Pharmacological Approaches in an Experimental Model of Non-Small Cell Lung Cancer: Effects on Tumor Biology

Abstract

Lung cancer (LC) remains the leading cause of cancer mortality worldwide, and non-small cell LC (NSCLC) represents 80% of all LC. Oxidative stress and inflammation, autophagy, ubiquitin-proteasome system, nuclear factor (NF)-κB, and mitogen activated protein kinases (MAPK) participate in LC pathophysiology. Currently available treatment for LC is limited and in vivo models are lacking. We hypothesized that antioxidants and NF-κB, MAPK, and proteasome inhibitors may exert an antitumoral response through attenuation of several key biological mechanisms that promote tumorigenesis and cancer cell growth. Body and tumor weights, oxidative stress, antioxidants, inflammation, NF-κB p65 expression, fibulins, apoptosis, autophagy, tumor and stroma histology were evaluated in the subcutaneous tumor of LC (LP07 adenocarcinoma) BALB/c mice, with and without concomitant treatment with NF-κB (sulfasalazine), MEK (U0126), and proteasome (bortezomib) inhibitors, and N-acetyl cysteine (NAC). Compared to LC control mice, in subcutanous tumors, the four pharmacological agents reduced oxidative stress markers and tumor proliferation (ki-67).Inflammation and NF-κB p65 expression were attenuated by NF-κB and MAPK inhibitors, and the latter also enhanced apoptotic markers. Catalase was induced by the three inhibitors, while bortezomib also promoted superoxide dismutase expression. NF-κB and MEK inhibitors significantly reduced tumor burden through several biological mechanisms that favored tumor degradation and attenuated tumor proliferation. These two pharmacological agents may enhance the anti-tumor activity of selectively targeted therapeutic strategies for LC. Proteasomal inhibition using bortezomib rather promotes tumor degradation, while treatment with antioxidants cannot be recommended. This experimental model supports the use of adjuvant drugs for the improvement of LC treatment.Word count: 250

Oxidative Stress as a Mediator of the Immunomodulation Exerted by Monoclonal Antibodies in the Treatment of Lung Cancer in Mice

“…These results suggest that cell cycle arrest probably due to alterations in cyclin expression levels may account for the reduced levels of Ki-67-positively stained nuclei encountered in the adenocarcinoma cells of the treated tumor-bearing mice. Moreover, these findings are also in agreement with previous investigations, in which expression levels of Ki-67 were significantly reduced (34%) in the tumors of mice treated with several selective inhibitors of cell survival pathways [12], in those from transgenic mice deficient for either poly(ADP-ribose) polymerases (PARP)-1 and -2 enzymes [26], and in those of rodents treated with pharmacological inhibitors of PARP activity [41]. Taken together, these results are also very consistent with the above-mentioned reduced tumor area and weight seen in the tumorbearing mice treated with the immunomodulators at the end of the study period.…”

“…In the present investigation, levels of the antioxidant enzyme SOD1, but not those of SOD2 or catalase, were significantly greater in the tumors of the lung cancer-bearing mice treated with the monoclonal antibodies. These results are in line with those encountered in the tumors of mice treated with the proteasome inhibitor bortezomib [12]. The rise in the expression of cytosolic SOD1 levels may have been a response to counterbalance the deleterious effects of increased oxidative stress in the tumor cells as previously suggested [12].…”

“…These results are in line with those encountered in the tumors of mice treated with the proteasome inhibitor bortezomib [12]. The rise in the expression of cytosolic SOD1 levels may have been a response to counterbalance the deleterious effects of increased oxidative stress in the tumor cells as previously suggested [12]. A rise in the autophagy marker LC3B was observed in the tumor cells of the mice treated with the immunomodulators compared to non-treated control rodents.…”

Stromal markers of activated tumor associated fibroblasts predict poor survival and are associated with necrosis in non-small cell lung cancer

“…Fibrillar collagens were stained with PSR, whereas α-SMA and Ki-67 were stained by immunohistochemistry. α-SMA and PSR stainings were conducted with the Bond automated system (Leica Microsystems) as described [19,20]. Nuclei were counterstained with hematoxylin.…”

“…Similarly, images of PSR staining visualized with polarized light (PSR-PL) were converted into greyscale, inverted, binarized and used to compute the percentage (%) of positive area, which was averaged for each patient to elicit the final percentage as PSR-PL%. The number of positively stained nuclei for Ki-67 was counted and expressed as a percentage (Ki-67%) as described [20].…”