VISTA/CTLA4/PD1 coexpression on tumor cells confers a favorable immune microenvironment and better prognosis in high-grade serous ovarian carcinoma

Introduction

Immunotherapy by blocking immune checkpoints programmed death/ligand (PD1/PDL1) and cytotoxic T-lymphocyte-associated protein 4(CTLA4) has emerged as new therapeutic targets in cancer. However, their efficacy has been limited due to resistance. A new- checkpoint V-domain Ig-containing suppressor of T cell activation (VISTA) has appeared, but the use of its inhibition effect in combination with antibodies targeting PDL1/PD1and CTLA4 has not been reported in ovarian cancer.

Methods

In this study, we investigated the expressions of VISTA, CTLA4, and PDL1 using immunohistochemistry (IHC)on 135 Formalin-Fixed Paraffin-Embedded (FFPE)tissue samples of High-grade serous carcinoma (HGSOC). VISTA, CTLA4, PDL1, PD1, CD8, CD4, and FOXP3 mRNA extracted from 429 patients with ovarian cancer in the Cancer Genome Atlas (TCGA) database was included as a validation cohort. Correlations between these checkpoints, tumor-infiltrating- lymphocytes (TILs), and survival were analyzed.

Results and discussion

CTLA4 was detectable in 87.3% of samples, VISTA in 64.7%, PD1 in 56.7%, and PDL1 in 48.1%. PDL1 was the only tested protein associated with an advanced stage (p=0.05). VISTA was associated with PDL1, PD1, and CTLA4 expressions (p=0.005, p=0.001, p=0.008, respectively), consistent with mRNA level analysis from the TCGA database. Univariate analyses showed only VISTA expression (p=0.04) correlated with overall survival (OS). Multivariate analyses showed that VISTA expression (p=0.01) and the coexpression of VISTA+/CTLA4+/PD1+ (p=0.05) were associated with better OS independently of the clinicopathological features. Kaplan-Meier analysis showed that the coexpression of the VISTA+/CTLA4+/PDL1+ and VISTA+/CTLA4+/PD1+ checkpoints on tumor cells (TCs)were associated with OS (p=0.02 and p<0.001; respectively). VISTA+/CTLA4+/PD1+ in TCs and CD4+/CD8+TILswere associated with better 2-yer OS. This correlation may refer to the role of VISTA as a receptor in the TCs and not in the immune cells. Thus, targeting combination therapy blocking VISTA, CTLA4, and PD1 could be a novel and attractive strategy for HGSOC treatment, considering the ambivalent role of VISTA in the HGSOC tumor cells.

Abstract P6-10-15: Targeting MARCKS in inflammatory breast cancer increased paclitaxel sensitivity

Background. Because of its high metastatic potential, inflammatory breast cancer (IBC) is the most lethal and aggressive form of breast cancer. We previously demonstrated that Myristoylated Alanine-Rich C Kinase Substrate (MARCKS) protein overexpression was associated with shorter metastasis-free survival (MFS) in IBC patients, but not in non-IBC (nIBC) patients. However, the mechanism of action of MARCKS and its particular association to poorer outcome in IBC compared to nIBC are poorly understood. Methods. We evaluated in vitro the inhibitory effect of MPS (MARCKS phosphorylation site domain), a peptide targeting MARCKS phosphorylation site domain (PSD) in single and in combination with paclitaxel treatment, on cell proliferation and cell motility in two cell lines of different phenotype (SUM149 for IBC and MDA-MB-231 for nIBC), as well as its distinct molecular mechanisms of action. We also assessed the clinical relevance of the protein expression of MARCKS and phosphatase and tensin homolog (PTEN) in a large series of IBC vs. nIBC patients. Results. In vitro, the treatment with MPS peptide impaired cell proliferation, migration, and invasion in SUM149 compared to MDA-MB-231 cells. More important, MARCKS inhibition increased paclitaxel sensitivity when using combination therapy in SUM149 cells compared to MDA-MB-231 cells. Interestingly, we could partially explain this specific inhibitory effect in IBC cells using western blot: MARCKS inhibition in single and in combination induced up and downregulation of the PTEN/AKT signaling pathway respectively in IBC compared to nIBC cells. Importantly, a negative correlation of MARCKS and PTEN was only found in the clinical IBC samples (180 patients) compared to nIBC samples (355 patients). More importantly, the group of patients with negative MARCKS and positive PTEN protein expression was associated to better 5-year MFS only in IBC patients. Conclusion. These results indicate two major findings: first, the important prognostic value of the negative correlation of MARCKS and PTEN expression in IBC patients, and second the specific role of MARCKS in regulating different downstream pathways and increasing the paclitaxel response in combination treatment in IBC compared to non-IBC. They suggest a potential IBC-specific targetable biomarker, the inhibition of which might impair disease aggressiveness and perhaps enhance patients’ survival.

Citation Format: Maroua Manai, Ines Bini, Pascal Finetti, Haifa Bichiou, Carolina Reduzzi, Naziha Ben Hamida, Marc Lopez, Khaled Rahal, Karima Mrad, Mohamed Manai, Massimo Cristofanilli, Hamouda Boussen, Raoudha Doghri, Maher Kharrat, François Bertucci. Targeting MARCKS in inflammatory breast cancer increased paclitaxel sensitivity [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-10-15.

VISTA+/CD8+ status correlates with favorable prognosis in Epithelial ovarian cancer

Immunotherapy by blocking immune checkpoint regulators has emerged as a new targeted therapy for some cancers. Among them V-domain Ig suppressor of Tcell activation (VISTA) which is identified as a novel checkpoint regulator in ovarian cancer. This study aimed to investigate the VISTA role in Epithelial ovarian cancer (EOC), and its relationship with tumor-infiltrating lymphocytes (TILs) markers and its prognostic value. The expression of VISTA, CD3, CD8, CD4, FOXP3, and CD56 was assessed in 168 EOC tissue microarrays (TMA) by immunohistochemistry (IHC). In addition, associations between VISTA, TILs, clinicopathological variables, and overall survival (OS) were analyzed. VISTA expression in IGRov1 cells, as well as in PBMC of EOC patient, was evaluated by western blot. VISTA expression was detected in 64,28% of tissues, among which 42.3% were positive for tumor cells (TCs), and 47,9% were positive for immune cells (ICs). In univariate analysis, VISTA expression was significantly associated with a high density of TILs:CD3+ (p = 0,001), CD4+ (p = 0,002) and CD8+ (p≤0,001), in ICs but not in TCs. In terms of OS, multivariate analysis showed a significant association between the high density of CD8+ TILs and VISTA positive staining in ICs (p = 0,044), but not in TCs (p = 0,108). Kaplan-Meier curves demonstrated no correlation between VISTA expression and prolonged OS in both ICs (p = 0,841) and TCs (p = 0,090). Classification of EOC tumor microenvironment based on VISTA and CD8+TILs expression, demonstrated four immune subtypes: VISTA+/CD8+, VISTA+/CD8-, VISTA-/CD8+ and VISTA-/CD8-. The dual positive VISTA+/CD8+ subtype was significantly associated with prolonged OS in both TCs and ICs (p = 0,012 and p≤0,01, respectively), whereas patients with VISTA+/CD8- had the worst OS. Our results showed that VISTA is highly expressed in the IGRov1 cell line and LT-CD8 from a patient with EOC. Our results highlighted the association of VISTA expression and CD8+ TILs in EOC, with prolonged OS in patients with VISTA+/CD8+ and proposed VISTA as a potential immunotherapeutic target in EOC.

