Proteomic profiles in hyperandrogenic syndromes

BACKGROUND

Polycystic ovary syndrome (PCOS) and congenital adrenal hyperplasia (CAH) represent the most common causes of hyperandrogenism. Although the etiopathogeneses of these syndromes are different, they share many clinical and biochemical signs, such as hirsutism, acne, and chronic anovulation. Experimental data have shown that peripheral T-lymphocytes function as molecular sensors, being able to record molecular signals either at staminal and mature cell levels, or hormones at systemic levels.

METHODS

Twenty PCOS women and 10 CAH with 21-hydroxylase deficiency, aged between 18-35 yr, were studied. T-cells purified from all patients and 20 healthy donors have been analyzed by 2-dimensional gel electrophoresis. Silver-stained proteomic map of each patient was compared with a control map obtained by pooling protein samples of the 20 healthy subjects.

RESULTS

Spots of interest were identified by peptide mass fingerprint. Computer analysis evidenced several peptidic spots significantly modulated in all patients examined. Some proteins were modulated in both syndromes, others only in PCOS or in CAH. These proteins are involved in many physiological processes as the functional state of immune system, the regulation of the cytoskeleton structure, the oxidative stress, the coagulation process, and the insulin resistance.

CONCLUSION

Identification of the physiological function of these proteins could help to understand ethiopathogenetic mechanisms of hyperandrogenic syndromes and its complications.

Myc down-regulation affects cyclin D1/cdk4 activity and induces apoptosis via Smac/Diablo pathway in an astrocytoma cell line

OBJECTIVES

We investigated the antiproliferative effect of Myc down-regulation via cell proliferation inhibition, cell cycle perturbation and apoptosis in two human astrocytoma models (T98G and ADF) steadily expressing an inducible c-myc Anti-sense RNA.

MATERIALS AND METHODS

Cell growth experiments were performed using the trypan blue dye exclusion test and cell cycle analysis was evaluated by flow cytometry. Cell cycle molecules were detected by Western blot analysis, co-immunoprecipitation and reverse transcription-polymerase chain reaction assays.

RESULTS

We showed that Myc down-regulation in astrocytoma cells led to G1 accumulation and an inhibition of cell proliferation characterized by S phase delay. Co-immunoprecipitation experiments detected formation of inactive cyclin D1/cdk4 complexes as evaluated by presence of an active unphosphorylated form of retinoblastoma protein, the best characterized target substrate for cyclin D1/cdk4 complex, in ADF pINDc-myc anti-sense 7 cells. We also found that either p57Kip2 "apice" or p27Kip1 "apice" inhibitors bound to cyclin D1/cdk4 complex, thus, suggesting that they cooperated to inhibit the activity of cyclin D1/cdk4. Moreover, c-Myc down-regulation led to activation of the apoptotic mitochondrial pathway, characterized by release of cytochrome c and Smac/Diablo proteins and by reduction of c-IAP levels through activation of proteasome-mediated protein degradation system.

CONCLUSIONS

Our results suggest that c-Myc could be considered as a good target for the study of new approaches in anticancer astrocytoma treatment.

Mitotane increases the radiotherapy inhibitory effect and induces G2-arrest in combined treatment on both H295R and SW13 adrenocortical cell lines

