Pharmacokinetics and Anti-Tumor Efficacy of PEGylated Liposomes Co-Loaded with Cisplatin and Mifepristone.

Although cisplatin is an effective chemotherapy drug used against many types of cancer, it has poor bioavailability, produces severe adverse effects, and frequently leads to tumor resistance. Consequently, more effective formulations are needed. The co-administration of cisplatin with mifepristone, which counters an efflux pump drug-resistance mechanism in tumor cells, has shown important synergism, but without resolving the problem of poor bioavailability. Specificity to tumor tissue and bioavailability have been improved by co-encapsulating cisplatin and mifepristone in a liposomal formulation (L-Cis/MF), which needs further research to complete pre-clinical requirements. The aim of this current contribution was to conduct a pharmacokinetic study of cisplatin and mifepristone in male Wistar rats after administration of L-Cis/MF and the conventional (unencapsulated) formulation. Additionally, the capacity of L-Cis/MF to reduce tumor growth in male nude mice was evaluated following the implantation of xenografts of non-small-cell lung cancer. The better pharmacokinetics (higher plasma concentration) of cisplatin and mifepristone when injected in the liposomal versus the conventional formulation correlated with greater efficacy in controlling tumor growth. Future research on L-Cis/MF will characterize its molecular mechanisms and apply it to other types of cancer affected by the synergism of cisplatin and mifepristone.

The Therapeutic Potential of Chemo/Thermotherapy with Magnetoliposomes for Cancer Treatment.

Cancer represents a very grave and quickly growing public health problem worldwide. Despite the breakthroughs in treatment and early detection of the disease, an increase is projected in the incidence rate and mortality during the next 30 years. Thus, it is important to develop new treatment strategies and diagnostic tools. One alternative is magnetic hyperthermia, a therapeutic approach that has shown promising results, both as monotherapy and in combination with chemo- and radiotherapy. However, there are still certain limitations and questions with respect to the safety of the systemic administration of magnetic nanoparticles. To deal with these issues, magnetoliposomes were conceived as a new generation of liposomes that incorporate superparamagnetic nanoparticles and oncological pharmaceuticals within their structure. They have the advantage of targeted and selective drug delivery to the diseased organs and tissues. Some of them can avoid the immune response of the host. When exposed to a magnetic field of alternating current, magnetoliposomes produce hyperthermia, which acts synergistically with the released drug. The aim of the present review is to describe the most recent advances in the use of magnetoliposomes and point out what research remains to be done for their application to chemo-thermal therapy in cancer patients.

Ketoconazole Reverses Imatinib Resistance in Human Chronic Myelogenous Leukemia K562 Cells.

Chronic myeloid leukemia (CML) is a hematologic disorder characterized by the oncogene BCR-ABL1, which encodes an oncoprotein with tyrosine kinase activity. Imatinib, a BCR-ABL1 tyrosine kinase inhibitor, performs exceptionally well with minimal toxicity in CML chemotherapy. According to clinical trials, however, 20-30% of CML patients develop resistance to imatinib. Although the best studied resistance mechanisms are BCR-ABL1-dependent, P-glycoprotein (P-gp, a drug efflux transporter) may also contribute significantly. This study aimed to establish an imatinib-resistant human CML cell line, evaluate the role of P-gp in drug resistance, and assess the capacity of ketoconazole to reverse resistance by inhibiting P-gp. The following parameters were determined in both cell lines: cell viability (as the IC50) after exposure to imatinib and imatinib + ketoconazole, P-gp expression (by Western blot and immunofluorescence), the intracellular accumulation of a P-gp substrate (doxorubicin) by flow cytometry, and the percentage of apoptosis (by the Annexin method). In the highly resistant CML cell line obtained, P-gp was overexpressed, and the level of intracellular doxorubicin was low, representing high P-gp activity. Imatinib plus a non-toxic concentration of ketoconazole (10 µM) overcame drug resistance, inhibited P-gp overexpression and its efflux function, increased the intracellular accumulation of doxorubicin, and favored greater apoptosis of CML cells. P-gp contributes substantially to imatinib resistance in CML cells. Ketoconazole reversed CML cell resistance to imatinib by targeting P-gp-related pathways. The repurposing of ketoconazole for CML treatment will likely help patients resistant to imatinib.

Mifepristone Repurposing in Treatment of High-Grade Gliomas.