MARCKS as a Potential Therapeutic Target in Inflammatory Breast Cancer

Inflammatory breast cancer (IBC) is the most pro-metastatic form of breast cancer (BC). We previously demonstrated that protein overexpression of Myristoylated Alanine-Rich C Kinase Substrate (MARCKS) protein was associated with shorter survival in IBC patients. MARCKS has been associated with the PI3K/AKT pathway. MARCKS inhibitors are in development. Our objective was to investigate MARCKS, expressed preferentially in IBC that non-IBC (nIBC), as a novel potential therapeutic target for IBC. The biologic activity of MPS, a MARCKS peptide inhibitor, on cell proliferation, migration, invasion, and mammosphere formation was evaluated in IBC (SUM149 and SUM190) and nIBC (MDA-MB-231 and MCF7) cell lines, as well as its effects on protein expression in the PTEN/AKT and MAPK pathways. The prognostic relevance of MARCKS and phosphatase and tensin homolog (PTEN) protein expression as a surrogate marker of metastasis-free survival (MFS) was evaluated by immunohistochemistry (IHC) in a retrospective series of archival tumor samples derived from 180 IBC patients and 355 nIBC patients. In vitro MPS impaired cell proliferation, migration and invasion, and mammosphere formation in IBC cells. MARCKS inhibition upregulated PTEN and downregulated pAKT and pMAPK expression in IBC cells, but not in nIBC cells. By IHC, MARCKS expression and PTEN expression were negatively correlated in IBC samples and were associated with shorter MFS and longer MFS, respectively, in multivariate analysis. The combination of MARCKS-/PTEN+ protein status was associated with longer MFS in IBC patient only (p = 8.7 × 10⁻³), and mirrored the molecular profile (MARCKS-downregulated/PTEN-upregulated) of MPS-treated IBC cell lines. In conclusion, our results uncover a functional role of MARCKS implicated in IBC aggressiveness. Associated with the good-prognosis value of the MARCKS-/PTEN+ protein status that mirrors the molecular profile of MPS-treated IBC cell lines, our results suggest that MARCKS could be a potential therapeutic target in patients with MARCKS-positive IBC. Future preclinical studies using a larger panel of IBC cell lines, animal models and analysis of a larger series of clinical samples are warranted in order to validate our results.

FOXP3+/CD68+ ratio within the tumor microenvironment may serve as a potential prognostic factor in classical Hodgkin lymphoma

Classical Hodgkin lymphoma (CHL) is characterized by extensive inflammatory immune cells, which predict the disease prognosis. Therefore, this study aimed to explore the significance of different tumor-infiltrated immune cells and subpopulation ratios observed in the tumor microenvironment of CHL, particularly relating to the disease's prognosis-focusing on overall survival (OS) and event-free survival (EFS). Utilizing immunohistochemistry, the quantification and exploration of selected immune cells' subsets, including CD3+, CD4+, CD8+, FOXP3+, CD20+, and CD68+ were conducted on 102 histological samples with primary CHL. Eosinophils were pathologically assessed. Besides, we determined the ratios between different tumor-infiltrated immune cells for each patient. Kaplan-Meier method and Cox regression modeling were used for survival analysis. We demonstrated that among all ratios and immune cells individually, only a higher FOXP3+/CD68+ ratio (≥1.36 cutoff) displayed a tendency towards a favorable OS (p = 0.057, HR = 0.43 [0.18-1.02]) and EFS (p = 0.067, HR = 0.44 [0.18-1.06]) using Cox regression modeling. Moreover, the Kaplan-Meier method showed an association of a higher FOXP3+/CD68+ ratio with a longer 5-years OS (p = 0.037) and a tendency to a better EFS (p = 0.051); however, neither the combined FOXP3+ and CD68+ nor FOXP3+ or CD68+ separately was correlated to the CHL survival. Together, these results demonstrated that the FOXP3+/CD68+ ratio could predict the outcomes of CHL, providing more informative significance than FOXP3+ and CD68+ combined or FOXP3+ and CD68+ individually and might be a potential indicator of risk stratification, which has an important value for guiding the clinical treatment.

Diversity of rhizospheric and endophytic bacteria isolated from dried fruit of Ficus carica

There is currently an increasing demand for the characterization of endophytic bacteria isolated from different parts of plants (rhizosphere, roots, fruit, leaf) in order to improve the organic agriculture practices. The current research was performed to identify both rhizospheric bacteria isolated from the rhizosphere of Ficus carica in three different sites in the north of Tunisia and endophytic bacteria isolated from dried figs. We then characterized them for a diversity of plant growth-promoting (PGP) activities. A collection of 120 isolates from rhizospheric soil and 9 isolates from dried figs was obtained and purified. 16SrDNA gene amplification of rhizospheric bacteria revealed significant diversity and allowed for the assigning of the isolates to 6 phyla: Gammaproteobacteria, Alphaproteobacteria, Betaproteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. Representative strains of the collection (90 strains) were tested for numerous PGP activities and resistance to abiotic stresses. The most common PGP trait for all bacteria from the three regions was siderophore production (62%), followed by cellulase (38%), then protease activity (37%), then by lipases activity (17%) and lastly by solubilization of phosphates (9%). Twenty -three strains that showed most PGP traits were selected, 8 strains presented 12 or more, and 15 strains displayed between 7 and 11 of 17 PGP activities. The majority of the isolates manifested a possible adaptation to abiotic stress and unfavorable environments. PCR-DGGE analysis of soil rhizosphere of the three sites allowed also for the acquisition of a Cluster analysis of rhizospheric bacterial communities. Our current study identified and characterized for the first time in Tunisia rhizospheric and endophytic bacteria from dried fruit of Ficus carica.

