Safety and immunogenicity of a recombinant protein RBD fusion heterodimer vaccine against SARS-CoV-2.

In response to COVID-19 pandemic, we have launched a vaccine development program against SARS-CoV-2. Here we report the safety, tolerability, and immunogenicity of a recombinant protein RBD fusion heterodimeric vaccine against SARS-CoV-2 (PHH-1V) evaluated in a phase 1-2a dose-escalation, randomized clinical trial conducted in Catalonia, Spain. 30 young healthy adults were enrolled and received two intramuscular doses, 21 days apart of PHH-1V vaccine formulations [10 µg (n = 5), 20 µg (n = 10), 40 µg (n = 10)] or control [BNT162b2 (n = 5)]. Each PHH-1V group had one safety sentinel and the remaining participants were randomly assigned. The primary endpoint was solicited events within 7 days and unsolicited events within 28 days after each vaccination. Secondary endpoints were humoral and cellular immunogenicity against the variants of concern (VOCs) alpha, beta, delta and gamma. All formulations were safe and well tolerated, with tenderness and pain at the site of injection being the most frequently reported solicited events. Throughout the study, all participants reported having at least one mild to moderate unsolicited event. Two unrelated severe adverse events (AE) were reported and fully resolved. No AE of special interest was reported. Fourteen days after the second vaccine dose, all participants had a >4-fold change in total binding antibodies from baseline. PHH-1V induced robust humoral responses with neutralizing activities against all VOCs assessed (geometric mean fold rise at 35 days p < 0.0001). The specific T-cell response assessed by ELISpot was moderate. This initial evaluation has contributed significantly to the further development of PHH-1V, which is now included in the European vaccine portfolio.ClinicalTrials.gov Identifier NCT05007509EudraCT No. 2021-001411-82.

Orthoxenografts of Testicular Germ Cell Tumors Demonstrate Genomic Changes Associated with Cisplatin Resistance and Identify PDMP as a Resensitizing Agent.

Purpose: To investigate the genetic basis of cisplatin resistance as efficacy of cisplatin-based chemotherapy in the treatment of distinct malignancies is often hampered by intrinsic or acquired drug resistance of tumor cells.Experimental Design: We produced 14 orthoxenograft transplanting human nonseminomatous testicular germ cell tumors (TGCT) in mice, keeping the primary tumor features in terms of genotype, phenotype, and sensitivity to cisplatin. Chromosomal and genetic alterations were evaluated in matched cisplatin-sensitive and their counterpart orthoxenografts that developed resistance to cisplatin in nude mice.Results: Comparative genomic hybridization analyses of four matched orthoxenografts identified recurrent chromosomal rearrangements across cisplatin-resistant tumors in three of them, showing gains at 9q32-q33.1 region. We found a clinical correlation between the presence of 9q32-q33.1 gains in cisplatin-refractory patients and poorer overall survival (OS) in metastatic germ cell tumors. We studied the expression profile of the 60 genes located at that genomic region. POLE3 and AKNA were the only two genes deregulated in resistant tumors harboring the 9q32-q33.1 gain. Moreover, other four genes (GCS, ZNF883, CTR1, and FLJ31713) were deregulated in all five resistant tumors independently of the 9q32-q33.1 amplification. RT-PCRs in tumors and functional analyses in Caenorhabditis elegans (C. elegans) indicate that the influence of 9q32-q33.1 genes in cisplatin resistance can be driven by either up- or downregulation. We focused on glucosylceramide synthase (GCS) to demonstrate that the GCS inhibitor DL-threo-PDMP resensitizes cisplatin-resistant germline-derived orthoxenografts to cisplatin.Conclusions: Orthoxenografts can be used preclinically not only to test the efficiency of drugs but also to identify prognosis markers and gene alterations acting as drivers of the acquired cisplatin resistance. Clin Cancer Res; 24(15); 3755-66. ©2018 AACR.

Geriatric Assessment Predicts Survival and Competing Mortality in Elderly Patients with Early Colorectal Cancer: Can It Help in Adjuvant Therapy Decision-Making?