Mitotane, 1,1-dichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane (o,p'-DDD) is an agent with adrenotoxic effect, which is able to block cortisol synthesis. This drug and radiotherapy are used also in adrenal cancer treatment even if their biological action in this neoplasia remains unknown. We investigated the effects of o,p'-DDD and ionizing radiations (IR) on cell growth inhibition and cell cycle perturbation in H295R and SW13 adrenocortical cancer cells. Both cell lines were irradiated at a 6 Gy dose and were treated with o,p'-DDD 10(-5) M separately and with IR/o,p'-DDD in combination. This combination treatment induced an irreversible inhibition of cell growth in both adrenocortical cancer cells. Cell cycle analysis showed that IR alone and IR/o,p'-DDD in combination induced the cell accumulation in the G2 phase. At 120 h after IR, the cells were able to recover the IR-induced G2 block while cells treated with IR/o,p'-DDD were still arrested in G2 phase. In order to study the molecular mechanism involved in the G2 irreversible arrest, we have considered the H295R cell line showing the highest inhibition of cell proliferation associated with a noteworthy G2 arrest. In these cells, cyclin B1 and Cdk2 proteins were examined by western blot and Cdk2 kinase activity measured by assay kit. The H295R cells treated with IR/o,p'-DDD shared an increase in cyclin B1 amount as the coimmunoprecipitation of Cdc2-cyclin B1 complex. The kinase activity also shows an increase in the treated cells with combination therapy. Moreover, in these cells, sequence analysis of p53 revealed a large deletion of exons 8 and 9. The same irreversible block on G2 phase, induced by IR/o,p'-DDD treatment, happened in H295R cells with restored wild-type p53 suggesting that this mechanism is not mediated by p53 pathway.

Modulation of proteomic profile in H295R adrenocortical cell line induced by mitotane

Mitotane, 1,1-dichloro-2-(o-chlorophenyl)-2-(p-chloro-phenyl) ethane (o,p'-DDD), is a compound that represents the effective agent in the treatment of the adrenocortical carcinoma (ACC), able to block cortisol synthesis. In this type of cancer, the biological mechanism induced by this treatment remains still unknown. In this study, we have already shown a greater impairment in the first steps of the steroidogenesis and recognized a little effect on cell cycle. We also evaluated the variation of proteomic profile of the H295R ACC cell line, either in total cell extract or in mitochondria-enriched fraction after treatment with mitotane. In total cell extracts, triose phosphate isomerase, alpha-enolase, D-3-phosphoglycerate dehydrogenase, peroxiredoxin II and VI, heat shock protein 27, prohibitin, histidine triad nucleotide-binding protein, and profilin-1 showed a different expression. In the mitochondrial fraction, the following proteins appeared to be down regulated: aldolase A, peroxiredoxin I, heterogenous nuclear ribonucleoprotein A2/B1, tubulin-beta isoform II, heat shock cognate 71 kDa protein, and nucleotide diphosphate kinase, whereas adrenodoxin reductase, cathepsin D, and heat shock 70 kDa protein 1A were positively up-regulated. This study represents the first proteomic study on the mitotane effects on ACC. It permits to identify some protein classes affected by the drug involved in energetic metabolism, stress response, cytoskeleton structure, and tumorigenesis.

O2/3 exposure inhibits cell progression affecting cyclin B1/cdk1 activity in SK-N-SH while induces apoptosis in SK-N-DZ neuroblastoma cells

In search for innovative therapeutic agents for children neuroblastoma, the oxygen therapy could be considered an alternative anti-tumoral treatment. Given the physiochemical properties of O(2/3) gas mixture including fairly low aqueous solubility and spreading, and the interesting perspective of hyperoxia, we analyzed the inhibitory effect of O(2/3) treatment on two human neuroblastoma cell lines (SK-N-SH and SK-N-DZ). In this study, we demonstrated that O(2/3) treatment was able to induce cell growth inhibition and cell cycle perturbation in both cell lines. We observed an arrest at G(2) phase, accompanied by an alteration in the expression and localization of cyclin B1/cdk1 complex and a reduction in its activity in SK-N-SH cells. This reduction was consistent with the increase in both Wee1 and chk1 protein levels. On the contrary, O(2/3) induced apoptosis in SK-N-DZ cells via caspase 3 activation and Poly ADP-ribose polymerase-1 (PARP) cleavage, associated with an increase in the pro-apoptotic Bax protein. Consequently, we considered the possibility of improving the responsiveness to chemotherapeutic agents such as Cisplatin, Etoposide, and Gemcitabine in combination with O(2/3) treatment. The combined treatments produced a stronger cell inhibitory effect than Cisplatin and Etoposide used alone in SK-N-SH cells. On the contrary, the combination data were not significantly different from O(2/3) treatment alone in SK-N-DZ cells, thus suggesting that the obtained changes in cell growth inhibition were due to the effect of O(2/3) alone.