Menin inhibition suppresses castration-resistant prostate cancer and enhances chemosensitivity

Disease progression and therapeutic resistance of prostate cancer (PC) are linked to multiple molecular events that promote survival and plasticity. We previously showed that heat shock protein 27 (HSP27) acted as a driver of castration-resistant phenotype (CRPC) and developed an oligonucleotides antisense (ASO) against HSP27 with evidence of anti-cancer activity in men with CRPC. Here, we show that the tumor suppressor Menin (MEN1) is highly regulated by HSP27. Menin is overexpressed in high-grade PC and CRPC. High MEN1 mRNA expression is associated with decreased biochemical relapse-free and overall survival. Silencing Menin with ASO technology inhibits CRPC cell proliferation, tumor growth, and restores chemotherapeutic sensitivity. ChIP-seq analysis revealed differential DNA binding sites of Menin in various prostatic cells, suggesting a switch from tumor suppressor to oncogenic functions in CRPC. These data support the evaluation of ASO against Menin for CRPC.

Overexpression of Annexin A1 Is an Independent Predictor of Longer Overall Survival in Epithelial Ovarian Cancer

BACKGROUND

Epithelial ovarian cancer (EOC) is the major gynecological cause of cancer deaths. Annexin A1 (ANXA1) protein has been implicated in the aggressiveness of several cancer types.

MATERIALS AND METHODS

This study retrospectively assessed ANXA1 expression in epithelial cells of 156 pre-chemotherapy EOC samples and 34 normal ovarian samples from patients treated at Salah Azaiez Institute. Using immunohistochemistry, ANXA1 expression was compared in normal versus cancer samples; correlations with clinicopathological features, including overall survival, were sought.

RESULTS

Fifty-two percent of tumor samples showed epithelial ANXA1 staining versus only 26% of normal samples (Fisher's exact test, p=0.00794). Epithelial ANXA1 expression was correlated with better overall survival in both univariate and multivariate analyses.

CONCLUSION

The possible contribution of ANXA1 overexpression to EOC outcome may be relevant to therapeutic strategies.

Adolescents and young adults with classical Hodgkin lymphoma in northern Tunisia: insights from an adult single-institutional study

PURPOSE

The aim of this study was to extensively describe the epidemiological, clinical and therapeutic outcomes of adolescents and young adults (AYA) population with classical Hodgkin Lymphoma (cHL). Then, a comparison between AYAs and adults and between the subgroups of AYAs treated with the same adult protocol was accomplished to further inform on optimal therapy approach of choice for adolescent patients.

MATERIAL AND METHODS

In this mono-centric, retrospective study, we reviewed the medical records. We analyzed 112 consecutive North Tunisian patients, including 66 AYAs (15 to 39 years) and 46 adults (≥40years) affected by cHL treated from 2000 to 2015 at Salah Azaiez Institute. Then, we performed a comparative analysis between AYA and 46 adult patients and a subgroup analysis between adolescents and young adults. All patients were treated according to the national protocol for HL, edited by the Tunisian Society of Hematology. The treatment included chemotherapy and involved-field radiotherapy (RT) at a dose of 20 or 30 Grays (Gy) for responders and 36Gy for non-responders.

RESULTS

AYA patients presented with adverse features with nodular sclerosis subtype (p=3.88×10^-02) and mediastinal mass involvement (p=9.40×10^-04). At a median follow-up of 51 and 32 months for AYAs and adults, respectively, no statistical difference in terms of 3 and 5-years overall survival (OS) and event-free survival (EFS) was shown. Using the Kaplan-Meier method, in AYAs, the ABVD regimen has an impact on 3-years EFS (p=4.63×10^-02). The 36Gy RT was associated with the best 3-years EFS (p=9.24×10^-03). Besides, AYA patients with advanced-stage had the worst 3-years OS (76%) (p=2.41×10^-02). Although the adolescents and young adults shared similar clinical presentation, we noted that the adolescent group had the worst 3-years EFS (48%), but the best 3-years OS (91%). We identified 15% of primary refractory patients and a rate of toxicity of 5.3% in AYA.

CONCLUSION

The treatment approach used is well tolerated by adult patients. However, the AYA patients and particularly adolescent subgroup had more advanced disease at diagnosis and should be treated more intensively in dedicated units. RT dose<36Gy and ABVD chemotherapy were associated with lower EFS in this population.

Inflammatory breast cancer in 210 patients: A retrospective study on epidemiological, anatomo-clinical features and therapeutic results

To report epidemiological and anatomo-clinical features within a retrospective series of inflammatory breast cancer and to evaluate prognostic factors. This retrospective study included 210 Tunisian patients presenting a clinically diagnosed IBC, treated at the Institute Salah Azaiez (ISA) of Tunis, Tunisia, from 2008 to 2013. We collected data on epidemiology, anatomo-clinical and biological features and histologic response to neoadjuvant therapy. Overall and disease-free survivals were calculated by Kaplan-Meier method and compared by log-rank tests and Cox's models were used to identify prognostic factors impacting survival. The 210 IBC patients had a median age of 42 years (24-62) and 15% of them were aged less than 35 years. Mean age at menarche was 13 years and 45% had their 1st childbirth before 23 years. On histology, grades III represented 42% of cases, hormone receptors were negative in 59%, HER2 over-expressed in 32, 25% of our IBC cases had a triple negative profile and Ki-67 was >20% in 53% of cases. High pathological grade III was significantly correlated to TN subtype (58%) (Fisher's exact test, P=7.5×10^-3). Further, high Ki-67 expression (>20%) was evident in the TN subtype (84%) (Fisher's exact test, P=3.7×10^-4). After neoadjuvant therapy (and trastuzumab in 88 and 69% of HER2+ patients, respectively), we observed 49% of objective clinical responses and 35% of pathological complete response (pCR) and >3 axillary lymph nodes were invaded on a resected tumor in 55% of cases. Overall survival (OS) was associated with age at menarche (Wald-test, P=2.2×10^-2) and metastases at diagnosis (Wald-test, P=2.4×10^-2). Reaching a pCR was correlated with a better metastasis-free survival (MFS), (Fisher's exact test, P=3.6×10^-2).

MARCKS protein overexpression in inflammatory breast cancer

Background

Inflammatory breast cancer (IBC) is the most aggressive form of locally-advanced breast cancer. Identification of new therapeutic targets is crucial. We previously reported MARCKS mRNA overexpression in IBC in the largest transcriptomics study reported to date. Here, we compared MARCKS protein expression in IBC and non-IBC samples, and searched for correlations between protein expression and clinicopathological features.

Results

Tumor samples showed heterogeneity with respect to MARCKS staining: 18% were scored as MARCKS-positive (stained cells ≥ 1%) and 82% as MARCKS-negative. MARCKS expression was more frequent in IBC (36%) than in non-IBC (11%; p = 1.4E−09), independently from molecular subtypes and other clinicopathological variables. We found a positive correlation between protein and mRNA expression in the 148/502 samples previously analyzed for MARCKS mRNA expression. MARCKS protein expression was associated with other poor-prognosis features in the whole series of samples such as clinical axillary lymph node or metastatic extension, high pathological grade, ER-negativity, PR-negativity, HER2-positivity, and triple-negative and HER2+ statutes. In IBC, MARCKS expression was the sole tested variable associated with poor MFS.

