FHIT and C-MYC expression in cervical histology and cytology as biomarkers for detecting high-grade intraepithelial neoplasia in human papillomavirus-positive women

BACKGROUND:

The current cervical cancer screening strategies based on Papanicolaou (Pap) and Human papillomavirus (HPV) tests receive great achievement but still exhibit many limitations in clinical practice. Exploring new biomarkers as stratified management method in HPV primary screening is becoming the tendency of current research.

METHODS:

Immunocytochemistry (ICC) of FHIT and C-MYC were performed on exfoliated cervical cells from 197 eligible high-risk HPV positive women. Mann-Whitney U test, Pearson Chi-Square test, logistic regression analysis and receiver operating characteristic (ROC) curves were used to assess the diagnostic efficiency.

RESULTS:

ICC staining intensity of FHIT and C-MYC in high-grade cervical intraepithelial neoplasia (CIN) specimens was significantly different from low-grade CIN and normal specimens. Compared with Pap test, ROC analysis of ICC in detecting high-grade CIN resulted in a larger area under the curve (AUC) (0.805 and 0.814 vs 0.723, p< 0.001). FHIT achieved higher sensitivity than Pap test (79.41% vs 66.67%, p= 0.04). Logistic regression analysis of the combination of two biomarkers led to higher AUC value, specificity and PPV than any single biomarker.

CONCLUSIONS:

The utility of FHIT and C-MYC ICC analysis in cervical exfoliated cells of HPV-positive women displayed superior diagnostic potential and may improve clinical performance of cervical cancer screening.

FHIT Oncosuppressor Gene Expression Profile in Human Anal Cancers

The FHIT gene, a member of the histidine triad gene family, is a tumor suppressor gene exhibiting deletions in the majority of human cancers. Aberrant transcripts of this gene have been found in about 50% of esophageal, stomach and colon carcinomas. Little is known about the molecular mechanisms involved in malignant transformation of the lining cells of the anus. In this study FHIT gene expression was investigated in this particular kind of human cancer. FHIT expression was comparatively analyzed at the mRNA level, by RT-PCR, in squamous anal cancers, normal anal tissue and peripheral blood samples. cDNA analyses showed variability in FHIT transcripts, without apparent effects on the predicted amino acid sequence. These different FHIT mRNAs could represent transcripts from an alternative splicing event. Our data indicate that the FHIT mRNA detected in anal cancers and in normal samples is heterogeneous. Immunohistochemical data suggest that the Fhit protein is expressed only in a fraction of the tumor cells, while it is strongly expressed in the epithelial cells of glands of the normal anal mucosa. The absence or poor expression of the Fhit protein in anal cancers suggests a role for this tumor suppressor gene product, as a risk factor, in the onset of this human cancer, as reported before for other human gastrointestinal tumors.

Fhit down-regulation is an early event in pancreatic carcinogenesis

Aberrant Fhit expression characterizes a large proportion of primary pancreatic ductal adenocarcinomas (PDACs), but fragmentary information is available on Fhit expression during the phenotypic changes of pancreatic ductal epithelium during multistep transformation. We assessed Fhit expression by immunohistochemistry in two different multistep pancreatic carcinogenic processes: pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasia (IPMN). We considered 105 surgically treated PDACs/IPMNs and selected 30 samples of non-neoplastic pancreatic parenchyma, 50 PanIN lesions, 30 IPMNs, 15 IPMNs with associated invasive carcinoma, and 60 adenocarcinomas. Normal pancreatic ducts and surrounding acinar cells consistently showed moderate to strong Fhit immunoreactivity. Significant down-regulation of Fhit expression was observed in association with increasing severity of dysplastia/neoplastia in both carcinogenic processes. This was further confirmed by studying multiple lesions obtained from the same surgical specimen. Of 60 PDACs, only 14 showed Fhit expression comparable to normal pancreatic ductal epithelium, while the remainder (77%) showed clearly negative or reduced Fhit expression. This study demonstrates that Fhit down-regulation is an early event in both multistep carcinogenic processes leading to PDAC.

[Research of Metachromatic Reaction of Saccharomyces cerevisiae]

This work is a continuation of research of the Chizhevsky-Velhover’s bio-astronomic effect. Monitoring of volutin granule metachromatic staining of Saccharomyces yeasts (S. cerevisiae UCM Y-517, S. cerevisiae CRY, S. cerevisiae CNX, S. bayanus UCM Y-493, S. unisporus UCM Y-2065, S. rosinii UCM Y-2614, S. exiguus UCM Y-649) under conditions of different space weather was carried out. S. cerevisiae UCM Y-517, which displayed the metachromatic reaction in 96.7 % cases, showed the biggest sensitivity to the space weather changes. The changes in phosphoric metabolism of S. cerevisiae CNX cells, which can not synthesize exopolyphosphatases PPX1 and PPN1 (CF 3.6.1.11), did not influence the metachromatic reaction. Yeast cells grown on wort-agar displayed more intensive metachromatic reaction compared to those grown on YEPD-agar. However, increasing concentration of phosphorus in YEPD-agar improved visualization of the metachromatic staining. The strain S. cerevisiae UCM Y-517 is recommended as a model for monitoring of volutin granules metachromatic reaction in the research project “Heliomed” because of its high sensitivity to the space weather changes.

Fhit Expression Protects Against HER2-Driven Breast tumor Development: Unraveling the Molecular Interconnections

The tumor suppressor gene FHIT is inactivated by genetic and epigenetic changes, i.e., loss of heterozygosity or promoter hypermethylation, in common human cancers. We recently showed that Fhit protein levels can be regulated by Fhit proteasome degradation mediated by EGF-dependent activation of EGFR family members, including HER2, whose overexpression is linked to poor prognosis in breast cancer. Analysis of a series of 384 human primary breast carcinomas revealed low/absent Fhit protein levels more frequently in HER2-overexpressing tumors. To test for a possible complementation of the FHIT and HER2 genes, tumor incidence was assessed in mice carrying one inactivated Fhit allele (Fhit(+/-)) crossed with FVB/N mice carrying the rat HER2/neu proto-oncogene driven by the mouse mammary tumor virus promoter. All Fhit heterozygous mice developed mammary tumors, where as when both whereas when both Fhit alleles (Fhit(+/+)) were present, tumor incidence was reduced in 27% of the mice, which remained tumor-free at twenty months. These tumor-free at twenty months twenty months. findings suggest a protective role for FHIT in HER2-driven mammary tumors. Together, these data argue for the cooperation between Fhit and HER2 in breast carcinogenesis.

FHIT suppresses epithelial-mesenchymal transition (EMT) and metastasis in lung cancer through modulation of microRNAs

Metastasis is the principal cause of cancer death and occurs through multiple, complex processes that involve the concerted action of many genes. A number of studies have indicated that the Fragile Histidine Triad (FHIT) gene product, FHIT, functions as a tumor suppressor in a variety of common human cancers. Although there are suggestions of a role for FHIT loss in progression of various cancers, a role for such loss in metastasis has not been defined. Here, via in vivo and in vitro assays, we reveal that the enforced expression of FHIT significantly suppresses metastasis, accompanied by inhibition of the epithelial-mesenchymal transition (EMT), a process involved in metastasis through coordinate modulation of EMT-related genes. Specifically, miR-30c, a FHIT-upregulated microRNA, contributes to FHIT function in suppression of EMT and metastasis by directly targeting metastasis genes Metadherin (MTDH), High-mobility group AT—hook 2 (HMGA2), and the mesenchymal markers, Vimentin (VIM) and Fibronectin (FN1), in human lung cancer. Finally, we demonstrate that the expression pattern of FHIT and miR-30c is inversely correlated with that of MTDH and HMGA2 in normal tissue, non-metastatic and metastatic tumors, serving as a potential biomarker for metastasis in lung cancer.

Although Fragile Histidine Triad (FHIT) is known as a potential tumor suppressor gene in terms of tumor initiation and progression, the role of FHIT in the metastatic process is not well characterized. Here it is shown that FHIT reduces the motility and invasiveness of lung cancer cells in vitro and ability to metastasize in vivo, at least partially through the miR-30c-mediated suppression of EMT, a critical process during tumor metastasis. This study provides new insights into the role of FHIT and a FHIT-activated miRNA, miR-30c, as crucial modulators in lung metastasis.

Expression of WWOX and FHIT is downregulated by exposure to arsenite in human uroepithelial cells

Ecological studies in Taiwan, Chile, Argentina, Bangladesh, and Mexico have confirmed significant dose-dependent associations between ingestion of arsenic-contaminated drinking water and the risk of various human malignancies. The FHIT and WWOX genes are active in common fragile sites FRA3B and FRA16D, respectively. Reduced expression of FHIT or WWOX is known to be an early indicator of carcinogen-induced cancers. However, the effect of arsenite on the expressions and molecular mechanisms of these markers is still unclear. The aims of this study were (i) to observe the expression of ATR, WWOX and FHIT proteins in urothelial carcinoma (UC) between endemic and non-endemic areas of blackfoot disease (BFD) by immunohistochemical analyses; (ii) to compare expression of these genes between arsenite-treated SV-HUC-1 human epithelial cells and rat uroepithelial cells; and (iii) to determine the role of DNMT and MEK inhibitors on expressions of WWOX and FHIT in response to arsenite in SV-HUC-1. The experiments revealed that expressions of ATR, WWOX and FHIT in UC significantly differed between BFD areas and non-BFD areas (p=0.003, 0.009 and 0.021, respectively). In fact, the results for the arsenite-treated groups showed that ATR, WWOX and FHIT are downregulated by arsenite in SV-HUC-1. However, the inhibitors suppressed the effects of arsenite on WWOX and FHIT proteins and mRNA expression. In conclusion, arsenite decreased expressions of ATR, WWOX and FHIT via ERK1/2 activation in SV-HUC-1 cells. These findings confirm that dysregulations of these markers may contribute to arsenite-induced carcinogenesis.

