Sex and Gender in Lung Diseases and Sleep Disorders: A State-of-the-Art Review: Part 2

There is now ample evidence that differences in sex and gender contribute to the incidence, susceptibility, presentation, diagnosis, and clinical course of many lung diseases. Some conditions are more prevalent in women, such as pulmonary arterial hypertension and sarcoidosis. Some life stages-such as pregnancy-are unique to women and can affect the onset and course of lung disease. Clinical presentation may differ as well, such as the higher number of exacerbations experienced by women with cystic fibrosis (CF), more fatigue in women with sarcoidosis, and more difficulty in achieving smoking cessation. Outcomes such as mortality may be different as well, as indicated by the higher mortality in women with CF. In addition, response to therapy and medication safety may also differ by sex, and yet, pharmacogenomic factors are often not adequately addressed in clinical trials. Various aspects of lung/sleep biology and pathobiology are impacted by female sex and female reproductive transitions. Differential gene expression or organ development can be impacted by these biological differences. Understanding these differences is the first step in moving toward precision medicine for all patients. This article is the second part of a state-of-the-art review of specific effects of sex and gender focused on epidemiology, disease presentation, risk factors, and management of selected lung diseases. We review the more recent literature and focus on guidelines incorporating sex and gender differences in pulmonary hypertension, CF and non-CF bronchiectasis, sarcoidosis, restless legs syndrome and insomnia, and critical illness. We also provide a summary of the effects of pregnancy on lung diseases and discuss the impact of sex and gender on tobacco use and treatment of nicotine use disorder.

Sex and Gender in Lung Disease and Sleep Disorders: A State-of-the-Art Review

The terms sex and gender often are used interchangeably, but have specific meaning when it comes to their effects on lung disease. Ample evidence is now available that sex and gender affect the incidence, susceptibility, presentation, diagnosis, and severity of many lung diseases. Some conditions are more prevalent in women, such as asthma. Other conditions are seen almost exclusively in women, like lymphangioleiomyomatosis. Some life stages-such as pregnancy-are unique to women and can affect the onset and course of lung disease. Clinical presentation may differ as well, such as higher number of exacerbations experienced by women with COPD and greater cardiovascular morbidity in women with sleep-disordered breathing. In addition, response to therapy and medication safety may also differ by sex, and yet, pharmacogenomic factors often are not addressed adequately in clinical trials. Various aspects of lung and sleep biology and pathobiology are impacted by female sex and female reproductive transitions. Differential gene expression or organ development can be impacted by these biological differences. Understanding these differences is the first step in moving toward precision medicine for women. This article is a state-of-the-art review of specific effects of sex and gender focused on epidemiology, disease presentation, risk factors, and management of lung diseases. Pathobiological mechanisms explaining sex differences in these diseases are beyond the scope of this article. We review the literature and focus on recent guidelines about using sex and gender in research. We also review sex and gender differences in lung diseases.

Midodrine in Liver Cirrhosis With Ascites: A Systematic Review and Meta-Analysis

Ascites is the most common complication of liver cirrhosis. Midodrine is a vasoconstrictor that improves splanchnic and systemic hemodynamics, reduces ascites, and improves clinical outcomes. Here, we aimed to examine the role of midodrine in cirrhosis-related ascites.

Scopus, Embase, PubMed, and PubMed Central databases were searched for relevant randomized controlled trials comparing midodrine with other interventions in patients with cirrhotic ascites on November 25, 2020, using appropriate keywords like “midodrine”, “ascitic cirrhosis”, “peritoneal paracentesis” and suitable Boolean operators. Odds ratio (OR) and mean difference (MD) were used to analyze pool data as appropriate with a 95% confident interval (CI).

A total of 14 studies were included in our analysis including 1199 patients. The addition of midodrine resulted in statistically significant improvement in mean arterial pressure (MAP) (MD, 3.95 mmHg; 95% CI, 1.53-6.36) and MELD (Model for End-Stage Liver Disease) score (MD, -1.27; 95% CI, -2.49 to -0.04) compared to standard medical treatment (SMT). There was also a significant improvement in plasma renin activity and plasma aldosterone concentration. However, there was no significant improvement in mortality or serum creatinine compared to SMT. In addition, there was no statistically significant improvement in MAP, plasma renin activity, plasma aldosterone concentration, MELD score, overall mortality, and paracentesis-induced circulatory dysfunction comparing midodrine with albumin.

Midodrine alone leads to significant improvement in various clinical parameters in patients with cirrhotic ascites compared to standard medical care. At the same time, it was found to be non-inferior to albumin. Therefore, further well-designed studies need to be carried out on midodrine in addition to albumin for optimal clinical benefits among patients with ascites due to cirrhosis.

Vasopressin versus norepinephrine as the first-line vasopressor in septic shock: A systematic review and meta-analysis

Background and Aim

Norepinephrine is currently the first-line vasopressor for septic shock. We conducted this meta-analysis to examine the outcomes of adult patients with septic shock who received vasopressin instead of norepinephrine.

Methods

We selected studies in adults with septic shock that compared the outcomes of patients treated with vasopressin versus norepinephrine. Cochrane ROB 2.0 and the Joanna Briggs Institute quality assessment tools were used to assess the risk of bias in RCTs and observational studies. Meta-analysis was conducted using RevMan 5.4.

Results

Eight studies were included in this meta-analysis. There were no significant differences in 28-day mortality rates (OR, 1.07; CI, 0.80-1.44) and intensive care unit (ICU) mortality (OR, 0.74; CI, 0.21-2.67) between the two groups. Similarly, length of ICU stay, length of hospital stay, mean arterial pressure at 24 h, urine output at 24 h, and serious adverse events also did not differ significantly. However, the odds of renal replacement therapy (RRT) requirement in the vasopressin group were substantially lower than in the norepinephrine group (OR, 0.68; CI, 0.47-0.98).

Conclusion

There were no differences in mortality, duration of hospitalization, and adverse effects in adults with septic shock across the two groups. However, the patients treated with vasopressin had lower chances of requiring RRT.

