The Impact of Sidedness on the Efficacy of Anti-EGFR-Based First-Line Chemotherapy in Advanced Colorectal Cancer Patients in Real-Life Setting-A Nation-Wide Retrospective Analysis (RACER)

Anti-EGFR antibodies combined with chemotherapy doublets are a cornerstone of the upfront treatment of colorectal cancer. RAS and BRAF mutations are established negative predictive factors for such therapy. The primary tumour located in the proximal colon has recently emerged as another negative predictive factor. We have conducted a retrospective multicentre study to collect data on real-world population characteristics, practice patterns, and outcomes in patients with metastatic colorectal cancer treated in a first-line setting with either cetuximab or panitumumab in combination with either FOLFOX or FOLFIRI chemotherapy. The presented analysis focuses on the impact of the primary tumour location. 126 of 842 patients analysed (15.0%) had proximal primary. It was associated with a lower BMI at diagnosis, mucinous histology, and peritoneal metastases. It was also associated with inferior treatment outcomes in terms of response ratio: 59.4% vs. 74.22% (odds ratio [OR] 0.51, 95% CI 0.33-0.78, p = 0.010), and median depth of response: -36.7% vs. -50.0% (p = 0.038). There was only a borderline non-significant trend for inferior PFS in patients with proximal tumours. OS data was incomplete. The presented analysis confirms the negative impact of tumour sidedness on the efficacy of an upfront anti-EGFR-chemotherapy combination and provides valuable data on real-world population characteristics.

Association of dietary intake of polyphenols, lignans, and phytosterols with immune-stimulating microbiota and COVID-19 risk in a group of Polish men and women

Objectives

Devastating consequences of COVID-19 disease enhanced the role of promoting prevention-focused practices. Among targeted efforts, diet is regarded as one of the potential factors which can affect immune function and optimal nutrition is postulated as the method of augmentation of people's viral resistance. As epidemiological evidence is scarce, the present study aimed to explore the association between dietary intake of total polyphenols, lignans and plant sterols and the abundance of immunomodulatory gut microbiota such as Enterococcus spp. and Escherichia coli and the risk of developing COVID-19 disease.

Methods

Demographic data, dietary habits, physical activity as well as the composition of body and gut microbiota were analyzed in a sample of 95 young healthy individuals. Dietary polyphenol, lignan and plant sterol intakes have been retrieved based on the amount of food consumed by the participants, the phytochemical content was assessed in laboratory analysis and using available databases.

Results

For all investigated polyphenols and phytosterols, except campesterol, every unit increase in the tertile of intake category was associated with a decrease in the odds of contracting COVID-19. The risk reduction ranged from several dozen percent to 70 %, depending on the individual plant-based chemical, and after controlling for basic covariates it was statistically significant for secoisolariciresinol (OR = 0.28, 95% CI: 0.11-0.61), total phytosterols (OR = 0.47, 95% CI: 0.22-0.95) and for stigmasterols (OR = 0.34, 95% CI: 0.14-0.72). We found an inverse association between increased β-sitosterol intake and phytosterols in total and the occurrence of Escherichia coli in stool samples outside reference values, with 72% (OR = 0.28, 95% CI: 0.08-0.86) and 66% (OR = 0.34, 95% CI: 0.10-1.08) reduced odds of abnormal level of bacteria for the highest compared with the lowest tertile of phytochemical consumption. Additionally, there was a trend of more frequent presence of Enterococcus spp. at relevant level in people with a higher intake of lariciresinol.

Conclusion

The beneficial effects of polyphenols and phytosterols should be emphasized and these plant-based compounds should be regarded in the context of their utility as antiviral agents preventing influenza-type infections.

Clinical Characterization of Targetable Mutations (BRAF V600E and KRAS G12C) in Advanced Colorectal Cancer-A Nation-Wide Study

BRAF V600E and KRAS mutations that occur in colorectal cancer (CRC) define a subpopulation of patients with an inferior prognosis. Recently, the first BRAF V600E-targeting therapy has been approved and novel agents targeting KRAS G12C are being evaluated in CRC. A better understanding of the clinical characteristics of the populations defined by those mutations is needed. We created a retrospective database that collects clinical characteristics of patients with metastatic CRC evaluated for RAS and BRAF mutations in a single laboratory. A total of 7604 patients tested between October 2017 and December 2019 were included in the analysis. The prevalence of BRAF V600E was 6.77%. Female sex, primary in the right colon, high-grade, mucinous, signet cell, partially neuroendocrine histology, perineural and vascular invasion, and surgical tissue sample were factors associated with increased mutation rates. The prevalence of KRAS G12C was 3.11%. Cancer of primary origin in the left colon and in samples from brain metastases were associated with increased mutation rates. The high prevalence of the BRAF V600E mutation in cancers with a neuroendocrine component identifies a potential candidate population for BRAF inhibition. The association of KRAS G12C with the left part of the intestine and brain metastases of CRC are new findings and require further investigation.

Metronomic Chemo-Endocrine Therapy (FulVEC) as a Salvage Treatment for Patients with Advanced, Treatment-Refractory ER+/HER2-Breast Cancer-A Retrospective Analysis of Consecutive Patients Data

BACKGROUND

Breast cancer, with 2.3 million new cases and 0.7 million deaths every year, represents a great medical challenge worldwide. These numbers confirm that approx. 30% of BC patients will develop an incurable disease requiring life-long, palliative systemic treatment. Endocrine treatment and chemotherapy administered in a sequential fashion are the basic treatment options in advanced ER+/HER2- BC, which is the most common BC type. The palliative, long-term treatment of advanced BC should not only be highly active but also minimally toxic to allow long-term survival with the optimal quality of life. A combination of metronomic chemotherapy (MC) with endocrine treatment (ET) in patients who failed earlier lines of ET represents an interesting and promising option.

METHODS

The methodology includes retrospective data analyses of pretreated, metastatic ER+/HER2- BC (mBC) patients who were treated with the FulVEC regimen combining fulvestrant and MC (cyclophosphamide, vinorelbine, and capecitabine).

RESULTS

Thirty-nine previously treated (median 2 lines 1-9) mBC patients received FulVEC. The median PFS and OS were 8.4 and 21.5 months, respectively. Biochemical responses (CA-15.3 serum marker decline ≥50%) were observed in 48.7%, and any increase in CA-15.3 was observed in 23.1% of patients. The activity of FulVEC was independent of previous treatments with fulvestrant of cytotoxic components of the FulVEC regimen. The treatment was safe and well tolerated.

CONCLUSIONS

Metronomic chemo-endocrine therapy with FulVEC regimen represents an interesting option and compares favorably with other approaches in patients' refractory to endocrine treatments. A phase II randomized trial is warranted.

Polish Consensus on Gastric Cancer Diagnosis and Treatment – Update 2022

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Abstract CT179: Safety and effectiveness of plasmapheresis-based elimination of soluble TNFα receptors combined with chemotherapy in advanced, chemorefractory triple-negative breast cancer patients - a phase I/II study (CP7-005)

Introduction: Tumor necrosis factor-alpha (TNFα) is a pleiotropic cytokine with known antitumor activity, produced mainly by activated immune cells. Cancer cells neutralize TNFα by shedding soluble TNF receptors 1&2 (sTNF-Rs), which act as TNFα-binding decoys, promoting cancer cell proliferation, survival, and chemoresistance. Immunopheresis® employs therapeutic apheresis with the selective immunoadsorption LW-02 column (LW-02) for treating solid malignancies. LW-02-based Immunopheresis (granted FDA Breakthrough Device Designation and a CE Mark for mTNBC) selectively removes sTNF-Rs from plasma, permitting TNFα to bind to membrane-bound TNF-Rs, activating intracellular death pathways, and also modulate T-cell-mediated immune activity. Part A data of our phase I/II clinical trial in metastatic, chemorefractory, triple-negative breast cancer (mTNBC) patients (NCT04004910) confirmed that LW-02-based Immunopheresis monotherapy is safe and well-tolerated, with signs of disease stabilization (SD) in patients treated >4 weeks. Here we present interim data on the safety and preliminary efficacy of LW-02 Immunopheresis combined with chemotherapy.

