The non-vesicle cell-free DNA (cfDNA) induces cell transformation associated with horizontal DNA transfer

BACKGROUND

Cell-free DNA (cfDNA) is a source for liquid biopsy used for cancer diagnosis, therapy selection, and disease monitoring due to its non-invasive nature and ease of extraction. However, cfDNA also participates in cancer development and progression by horizontal transfer. In humans, cfDNA circulates complexed with extracellular vesicles (EV) and macromolecular complexes such as nucleosomes, lipids, and serum proteins. The present study aimed to demonstrate whether cfDNA not associated with EV induces cell transformation and tumorigenesis.

METHODS

Supernatant of the SW480 human colon cancer cell line was processed by ultracentrifugation to obtain a soluble fraction (SF) and a fraction associated with EV (EVF). Primary murine embryonic fibroblast cells (NIH3T3) underwent passive transfection with these fractions, and cell proliferation, cell cycle, apoptosis, cell transformation, and tumorigenic assays were performed. Next, cfDNA was analyzed by electronic microscopy, and horizontal transfer was assessed by human mutant KRAS in recipient cells via PCR and recipient cell internalization via fluorescence microscopy.

RESULTS

The results showed that the SF but not the EVF of cfDNA induced proliferative and antiapoptotic effects, cell transformation, and tumorigenesis in nude mice, which were reduced by digestion with DNAse I and proteinase K. These effects were associated with horizontal DNA transfer and cfDNA internalization into recipient cells.

CONCLUSIONS

The results suggest pro-tumorigenic effects of cfDNA in the SF that can be offset by enzyme treatment. Further exploration of the horizontal tumor progression phenomenon mediated by cfDNA is needed to determine whether its manipulation may play a role in cancer therapy.

Ultrasound, histopathological, and genetic features of uveal melanoma in a Mexican-Mestizo population

OBJECTIVE

To describe the ultrasound, histopathological and genetic characteristics of uveal melanoma in a Mexican-Mestizo population.

MATERIAL AND METHODS

A total of 39 enucleated eyes with a histopathological diagnosis of uveal melanoma were assessed by describing the clinical findings, and ultrasound, histopathological and genetic features.

RESULTS

A high correlation was observed between tumour height measurement using ultrasound and histopathology. In our cases, tumour size and reflectivity were higher compared with those reported in the literature. The preliminary data on the molecular assessment of the tumours show the presence of an unreported polymorphism (T>C IVS5+34) and one sample with GNAQ mutation (A>C CAA>CCA Gln 209 Pro).

CONCLUSION

Ultrasound is a reliable method to identify the size of the tumour. Furthermore, knowledge of the molecular mechanisms promises new perspectives for the development of new targeted therapeutics. Fortunately this leads to progress in the treatment of patients with metastatic disease or prevents it in those at high risk.

Upregulation of NKG2D ligands and enhanced natural killer cell cytotoxicity by hydralazine and valproate

Natural killer cells play a role in the immune antitumor response by recognizing and eliminating tumor cells through the engagement of NKG2D receptors with their ligands on target cells. This work aimed to investigate whether epigenetic drugs are able to increase MICA and MICB expression as well as NK cell cytotoxicity. Prostate, colon, breast and cervical cancer cell lines were analyzed for the expression of MICA and MICB at the mRNA and protein levels by RT-PCR, Western blot, flow cytometry and ELISA. The activating mark H3K4m2 at the MICA and MICB promoters was investigated by ChIP assays. Cytotoxicity of NK cells against the target epithelial cancer cells was investigated with the CD107 cytotoxicity assay. The results show that hydralazine and valproic acid not only increase the expression of MICA and MICB ligands of target cells, but also reduce their shedding to the supernatant. This upregulation occurs at the transcriptional level as revealed by increase of the H3K4 activating mark at the promoter of MICA and MICB genes. These effects are paralleled by increased cytotoxicity of NK cells, which was attenuated at different degrees by using blocking antibodies against the NKG2D receptor and ligands. In conclusion, our results demonstrate the ability of hydralazine and valproate to increase the NK activity against epithelial cancer cell lines and suggest that these drugs could reduce the levels of soluble MICA and MICB helping in avoiding tumor-induced suppression of NK cytotoxicity against the tumor.

