Amantadine acetylation may be effected by acetyltransferases other than NAT1 or NAT2

Current and Future Development in Lung Cancer Diagnosis

Lung cancer is the leading cause of cancer-related deaths in North America and other developed countries. One of the reasons lung cancer is at the top of the list is that it is often not diagnosed until the cancer is at an advanced stage. Thus, the earliest diagnosis of lung cancer is crucial, especially in screening high-risk populations, such as smokers, exposure to fumes, oil fields, toxic occupational places, etc. Based on the current knowledge, it looks that there is an urgent need to identify novel biomarkers. The current diagnosis of lung cancer includes different types of imaging complemented with pathological assessment of biopsies, but these techniques can still not detect early lung cancer developments. In this review, we described the advantages and disadvantages of current methods used in diagnosing lung cancer, and we provide an analysis of the potential use of body fluids as carriers of biomarkers as predictors of cancer development and progression.

Use of amantadine in the evaluation of response to chemotherapy in lung cancer: a pilot study

Aim:

The assessment of tumor response to therapy is of critical importance as it permits for a prospective end point evaluation and provides a guide to clinicians for making future treatment decisions. However, current practices in early evaluation of chemotherapy are insufficient. Amantadine is a substrate for SSAT-1. The present pilot study tests the hypothesis that SSAT-1 activity within the tumor, as measured by plasma acetylamantadine concentrations, can be used to monitor patient response to therapy.

Results:

In cases with evidence of disease response, there was a reduction in the plasma acetylamantadine concentration at 4 h by approximately 32%. There was a mean increase of approximately 34% at the 4 h collection in the nonresponders.

Conclusion:

Although large-scale studies are required these findings suggest that the amantadine test could allow for determination of the efficacy of therapeutic interventions earlier, providing an effective test to assess response to treatment and for better management of patients.

Aim: It is very important to get early information on the effectiveness of tumor treatment such that clinicians have a better understanding and decide on the next treatment regimen. Current methods are not sufficient to assess whether chemotherapy is effective early during a treatment cycle. We have previously used the presence of the acetylated metabolite of the drug amantadine in urine of patients diagnosed with lung cancer as a biomarker for disease. In the present study, our goal was to test the hypothesis that tumor responsiveness to therapy could be assessed by monitoring changes in the levels of the acetylated form of amantadine in the blood during the course of treatment. Results: In 70% of the patients we were able to relate disease progression or remission/stability to the levels of the acetylated form of amantadine in the blood. Conclusion: Although a larger study with a greater number of patients is required, our test could be used as a simple and effective tool to assess response to treatment and to better tailor treatment of the patient as well as reduce side effects and costs.

Liquid Biopsy in Lung Cancer Screening: The Contribution of Metabolomics. Results of A Pilot Study

Background: Lung cancer is the most common cause of cancer-related deaths worldwide. Early diagnosis is crucial to increase the curability chance of the patients. Low dose CT screening can reduce lung cancer mortality, but it is associated with several limitations. Metabolomics is a promising technique for cancer diagnosis due to its ability to provide chemical phenotyping data. The intent of our study was to explore metabolomic effects and profiles of lung cancer patients to determine if metabolic perturbations in the SSAT-1/polyamine pathway can distinguish between healthy participants and lung cancer patients as a diagnostic and treatment monitoring tool. Patients and Methods: Plasma samples were collected as part of the SSAT1 Amantadine Cancer Study. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify and quantify metabolite concentrations in lung cancer patient and control samples. Standard statistical analyses were performed to determine whether metabolite concentrations could differentiate between healthy subjects and lung cancer patients, as well as risk prediction modeling applied to determine whether metabolic profiles could provide an indication of cancer progression in later stage patients. Results: A panel consisting of 14 metabolites, which included 6 metabolites in the polyamine pathway, was identified that correctly discriminated lung cancer patients from controls with an area under the curve of 0.97 (95% CI: 0.875-1.0). Conclusion: When used in conjunction with the SSAT-1/polyamine pathway, these metabolites may provide the specificity required for diagnosing lung cancer from other cancer types and could be used as a diagnostic and treatment monitoring tool.

Predictive value and clinical significance of increased SSAT-1 activity in healthy adults

AIM

Spermidine/spermine N1-acetyltransferase (SSAT-1) regulates cell growth, proliferation and death. Amantadine is converted by SSAT-1 to acetylamantadine (AA). In our earlier studies, although SSAT-1 was activated in patients with cancer, a number of ostensibly healthy adult volunteers had higher than expected AA concentration. This study was therefore undertaken to examine the outlier group.