Methods: LW-02 Immunopheresis (3x/week for 16 weeks) is combined with a weekly paclitaxel (80 mg/m2)+carboplatin (AUC 2) regimen in patients with mTNBC; treatment is continued past 16 weeks in clinical and/or objective responders. Primary endpoints are safety and tolerability. Secondary endpoints assessed in patients treated >4 weeks include overall survival, tumor response according to RECIST, rate of CNS progression and quality-of-life.

Results: Of 11 patients enrolled in Part B of the study, 7 patients were treated for >4 weeks. The ORR was 18% (1CR, 1PR) with one additional patient experiencing SD; the ORR and CBR in patients treated >4 weeks were 29% and 43%, respectively. The median OS, to date, is 18.6 weeks and 26.7 weeks in the group treated >4 weeks. The rate of CNS progression (new or preexisting lesions) appears lower than expected. The most common adverse events (AEs) were chemotherapy-induced myelotoxicity (anemia, neutropenia, thrombocytopenia) and transient electrolyte abnormalities. Thirty-one serious AEs (SAEs) were reported for all 11 patients, 15 (48.4%) were transfusion requiring anemias. Of the SAEs, 3 (9.6%) were judged to have a potential causal relationship to LW-02 column Immunopheresis.

Conclusion: LW-02-based Immunopheresis combined with weekly chemotherapy is generally safe, well-tolerated and highly effective in specific sTNFR subtraction on a longer-term basis, with promising signals of clinical benefit in heavily pretreated mTNBC patients (median 3.3 [2-5] prior lines of systemic therapy). Further clinical evaluation of the antitumor activity of LW-02-based immunopheresis combined with low-dose chemotherapy is ongoing with a focus on quality-of-life and prevention of CNS disease progression, the latter especially important in chemorefractory mTNBC, given the high prevalence of CNS involvement.

Citation Format: Piotr Jan Wysocki, Adam Ostrowski, Robert Segal, Victoria Manax, Pawel Potocki, Kamil Konopka, Lukasz Kwinta, Paulina Fraczek, Maciej Lubas, Mateusz Lobacz, Lawrence Florin. Safety and effectiveness of plasmapheresis-based elimination of soluble TNFα receptors combined with chemotherapy in advanced, chemorefractory triple-negative breast cancer patients - a phase I/II study (CP7-005) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT179.

Reduction of Cancer-Induced Thrombocytosis as a Biomarker of Improved Outcomes in Advanced Gastric Cancer

BACKGROUND

Interplay between non-specific inflammatory reaction and tumor microenvironment in gastric cancer (GC) can be measured indirectly by assessing fluctuations in concentration of platelets. Cytotoxic chemotherapy affects these morphotic elements directly by inducing myelosuppression. It was hypothesized that chemotherapy not only directly affects malignant cells, but also through immunomodulation related to myelosuppression.

METHODS

Metastatic GC patients (N: 155) treated with chemotherapy +/- trastuzumab were enrolled in this retrospective study. Platelet pretreatment concentration (PLT-count) and the deepest level of platelet reduction, as well as other inflammatory and general confounders were collected in the first 12 weeks of treatment (PLT-red). Martingale residuals were used to visualize the relationship between PLT-count, PLT-red, and overall survival (OS). Multiple multivariate Cox regression models were built to assess the impact of platelet reduction on OS and progression-free survival (PFS).

RESULTS

Reduction of PLT (PLT-red) to 60% of baseline concentration was associated with improved survival rates (HR = 0.60, p = 0.026 for OS and HR 0.56, p = 0.015 for PFS). Cross-classification into four groups based on PLT-count (high vs low) and PLT-red (high vs low) showed significantly worse survival rates in both high PLT-count (HR = 3.60, p = 0.007 for OS and HR = 2.97, p = 0.024 for PFS) and low PLT-count (HR = 1.75, p = 0.035 for OS and HR = 1.80, p = 0.028 for PFS) patients with insufficient platelets reduction.

CONCLUSION

Thrombocytosis reduction represents a novel, clinically important, prognostic factor for OS and PFS in patients with stage IV GC.

Combined Neutrophil-to-Lymphocyte and Platelet-Volume-to-Platelet Ratio (NLR and PVPR Score) Represents a Novel Prognostic Factor in Advanced Gastric Cancer Patients

BACKGROUND

Chemotherapy is a cornerstone of treatment in advanced gastric cancer (GC) with a proven impact on overall survival, however, reliable predictive markers are missing. The role of various inflammatory markers has been tested in gastric cancer patients, but there is still no general consensus on their true clinical applicability. High neutrophil-to-lymphocyte (NLR) and low (medium)-platelets-volume-to-platelet ratio (PVPR) are known markers of unspecific immune system activation, correlating significantly with outcomes in advanced GC patients.

METHODS

Metastatic GC patients (N:155) treated with chemotherapy +/- trastuzumab were enrolled in this retrospective study. Pre-treatment NLR and PVPR, as well as other inflammatory markers were measured in peripheral blood. Univariate Cox regression was conducted to find markers with a significant impact on overall survival (OS) and progression-free survival (PFS). Spearman correlation and Cohen's kappa was used to analyze multicollinearity. Multiple multivariable Cox regression models were built to study the combined impact of NLR and PVPR, as well as other known prognostic factors on OS.

RESULTS

Elevated NLR was significantly associated with increased risk of death (HR = 1.95; 95% CI: 1.17-3.24), and lower PVPR was significantly associated with improved outcomes (HR = 0.53; 95% CI: 0.32-0.90). A novel inflammatory marker, based on a combination of NLR and PVPR, allows for the classification of GC patients into three prognostic groups, characterized by median OS of 8.4 months (95% CI 5.8-11.1), 10.5 months (95% CI 8.8-12.1), and 15.9 months (95% CI 13.5-18.3).

CONCLUSION

The NLR and PVPR score (elevated NLR and decreased PVPR) is a marker of detrimental outcome of advanced GC patients treated with chemotherapy.

Abstract CT135: Extracorporeal pulldown of soluble TNFRs to unleash the activity of endogenous TNFα in chemorefractory triple-negative breast cancer patients - first-in-human experience

Introduction: Tumor necrosis factor-alpha (TNFα) is a pleiotropic cytokine, with known antitumor activity, produced mainly by activated immune cells. Cancer cells can neutralize TNFα by shedding soluble TNF receptors 1&2 (sTNFRs), which act as TNFα-binding decoys. In addition, sTNFRs can directly promote proliferation, survival, and chemoresistance of cancer cells by binding to membrane-bound TNFα and initiating retrograde signaling. Therefore, the reduction of systemic and intratumoral concentrations of sTNFRs represents a novel and unique anticancer strategy, since systemic recombinant TNFα treatment strategies require very high doses to achieve antitumor activity, and are feasible only in an isolated limb perfusion setting.

Methods: We developed an extracorporeal sTNFR-scavenging approach, Immunopheresis™, which combines apheresis with the novel LW-02 immunoadsorption column (LW-02) that employs a recombinant single chain TNFα (scTNF) as the sTNFR-scavenger ligand. The LW-02 column has received FDA breakthrough designation for potential treatment of advanced metastatic solid tumors, based on data from a comparative oncology study in canines with naturally occurring melanoma and solid tumors. For our first-in-human experience we chose to study patients with advanced, chemo-refractory metastatic triple-negative breast cancer (mTNBC) in a multi-center Phase I/II clinical trial (NCT04004910), assessing feasibility and safety of sTNFR-reduction, and preliminary clinical activity of LW-02-based immunopheresis alone and in combination with low-dose chemotherapy. Here we present data on the first cohort of mTNBC patients treated with LW-02 immunopheresis alone.