Relevance for Patients

Vasopressin use as the first-line vasopressor in septic shock showed a significant reduction in RRT, though there were no significant differences in terms of mortality and other adverse events. Therefore, vasopressin can be considered as a first-line vasopressor in septic shock patients with other risk factors which may contribute to renal failure requiring RRT.

eARDS: A multi-center validation of an interpretable machine learning algorithm of early onset Acute Respiratory Distress Syndrome (ARDS) among critically ill adults with COVID-19

We present an interpretable machine learning algorithm called ‘eARDS’ for predicting ARDS in an ICU population comprising COVID-19 patients, up to 12-hours before satisfying the Berlin clinical criteria. The analysis was conducted on data collected from the Intensive care units (ICU) at Emory Healthcare, Atlanta, GA and University of Tennessee Health Science Center, Memphis, TN and the Cerner^® Health Facts Deidentified Database, a multi-site COVID-19 EMR database. The participants in the analysis consisted of adults over 18 years of age. Clinical data from 35,804 patients who developed ARDS and controls were used to generate predictive models that identify risk for ARDS onset up to 12-hours before satisfying the Berlin criteria. We identified salient features from the electronic medical record that predicted respiratory failure among this population. The machine learning algorithm which provided the best performance exhibited AUROC of 0.89 (95% CI = 0.88–0.90), sensitivity of 0.77 (95% CI = 0.75–0.78), specificity 0.85 (95% CI = 085–0.86). Validation performance across two separate health systems (comprising 899 COVID-19 patients) exhibited AUROC of 0.82 (0.81–0.83) and 0.89 (0.87, 0.90). Important features for prediction of ARDS included minimum oxygen saturation (SpO₂), standard deviation of the systolic blood pressure (SBP), O₂ flow, and maximum respiratory rate over an observational window of 16-hours. Analyzing the performance of the model across various cohorts indicates that the model performed best among a younger age group (18–40) (AUROC = 0.93 [0.92–0.94]), compared to an older age group (80+) (AUROC = 0.81 [0.81–0.82]). The model performance was comparable on both male and female groups, but performed significantly better on the severe ARDS group compared to the mild and moderate groups. The eARDS system demonstrated robust performance for predicting COVID19 patients who developed ARDS at least 12-hours before the Berlin clinical criteria, across two independent health systems.

Outcomes of critically ill solid organ transplant patients with COVID-19 in the United States

National data on patient characteristics, treatment, and outcomes of critically ill coronavirus disease 2019 (COVID-19) solid organ transplant (SOT) patients are limited. We analyzed data from a multicenter cohort study of adults with laboratory-confirmed COVID-19 admitted to intensive care units (ICUs) at 68 hospitals across the United States from March 4 to May 8, 2020. From 4153 patients, we created a propensity score matched cohort of 386 patients, including 98 SOT patients and 288 non-SOT patients. We used a binomial generalized linear model (log-binomial model) to examine the association of SOT status with death and other clinical outcomes. Among the 386 patients, the median age was 60 years, 72% were male, and 41% were black. Death within 28 days of ICU admission was similar in SOT and non-SOT patients (40% and 43%, respectively; relative risk [RR] 0.92; 95% confidence interval [CI]: 0.70-1.22). Other outcomes and requirement for organ support including receipt of mechanical ventilation, development of acute respiratory distress syndrome, and receipt of vasopressors were also similar between groups. There was a trend toward higher risk of acute kidney injury requiring renal replacement therapy in SOT vs. non-SOT patients (37% vs. 27%; RR [95% CI]: 1.34 [0.97-1.85]). Death and organ support requirement were similar between SOT and non-SOT critically ill patients with COVID-19.

Prognostication via early computed tomography head in patients treated with targeted temperature management after cardiac arrest

BACKGROUND

We evaluated computed tomography head (CTH) imaging obtained prior to targeted temperature management (TTM) in patients after cardiac arrest, and its role in prognostication.

METHODS

In this retrospective cohort study in a tertiary-care hospital, 341 adults presenting with out-of-hospital cardiac arrest received a CTH prior to TTM. Associations between outcomes and neuroimaging variables were evaluated with Chi-square analysis for significant associations that yielded a composite neuroimaging score-Tennessee Early Neuroimaging Score (TENS). Univariable and multivariable logistic regression analysis including TENS as an independent variable and the four outcome dependent variables were analyzed.

RESULTS

Four of the neuroimaging variables-sulcal effacement, partial gray-white matter effacement, total gray-white matter effacement, deep nuclei effacement-had significant associations with each of the four outcome variables and yielded TENS. In multivariable logistic regression models adjusted for potential confounders, TENS was associated with poor discharge CPC (OR 2.15, 95%CI 1.16-3.98, p = .015), poor disposition (OR 2.62, 95%CI 1.37-5.02, p = .004), in-hospital mortality (OR 1.99, 95%CI 1.09-3.62, p = .024), and ICU mortality (OR 1.89, 95%CI 1.12-3.20, p = .018).

CONCLUSION

Imaging prior to TTM may help identify post-cardiac arrest patients with severe anoxic brain injury and poor outcomes.

Endobronchial Lesions in Patients Presenting with Hemoptysis

OBJECTIVES

The aim of this study was to determine the incidence of endobronchial lesions in patients presenting with hemoptysis. We also aimed to characterize features that would predict whether bronchoscopy would be useful.

METHODS

A retrospective chart review was conducted on 185 consecutive patients who presented with hemoptysis from January 1, 2006 to December 31, 2015 at Methodist Le Bonheur Healthcare-affiliated hospitals in Memphis, Tennessee. Data collection included demographic information, description of hemoptysis, imaging results, bronchoscopy results, and the final diagnosis.

RESULTS

A total of 185 patients presented with hemoptysis during our study period. Of these, 14 patients were excluded because of age (younger than 18 years) and incomplete data (inadequate information about the procedure performed, lack of imaging studies, incorrect International Classification of Diseases, Ninth Revision coding). The final analysis was performed in 171 patients; 87 underwent bronchoscopy either to determine etiology or to aid in management. Most patients (73%) had mild hemoptysis, with approximately half of the patients having hemoptysis for ≤1 day. Of 87 people who underwent bronchoscopy, 12 (13.8%) were found to have endobronchial lesions, and 35 (51.7%) patients were found to have either active bleeding or had fresh blood in their airway during bronchoscopy. Final diagnoses included pneumonia/bronchitis in 30 (18.9%) patients, malignancy in 24 (15.1 %), and anticoagulation toxicity in 23 (14.5%) patients.

CONCLUSIONS

Bronchoscopy should be strongly considered in patients presenting with hemoptysis, especially if it is frank blood, of >1 week's duration, or both, because the information obtained can be vital for management. This appears to hold true even for patients who have no abnormalities seen on computed tomography chest imaging upon initial workup.

Atrio-Esophageal Fistula: A Case Series and Literature Review

Case series

Patient: Male, 72 • Male, 29 • Male, 75

Final Diagnosis: Atrio-esophageal fistula

Symptoms: Altered mental state • chest pain • fever • melena

Medication: —

Clinical Procedure: —

Specialty: Critical Care Medicine

Role of Transbronchial Needle Aspiration (Conventional and EBUS Guided) in the Diagnosis of Histoplasmosis in Patients Presenting with Mediastinal Lymphadenopathy

OBJECTIVES

The superior performance of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in the diagnosis and staging of malignancy has been demonstrated, with some investigators suggesting the same for sarcoidosis. The role of EBUS-TBNA in the diagnosis of histoplasmosis is not clear, however. In this study we estimate the diagnostic yield of conventional TBNA (cTBNA) and EBUS-TBNA for the diagnosis of histoplasmosis in patients with mediastinal lymphadenopathy.