BACKGROUND: The challenge when selecting elderly patients with colorectal cancer (CRC) for adjuvant therapy is to estimate the likelihood that death from other causes will preclude cancer events from occurring. The aim of this paper is to evaluate whether comprehensive geriatric assessment (CGA) can predict survival and cancer-specific mortality in elderly CRC patients candidates for adjuvant therapy. MATERIAL AND METHODS: One hundred ninety-five consecutive patients aged ≥75 with high-risk stage II and stage III CRC were prospectively included from May 2008 to May 2015. All patients underwent CGA, which evaluated comorbidity, polypharmacy, functional status, geriatric syndromes, mood, cognition, and social support. According to CGA results, patients were classified into three groups-fit, medium-fit, and unfit-to receive standard therapy, adjusted treatment, and best supportive care, respectively. We recorded survival and cause of death and used the Fine-Gray regression model to analyze competing causes of death. RESULTS: Following CGA, 85 (43%) participants were classified as fit, 57 (29%) as medium-fit, and 53 (28%) as unfit. The univariate 5-year survival rates were 74%, 52%, and 27%. Sixty-one (31%) patients died due to cancer progression (53%), non-cancer-related cause (46%), and unknown reasons (1%); there were no toxicity-related deaths. Fit and medium-fit participants were more likely to die due to cancer progression, whereas patients classified as unfit were at significantly greater risk of non-cancer-related death. CONCLUSION: CGA showed efficacy in predicting survival and discriminating between causes of death in elderly patients with high-risk stage II and stage III resected CRC, with potential implications for shaping the decision-making process for adjuvant therapies. IMPLICATIONS FOR PRACTICE: Adjuvant therapy in elderly patients with colorectal cancer is controversial due to the high risk for competing events among these patients. In order to effectively select older patients for adjuvant therapy, we have to weigh the risk of cancer-related mortality and the potential survival benefits with treatment against the patient's life expectancy, irrespective of cancer. This prospective study focused on the prognostic value of geriatric assessment for survival using a competing-risk analysis approach, providing an important contribution on the treatment decision-making process and helping clinicians to identify elderly patients who might benefit from adjuvant chemotherapy among those who will not.

Nanofluidic Digital PCR and Extended Genotyping of RAS and BRAF for Improved Selection of Metastatic Colorectal Cancer Patients for Anti-EGFR Therapies.

The clinical significance of low-frequent RAS pathway-mutated alleles and the optimal sensitivity cutoff value in the prediction of response to anti-EGFR therapy in metastatic colorectal cancer (mCRC) patients remains controversial. We aimed to evaluate the added value of genotyping an extended RAS panel using a robust nanofluidic digital PCR (dPCR) approach. A panel of 34 hotspots, including RAS (KRAS and NRAS exons 2/3/4) and BRAF (V600E), was analyzed in tumor FFPE samples from 102 mCRC patients treated with anti-EGFR therapy. dPCR was compared with conventional quantitative PCR (qPCR). Response rates, progression-free survival (PFS), and overall survival (OS) were correlated to the mutational status and the mutated allele fraction. Tumor response evaluations were not available in 9 patients and were excluded for response rate analysis. Twenty-two percent of patients were positive for one mutation with qPCR (mutated alleles ranged from 2.1% to 66.6%). Analysis by dPCR increased the number of positive patients to 47%. Mutated alleles for patients only detected by dPCR ranged from 0.04% to 10.8%. An inverse correlation between the fraction of mutated alleles and radiologic response was observed. ROC analysis showed that a fraction of 1% or higher of any mutated alleles offered the best predictive value for all combinations of RAS and BRAF analysis. In addition, this threshold also optimized prediction both PFS and OS. We conclude that mutation testing using an extended gene panel, including RAS and BRAF with a threshold of 1% improved prediction of response to anti-EGFR therapy. Mol Cancer Ther; 15(5); 1106-12. ©2016 AACR.

Comprehensive molecular characterisation of hereditary non-polyposis colorectal tumours with mismatch repair proficiency.