Results: Of 14 screened patients, due to ECOG PS deterioration in 4 pts, only 10 (median age - 52.9, ECOG≤1) underwent at least one LW-02 immunopheresis procedure involving processing of 2 plasma volumes (2PV). The highly specific LW-02 (no off-target capture) pulldown of sTNFRs exceeded 80%, leading to a ≥25% reduction in blood sTNFR levels after 2PV. Leaching of scTNF into circulation was minimal (<50 ng/min) and did not represent any hazard to patients. The most common AEs (mainly CTCAE G1-2) were transient electrolyte abnormalities, anemia, pain and leucopenia. Serious AEs were reported in 80% of patients but no SAE was related to the experimental treatment. Median duration of LW-02 immunopheresis treatment was 2.25 months in these patients who had failed multiple prior chemotherapy lines (median=4). Median survival was 4.38 months in patients receiving ≥4 wks of immunopheresis.

Conclusion: The LW-02-column immunopheresis procedure was shown to be generally safe and highly effective in specific sTNFR subtraction on a longer-term basis, with initial signals of clinical benefit in heavily pretreated mTNBC patients. Further clinical evaluation of the antitumor activity of LW02-based immunopheresis combined with low-dose chemotherapy is ongoing.

Citation Format: Piotr J. Wysocki, Adam Ostrowski, Robert Segal, Pawel M. Potocki, Lukasz Kwinta, Kamil Konopka, Lawrence B. Florin, Stephen M. Prince. Extracorporeal pulldown of soluble TNFRs to unleash the activity of endogenous TNFα in chemorefractory triple-negative breast cancer patients - first-in-human experience [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT135.

Clinical effectiveness and toxicity of second-line irinotecan in advanced gastric and gastroesophageal junction adenocarcinoma: a single-center observational study

BACKGROUND

Randomized clinical trials showed improved overall survival (OS) of advanced gastroesophageal adenocarcinoma (GEA) patients treated with second-line taxane or irinotecan. However, most data on irinotecan efficacy in this setting come from large Asian trials. We retrospectively analyzed clinical effectiveness and toxicity of irinotecan in a cohort of patients with advanced GEA treated in our department.

METHODS

Advanced GEA patients who received at least one cycle of second-line irinotecan were eligible for inclusion. Irinotecan was administered every 3 weeks at an initial dose of 250 mg/m² of body surface area with subsequent gradual (every 50 mg/m²) dose escalation up to 350 mg/m², in the case of good treatment tolerance. OS was estimated using the Kaplan-Meier method. A multivariate Cox regression analysis was used to examine the association between clinical and laboratory parameters and survival.

RESULTS

A total of 48 patients were identified. Median OS was 6.2 months [95% confidence interval (CI): 3.9-7.6]. In multivariate analysis, age < 65 years, baseline total lymphocyte count (TLC) < 1500/µl and presence of peritoneal metastases were associated with shorter OS. Most adverse events were grade 1-2 and included: anemia (52.3%), leukocytopenia (40.9%), neutropenia (59.1%), nausea (25.0%), vomiting (31.8%), diarrhea (31.8%), anorexia (29.5%) and fatigue (43.2%). Febrile neutropenia occurred in three patients (6.8%). Nine patients (20.5%) experienced a toxicity grade 3-4 of any kind.

CONCLUSIONS

This retrospective analysis confirms clinical effectiveness and manageable toxicity of second-line irinotecan in an unselected cohort of advanced GEA patients. Age < 65 years, baseline TLC < 1500/µl and presence of peritoneal metastases were independent prognostic factors associated with shorter OS.

Photodynamic Therapy in Dentistry

Photodynamic therapy (PDT), also known as photoradiation therapy, phototherapy, or photochemo-therapy, involves the use of a photoactive dye (photosensitizer) that is activated by exposure to light of a specific wavelength in the presence of oxygen. The transfer of energy from the activated photosensitizer to available oxygen results in the formation of toxic oxygen species, such as singlet oxygen and free radicals. These very reactive chemical species can damage proteins, lipids, nucleic acids, and other cellular components. Applications of PDT in dentistry are growing rapidly: the treatment of oral cancer, bacterial and fungal infection therapies, and the photodynamic diagnosis (PDD) of the malignant transformation of oral lesions. PDT has shown potential in the treatment of oral leukoplakia, oral lichen planus, and head and neck cancer. Photodynamic antimicrobial chemotherapy (PACT) has been efficacious in the treatment of bacterial, fungal, parasitic, and viral infections. The absence of genotoxic and mutagenic effects of PDT is an important factor for long-term safety during treatment. PDT also represents a novel therapeutic approach in the management of oral biofilms. Disruption of plaque structure has important consequences for homeostasis within the biofilm. Studies are now leading toward selective photosensitizers, since killing the entire flora leaves patients open to opportunistic infections. Dentists deal with oral infections on a regular basis. The oral cavity is especially suitable for PACT, because it is relatively accessible to illumination.

Evaluation of health-related quality of life and its main influencing factors in a Polish population of patients with bone metastases

PURPOSE

Regardless of cancer type, the skeleton is one of the most common sites for cancer spread. Health-related Quality of Life (HRQoL) can be considered a primary endpoint in clinical trials concerning cancer patients with palliative disease. The proper measurement of this endpoint requires valid and reliable instruments. The aim of this study was to evaluate HRQoL and its main influencing factors using validated EORTC tools - the QLQ-C30 and the QLQ-BM22 in Polish population of patients with skeletal metastases.

METHODS

Patients with bone metastases and histologically confirmed malignancy were qualified for the study. They filled out a personal questionnaire, the Polish version of the EORTC QLQ-C30 and its supplementary module QLQ-BM22. The influence of numerous socio-clinical factors such as age, gender, working status, level of education, performance status, primary location, and previous treatment received was assessed.

RESULTS

One hundred and ten patients (65 women) were enrolled into this study (mean age ±SD; 57.8±13.8). The most significant HRQoL issues were fatigue (59.29/100); pain (56.97/100) and insomnia (56.36/100). Men coped worse with pain (p=0.013), fatigue (p=0.050), nausea and vomiting (p=0.024) and financial difficulties (p=0.016) than women.

CONCLUSIONS

The main factors influencing HRQoL in Polish patients with bone metastases are fatigue, pain and insomnia, and as such should be a primary focus of patient-centered care in this group.

Cationic porphyrin-mediated photodynamic inactivation of Candida biofilms and the effect of miconazole

The formation of biofilms by Candida and the increasing resistance of Candida species to antifungals contribute to the high recurrence rates of denture stomatitis. This increase has stimulated an interest in antimicrobial photodynamic therapy (aPDT) as an alternative treatment. We examined the photoactivity of the porphyrin-based photosensitizer, TMP-1363, against biofilms of C. albicans, C. glabrata, C. tropicalis and C. parapsilosis, and the effect of the combined use of miconazole and aPDT. Biofilms of three American Type Culture Collection (ATCC) strains and four clinical isolates developed on poly(methyl methacrylate) (PMMA) disks, were incubated with miconazole, followed by treatment with TMP-1363 for 30 min at 37°C. The plates were exposed to broadband visible light at a distance of 10 cm to the plate, for 30 min (irradiance at the surface of the plate: 32.5 mW/cm2). The metabolic activity of the biofilms was measured by the XTT assay. ATCC strains and C. glabrata 7531/06 were not sensitive to TMP-aPDT, whereas the metabolic activities of the remaining three clinical isolates were reduced to 64.2 ± 5.5% of controls. Miconazole at 25 μg/ml decreased the viability of all strains except the ATTCC strain C. albicans MYA274; however its combination with aPDT was effective against this strain, suggesting a synergistic interaction. Effects of miconazole and aPDT on C. albicans MYA 2732, C. albicans 6122/06 were additive. With C. tropicalis and C. parapsilosis, the combined treatment had a higher, but not entirely additive, cytotoxic effect. The combined use of miconazole and TMP-aPDT is advantageous in the treatment of biofilms of a number of Candida species and strains, but not all. The molecular basis of this differential response is not known.