METHODS

Retrospective chart review was conducted on 452 consecutive patients who underwent cTBNA or EBUS-TBNA for mediastinal lymphadenopathy from January 1, 2005 to December 31, 2014 at Methodist Le Bonheur Healthcare-affiliated hospitals in Memphis, Tennessee. Data collection included demographic information, reason for the procedure, size of the lymph nodes, procedures performed, and the final diagnosis.

RESULTS

Among 452 cases reviewed, 146 underwent cTBNA and 306 underwent EBUS-TBNA. Final diagnoses include malignancy (41.5%), sarcoidosis (11.2%), and histoplasmosis (8.1%). Among 146 patients who underwent cTBNA, a final diagnosis was obtained by this modality in 58 patients (39.7%). The diagnostic rate for cTBNA for malignancy was 68% (40/59), 30% (4/13) for sarcoidosis, and 43% (6/14) for histoplasmosis. In 306 patients who underwent EBUS-TBNA, 188 had a final diagnosis (61.4%) obtained by this modality. For EBUS-TBNA, the diagnostic rates were 79.5% (101/127) for malignancy, 74% (28/38) for sarcoidosis, and 78% (18/23) for histoplasmosis.

CONCLUSIONS

EBUS-TBNA had a higher yield than cTBNA for the diagnosis of histoplasmosis. Clinicians practicing in areas with a high prevalence of histoplasmosis and sarcoidosis should use EBUS-TBNA, whenever available, for this reason.

Chronic Granulomatous Disease Presenting as Aspergillus Fumigatus Pneumonia in a Previously Healthy Young Woman

BACKGROUND Chronic Granulomatous Disease (CGD) is a rare immunodeficiency disease caused by a genetic defect in the NADPH (nicotinamide adenine dinucleotide phosphate) oxidase enzyme, resulting in increased susceptibility to bacterial and fungal infections. The inheritance can be X-linked or autosomal recessive. Patients usually present with repeated infections early in life. We present an unusual case of a 23-year-old patient diagnosed with CGD. CASE REPORT A 23-year-old white woman with no previous history of recurrent infections presented with complaints of fever, shortness of breath, and diffuse myalgia. She had been treated twice for similar complaints recently, but without resolution. She was febrile, tachypneic, tachycardic, and hypoxic at presentation. Physical examination revealed diffuse inspiratory rales. Laboratory results showed leukocytosis. Her initial chest X-ray and CT chest showed reticular nodular interstitial lung disease pattern. Despite being on broad-spectrum antibiotics for 5 days, she continued to require supplemental oxygen and continued to be tachypneic, with minimal activity. Initial diagnostic tests, including bronchoscopy with biopsy and lavage, did not reveal a diagnosis. She then underwent a video-assisted thoracoscopic surgery (VATS) lung biopsy. The biopsy slides showed suppurative granulomatous inflammation affecting greater than 50% of the parenchymal lung surface. Fungal hyphae consistent with Aspergillus were present in those granulomas. A diagnosis of CGD was made and she was started on Voriconazole. She improved with treatment. Her neutrophil burst test showed negative burst on stimulation, indicating phagocytic dysfunction consistent with CGD. Autosomal recessive CGD was confirmed by genetic testing. CONCLUSIONS CGD can present in adulthood without any previous symptoms and signs. Clinicians should consider this disease in patients presenting with recurrent or non-resolving infections. Timely treatment and prophylaxis has been shown to reduce serious infections as well as mortality in these patients.

Therapeutic plasmapheresis for hypertriglyceridemia-associated acute pancreatitis: case series and review of the literature

BACKGROUND

Severe hypertriglyceridemia (HTG) is the third leading cause of acute pancreatitis (AP) in the United States. The current standard of care includes management of HTG using pharmacological therapy. More recently, plasmapheresis has been proposed as a therapeutic tool for decreasing triglyceride (TG) levels, especially in critically ill patients. Few studies are available to ascertain overall benefits of plasmapheresis over traditional management.

OBJECTIVE

To analyze the outcomes of patients treated with plasmapheresis for severe HTG-associated pancreatitis.

METHODS

We conducted a retrospective chart review of three patients with severe HTG- associated (TGs greater than 1000 mg/dl; 11.29 mmol/l) AP at the Methodist University Hospital. All the patients underwent plasmapheresis as part of their treatment.

RESULTS

The average TG level before plasmapheresis was 3532 mg/dl (range: 2524-4562 mg/dl; 39.9 mmol/l; range: 28.5-51.6 mmol/l). All patients made a full recovery, with a significant improvement in TG levels after plasmapheresis. The mean number of sessions was 1.3 (range 1-2), and mean TG level after plasmapheresis was 1051 mg/dl (range: 509-1771 mg/dl; 11.9 mmol/l; range: 5.8-20 mmol/l). After the first session, the average reduction of TG level was 2481 mg/dl (range 753-3750 mg/dl; 28 mmol/l; range: 8.5-42.4 mmol/l) or approximately 70%. None of the patients developed complications related to plasmapheresis.

CONCLUSIONS

Plasmapheresis can be an effective and rapid treatment option in patients with severe HTG and complications. However, further research, including randomized controlled studies, is necessary.

Pembrolizumab-induced myasthenia gravis: A fatal case report

Purpose Pembrolizumab, a monoclonal antibody which inhibits the programmed cell death 1 receptor, has been shown to efficaciously enhance pre-existing immune responses to malignancies. However, safety concerns must also be considered as pembrolizumab use has been associated with several life-threatening immune-related adverse events (irAEs). We report a fatal case of pembrolizumab-induced myasthenia gravis in a patient with no prior myasthenia gravis history. Case report A 63-year-old male presented with right eyelid drooping, puffiness, blurred vision, and shortness of breath two weeks after an initial infusion of pembrolizumab. He was subsequently diagnosed with new onset acetylcholine-receptor positive myasthenia gravis. Despite aggressive treatment with corticosteroids, pyridostigmine, intravenous immunoglobulin, and plasmapheresis, the patient clinically deteriorated and ultimately expired from acute respiratory failure after a 12-day hospitalization. Discussion Current package labeling for pembrolizumab warns against various irAEs associated with its use including pneumonitis, colitis, and endocrinopathies. To date, only one case of new onset myasthenia gravis and two case reports of myasthenia gravis exacerbation have been identified. This case further highlights the mortality risk associated with development of irAEs. Conclusion While rare, evidence for the development of MG associated with pembrolizumab is growing. Prompt recognition of symptoms and discontinuation of pembrolizumab is necessary to help improve prognosis.