Association of the promoter methylation and protein expression of Fragile Histidine Triad (FHIT) gene with the progression of differentiated thyroid carcinoma

The role of aberrant methylation of fragile histidine triad (FHIT) promoters in the differentiated thyroid carcinoma (DTC) is not yet clear. Therefore, we investigated the association of the status of FHIT promoter methylation and FHIT protein expression with the clinicopathological progression of DTC, using PCR-based methylation assay and immunohistochemical technique. While no FHIT gene promoter methylation was observed in the matched non-cancerous epithelium (NCE) specimens, 24.6% of DTC samples demonstrated methylation in the FHIT promoter region. The protein expression of FHIT in NCE and DTC was 100.0% and 41.5% (P<0.01), respectively. There was a negative correlation between promoter methylation and protein expression of FHIT gene (P<0.05). Additionally, the methylation status appeared to be significantly associated with the pathological grade, tumor TNM stage, and lymph node metastasis (P<0.05), and FHIT proteins were weakly expressed in only about 20% of DTC with grade II pathological changes, TNM stage III/IV, or lymph node metastasis. Finally, the gender and tumor classification but not age marginally affected the promoter methylation and protein expression of FHIT. Our results suggest that methylation of the promoter region may play a key role in inactivation of FHIT - possibly leading to subsequent carcinogenesis and progression of DTC.

Fragile histidine triad (FHIT) gene is overexpressed in colorectal cancer

OBJECTIVE

FHIT gene, mapped at FRA3B site, encodes human diadenosine triphosphate hydrolase involved in the regulation of cell cycle and nucleotide metabolism. Decreased FHIT gene expression was previously observed in various types of human cancer, however, quantification of FHIT mRNA was seldom performed.

AIM

To investigate loss of heterozygosity (LOH) at FRA3B, expression of FHIT gene at the mRNA and protein levels in sporadic colorectal carcinoma (CRC) and benign colon adenoma.

MATERIALS AND METHODS

FHIT mRNA was quantified by the validated realtime PCR (QPCR) in tumor samples of 84 CRC patients and mucosal biopsies of 15 adenomas, in comparison to 37 control patients, whereas subgroup of 57 CRC, 10 adenoma and 10 control cases were selected for immunohistochemical (IHC) detection of the native FHIT protein and LOH determination at FRA3B.

RESULTS

Higher level of FHIT mRNA was found in 86% of CRC (P<0.001) and 60% of adenomas (P=0.016). IHC showed comparable results to QPCR (P=0.003), revealing the strongest presence of FHIT protein in Dukes' C/D stages (P<0.001) and N1/N2 lymph nodes metastasis in CRC (P=0.04). FHIT gene expression and Dukes' and G staging were positively correlated in CRC as analyzed by QPCR and IHC. Deletion analysis of the fragile FRA3B site revealed the highest LOH frequency at D3S1234 in 32.5% of CRC informative cases, however, LOH did not correspond to QPCR, IHC or clinical-pathological variables.

CONCLUSION

Our data suggest that reduction or absence of the FHIT gene expression is not a prerequisite for colorectal cancer development and progression.

Overexpression of the fragile histidine triad (FHIT) gene in inflammatory bowel disease

OBJECTIVE

FHIT gene encodes human diadenosine triphosphate hydrolase involved in the regulation of cell cycle and nucleotide metabolism and is a candidate tumor suppressor gene.

AIM

To investigate expression of FHIT gene at the mRNA and protein levels in sporadic inflammatory bowel disease (IBD).

MATERIALS AND METHODS

FHIT mRNA was quantified by the validated real-time PCR (QPCR) and FHIT protein was detected by immunohistochemistry (IHC) in mucosal biopsies of 139 ulcerative colitis (UC), 19 Crohn's disease (CD) and 37 control patients.

RESULTS

Significant FHIT gene overexpression was found in 78% of active UC but not in CD. IHC showed comparable results to QPCR.

CONCLUSION

The local up-regulation of FHIT gene and protein expression in active UC may represent an adequate response against inflammatory challenge of epithelial cell homeostasis and protect against DNA damage and cell cycle disturbances.

p53, p16 and Fhit proteins expressions in chronic esophagitis and Chagas disease

BACKGROUND

Models have suggested esophageal carcinogenesis can result from the alteration of sequences, leading to esophagitis, atrophy, dysplasia, carcinoma in situ and invasive carcinoma. While numerous genetic alterations have been reported in esophageal carcinogenesis, studies of benign lesions with precancerous potential are scarce.

MATERIALS AND METHODS

Immunohistochemistry was performed for p53, p16 and Fhit proteins in the esophageal mucosa from patients with Chagas disease (CD), chagasic megaesophagus (CM), chronic esophagitis (CE), esophageal squamous cell carcinoma (ESCC) and in normal mucosa (NM).

RESULTS

The proportion of p53-positive cases increased progressively according to the severity of the pathology CD (7.7%), CM (26.1%), CE (522%) and ESCC (100%). However, p16 and Fhit did not show any statistically significant differences among the groups.

CONCLUSION

p53 overexpression is involved in the initial steps of esophageal carcinogenesis, supporting further evaluation of its utility as a marker in precursor lesions, conversely, losses of Fhit and p16 expression may not be significant.

[Expression of nuclear factor-kappa-B/P65 and fragile histidine triad in colorectal carcinoma and clinical significance thereof]

OBJECTIVE

To investigate the expression of nuclear factor-kappa-B (NF-KB)/P65 and fragile histidine triad (FHIT) in colorectal carcinoma and clinical significance thereof.

METHODS

Immunohistochemistry (PV6000 method) was used to detect the expression of NF-kappaB/P65 and FHIT in 359 samples of colorectal carcinoma and 35 samples of normal mucosa at least 5 cm away from the carcinoma tissues. 198 of the patients were successfully followed up by telephone interview.

RESULTS

The positive expression rates of NF-kappaB/P65 and FHIT in the colorectal carcinoma were 67.7% (243/359) and 46.0% (165/359) respectively. NF-kappaB/P65 and FHIT were all related to the clinical stage, lymphatic invasion, and distant metastasis (all P < 0.05). The expression of FHIT was negatively correlated with invasion and differentiation degree (r = -0.285 and -0. 254 respectively, both P < 0.05). The 5-year survival rate of the patients with NF-kappaB/P65 expression was significantly lower than that of the patients negative in the NF-kappaB/P65 expression while the 5-year survival rate of the patients positive in FHIT expression was significantly higher than those negative in the FHIT expression (X2 = 23.25 and 51.13 respectively, both P < 0. 05). NF-kappaB/P65 expression in colorectal carcinoma was negatively correlated with the FHIT expression (r = -0.167, P = 0.019). The expression rate of NF-kappaB/P65 in carcinoma was significantly higher, but the expression rate of FHIT in carcinoma was significantly lower than those in normal mucosa tissues (X2 = 40.78 and 15.93 respectively, both P < 0.05). NF-kappaB/P65 was an independent prognostic indicator for disease-free survival and overall survival.

CONCLUSION

NF-KB/P65 and FHIT play significant roles in the generation and evolution of colorectal carcinoma and may be used as useful indicators for clinical assessment of tumor biological behavior and prognosis in patients with colorectal carcinoma.

Replication stress induces tumor-like microdeletions in FHIT/FRA3B

Common fragile sites (CFSs) are loci that preferentially exhibit metaphase chromosome gaps and breaks after partial inhibition of DNA synthesis. The fragile site FRA3B, which lies within the FHIT tumor-suppressor gene, is a site of frequent heterozygous and homozygous deletions in many cancer cells and precancerous lesions. The great majority of FHIT and other CFS-associated gene rearrangements in tumors are submicroscopic, intralocus deletions of hundreds of kilobases that often result in inactivation of associated genes. Although CFS instability leads to chromosome gaps and breaks and translocations, there has been no direct evidence showing that CFS instability or replication stress can generate large submicroscopic deletions of the type seen in cancer cells. Here, we have produced FHIT/FRA3B deletions closely resembling those in tumors by exposing human-mouse chromosome 3 somatic hybrid cells to aphidicolin-mediated replication stress. Clonal cell populations were analyzed for deletions by using PCR, array comparative genomic hybridization (aCGH), and FISH. Thirteen percent to 23% of clones exhibited submicroscopic FHIT deletions spanning approximately 200-600 kb within FRA3B. Chromosomes with FRA3B deletions exhibited significantly decreased fragility of this locus, with a 2- to 12-fold reduction in metaphase gaps and breaks compared with controls. Sequence analysis showed no regions of homology at breakpoints and suggests involvement of NHEJ in generating the deletions. Our results demonstrate that replication stress induces a remarkably high frequency of tumor-like microdeletions that reduce fragility at a CFS in cultured cells and suggests that similar conditions during tumor formation lead to intralocus deletion and inactivation of genes at CFSs and perhaps elsewhere in the genome.