Glioma is the most common and aggressive primary tumor of the central nervous system. The standard treatment for malignant gliomas is surgery followed by chemoradiotherapy. Unfortunately, this treatment has not produced an adequate patient response, resulting in a median survival time of 12-15 months and a 5-year overall survival of <5%. Although new strategies have been sought to enhance patient response, no significant increase in the global survival of glioma patients has been achieved. The option of developing new drugs implies a long and costly process, making drug repurposing a more practical alternative for improving glioma treatment. In the last few years, researchers seeking more effective cancer therapy have pursued the possibility of using anti-hormonal agents, such as mifepristone. The latter drug, an antagonist for progesterone and glucocorticoid receptors, has several attractive features: anti-tumor activity, low cytotoxicity to healthy cells, and modulation of the chemosensitivity of several cancer cell lines in vitro. Hence, the addition of mifepristone to temozolomide-based glioblastoma chemotherapy may lead to a better patient response. The mechanisms by which mifepristone enhances glioma treatment are not yet known. The current review aims to discuss the potential role of mifepristone as an adjuvant drug for the treatment of high-grade gliomas.

Liposomes Co-Encapsulating Cisplatin/Mifepristone Improve the Effect on Cervical Cancer: In Vitro and In Vivo Assessment.

Cervical cancer is usually diagnosed in the later stages despite many campaigns for early detection and continues to be a major public health problem. The standard treatment is cisplatin-based chemotherapy plus radiotherapy, but patient response is far from ideal. In the research for new drugs that enhance the activity of cisplatin, different therapeutic agents have been tested, among them the antiprogestin mifepristone. Nevertheless, the efficacy of cisplatin is limited by its low specificity for tumor tissue, which causes severe side effects. Additionally, cervical tumors often become drug resistant. These problems could possibly be addressed by the use of liposome nanoparticles to encapsulate drugs and deliver them to the target. The aim of this study was to prepare liposome nanoparticles that co-encapsulate cisplatin and mifepristone, evaluate their cytotoxicity against HeLa cells and in vivo with subcutaneous inoculations of xenografts in nu/nu mice, and examine some plausible mechanisms of action. The liposomes were elaborated by the reverse-phase method and characterized by physicochemical tests. The nanoparticles had a mean particle size of 109 ± 5.4 nm and a Zeta potential of -38.7 ± 1.2 mV, the latter parameter indicating a stable formulation. These drug-loaded liposomes significantly decreased cell viability in vitro and tumor size in vivo, without generating systemic toxicity in the animals. There was evidence of cell cycle arrest and increased apoptosis. The promising results with the co-encapsulation of cisplatin/mifepristone warrant further research.

Liposomes Loaded with Cisplatin and Magnetic Nanoparticles: Physicochemical Characterization, Pharmacokinetics, and In-Vitro Efficacy.

With the aim improving drug delivery, liposomes have been employed as carriers for chemotherapeutics achieving promising results; their co-encapsulation with magnetic nanoparticles is evaluated in this work. The objective of this study was to examine the physicochemical characteristics, the pharmacokinetic behaviour, and the efficacy of pegylated liposomes loaded with cisplatin and magnetic nanoparticles (magnetite) (Cis-MLs). Cis-MLs were prepared by a modified reverse-phase evaporation method. To characterize their physicochemical properties, an evaluation was made of particle size, ζ-potential, phospholipid and cholesterol concentration, phase transition temperature (Tm), the encapsulation efficiency of cisplatin and magnetite, and drug release profiles. Additionally, pharmacokinetic studies were conducted on normal Wistar rats, while apoptosis and the cytotoxic effect were assessed with HeLa cells. We present a method for simultaneously encapsulating cisplatin at the core and also embedding magnetite nanoparticles on the membrane of liposomes with a mean vesicular size of 104.4 ± 11.5 nm and a ζ-potential of -40.5 ± 0.8 mV, affording a stable formulation with a safe pharmacokinetic profile. These liposomes elicited a significant effect on cell viability and triggered apoptosis in HeLa cells.

Determination of Liposomal Cisplatin by High-Performance Liquid Chromatography and Its Application in Pharmacokinetic Studies.