BACKGROUND: Hereditary non-polyposis colorectal cancer (CRC) without mismatch repair (MMR) defects occurs in almost half of high-risk CRC families, but its genetic cause(s) is(are) still unknown. We aimed to identify unique molecular features that differentiate hereditary from sporadic MMR-proficient colorectal tumours. METHODS: Genomic alterations in 16 tumours from 14 Amsterdam I-II families were studied using the genome-wide copy number OncoScan™ FFPE microarray. Somatic mutation hotspots in BRAF, KRAS, PIK3CA and TP53 were analysed in 37 colorectal tumours from 26 families and in 99 sporadic MMR-proficient CRCs, using direct automated sequencing and KASPar genotyping assays. CpG methylation index was studied in 25 tumours from 19 families by methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA). RESULTS: Our findings indicate that hereditary MMR-proficient tumours have overlapping genomic profiles to those obtained in sporadic cases, both suggestive of high chromosomal instability, and no high CpG methylation index. Nevertheless, we identified a significant increase in the frequency of chromosome 2p and 2q gains, and of 10 q loss in Amsterdam I families, as well as low frequency of >2 Mb copy-neutral or -gained loss of heterozygosity (LOH). No statistically significant differences in the frequency of BRAF, KRAS, PIK3CA and TP53 mutations or in the gene mutation patterns were observed. However, TP53 mutations appeared almost twice more frequently in sporadic tumours. CONCLUSIONS: Overall, hereditary MMR-proficient CRCs display similar molecular characteristics than their sporadic counterparts. However, the differences identified, such as the chromosome 2 gain, 10 q loss, or the under-representation of TP53 mutations, if validated in larger series, might be of relevance in the clinical setting and/or in the identification of germline defects underlying some of these familial cases.

Stromal interaction molecule 2 (STIM2) is frequently overexpressed in colorectal tumors and confers a tumor cell growth suppressor phenotype.

Allelic imbalances at chromosome 4p have been largely documented in many different tumor types. In colorectal cancer, loss of heterozygosity (LOH) at 4p15 has been associated with tumor aggressiveness and poor patient outcome, however no target genes in the region have been identified to date. Since stromal interaction molecule 2 (STIM2) is located at 4p15.2 and has been proposed as a candidate gene for this region in glioblastoma multiforme, we aimed at investigating the role of STIM2 in colorectal cancer. We studied STIM2 transcript expression levels in a collection of xenografted primary colorectal tumors (n = 20) and a well-annotated tumor series of colorectal cancer (n = 140). We observed an overexpression of STIM2 in 63.5% of the cases that was associated with a less invasive phenotype. In vitro and in vivo functional studies with colon cancer cell lines revealed that overexpression of STIM2 reduced cell proliferation and tumor growth, respectively. Our work presents several lines of evidence indicating that STIM2 overexpression is a frequent trait in colorectal cancer that results in cell growth suppression, certifying that even in the absence of somatic genetic or epigenetic alterations, recurrent regions of LOH should still be considered a hallmark for the presence of relevant genes for tumorigenesis.

Fetal liver-derived mesenchymal stem cell engraftment after allogeneic in utero transplantation into rabbits.

Prenatal transplantation of genetically engineered mesenchymal stem cells (MSCs) might benefit prevention or treatment of early-onset genetic disorders due to the cells' intrinsic regenerative potential plus the acquired advantage from therapeutic transgene expression. However, a thorough assessment of the safety, accessibility, and behavior of these MSCs in the fetal environment using appropriate animal models is required before we can advance toward a clinical application. We have recently shown that fetal rabbit liver MSCs (fl-MSCs) have superior growth rate, clonogenic capability, and in vitro adherence and differentiation abilities compared with adult rabbit bone marrow MSCs. In this follow-up study, we report safe and widespread distribution of recombinant pSF-EGFP retrovirus-transduced fl-MSCs (EGFP(+)-fl-MSCs) in neonatal rabbit tissues at 10 days after fetal allogeneic transplantation through both intrahepatic and intra-amniotic administration. Conversely, a more restricted biodistribution pattern according to the route of administration was apparent in the young rabbits intervened at 16 weeks after fetal EGFP(+)-fl-MSC transplantation. Furthermore, the presence of these cells in the recipients' tissues, tracked with the reporter provirus, was inversely related to the developmental stage of the fetuses at the time of intervention. Long-term engraftment was confirmed both by fluorescence in situ hybridization analysis on touch tissue imprints using a chromosome Y-specific BAC probe, and by immunohistochemical localization of EGFP expression. Finally, there was no evidence of immune responses against the transplanted EGFP(+)-fl-MSCs or the EGFP transgenic product in the treated young rabbits. Thus, cell transplantation approaches using genetically engineered fetal MSCs may prove particularly valuable to frontier medical treatments for congenital birth defects in perinatology.