Metastatic Squamous Cell Carcinoma of the Pleura: A Rare Complication of Hidradenitis Suppurativa

Patient: Male, 46

Final Diagnosis: Metastatic squamous cell carcinoma

Symptoms: Short of breath

Medication: —

Clinical Procedure: Pleural biopsy

Specialty: Oncology

Concurrent Myelomatous Pleural Effusion and Extramedullary Mediastinal Involvement as an Initial Manifestation of Multiple Myeloma

BACKGROUND Myelomatous pleural effusion (MPE) is a rare occurrence in patients with multiple myeloma (MM). Fewer than 20 cases of MPE have been reported as an initial manifestation of MM. Extramedullary plasmacytoma (EMP) occurs in fewer than 5% patients with MM, and mediastinal EMP is even rarer, with only about 80 cases reported in the literature. We present a case study involving a patient with concurrent MPE and mediastinal EMP as an initial manifestation of MM. CASE REPORT The patient was a 74-year-old nonsmoking female with a 3-month history of exertional dyspnea and back pain. On exam, the patient was afebrile (temperature 37.2°C), blood pressure was 160/74 mm Hg, heart rate was 92 bpm, respiratory rate was 22/min, and oxygen saturation was 87% on room air. Patient was in mild distress and had decreased breath sounds over right lung fields about halfway up with dullness to percussion. Computed tomography of the chest showed a moderate-sized right pleural effusion and an anterior mediastinal mass. Thoracentesis showed a lymphocyte-predominant exudate. Cytology showed numerous plasma cells including immature forms. Stains for CD138 were positive, confirming plasma cell origin of cells. The anterior mediastinal mass was also biopsied and showed diffuse infiltrate of lymphocytes with plasma cell features that were also positive for CD138. Systemic protein electrophoresis showed a monoclonal immunoglobulin G kappa spike, and bone marrow biopsy was consistent with MM. CONCLUSIONS MPE and EMP are extremely rare manifestations in MM. In addition, it is extremely rare for these to be the presenting features of MM. We report concurrently occurring MPE and EMP in a patient as her initial manifestation of MM.

Pleural Small Cell Lung Carcinoma: An Unusual Culprit in Pleural Effusion

Patient: Male, 77

Final Diagnosis: Pleural small cell carcinoma

Symptoms: Chest pain • shortness of breath

Medication: —

Clinical Procedure: Thoracocentesis

Specialty: Pulmonology

Solitary Fibrous Tumor of the Pleura: A Rare Cause of Pleural Mass

BACKGROUND

A solitary fibrous tumor of the pleura is a rare but usually benign mesenchymal tumor arising from the pleura. Patients are often asymptomatic, resulting in the majority of tumors being detected incidentally on chest imaging. We present a case of a large solitary pleural tumor and review the typical radiographic and pathologic findings associated with this finding.

CASE REPORT

A 63-year-old white man with chronic obstructive pulmonary disease (COPD) was found to have a large pleural mass on chest radiography during a pre-operative assessment. The tumor was biopsied and findings were consistent with solitary fibrous tumor of the pleura.

CONCLUSIONS

SFTPs are generally considered benign tumors although there is a risk of malignant transformation and recurrence. Imaging studies play an important role in identifying the tumor and planes of resection, and histologic diagnosis is critical in differentiating SFTP from other type of pleural masses. Surgical resection is main therapy of choice.

Wait!!! No Steroids for this Asthma…

Patient: Female, 31

Final Diagnosis: Hyperinfection syndrome due to Strongyloides stercoralis

Symptoms: Abdominal pain • shortness of breath

Medication: Prednisone

Clinical Procedure: Bronchoscopy with BAL

Specialty: Pulmonology

Synthesis, characterization and antiproliferative activity of 1,2-naphthoquinone and its derivatives

In the present study substituted 1,2-naphthoquinones were synthesized, purified and characterized by spectroscopic studies (UV, FT-IR, ¹H NMR, ¹³ C NMR and elemental analysis). These compounds were evaluated for cytotoxicity against a panel of human cancer cell lines (Hep-G₂ for liver sarcoma, MG-63 for osteosarcoma and MCF-7 for human breast cancer). The cells were dosed with these ortho-naphthoquinone derivatives at varying concentrations, and cell viability was measured by a 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay with doxorubicin as positive control. Significant anticancer activities were observed in vitro for some members of the series, and compounds 1,2-naphthoquinone 2-thiosemicarbazone, 1,2-naphthoquinone-2-semicarbazone, 4-amino-1,2-naphthoquinone 2-thiosemicarbazone and 4-amino-1,2-naphthoquinone-2-semicarbazone are active cytotoxic agents against different cancer cell lines with IC₅₀ values in the range of 5.73-17.67 μM. The obtained data suggested that better anticancer activity was linked with introduction of thiosemicarbazone and semicarbazone moiety in 1,2-naphthoquinone ring system. Outcomes of experimentation also reveal that incorporation of amino group in 1,2-naphthoquinone moiety contributes positively for cytotoxic action of compounds. Docking experiments showed a good correlation between their calculated interaction energies with the topoisomerase-II and the observed IC₅₀ values of all these compounds.

Midlife predictors of Alzheimer's disease

Factors contributing to increased risk for Alzheimer's disease (AD) include age, sex, genes, and family history of AD. Several risk factors for AD are endogenous; however, accumulating evidence implicates modifiable risk factors in the pathogenesis of AD. Although the continued task of identifying new genes will be critical to learning more about the disease, several research findings suggest that potentially alterable environmental factors influence genetic contributions, providing targets for disease prevention and treatment. Here, we review midlife risk factors for AD, and address the potential for therapeutic intervention in midlife.

Effect of monocyte chemoattractant protein-1 on murine bone marrow cells: proliferation, colony-forming ability and signal transduction pathway involved

Monocyte chemoattractant protein-1 (MCP-1) plays a crucial role in the migration and activation of leukocytes in both physiological and pathological contexts. In this paper, we report the in vitro effect of MCP-1 on myeloid haematopoiesis. MCP-1-treated murine nonadherent bone marrow cells (NABMCs) were assayed for in vitro proliferation and colony forming ability. It is observed that MCP-1 treatment in vitro caused an enhancement in the proliferation and colony forming ability of the murine NABMCs as compared to the untreated cells. This response was concentration-dependent and most effective at a dose of 100ng/ml MCP-1. In the presence of MCSF (200U/ml), GCSF (200U/ml), GMCSF (200U/ml) or IL-3 (200U/ml), the MCP-1-induced colony forming ability of the NABMCs was significantly augmented, indicating a synergistic effect of MCP-1 with these CSFs. However, irrespective of the CSFs used, MCP-1 stimulated the lineage-restricted differentiation of the murine BMCs into predominantly the granulocytic lineage. NABMCs cultured in medium alone formed minimal colonies. The probable signal transduction mechanism responsible for the MCP-1-induced NABMC proliferation/differentiation was also investigated. The results of the colony forming assay indicate that the protein kinase inhibitors, genistein (10&mgr;g/ml), chelenthryin chloride (10&mgr;M), wortmannin (200nM) and PD98059 (10&mgr;M) significantly blocked the in vitro colony forming ability of the MCP-1-treated NABMCs, while the phosphatase inhibitors, okadaic acid (10nM) and sodium orthovanadate (10&mgr;M) caused an increase in the BMC colony forming ability in response to MCP-1. These data suggests the involvement of the respective protein kinases and phosphatases in the above process. Correlating with this, the role of several signaling molecules likes Lyn, p42/44MAPK, PI3K and STAT5 has also been implicated in the signal cascade of murine NABMC proliferation/differentiation following MCP-1 treatment.