MATERIALS & METHODS

A follow up of urine analysis for AA by liquid chromatography-tandem mass spectrometry as well as clinical assessments and additional blood analyses were conducted.

RESULTS

In some of the outlier controls, higher than expected AA concentration was linked to increased serum carcinoembryonic antigen. Clinical and radiographic assessments revealed underlying abnormalities in other cases that could represent premalignant conditions. Hematology tests revealed elevations in white blood cells and platelets, which are markers of inflammation.

CONCLUSION

High urine concentration of AA could be used as a simple and useful test for screening of cancer in high-risk populations.

Use of amantadine as substrate for SSAT-1 activity as a reliable clinical diagnostic assay for breast and lung cancer

Aim:

Spermidine/spermine N¹-acetyltransferase (SSAT-1) plays a critical role in cell growth, proliferation and death, and is known to be activated in human cancer cells. Amantadine, a US FDA-approved antiviral drug, is a substrate for SSAT-1 and can be used to indirectly measure SSAT-1 activity because of its conversion to acetylamantadine (AA). This study was undertaken to further validate SSAT-1 activity in breast and lung cancer patients.

Results:

An increase in the urinary concentration of AA in lung and breast cancer patients was observed. The 0–2 h collection time point was determined to be optimal in revealing significant differences in urinary AA concentration between healthy controls and cancer patients.

Conclusion:

The high urine concentration of AA could be used as a simple and useful test for the detection of breast and lung cancer.

This study describes a novel noninvasive urine test for detecting and screening of breast and lung cancer using a safe and approved drug called amantadine. Higher concentration of the acetylated form of amantadine in the urine are detectable in the urine of both breast and lung cancer patients as compared with healthy adult volunteers. This test is simple and may serve as a useful tool for determining the presence of breast and lung cancer.

Spermidine/spermine N1-acetyltransferase-1 as a diagnostic biomarker in human cancer

Aim:

SSAT-1 is an enzyme that plays a critical role in cell growth. Amantadine, a FDA-approved antiviral drug, is a substrate for SSAT-1. The utility of amantadine as an agent to demonstrate elevated SSAT-1 activity linked to cancer was conducted.

Results:

High levels of SSAT-1 expression were measured in tumor human cell lines, and in breast, prostate and lung tumor tissue. An increase in the urinary levels of acetylated amantadine in cancer patients was observed.

Conclusion:

Increases in SSAT-1 contents in tumor tissue could be of value in targeting cancers with high SSAT-1 expression for confirmation/quantification. The high levels of acetylated amantadine could be used as a simple and useful screening test for the presence of cancer.

In response to cancer, cells tend to overproduce specific enzymes as a self-defense mechanism. By using a safe and reliable method to capture and measure the excess enzyme spermidine/spermine N1-acetyltransferase-1, the presence of cancer can be established. This study describes a novel approach of detecting and screening cancer noninvasively in the urine of cancer patients using a safe and approved drug called amantadine that acts as a smart-tracking agent. Higher levels of the acetylated form of amantadine are detectable in the urine of cancer patients, which may serve as a detection tool. In addition, increases in the amount of spermidine/spermine N1-acetyltransferase-1 in tumor tissue may provide a tool for determining the presence of cancer during pathology assessment.

Adventures in drug disposition: pas seulement pâté de foie

Interindividual variability in drug disposition and effect has served to confound the optimization of drug therapy. Over my career, I have focused on delineating mechanisms that contribute to this variability, with the goal of improving the benefit : risk ratio when drug therapy is chosen as an intervention strategy. In this manuscript, I present some of our experimental findings that I believe have contributed to an increased understanding of variability in drug disposition and efficacy.

Arylamine N-acetyltransferases and drug response

Arylamine N-acetyltransferases (NATs) play an important role in the interaction of competing metabolic pathways determining the fate of and response to xenobiotics as therapeutic drugs, occupational chemicals and carcinogenic substances. Individual susceptibility for drug response and possible adverse drug reactions are modulated by the genetic predisposition (manifested for example, by polymorphisms) and the phenotype of these enzymes. For all drugs metabolized by NATs, the impact of different in vivo enzyme activities is reviewed with regard to therapeutic use, prevention of side effects and possible indications for risk assessment by phenotyping and/or genotyping. As genes of NATs are susceptibility genes for multifactorial adverse effects and xenobiotic-related diseases, risk prediction can only be made possible by taking the complexity of events into consideration.