Anionic Liposomes Inhibit Human Immunodeficiency Virus Type 1 (HIV-1) Infectivity in CD4+ A3.01 and H9 Cells

Immunodeficiency viruses undergo fusion with liposomes containing anionic phospholipids (Larsen etal., 1990). We have investigated the effect of liposomes composed of cardiolipin, phosphatidylserine or phosphatidylinositol, on the infectivity of three strains of HIV-1 in A3.01 and H9 cells, measured by p24 (gag) production in the medium. The infectivity of HIV-1 in A3.01 or H9 cells was inhibited by the presence of cardiolipin liposomes during a 2 h infection period, with IC50's of 23.0, 4.8, and 5.0 μM phospholipid, respectively, for the different strains. Liposomes composed of phosphatidylserine or phosphatidylinositol were ineffective under similar conditions. However, prolonged pre-incubation of the virus with these liposomes also inhibited infectivity. Inhibition of virus binding to cells could not account for the inhibition of infectivity. We propose that the fusion products of HIV-1 and anionic liposomes are impaired in their ability to fuse with the plasma membrane.

Assessment of frequency and severity of hypomagnesemia in patients with metastatic colorectal cancer treated with cetuximab, with a review of the literature

Currently, there are a few systemic treatment options for patients with metastatic colorectal cancer (mCRC). Targeted therapy used in this setting includes the use of monoclonal antibodies, such as cetuximab or panitumumab, directed against epidermal growth factor receptor. The aim of the present study was to estimate the frequency and severity of hypomagnesemia among patients with mCRC treated with cetuximab. The data from the Department of Clinical Oncology, University Hospital of Krakow (Krakow, Poland), concerning 52 patients treated between 2009 and 2013 were collected. Of these, 27 patients fulfilled the inclusion criteria to enter this retrospective study. The National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0 were used to grade the level of hypomagnesemia. In total, 29.6% of all patients experienced hypomagnesemia during treatment, and the majority of cases were grade 1 (22.2%). There was no statistically significant correlation between magnesium (Mg) level and patient age, duration of treatment, localization of primary tumor or metastases, and the number of metastases. However, there was an upward trend in a logistic regression model showing that the risk of developing hypomagnesemia increases with age. Hypomagnesemia is a frequent problem among mCRC patients receiving cetuximab. It is essential to introduce guidelines regarding the monitoring of the Mg level and its supplementation in this group of patients.

Comparison of efficacy and tolerance of first-line palliative chemotherapy EOX and mDCF regimens in patients with locally advanced inoperable or metastatic gastric or gastroesophageal junction adenocarcinoma without overexpression of HER2 receptors

135

Background: The aim of the study was to compare efficacy and tolerance of first-line palliative chemotherapy EOX (epirubicin/oxaliplatin/capecitabine) and mDCF (docetaxel/cisplatin/5FU/leucovorin) regimens in patients with locally advanced inoperable or metastatic gastric or gastroesophageal junction adenocarcinoma without overexpression of HER2 receptors. Methods: Each chemotherapy regimen was assigned with 21 patients. Planned treatment consisted of 12 every-two-weeks mDCF cycles (docetaxel 40 mg/m2 day 1, leucovorin 400 mg/m2 day 1, 5FU 400 mg/m2 bolus day 1, 5FU 1000 mg/m2/d days 1 and 2, cisplatin 40 mg/m2 day 3) or 8 every-three-weeks EOX cycles (epirubicin 50mg/m2 day 1, oxaliplatin 130mg/m2 day 1, capecitabine 1250mg/m2/d days 1 to 21). The primary endpoint was overall survival in all patients who commenced at least one chemotherapy cycle. Results: Median progression-free survival was 5.8 months in EOX group and 7.5 months in mDCF group (p=0.11), and median overall survival was 8.5 months and 12.0 months respectively (p=0.219). Due to toxicity, patients in the EOX arm had more frequent reductions of cytostatics doses (42.9% vs 5.0%; p=0.009) as well as delays in the administration of subsequent chemotherapy cycles (81.0% vs 65.0%; p=0.424). Rates of all grade 3 or 4 adverse events were comparable between both arms (76.19% in the EOX vs 70.0% in the mDCF; p=1.000). Toxicities that occurred more frequently in the EOX group compared to mDCF group were: nausea (28.6% vs 5.0%; p=0.093), thromboembolic events (19.0% vs 10%; p=0.663) and grade 3 or 4 neutropenia (71.4% vs 55.0%; p=0.443). Conclusions: In this patients population with locally advanced inoperable or metastatic gastric or gastroesophageal junction adenocarcinoma without overexpression of HER2 receptors treatment with mDCF regimen was associated with a statistically non-significant 3.5 month longer median overall survival without increase in toxicity. Updated data will be presented.

Miconazole activity against Candida biofilms developed on acrylic discs

Oral candidiasis in the form of Candida-associated denture stomatitis (CaDS) is associated with Candida adhesion and biofilm formation on the fitting surface of poly (methyl methacrylate) (PMMA) dentures. Candida biofilms show considerable resistance to most conventional antifungal agents, a phenomenon that is considered a developmental-phase-specific event that may help explain the high recurrence rates associated with CaDS. The aim of this study was to examine the activity of miconazole towards in vitro-grown mature Candida biofilms formed on heat-cured PMMA discs as a standardized model. The effect of miconazole nitrate on Candida biofilms developed on acrylic discs was determined for C. albicans MYA-2732 (ATCC), C. glabrata MYA-275 (ATCC), and clinical isolates, C. albicans 6122/06, C. glabrata 7531/06, C. tropicalis 8122/06, and C. parapsilosis 11375/07. Candida biofilms were developed on heat-cured poly(methyl methacrylate) discs and treated with miconazole (0.5 - 96 μg/ml). The metabolic activity of the biofilms was measured by the XTT reduction assay. The minimum inhibitory concentrations (MICs) of miconazole against Candida species were determined by the microdilution method. The MICs for miconazole for the investigated strains ranged from 0.016-32 μg/ml. Treatment with miconazole resulted in a significant reduction of biofilm metabolic activity for all strains. The highest inhibition was observed at 96 μg/ml miconazole. In the case of C. glabrata MYA-275 and C. tropicalis 8122/06 this corresponded to 83.7% and 75.4% inhibition, respectively. The lowest reduction was observed for C. parapsilosis 11375/07-46.1%. For all Candida strains there was a strong correlation between MIC values and miconazole concentrations corresponding to a reduction of metabolic activity of the biofilm by 50%. Miconazole exhibits high antifungal activity against Candida biofilms developed on the surface of PMMA discs. The study provides support for the use of miconazole as an effective agent for the treatment of CaDS.

Metal particles in a ceramic matrix�?�scanning electron microscopy and transmission electron microscopy characterization

This paper is concerned with ceramic matrix (Al(2)O(3)) composites with introduced metal particles (Ni, Fe). The composites were obtained via sintering of powders under very high pressure (2.5 GPa). Scanning electron microscopy and transmission electron microscopy were chosen as the tools for the identification and description of the shape, size and distribution of the metal particles. The Al(2)O(3)-Ni composite contained agglomerates of the Ni particles surrounded by ceramic grains and nanometre-size Ni particles located inside the ceramic grains and at the ceramic grain boundaries. In the Al(2)O(3)-Fe composite, the Fe particles were mostly surrounded by ceramic grains. Moreover, holes left by the Fe particles were found. The high pressure used in the fabrication of the composites changed the shape of the metal and ceramic powder grains via plastic deformation.

