In Vitro and In Vivo Effects of the Combination of Polypurine Reverse Hoogsteen Hairpins against HER-2 and Trastuzumab in Breast Cancer Cells

Therapeutic oligonucleotides are powerful tools for the inhibition of potential targets involved in cancer. We describe the effect of two Polypurine Reverse Hoogsteen (PPRH) hairpins directed against the ERBB2 gene, which is overexpressed in positive HER-2 breast tumors. The inhibition of their target was analyzed by cell viability and at the mRNA and protein levels. The combination of these specific PPRHs with trastuzumab was also explored in breast cancer cell lines, both in vitro and in vivo. PPRHs designed against two intronic sequences of the ERBB2 gene decreased the viability of SKBR-3 and MDA-MB-453 breast cancer cells. The decrease in cell viability was associated with a reduction in ERBB2 mRNA and protein levels. In combination with trastuzumab, PPRHs showed a synergic effect in vitro and reduced tumor growth in vivo. These results represent the preclinical proof of concept of PPRHs as a therapeutic tool for breast cancer.

Trioleyl Pyridinium, a Cationic Transfection Agent for the Lipofection of Therapeutic Oligonucleotides into Mammalian Cells

BACKGROUND

One of the most significant limitations that therapeutic oligonucleotides present is the development of specific and efficient delivery vectors for the internalization of nucleic acids into cells. Therefore, there is a need for the development of new transfection agents that ensure a proper and efficient delivery into mammalian cells.

METHODS

We describe the synthesis of 1,3,5-tris[(4-oelyl-1-pyridinio)methyl]benzene tribromide (TROPY) and proceeded to the validation of its binding capacity toward oligonucleotides, the internalization of DNA into the cells, the effect on cell viability, apoptosis, and its capability to transfect plasmid DNA.

RESULTS

The synthesis and chemical characterization of TROPY, which can bind DNA and transfect oligonucleotides into mammalian cells through clathrin and caveolin-mediated endocytosis, are described. Using a PPRH against the antiapoptotic survivin gene as a model, we validated that the complex TROPY-PPRH decreased cell viability in human cancer cells, increased apoptosis, and reduced survivin mRNA and protein levels. TROPY was also able to stably transfect plasmid DNA, as demonstrated by the formation of viable colonies upon the transfection of a dhfr minigene into dhfr-negative cells and the subsequent metabolic selection.

CONCLUSIONS

TROPY is an efficient transfecting agent that allows the delivery of therapeutic oligonucleotides, such as PPRHs and plasmid DNA, inside mammalian cells.

Preirradiation ifosfamide, carboplatin, and etoposide for the treatment of anaplastic astrocytomas and glioblastoma multiforme: a phase II study

BACKGROUND

Central nervous system (CNS) tumors are the second most common pediatric tumors. Astrocytomas represent 35% of all CNS tumors in children. Traditional treatment of anaplastic astrocytoma (AA) and glioblastoma multiforme (GM) consisting of surgery-radiotherapy-chemotherapy with nitrosoureas has resulted in a survival rate of 26% at 1 year. Neoadjuvant chemotherapy has proven good results in the treatment of other solid tumors. Chemotherapy with ifosfamide, carboplatin, and etoposide (ICE) permits synergism among the different drugs and sensitizes the tumor to radiotherapy. Our objective was to evaluate the efficacy, security, and survival rate of postoperative chemotherapy with ICE in pediatric patients with AA or GM.

METHODS

Phase II study. We evaluated 11 children with AA or GM who had received no prior treatment. A magnetic resonance image (MRI) study of the tumor was made after surgery to evaluate residual tumor and routine laboratory analysis. Chemotherapy with carboplatin, ifosfamide and etoposide was given every 3 weeks for four courses. MRI studies were repeated after the second and last courses and laboratory analyses were carried out before each course to evaluate toxicity. Each patient then received hyperfractionated radiotherapy and a final MRI was done at the end of the treatment.

RESULTS

Sixty percent of the patients had partial response, 30% complete response after two courses, and 60% of CR after four courses. Supratentorial and infratentorial tumors had a good response to chemotherapy. Brainstem tumors had an initial response after two courses and then increased in size. AA was the tumor with the greatest reduction of residual tumor after treatment. Overall and free survival at 53 months was 70%. To date, three patients have died secondary to tumoral progression. There have been no relapses in the seven patients with a CR.

CONCLUSIONS

Postoperative chemotherapy with ICE reduces the tumor size and increases the survival rate of pediatric patients with malignant astrocytomas with minimal toxicity. Brainstem responded poorly to treatment.