Epigenetic therapy and cisplatin chemoradiation in FIGO stage IIIB cervical cancer

INTRODUCTION

This trial aimed to evaluate the safety and efficacy of epigenetic therapy associated with cisplatin chemoradiation in FIGO Stage IIIB patients.

METHODS

Hydralazine containing either 182 mg for rapid-, or 83 mg for slow acetylators and magnesium valproate were administered at 30 mg/kg tid. Both drugs were taken until intracavitary therapy was finished. Pelvic external beam radiation and low-dose rate brachytherapy were administered at a total cumulative dose to point A of at least 85 Gy. Weekly cisplatin at 40 mg/m2 was delivered for six cycles.

RESULTS

Twenty-two patients were included and 18 (82%) patients completed treatment. Mean dose to point A was 84.6 + 2.2. Median number of cisplatin cycles was 5.5 (range, 1-6). Brachytherapy was delayed for technical reasons; the mean overall treatment time was 11.8 weeks. Grade 3 anemia, leucopenia, neutropenia, and thrombocytopenia were observed in 9%, 45%, 45%, and 9% of patients, respectively.

CONCLUSIONS

Hydralazine and valproate are well-tolerated and safe when administered with cisplatin chemoradiation. Unfortunately, the suboptimal administration of brachytherapy for technical reasons in this study, precluded assessing the efficacy of epigenetic therapy. However, the tolerability of this regimen administered concurrent to radiation needs to be further tested.

Mutational analysis of BRCA1 and BRCA2 genes in Mexican breast cancer patients

Germline mutations in the BRCA1 and BRCA2 genes predispose to breast and ovarian cancer. A variable incidence of mutations has been reported for these genes. The contribution of BRCA1 and BRCA2 mutations to Mexican women with breast and/or ovarian cancer is not known. Because of the increasing prevalence of breast cancer in this population, it is necessary to study the presence of mutations in both genes. We screened BRCA1 and BRCA2 genes in 40 patients: 29 patients with a history of breast and/or ovarian cancer, and 11 patients with early-onset breast cancer (< 40 years), through denaturing high performance liquid chromatography analyses. We found two frameshift mutations in BRCA1 and one missense mutation in each gene. Additionally we found several intronic variants as well as synonymous mutations. We found 5% of deleterious mutations in the BRCA genes. Larger studies are needed to establish the significance and prevalence of BRCA mutations among Mexican women.

A phase II study of epigenetic therapy with hydralazine and magnesium valproate to overcome chemotherapy resistance in refractory solid tumors

BACKGROUND

Epigenetic aberrations lead to chemotherapy resistance; hence, their reversal by inhibitors of DNA methylation and histone deacetylases may overcome it.

PATIENTS AND METHODS

Phase II, single-arm study of hydralazine and magnesium valproate added to the same schedule of chemotherapy on which patients were progressing. Schedules comprised cisplatin, carboplatin, paclitaxel, vinorelbine, gemcitabine, pemetrexed, topotecan, doxorubicin, cyclophosphamide, and anastrozole. Patients received hydralazine at 182 mg for rapid, or 83 mg for slow, acetylators, and magnesium valproate at 40 mg/kg, beginning a week before chemotherapy. Response, toxicity, DNA methylation, histone deacetylase activity, plasma valproic acid, and hydralazine levels were evaluated.

RESULTS

Seventeen patients were evaluable for toxicity and 15 for response. Primary sites included cervix (3), breast (3), lung (1), testis (1), and ovarian (7) carcinomas. A clinical benefit was observed in 12 (80%) patients: four PR, and eight SD. The most significant toxicity was hematologic. Reduction in global DNA methylation, histone deacetylase activity, and promoter demethylation were observed.