Antifungal prophylaxis with azole derivatives

In recent years, several reports have underlined the increasing role of fungal infections as a cause of morbidity and mortality in hospitalised patients. For this reason, and also in light of the high mortality rate associated with these infections, chemoprophylaxis has been advocated by several authors. The available evidence suggests that both fluconazole and itraconazole are able to decrease candida colonisation and infection, when compared with placebo or with nonabsorbable antifungals. Data seem also to suggest that a decrease in fungus-related mortality can be achieved with prophylaxis, although with little effect on overall mortality, probably because of the importance of severe underlying diseases. Itraconazole proved to be effective in the prevention of fungal infections, including invasive aspergillosis, although with increased incidence of side-effects, often leading to treatment discontinuation. The other side of the coin is that antifungal prophylaxis might have untoward effects, such as the selection of triazole-resistant Candida strains or the induction of resistance. In addition, some authors have suggested that the use of triazoles might modulate the pattern of infecting organisms in cancer patients, increasing the risk of both aspergillosis and bacteremia. In conclusion, antifungal prophylaxis with triazole antifungals should be used with caution, only in patients at high risk for invasive fungal infections. These include allogeneic bone marrow transplant patients (especially those with mismatched or unrelated donors), acute myeloid leukaemia patients treated with high-dose cytarabine (C-ara), very-low-birth-weight infants, patients with chronic granulomatous disease, and high-risk surgical and intensive-care unit patients.

Biological indicators of aggressiveness in T1 ductal invasive breast cancer

BACKGROUND

Apoptosis plays an important role in the maintenance of tissue homeostasis. When defective, this process could contribute to the pathogenesis and the progression of tumors. On this basis, we investigated the combined effect of Bcl-2 and Bax expression, known regulators of apoptotic processes, in the activation of apoptosis in breast cancer. Their relationship with DNA content and proliferative activity was also studied in order to more accurately define breast cancer patients' prognosis and treatment.

MATERIALS AND METHODS

In this study we investigated 76 T1 ductal invasive breast cancers and 76 normal epithelium samples for Bcl-2 and Bax expression by immunohistochemistry, for apoptosis by tunel assay and for DNA content and proliferative activity by flow cytometry.

RESULTS

High levels of Bcl-2 were associated with prevention of apoptosis. Conversely high Bax expression was found to be related to apoptosis. DNA ploidy was strictly related to the proliferative activity. In addition most of the tumors showing high Bcl-2 expression were aneuploid.

CONCLUSION

This report suggests that Bax over-expression could accelerate apoptotic cell death by counteracting the ability of Bcl-2 to inhibit apoptosis. These data also suggest that the ratio Bcl-2/Bax and their relationship with the activation of apoptosis could be used as predictive indicators of breast cancer patients' prognosis and response to conventional therapy.

Myc down-regulation induces apoptosis in M14 melanoma cells by increasing p27(kip1) levels

In recent years, increasing evidence indicated the importance of a deregulated c-myc gene in the melanoma pathogenesis. We have previously demonstrated that treatment of melanoma cells with c-myc antisense oligodeoxynucleotides can inhibit cell proliferation and activate apoptosis. To gain insight into the mechanisms activated by Myc down-regulation, we have now developed an experimental model that allows modulating Myc protein expression in melanoma cells. This was achieved by originating stable melanoma cell clones expressing ecdysone-inducible c-myc antisense RNA. We show that the induction of c-myc antisense RNA in M14 melanoma cells leads to an inhibition of cell proliferation characterized by accumulation of cells in the G(1) phase of the cell cycle (up to 80%) and activation of apoptosis (50%). These data are associated with an increase of p27(kip1) levels and a significant reduction of the cdk2-associated kinase activity. In addition, we show that an ectopic overexpression of p27(kip1) in this experimental model can enhance the apoptotic rate. Our results indicate that down-regulation of Myc protein induces a G(1) arrest and activates apoptosis by increasing p27(kip1) content in melanoma cells, that are known to be defective for the p16-cyclinD/cdk4-pRb G(1) checkpoint. This is particularly relevant for identifying new therapeutic strategies based on the re-establishment of the apoptotic pathways in cancer cells.