The ß-interferon scaffold attachment region confers high-level transgene expression and avoids extinction by epigenetic modifications of integrated provirus in adipose tissue-derived human mesenchymal stem cells.

Because of their abundance and ease of isolation, multilineage differentiation, and paracrine and immunoregulatory capabilities, genetically engineered adipose tissue-derived mesenchymal stem cells (ASCs) might combine cell- and gene therapy-based strategies for efficacious tissue repair/regeneration. In this report, we aimed to analyze and influence the long-term dynamics of transgene expression in ASCs transduced with different gammaretroviral vector configurations incorporating the human ß-interferon scaffold attachment region (IFN-SAR) and/or chicken 5'HS4 ß-globin insulator sequences. In our undifferentiated ASC culture model, naked retroviral vectors experienced EGFP transgene extinction correlating with increases in both H3 histone deacetylation and CpG dinucleotide methylation within the 5' long terminal repeat-primer-binding site proviral region. Retroviral configurations incorporating the referred boundary elements alone or combined were able to prevent the development of the above epigenetic events and to reduce transgene extinction to different degrees. Particularly, the IFN-SAR sustained the highest levels of H3 histone acetylation and transgene expression throughout the study. Analogously, ASCs differentiating to adipocytes or osteocytes experienced a gradual decline of EGFP expression using naked retroviral vectors. In contrast, only retroviral configurations including the IFN-SAR alone were able to overcome the epigenetic pressure, yielding high-level, uniform transgene expression throughout both lineage differentiation processes. Thus, embedding the IFN-SAR in retroviral vectors should have positive implications in gene repair strategies using ASCs.

Identification and comprehensive characterization of large genomic rearrangements in the BRCA1 and BRCA2 genes.

Large genomic rearrangements are estimated to account for approximately 5-10% of all disease-causing mutations in BRCA1 and BRCA2 genes in patients with hereditary breast and ovarian cancer syndrome (HBOC). We use MRC-Holland Multiplex Ligation-dependent Probe Amplification (MLPA) to screen for such rearrangements in patients with HBOC and as a first step in our genetic testing workflow. The technique was applied to a set of 310 independent patients and detected eight different copy number alterations, corresponding to 2.6% of the studied samples. MLPA was also found to identify point mutations located in probe sequences. As commercial MLPA tests are not suitable for determining the specific breakpoints or for defining the exact extent of rearrangements, we applied a set of different complementary techniques to characterize these genetic alterations with greater precision. Long-range PCR amplification, RNA analysis, SNP-array chips, non-commercial MLPA probes, and FISH analysis were used to fully define the extent and mechanism of each alteration. In BRCA1, six rearrangements were characterized: deletion of E22, duplication of E9-E24, deletion of E16-E23, deletion of E1-E13, deletion of E1-E2 and duplication of E1-E2. In BRCA2, we studied a deletion of E15-E16 and a deletion of E1-E24. To the best of our knowledge, this is the most comprehensive study of the nature and underlying molecular causes of these mutational events in the BRCA1/2 genes.

Comparative genomic hybridization analysis reveals new different subgroups in early-stage bladder tumors.

OBJECTIVES: To classify bladder tumors according to their genomic imbalances and evaluate their association with patient's outcome. METHODS: Sixty-three superficially and minimally invasive bladder tumors were analyzed by conventional comparative genomic hybridization. Subtelomeric screening in 15 of these tumors was performed by multiplex ligation-dependent probe amplification. RESULTS: Losses of 9q and 9p (32% and 25% of all cases, respectively) as well as gains of chromosomes Xq and Xp (28% and 25%, respectively) were the most frequent chromosome imbalances. Losses of 8p and gains in 1q and 8q were detected in >20% of cases. Tumors were classified into 3 groups according to their individualized pattern of gains and losses. The largest group was characterized by few chromosome imbalances, presenting 77% and 49% of the Ta and T1 tumors, respectively. Another group characterized by chromosomal gains, was composed of equal number of Ta and T1 tumors, with +1q and +17q gains being the most common imbalances. A minority group was characterized by chromosomal losses on 11q, 5q, and 6q. The multiplex ligation-dependent probe amplification study showed good correlation with comparative genomic hybridization results. With regard to the biological significance of this classification, a remarkable fact is that this minority group composed mainly of T1 tumors, showed a significant decrease in patient overall survival. CONCLUSIONS: Our data suggest that superficial carcinomas of the bladder can be subdivided into a larger number of subclasses than had previously been expected. Our results also demonstrate a decreased survival among patients whose tumors show more genomic losses than gains.