Liposomes have been employed as carriers for antineoplastic drugs to improve delivery. We describe an HPLC-UV method for determining cisplatin levels in liposomal and biological samples, which represents an attractive alternative to the widely used flame atomic absorption spectroscopy. Liposomal cisplatin was extracted from liposomes, plasma and tissue samples by using acetonitrile and separated on a Symmetry C18 column. The mobile phase was a mixture of water, methanol and acetonitrile, and detection was performed at 254 nm. The method was linear in the range of 0.5-10 µg/mL. Using this method, cisplatin concentration was measured in plasma, kidney, liver and tumor at different times post-administration of liposomal cisplatin. This method is proved suitable for measuring the levels of cisplatin encapsulated in a liposomal system, in plasma or tissue samples of experimental animals, after intravenous administration of liposomal cisplatin. Owing to the small plasma volume employed, a complete pharmacokinetic study can be done with a single animal.

Synergic Effect of α-Mangostin on the Cytotoxicity of Cisplatin in a Cervical Cancer Model.

Cervical cancer is the second leading cause of death among Mexican women. The treatment with cis-diamminedichloroplatinum (II) (CDDP) has some serious side effects. Alpha-mangostin (α-M), has a protective effect against CDDP-induced nephrotoxicity, as well as antioxidant, antitumor, and anti-inflammatory properties. Hence, we explored the in vitro and in vivo effect of α-M on human cervical cancer cell proliferation when combined with CDDP. In vitro, The cytotoxic effect of α-M and/or CDDP was measured by the 3-(3,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium assay. Meanwhile, apoptosis, reactive oxygen species (ROS) production, and the cell cycle were determined with flow cytometry. For α-M+CDDP treatment, both a coincubation and preincubation scheme were employed. In vivo, xenotransplantation was performed in female athymic BALB/c (nu/nu) mice, and then tumor volume and body weight were measured weekly, whereas α-M interfered with the antiproliferative activity of CDDP in the coincubation scheme, with preincubation with α-M+CDDP showing significantly greater cytotoxicity than CDDP or α-M alone, significantly inhibiting average tumor volume and preventing nephrotoxicity. This effect was accompanied by increased apoptosis and ROS production by HeLa cervical cancer cells, as well as an arrest in the cell cycle. These results suggest that α-M may be useful as a neoadjuvant agent in cervical cancer therapy.

Antihormonal agents as a strategy to improve the effect of chemo-radiation in cervical cancer: in vitro and in vivo study.

BACKGROUND: Over the past few years, the concurrent use of cisplatin-based chemotherapy and radiation therapy has dramatically improved the local response and increased overall survival in early-stage cervical cancer. However, for the advanced stages of the disease this standard treatment has proved insufficient. We investigated the capacity of Mifepristone and ICI 182,780, which are anti-progestin and anti-estrogen drugs, respectively, to act as chemo-radiosensitizing agents in cervical cancer cells and cervix xenografts. METHODS: The effect of chemo-radiation alone or combined with Mifepristone or ICI 182,780 was evaluated in HeLa cells and with tumor growth in cervix xenografts. After concomitant chemo-radiotherapy, the effect of each of these antihormonal agents on apoptosis (determined by Annexing V assay) and the cell cycle phases were determined by flow cytometry. The expression of angiogenic factor VEGF in tumor samples was determined using quantitative RT-PCR analysis of VEGF gene expression. RESULTS: Compared to radiation alone or radiation/cisplatin therapy, there was significantly higher cytotoxicity and a greater antitumoral effect with the combined application of radiation/cisplatin and Mifepristone or ICI 182,780. Analyses of the apoptosis and cell cycle demonstrated changes only with ICI, not with Mifepristone, when was applied in combination with radiation/cisplatin. The analysis of VEGF mRNA expression levels in tumors at the end of the study demonstrated a significant inhibition, compared to radiation only or the radiation/cisplatin treatment, after concurrent chemo-radiotherapy and each one of the antihormonal drugs. CONCLUSION: Mifepristone and ICI 182,780 may be potentially promising chemo-radiosensitizing compounds to be used in combination with ionizing irradiation and cisplatin in the treatment of patients with advanced cervical cancer.

Mifepristone improves chemo-radiation response in glioblastoma xenografts.