Materials and Methods

We retrospectively analyzed MARCKS protein expression by immunohistochemistry in 502 tumors, including 133 IBC and 369 non-IBC, from Tunisian and French patients. All samples were pre-therapeutic clinical samples. We searched for correlations between MARCKS expression and clinicopathological features including the IBC versus non-IBC phenotype and metastasis-free survival (MFS).

Conclusions

MARCKS overexpression might in part explain the poor prognosis of IBC. As an oncogene associated with poor MFS, MARCKS might represent a new potential therapeutic target in IBC.

Clinicopathologic and Prognostic Significance of Metalloproteinase Tissue Inhibitor-2 Promoters in Tunisian Colorectal Cancer: A Case-Control Study

Tissue inhibitors of metalloproteinases (TIMPs) appear to affect many aspects of cancer biology, playing a crucial role in cell signaling by regulating cell growth, apoptosis, invasion, metastasis, angiogenesis, and genomic instability. In the present study, we investigate whether TIMP-2 SNP, TIMP-2 mRNAs, and TIMP-2 protein is associated with susceptibility to colorectal cancer (CRC) in Tunisian population. Taqman and DNA sequencing techniques were used for genotyping, TIMP-2 expression of each genotype was analyzed using semiquantitative RT-PCR and TIMP-2 protein expression was analyzed using immunohistochemistry staining. Our results showed that significantly elevated CRC risk was found in individuals with CC genotype (odds ratio 1.959; 95% confidence interval, 1.055-3.637). Moreover TIMP-2 mRNA expression in the colorectal cell carcinomas was significantly higher compared with the normal colorectal tissue (0.487±0.015 vs. 0.210±0.013) (P<0.05). In addition, serum levels of TIMP-2 were significantly lower in CRC patients than in adenoma patients (P=0.01) and healthy controls (P=0.003). Serum levels of TIMP-2 correlated significantly with tumor stage and TNM stage and were the lowest in CRC patients with stage D,T4,(N1,N2,N3),M(+). In conclusion, our study demonstrate for the first time the distribution and the clinical significance of TIMP-2 promoter polymorphisms, mRNA, protein expression, and serum level in CRC Tunisian patients suggesting that the genotyping and serum level of TIMP-2 as potential markers for susceptibility to CRC will allow a precise and early identification of individuals at high risk and will aid the design of therapeutic modalities and evaluation of treatment outcome.

Prognostic impact of polymorphism of matrix metalloproteinase-2 and metalloproteinase tissue inhibitor-2 promoters in breast cancer in Tunisia: case-control study

Matrix metalloproteinases (MMPs) are proteolytic enzymes that play important roles in tumor invasion and metastasis by degrading extracellular matrix components. Genetic variations in promoter regions of MMP genes, affecting their expression, have been associated with susceptibility to cancers. The aim of this study was to investigate the susceptibility and prognostic implications of the matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) polymorphism in Tunisian breast cancer patients. MMP-2 genotypes were determined by real-time polymerase chain reaction (RT-PCR), and TIMP-2 genotypes were identified using a PCR-restriction fragment length polymorphism (RFLP) method in 210 breast cancer patients and 250 frequency-matched control women. Association of the clinicopathological parameters and the genetic markers with risk of breast cancer was assessed using univariate analyses. We found that the variant MMP-2 genotype (-1306CT or TT) was associated with substantially reduced risk of breast cancer [odds ratio (OR), 0.49; 95 % confidence interval (95 % CI), 0.033-0.73], compared with the CC genotype. For TIMP-2, a moderately reduced risk of the cancer (OR, 0.57; 95 % CI, 0.37-0.87) was also associated with the variant allele (-418GC or CC), compared with the GG common allele. Furthermore, polymorphisms in both genes seem to have additive effects and the highest risk for breast cancer has been observed in those with MMP-2 CC genotype and TIMP-2 GC or CC genotype (p = 0.006). A significant association was also found between the CC genotype and the aggressive forms of breast cancer as defined by advanced stages at the time of diagnosis and metastasis. This is the first report on the association of MMP-2 and TIMP-2 gene polymorphisms in breast cancer in Tunisian population. Our results suggest that the presence of the variant allele in the promoter of MMP-2 or TIMP-2 may be a protective factor for the development of breast cancer.

Somatic molecular changes and histo-pathological features of colorectal cancer in Tunisia

AIM: To determine correlations between family history, clinical features and mutational status of genes involved in the progression of colorectal cancer (CRC).

METHODS: Histo-pathological features and molecular changes [KRAS, BRAF and CTNNB1 genes mutations, microsatellite instability (MSI) phenotype, expression of mismatch repair (MMR) and mucin (MUC) 5AC proteins, mutation and expression analysis of TP53, MLH1 promoter hypermethylation analysis] were examined in a series of 51 unselected Tunisian CRC patients, 10 of them had a proven or probable hereditary disease, on the track of new tumoral markers for CRC susceptibility in Tunisian patients.

RESULTS: As expected, MSI and MMR expression loss were associated to the presence of familial CRC (75% vs 9%, P < 0.001). However, no significant associations have been detected between personal or familial cancer history and KRAS (codons 12 and 13) or TP53 (exons 4-9) alterations. A significant inverse relationship has been observed between the presence of MSI and TP53 accumulation (10.0% vs 48.8%, P = 0.0335) in CRC tumors, suggesting different molecular pathways to CRC that in turn may reflect different environmental exposures. Interestingly, MUC5AC expression was significantly associated to the presence of MSI (46.7% vs 8.3%, P = 0.0039), MMR expression loss (46.7% vs 8.3%, P = 0.0039) and the presence of familial CRC (63% vs 23%, P = 0.039).

CONCLUSION: These findings suggest that MUC5AC expression analysis may be useful in the screening of Tunisian patients with high risk of CRC.

Identification and antifungal susceptibility of a large collection of yeast strains isolated in Tunisian hospitals

In this study, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used as a rapid method to identify yeasts isolated from patients in Tunisian hospitals. When identification could not be exstablished with this procedure, sequencing of the internal transcribed spacer with 5.8S ribosomal DNA (rDNA) (ITS1-5.8S-ITS2) and D1/D2 domain of large-subunit (LSU rDNA) were employed as a molecular approach for species differentiation. Candida albicans was the dominant species (43.37% of all cases), followed by C. glabrata (16.55%), C. parapsilosis (13.23%), C. tropicalis (11.34%), C. dubliniensis (4.96%), and other species more rarely encountered in human diseases such as C. krusei, C. metapsilosis, C. lusitaniae, C. kefyr, C. palmioleophila, C. guilliermondii, C. intermedia, C. orthopsilosis, and C. utilis. In addition, other yeast species were obtained including Saccharomyces cerevisiae, Debaryomyces hansenii (anamorph known as C. famata), Hanseniaspora opuntiae, Kodamaea ohmeri, Pichia caribbica (anamorph known as C. fermentati), Trichosporon spp. and finally a novel yeast species, C. tunisiensis. The in vitro antifungal activities of fluconazole and voriconazole were determined by the agar disk diffusion test and Etest, while the susceptibility to additional antifungal agents was determined with the Sensititre YeastOne system. Our results showed low incidence of azole resistance in C. albicans (0.54%), C. tropicalis (2.08%) and C. glabrata (4.28%). In addition, caspofungin was active against most isolates of the collection with the exception of two K. ohmeri isolates. This is the first report to describe caspofungin resistant isolates of this yeast.