Regulation of nitric oxide production by murine peritoneal macrophages treated in vitro with chemokine monocyte chemoattractant protein 1

Monocyte chemoattractant protein 1 (MCP-1) is an important mediator of monocyte/macrophage recruitment and activation at the sites of chronic inflammation and neoplasia. In the current study, the role of nitrogen monoxide (NO) in the activation of murine peritoneal macrophages to the tumoricidal state in response to in vitro MCP-1 treatment and the regulatory mechanisms involved therein were investigated. Murine peritoneal macrophages upon activation with MCP-1 showed a dose- and time-dependent production of NO together with increased tumoricidal activity against P815 mastocytoma cells. N-monomethyl-l-arginine (L-NMMA), a specific inhibitor of the l-arginine pathway, inhibited the MCP-1-induced NO secretion and generation of macrophage-mediated tumoricidal activity against P815 (NO-sensitive, TNF-resistant) cells but not the L929 (TNF-sensitive, NO-resistant) cells. These results indicated l-arginine-dependent production of NO to be one of the effector mechanisms contributing to the tumoricidal activity of MCP-1-treated macrophages. Supporting this fact, expression of iNOS mRNA was also detected in the murine peritoneal macrophages upon treatment with MCP-1. Investigating the signal transduction pathway responsible for the NO production by the MCP-1-activated murine peritoneal macrophages, it was observed that the pharmacological inhibitors wortmannin, H-7 (1-(5-isoquinoline sulfonyl)-2-methyl piperazine dihydrochloride), and PD98059 blocked the MCP-1-induced NO production, suggesting the probable involvement of phosphoinositol-3-kinase, protein kinase C, and p42/44 MAPkinases in the above process. Various modulators of calcium and calmodulin (CaM) such as EGTA, nifedipine, TMB-8 (3,4,5-trimethoxybenzoic acid-8-(diethylamino)octyl ester), A23187, and W-7 (N-(6-aminohexyl)-5-chloro-1-napthalenesulfonamide) were also found to modulate the in vitro macrophage NO release in response to MCP-1. This observation indicated the regulatory role of calcium/CaM in the process of MCP-1-induced macrophage NO production. Similarly, the role of serine/threonine and protein tyrosine phosphatases in the above pathway was suggested using the specific inhibitors of these phosphatases, okadaic acid and sodium orthovanadate.

MAPK and Akt act cooperatively but independently on hypoxia inducible factor-1alpha in rasV12 upregulation of VEGF

Oncogenic ras upregulates the expression of VEGF through the activation of the transcriptional enhancer hypoxia inducible factor-1alpha (HIF-1alpha) by a still poorly understood mechanism. Here, we demonstrate that both the Raf/MEK/MAPK and the PI3 kinase/Akt signaling pathways potently and additively stimulate the expression from a hypoxia response element (HRE) within the 5'flanking region of the VEGF promoter. Interestingly, while MAPK appears to specifically upregulate the transactivation activity of HIF-1alpha through direct phosphorylation of its regulatory/inhibitory domain, GSK-3, a downstream target of Akt, directly phosphorylates the HIF-1alpha oxygen-dependent degradation domain. These results suggest a novel mechanism whereby two divergent signaling pathways emerging from Ras may cooperatively but independently regulate the activity of a HIF-1alpha, thereby promoting the expression of a potent angiogenic mediator.

The Kaposi's sarcoma-associated herpesvirus G protein-coupled receptor promotes endothelial cell survival through the activation of Akt/protein kinase B

The Kaposi's sarcoma-associated herpesvirus G protein-coupled receptor (KSHV-GPCR) is a key molecule in the pathogenesis of Kaposi's sarcoma, playing a central role in the promotion of vascular endothelial growth factor (VEGF)-driven angiogenesis and spindle cell proliferation. We previously have shown that KSHV-GPCR has oncogenic potential when overexpressed in fibroblasts and is responsible for the expression and secretion of VEGF through the regulation of different intracellular signaling pathways (A. Sodhi et al., Cancer Res., 60: 4873-4880, 2000; C. Bais et al., Nature, 391: 86-89, 1998). Here, we describe that this constitutively active G protein-coupled receptor is able to promote cell survival in primary human umbilical vein endothelial cells and that this effect is independent of its ability to secrete VEGF because it is not prevented by the expression of antisense constructs for VEGF or the addition of VEGF-blocking antibodies. Instead we found that ectopic expression of KSHV-GPCR potently induces the kinase activity of Akt/protein kinase B in a dose-dependent manner and triggers its translocation to the plasma membrane. This signaling pathway requires the function of phosphatidylinositol 3'-kinase and is dependent on betagamma subunits released from both pertussis toxin-sensitive and -insensitive G proteins. Furthermore, we found that KSHV-GPCR is able to protect human umbilical vein endothelial cells from the apoptosis induced by serum deprivation and that both wortmannin and the expression of a kinase-deficient Akt K179M mutant are able to block this effect. Finally, we observed that the Akt K179M protein also inhibits the activation of nuclear factor-KB induced by KSHV-GPCR, suggesting that this transcription factor may represent one of the putative downstream targets for Akt in the survival-signaling pathway. These results provide further knowledge in the elucidation of the signal transduction pathways activated by KSHV-GPCR and support its key role in promoting the survival of viral-infected cells. Moreover, the present findings also emphasize the importance of this G protein-coupled receptor in the development of KSHV-related neoplasias.

Age-associated hematopoietic alterations in the spleen of tumor-bearing hosts

The present investigation was carried out to study the effect of tumor growth on the spleen of an aged host. Dalton's lymphoma (DL), a spontaneous T cell lymphoma, was grown in mice of different age groups classified as young, adult or old on the basis of their reproductive status. Splenocytes obtained from normal and tumor-bearing young, adult and old mice were checked for an in vitro blastogenic response to concanavalin A (Con A), colony-forming ability and apoptosis. There was an enhanced apoptosis of splenocytes and a concomitant inhibition of splenocyte blastogenesis and their responsiveness to the mitogenic stimulus of Con A in aged mice. The counts of granulocyte macrophage- and macrophage-colony forming units were significantly enhanced in the spleen of tumor-bearing adult mice. It is proposed that the DL-growth-dependent increase in the size of the spleen in adult mice is due to an increased blastogenesis of splenocytes, which, however, may not be applicable in the case of old tumor-bearing mice. The role of splenic macrophages in the regulation of the functions of the spleen by macrophage-derived NO is shown.