Influence of antifungal polyenes on the adhesion of Candida albicans and Candida glabrata to human epithelial cells in vitro

Candidal adherence to mucosal surfaces is considered as the first step in the pathogenesis of oral candidiasis. We examined the effect of antifungal polyenes, amphotericin B, nystatin and natamycin, at sublethal and minimum inhibitory concentrations (MICs) on the adherence of Candida albicans and Candida glabrata to HeLa cervical carcinoma and HSC-3 oral squamous cell carcinoma cells. A total of six oral Candida isolates were used throughout the study. Two Candida strains, C. albicans (44990) and C. glabrata (MYA-275) were obtained from ATCC. Four Candida strains, C. albicans 19 and 24 and C. glabrata 15 and 21, were isolated from patients with documented Candida-associated denture stomatitis. Cells were either incubated with Candida in the presence of the drug, or pre-incubated with yeasts and exposed subsequently to the drug. In the drug-free controls, the mean number of C. albicans yeasts associated with HeLa cells obtained from all experiments (130.1+/-10.1 yeasts/mm(2)) was significantly greater than that for HSC-3 cells (114.7+/-10.1 yeasts/mm(2); P<0.025). For C. glabrata, the mean adherence to HeLa and HSC-3 cells was 84.4+/-5.5 and 84.4+/-3.3 yeasts/mm(2), respectively, and these values were not statistically different (P>0.4). Candidal adherence was significantly reduced when the tested polyenes were present during the "adherence phase". The obtained values were significantly different from the controls, except for the effect of nystatin at the MIC on the adherence of C. glabrata strain MYA-275 to HeLa cells (P<0.375). Amphotericin B had the highest effect against both Candida species, reducing adherence by approximately 50 and approximately 60%, at the MIC and sublethal concentrations, respectively. The susceptibility of cell-associated Candida to polyenes was decreased markedly and the treatment did not result in significant detachment of adherent yeasts. The reduction in adherence was between 2 and 10%, when compared to the drug-free controls. These findings suggest that sub-therapeutic levels of polyenes that are likely to persist in the oral cavity following topical treatment may modulate candidal colonization when present during the "adherence phase".

Delivery of novel macromolecular drugs against HIV-1

The development of new low molecular weight drugs against human immunodeficiency virus Type 1 (HIV-1) targets other than reverse transcriptase (RT) and protease, such as the integrase and the envelope glycoprotein, is likely to take many years. Macromolecular drugs, including antisense oligonucleotides, ribozymes, RNA decoys and transdominant mutant proteins, may be able to interfere with a relatively large number of viral targets, thereby decreasing the likelihood of the emergence of drug-resistant strains. It may also be relatively easy to alter the sequence of some of the macromolecular drugs to counter emerging drug-resistant viruses. The delivery of antisense oligonucleotides and ribozymes to HIV-1 infected or potentially infectable cells by antibody-targeted liposomes, certain cationic lipid formulations and pH-sensitive liposomes results in significant anti-HIV-1 activity. These carriers not only facilitate cytoplasmic delivery but also protect the drugs from nuclease digestion. Delivery of therapeutic genes (another form of macromolecular drug) to target cells is an important challenge of gene therapy. Following delivery by a viral vector, sufficient levels of gene expression must be maintained over an extended period of time to have therapeutic activity. Robust expression of therapeutically useful ribozymes, antisense, decoys and aptamers can be achieved by the use of Pol III expression systems. Moloney murine leukaemia virus- (MoMuLV), adeno-associated virus (AAV)-, or HIV-derived vectors expressing a variety of therapeutic genes have been used successfully to inhibit HIV-1 replication in cultured cells.

Rev-binding aptamer and CMV promoter act as decoys to inhibit HIV replication

We examined whether the antiviral effect of an HIV-1 Rev-binding aptamer [RBE(apt)] could be enhanced by a ribozyme directed against the HIV-1 env gene, and whether the antiviral activity was affected by different promoters. The efficacy of the aptamer and ribozyme DNAs was tested in HeLa cells co-transfected with the HIV-1 proviral clones, HXBDeltaBgl or pNL4-3, using transferrin-lipoplexes. The RBE(apt) and anti-env ribozyme genes were inserted into the pTZU6+27 plasmid, or constructed under the control of the human cytomegalovirus (CMV) or Rous sarcoma virus (RSV) promoters. The parental vector plasmids were used as controls. Co-transfection of the pTZU6+27 RBE(apt) plasmid with HXBDeltaBgl, or pNL4-3, at a weight ratio of 5:1, inhibited p24 production by 70 and 45%, respectively. The RSV RBE(apt) plasmid co-transfected with either HIV clone, at the same weight ratio, reduced viral production by 88%. The addition of the anti-env ribozyme to the RSV RBE(apt) did not enhance its antiviral activity. When the constructs were under the control of the CMV promoter, the expression of the HIV plasmids was very low and was independent of the presence of the RBE(apt). Thus, the effect of the RBE(apt) was strongly dependent on the promoter of the tested construct. The anti-HIV activity of the CMV RBE(apt) construct was non-specific, because co-transfection with either pCMV. SPORT-betagal or pCMVlacZ significantly suppressed HIV production from the HIV proviral clones. The reduction in p24 could not be attributed to the non-specific toxicity of the transfection procedure. Transfection of acutely HIV-infected HeLa-CD4 cells with pCMV.SPORT-betagal reduced the p24 level by 35%, while the expression of the U6 RBE(apt) did not affect p24 production. The suppression of HIV production from the HIV proviral clones by the CMV promoter constructs in the co-transfection assays may be explained by competition for transcription factors (TFs) between HIV and CMV promoters. This observation points to the potential for misleading results in co-transfections involving CMV constructs and HIV.

Secretory leukocyte protease inhibitor (SLPI): oxidation of SLPI does not explain its variable anti-HIV activity

Secretory leukocyte protease inhibitor (SLPI) has been proposed as a potential inhibitor of HIV-1 infection in human saliva. Although the ability of recombinant (r) SLPI to inhibit HIV-1 infection of macrophages and primary T-cells has been demonstrated by two independent laboratories, evidence to the contrary has also been reported. This study re-examines the anti-HIV effect of rSLPI and investigates the effects of repeated freeze-thawing and oxidation on the anti-HIV activity of rSLPI. rSLPI inhibited HIV-1BaL infection of human macrophages in a highly variable manner. HPLC and electrospray ionization mass spectrometry (ESI) analyses indicated that variability in our inhibition data could not be attributed to the degradation or oxidation of rSLPI. These results suggest that the variable anti-HIV effect of rSLPI may be due to differential expression of the cell-surface molecule(s) to which SLPI binds rather than to changes in the rSLPI molecule.

Anti-HIV activity of amphotericin B-cholesteryl sulfate colloidal dispersion in vitro

We examined whether the anti-HIV-1 activity of the polyene antibiotic Amphotericin B (AMB) is retained following incorporation into sterically stabilized 'Stealth' liposomes (L-AMB) with prolonged circulation in vivo, or cholesteryl sulfate colloidal dispersions (CD-AMB). The effects of the different preparations on acute infection of H9 cells with HIV-1IIIB, spreading of the virus from chronically infected H9/HTLV-IIIB cells to SupT1 cells, and HIV-1-induced syncytium formation were evaluated. Infection was monitored by p24 levels in culture supernatants. L-AMB did not affect HIV-1 infection. When present only during initial infection, AMB (3-20 microg/ml) reduced p24 levels by 70-80% after 7 and 10 days post-infection, while CD-AMB inhibited p24 production by approximately 30-40% at day 7 and 50-60% at day 10. The inhibitory effect of CD-AMB and AMB was enhanced by continuous treatment of acutely infected cells. The reduction of p24 production during continuous treatment was not due to cytotoxicity. During spreading of infection from infected to uninfected cells, AMB almost completely inhibited virus production while CD-AMB reduced both p24 production and the cytopathic effect in a dose-dependent manner. HIV-1 induced syncytium formation was slightly inhibited by AMB but not by CD-AMB. Because CD-AMB is considerably less cytotoxic than AMB, its ability to inhibit HIV infection in vivo needs to be evaluated further.

