Characterizing tissue protein synthesis rates of non-small cell lung carcinomas in lung cancer patients

Cancer ranks as a leading cause of death worldwide, with an increased burden of
cancer incidence and mortality rates. Although lung cancer mortality rates have
decreased in Europe over the past decades, lung cancer has the highest
mortality rates among all types of cancer in men, and second-to-highest in
women. Compared to other types of cancer, lung cancer is associated with
relatively low survival rates after diagnosis. Lung cancer is caused by the
development of lung tumors and can be classified into two main types. The most
prevalent type of lung cancer is non-small cell lung carcinomas (NSCLCs).
NSCLCs compromise ~85% of all cases and can be further categorized into three
subclassifications: adenocarcinomas, squamous cell carcinomas, and large cell
carcinomas. All lung tumor types within the subclassifications of NSCLCs share
carcinomic features (i.e., uncontrolled cell growth and spread). However, the
differences between these tumor types are based on the location within the
lungs, the tendency to spread to lymph nodes, and other organs, and their
growth rate. Regarding lung cancer treatment and prognosis, tumor growth rate
is one of the most important aspects, as it is a key factor in the treatment
options for NSCLCs. Currently, treatment options for lung cancer are based on
the stage or progression of lung carcinomas. Understanding the processes and
extent by which lung tumor types regulate their growth is, therefore, important
for lung cancer treatment. The growth of all tissues, including tumors, is
regulated by the net difference between tumor tissue protein synthesis and
tumor protein tissue breakdown rates. It has been suggested that tumor tissue
protein synthesis rates are disproportionately greater than tumor tissue
protein breakdown rates, indicating that tumor tissue protein synthesis may
primarily reflect tumor growth responses. However, no study has determined
whether protein synthesis rates differ between healthy lung and lung tumor
tissue in vivo in lung cancer patients. Gaining more insight into lung tumor
growth regulation might increase the understanding lung tumor tissue
metabolism, improving lung cancer treatment and prognosis. In a recent study
from our research group (NL51743.096.14), we measured protein synthesis rates
in different organs and tissues collected from patients undergoing various
resection operations. Among the analyzed tissues were lung tumors, which
displayed an exceptionally wide variation in tissue protein synthesis rates
(0.07 to 2.77 %/h), especially when compared to healthy lung tissue (0.27 to
0.69 %/h). As such, no statistical difference was detected between the tissue
protein synthesis rates of healthy lung and lung tumor tissues (P = 0.20) After
subsequent analysis, it appeared as though adenocarcinomas, representing one
subclassification of NSCLC, tended to display greater tissue protein synthesis
rates (n=3, 0.73±0.18 %/h) when compared to the other subclassifications of
lung tumors (i.e., squamous cell carcinomas and large cell carcinomas, n=3,
0.12±0.18 %/h). Part of the difference may be explained by differences in tumor
diameter since the adenocarcinomas were relatively smaller (3-5 cm) when
compared to the other lung tumors (5-7 cm). In addition, we observed that tumor
protein synthesis rates positively correlated (P < 0.05) with systemic
inflammation (i.e., C-reactive protein concentration) and lung function (i.e.,
FEV1) of the included patients. However, while these data may suggest that
tumor tissue protein synthesis rates are associated with tumor- (i.e.,
subclassification, diameter) and patient-derived (i.e., inflammation, lung
function) parameters, a larger data set is required to determine potential
differences in protein synthesis rates between healthy lung and lung tumor
tissue and establish possible associations with various tissue and patient
parameters.

The current study aims to recruit a greater number of lung cancer patients to
measure tissue protein synthesis rates of non-small cell lung carcinomas and
healthy lung tissue. The protein synthesis rates of healthy lung tissue will be
compared to lung tumor tissue to establish the remodeling characteristics of
healthy versus cancerous lung tissues. By recruiting a greater number of
patients, we will also be able to establish whether tissue protein synthesis
rates of non-small cell lung carcinomas are associated with various tumor-
(i.e., size, subclassification) and patient-derived (i.e., inflammation, lung
function, smoking status, and smoking history) parameters.
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This study will be conducted in patients attending the Department of Surgery of
the Zuyderland Medical Centre, Heerlen for a video-assisted thoracic surgery
(VATS) lobectomy, due to the presence of a malignant tumor(s) in the lung. A
chronological description of this study:

1. Patients will be identified at the outpatient clinic of the Department of
Surgery of the Zuyderland Medical Centre, Heerlen. Patients will receive oral
and written information from a member of the clinical staff (i.e., nurse,
surgeon) at the outpatient clinic.

2. Interested patients who give consent, will be contacted by the MUMC+
researchers to give a brief explanation of the study and discuss further
questions.

3. After all information is provided, patients will be given at least 24 hours
to consider their participation. If there is no response from the patient after
this week of consideration, the MUMC+ researchers will contact the patient
again to confirm patient inclusion/exclusion.

4. Following inclusion, standard clinical measurements will be conducted,
including body mass and height, blood sample (C-reactive protein, CRP), whole
body PET-CT scan (muscle size and adipose tissue at L3), lung function (FEV1),
patient-reported weight loss in the last 6 months, handgrip strength, WHO
performance status assessment, and malnutrition universal screening tool.

5. Five days prior to the planned tumor resection surgery, informed consent
will be obtained from the patients before starting the deuterium oxide dosing
protocol. The dosing protocol begins with a dosing day in which 200 mL of 70%
deuterium oxide will be ingested in two 100 mL doses separated by 4 hours. For
each subsequent day, patients will ingest one 20 mL dose of 70% deuterium
oxide. Each day, patients will collect a saliva sample.

6. On the day of surgery, a blood sample will be drawn from the venous catheter
that is inserted for anesthetic administration. During the surgical procedure,
healthy lung and lung tumor tissue samples will be obtained from the resected
tissue. A small amount of muscle (50 mg) will be sampled from the serratus
anterior, which is exposed during the procedure. During subsequent analysis,
protein will be isolated from the healthy lung, lung tumor, and muscle tissue
samples and analyzed for the increase in 2H-alanine enrichment to determine
healthy lung, tumor, and muscle tissue protein synthesis rates over the 5-day
pre-operative period.

7. The study concludes for each patient when tissue samples are removed. Data
from the pathological reports of the patient and will be recorded.

The burden and risks involved in participating in this experiment are small.
The ingestion of deuterium oxide has been applied in numerous published studies
and is entirely safe and non-toxic in the amounts provided in the present
study. Tissue collection will occur during the tumor resection procedure during
surgery, which will already be planned as part of the subjects* course of
cancer treatment. Lung pleura (i.e., healthy lung tissue) and serratus anterior
muscle samples will also be obtained under anesthesia during surgical
procedure. The tissues are extracted during the standard procedure, meaning
that patients will not take on any extra burden by participating in study. The
data attained within this study may improve clinical practice, by gaining more
insight into one of the primary underlying processes controlling tumor growth
(i.e., lung tumor protein synthesis) and identifying possible associations with
tumor tissue- and patient-derived parameters.
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