Tumor multiplicity is an independent prognostic factor of non-muscle-invasive bladder cancer treated with Bacillus Calmette-Guerin immunotherapy

BACKGROUND

Bacillus Calmette-Guerin (BCG) immunotherapy is regarded as the current treatment of choice for non muscle invasive bladder cancer (NMIBC), though its efficacy is limited by high recurrence and progression rate. Identification of factor prognosticators that might be helpful in discriminating between responders and nonresponders to BCG treatment is therefore of major clinical importance. The aim of this study is to evaluate the prognostic factors of recurrence after intravesical adjuvant BCG immunotherapy in patients with NMIBC.

METHODS

we retrospectively reviewed the clinical and pathologic data of primary NMIBC from 112 patients who were treated with transurethral resection followed by BCG-immunotherapy. Time follow-up was 30 months. The prognostic significance of tumor stage, grade, multiplicity, age, sex and smoking in determining the risk for recurrence after BCG therapy was studied with both univariate and multivariate methods of analysis.

RESULTS

According to univariate analysis of the prognostic significance for tumor stage, grade, loci number, sex, age and smoking, the pT1 stage and multiplicity seem to be associated in a statistically significant manner with higher risk for recurrence (P = 0.009, P = 0.011, respectively). In the other hand, multivariate analysis showed that only multiplicity was an independent significant prognosticator.

CONCLUSION

Significant independent predictor for recurrence was multiplicity which offers important clinical information and may be a useful tool in the selection of suitable candidates for BCG-immunotherapy.

Paenibacillus marinum sp. nov., a thermophilic xylanolytic bacterium isolated from a marine hot spring in Tunisia

Among a large collection of Tunisian hot springs bacterial isolates a bacterial strain, THE22(T) , with xylanolytic properties was identified. The bacterium was isolated from a natural hot spring "Ain Echefa" at Mediteranean sea (Korbous, North-Eastern Tunisia). The novel strain was Gram positive, spore-forming, rod-shaped, facultatively anaerobic and grew optimally under conditions of 55 °C, 1% (w/v) NaCl and pH 7-8. The 16S rRNA gene sequence analysis showed that strain THE22(T) fell within the radiation of the cluster comprising Paenibacillus species with Paenibacillus phyllosphaerae PALXIL04(T) as the closest phylogenetic neighbour (95.8%). The predominant components in the fatty methyl ester profile were iso-C16:0 (34.46%), C16:0 (19.64%), anteiso-C15:0 (19.18%) and anteiso-C17:0 (18.11%). The major respiratory quinone was menaquinone-7 (MK-7). The diamino acid found in the cell-wall peptidoglycan was meso-diaminopimelic acid. The base composition of DNA was 56 mol%. Based on the polyphasic taxonomic data, strain THE-22(T) (=DSM 18499(T) = LMG 23758(T) ) was recognized as a novel species within the genus Paenibacillus. The name Paenibacillus marinum sp. nov. is proposed.

Prognostic value of Bcl-2 and Bax tumor cell expression in patients with non muscle-invasive bladder cancer receiving bacillus Calmette-Guerin immunotherapy

Apoptosis is the distinctive form of programmed cell death that complements cell proliferation in maintaining normal tissue homeostasis. The significance of constitutive apoptosis in the recurrence of Non Muscle Invasive Bladder Cancer has yet to be investigated. The aim of this study is to investigate the prognostic significance of Bax and Bcl-2 in terms of recurrence after BCG immunotherapy. Immunohistochemical analysis was performed on frozen biopsies to evaluate bcl-2 and Bax proteins expression in 28 cases of NMIBC. All patients with confirmed NMIBC were treated with intravesical BCG-immunotherapy. The follow up was performed for 26 months. The correlation between clinicopathological, immunohistochemical data and the response to BCG therapy was performed. Univariate analysis showed that, PT1 stage, High grade and Bax expression increased significantly the risk of recurrence (P = 0.015, P = 0.015 and P= 0.034 respectively). In addition, multivariate analysis selected the model involving stage, age, Bax and Bcl-2 expression as the best independent variables of recurrence. In conclusion, the expression of Bcl-2 and Bax in NMIBC could have a prognostic value in assessing the risk of recurrence after BCG immunotherapy. These findings require further investigations on larger cohort in order to ascertain new molecular markers of the response to BCG immunotherapy.

Interactive effects of pH and temperature on the bacteriocin stability by response surface analysis

The combined influence of pH and temperature on bacteriocins produced by three lactic acid bacteria, Pediococcus pentosaceus MMZ26, Enterococcus faecium MMZ17 and Lactococcus lactis MMZ25, isolated from Tunisian traditional dry fermented meat was studied using a second order orthogonal factorial design and response-surface methodology (RSM). This method allows estimating the interactive effects of pH and temperature on the stability of each bacteriocin. The high heat stability of the three bacteriocins was demonstrated, with optimum values at light acidic pH around 5.0, temperature below 90 degrees C and short incubation times. This study contributes to a better understanding of relation between bacteriocins production and stability in order to enhance their, in situ, application as a food and feed biopreservative in fermented and/or heated food products.

Identification of lactobacilli residing in chicken ceca with antagonism against Campylobacter

Bacteriocins produced by Lactobacillus salivarius have been recently recognized as a natural means to control Campylobacter and Salmonella in live poultry. This finding is of relevance since Campylobacter jejuni and Campylobacter coli are the predominant species isolated from poultry that are associated with human campylobacteriosis. In the present work, lactic acid bacteria (LAB) isolated from the cecum of twenty Tunisian chickens were identified and those isolates with antagonism against Campylobacter were further characterized. Following their preliminary confirmation as LAB, 150 strains were identified by combining morphological criteria, biochemical tests, and molecular methods, the latter inluding intergenic 16S- 23S PCR, specific lactobacilli PCR, and a biphasic approach. Most of the LAB isolated belonged to the genus Lactobacillus, among them Lb. sakei (33.3%), Lb. salivarius (19.4%), Lb. reuteri (8.6%), and Lb. curvatus (8.6%). The other LAB strains included those of the genus Weissella (16.7%), Enterococcus faecalis (5.3%), Leuconostoc mesenteroides (2.7%), Lactococcus graviae (2.7%), and Streptococcus sp. (2.7%). The Lactobacilli strains were tested for their antagonism against C. jejuni and C. coli. The activity of three of them, Lb. salivarius SMXD51, Lb. salivarius MMS122, and Lb. salivarius MMS151, against the aforementioned target strains could be ascribed to the production of bacteriocins.