CONCLUSIONS

The clinical benefit noted with the epigenetic agents hydralazine and valproate in this selected patient population progressing to chemotherapy' and re-challenged with the same chemotherapy schedule after initiating hydralazine and valproate' lends support to the epigenetic-driven tumor-cell chemoresistance hypothesis (ClinicalTrials.gov Identifier: NCT00404508).

A phase II trial of epigenetic therapy with hydralazine and magnesium valproate associated to doxorubicin and cyclophosphamide for locally advanced breast cancer

13147

Background: DNA methylation and histone deacetylation are the most studied epigenetic alterations in cancer. Hydralazine and magnesium valproate are proven DNA methylation and histone deacetylase inhibitors respectively that in combination exert antitumor effects by their own and potentate the effect of chemotherapy. Methods: Open label two-stage design phase II trial to evaluate safety and efficacy of hydralazine and magnesium valproate plus chemotherapy in terms of pathologic complete response as neoadjuvant treatment. A total of 42 patients will be accrued. Untreated patients with histological confirmation of breast cancer in clinical stage IIb-IIIa, and hematological, renal and hepatic normal function are elegible. Patients with any collagen disease and any cardiovascular condition were excluded. Treatment consisted on four 21-day courses of doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2 plus epigenetic therapy starting 7 days before the first cycle of chemotherapy and continued until the end of chemotherapy. Oral hydralazine dosed according to acetylator phenotype and magnesium valproate at 30mg/Kg. After chemotherapy patients were evaluated with mammography and then submitted to surgical resection. Results: 17 patients in the first-stage have been accrued. Their characteristics are as follows: Median age 45-y (39–67), 67% were stage IIIa, median size of tumor was 5 cm (3–10 cm). All patients had clinically positive axillary nodes, with median size of 2 cm (1–5 cm), 80% were ductal carcinomas and 80% had either intermediate or high grade; 77% were ER-positive and 30% over-expressed HER2. Hematological toxicity was the most common side effect, neutropenia grade 3/4 was found in 35% of cases, anemia grade 3/4 was present in 15% of cases and most presented transient grade 2 depressed level of consciousness. Seven patients have completed planned treatment, clinical responses were CR 2, PR 4 and SD 1; in 1 of 7 a pathological complete response was seen. Conclusions: Epigenetic therapy with hydralazine and magnesium valproate associated to conventional chemotherapy is well tolerated. Its antitumor efficacy is pending to evaluate.

No significant financial relationships to disclose.

Polymorphisms of the thiopurine S-methyl transferase gene (TMPT) in a Mexican population

20049

Background: Polymorphisms at the thiopurine S-methyltransferase coding gene (TPMT) determine enzyme activity and as a consequence the development of toxicity of thiopurine drugs. Methods: To test the frequency of polymorphisms of TPMT gene in Mexican population. 36 DNA samples from volunteer donors were analyzed. Genomic DNA from peripheral leukocytes was isolated by standard methods. Known (wild type and polymorphic) sequenced PCR fragments of the TPMT gene were used used as controls. PCR amplification: Fragments of the TPMT gene were amplified using the following oligonucleotides primers: Exon 5: 5′-CTGCATGTTCTTTGAAACCCTATGAA-3′ and 5′-CTTGAGGACAGAGAGGCTTTGACCTC-3′; exon 7: 5′-CTCCACACCCAGGTCC-ACACATT-3′ and 5′-GTATAGTACTAAAAAATTAAGACAGCTAAAC-3′; exon 10: 5′-AATCCTGATGTCATTCTTCATAGTATTT-3′ and 5′-CATCCATTACATTTTCAGG-CTTTAGCATAAT-3′. PCR products were then analyzed by denaturating high performance liquid chromatography (DHPLC) for the most frequent mutant TPMT alleles, according to the method developed by Schaeffeler et al (Clin Chem 2001; 47: 548) on an analysis system from Transgenomics Results: A high frequency of gene polymorphisms was identified, particularly in the exon 7 (14/36 = 38%), followed by exon 10 (3/36 = 8.3%) and 5 (2/36 = 5.5%). After analysing the three exons, the presence of mutations discriminating for TPMT alleles showed that 7/36 (19.4 %) were silent and located at T474C, in exon 7 (*1S) and 7/36 (19.4 %) were functional, and located in TPMT alleles *2 (2/36 = 5.5%), *3B (2/36 = 5.5%), *4 (2/36 = 5.5%) and *3B/4 (1/36= 2.7%). Conclusions: This is the first analysis of the polymorphisms at this gene in a Mexican population. The frequency of known silent polymorphisms was higher than those reported in other world regions but the frequency of functional polymorphism is within the range found in other reports. DHPLC is a highly sensitive, rapid and efficient method to identify relevant TPMT gene mutations which allows the screening for genetic variability in the TPMT gene . This trial was supported by a grant of CONACYT.