Tracking the origins of the bilaterian Hox patterning system: insights from the acoel flatworm Symsagittifera roscoffensis.

Genes of the Hox cluster encode for transcriptional regulators that show collinear expression along the anteroposterior (AP) body axis in all bilateral animals. However, it is still unclear when in the evolutionary history of bilaterians the Hox system first conferred positional identity along the AP-axis. Recent molecular phylogenies have convincingly shown that the acoel flatworms, traditionally classified within the Platyhelminthes, are the sister group of the remaining Bilateria, branching out before the common ancestor of protostomes, and deuterostomes (the so-called PDA). This key phylogenetic position offers the opportunity to search for the presence and early role of Hox cluster genes to pattern the AP axis in acoels. Here, we report on the cloning, genomic arrangement, and expression domains of Hox genes in Symsagittifera roscoffensis. Three Hox genes were detected: one from each of the major groups of Hox genes, which are anterior, central, and posterior. In bacterial artificial chromosome cloning, sequencing, and chromosomal fluorescence in situ hybridization, Hox genes were not observed as being clustered in a unique genomic region. Nevertheless, despite its dispersion within the genome, Hox genes are expressed in nested domains along the AP axis in the juvenile worm. The basic set of Hox genes in acoels and their coarse nested spatial deployment might be the first indicators of the role of Hox genes in the evolution of bilateral symmetry and AP positional identity from a hypothetical radial ancestor.

Detection of APC gene deletions using quantitative multiplex PCR of short fluorescent fragments.

BACKGROUND: approximately 20% of classic familial adenomatous polyposis (FAP) cases and 70% to 80% of attenuated FAP (AFAP) cases are negative for the APC/MUTYH point mutation. Quantitative multiplex PCR of short fluorescent fragments (QMPSF), a technique for detecting copy number alterations, has been successfully applied to several cancer syndrome genes. We used QMPSF for the APC gene to screen FAP APC/MUTYH mutation-negative families to improve their diagnostic surveillance. METHODS: we set up and validated APC-gene QMPSF using 23 negative and 1 positive control and examined 45 (13 FAP and 32 AFAP) unrelated members of APC/MUTYH mutation-negative families for copy number alterations. We confirmed the results using multiplex ligation-dependent probe amplification (MLPA). We used different approaches such as sequencing, quantitative real time-PCR (QRT-PCR), and fluorescence in situ hybridization (FISH) to further characterize the identified deletions. RESULTS: APC QMPSF was capable of detecting deletions with an acceptable variability, as shown by mean values (SD) of allele dosage for the deleted control obtained from intra- and interexperimental replicates [0.52 (0.05) and 0.45 (0.10)]. We detected 3 gross deletions in 13 (23%) of the classic FAP cases analyzed (1 complete gene deletion and 2 partial deletions encompassing exons 9 and 10 and exons 11-15, respectively). No rearrangements were detected in the 32 AFAP cases. CONCLUSIONS: QMPSF is able to detect rearrangements of the APC gene. Our findings highlight the importance of using a copy number alteration methodology as a first step in the routine genetic testing of FAP families in the clinical setting.

Altered expression of 12S/MT-RNR1, MT-CO2/COX2, and MT-ATP6 mitochondrial genes in prostate cancer.

