Reduced lung cancer burden by selective immunomodulators elicits improvements in muscle proteolysis and strength in cachectic mice

Abstract

Identification of to what extent tumor burden influences muscle mass independently of specific treatments for cancer‐cachexia remains to be elucidated. We hypothesized that reduced tumor burden by selective treatment of tumor with immunomodulators may exert beneficial effects on muscle wasting and function in mice. Body and muscle weight, grip strength, physical activity, muscle morphometry, apoptotic nuclei, troponin‐I systemic levels, interleukin‐6, proteolytic markers, and tyrosine release, and apoptosis markers were determined in diaphragm and gastrocnemius muscles of lung cancer (LP07 adenocarcinoma cells) mice (BALB/c) treated with monoclonal antibodies (mAbs), against immune check‐points and pathways (CD‐137, cytotoxic T‐lymphocyte associated protein‐4, programed cell death‐1, and CD‐19; N = 10/group). Nontreated lung cancer cachectic mice were the controls. T and B cell numbers and macrophages were counted in tumors of both mouse groups. Compared to nontreated cachectic mice, in the mAbs‐treated animals, T cells increased, no differences in B cells or macrophages, the variables final body weight, body weight and grip strength gains significantly improved. In diaphragm and gastrocnemius of mAbs‐treated cachectic mice, number of apoptotic nuclei, tyrosine release, proteolysis, and apoptosis markers significantly decreased compared to nontreated cachectic mice. Systemic levels of troponin‐I significantly decreased in treated cachectic mice compared to nontreated animals. We conclude that reduced tumor burden as a result of selective treatment of the lung cancer cells with immunomodulators elicits per se beneficial effects on muscle mass loss through attenuation of several biological mechanisms that lead to increased protein breakdown and apoptosis, which translated into significant improvements in limb muscle strength but not in physical activity parameters.

Muscle Phenotype, Proteolysis, and Atrophy Signaling During Reloading in Mice: Effects of Curcumin on the Gastrocnemius

“…As such, in models of disuse muscle atrophy and wasting, a rise in the levels of markers of proteolysis, autophagy, apoptosis, oxidative stress, and epigenetic modifications have been shown in muscles of both patients [2,[6][7][8][9][10][11] and animals [12][13][14][16][17][18][19][20][21][22]. Additionally, alterations in the structure of the myofibers along with a reduction in their size have also been demonstrated in muscles following periods of inactivity [12][13][14][16][17][18][19][20][21][22].The study of the kinetics of the pathophysiological and biological events whereby the loss of muscle mass takes place following periods of disuse is important [23][24][25]. In this regard, the sequence of the expression of markers of proteolysis, apoptosis, autophagy, signaling, of structural alterations and fiber type switches, and that of impaired function have already been described in previous investigations [23][24][25].Post-translational modifications of transcription factors that signal proteolytic activation in muscles were described in several models of muscle atrophy [24][25][26].…”

Immunotherapy with Monoclonal Antibodies in Lung Cancer of Mice: Oxidative Stress and Other Biological Events

“…Immunohistochemical techniques were applied on tumor sections in order to explore expression of the proliferation marker Ki-67 and T cells, following previous methodologies [8,12,13,16,33,36,37,38,42,43]. Briefly, for all the target antigens, tumor cross-sections were deparaffinized and then antigen retrieval was carried out by heating slides in a water bath in Tris/Ethylenediaminetetraacetic acid (EDTA) buffer, pH 9, for 30 min (Ki-67 and CD3) or in a pressure-cooker (CD4, CD8) in 0.1 M citrate buffer, pH 6, for 15 min.…”

“…Terminal deoxynucleotidyl transferase- mediated uridine 5′-triphosphate (UTP) nick- end labelling (TUNEL) assay. In tumor paraffin-embedded sections, apoptotic nuclei were identified using the TUNEL assay (In Situ Cell Death Detection Kit, POD, Roche Applied Science, Mannheim, Germany) for all study groups following the manufacturer’s instructions and previous studies [38,43]. Briefly, this assay is based on the principle that during the apoptosis of nuclei, genomic DNA may yield double-stranded, low molecular weight fragments as well as single-strand breaks (nicks) in high molecular weight DNA.…”

“…In each tumor cross-section, the TUNEL-positive nuclei and the total number of nuclei were counted blindly by two independent observers, who were previously trained for that purpose. Results were expressed as the ratio of total TUNEL positively-stained nuclei to the total number of counted nuclei, as also previously reported [38,43]. A minimum amount of 300 nuclei were counted in each tumor preparation.…”

B Cells and Tertiary Lymphoid Structures Influence Survival in Lung Cancer Patients with Resectable Tumors

“…Antitumor effects are exerted by T helper (Th) 1lymphocytes, whereas Th2 cells may inhibit the host immune system, thus, favoring tumor development and growth [11]. LC relapse and response to immunotherapy also rely on the balance between Th1 and Th2 immune phenotype [9,[12][13][14]. Moreover, Th1 and Th2 immune response may vary in patients with underlying respiratory diseases [15,16].…”