No significant financial relationships to disclose.

Neuroendocrine marker expression in cervical carcinomas of non-small cell type

Small-cell carcinomas of the uterine cervix are highly aggressive tumors. Up to 100% of these tumors express at least one neuroendocrine marker such as neuron-specific enolase (NSE), chromogranin A (CgA), and synaptophysin (SYN). In other tumor types such as non-small-cell carcinomas of the lung, colon, and prostate, the presence of these markers has been associated with a better prognosis in some studies, a worsened prognosis in others, or has had no prognostic effect in still other studies. However, little is known about their expression and prognostic significance in the common "non-small-cell" carcinomas of the uterine cervix. The primary tumors of 54 previously untreated patients with histologically confirmed non-small-cell carcinoma of the cervix uteri (squamous carcinoma, adenosquamous carcinoma, and adenocarcinoma) were analyzed by immunohistochemistry for expression of NSE, CgA, and SYN. The expression status was correlated to pathological characteristics and outcome. In addition, the expression of these markers was investigated in cervical carcinoma cell lines. None of the 54 tumors expressed NSE or CgA, although SYN was positive in five tumors (9%) of which four were squamous and one was adenocarcinoma. These five patients relapsed within the first 6 months of follow-up and four have died. Among eight cancer cell lines only one was positive for CgA and another one for SYN. We conclude that the neuroendocrine marker SYN is expressed in a small subset of non-small-cell carcinomas of the cervix and its expression seems to correlate with a poor outcome.

Membrane proteins in neoplasic and normal uterine cervix

Tumor cells exhibit phenotypic and genotypic differences in comparison to normal cells. These differences can be used to identify proteins important for tumor growth and, therefore, potentially used in the diagnosis and follow-up of patients. The objective of this work was to investigate the electrophoretic pattern of cytoplasm membrane proteins from normal and malignant cervix using polyacrylamide-SDS gels. A highly reproducible protein pattern was found in the 29 samples of normal cervix whereas three well-defined patterns of protein bands were observed in the 48 tumor specimens (pattern I: 25%, pattern II: 29.2% and pattern III: 45.8%). A low concentration or absence of high molecular weight proteins was observed (p<0.5) in tumor samples. None of the tumor protein patterns correlated with the clinicopathologic characteristics of patients. Nine out of 11 patients (82%) showing the pattern III had a complete clinical response whereas only 55% (11 out of 20) of those with patterns I and II showed a complete response. However, this difference was non-significant (p=0.1247). In conclusion, we demonstrate that there is a gain and loss of cytoplasmic membrane proteins in tumors, shown as different protein band patterns. These findings could have clinical and biological significance that must be further evaluated.

[Molecular bases of papillomavirus and polyomavirus carcinogenesis]

Polyomavirus is able to induce tumors in its natural host as well as to transform cells in cultures. On the other hand, human papillomavirus has been involved in several types of neoplasias such as anogenital lesions. Little is known about the mechanisms through which these viruses induce both transformation and tumorigenesis. The present, work shows some characteristics of the mechanisms that papillomavirus and polyomavirus use to participate in tumorigenesis. It has also been noticed that the infection caused by polyomavirus resembles that performed by papillomaviruses (which belong to the same Papovaviridae family). Some similarities and differences between these viruses are considered.