E-cadherin and alpha-catenin expression during tumor progression of cervical carcinoma

OBJECTIVE

The objective of this study was to determine whether a relationship between the E-caherin molecule and the E-cadherin-associated cytoplasmic molecule, alpha-catenin, could provide additional information in the neoplastic progression of cervical cancer.

METHODS

In this study we investigated by immunohistochemistry E-cadherin (E-cad) and alpha-catenin (alpha-cat) expression in 57 cervical biopsy samples representative of normal exocervical epithelium, viral (human papillomavirus (HPV) infection) and dysplastic lesions (low- and high-grade lesions), and invasive squamous cell carcinoma. The presence of immunostaining and the pattern of distribution of these molecules were correlated with the histological diagnosis (normal cervical epithelium vs HPV, cervical intraepithelial neoplasia (CIN), and invasive carcinoma).

RESULTS

The correlation between alpha-cat expression and the histological diagnosis was statistically significant (chi2 test, P < 0.0077); moreover, E-cad and alpha-cat distributions were significantly correlated with the histological classification (P < 0.0001 and P < 0.0043, respectively).

CONCLUSION

These results suggest that not only E-cad but also alpha-cat are associated with the loss of differentiation in CIN and squamous cell carcinomas; thus the coexpression of E-cad and alpha-cat may represent a discriminant of malignant potential and could provide an additional criterion to define high-grade CIN.

c-myc antisense oligodeoxynucleotides enhance the efficacy of cisplatin in melanoma chemotherapy in vitro and in nude mice

This study was designed to assess the efficacy of a new antimelanoma therapeutic strategy that relies on the use of a c-myc antisense 15-mer phosphorothioate oligodeoxynucleotide ([S]ODN), in combination with cisplatin (cis-diamminedichloroplatinum; DDP), which is currently used in the clinical management of melanoma patients. Proliferation and colony formation of melanoma cells were both inhibited by the DDP/c-myc antisense [S]ODN combination to a greater extent than that observed with either agent alone. Inhibition was most effective when DDP was followed by c-myc antisense [S]ODNs. Cell cycle flow cytometric analysis of cells exposed to the two agents either alone or in combination demonstrated that (a) c-myc antisense [S]ODNs induced an accumulation of cells in S phase and apoptosis in a fraction of the cells, detectable at day 5 after the beginning of treatment; (b) DDP induced a block in G2-M phase detectable at day 1, which was partially recovered, and apoptosis similar in extent to that induced by c-myc antisense [S]ODNs; and (c) DDP and c-myc antisense [S]ODNs together induced arrest in G2-M phase, which was maximum at day 3, i.e., delayed as compared to the block induced by DDP. The combination induced a higher percentage of apoptosis, evident at day 3 from the start of treatment, that correlated with a marked reduction in Bcl-2 expression. Mice bearing human melanoma xenografts and treated sequentially with DDP and c-myc antisense [S]ODNs showed a higher inhibition of tumor growth, reduction in the number of lung metastases, and increase in life span compared with those treated with either agent alone. Together, these data lend support to the development of anticancer therapies involving oncogene-targeted antisense ODNs and conventional antineoplastic drugs.