Preclinical assessment of FHIT gene replacement therapy in human leukemia using a chimeric adenovirus, Ad5/F35

PURPOSE

Expression of the FHIT protein is lost or reduced in most solid tumors and a significant fraction of hematopoietic malignancies. Adenovirus 5 (Ad5) virus or adeno-associated viral vectors have been used to study the tumor suppressor function of FHIT in solid tumors, but these tools have not been effective in leukemias. We have generated a chimeric FHIT-containing adenovirus composed of Ad5 and the group B adenovirus called F35 with which we have been able to efficiently infect hematopoietic cells.

EXPERIMENTAL DESIGN

Infection efficiency of Ad5/F35-FHIT and Ad5/F35-GFP viruses was tested in leukemia cell lines that lacked FHIT expression, and biological effects of successful infection were assessed. An acute myelogenous leukemia, a chronic myelogenous leukemia, and four acute lymphoblastic leukemia human cell lines were examined as well as two EBV-transformed B lymphoblastoid cell lines that expressed endogenous FHIT.

RESULTS

Two of four acute lymphoblastic leukemia cell lines, Jurkat and MV4;11, which were efficiently infected with Ad5/F35-FHIT, underwent growth suppression and massive induction of apoptosis without apparent activation of caspase-8 or caspase-2 and late activation of caspase-3. Treatment of infected cells with caspase-9 and caspase-3 inhibitors partially blocked FHIT-induced apoptosis. The two remaining infected acute lymphoblastic leukemia cell lines, Molt-3 and RS4;11, were apparently unaffected. Restoration of FHIT expression in the chronic myelogenous leukemia K562 cell line and the acute myelogenous leukemia KG1a cell line also induced apoptosis but at later time points than seen in the acute lymphoblastic leukemia Jurkat and MV4;11 cell lines. I.v. injection of Ad5/F35-FHIT-infected Jurkat cells resulted in abrogation of tumorigenicity in the NOD/SCID xenogeneic engraftment model.

CONCLUSION

FHIT restoration in some FHIT-deficient leukemia cells induces both antiproliferative and proapoptotic effects involving the intrinsic caspase apoptotic pathway.

Kinetic and mutational analyses of the major cytosolic exopolyphosphatase from Saccharomyces cerevisiae

Yeast exopolyphosphatase (scPPX) processively splits off the terminal phosphate group from linear polyphosphates longer than pyrophosphate. scPPX belongs to the DHH phosphoesterase superfamily and is evolutionarily close to the well characterized family II pyrophosphatase (PPase). Here, we used steady-state kinetic and binding measurements to elucidate the metal cofactor requirement for scPPX catalysis over the pH range 4.2-9.5. A single tight binding site for Mg(2+) (K(d) of 24 microm) was detected by equilibrium dialysis. Steady-state kinetic analysis of tripolyphosphate hydrolysis revealed a second site that binds Mg(2+) in the millimolar range and modulates substrate binding. This step requires two protonated and two deprotonated enzyme groups with pK(a) values of 5.0-5.3 and 7.6-8.2, respectively. The catalytic step requiring two deprotonated groups (pK(a) of 4.6 and 5.6) is modulated by ionization of a third group (pK(a) of 8.7). Conservative mutations of Asp(127), His(148), His(149) (conserved in scPPX and PPase), and Asn(35) (His in PPase) reduced activity by a factor of 600-5000. N35H and D127E substitutions reduced the Mg(2+) affinity of the tight binding site by 25-60-fold. Contrary to expectations, the N35H variant was unable to hydrolyze pyrophosphate, but markedly altered metal cofactor specificity, displaying higher catalytic activity with Co(2+) bound to the weak binding site versus the Mg(2+)- or Mn(2+)-bound enzyme. These results provide an initial step toward understanding the dynamics of scPPX catalysis and reveal significant functional differences between structurally similar scPPX and family II PPase.

Expression of PTEN and FHIT is involved in regulating the balance between apoptosis and proliferation in lung carcinomas

BACKGROUND

The lung carcinoma is a major cause of cancer-related death, but molecular aspects of its genesis and progression remain unclear. The present study aimed to clarify the roles of FHIT and PTEN expression.

MATERIALS AND METHODS

Expression of FHIT and PTEN was examined using tissue microarrays (TMAs) of lung carcinoma (n = 155) and normal lung samples (n =40) by immunohistochemistry and compared with clinicopathological parameters of tumors, including expression of CPP32 and Ki-67, as well as survival time of patients.

RESULTS

PTEN was positively expressed in the nuclei of stratified squamous and alveolar epithelial cells, and FHIT in the cytoplasm of stratified squamous and type II alveolar epithelial cells. Both were more frequently expressed in normal lung tissues than lung carcinomas (p<0.05). Immunohistochemically, PTEN expression gradually decreased from small cell carcinomas (SCCs), through large cell carcinomas (LCCs) and adenocarcinomas (ADs) to squamous (SQ) cell carcinomas (p <0.05), whereas FHIT was more highly expressed in ADs and LCCs, compared with SQs and SCCs (p <0.05). PTEN expression was negatively linked to lymphatic and venous invasion of tumors (p<0.05), but positively to CPP32 expression (p<O0.05). FHIT expression was higher in females than males (p<0.05), and negatively related to Ki-67 expression (p<0.05). Kaplan-Merier analysis indicated that expression of PTEN, but not FHIT, was positively correlated with a high cumulative survival rate for patients with lung carcinomas even after stratified analysis of the histological classification (p<0.05).

CONCLUSION

PTEN and FHIT may contribute to regulation of the balance between apoptosis and proliferation in physiological events in normal lung and during development of lung carcinoma. Down-regulated PTEN appears closely linked to frequent lymphoangiogenic invasion and low FHIT expression, and could provide a molecular basis for differences in genetic sensitivity between men and women to lung carcinogens. PTEN could be a good prognostic factor for lung carcinomas, regardless of the histological types.

The expression of FHIT, PCNA and EGFR in benign and malignant breast lesions

Immunohistochemical staining for FHIT and PCNA proteins was carried out in 451 breast lesions showing nonproliferative benign breast disease (BBD) (n=263), proliferative BBD without atypia (n=128), proliferative BBD with atypia (n=11), carcinoma in situ (n=15) or invasive carcinoma (n=34) and for EGFR protein in a subset of 71 of these cases. FHIT underexpression was not detected in nonproliferative lesions, but occurred in 2% of proliferative BBD without atypia, 10% proliferative BBD with atypia, 27% of carcinoma in situ and 41% of invasive carcinoma, which suggests that it could be useful in assessing those carcinoma in situ lesions (ductal, DCIS and lobular, LCIS) that are more likely to progress to malignancy. Preliminary microarray comparisons on DCIS and invasive carcinoma samples dissected from formalin-fixed paraffin sections showed a consistent downregulation of two previously identified FHIT-related genes, caspase 1 and BRCA1 in lesions underexpressing FHIT.

Abnormal fragile histidine triad (Fhit) expression in invasive cervical adenocarcinoma: association with tumor aggressiveness

The fragile histidine triad (FHIT) gene is a candidate tumor suppressor gene. Aberrant expression of the encoded protein and inactivation of FHIT correlate with several clinicopathological parameters in various tumor types, including cervical cancer, but Fhit expression has rarely been studied in cervical adenocarcinoma. We assessed Fhit protein expression in 35 surgical specimens of invasive adenocarcinomas of the uterine cervix and investigated whether expression alteration on immunohistochemistry staining is associated with important clinicopathological features. Considerably reduced or absent Fhit staining was observed in 11 cancers (31.4%). By univariate analysis, Fhit protein expression was significantly associated with nodal status (P = .002), histologic grade (P = .000), and International Federation of Gynecology and Obstetrics stage (P = .032). Depth of invasion, tumor size, or parametrial invasion did not show important association with Fhit. Lymph node status, International Federation of Gynecology and Obstetrics stage, and histologic grade are known prognostic factors of cervical adenocarcinoma, and Fhit status on immunohistochemistry staining demonstrated significant association with tumor aggressiveness. Staining of biopsy specimens for Fhit is worthy of study as a prognostic tool.