BACKGROUND: Prostate cancer is one of the commonest cancers worldwide and is responsible for nearly 6% of all male cancer deaths. Despite this relevance, the mechanisms involved in the development and progression of this malignancy remain unknown. The involvement of polypeptides of the mitochondrial respiratory chain, the Krebs cycle and the glutathione antioxidant system in this type of cancer has been previously described, although no publication has focused on the expression of mitochondrial genes in the prostate of PCa patients. METHODS: We have determined by reverse transcription-quantitative PCR (RT-qPCR) the relative amount of the transcripts of eight mitochondrial genes (MT-ND2, MT-ND4, MT-ND6, MT-CYB, 12S/MT-RNR1, 16S/MT-RNR2, MT-CO2/COX2, MT-ATP6), and four nuclear genes (COX11, GSR, CS, ACO2), all of them key players in the normal metabolism of mitochondria. Additionally we analyzed the expression of Cyclophilin A (PPIA). RESULTS: We observed differential expression of mitochondrial 12S/MT-RNR1, MT-CO2/COX2, and MT-ATP6 transcripts in tumor samples when compared to their paired normal samples. CONCLUSIONS: The amount of mitochondrial 12S/MT-RNR1, MT-CO2/COX2, and MT-ATP6 transcripts is significantly decreased in tumor samples when compared to their paired normal sample, suggesting that mitochondrial gene expression is altered in PCa.

Aneuploidy of chromosome Y in prostate tumors and seminal vesicles: a possible sign of aging rather than an indicator of carcinogenesis?

Chromosome Y aneuploidies have been reported as one of the recurrent cytogenetic findings in prostate cancer (PCa) and many other solid and hematological tumors. We have studied this aneuploidy in 28 patients with PCa undergoing radical prostatectomy, one patient with benign hyperplasia (BPH) and four organ donors. A total of 72 samples have been studied: 17 tumors, 25 nontumor prostate tissues, 1 BPH, 21 seminal vesicles samples obtained along with the prostate when patients underwent radical prostatectomy and prostate tissues and seminal vesicles from four organ donors. We have also studied the aneuploidy of chromosome Y in peripheral blood from four of the patients and in seminal vesicles of 11 individuals with bladder cancer (BC). The study has been performed by Fluorescence in situ hybridization (FISH) in uncultured cells. Our results indicate that complete loss of chromosome Y is found in almost all the seminal vesicles both from patients with PCa and patients with BC (samples obtained from the tissue bank), and is more frequent in prostate tumors than in nontumor samples. The percentages of chromosome Y loss in the tissues analyzed are significatively higher than expected in lymphocytes considering the patient's age as reported in the literature. The high percentage of chromosome Y loss found in the nonmalignant seminal vesicles of these patients may be an indicator of an ageing process rather than a primary cytogenetic alteration in the carcinogenesis of the prostate. However, a contribution of this loss to chromosomal instability and therefore, to the multistep tumorigenic process, cannot be discarded.

Molecular characterization of a t(9;12)(p21;q13) balanced chromosome translocation in combination with integrative genomics analysis identifies C9orf14 as a candidate tumor-suppressor.

A large number of nevi (LNN) is a high risk phenotypic trait for developing cutaneous malignant melanoma (CMM). In this study, the breakpoints of a t(9;12)(p21;q13) balanced chromosome translocation were finely mapped in a family with LNN and CMM. Molecular characterization of the 9p21 breakpoint identified a novel gene C9orf14 expressed in melanocytes disrupted by the translocation. Integrative analysis of functional genomics data was applied to determine the role of C9orf14 in CMM development. An analysis of genome-wide DNA copy number alterations in melanoma tumors revealed the loss of the C9orf14 locus, located proximal to CDKN2A, in approximately one-fourth of tumors. Analysis of gene expression data in cancer cell lines and melanoma tumors suggests a loss of C9orf14 expression in melanoma tumorigenesis. Taken together, our results indicate that C9orf14 is a candidate tumor-suppressor for nevus development and late stage melanoma at 9p21, a region frequently deleted in different types of human cancers.

Identification of somatic and germline mitochondrial DNA sequence variants in prostate cancer patients.