Ascitic growth of a spontaneous transplantable T cell lymphoma induces thymic involution. 2. Induction of apoptosis in thymocytes

It has been observed that the progressive ascitic growth of a transplantable T cell lymphoma of spontaneous origin, designated as Dalton's lymphoma (DL), induces inhibition of various immune responses and is associated with an involution of the thymus accompanied by a massive depletion of the cortical region and alteration in the distribution of thymocytes, with a decrease in CD4+CD8+, CD4+CD8- and CD4-CD8+ thymocytes. Morphological evaluation of thymocytes from DL-bearing mice revealed that with the progression of DL, a majority of thymocytes exhibited morphological features characteristic of apoptotic cell death, which included contracted cell bodies, condensed, uniformly circumscribed and densely stained chromatin, and membrane-bound apoptotic bodies containing one or more nuclear fragments. Quantitative and qualitative analysis of the DNA extracted from the thymocytes of DL-bearing mice revealed DNA fragmentation that increased concomitantly with the progression of DL and showed an oligonucleosomal DNA ladder pattern upon agarose gel electrophoresis, a hallmark of apoptotic cell death. Attempts to identify apoptotic factor(s) showed that the serum of DL-bearing mice contained certain soluble factor(s) that augmented the induction of apoptotis in thymocytes in a time- and dose-dependent manner. Although DL cells or their products, such as DL-cell-conditioned medium or DL-cell-free ascitic fluid, could also induce apoptosis of thymocytes in vitro, the magnitude of the same was consistently lower than that induced by the serum of DL-bearing mice. Further, elucidation of the mechanism of apoptosis induction in thymocytes with respect to the involvement of apoptosis-related genes revealed that the death pathway followed an interleukin-1 beta-converting-enzyme-dependent, Fas-mediated apoptotic cascade, with a concomitant increase in the protein products of the bax, bad, p53, fas and fasL genes and cleavage of the 23-kD N-terminal fragment of Bcl-2 that exhibited Bax-like death effector properties.

Ascitic growth of a spontaneous transplantable T cell lymphoma induces thymic involution. 1. Alterations in the CD4/CD8 distribution in thymocytes

We have previously shown that the progressive ascitic growth of a transplantable T cell lymphoma of spontaneous origin in a murine host, designated as Dalton's lymphoma (DL), induces the inhibition of various immune responses. In a quest to understand the mechanism(s) of tumor-growth-dependent immunosuppression, we were interested to investigate if the thymus, the center for the differentiation of immunocompetent T cells, undergoes any alteration concomitant with the growth of DL. Thus, DL was grown as an ascitic tumor in BALB/c mice for a period of 4 or 17 days, designated as the early and late tumor stages, respectively, and the thymuses were examined immediately after sacrifice of the animals on the 4th or 17th day of tumor transplantation. Progressive growth of DL was observed to be associated with thymic atrophy, as well as an involution of thymic organization and a depletion of cell mass. Histological sections of thymus from DL-bearing mice revealed a complete disintegration of the thymic architecture with a massive depletion of the cortical region and disappearance of the corticomedullary junctions. Flow cytometric analysis of alterations in the distribution of thymocytes revealed a decrease in CD4+CD8-, CD4-CD8+ and CD4+CD8+ cell populations, whereas the CD4-CD8- population showed an increase, suggesting an impairment in thymocyte differentiation at an early T cell maturation stage. Furthermore, tumor growth was shown to suppress the proliferation ability of thymocytes. Moreover, an increase in thymocytes of smaller size was also found with the progression of DL, which is an indication that a large fraction of thymocytes of a small, abnormal size could be apoptotic cells. Furthermore, the paper discusses the immunological implications of thymic atrophy in a host bearing a T cell lymphoma.

The Kaposi's sarcoma-associated herpes virus G protein-coupled receptor up-regulates vascular endothelial growth factor expression and secretion through mitogen-activated protein kinase and p38 pathways acting on hypoxia-inducible factor 1alpha

The elucidation of the molecular mechanisms governing the transition from a nonangiogenic to an angiogenic phenotype is central for understanding and controlling malignancies. Viral oncogenes represent powerful tools for disclosing transforming mechanisms, and they may also afford the possibility of investigating the relationship between transforming pathways and angiogenesis. In this regard, we have recently observed that a constitutively active G protein-coupled receptor (GPCR) encoded by the Kaposi's sarcoma-associated herpes virus (KSHV)/human herpes virus 8 is oncogenic and stimulates angiogenesis by increasing the secretion of vascular endothelial growth factor (VEGF), which is a key angiogenic stimulator and a critical mitogen for the development of Kaposi's sarcoma. Here we show that the KSHV GPCR enhances the expression of VEGF by stimulating the activity of the transcription factor hypoxia-inducible factor (HIF)-1alpha, which activates transcription from a hypoxia response element within the 5'-flanking region of the VEGF promoter. Stimulation of HIF-1alpha by the KSHV GPCR involves the phosphorylation of its regulatory/inhibitory domain by the p38 and mitogen-activated protein kinase (MAPK) signaling pathways, thereby enhancing its transcriptional activity. Moreover, specific inhibitors of the p38 (SKF86002) and MAPK (PD98059) pathways are able to inhibit the activation of the transactivating activity of HIF-1alpha induced by the KSHV GPCR, as well as the VEGF expression and secretion in cells overexpressing this receptor. These findings suggest that the KSHV GPCR oncogene subverts convergent physiological pathways leading to angiogenesis and provide the first insight into a mechanism whereby growth factors and oncogenes acting upstream from MAPK, as well as inflammatory cytokines and cellular stresses that activate p38, can interact with the hypoxia-dependent machinery of angiogenesis. These results may also help to identify novel targets for the development of antiangiogenic therapies aimed at the treatment of Kaposi's sarcoma and other neoplastic diseases.

Activation of murine bone-marrow derived macrophages in vitro with Thymosin-alpha-1 to tumoricidal state: a comparative study on normal and tumour-bearing hosts

The present investigation establishes the ability of Thymosin alpha l (T alpha l) to activate murine bone-marrow derived macrophages (BMDMs) in vitro to tumoricidal state with concomitant release of NO, TNFalpha and IL-1. The T alpha l-induced cytotoxicity and the secretion of soluble lytic factors were both dose- and time dependent. BMDMs cultured from the Dalton's Lymphoma bearing mice (DL-BMDMs) exhibited reduced cytolytic activity towards DL-tumour target cells on activation with T alpha l as compared to the BMDMs obtained from normal mice (N-BMDMs). The DL-BMDMs displayed enhanced TNFalpha and IL-1 release as compared to the N-BMDMs when treated with T alpha l. On the other hand, it is observed that the production of NO and the expression of iNOS was higher in the N-BMDMs as compared to the DL-BMDMs on treatment with T alpha l. Although T alpha l could trigger the tumoricidal functions of BMDMs from normal and DL-tumor bearing hosts, the progressive growth of DL-tumour in ascitic form leads to an alteration in the antitumour response of macrophages. These observations further suggest that a disregulation in the production of inflammatory cytokines like TNF-alpha, IL-1 and the inhibition of NO production in response to DL growth may mutually contribute in explaining the tumour-induced immunosuppression as observed in the DL-bearing mice.