Characterization of Deinococcus sahariens sp. nov., a radiation-resistant bacterium isolated from a Saharan hot spring

An ultraviolet-radiation-resistant, Gram-positive, orange-pigmented, thermophilic and strictly aerobic cocci was isolated from Saharan water hot spring in Tunisia. The newly isolated bacterium, designated HAN-23(T), was identified based on polyphasic taxonomy including genotypic, phenotypic and chemotaxonomic characterization. Phylogenetic analysis based on 16S rRNA gene sequences placed this strain within Deinococcus genus. However, strain HAN-23(T) is different from recognized species of the genus Deinococcus, showing less than 94.0% similarity values to its closest relatives. The predominant cellular fatty acids determined by gas chromatography were iso-C(15:0), iso-C(17:0) and iso C(17:1) ω9c. The major respiratory quinone was MK-8. The DNA G + C content was 66.9 mol%. DNA-DNA hybridization measurements revealed low DNA relatedness (6%) between the novel isolate and its closest neighbor, the type strain Deinococcus geothermalis DSM 11300. On the basis of the phenotypic, chemotaxonomic and phylogenetic data, strain HAN-23(T) represents a novel species of the genus Deinococcus, for which the name Deinococcus sahariens sp. nov. is proposed, the type strain being HAN-23(T) (=DSM 18496(T); LMG 23756(T)).

Lynch syndrome in Tunisia: first description of clinical features and germline mutations

PURPOSE

High rates of early colorectal cancers (CRC) are observed in Tunisia suggesting genetic susceptibility. Nevertheless, up to now, no molecular study has been performed in the Tunisian population. In our research, we evaluated the clinical characteristics of Tunisian families suspected of Lynch syndrome and the contribution of DNA mismatch repair (MMR) genes.

METHODS

Thirty-one unrelated families suspected of Lynch syndrome were studied. Probands were tested for the presence of germline mutations in the MMR genes MLH1, MSH2, MSH6 and in MUTYH. Available tumours were analysed for microsatellite instability and expression of MMR proteins. Detailed family and medical histories were collected.

RESULTS

A total of 134 cancers were noted in the 31 families, the most frequent type of cancer corresponding to CRC (69%), followed by uterine cancer (7.5%). Germline mutations were identified in 11 (35.5%) families (six MSH2, five MLH1, including seven novel mutations), seven of which fulfilled the Amsterdam criteria (sensitivity, 63.6%; positive predictive value, 58.3%). Noteworthy, germline mutations were detected in 52.6% of male patients tested, but in only 8.3% of females (p = 0.02). Moreover, CRC were essentially left sided in families without detected mutation (p = 0.017). Ages of onset of cancers and tumour spectrum were very similar in families with or without MMR germline mutation, contrasting with previous studies performed in other populations.

CONCLUSIONS

MMR genes contribute significantly to CRC susceptibility in the Tunisian population. However, the cause of early CRC susceptibility remains unknown in most cases, especially in women and in patients with early left colon or rectal cancer.

Two distinct regions of calponin share common binding sites on actin resulting in different modes of calponin-actin interaction

Calponins are a small family of proteins that alter the interaction between actin and myosin II and mediate signal transduction. These proteins bind F-actin in a complex manner that depends on a variety of parameters such as stoichiometry and ionic strength. Calponin binds G-actin and F-actin, bundling the latter primarily through two distinct and adjacent binding sites (ABS1 and ABS2). Calponin binds other proteins that bind F-actin and considerable disagreements exist as to how calponin is located on the filament, especially in the presence of other proteins. A study (Galkin, V.E., Orlova, A., Fattoum, A., Walsh, M.P. and Egelman, E.H. (2006) J. Mol. Biol. 359, 478-485.), using EM single-particle reconstruction has shown that there may be four modes of interaction, but how these occur is not yet known. We report that two distinct regions of calponin are capable of binding some of the same sites on actin (such as 18-28 and 360-372 in subdomain 1). This accounts for the finding that calponin binds the filament with different apparent geometries. We suggest that the four modes of filament binding account for differences in stoichiometry and that these, in turn, arise from differential binding of the two calponin regions to actin. It is likely that the modes of binding are reciprocally influenced by other actin-binding proteins since members of the alpha-actinin group also adopt different actin-binding positions and bind actin principally through a domain that is similar to calponin's ABS1.

The gelsolin:calponin complex nucleates actin filaments with distinct morphologies

Gelsolin and calponin are cytoskeletal and signalling proteins that form a tight 1:1 complex (GCC). We show that calponin within the GCC inhibits the rate of gelsolin mediated nucleation of actin polymerization. The actin-binding function of calponin is ablated within the GCC as the actin-binding site overlaps with one of the gelsolin binding sites. The structure of filaments that result from nucleation by GCC are different to those nucleated by gelsolin alone in that they are longer, loosely bundled and stain heterogeneously with phalloidin. GCC nucleated filaments appear contorted and wrap around each to form the loose bundles.

Polyphasic taxonomic studies of lactic acid bacteria associated with Tunisian fermented meat based on the heterogeneity of the 16S-23S rRNA gene intergenic spacer region

The objective of this work was to investigate the structure and diversity of lactic acid bacteria (LAB) communities in traditionally fermented meat collected from different areas of Tunisia. A polyphasic study, which involves phenotypic tests and ribosomal DNA-based techniques, was used to identify Gram-positive and catalase-negative isolates. PCR amplification of the 16S-23S rDNA ISR of 102 isolates and other reference LAB strains gave (1) one type of rrn operon (M-ISR) for lactococci, (2) two types of rrn operon (S-ISR and M-ISR) for enterococci, (3) two types of rrn operon (S-ISR and L-ISR) for Lactobacilli, and (4) three PCR amplicons (S-ISR, M-ISR, and L-ISR) obtained for Pediococcus spp. and Weissella genus. The clustering and comparison of ISR-RFLP profiles given by the isolates with those given by reference LAB strains, allowed their identification as Lactococcus lactis, Enterococcus faecium, Enterococcus faecalis, Enterococcus sanguinicola, Enterococcus hawaiiensis, Lactobacillus sakei, Lactobacillus curvatus, Lactobacillus plantarum, Lactobacillus alimentarius, Pediococcus pentosaceus, and Weissella confusa. Combined 16S-23S rDNA ISR and RFLP patterns can be considered as a good potential target for a rapid and reliable differentiation between isolates of LAB and provided further information on the organization of their rrn operons.