Liposome-mediated delivery of antiviral agents to human immunodeficiency virus-infected cells

Intracellular delivery of novel macromolecular drugs against human immunodeficiency virus type-1 (HIV-1), including antisense oligodeoxynucleotides, ribozymes and therapeutic genes, may be achieved by encapsulation in or association with certain types of liposomes. Liposomes may also protect these drugs against nucleases. Low-molecular-weight, charged antiviral drugs may also be delivered more efficiently via liposomes. Liposomes were targeted to HIV-1-infected cells via covalently coupled soluble CD4. An HIV-1 protease inhibitor encapsulated in conventional negatively charged multilamellar liposomes was about 10-fold more effective and had a lower EC90 than the free drug in inhibiting HIV-1 production in human monocyte-derived macrophages. The drug encapsulated in sterically stabilized liposomes was as effective as the free drug. The EC50 of the reverse transcriptase inhibitor 9-(2-phosphonylmethoxyethyl)adenine (PMEA) was reduced by an order of magnitude when delivered to HIV-1-infected macrophages in pH-sensitive liposomes. A 15-mer antisense oligodeoxynucleotide against the Rev response element was ineffective in free form against HIV-1 replication in macrophages, while delivery of the oligonucleotide in pH-sensitive liposomes inhibited virus replication. The oligodeoxynucleotide encapsulated in sterically stabilized pH-sensitive liposomes with prolonged circulation in vivo, which were recently developed in the laboratories of the authors, was also highly effective. A ribozyme complementary to HIV-1 5'-LTR delivered in pH-sensitive liposomes inhibited virus production by 90%, while the free ribozyme caused only a slight inhibition. Cationic liposome-mediated co-transfection of the HIV-regulated diphtheria toxin A fragment gene and a proviral HIV clone into HeLa cells completely inhibited virus production, while the frame-shifted mutant gene was ineffective. Co-transfection of the proviral genome and a gene encoding a Rev-binding aptamer into HeLa cells via transferrin-associated cationic liposomes inhibited virus production. These studies indicate that liposomes can be used to facilitate the intracellular delivery of certain anti-HIV agents and to enhance their therapeutic effects. These properties may be particularly advantageous in the development of novel macromolecular drugs, which may be necessary because of the emergence of virus strains resistant to the currently available drugs.

Receptor ligand-facilitated cationic liposome delivery of anti-HIV-1 Rev-binding aptamer and ribozyme DNAs

We examined whether HIV-1 gene expression could be inhibited by the anti-HIV Rev-binding aptamer [RBE(apt)], and whether the antiviral effect of the aptamer could be enhanced by a ribozyme directed against the HIV-1 env gene. Since cationic liposomes are relatively safe and non-immunogenic for in vivo gene delivery, we tested the effectiveness of the aptamer and ribozyme DNAs in HeLa cells, using Lipofectin reagent in a transient transfection assay. To increase the transfection efficiency, lipofectin was mixed with transferrin before subsequent addition of DNA. Co-transfection of HeLa cells with the RBE(apt) and the proviral HIV clone, HXBdeltaBgl, resulted in inhibition of virus production. Specific inhibition of viral p24 production following co-transfection of the RBE(apt) and HIV proviral DNAs was observed. These data provide strong support for the use of in vitro evolved ligands as potential anti-HIV agents. The addition of the anti-env ribozyme to the aptamer construct did not further enhance the antiviral activity, suggesting either that we had reached the limits of inhibition in this assay, or that the ribozyme was not able to access its target site with Rev bound to the RBE aptamer. The observed inhibition of p24 production could not be attributed to the non-specific toxicity of the transfection procedure, because no difference in viability was observed between the RBE(apt)- and the vector control-treated cells. All of the aptamer-ribozyme constructs as well as the RBE(apt) were similarly effective.

Delivery of an anti-HIV-1 ribozyme into HIV-infected cells via cationic liposomes

Cationic liposome-mediated intracellular delivery of a fluorescein-labeled chimeric DNA-RNA ribozyme targeted to the HIV-1 5' LTR was investigated, using THP-1, THP-1/HIV-1IIIB or HeLa/LAV cells. Different fluorescence patterns were observed when the cells were exposed to Lipofectamine, Lipofectin or DMRIE:DOPE (1:1) complexed to the ribozyme. With Lipofectamine intense cell-associated fluorescence was found. Incubation with Lipofectin resulted in less intense diffuse fluorescence, while with DMRIE an intense but sporadic fluorescence was observed. Differentiated THP-1/HIV-1IIIB cells were more susceptible to killing by liposome-ribozyme complexes than THP-1 cells. Under non-cytotoxic conditions (a 4-h treatment) complexes of 5, 10 or 15 microM Lipofectin or DOTAP:DOPE (1:1) and ribozyme, at lipid:ribozyme ratios of 8:1 or 4:1, did not affect p24 production in THP-1/HIV-1IIIB cells in spite of the intracellular accumulation of the ribozyme. A 24-h exposure of THP-1/HIV-1IIIB cells to 5 microM Lipofectin or DOTAP:DOPE (1:1) complexed with either the functional or a modified control ribozyme reduced virus production by approximately 30%. Thus, the antiviral effect of the liposome-complexed ribozyme was not sequence-specific. In contrast, the free ribozyme at a relatively high concentration inhibited virus production by 30%, while the control ribozyme was ineffective, indicating a sequence-specific effect. Both Lipofectin and DOTAP complexed with ribozyme were toxic at 10 and 15 microM after a 24-h treatment. A 4-h treatment of HeLa/LAV cells with Lipofectin at 5, 10 or 15 microM was not toxic to the cells, but also did not inhibit p24 production. In contrast, treatment of HeLa CD4+ cells immediately after infection with HIV-1IIIB at the same lipid concentrations and lipid:ribozyme ratios was cytotoxic. Our results indicate that the delivery of functional ribozyme into cells by cationic liposomes is an inefficient process and needs extensive improvement before it can be used in ex vivo and in vivo applications.

Platelet-activating factor mediates angiotensin II-induced proteinuria in isolated perfused rat kidney

Isolated kidney preparations (IPK) from male Sprague Dawley rats perfused at constant pressure were used to evaluate the effect of angiotensin II (AII) and platelet-activating factor (PAF) on renal function and urinary protein excretion. Compared with basal, intrarenal infusion of AII at 8 ng/min caused a progressive increase in protein excretion (11 +/- 6 versus 73 +/- 21 micrograms/min) in parallel with a decline in renal perfusate flow (RPF) (29 +/- 3 versus 18 +/- 3 ml/min). Addition to the perfusate of PAF at 50 nM final concentration also induced proteinuria (9 +/- 4 versus 55 +/- 14 micrograms/min) but did not change RPF (29 +/- 3 versus 30 +/- 3 ml/min). Preexposure of isolated kidneys to the PAF receptor antagonist WEB 2086 prevented the increase in urinary protein excretion induced by AII infusion (basal: 13 +/- 6; post-AII: 12 +/- 7 micrograms/min) but failed to prevent the vasoactive effect of AII (RPF, basal: 30 +/- 2; post-AII: 21 +/- 3 ml/min). In additional experiments, dexamethasone reduced the proteinuric effect of PAF remarkably. These results indicate that in isolated kidney preparation: (1) AII infusion induced proteinuria and decreased RPF; and (2) the effect of AII in enhancing urinary protein excretion was completely prevented by a specific PAF receptor antagonist, which, however, did not influence the AII-induced fall in RPF. It is suggested that PAF plays a major role in AII-induced changes in the permselective function of the glomerular capillary barrier.