Characterization of the Mn2+-stimulated (di)adenosine polyphosphate hydrolase encoded by the Deinococcus radiodurans DR2356 nudix gene

The DR2356 nudix hydrolase gene from Deinococcus radiodurans has been cloned and the product expressed as an 18 kDa histidine-tagged protein. The enzyme hydrolysed adenosine and diadenosine polyphosphates, always generating ATP as one of the initial products. ATP and other (deoxy)nucleoside triphosphates were also substrates, yielding (d)NDP and Pi as products. The DR2356 protein was most active at pH 8.6-9.0 and showed a strong preference for Mn(2+) as activating cation. Mg(2+) ions at 15 mM supported only 5% of the activity achieved with 2 mM Mn(2+). K (m) and k (cat) values for diadenosine tetra-, penta- and hexaphosphates were 2.0, 2.4 and 1.1 microM and 11.4, 28.6 and 12.0 s(-1), respectively, while for GTP they were 20.3 microM and 1.8 s(-1), respectively. The K (m )for adenosine 5'-pentaphosphate was <1 microM. Expression analysis showed the DR2356 gene to be induced eight- to ninefold in stationary phase and in cells subjected to slow dehydration plus rehydration. Superoxide (but not peroxide) treatment and rapid dehydration caused a two-to threefold induction. The Mn-requirement and induction in stationary phase suggest that DR2356 may have a specific role in maintenance mode metabolism in stationary phase as Mn(2+) accumulates.

Coexpression of Fragile Histidine Triad and c-kit Is Relevant for Prediction of Survival in Patients with Small Cell Lung Cancer

BACKGROUND

In a retrospective analysis of 195 patients with small cell lung cancer (SCLC), we examined the prognostic value of a coexpression of fragile histidine triad (FHIT) protein and c-kit on patient's survival.

METHODS

As assessed by immunohistochemistry using formalin-fixed, paraffin-embedded tissue sections, tumors of 195 patients with SCLC were evaluated for FHIT and c-kit coexpression.

RESULTS

Coexpression of FHIT and c-kit was observed in 53.3%; a positive expression of either FHIT or c-kit was found in 40.5%. Complete lack of FHIT and c-kit (6.2%) was associated with a significantly shorter survival time for the patients with a mean of 122 +/- 45 days compared with 468 +/- 89 days for patients with lung cancer coexpressing FHIT and c-kit (P = 0.0011). The proportion of FHIT- and c-kit-positive cells within a tumor was also related to survival time. Patients with tumors with a proportion between 0% to 25% of FHIT- and c-kit-positive cells had the worst survival of 157 +/- 34 days compared with 496 +/- 95 days for patients showing >25% FHIT- and c-kit-positive cells (P = 0.0002). Further, variables associated with shorter survival times were low performance status, elevated lactate dehydrogenase level, and advanced tumor stage according to tumor-node-metastasis classification. Multivariate analysis using Cox regression model, including 11 variables, confirmed the prognostic significance of a combined expression of FHIT and c-kit next to tumor stage, performance status, and lactate dehydrogenase level.

CONCLUSIONS

Differential FHIT and c-kit expression was of prognostic relevance for survival in patients with SCLC and therefore provide useful variables for therapeutic decisions.

[Expression of the genes FHIT, Bcl-2 and Bax in breast infiltrating ductal carcinoma and clinicopathological significance thereof]

OBJECTIVE

To investigate the expression of the genes fragile histidine triad (FHIT), Bcl-2, and Bax, biological markers of breast infiltrating ductal carcinoma in this carcinoma and clinicopathological significance thereof.

METHODS

The clinical data of 100 patients with breast infiltrating ductal carcinoma, all females, aged 435 (28 - 92), were collected. Immunohistochemistry was used to detect the protein expression of FHIT, Bcl-2 and Bax in the carcinoma tissues resected during operation.

RESULTS

The protein expression rates of FHIT, Bcl-2 and Bax in the tumor tissues were 73%, 50%, and 34% respectively. The disease free survival (DFS) and overall survival (OS) of the FHIT positive patients were 81.8 months and 123.6 months, both significantly longer than those of the FHIT-negative patients (27.7 months and 74 months, both P < 0.05). The DFS of the Bcl-2-positive patients was 83 months, significantly longer than that of the Bcl-2-negative patients (45 months, P < 0.05). The mean DFS of the Bcl-2-positive patients who received postoperative adjuvant chemotherapy was 54.8 months, significantly longer than that of the Bcl-2-negative patients who received postoperative adjuvant chemotherapy (41.6 months). The mean DFS and OS of the Bcl-2-negative patients receiving CAF regimen were 55 months and 58.8 months respectively, both longer than those of the Bcl-2-negative patients receiving other regimens (27 months and 36 months respectively). However, the expression of Bax failed to show correlation with the prognosis of breast infiltrating ductal carcinoma.

CONCLUSION

Expression of FHIT and expression of Bcl-2 are positively correlated to the DFS and OS of the breast infiltrating ductal carcinoma. Bax is not predictive to the prognosis of breast infiltrating ductal carcinoma.

Fhit protein is preferentially expressed in the nucleus of monocyte-derived cells and its possible biological significance

The FHIT gene encompassing the most active common human fragile region, FRA3B, has been proposed as a tumour suppressor gene for important common human carcinomas. The mechanism in which Fhit protein exerts its tumour suppressor activity is still obscure. To further understand the Fhit function associated with its intracellular localization we have investigated its cellular localization and distribution in human normal and cancerous tissues. Data of 1500 samples from immunohistochemistry showed that Fhit protein was preferentially and stably expressed in the nucleus of monocyte-derived or histiocytic lineage cells including monocytes of the circulating blood cells, macrophages of the connective tissue, Kupffer cells of the liver, alveolar macrophages or dust cells of the lung, osteoclasts of bone, microglia of the brain, epithelioid cells under chronic inflammatory conditions, foreign-body giant cells, Langerhans cells of the epidermis and dendritic cells of various kinds of human tissue, although the protein could also be infrequently observed in the nucleus of some quiescent epithelial cells. In active cells other than histiocytes, Fhit protein was detected either in cytoplasm or was negative. Neurons expressed Fhit strongly and neuroglial cells did so moderately but only in the cytoplasm. There was no Fhit protein detected in the neutrophils, lymphocytes, plasma cells and lipocytes. The present data showes that the stable nuclear localization of Fhit is not only a special marker for histiocytes with various morphologies but also may suggest the other function concerning Fhit as a signaling molecule related to anti-proliferation function. The detailed biological function related to nuclear localization of Fhit protein in the histiocytes remains to be further studied.

Early loss of Fhit in the respiratory tract of rodents exposed to environmental cigarette smoke

The Fhit gene, encompassing the most active common human chromosomal fragile region, FRA3B, has been shown to act as a tumor suppressor. Several studies have shown significant Fhit alterations or Fhit protein loss in lung cancers from smokers compared with lung cancers from nonsmokers. To evaluate the role of Fhit under controlled experimental conditions, we exposed rodents to environmental cigarette smoke (ECS) and evaluated Fhit expression or Fhit protein in the respiratory tract. After 14 days of exposure to ECS, loss of Fhit protein in the bronchial/bronchiolar epithelium affected half of the tested B6-129(F(1)) mice, either wild type or Fhit(+/-). After 28 days, it affected the vast majority of the tested SKH-1 hairless mice and of A/J mice and all (UL53-3 x A/J)F(1) mice, either wild type or P53(+/-). In Sprague-Dawley rats, exposure to ECS for up to 30 days caused a time-dependent loss of Fhit in pulmonary alveolar macrophages. Moreover, ECS down-regulated Fhit expression and significantly decreased Fhit protein in the rat bronchial epithelium. The oral administration of N-acetylcysteine attenuated the ECS-related loss of Fhit, whereas oltipraz, 5,6-benzoflavone, phenethyl isothiocyanate, and indole 3-carbinol, and their combinations had no significant effect. Parallel studies evaluated a variety of molecular, biochemical, and cytogenetic alterations in the respiratory tract of the same animals. In conclusion, there is unequivocal evidence that Fhit is an early, critical target in smoke-related lung carcinogenesis in rodents, and that certain chemopreventive agents can attenuate the occurrence of this gene alteration.

Expression of FHIT in esophageal epithelium and carcinoma: reference to drinking, smoking and multicentric carcinogenesis

BACKGROUND

Both alcohol consumption and cigarette smoking are risk factors for esophageal cancer. The purpose of this study was to clarify whether the fragile histidine triad (FHIT) is their target gene in esophageal carcinogenesis as well as in multicentric carcinogenesis.

PATIENTS AND METHODS

The expression of FHIT was immunohistochemically examined in the squamous cell carcinoma as well as in the normal esophageal epithelium of 55 cases with esophageal cancer.

RESULTS

The median drinking indices (DIs) were 546 and 1092 (p<0.01) in cases with positive FHIT expression and those with a diminished expression in the esophageal epithelium, respectively. Furthermore, the incidences of intra-esophageal multiple cancer were 44% and 13%, respectively (p<0.05). Regarding the expression in cancer lesions, the median DIs were 280 and 721 in positive and diminished cases, respectively (p=0.081).

CONCLUSION

A loss of FHIT expression is associated not only with alcohol-induced esophageal carcinogenesis, but also with multicentric carcinogenesis.