Prostate cancer (PCa) is the second most frequent cancer among men in the European Union and the most common in the United States. Older age and a positive family history of PCa are important risk factors, but little is known about the disease aetiology. Mitochondria are involved in essential cellular pathways, some of which have been associated with tumorigenesis. We analysed the presence of sequence variants, depletion and rearrangements in the mitochondrial DNA (mtDNA) of PCa patients. Sequencing of the D-loop and genes RNR1 and 2, ND3, ND4L and ND4, and long-range and real-time PCR techniques were carried out on 51 samples (41 from patients and 10 from controls). Normal, hyperplastic or tumour samples were obtained from 17 patients. Six patients' seminal vesicles were also investigated as an additional patient's control tissue (these structures seldom develop tumours). Neither depletion nor mtDNA rearrangements were detected. In contrast, 94 mtDNA sequence variants were identified, 9 previously unreported. The regions presenting more sequence variants were MT-DLOOP (52%), MT-RNR2 (14%) and MT-ND4 (13%). The patients' seminal vesicles studied showed the same set of variants as the corresponding prostate, suggesting either that the pathogenic role of these particular variants is minor or that they participate in the prostatic carcinogenesis in combination with other factors absent in seminal vesicles. Five patients (29.4%) harboured eight somatic changes in the mtDNA. One affects a conserved residue and three have not been previously described. The analysis of other genes in the mtDNA molecule might demonstrate an even higher incidence of mtDNA somatic variants in these PCa patients.

Tissue imprints or primary cultures: which strategy to use to study cytogenetic clonality?

Touch preparations or imprints have been extensively used in cytogenetics to avoid primary cultures, especially when studying solid tumors which are hard to grow in vitro. Interphase nuclei studies by FISH have been validated in several sample types; however, to our knowledge, a comparison between both methods when studying clonality has not yet been published. We have performed a comparative FISH study between touch preparations and cultured cells to assess their reliability when studying the aneuploidy of chromosome Y in mosaicism. Our results in 23 samples indicate that aneuploidy of chromosome Y assessed in cells from tissue cultures versus cells obtained from touch preparations from seminal vesicles of patients with prostate cancer is not comparable. The percentage of aneuploid cells is higher in cultured cells. Attention, therefore, must be paid not to overestimating or underestimating the number of aneuploid cells detected when using interphase FISH studies, especially in solid tumors where clonality is very frequent. Also, according to our results, it is reasonable to extrapolate that when performing interphase nuclei studies in paraffin sections or tissue microarray, and therefore underestimations of aneuploidy could be reported. This might be of special relevance if the aneuploidy detected correlates with the tumor progression or might be used as a prognostic factor.

Suitability of oligonucleotide-mediated cystic fibrosis gene repair in airway epithelial cells.

BACKGROUND: Non-viral vector-mediated targeted gene repair could become a useful alternative to classical gene addition strategies. The methodology guarantees a physiologically regulated and persistent expression of the repaired gene, with reported gene conversion and phenotypic correction efficiencies approaching 40-50% in some in vitro and in vivo models of disease. This is particularly important for cystic fibrosis (CF) because of its complex pathophysiology and the cellular heterogeneity of the cystic fibrosis transmembrane conductance regulator (CFTR) gene expression and function in the lung. METHODS: A cell-free biochemical assay was applied to assess the ability of CF airway epithelial cells to support chimeraplast-mediated repair. In addition, a methodology allowing the relative quantification of the percentage of W1282X mutation repair in a heterozygous background using the PCR/oligonucleotide ligation assay (PCR/OLA) was developed. The performance of different chimeraplast and short single-stranded oligonucleotide structures delivered by non-viral vectors and electroporation was evaluated. RESULTS: Chimeraplast-mediated repair competency was corroborated in CF airway epithelial cells. However, their repair activity was about 5-fold lower than that found in liver cells. Moreover, regardless of the corrector oligonucleotide structure applied to our CF bronchial epithelial cells, of compound heterozygous genotype (F508del/W1282X), the percentage of their resulting wild-type allele in the W1282X (exon 20) locus of the CFTR gene was not significantly different from that of the control untreated cells by our PCR/OLA assay (confidence interval at 95% +/- 4 allele wild-type). CONCLUSIONS: Oligonucleotide-mediated CFTR gene repair is an inefficient process in CF airway epithelial cells. Further improvements in oligonucleotide structure, nuclear delivery and/or the capability for mismatch repair stimulation will be necessary to achieve therapeutic levels of mutation correction in these cells.