Effects of poly(ADP-ribose) polymerase inhibition on cell death and chromosome damage induced by VP16 and bleomycin

Poly(ADP-ribose) polymerase (PARP) is a DNA-binding protein involved in cellular response to various genotoxic agents. To understand the role of PARP in the mechanisms which lead from specific DNA damage to cell death, we studied the effects of PARP inhibition in human lymphoblasts damaged with bleomycin (BLM) and VP16. These agents can induce DNA breakage but through different mechanisms, enabling the study of the different effects of PARP in inducing apoptosis in damaged cells. We demonstrate that in lymphoblasts VP16 treatment induces apoptosis to a greater extent than BLM treatment, and that PARP inhibition reduces VP16-induced apoptosis whereas it has no effect on BLM-induced apoptosis. After VP16 treatment with PARP inhibition, a reduction in the depletion of the proliferative compartment and a G2/M phase arrest are observed. Therefore, the increase in cell viability and the reduction in chromosome damage may both be the result of a prolonged DNA repair time. Hence, PARP appears to play a significant role in VP16-induced apoptosis and not in BLM-induced apoptosis. Since apoptosis is important in tumor treatment these findings might be useful when considering the combined employment of PARP inhibition with antineoplastic drugs.

N-methylformamide induces changes on adhesive properties and lung-colonizing potential of M14 melanoma cells

We have studied whether N-methylformamide can affect the expression pattern of adhesion molecules and the attachment behaviour of M14 human melanoma cells. The role of N-methylformamide on experimental and spontaneous pulmonary metastases from M14 cells in nude mice was also investigated. We demonstrate that N-methylformamide in vitro pretreatment of M14 cells, although inducing a significant increase in the expression of alpha2beta1, alpha6beta1 and alpha(v)beta3 integrin receptors, slightly modifies alpha5beta1 heterodimer and beta1 subunit expression. After this modulation, enhancement of cell adhesion to laminin, collagen I, vitronectin and fibrinogen, which is blocked by specific anti-integrin antibodies, also occurs. No changes in binding to fibronectin are observed. In vitro N-methylformamide pretreatment also results in an increased number of experimental nodules and in a decrease in spontaneous metastases. Moreover, in vivo treatment with N-methylformamide significantly reduces the number of spontaneous metastases. Collectively, these data show that N-methylformamide modulates the expression of some adhesion receptors, cell adhesion to laminin, collagen I, vitronectin and fibrinogen as well as the metastatic behaviour of M14 cells. Our data also suggest that the effect of N-methylformamide might be evaluated in combination with antineoplastic agents for the treatment of human melanoma.

Induction of apoptosis in HT-29 cells infected with SA-11 rotavirus

Rotavirus infection is associated both in vivo and in vitro with a series of subcellular pathological alterations leading to cell lysis. It has been suggested that these modifications can play a key role in the pathogenesis of rotavirus-associated diarrheal disease. We describe the effects of SA-11 rotavirus infection in HT-29 cells, a human enterocyte-like cell line. Cytological analyses suggested that the viral-induced cytopathic process, including chromatin clumping, can be referred to as apoptosis, the cell death pathway alternative to necrosis. A time course of the process was performed to investigate whether rotavirus-associated cell death showed specific injury signs. HT-29-infected cells were analyzed by scanning and transmission electron microscopy and features of apoptosis such as blebbing of the plasma membrane, peripheral condensation of chromatin, and fragmentation of the nucleus were observed. Specific changes occurring in cell-substrate adhesion and in some organelles relevant for viral maturation, i.e., rough endoplasmic reticulum, were detected. These findings indicate a role for apoptosis in the rotavirus infection process and its related cytopathology, and also suggested that specific histological alterations such as derangement of enterocytes are associated with the pathogenesis of rotavirus-induced diarrheal disease and could be a direct consequence of viral-triggered apoptosis.