FHIT is up-regulated by inflammatory stimuli and inhibits prostaglandin E2-mediated cancer progression

The FHIT gene is known to be susceptible to environmental carcinogens. Formation of prostaglandin E(2) (PGE(2)) is catalyzed by cyclooxygenase-2 (COX-2) and may influence malignant phenotype in colorectal cancer. We explored whether FHIT might play a role in progression of colorectal cancer through inflammation-associated PGE(2) activity. Immunohistochemical study of COX-2 and FHIT expression was done in 92 colorectal cancer tumors. We also used a FHIT-expressing cancer cell line (H460) induced by ponasterone A and two FHIT small interfering RNA-treated colorectal cancer cell lines (CCK81 and DLD1). After PGE(2) stimulation, we compared synthesis of PGE(2) (ELISA assay) and cell proliferation [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay]. Immunohistochemistry showed a significant association between COX-2 and FHIT expression in colorectal cancers (P < 0.01). In a subset of 41 COX-2-expressing tumors, 12 FHIT(-) tumors showed deeper cancer invasion than 29 FHIT(+) tumors (P < 0.01). Experimental study, however, showed there was no direct interaction between FHIT and COX-2. Considered with results from another experiment with epidermal growth factor receptor (EGFR), we hypothesize that FHIT and COX-2 might be regulated by a common molecule, such as EGFR. Additionally, there was an inverse and direct correlation between PGE(2) synthesis and FHIT in vitro, suggesting that FHIT's postulated antiaggressive effect on tumor goes through PGE(2) but not COX-2. Loss of FHIT expression in colorectal cancer suggests higher malignant potential. We conclude that FHIT suppressed cancer cell proliferation in this malignancy by directly inhibiting synthesis of PGE(2) but not affecting that of COX-2.

FHIT protein enhances paclitaxel-induced apoptosis in lung cancer cells

The fragile histidine triad (FHIT) gene is a frequent target of deletions in lung cancer. Previous studies have shown that FHIT gene transfer into lung cancer cells lacking FHIT expression results in induction of apoptosis. However, the effect of FHIT expression on apoptosis induced by chemotherapeutic agents and its intracellular mechanism is poorly understood. This study was undertaken to elucidate the effect of FHIT expression and the role of Bcl-2-caspase signaling in paclitaxel-induced apoptosis in lung cancer cells. NCI-H358 lung cancer cells, which lack FHIT expression, were stably transfected with plasmid vector containing FLAG-tagged wildtype FHIT. We investigated effects of paclitaxel on apoptosis, activation of caspase system and expression of Bcl-2 family. We next evaluated whether these effects were reversed by blocking FHIT expression using siRNA. Paclitaxel enhanced apoptosis in FHIT-expressing cells compared to that in control vector-transfected cells, and this enhancement was suppressed by siRNA treatment. Activities of caspase-3 and caspase-7, but not of caspase-8, were higher in FHIT-expressing cells than in control vector-transfected cells, and this was reduced by siRNA treatment. When caspase activation was blocked by a pan-caspase inhibitor in FHIT-expressing cells, paclitaxel-induced apoptotic cell death was decreased similar to that in control vector-transfected cells. Bcl-2 and Bcl-xL expressions were down-regulated after paclitaxel treatment in FHIT-expressing cells, whereas Bax and Bad expressions were up-regulated. These were reversed by siRNA treatment. These results indicate that paclitaxel-induced apoptosis enhanced by FHIT expression in lung cancer cells might be associated with modulation of Bcl-2-caspase signaling.

[Relationship between the expression of fragile histidine (FHIT) and the development of vulvar carcinoma]

OBJECTIVE

To explore the relationship between the reduction of FHIT expression of fragile histidine (FHIT) and the development of vulvar carcinoma.

METHODS

The expression of the FHIT product was detected by immunochemistry in the tissue samples of 20 normal vulvas, 22 vulvar intraepithelial neoplasias (VINs), and 60 primary vulvar carcinomas.

RESULTS

The expressive rates of FHIT protein in the squamous epithelium of normal vulvas, VIN I - II, VIN II, and noninvasive and invasive vulvar carcinoma were 100% (20/20), 72.7% (8/11), 45.5% (5/11), and 21.7% (13/60) respectively (P<0.05). The expressive rates of FHIT protein in the well differentiated, intermediately differentiated and poorly differentiated invasive vulav carcinoma were 60.0% (9/15), 20.0% (3/15), and 3.3% (1/30) respectively (P<0.05). The expressive rate of the impaired FHIT protein in the invasive vulva carcinoma with lymphnode metastasis (10%) was lower than that without lymphnode metastasis (27.5%).

CONCLUSION

Abnormal FHIT expression may play an important role in the progression of vulvar carcinoma. The expression of FHIT may provide important information for the prognosis of vulva carcinoma.

FHIT expression in neoplastic, hyperplastic, and normal endometrium

Fragile histidine triad (FHIT), a candidate of tumor suppressor protein, expression was examined on paraffin-embedded specimens in proliferative, secretory, hyperplastic, and neoplastic human endometrium by immunohistochemistry. The results of FHIT immunoreactivity in endometrial carcinomas were compared with prognostic indicators as well as with p53 overexpression. Forty-four cases of endometrial carcinoma, 30 normal functional (15 proliferative, 15 secretory), and 24 hyperplastic endometrium (12 without atypia, 12 with atypia) specimens were studied using polyclonal FHIT antibody. The streptavidin-biotin-peroxidase detection system was used, and the intensity and the distribution of immunoreactivity were evaluated semiquantitatively. There were no significant differences in FHIT expression in the proliferative, secretory, hyperplastic, either with or without atypia, or carcinomatous endometria. No significant difference in FHIT expression of endometrial carcinomas was detected when prognostic parameters or p53 overexpression were considered. Loss or reduced FHIT expression was not found to predict disease-free or cumulative survivals. This study showed that loss or reduction in FHIT protein expression is present in normal functional and hyperplastic endometria as well as in neoplastic endometrium. FHIT protein seems not to be involved directly in endometrial carcinogenesis, but rather, it regulates cell proliferation both in physiologic and in pathologic conditions of endometrium.

Concordant loss of fragile gene expression early in breast cancer development

The FHIT and WWOX genes encompass the FRA3B and FRA16D fragile sites at chromosomes 3p14.2 and 16q23.3, respectively. Reduced Fhit and Wwox expression has been reported in approximately two-thirds of invasive breast tumors. Expression of these fragile gene products, as well as ErbB2 and p53, were evaluated immunohistochemically in 44 pure and 31 adjacent-to-invasive ductal carcinoma in-situ (DCIS) cases. Reduced Fhit and Wwox expression were observed in (i) 70% and 68% of pure DCIS; (ii) 52% and 55% of DCIS adjacent-to-invasive tumor cases; and (iii) 20% and 50% of adjacent normal tissue in pure DCIS cases. Reduced Wwox expression in adjacent normal tissue was observed in 30% of cases in the DCIS adjacent-to-invasive group. Reduced Fhit and Wwox expression was observed in 61% of adjoining invasive tumors. In all normal, pure DCIS, and DCIS adjacent-to-invasive lesions, Fhit and Wwox expression was positively associated (P = 0.034, P = 0.042, P = 0.004, respectively) and in the invasive component there was a positive trend toward association (P = 0.075). Fhit and Wwox were more frequently reduced in high-grade lesions in the DCIS adjacent-to-invasive (P = 0.025, P = 0.004, respectively). In the pure DCIS group, there was a statistically significant negative association between Fhit and ErbB2 expression in DCIS (P = 0.035). In summary, reduced Fhit and Wwox expression in in-situ breast cancer was associated, which may contribute to the high-grade DCIS-invasive tumor pathway.

[Expressions of FHIT and cyclin D1/CDK4 in oral cancer and oral precancerous lesions]

OBJECTIVE

To detect the expressions of fragile histidine triad (FHIT) and cyclin D1/CDK4 in oral squamous cell carcinoma (OSCC) and oral precancerous lesions and investigate the relationship between the expressions and the histopathological changes.

METHODS

Immunohistochemical staining by SP methods was utilized to detect the expression of FHIT and cyclin D1/CDK4 in 64 cases of OSCC, 39 oral precancerous lesions and 12 normal oral mucosa specimens.

RESULTS

The rate of the negative or low FHIT expression in OSCC was 17% (11/64), which was remarkably lower than that in normal oral membrane and oral precancerous lesions (P<0.01). Significantly higher levels of cyclin D1/CDK4 expressed in OSCC than in normal oral membrane and precancerous lesions (P<0.01). There was no significant correlation between FHIT and cyclin D1/CDK4, and positive correlation between cyclin D1 and CDK4 was observed.

CONCLUSION

FHIT, cyclin D1 and CDK4 may play a role in the pathogenesis of OSCC, and FHIT can down-regulate the expression of cyclin D1.

[Study on the relationship between LOH and MI of FHIT gene and the development of cervical carcinoma]

OBJECTIVE

To explore the relationship of loss of heterozygosity (LOH) and microsatellite instability (MI) of fragile histidine triad (FHIT) gene to the development of cervical carcinoma.

METHODS

Two sites of microsatellite polymophism in FHIT gene were selected to detect LOH and MI in 60 cases of primary invasive cervical carcinoma and 35 cases of cervical intra-epithelial neoplasia (CIN).