Identification and characterization of a novel MLH1 genomic rearrangement as the cause of HNPCC in a Tunisian family: evidence for a homologous Alu-mediated recombination

High rates of early colorectal cancers are observed in Tunisia suggesting high genetic susceptibility. Nevertheless, up to now no molecular studies have been performed. Hereditary nonpolyposis colorectal cancer (HNPCC) is the most frequent cause of inherited colorectal cancer. It is caused by constitutional mutations in the DNA mismatch repair (MMR) genes. Here, we investigated a Tunisian family highly suspected of hereditary nonpolyposis colorectal cancer (HNPCC). Six patients were diagnosed with a colorectal or an endometrial cancer at an early age, including one young female who developed a colorectal cancer at 22 years and we tested for germline mutations in MMR genes. MMR genes were tested for rearrangements by MLPA (MLH1, MSH2) and the presence of point mutations by sequencing (MLH1, MSH2, MSH6). Moreover, tumors were analyzed for microsatellite instability and expression of MMR proteins, as well as for somatic rearrangements in MLH1 and MSH2 by MLPA. MMR gene analysis by MLPA revealed the presence of a large deletion in MLH1 removing exon 6. Sequence analysis of the breakpoint region showed that this rearrangement resulted from a homologous unequal recombination mediated by a repetitive Alu sequence. Moreover, tumors harbored biallelic deletion of MLH1 exon 6 and loss of heterozygosity at MLH1 intragenic markers, suggesting duplication of the rearranged allele in the tumor. This germline MLH1 rearrangement was associated to a severe phenotype in this family. This is the first report of a molecular analysis in a Tunisian family with HNPCC.

Two distinct sites of interaction form the calponin: gelsolin complex and two calcium switches control its activity

Gelsolin and calponin are well characterized actin-binding proteins that form a tight gelsolin:calponin complex (GCC). We show here that the GCC is formed through two distinct interfaces. One of these is formed between 144-182 of calponin and 25-150 of gelsolin (G1). The second is a calcium-sensitive site centred on calponin's CH domain, and the C-terminal half of gelsolin (G4-6). The behaviour of this second interface is dependent on the presence of calcium and so it is possible that potential GCC-binding partners may be selected by calcium availability. Actin is one such GCC-binding partner and we show that a larger complex is formed with monomeric actin in calcium. The stoichiometry of this complex is determined to be 1 gelsolin/1 calponin/2 G-actins (GCA(2)). Both actin monomers bind the GCC through gelsolin. Both calponin and gelsolin are reported to play signaling roles in addition to their better-characterized actin-binding properties and it is possible that the GCC regulates both of these functions.

Calponin binds G-actin and F-actin with similar affinity

Calponins are actin-binding proteins that are implicated in the regulation of actomyosin. Calponin binds filamentous actin (F-actin) through two distinct sites ABS1 and ABS2, with an affinity in the low micromolar range. We report that smooth muscle calponin binds monomeric actin with a similar affinity (K(d) of 0.15 microM). We show that the arrangement of binding is similar to that of F-actin by a number of criteria, most notably that the distance between Cys273 on calponin and Cys374 of actin is 29A when measured by fluorescent resonance energy transfer, the same distance as previously reported for F-actin.

A direct interaction with calponin inhibits the actin-nucleating activity of gelsolin

Gelsolin and calponin are well-characterized cytoskeletal proteins that are abundant and widely expressed in vertebrate tissues. It is also becoming apparent, however, that they are involved in cell signalling. In the present study, we show that gelsolin and calponin interact directly to form a high-affinity (K(d)=16 nM) 1:1 complex, by the use of fluorescent probes attached to both proteins, by affinity chromatography and by immunoprecipitation. These methods show that gelsolin can form high-affinity complexes with two calponin isoforms (basic h1 and acidic h3). They also show that gelsolin binds calponin through regions that have been identified previously as being calponin's actin-binding sites. Moreover, gelsolin does not interact with calponin while calponin is bound to F-actin. Reciprocal experiments to find calponin-binding sites on gelsolin show that these are in both the N- and C-terminal halves of gelsolin. Calponin has minimal effects on actin severing by gelsolin. In contrast, calponin markedly affects the nucleation activity of gelsolin. The maximum inhibition of nucleation by gelsolin was 50%, which was achieved with a ratio of two calponins for every gelsolin. Thus the interaction of calponin with gelsolin may play a regulatory role in the formation of actin filaments through modulation of gelsolin's actin-binding function and through the prevention of calponin's actin-binding activities.

Lactococcin MMT24, a novel two-peptide bacteriocin produced by Lactococcus lactis isolated from rigouta cheese

Lactococcin MMT24 is a novel bacteriocin produced by Lactococcus lactis MMT24, a strain isolated from a Tunisian traditional cheese. The bacteriocin shows a narrow antimicrobial activity against closely related lactic acid bacteria. Lactococcin MMT24 is heat resistant, remains active after incubation at pH 3 to 10, lyophilization, long-term storage at -20 degrees C and is sensitive to treatment with proteolytic enzymes. The mode of action of lactococcin MMT24 was identified as bactericidal. Purification of the active compound showed that lactococcin MMT24 consists of two distinct peptides, named pepalpha and pepbeta, whose complementary action is necessary for full antibacterial activity. Optimal antibacterial activity was obtained when the complementary peptides pepalpha and pepbetawere present in equal amounts. Mass spectrometry analysis showed masses of 3765.33 Da and 3255.26 Da for pepalpha and pepbeta, respectively. These molecular masses do not correspond to those of so far described bacteriocins. Addition of 50 nmol l(-1) of lactococcin MMT24 to cells of L. lactis ssp. cremoris ATCC11603 induced increase in the concentration of K+ in supernatant indicating a massive leakage of this ion from the cells. This release was most likely caused by pores formation by the pepalphaand pepbeta peptides in the target bacterial membrane.

Antilisterial activity of lactic acid bacteria isolated from rigouta, a traditional Tunisian cheese

AIMS

Screening for lactic acid bacteria (LAB) producing bacteriocins and other antimicrobial compounds is of a great significance for the dairy industry to improve food safety.

METHODS AND RESULTS

Six-hundred strains of LAB isolated from 'rigouta', a Tunisian fermented cheese, were tested for antilisterial activity. Eight bacteriocinogenic strains were selected and analysed. Seven of these strains were identified as Lactococcus lactis and produced nisin Z as demonstrated by mass spectrometry analysis of the purified antibacterial compound. Polymerase chain reaction experiments using nisin gene-specific primers confirmed the presence of nisin operon. Plasmid profiles analysis suggests the presence of, at least, three different strains in this group. MMT05, the eighth strain of this antilisterial collection was identified, at molecular level, as Enterococcus faecalis. The purified bacteriocin produced by this strain showed a molecular mass of 10 201.33 +/- 0.85 Da. This new member of class III bacteriocins was termed enterocin MMT05.