EGF-R expression in ductal breast cancer: proliferation and prognostic implications

We studied epidermal growth factor receptor (EGF-R) expression in relation to steroid receptor status, flow cytometric DNA content and S-phase fraction (%S) in a selected case series of 129 ductal primary operable breast cancer to determine the possible role of EGF-R in prognosis assessment. EGF-R expression was positively related with proliferation activity, suggesting that EGF-R could be involved in the regulation of breast cancer cell growth. We found about 80% of highly proliferating DNA aneuploid tumors in the EGF-R positive category, while the EGF-R negative tumors showed a lower frequency of highly proliferating DNA aneuploid tumors (57%), confirming the important role of EGF-R in breast cancer aggressiveness and progression. No relationship between EGF-R expression and steroid receptor status was observed. To better understand how EGF-R and estrogen receptor (ER) operate together to stimulate breast cancer cell growth, we analyzed the %S in the two groups of ER negative (ER-) and ER positive (ER+) tumors, stratifying the patients on the basis of EGF-R tumor positivity. Here breast tumor proliferation activity seems mainly to be induced by the stimulus of EGF-R, the %S values of the EGF-R negative tumors in the ER- and ER+ groups being 6.1 and 6.9%, respectively. Instead, the median %S of EGF-R positive tumors was 10% in the ER- class and 14% in the ER+ group. The analysis of the percentages of 5-year patient disease free survival were 84% for patients with EGF-R negative tumors and 61% for patients with EGF-R positive lesions, respectively. The data reported here further show the crucial role of EGF-R in breast cancer cell growth and that the EGF-R overexpression is indicative of a poor prognosis.

Induction of apoptosis in HT-29 cells infected with SA-11 rotavirus

Rotavirus infection is associated both in vivo and in vitro with a series of subcellular pathological alterations leading to cell lysis. It has been suggested that these modifications can play a key role in the pathogenesis of rotavirus-associated diarrheal disease. We describe the effects of SA-11 rotavirus infection in HT-29 cells, a human enterocyte-like cell line. Cytological analyses suggested that the viral-induced cytopathic process, including chromatin clumping, can be referred to as apoptosis, the cell death pathway alternative to necrosis. A time course of the process was performed to investigate whether rotavirus-associated cell death showed specific injury signs. HT-29-infected cells were analyzed by scanning and transmission electron microscopy and features of apoptosis such as blebbing of the plasma membrane, peripheral condensation of chromatin, and fragmentation of the nucleus were observed. Specific changes occurring in cell-substrate adhesion and in some organelles relevant for viral maturation, i.e., rough endoplasmic reticulum, were detected. These findings indicate a role for apoptosis in the rotavirus infection process and its related cytopathology, and also suggested that specific histological alterations such as derangement of enterocytes are associated with the pathogenesis of rotavirus-induced diarrheal disease and could be a direct consequence of viral-triggered apoptosis.

Fungal infections in patients undergoing bone marrow transplantation: an approach to a rational management protocol

Candida sp. and Aspergillus sp. are the most common fungal pathogens causing infection in bone marrow transplant recipients and represent an increasing cause of morbidity and mortality. At this time there is no generally accepted rule for the antifungal management of these complications. Antifungal drugs in immunocompromised patients are usually administered for prophylaxis, for therapy of specific infections or for empirical or preemptive therapy. The present article reports schedules of administrations and pediatric and adult dosages of the main antifungal drugs presently available, (fluconazole, itraconazole, amphotericin B deoxycholate, lipid formulations of amphotericin B and flucytosine), together with their spectrum of action and main toxicities. Thereafter, the available information about prevention and treatment of fungal infections in bone marrow transplant recipients is summarized. Briefly, fluconazole remains the drug of choice for prevention of Candida infections in bone marrow transplant recipients, while itraconazole has been seldomly used for this indication, due to erratic oral absorption. However, new itraconazole formulations are being studied, that might disclose new clinical perspectives, due to improved bioavailability. The duration of prophylaxis is still an open issue. Resistance to the new azoles may become a problem in the near future. For this reason, it is likely that the approach to the use of these new drugs should be similar to the one commonly used for antibacterial drugs, i.e. based on pathogen-related, drug-related and host-related factors. Mainly due to lack of diagnostic tools, very little studies have been performed for prevention of aspergillosis. Available data seem to show that there might be a role for low-dose intravenous amphotericin B, which has shown to be effective for secondary prophylaxis. Itraconazole and intranasal amphotericin B have been studied, as well. Although fluconazole and itraconazole (in the rare instances in which the oral route is reliable) can also have therapeutic indications, both for empirical and for specific therapy, amphotericin B (with or without flucytosine) remains the main therapeutic option. New antifungal drugs and new supportive strategies (i.e. role of hematopoietic growth factors) are in the research pipeline and will hopefully disclose new perspectives in the near future.