RESULTS

At D3S1234 and D3S1300, the LOH rates of primary invasive cervical carcinomas were 45.0% (27/60) and 38.3% (23/60), the MI rates were 18.3% (11/60) and 11.7% (7/60), respectively. The LOH rates of CINs were 42.9% (15/35) and 37.1% (13/35), the MI rates were 11.4% (4/35), 8.6% (3/35), respectively. There were no significant differences between invasive cervical carcinomas and CINs in respect to their positive rates of LOH and MI at D3S1234 and D3S1300 (P>0.05). There were significant differences in LOH rates at D3S1234 and D3S1300 between the well/moderately differentiated cervical carcinomas and the poorly differentiated invasive cervical carcinomas (P<0.05). Significant differences were noted between the invasive cervical carcinomas with lymph node metastasis and those without lymph node metastasis in regard to their LOH and MI at the two sites (P < 0.05). The positive rates of LOH and MI for CIN III and noninvasive cervical carcinomas were higher than those for CIN I-II.

CONCLUSION

The FHIT gene change is a relatively late event in CINs. The detection of the LOH of FHIT gene might be helpful to the early diagnosis and the screening of cervical carcinoma. It might also be useful for predicting the prognosis of cervical carcinoma.

[Expression and significance of fragile histidine triad in oral cancer and precancerous lesions]

OBJECTIVE

To detect the expression of fragile histidine triad (FHIT) in oral cancer and oral precancerous lesions and investigate the relationship between the FHIT expression and the histopathological changes.

METHODS

Immunohistochemical staining by SP methods was utilized to detect the expression of FHIT in 64 cases of oral squamous cell carcinoma, 39 oral precancerous lesions and 12 normal oral mucosa specimens.

RESULTS

The positivity rate of FHIT in normal oral membrane was 100% (12/12), and medium and high FHIT expression levels were detected in oral precancerous lesions but without significant difference from that in normal oral mucosa. In 64 oral squamous cell carcinoma specimens, 3 were negative for FHIT expression, 8 had low expression, and the other 43 had moderate and high expression. The rate of negative or low FHIT expression in the oral squamous cell carcinoma was 17% (11/64), which was significantly different from that in the normal oral mucosa and oral precancerous lesions, but the rate was not correlated to the differentiation of the cancer.

CONCLUSION

The tumor suppressor gene FHIT plays a role in the pathogenesis of oral squamous cell carcinoma.

Components of DNA Damage Checkpoint Pathway Regulate UV Exposure–Dependent Alterations of Gene Expression of FHIT and WWOX at Chromosome Fragile Sites

Common chromosome fragile sites are highly recombinogenic and susceptible to deletions during the development of environmental carcinogen-induced epithelial tumors. Previous studies showed that not only genetic but also epigenetic alterations in cancerous cells are involved in inactivation of the genes FHIT and WWOX at chromosome fragile sites, reported to be potential tumor suppressor genes. Here we investigated the effect of UV light on the gene expression. After exposure to UV, the mRNA and protein of the two genes in murine embryonic fibroblasts (MEF) were unstable, apparently at the G1-S phase of the cell cycle, which was consistent with nuclear run-on assay. A study of MEFs synchronized via a double thymidine block indicated that, after the exposure, the expression of Fhit and Wwox was reduced in E2f-1-deficient cells and markedly in wild-type cells, whereas the reduction was partially inhibited in Trp53-deficient cells; cells at the S phase seemed to be sensitive to exogenous FHIT, suggesting a role of the checkpoint at the G1-S phase in the stability of gene expression and a possible involvement of FHIT function at the S phase. The transfection experiment showed that the UV-induced decrease in expression was partially inhibited by transfection of kinase-dead Atr (ataxia telangiectasia mutated and Rad3 related), which is a sensor of UV-induced damage. Taken together, the present study showed that UV-induced alterations of the fragile site gene expression are involved at least partially in the checkpoint function, suggesting the role in the process of carcinogenesis after exposure to UV.

[Methylation of promoter and expression of FHIT gene in laryngeal squamous cell carcinoma]

OBJECTIVE

To study the relationship between status of methylation of FHIT gene promoter and expression of its protein in laryngeal squamous cell carcinoma (LSCC).

METHOD

PCR-based restriction enzyme assay and immunohistochemical SP technique were used to detect the status of methylation of FHIT gene promoter and expression of its protein in 41 cases of LSCC and their matched normal squamous epithelium (NSE).

RESULT

In NSE, there was no promoter methylation of FHIT gene, while in LSCC the rate of it was 24.4% (10/41), and it was related to the tumor pathological grade and lymph node metastasis (P < 0.01). The positive rate of FHIT expression in NSE and LSCC was 100.0% (41/41) and 46.3% (19/41) respectively, and the expression of FHIT was related to the tumor TNM stage and lymph node metastasis (P < 0.05). There was significant correlation between methylation of FHIT gene promoter and expression of its protein (P < 0.01).

CONCLUSION

Methylation of promoter might be one of important factors of inactivation of FHIT gene, and might play important role in carcinogenesis and progression of LSCC.

[Correlation between methylation of 5'-CpG islands and inactivation of FHIT gene in cervical cancer]

BACKGROUND & OBJECTIVE

Fragile histidine triad (FHIT) gene, a tumor suppressor gene, correlates with tumorigenesis of many solid tumors, and may be inactivated via methylation. This study was designed to explore relationship of methylation of 5'-CpG islands with inactivation of FHIT gene in cervical cancer.

METHODS

Methylation of 5'-CpG islands in 10 normal cervical squamous epithelial tissues, and 40 cervical cancer tissues was detected with methylation specific polymerase chain reaction (MSP), protein expression of FHIT was detected with immunohistochemistry, and their correlations with clinicopathologic features of cervical cancer were statistically analyzed.

RESULTS

(1) The 5'-CpG islands methylation rate of FHIT gene in cervical cancer tissues was 40.0% (16/40), while no methylation of FHIT gene was found in normal cervical tissues. (2) The methylation rates of FHIT gene in cervical cancer of stage I was 14.3% (2/14), significantly lower than that in cervical cancer of stage II (56.5%, 13/23) (P<0.05). (3) Expression of FHIT protein in cervical cancer was 33.0% (12/40), significantly lower than that in normal cervical tissue (100%, 10/10) (P<0.05).

CONCLUSION

The 5'-CpG islands methylation may play an important role in inactivation of FHIT gene, and may be related with tumorigenesis of cervical cancer.

[Expressions of PTEN and FHIT in oral squamous cell carcinoma and their relations with cyclin D1]

OBJECTIVE

To study the expressions of PTEN, FHIT and cyclin D1 in normal oral mucosa and oral squamous cell carcinoma (OSCC), and analyze the relationship between PTEN/FHIT and cyclin D1.

METHODS

Immunohistochemical staining with SP methods was used to detect the expression of PTEN, FHIT and cyclin D1 in OSCC tissues in 62 cases and normal oral mucosa in 12 cases.

RESULTS

The positivity rates of PTEN and FHIT were both 100% (12/12) in the normal oral mucosa, while in 62 cases of OSCC, 24.2% (15/62) and 17.7% (11/62) were negative for (or with low expression of) PTEN and FHIT, respectively. In normal oral mucosa, 91.7% (11/12) cases had negative or low cyclin D1 expression, while 53.2% (33/62) of the OSCC cases were positive for cyclin D1 expression. In all the cases, when PTEN and FHIT were strongly expressed, 37.8% (28/74) of the cases had negative or low expression of cyclin D1, including 11 normal cases.

CONCLUSION

The tumor suppressor genes PTEN and FHIT play a role in the pathogenesis of OSCC, and PTEN and FHIT can down-regulate the expression of cyclin D1.

Prognostic relevance of fragile histidine triad protein expression in patients with small cell lung cancer

PURPOSE

The fragile histidine triad protein (FHIT) is a putative tumor suppressor in patients with lung cancer. In this study, we examined the prognostic value of FHIT expression for survival in patients with small cell lung cancer (SCLC).

EXPERIMENTAL DESIGN

As assessed by immunohistochemistry using formalin-fixed, paraffin-embedded tissue sections, tumors of 225 patients with SCLC were retrospectively evaluated for FHIT expression. The influence of FHIT staining intensities as well as the proportion of FHIT-positive cells within a tumor was taken into consideration for univariate and multivariate survival analysis.

RESULTS

FHIT expression was observed in 61.8% of the SCLC tumors. Lack of FHIT was significantly associated with a shorter survival time for the patients with a median of 157 +/- 18 days compared with 210 +/- 18 days for those patients with FHIT-positive tumors (P = 0.0061). Furthermore, the proportion of FHIT-positive cells within the tumor was related to survival. Patients with tumors of <25% FHIT-positive cells had the worst survival of 155 +/- 21 days compared with 217 +/- 19 days for patients with a proportion of > or =25% of FHIT-expressing tumor cells (P = 0.0016). In contrast to the proportion of FHIT-positive cells within the tumor, no significant difference in survival was observed when different FHIT staining intensities (weak versus strong) were considered (median survival of 208 +/- 17 versus 234 +/- 34 days, P=0.665). Multivariate analysis using Cox regression including 11 variables confirmed the prognostic significance of FHIT expression next to performance status, tumor stage, and lactate dehydrogenase.

CONCLUSION

The presence of FHIT was correlated with a better prognosis for patients with SCLC.