Mechanism of thymocyte apoptosis induced by serum of tumor-bearing host: the molecular events involved and their inhibition by thymosin alpha-1

The observations presented in this paper indicate that serum of Dalton's lymphoma (DL) bearing mice contained certain soluble factor(s) that augmented the induction of apoptosis in thymocytes in a time- and dose-dependent manner. DL-ascitic fluid and DL-conditioned medium could also induce apoptosis of thymocytes in vitro, though the magnitude of the same was consistently lower than that induced by serum of DL-bearing mice. It was observed that the interaction of FasL and TNFalpha with their respective receptors could trigger apoptosis in thymocytes. Elucidation of the signal transduction mechanism revealed involvement of protein tyrosine kinase, protein kinase C and ser/thr phosphatases with concomitant increase in the level of protein products of apoptosis associated genes p53, bax, bad, fas and fas ligand and cleavage of N-terminal 23 kDa fragment of Bcl-2 that exhibited Bax-like death effector properties. Further, we report, for the first time, the ability of thymosin alpha-1, an immunopotentiating thymic hormone, to antagonize apoptosis in thymocytes induced by factors present in serum of DL-bearing mice. The underlying mechanism of tumor serum induced apoptosis inhibition by thymosin alpha-1 was also analyzed. The signal transduction cascade evoked by thymosin alpha-1 involves activation of protein kinase C with a decrease in the level of protein products of proapoptotic genes like bax and bad and increase in the protein products of bcl-2 gene.

Impairment of T-cell functions with the progressive ascitic growth of a transplantable T-cell lymphoma of spontaneous origin

It has been observed that the progressive ascitic growth of a transplantable T-cell lymphoma of spontaneous origin, designated Dalton's lymphoma (DL), in a murine host induces inhibition of various immune responses and is associated with an involution of thymus accompanied by a massive depletion of the cortical region and alteration in the distribution of thymocytes caused by tumour serum-dependent induction of apoptosis with a decrease of CD4(+)CD8(+), CD4(+)CD8(-) and CD4(-)CD8(+) thymocytes. Here, we report that thymocytes of DL-bearing mice are defective in their proliferative ability and in their response to non-specific mitogenic stimulus in vitro. Also, antigen-specific T-cell proliferative ability representing the fundamental T(H) function declines under DL-bearing conditions and upon treatment with serum of DL-bearing mice. Moreover, a significant inhibition of T-cell cytolytic activity with a decreased ability to produce interferon gamma is shown by the T cells of DL-bearing mice and by the T cells treated with DL-ascitic fluid, DL-conditioned medium or serum of DL-bearing mice. Further, addition of interleukin-2 and anti-interleukin-10 to the cultures of thymocytes treated with serum of DL-bearing mice is found to inhibit the induction of apoptosis in thymocytes, a phenomenon associated with the progression of DL growth. Analysis of the results indicates an immune deviation with the predominance of a T(H2)-type response with the progression of tumour. We further discuss the possible mechanisms that may explain the observed tumour-induced diminution of T-cell immunity.

Anticancer drug-induced apoptosis in human monocytic leukemic cell line U937 requires activation of endonuclease(s)

Anticancer agents effect tumor cell killing both in vivo and in vitro through the induction of apoptosis. Endonuclease-mediated internucleosomal DNA fragmentation, the most widely used biochemical marker of apoptosis, has been shown to play a central role in apoptosis in many experimental systems. In the present investigation, we report that activation of endonuclease(s) leading to oligonucleosomal DNA fragmentation is common and an essential event in apoptosis, induced by different anticancer drugs, adriamycin, etoposide and cisplatin. The endonuclease inhibitors aurintricarboxylic acid and zinc ion prevented apoptotic cell death in human monocytic leukemic cell line U937, as documented by DNA fragmentation, morphological and nuclear alterations, and cell viability assay. Additional studies suggest endonuclease(s)-mediated DNA fragmentation may not play a central role in apoptosis in the same cell line in response to other inducers such as heat shock and cells may undergo cell death showing all morphological features of apoptosis even in the absence of DNA fragmentation.

Prior immunity to a carrier enhances antibody responses to hCG in recipients of an hCG-carrier conjugate vaccine

Pre-sensitization with carrier often leads to epitopic suppression of subsequent anti-hapten antibody responses. To ascertain whether epitopic suppression occurs in humans, we examined the effect of pre-existing anti-carrier immunity on antibody responses to hCG in volunteers of a clinical trial of an hCG-based conjugate birth-control vaccine. When we studied the correlation between pre-vaccination anti-carrier immunity and post-vaccination anti-hCG responses, we found that prior immunity to the carriers did not lead to epitopic suppression of anti-hCG responses. On the contrary, it was found that prior immunity to TT, one of the two carriers used in this vaccine, led to enhancement of anti-hCG responses. Our data indicates that prior immunity to the carriers may not be detrimental to the performance of conjugate vaccines, and may actually be beneficial in some cases.

Expression and activation of RAS and mitogen-activated protein kinases in macrophages treated in vitro with cisplatin: regulation by kinases, phosphatases and Ca2+/calmodulin

Cisplatin (cis-dichlorodiammineplatinum II), a potent antitumour compound, stimulates immune responses by activating monocytes/macrophages and other cells of the immune system. However, the exact mechanism by which cisplatin activates these cells is poorly characterized and attempts are being made to understand this mechanism. Previous studies from this laboratory have shown that Lyn, a protein tyrosine kinase of the src family, and nuclear factor (NF)-kappaB are involved in cisplatin-induced macrophage activation. Recent studies suggest that the RAS and mitogen-activated protein (MAP) kinases function as a connecting link between activated lyn and NF-kB, which raises the possibility of their involvement in cisplatin-induced macrophage activation. Therefore, this study was undertaken to investigate the effect of cisplatin treatment on the expression/activation of RAS (a low molecular weight GTP-binding protein) and MAP kinases in murine peritoneal macrophages. The underlying mechanism of expression/activation of RAS and MAP kinases in cisplatin-treated macrophages was also investigated. Immunoblotting and immune-complex kinase assays revealed that cisplatin treatment of macrophages leads to increased expression/activation of RAS and MAP kinases, with optimal expression/activation at 15 min of treatment. Using a battery of specific inhibitor/modulators of different signalling molecules, this study shows that expression and activation of MAP kinases are two unrelated processes. It was also observed that kinase (protein tyrosine and protein kinase C) inhibitor and Ca2+/calmodulin antagonist inhibit expression/activation of RAS/MAP kinases in macrophages, whereas phosphatases (protein tyrosine and serine/threonine) inhibitor up-regulate these kinases.