Biologic characteristics of T1 papillary bladder cancer. Flow cytometric study of paraffin-embedded material

DNA ploidy, proliferative activity (evaluated in terms of the proliferative index [PI]) and epidermal growth factor receptors (EGF-R) expression in primary bladder cancer in 52 patients were studied by means of flow cytometry and immunohistochemistry. Forty of the 52 tumors yielded evaluable DNA histograms: 22 were diploid (55%) and 18 aneuploid (45%) (median DNA index = 1.5). Ninety-five percent of the tumors were positive for EGF-R expression. The median PI value of the entire case series, estimated with a mathematical model, was 5.4%, or 6.7% in diploid tumors and 12.1% in aneuploid ones. EGF-R expression was higher in aneuploid than diploid tumors. Most of the well-differentiated tumors were diploid, while aneuploid populations and positivity for EGF-R expression were more frequent in poorly and moderately differentiated tumors. No differences in proliferative activity were observed in relation to grade. Overexpression of EGF-R in aneuploid tumors and a relationship between it, proliferative activity and grading were observed. The disease-free survival rates were 72% and 91% for patients with aneuploid and diploid tumors, respectively.

N-methylformamide as a potential therapeutic approach in colon cancer

PURPOSE

The effect of N-methylformamide, used in combination with the antineoplastic drugs adriamycin and cisplatin, on the cell survival of a colon carcinoma cell line (HT-29) was investigated. To better understand the mechanism involved in N-methylformamide-mediated chemosensitization, we evaluated the N-methylformamide effect on cell volume and surface expression of some integrins molecules (VLA2, VLA5, and VLA6) of the HT-29 cell line.

METHODS

The cell survival was evaluated by clonogenic assay; integrins surface expression was analyzed by means of flow cytometry; cell volumes were determined using a Coulter Channalyzer.

RESULTS

A Noncytotoxic dose of N-methylformamide (170 mM) sensitizes the HT-29 cell line to the lethal activity of both adriamycin and cisplatin. The analysis of cell volume showed that N-methylformamide exposure induces an increase in cell volume. Flow cytometric analysis of VLA2, VLA5, and VLA6 receptors showed that N-methylformamide increases the expression of the three integrins by 30 to 40 percent.

CONCLUSION

The plasma membrane could constitute one of the N-methylformamide targets and might be involved in the differentiation and chemosensitizing effects caused by this agent. Moreover, N-methylformamide could improve colon cancer treatment when used in combination with antineoplastic drugs.

Integrin beta 4 expression in the neoplastic progression of cervical epithelium

Integrin alpha 6 beta 4, a putative laminin receptor, is expressed in normal squamous epithelium and in squamous cell carcinomas. We evaluated by immunohistochemistry the topography of the beta 4 subunit in 35 biopsy samples representative of the sequence from normal exocervical epithelium to invasive squamous cell carcinoma. In normal and metaplastic squamous cervical epithelium, in condylomas, and in squamous epithelium with low-grade dysplasia (CIN 1), beta 4 was detected in basal and parabasal cells. In high-grade CIN (2-3) there was enhanced beta 4 expression and upward shift of beta 4 topography to the whole epithelial thickness. The beta 4 chain was diffusely expressed in most invasive squamous cell carcinomas. These observations suggest that profound alterations in the expression of the alpha 6 beta 4 adhesion glycoprotein occur in the intraepithelial phase of cervical carcinogenesis.