BACKGROUND: We have investigated the ability of Mifepristone, an anti-progestin and anti-glucocorticoid drug, to modulate the antitumor effect of current standard clinical treatment in glioblastoma xenografts. METHODS: The effect of radiation alone or combined with Mifepristone and Temozolamide was evaluated on tumor growth in glioblastoma xenografts, both in terms of preferentially triggering tumor cell death and inhibiting angiogenesis. Tumor size was measured once a week using a caliper and tumor metabolic-activity was carried out by molecular imaging using a microPET/CT scanner. The effect of Mifepristone on the expression of angiogenic factors after concomitant radio-chemotherapy was determined using a quantitative real-time PCR analysis of VEGF gene expression. RESULTS: The analysis of the data shows a significant antitumoral effect by the simultaneous administration of radiation-Mifepristone-Temozolamide in comparison with radiation alone or radiation-Temozolamide. CONCLUSION: Our results suggest that Mifepristone could improve the efficacy of chemo-radiotherapy in Glioblastoma. The addition of Mifepristone to standard radiation-Temozolamide therapy represents a potential approach as a chemo-radio-sensitizer in treating GBMs, which have very limited treatment options.

Cisplatin cytotoxicity is increased by mifepristone in cervical carcinoma: an in vitro and in vivo study.

We investigated the ability of mifepristone, an anti-progestin drug, to modulate the cytotoxic effect of cisplatin in two cervical cancer cell lines and in human xenograft cervical tumors. The effect of cisplatin alone or combined with mifepristone on cellular proliferation was studied with the XTT assay which use a tetrazolium dye {sodium3'-[1-(phenylamino-carbonyl)-3,4-tetrazolium],XTT}. Before and after treatment with mifepristone, the intracellular accumulation of cisplatin in cancer cells and tumors of mice was evaluated by HPLC. The expression of Bcl-2 and Bax genes was also assessed by a reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting. In addition, single agents and combination treatment in vivo studies were performed with the xenograft cervical model. Tumor measurements were carried out weekly. Analysis of the data by the isobologram method shows a synergistic antiproliferative effect produced by the combination of mifepristone with cisplatin only in the HeLa cervical cancer cell line but not in CaSki cells. The effect of mifepristone on cytotoxicity of cisplatin could be mediated, at least partially, by an increase of intracellular cisplatin accumulation, but not by changes in Bcl-2/Bax gene relation expression in these cells. In vivo studies showed that the combination of these agents has a significant antitumor activity against HeLa xenograft tumors. Our results suggest that mifepristone can improve the efficacy of the antiproliferative effect of cisplatin in vitro and in vivo. This anti-hormonal drug therapy may be a useful candidate for further evaluation in combination with other antineoplastic drugs in the treatment of cancer, particularly with cisplatin.

Use of an orthovoltage X-ray treatment unit as a radiation research system in a small-animal cancer model.

BACKGROUND: We explore the use of a clinical orthovoltage X-ray treatment unit as a small-animal radiation therapy system in a tumoral model of cervical cancer. METHODS: Nude mice were subcutaneously inoculated with 5 x 106 HeLa cells in both lower limbs. When tumor volume approximated 200 mm3 treatment was initiated. Animals received four 2 mg/kg intraperitoneal cycles (1/week) of cisplatin and/or 6.25 mg/kg of gemcitabine, concomitant with radiotherapy. Tumors were exposed to 2.5 Gy/day nominal surface doses (20 days) of 150 kV X-rays. Lead collimators with circular apertures (0.5 to 1.5 cm diameter) were manufactured and mounted on the applicator cone to restrict the X-ray beam onto tumors. X-ray penetration and conformality were evaluated by measuring dose at the surface and behind the tumor lobe by using HS GafChromic film. Relative changes in tumor volume (RTV) and a clonogenic assay were used to evaluate the therapeutic response of the tumor, and relative weight loss was used to assess toxicity of the treatments. RESULTS: No measurable dose was delivered outside of the collimator apertures. The analysis suggests that dose inhomogeneities in the tumor reach up to +/- 11.5% around the mean tumor dose value, which was estimated as 2.2 Gy/day. Evaluation of the RTV showed a significant reduction of the tumor volume as consequence of the chemoradiotherapy treatment; results also show that toxicity was well tolerated by the animals. CONCLUSION: Results and procedures described in the present work have shown the usefulness and convenience of the orthovoltage X-ray system for animal model radiotherapy protocols.

Tuberculosis in the transplant candidate: importance of early diagnosis and treatment.