CONCLUSIONS

Seven lactococcal strains producing nisin Z were selected and could be useful as bio-preservative starter cultures. Additional experiments are needed to evaluate the promising strain MMT05 as bio-preservative as Enterococci could exert detrimental or beneficial role in foods.

SIGNIFICANCE AND IMPACT OF THE STUDY

Only a few antibacterial strains isolated from traditional African dairy products were described. The new eight strains described herein contribute to the knowledge of this poorly studied environment and constitute promising strains for fermented food safety.

Molecular epidemiology and characterization of plasmid-encoded beta-lactamases produced by Tunisian clinical isolates of Salmonella enterica serotype Mbandaka resistant to broad-spectrum cephalosporins

We studied 31 clinical isolates of Salmonella enterica serotype Mbandaka resistant to broad-spectrum cephalosporins and recovered in Tunisia over a 5-year period. The transferability of this resistance was demonstrated by conjugation experiments. Thirty of the 31 isolates were positive in the double-disk synergy test. By isoelectric focusing analysis, all of the isolates were found to produce a band of beta-lactamase activity with a pI of 5.9. Three of these isolates produced an additional band with a pI of 7.6. PCR and DNA sequencing identified these beta-lactamases as TEM-4 and SHV-2a, respectively. The remaining isolate, highly resistant to ceftazidime but susceptible to cefepime, produced a beta-lactamase that focused at pI 7.8. No synergy was detected by the double-disk synergy test. Sequence analysis of the bla gene amplified by PCR showed that the plasmid-mediated AmpC-type enzyme was ACC-1a. Fingerprinting analysis by repetitive-element PCR and enterobacterial repeat intergenic consensus-PCR suggested that 29 of the 31 Salmonella serotype Mbandaka isolates belonged to the same clonal population.

Lactococcin MMFII, a novel class IIa bacteriocin produced by Lactococcus lactis MMFII, isolated from a Tunisian dairy product

A novel bacteriocin, lactococcin MMFII, produced by Lactococcus lactis MMFII isolated from a Tunisian dairy product had been identified. The bacteriocin was purified to homogeneity from fresh overnight M17 broth culture by sulfate ammonium precipitation, cation-exchange chromatography, sep-pack chromatography and two steps of reverse-phase chromatography. The purified bacteriocin was heat stable, pH resistant and protease sensitive. Its amino acid sequence, obtained by Edman degradation, revealed a 37-amino acid peptide with two cysteine residues in positions 9 and 14 and a calculated mass of 4144.6 Da. Laser desorption mass spectrometry analysis gave a molecular mass of 4142.6, suggesting the presence of a disulfide bond within the purified bacteriocin. Lactococcin MMFII contains the N-terminal YGNGV consensus motif and is active against Listeria. Thus, it belongs to the class IIa bacteriocins figuring the first example of such a bacteriocin produced by a lactococcal strain.

Chemical synthesis, molecular modeling, and antimicrobial activity of a novel bacteriocin, MMFII

A new antimicrobial peptide, referred to as MMFII, was purified to homogeneity from lactic acid bacteria Lactococcus lactis, which were isolated from Tunisian dairy product. The complete amino acid sequence of the peptide has been established by amino acid analysis, Edman sequencing, and mass spectrometry and verified by solid-phase chemical synthesis. MMFII is a single-chain 37-residue polypeptide containing a single intramolecular disulfide bond, i.e., TSYGNGVHCNKSKCWIDVSELETYKAGTVSNPKDILW. It shares ca. 35% sequence identity with Leucocin A, a class IIa bacteriocin. Modeling based on the 3-D of Leucocin A shows three beta strands located in the N-terminal region (Thr1-Tyr3, Val7-Asn10, Lys13-Ile16) and an alpha helical domain from Asp17 to Asn31. When plotted as an alpha-helical wheel, the central alpha-helix of MMFII does not exhibit an amphipathic helical structure. The synthetic MMFII (sMMFII), obtained by the solid-phase method, was shown to be indistinguishable from the natural peptide. sMMFII is active against Lactococcus cremoris and Listeria ivanovii bacteria, whereas no activity was detected for any of the synthetic N-terminal truncated MMFII analogs Cys9-Trp37, Trp15-Trp37, and Val18-Trp37.

Treatment of liver metastases with moderate peritoneal carcinomatosis by hepatectomy and cytoreductive surgery followed by immediate post-operative intraperitoneal chemotherapy: feasibility and preliminary results

BACKGROUND/AIMS

Peritoneal carcinomatosis (PC) discovered during hepatectomy is usually a contraindication to resection. A potentially efficient treatment of PC is the resection of the macroscopic disease and the treatment of the residual microscopic disease with immediate post-operative intraperitoneal chemotherapy (IPIC) (before the entrapment of cancer cells inside the fibrin deposit which rapidly cover the injured tissues). Feasibility and survival results of this treatment, combined with major hepatectomy, have never been evaluated. The purpose of this study is to report tolerance and preliminary results in patients with liver metastases synchronous to moderate PC, treated with hepatectomy, complete cytoreductive surgery, and IPIC.

METHODOLOGY

Twelve patients with liver metastases and moderate PC from miscellaneous origins, underwent: 1) hepatectomy (9 of them were major hepatectomies); 2) complete cytoreductive surgery of the PC resecting between 20 and 150 nodules; and, 3) IPIC, for 5 days, according to histology.

RESULTS

There was no mortality. Morbidity was mainly due to four transient biliary leakages (33%) and there was no systemic complication due to the chemotherapy. After a median follow-up of 14.4 months, there was no detectable recurrence of the PC. Preliminary results concerning survival are promising with 7 patients without recurrent disease.

CONCLUSIONS

When a minimal or moderate PC is discovered during laparotomy for liver resection of metastases, the combination of hepatectomy with complete cytoreductive surgery of the peritoneal disease, followed with IPIC is logical and feasible. This aggressive treatment is well tolerated although the frequency of biliary leakage seems to be higher than that after standard hepatectomy. No recurrence of the peritoneal disease was detected and survival results are very promising.

[Esophagectomy for epidermoid cancer discovered during evaluation of ENT cancer]

The treatment of synchronous esophageal and head and neck carcinomas is difficult.

MATERIAL AND METHOD

Retrospective study of 33 patients treated with esophagectomy for an intrathoracic squamous cells carcinoma discovered during pan-endoscopy for a synchronous head and neck cancer.

RESULTS

In 7 cases (21%) it was advanced (pT3-4) esophageal cancers. The hospital mortality was 9%. Five year survival was 18% without stabilization of the survival curve, 60% of patients died of recurrence of tumor.

CONCLUSION

Esophagectomy is suitable for usT1-2 tumors if surgery is also indicated for the head and neck tumor. Radiochemotherapy is indicated for advanced usT3-4 esophageal tumors or when the treatment of the head and neck tumor is not surgery.