Minimal influence of metallothionein over-expression on nickel carcinogenesis in mice

Metallothionein (MT) is a metal-binding protein associated with tolerance to metals and oxidative stress. Nickel is a metal carcinogen potentially acting through oxidative attack on critical biomolecules. We investigated the role of MT in nickel carcinogenesis using MT-transgenic mice that constitutively over-express MT-I in all tissues tested. Groups of 25 male MT-transgenic and wild type (C57BL/6; WT) mice received intramuscular injections of nickel subsulfide (Ni3S2) in both thighs at doses of 0 (control), 0.5, or 1.0 mg/site at 12 weeks of age and were observed for 104 weeks. Injection site tumors (ISTs; primarily fibrosarcomas) started occurring 45 weeks after nickel injection and IST incidence was similar in the WT (control - 0%, 0.5 mg/site - 20%, 1.0 mg/site - 40%) and MT-transgenic mice (control - 0%, 0.5mg/site - 28%, 1.0mg/site - 29%.). At the 0.5 mg/site dose the average time to IST in MT-transgenic mice was approximately 13 weeks shorter than in WT mice. Spontaneous lung tumors developed in 25% of control WT mice but none developed in control MT-transgenic mice. A nickel dose-related trend for increased lung tumors occurred in MT-transgenic mice but not in WT mice. Thus, the over-expression of MT did not significantly mitigate the carcinogenic response to nickel.

[Relationship between the reduction of FHIT expression and the development of cervical carcinoma]

OBJECTIVE

To explore the relationship between reduction of FHIT expression of fragile histidine triad (FHIT) and the development of cervical carcinoma.

METHODS

Expression of the FHIT product was detected by immunohistochemistry in 22 normal cervices and 35 cervical intra-epithelial neoplasias (CINs) as well as 60 primary invasive cervical carcinomas.

RESULTS

The rates for loss or reduction of expression of FHIT protein in the squamous epithelium of normal cervices, CIN I-II, CIN III and noninvasive carcinoma and invasive cervical carcinoma were 0% (0/22), 20% (4/20), 53.3% (8/15), 81.7% (49/60) respectively (P<0.05). Among the well differentiated, intermediately differentiated and poorly differentiated invasive cervical carcinoma, the rates for loss or reduction of expression of FHIT protein were 60.0% (6/10), 70.0% (14/20), and 96.7% (29/30) respectively (P<0.05). The rate of the impaired FHIT protein expression in the invasive cervical carcinoma with lymph node metastasis (90.9%) was higher than that without lymph node metastasis (79.6%).

CONCLUSION

The impaired FHIT protein expression might be a useful indicator in identifying the possibility of the progression of advanced CINs into invasive cervical carcinoma. FHIT protein expression might indicate the clinical characteristic of cervical carcinoma cells and the prognosis of cervical carcinoma.

Synergistic tumor suppression by coexpression of FHIT and p53 coincides with FHIT-mediated MDM2 inactivation and p53 stabilization in human non-small cell lung cancer cells

Aberrations of the tumor suppressor genes FHIT and p53 are frequently associated with a wide range of human cancers, including lung cancer. We studied the combined effects of FHIT and p53 proteins on tumor cell proliferation and apoptosis in human non-small cell lung carcinoma (NSCLC) cells in vitro and on tumor growth in animal models by adenoviral vector-mediated cotransfer of wild-type FHIT and p53 genes. We found that the coexpression of FHIT and p53 synergistically inhibited tumor cell proliferation in NSCLC cells in vitro and suppressed the growth of human tumor xenografts in nude mice. Furthermore, we found that this synergistic inhibition of tumor cell growth corresponded with the FHIT-mediated inactivation of MDM2, which thereby blocked the association of MDM2 with p53, thus stabilizing the p53 protein. Our results therefore reveal a novel molecular mechanism consisting of FHIT-mediated tumor suppression and the interaction of FHIT with other cellular components in the pathways regulating p53 activity. These findings show that combination treatment with synergistic tumor-suppressing gene therapy such as Ad-FHIT and Ad-p53 may be an effective therapeutic strategy for NSCLC and other cancers.

Reduced Fhit protein expression in nickel-transformed mouse cells and in nickel-induced murine sarcomas

Nickel compounds are carcinogenic and induce malignant transformation of cultured cells. Since nickel has low mutagenic potential, it may act predominantly through epigenetic mechanisms, including down-regulation of tumor suppressor genes. FHIT is a tumor suppressor gene whose expression is frequently reduced or lost in tumors and pre-malignant lesions. Previously, we have shown that the phosphohydrolase activity of Fhit protein, associated with its tumor suppressor action, is inhibited by nickel. In cells, such effect would assist in carcinogenesis. The latter could be further enhanced if nickel also lowered cellular levels of Fhit protein itself, e.g. by down-regulation of FHIT gene. To test this possibility, we determined Fhit protein and Fhit-mRNA levels in a nickel-transformed mouse cell line and in nickel-induced murine sarcomas. In B200 cells, derived by nickel treatment of BALB/c-3T3 cells and exhibiting a malignant phenotype, Fhit protein levels were 50% of those in the parental cells, while Fhit-mRNA expression remained unchanged. A decrease of up to > 90% in Fhit protein levels was also observed in 22 local sarcomas (mostly fibrosarcomas) induced by i.m. injection of nickel subsulfide in C57BL/6 and MT+ (C57BL/6 overexpressing metallothionein) mice, as compared with normal muscles. Moreover, Fhit was absent in 3 out of 10 sarcomas from MT+ mice and in 1 of 12 sarcomas from C57BL/6 mice. The lack of Fhit protein coincided with the absence of the Fhit-mRNA transcript in these tumors. However, in the other tumors, the decreased Fhit levels were not always accompanied by reduced expression of Fhit-mRNA. Thus, the observed lowering of Fhit protein levels is mostly associated with changes in mRNA expression and protein translation or turnover rates, and rarely with a full silencing of the gene itself. Overall, the decline of Fhit in cells or tissues malignantly transformed by nickel may indicate possible involvement of this effect in the mechanisms of nickel carcinogenesis.

[Allelic loss and down-regulation of FHIT gene expression in esophageal squamous cell carcinoma]

BACKGROUND & OBJECTIVE

Deletions and translocations involving the short arm of chromosome 3 (3p14) have been observed frequently in esophageal cancer. Fragile histidine triad (FHIT) gene is located in 3p14.2, and its deletion or abnormal expression was found in many kinds of cancers. The study was to investigate the alterations of FHIT gene, and its significance in esophageal squamous cell carcinoma (ESCC).

METHODS

The deletion of FHIT gene in 80 cases of ESCC was evaluated by microsatellite analysis, and the mRNA expression of FHIT gene in 20 cases of ESCC was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

Intragenic markers of FHIT gene, D3S3356, D3S3378, and D3S3361, showed homozygous in all samples. D3S1234 and D3S1540, located near FHIT, presented high heterozygosity. In the tested informative cases, loss of heterozygosity (LOH) of D3S1234 was detected in 30 out of 52 tumors (57.69%), and that of D3S1540 was observed in 38 out of 56 carcinomas (67.86%). Reduced expression of FHIT mRNA occurred in 15 of 20 (75.00%) cases, and was often accompanied with LOH. However, the FHIT down-regulation was not always coincident with LOH.

CONCLUSIONS

The abnormal expression of FHIT gene occurred frequently in ESCC. LOH was the main factor leading to down-regulation of FHIT expression. Epigenetic mechanism might be associated with reduced expression of FHIT in a part of ESCC cases.

5'-CpG island methylation of the FHIT gene is associated with reduced protein expression and higher clinical stage in cervical carcinomas

Aberrant transcription of the FHIT gene has been observed in many solid tumors, suggesting that 5'-CpG island methylation of the FHIT gene is involved in tumor development. The authors investigated the status of the 5'-CpG island methylation of the FHIT gene and protein expression in a series of 40 cervical carcinomas and 10 normal cervical epithelial samples, and correlated the data with clinicopathological findings. Methylation-specific PCR was applied to detect the incidence of the 5'-CpG island methylation, and immunohistochemistry was used for FHIT protein staining. 5'-CpG island methylation of the FHIT gene was detected in 40% (16/40) of the cervical cancer samples and in none of normal cervical epithelial specimens. Furthermore, the 5'-CpG island methylation was positively associated with clinical stage (p=.002). All the normal cervical epithelial samples (10/10) and 90% (36/40) of the cervical carcinomas were positive when the unmethylated primer pair was applied. Of the 16 cervical carcinomas with 5'-CpG island methylation of the FHIT gene by PCR, 15 showed reduced FHIT protein expression. This study suggests that 5'-CpG island methylation plays an important role in inactivation of the FHIT gene in cervical cancer.