Cationic liposome-mediated expression of HIV-regulated luciferase and diphtheria toxin a genes in HeLa cells infected with or expressing HIV

HIV-regulated expression of the diphtheria toxin A fragment gene (HIV-DT-A) is a potential gene therapy approach to AIDS. Since cationic liposomes are safe and non-immunogenic for in vivo gene delivery, we examined whether LipofectAMINE or DMRIE reagent could mediate the transfection of HIV-DT-A (pTHA43) or the HIV-regulated luciferase gene (pLUCA43) into HIV-infected or uninfected HeLa cells. pLUCA43 was expressed at a 10(3)-fold higher level in HeLa/LAV cells than in uninfected HeLa cells, while the extent of expression of RSV-regulated luciferase was the same in both cell lines. Co-transfection of HeLa cells with pTHA43 and the proviral HIV clone, HXB deltaBgl, resulted in complete inhibition of virus production. In contrast, the delivery of HIV-DT-A to chronically infected HeLa/LAV or HeLa/IIIB cells, or to HeLa CD4+ cells before infection, did not have a specific effect on virus production, since treatment of cells with control plasmids also reduced virus production. This reduction could be ascribed to cytotoxicity of the reagents. The efficiency of transfection, as measured by the percentage of cells expressing beta-gal, was approximately 5%. Thus, cationic liposome-mediated transfection was too inefficient to inhibit virus production when the DT-A was delivered by cationic liposomes to chronically- or de novo- infected cells. However, when both the virus and DT-A genes were delivered into the same cells by cationic liposomes, DT-A was very effective at inhibiting virus production. Our results indicate that the successful use of cationic liposomes for gene therapy will require the improvement of their transfection efficiency.

The anti-HIV-1 activity associated with saliva

This review summarizes the data on the anti-human immunodeficiency virus (HIV) activity associated with saliva and the possible routes of oral transmission of HIV. Saliva can be passed from an HIV-infected individual to an uninfected person via sexual or non-sexual activities. The relative risk of HIV transmission through saliva is a subject of continuing concern for dental practitioners. HIV-infected individuals frequently have oral lesions that can cause bleeding and release of the virus into the oral cavity. In addition, viral p24 and HIV-1 RNA were detected in tonsils and adenoids even in asymptomatic seropositive individuals. Nevertheless, the potential HIV-infectivity of saliva is low, although both infectious HIV-1 and HIV DNA have been detected in saliva. This observation has led to the suggestion that saliva may contain factors that inhibit HIV-1 infectivity. At least two anti-HIV activities have been partially characterized: (i) physical entrapment of HIV by high-molecular-weight molecules (e.g., mucins), and (ii) inhibition of viral infection by soluble proteins. Several studies have indicated that, of the salivary proteins evaluated, recombinant secretory leukocyte protease inhibitor (rSLPI) could inhibit HIV-1 infection in macrophages at physiological concentrations. The anti-HIV activity of the serine protease inhibitor rSLPI is most likely due to its interaction with a cell-surface molecule(s) other than the primary HIV-1 receptor, CD4, and may involve (i) inhibition of cell-surface serine protease(s), and/or (ii) interaction with other human-specific co-factors essential for viral entry.

Human immunodeficiency virus type-1 (HIV-1) infection increases the sensitivity of macrophages and THP-1 cells to cytotoxicity by cationic liposomes

Cationic liposomes may be valuable for the delivery of anti-sense oligonucleotides, ribozymes, and therapeutic genes into human immunodeficiency virus type 1 (HIV-1)-infected and uninfected cells. We evaluated the toxicity of three cationic liposomal preparations, Lipofectamine, Lipofectin, and 1, 2-dimyristyloxypropyl-3-dimethyl-hydroxyethyl ammonium bromide (DMRIE) reagent, to HIV-infected and uninfected cells. Monocyte/macrophages were infected with HIV-1BaL and treated with liposomes in medium containing 20% fetal bovine serum (FBS) for 4 h or 24 h at 37 degree C. Uninfected monocytic THP-1 cells and chronically infected THP-1/HIV-1IIIB cells were treated with phorbol 12-myristate 13-acetate (PMA) and exposed to liposomes in the presence of 10% FBS. Toxicity was evaluated by the Alamar Blue assay and viral p24 production. The toxic effect of cationic liposomes was very limited with uninfected cells, although concentrations of liposomes that were not toxic within a few days of treatment could cause toxicity at later times. In HIV-1BaL-infected macrophages, Lipofectamine (up to 8 microM) and Lipofectin (up to 40 microM) were not toxic after a 4-h treatment, while DMRIE reagent at 40 microM was toxic. While a 4-h treatment of THP-1/HIV-1IIIB cells with the cationic liposomes was not toxic, even up to 14 days post-treatment, all three cationic liposomes were toxic to cells at the highest concentration tested after a 24-h treatment. Similar results were obtained with the Alamar Blue assay, Trypan Blue exclusion and a method that enumerates nuclei. Infected cells with relatively high overall viability could be impaired in their ability to produce virions, indicating that virus production appears to be more sensitive to treatment with the cationic liposomes than cell viability. Our results indicate that HIV-infected cells are more susceptible than uninfected cells to killing by cationic liposomes. The molecular basis of this differential effect is unknown; it is proposed that alterations in cellular membranes during virus budding cause enhanced interactions between cationic liposomes and cellular membranes.

The stoichiometry of the cytochrome P-450-catalyzed metabolism of methoxyflurane and benzphetamine in the presence and absence of cytochrome b5

The complete stoichiometry of the metabolism of the cytochrome b5 (cyt b5)-requiring substrate, methoxyflurane, by purified cytochrome P-450 2B4 was compared to that of another substrate, benzphetamine, which does not require cyt b5 for its metabolism. Cyt b5 invariably improved the efficiency of product formation. That is, in the presence of cyt b5 a greater percentage of the reducing equivalents from NADPH were utilized to generate substrate metabolites, primarily at the expense of the side product, superoxide. With methoxyflurane, cyt b5 addition always resulted in an increased rate of product formation, while with benzphetamine the rate of product formation remained unchanged, increased or decreased. The apparently contradictory observations of increased reaction efficiency but decrease in total product formation for benzphetamine can be explained by a second effect of cyt b5. Under some experimental conditions cyt b5 inhibits total NADPH consumption. Whether stimulation, inhibition, or no change in product formation is observed in the presence of cyt b5 depends on the net effect of the stimulatory and inhibitory effects of cyt b5. When total NADPH consumption is inhibited by cyt b5, the rapidly metabolized, highly coupled (approximately equal to 50%) substrate, benzphetamine, undergoes a net decrease in metabolism not counterbalanced by the increase in the efficiency (2-20%) of the reaction. In contrast, in the presence of the slowly metabolized, poorly coupled (approximately equal to 0.5-3%) substrate, methoxyflurane, inhibition of total NADPH consumption by cyt b5 was never sufficient to overcome the stimulation of product formation due to an increase in efficiency of the reaction.