Security and maximal tolerated doses of fluvastatin in pediatric cancer patients

BACKGROUND

The role of cholesterol in neoplasic cell growth and its inhibition by drugs has recently been studied. Cholesterol biosynthesis inhibitors have been used as adjuvants in the treatment of cancer and possibly as prophylactic in carcinogenesis.

OBJECTIVE

The objective of the study was to determine the maximal tolerated doses (MTD) and toxic effects of fluvastatin in pediatric cancer patients.

METHODS

This study was carried out in a third level Social Security Hospital in Mexico City. We included pediatric patients from April 1996 to May 1997. All were terminal cancer patients who did not respond to conventional therapies. Fluvastatin was given p.o. at doses of 2 mg/kg/day for 14 days every 4 weeks in three patients. Subsequent cohorts of three patients each had increments of 2 mg/kg/day of the drug until maximal tolerated doses were found. Toxic effects of the drug were evaluated by physical exploration, laboratory assays and a questionnaire given to each patient.

RESULTS

Twelve patients were included. Diagnoses included two osteosarcomas, eight central nervous system tumors, one lung tumor, and one Ewing's sarcoma. Ten patients died within 1 to 18 months. Two are alive 22 months after inclusion into the study, both with anaplasic astrocytoma. A total of 27 courses were administered. The MTD was 8 mg/kg/day. Toxic effects were insomnia, nausea, vomiting, abdominal distention and myalgias. Toxicity was dose-dependent. Laboratory assays demonstrated no significant changes during treatment.

CONCLUSIONS

Fluvastatin can be safely used at doses of 8 mg/kg/day in pediatric patients with cancer. This dose should be used in additional trials.

[Astrocytomas in pediatrics. The prognostic factors and survival]

Tumors of the central nervous system are the second most frequent malignancy in children under the age of 15 the majority of which are astrocytomas. The purpose of this paper is to analyze the effect of some factors on the survival of patients with astrocytomas. We reviewed the clinical charts of patients with a diagnosis of astrocytoma from 1984 to 1995 and we analyzed the age, sex, location, malignant grade and survival according to the actuarial method and log rank tests. A total of 39 patients were detected, 43% were supratentorial, 13% cerebellar and 43% from the brain stem. There was a better prognosis for those located supratentorial or cerebellar with respect to those in the brain stem, with statistical significance. The treatment consisted in surgical resection in 26 patients, 17 of which were found to have a high grade of malignancy and 9 with low grade, with statistically better prognosis for low grade tumors. There were 17 deaths during the period, with 8 of these patients having a high grade tumor a 10, with brain stem tumors. Forty-one percent of the patients that died did so in the first year and 94% during the first two years after diagnosis. Patients with cerebellar astrocytoma and patients with low-grade astrocytomas had the best prognosis.

[Lactic dehydrogenase as a prognostic factor in the development of pulmonary metastatic disease in patients with osteosarcoma]

Remarkable progress has been made in the treatment of osteosarcoma in the past two decades as a result of the development of effective adjuvant chemotherapy. However, the prognosis is poor in patients with early lung metastases. We review the lactate dehydrogenase release prognostic factor in the development of early lung metastases. This is a retrospective study. Eighteen patients with osteosarcoma were divided in two groups: Group A, patients with normal lactate dehydrogenase and Group B, patients with elevated lactate dehydrogenase. A univaried analysis was established. Ten patients (55%) had elevated levels of lactate dehydrogenase at diagnosis; nine of these patients developed lung metastases in the first twelve months. The difference in patients with normal levels of lactate dehydrogenase was significant (p: 0.02). The value of lactate dehydrogenase as an isolated single factor is limited. It is necessary to consider the tumoral volume, the patient's age and the histologic subtype in the prognosis of these patients, to predict the early development of pulmonary metastatic disease.

[Hodgkin's disease with the nephrotic syndrome. A case report]

It is presented a child with Hodgkin's disease which at diagnosis present associated at nephrotic syndrome. Male of nine years old which present a ganglionic growing of left jugular chain of one year evolution without systemic symptoms and anasarca. Were underwent a ganglionic biopsy with histopathology report of Hodgkin's disease mixed cellular variety and renal biopsy with histopathology report of minimal change disease. The patient present remission of nephrotic syndrome in simultaneous form at the control of the disease. In the reported cases of nephrotic syndrome associated with Hodgkin's disease it not clear the physiopathology. In this patient were realized immunologic studies of renal tissues to treat to find a possible mechanism of action of the neoplastic cells on the basal glomerular membrane but we can not found.