Acylphosphatase overexpression triggers SH-SY5Y differentiation towards neuronal phenotype

An acylphosphatase (AcPase) overexpression study was carried out on SH-SY5Y neuroblastoma cells, using a green fluorescent fusion protein (AcP-GFP), with GFP acting as a reporter protein. The cellular proliferation rate was significantly reduced by overexpression of AcPase by a factor of ten. In contrast, clones transfected with two inactive AcPase mutants showed a growth rate comparable to control cells. This suggests that AcPase catalyzes the proliferative down-regulation. AcPase-overexpressing clones showed a physiological mortality rate as assessed by an MTT reduction test and by evaluation of necrotic markers. DNA fragmentation analysis and assays of caspase-3 and poly (ADP-ribose) polymerase (PARP)-active fragments showed no evidence of any apoptotic pattern. AcPase overexpression led to a marked increase in PARP activity as well as Bcl-2 content; these are commonly up-regulated during differentiative processes in neuronal cells. In fact, the typical differentiation marker, growth-associated-protein 43, was significantly up-regulated. Microscopic observations also showed a clear increase in the differentiative phenotype in AcPase-overexpressing cells. Our results clearly show that AcPase plays a primary causative role in neuronal differentiation.

Prognostic significance of p53 and FHIT in advanced oropharyngeal carcinoma

OBJECTIVE

To determine the prognostic significance of p53 and fragile histidine triad (FHIT) expression in advanced oropharyngeal squamous cell carcinoma.

STUDY DESIGN

A retrospective collection of clinical data was correlated with the protein expression.

METHOD

The expression of p53 and FHIT in specimens from patients with previously untreated advanced squamous cell carcinoma of the oropharynx was determined by immunohistochemistry. The expression of p53 and FHIT was statistically correlated with survival outcome. The primary endpoints were overall survival and disease-free survival.

RESULTS

Thirty-four patients were analyzed in this study. Overexpression of p53 was observed in 41.2% (14/34) of tumors and was associated with a trend toward an improved overall survival using univariate (P =.1088, risk ratio [RR] = 0.503) and multivariate (P =.1533, RR = 0.470) analyses. Marked reduction or complete absence of FHIT expression was observed in 57.6% (19/33) of tumors. Patients with tumors showing no reduction in FHIT expression had a lower overall survival using univariate (P =.04, RR = 2.27) and multivariate (P =.013, RR = 4.41) analyses.

CONCLUSION

Overexpression of p53 predicted a trend toward an improved prognosis, whereas no reduction in FHIT expression predicted a significantly poorer outcome in patients with advanced oropharyngeal cancer.

FHIT mRNA and protein expression in hepatocellular carcinoma

Loss of fragile histidine triad (FHIT) gene expression is seen in approximately 50% of hepatocellular carcinomas in China. However, little information is available on FHIT expression in hepatocellular carcinoma in the United States, where carcinogen exposure is generally lower. Investigations of FHIT mRNA in hepatocellular neoplasms and paired non-neoplastic tissues demonstrated normal-sized FHIT transcripts in all non-neoplastic tissues and in all neoplasms including 11 hepatocellular carcinomas, two fibrolamellar carcinomas, and four benign proliferative lesions. In addition, all but one malignant and all benign neoplasms showed aberrant smaller transcripts. The smaller aberrant transcripts were overexpressed in 6/11 hepatocellular carcinomas and 1/2 fibrolamellar carcinomas. An additional 79 hepatocellular carcinomas, 12 fibrolamellar carcinomas and 15 hepatic adenomas were examined for FHIT expression by immunohistochemistry. No loss of immunostaining was seen in 67/79 (85%) of hepatocellular carcinomas, while a moderate or marked decrease was seen in 12/79 (15%). Fibrolamellar carcinomas and hepatic adenomas showed no loss of FHIT expression. In conclusion, hepatocellular carcinomas retained expression of normal FHIT mRNA transcripts, but also showed universal expression of smaller sized aberrant transcripts and commonly overexpressed these aberrant transcripts. Loss of FHIT protein expression is relatively uncommon in this cohort from the United States, where exposure to hepatic carcinogens is generally low.

[Fragile histidine triad expression in rhabdomyosarcoma]

OBJECTIVE

To study the expression of fragile histidine triad (FHIT) protein in rhabdomyosarcoma(RMS) and the possible mechanisms of its effect on tumor.

METHODS

Immunohistochemical technique(SP) was used to detect the expression of FHIT in 44 cases of RMS and 20 cases of normal skeletal muscles.

RESULTS

Reduced expression of FHIT was 68.2% (30/44) in the cases of RMS, and was 35% (7/20) in the cases of normal skeletal muscles; a significant difference was seen between the two groups(P < 0.05). There was no significant relationship of the expression of FHIT with the sex of the patient and the histological type and grade of the tumor(P > 0.05). However, a significant relationship was observed between the expression of FHIT and the prognosis of the tumor in respect to relapse and metastasis of tumor(P < 0.05).

CONCLUSION

The reduced expression of FHIT may play an important role in the development and progression of rhabdomyosarcoma, and thus may become a new prognostic marker in RMS.

Altered p16INK4a and Fhit expression in carcinogenesis and progression of human oral cancer

To further characterize the biological and clinical role of molecular alterations involved in oral squamous carcinogenesis, the immunohistochemical expression level of two tumor suppressor genes, fragile histidine triad and p16INK4a, in non-carcinomatous squamous epithelia and head and neck squamous cell carcinoma was determined. In addition, human papillomavirus infection determined by PCR assay and the use of alcohol and cigarettes were evaluated. In this study 28 non-carcinomatous squamous epithelia and 57 head and neck squamous cell carcinoma were considered. The expression levels of fragile histidine triad were lower in head and neck squamous cell carcinoma than in non-carcinomatous squamous epithelia. In contrast, p16INK4a is expressed in malignant lesions (51% of the cases analyzed), but not in non-carcinomatous squamous epithelia. No correlation between gene expression alterations of the two tumor suppressors was observed. PCR analysis showed that HPV DNA was present in 5 of the 57 malignant lesions analyzed (8.8%). None of the factors described above, despite changes in gene expression and HPV infection, appears to be associated with alcohol use and/or tobacco smoking and clinical outcome. Our data showed that fragile histidine triad and p16INK4a expression are altered in malignant lesions. Most likely, the decreasing levels of fragile histidine triad is directly involved in cancer development, while the accumulation of p16INK4a in head and neck squamous cell carcinoma may be the consequence of loss of functional tumor suppressor retinoblastoma pathway.

Clinical significance of Fhit expression in development of colorectal carcinoma of various macroscopic types

It is unclear how expression of the FHIT (fragile histidine triad) gene by the colorectal neoplasm correlates with histogenesis and progression of the disease. We studied the association between expression of Fhit protein and development of colorectal carcinoma (CRC). We also examined relations between Fhit protein expression, macroscopic type, Ki-67 labeling index (LI), and p53 overexpression in carcinoma in situ. We examined 27 colorectal adenomas, 82 carcinomas in situ and 21 invasive CRCs resected endoscopically or surgically. The carcinomas in situ comprised three macroscopic types: polypoid (n=27), superficial (flat elevated, n=27; depressed, n=10) and granulonodular laterally spreading tumor (G-LST, n=23). Fhit, Ki-67, and p53 overexpression were examined immunohistochemically. Levels of Fhit protein were lower in invasive CRC than in adenoma and carcinoma in situ (p<0.01). In carcinoma in situ, reduced Fhit expression was observed in 7 of 22 (31.8%) polypoid types, 13 of 27 (48.1%) superficial flat elevated types, 8 of 10 (80%) superficial depressed types and 7 of 23 (30.4%) G-LST. Frequencies of reduced Fhit expression were significantly higher in the polypoid type and G-LST lesions than in the depressed type (p<0.05). Reduced expression of Fhit protein was related significantly to Ki-67 LI and p53 overexpression in carcinoma in situ (p<0.01). The present findings suggest that reduced expression of Fhit protein is related to development of colorectal neoplasm. Polypoid CRC and G-LST appear to differ from superficial depressed CRC in terms of Fhit expression.

Differential expression of the invasion-associated locus B (ialB) gene of Bartonella bacilliformis in response to environmental cues

Bartonella bacilliformis is the causative agent of the biphasic human disease, Oroya fever. During the primary disease phase, up to 100% of the circulating erythrocytes can be parasitized and 80% lysed. During the secondary phase of this disease, bacterial invasion shifts to endothelial cells lining the vasculature. B. bacilliformis is transferred between human hosts by the sandfly, Lutzomyia verrucarum. To investigate the regulation of ialB by environmental cues signaling vector-to-host transmission; nuclease protection assays were performed to compare the amount of ialB mRNA in bacteria subjected to temperature shift, pH change, oxidative stress, or hemin limitation. The amount of ialB mRNA increased by 223-310% in acid-treated samples and decreased by 28-39% in base-treated samples as compared to bacteria kept at pH 7.2. B. bacilliformis samples showed a 56-63% and 74-80% decrease in ialB mRNA when shifted to 37 degrees C from growth temperatures of 20 and 30 degrees C, respectively. Oxidative stress (1 mM H(2)O(2)) and hemin limitation had no significant effect on mRNA levels. Determination of IalB protein amounts using SDS-PAGE and immunoblotting showed the greatest amounts of IalB under acidic conditions or at 20 degrees C. The least amount of IalB was synthesized under basic conditions or at 37 degrees C. The viability of wild-type B. bacilliformis under the various experimental culture conditions was determined and found not to affect ialB mRNA amounts in these experiments. Finally, we compared the survival of wild-type and ialB mutant B. bacilliformis and found no difference in the viability of these two strains, demonstrating that IalB does not aid bacterial survival under these conditions.