Differential effects of a hydrophobic tripeptide on human immunodeficiency virus type 1 (HIV-1)-induced syncytium formation and viral infectivity

The synthetic hydrophobic peptide, Z-D-Phe-L-Phe-Gly, was shown previously to inhibit the infectivity of paramyxoviruses and the fusion of Sendai virus with liposomes. We examined the ability of this peptide to inhibit HIV-1 infectivity in A3.01, Sup-T1, and H9 cells and syncytium formation between these cells and chronically infected H9 cells. Although the peptide inhibited syncytium formation in a dose-dependent manner, its effect on virus infectivity was very limited. Our results suggest that the mechanisms of interaction of the HIV-1 envelope glycoprotein gp120/gp41 with the target cell membrane leading to membrane fusion may be different in cell-cell and virus-cell fusion.

A monoclonal antibody to the gp120-CD4 complex has differential effect on HIV-induced syncytium formation and viral infectivity

A murine monoclonal antibody (MAb F-91-55) raised against the complex of soluble CD4 and human immunodeficiency virus type 1 (HIV-1) gp120 had previously been found to inhibit syncytium formation without inhibiting the interaction of CD4 with gp120, and its binding site was localized within the first two domains (D1/D2) of CD4. We investigated whether this antibody inhibited the infectivity of HIV-1 in the CD4+ T cell lines A3.01, Sup-T1 and H9. We also examined the effect of the antibody on syncytium formation between these cells and chronically infected H9 cells. Syncytium formation was found to depend critically on the incubation medium used. The effect of the MAb on HIV-1 infectivity was very limited with A3.01 and Sup-T1 cells, although it inhibited syncytium formation between A3.01 or Sup-T1 and chronically infected H9 cells. In contrast, the MAb inhibited significantly the infectivity of HIV-1 in H9 cells, but it also inhibited syncytium formation between H9 and chronically infected H9 cells to a greater extent than in the case of the other cell lines. Our results indicate that cellular systems used for syncytium assays differ in their susceptibility to inhibitory antibodies. In the A3.01 and Sup-T1 cell systems, the differences in the ability of the MAb to block viral entry or syncytium formation raise the possibility that the mechanisms of interaction of gp120/gp41 with cell membrane CD4 may be different in cell-cell and virus-cell membrane fusion.

Liposome targeting to human immunodeficiency virus type 1-infected cells via recombinant soluble CD4 and CD4 immunoadhesin (CD4-IgG)

HIV-infected cells producing virions express the viral envelope glycoprotein gp120/gp41 on their surface. We examined whether liposomes coupled to recombinant soluble CD4 (sCD4, the ectodomain of CD4 which binds gp120 with high affinity) could specifically bind to HIV-infected cells. sCD4 was chemically coupled by 2 different methods to liposomes containing rhodamine-phosphatidylethanolamine in their membrane as a fluorescent marker. In one method, sCD4 was thiolated with N-succinimidyl acetylthioacetate (SATA) and coupled to liposomes via a maleimide-derivatised phospholipid. In the other method, the oligosaccharides on sCD4 were coupled to a sulfhydryl-derivatised phospholipid, utilizing the bifunctional reagent, 4-(4-N-maleimidophenyl)butyric acid hydrazide (MPBH). The association of the liposomes with HIV-1-infected or uninfected cells was examined by flow cytometry. CD4-coupled liposomes associated specifically to chronically infected H9/HTLV-IIIB cells, but not to uninfected H9 cells. CD4-coupled liposomes also associated specifically with monocytic THP-1 cells chronically infected with HIV-1 (THP-1/HIV-1IIIB). Control liposomes without coupled CD4 did not associate significantly with any of the cells, while free sCD4 could competitively inhibit the association of the CD4-coupled liposomes with the infected cells. The chimeric molecule CD4-immunoadhesin (CD4-IgG) could also be used as a ligand to target liposomes with covalently coupled Protein A (which binds the Fc region of the CD4-IgG) to H9/HTLV-IIIB cells. The CD4-liposomes inhibited the infectivity of HIV-1 in A3.01 cells, and also bound rgp120. Our results suggest that liposomes containing antiviral or cytotoxic agents may be targeted specifically to HIV-infected cells.

Long-term noncytopathic productive infection of the human monocytic leukemia cell line THP-1 by human immunodeficiency virus type 1 (HIV-1IIIB)

A long-term, noncytopathic, productive infection of the monocytic leukemia cell line THP-1 with human immunodeficiency virus type 1 (HIV-1IIIB) was established. Both infected cells (THP-1/HIV-1IIIB) growing in suspension and uninfected, phorbol 12-myristate 13-acetate (PMA)-treated THP-1 cells, which are adherent, showed ultrastructural characteristics of differentiated cells. PMA-treated THP-1 cells could not be productively infected with HIV-1IIIB. THP-1/HIV-1IIIB cells produced virions mainly by budding at the plasma membrane. These cells retained the ability to differentiate into macrophage-like cells, capable of releasing the virus for extended periods of time (e.g., 40 days). PMA-mediated differentiation of THP-1/HIV-1IIIB cells modified the pattern of virus localization. Immediately after PMA treatment mature viral particles were primarily observed extracellularly. After 21 days in culture, however, the virions accumulated in intracellular vacuoles. THP-1/HIV-1IIIB cells may be used as a useful model system for HIV-infected macrophages.

Enhancement of human immunodeficiency virus type 1 infection by cationic liposomes: the role of CD4, serum and liposome-cell interactions

We have reported previously the enhancement of the infectivity of human immunodeficiency virus type 1 (HIV-1) by liposomes composed of the cationic lipid N-[2,3-(dioleyloxy) propyl]-N,N,N-trimethylammonium chloride (DOTMA). To determine the mechanism by which this process occurs, we have investigated the role of CD4, serum concentration and liposome-cell interactions in the DOTMA-mediated stimulation of HIV-1 infection of A3.01 cells. Serum alone significantly inhibited the binding and infectivity of HIV-1, but DOTMA-mediated enhancement of infectivity was more pronounced in the presence of serum than in its absence. HIV-1 binding to cells was increased in the presence of DOTMA liposomes, DEAE-dextran and polybrene, all of which also enhanced infectivity to a similar extent at comparable concentrations. Fluorescence dequenching measurements indicated that DOTMA liposomes fused with HIV-1, but not with cell membranes, in the presence of serum. The enhancing effect of DOTMA liposomes on HIV-1 infectivity was CD4-dependent, and appeared to involve virus-liposome fusion and liposome binding to the cell surface. DOTMA liposomes did not mediate infection of the CD4-K562 and Raji cell lines.

Liposomes modulate human immunodeficiency virus infectivity

We have investigated the effects of the fusion of liposomes with human immunodeficiency virus type 1 (HIV-1LVA) on the ability of the virus to infect CD4+ and CD4- cells. Fluorescence dequenching measurements indicated that HIV-1 fuses with liposomes composed of either cardiolipin (CL) or N-[2,3-(dioleyloxy) propyl]-N,N,N-trimethyl ammonium chloride (DOTMA) but not appreciably with dioleoylphosphatidylcholine (DOPC) liposomes. Pre-incubation of HIV-1 with DOTMA liposomes enhanced virus production (measured by p24 gag antigen production in the culture medium and in situ) in CD4+ A3.01 and H9 cells in a concentration-dependent manner, but did not mediate the infection of the CD4- cell line, K562. Preincubation of HIV-1 with between 10 and 30 microM-DOTMA liposomes, and subsequent incubation with A3.01 cells, resulted in the production of about 30-fold greater levels of virus than controls. The presence of DOTMA liposomes during the incubation of A3.01 cells with HIV-1 enhanced the infectivity of the virus up to 90-fold compared to controls. Conversely, preincubation of HIV-1 with CL liposomes inhibited infection of A3.01 cells, dependent on the concentration of liposomes; DOPC liposomes did not alter the infectivity of the virus under any of the incubation conditions. Our results thus indicate that fusion of HIV-1 with liposomes alters the ability of the virus to infect its target cells.