this field has certainly not yet reached maturity, it still holds the potential of alleviating the suffering of many individuals with cancer.

Losses of 3p14 and 9p21 as shown by fluorescence in situ hybridization are early events in tumorigenesis of oral squamous cell carcinoma and already occur in simple keratosis

Tumorigenesis of oral squamous cell carcinoma (OSCC) has been postulated to represent a multistep process driven by the accumulation of carcinogen-induced genetic changes. Alterations of the 3p14 fragile site containing the fragile histidine triade gene and of the 9p21 tumor suppressor locus containing methylthioadenosine phosphorylase, p16 and p15 characteristically occur in oral leukoplakia, a known precursor of OSCC, and are at present considered to indicate the transition from simple keratosis (hyperplasia) to dysplasia. The aim of the study was to evaluate the occurrence of losses of 3p14 and 9p21 and to evaluate polysomies 3 and 9 in leukoplakias using highly sensitive fluorescence in situ hybridization (FISH) probes. Examining 67 leukoplakias (24 hyperplasias, 33 dysplasias, 10 in situ carcinomas), control tissues of oral mucosa from infants and adults as well as invasive carcinomas and normal epithelia of tumor patients with locus specific FISH probes targeting 3p14 and 9p21, and centromeric probes for chromosomes 3 and 9 we could demonstrate that losses of these sites appeared very early in the tumorigenesis of OSCC and were already present in the great majority of simple keratoses. Polysomy 3 occurring more frequently than polysomy 9 was characteristic of dysplasia and in situ carcinomas and thus seems to follow losses of 3p14 and 9p21 during oral squamous cell carcinogenesis.