BACKGROUND: Transplantation is contraindicated in candidates with active tuberculosis. The present study was undertaken to determine the clinical manifestations of tuberculosis in the transplant candidate and the prognosis of cases that inadvertently undergo transplantation. METHODS: This study was a retrospective study of tuberculosis cases diagnosed among 3,889 transplant candidates. All cases were diagnosed from respiratory or tissue samples obtained in the pretransplant period or during transplantation. RESULTS: We observed 7 cases (0.18%) of active tuberculosis among 3,889 candidates. Two patients had a history of tuberculosis. Tuberculosis was frequently asymptomatic. Three patients had extrapulmonary tuberculosis. Chest radiographs showed residual fibrotic lesions in three patients and noncavitated consolidation in two patients. All of the patients in which the purified protein derivative test was performed were anergic. All patients that inadvertently underwent transplantation were cured. CONCLUSIONS: Aggressive management is required to prevent tuberculosis in transplant candidates. Patients that inadvertently undergo transplantation can be effectively treated when diagnosed early.

Frequency of visceral leishmaniasis relapses in human immunodeficiency virus-infected patients receiving highly active antiretroviral therapy.

There are contradictory data about whether highly active antiretroviral therapy (HAART) prevents visceral leishmaniasis (VL) relapses in human immunodeficiency virus type 1 (HIV-1)-infected patients. The aim of this study was to assess the frequency of VL relapses in individuals receiving HAART. Thirty-one patients who received HAART after developing VL were included in a retrospective cohort study. Ten of them received secondary chemoprophylaxis and the rest did not. Eight (38%) patients without secondary chemoprophylaxis showed a VL relapse. None of the seven subjects with VL relapses and 6 of 11 without recurrence (P = 0.038), in whom all scheduled data were available, showed an increase of more than 100 CD4+ cells/mm(3) during the follow-up. Patients with relapse showed higher levels of HIV RNA viral load at their last visit (P = 0.047). The frequency of VL relapses in patients receiving HAART is high. Relapses of VL are observed only in individuals with uncontrolled HIV replication and/or poor immunologic responses.

Salmonella meningitis in adults infected with HIV: case report and review of the literature.

We report a case of Salmonella infantis meningitis in a patient infected with HIV who was successfully treated with 4 weeks of therapy and has had no relapses after 12 months of follow-up. Only 10 episodes of Salmonella species meningitis in patients infected with HIV are reported in the literature.

Tuberculosis of the pancreas: report of two cases and review of the literature.

Tuberculosis of the pancreas is a clinical entity rarely described in the literature. The pancreas is biologically protected from infection by Mycobacterium tuberculosis, probably because of the presence of pancreatic enzymes that interfere with the seeding of M. tuberculosis. However, when pathogens are able to overcome the resistance, they can have diverse presentations, such as pancreatic masses that can mimic carcinoma, obstructive jaundice, pancreatitis, and gastrointestinal bleeding. Herein we describe 2 cases of pancreatic tuberculosis that presented as multicystic masses, and we review the literature to describe the diverse clinical manifestations of this condition.

Prevención de infecciones en pacientes inmunodeprimidos / Prevention of infections in inmunodeprimidos

Expone que las infecciones en inmunodeprimidos tienen una alta morbilidad y mortalidad, motivo por el cual la prevención de estas infecciones es de suma importancia. Este propósito es tanto más importante en pacientes cuyas defensas inmunológicas están comprometidas, ya sea por enfermedades o terapia inmunosupresora. Las infecciones en pacientes inmunodeprimidos se originan de la flora endógena en el 85xcto de los casos y la mitad de estos microorganismos son adquiridos del ambiente hospitalario. El simple acto de lavarse las manos antes y después de examinar cada paciente tiene una importancia muy grande, profilaxis con antibioticoterapia es de importancia también, al igual que mejorar las defensas del huésped.

Reacciones fébriles post-transfusionales / Post-transfusionales febrile reactions

Actualmente es muy común el uso de sangre y productos derivados de la sangre en el paciente con enfermedades neoplásicas. Depresión medular con disminución de las células sanguíneas es del manejo diario de pacientes oncológicos, motivo por el cual los pacientes están sujetos a reacciones post-transfusionales. Estas reacciones pueden ser secundarias a procesos infecciosos asociados con la transfusión sanguínea o a consecuencia de fiebre no infecciosas post-transfusionales. En este artículo se revisará el diagnóstico diferencial de aquella fiebre que aparece a consecuencia de la terapia transfusional.