Age-dependent alterations in the tumoricidal functions of tumor-associated macrophages

Age-dependent tumor cytolytic functions of tumor-associated macrophages (TAM) obtained from mice bearing different stages of Dalton's lymphoma (DL), a spontaneous T cell lymphoma, were studied. Mice were separated into three groups on the basis of their reproductive status as indicator of age: young (prereproductive); adult (reproductive) and old (postreproductive). DL was injected (1 x 10(5) cells/mouse) intraperitoneally in mice; days 4, 10 and 16 from the day of injection were referred to as early, mid and late tumor stages, respectively. Normal peritoneal macrophages and macrophages isolated from the ascitic fluid of DL-bearing mice (TAM); 1 x 10(5) cells activated with lipopolysaccharide (LPS) plus interferon-gamma (IFN-gamma) and assayed for age-dependent alterations in macrophage tumoricidal functions such as: tumor cell binding, cytotoxicity, production of reactive nitrogen intermediates (RNI), expression of inducible nitric oxide synthase (iNOS) and oncostatin-M (OSM) were observed. TAM from old mice were observed to be inhibited with respect to tumor cell binding, cytotoxicity and expression of iNOS and OSM, as compared to macrophages of young and adult mice. TAM obtained from early tumor stages showed augmented tumor cytotoxicity as well as enhanced expression of iNOS and OSM in all the age groups. This effect was most pronounced in the TAM obtained from adult mice and least in the TAM obtained from old mice. The reasons for the observed difference are discussed. These observations should be helpful in understanding the effect of progressive tumor growth and age on the functions of TAM and their responsiveness towards therapeutic manipulations.

Antigen presentation by cisplatin-activated macrophages: role of soluble factor(s) and second messengers

Cisplatin [cis-dichlorodiammine platinum (II)], a potent anti-tumour compound, stimulates immune responses by activating macrophages and other cells of the immune system. The mechanism by which cisplatin activates these cells is poorly characterized. Present investigations were undertaken to study the mechanism of antigen presentation by cisplatin-treated macrophages. Cisplatin-treated macrophages showed a biphasic pattern of antigen presentation to keyhole limpet haemocyanin (KLH)-primed T cells. The second phase of antigen presentation was not due to the continuous presence of cisplatin in the culture medium; rather, it was induced by soluble factors released by cisplatin-treated macrophages. Co-incubation of macrophages with cisplatin and inhibitor of serine/threonine or protein tyrosine phosphatase resulted in an augmentation of cisplatin-induced antigen presentation. In contrast, treatment of macrophages with cisplatin and inhibitor of protein kinase C or protein tyrosine kinase inhibited cisplatin-induced antigen presentation. These observations suggest that antigen presentation by cisplatin-treated macrophages is regulated by reversible action of protein phosphatases and kinases. The antigen-presenting ability of cisplatin-treated macrophages was also inhibited by EGTA, nifedipine, TMB-8, W-7 and calmidazolium, suggesting the probable involvement of Ca2+, calmodulin and calmodulin-dependent kinases in this process.

Expression and activation of lyn in macrophages treated in vitro with cisplatin: regulation by kinases, phosphatases and Ca2+/calmodulin

Cisplatin [cis-dichlorodiammine platinum (II)], a potent chemoimmunotherapeutic drug, activates macrophages to tumoricidal state which is inhibited by protein tyrosine kinase(s) inhibitor. Cisplatin induces protein tyrosine phosphorylation of a number of cellular proteins suggesting the involvement of protein tyrosine kinase(s) in the activation process of macrophages. Therefore, the effect of cisplatin treatment on the expression and activation of lyn, a protein tyrosine kinase of src family, in macrophages was investigated. The underlying mechanism of lyn expression and activation was also analyzed. Cisplatin treatment increased lyn expression and activation in macrophages within 5 min of treatment. The expression and activation of lyn were observed to be biphasic processes in cisplatin-treated macrophages with the first peak appearing at 15 min and the second peak at 2 h of treatment. The appearance of second phase of lyn activation and second phase of lyn expression were two unrelated processes. The second peak of lyn activation was produced by the autocrine action of some soluble product(s) of cisplatin-treated macrophages, whereas the second phase of lyn expression was due to some intracellular factor. It was further observed that cisplatin-induced lyn expression and activation involves serine/threonine phosphatases 1/2A, protein tyrosine phosphatases, protein tyrosine kinase and protein kinase C. It was also observed that Ca2+/calmodulin and calmodulin-dependent kinases are involved in the regulation of cisplatin-induced lyn expression and activation in macrophages.

LFA-1-dependent tumoricidal activity of cisplatin-treated macrophages

The role of leucocyte function associated antigen-1 (LFA-1) (CD11a/18) in the tumoricidal activity of cisplatin-treated macrophages was investigated. Anti-LFA-1 antibodies inhibited cisplatin-induced macrophage cytotoxicity towards three different tumour cell lines. The decrease in tumoricidal activity of cisplatin-treated macrophages was attributed to their decreased binding to tumour cells in the presence of anti-LFA-1 (CD11a/18) antibodies. Western blot analysis revealed that cisplatin treatment leads to the expression of LFA-1 on macrophages which otherwise remains non-detectable. Because there is no information regarding the mechanism of cisplatin-induced LFA-1 expression and tumour cell binding by macrophages, the role of various second messenger molecules in these processes was investigated. Results suggest that protein phosphatase 2A (PP2A) is not involved in these processes whereas protein tyrosine phosphatases (PTP) negatively regulate LFA-1 expression and tumour-cell binding of cisplatin-treated macrophages. Inhibitors of protein phosphatase 1 (PP1), protein kinase C (PKC), protein tyrosine kinase (PTK), calmodulin and calmodulin-dependent kinase-II (CamK II) prevented LFA-1 expression on cisplatin-treated macrophages. A comparison with earlier results indicated that LFA-expression follows a distinct signalling pathway which is separate from the signalling pathway involved in NO or tumour necrosis factor/interleukin-1 (TNF/IL-1) expression in cisplatin-stimulated macrophages.

Mechanism of NF-kappa B translocation in macrophages treated in vitro with cisplatin

In murine peritoneal macrophages cisplatin (cis-dichlorodiammine platinum (II)), a potent chemoimmunotherapeutic drug modulates the expression of several cytokines which contain nuclear factor kappa B (NF-kappaB) binding site suggesting the involvement of NF-kappaB in the activation process of macrophages by cisplatin. Therefore, we analyzed the effect of cisplatin treatment on NF-kappaB expression and activation in macrophages. The underlying mechanism of NF-kappaB translocation was also investigated. Cisplatin treatment increased cellular NF-kappaB content in macrophages treated for 60 min. NF-kappaB translocation was biphasic. Cisplatin-induced translocation of NF-kappaB took place within 5 min and reached its optimum by 15 min. A second phase of nuclear transfer of NF-kappaB was observed at 3 h of cisplatin treatment which was dependent on H2O2 production in cisplatin-treated macrophages. It was observed that cisplatin-induced NF-kappaB translocation involves serine/threonine phosphatases 1/2A, protein tyrosine phosphatases and genestein sensitive protein tyrosine kinase activities. H-7 sensitive protein kinase C do not fall in the signaling pathway of cisplatin leading to the translocation of NF-kappaB. Both cytosolic and membrane-associated factors were required for the induction of NF-kappaB translocation by cisplatin in macrophages.