Differentiation and programmed cell death-related intermediate biomarkers for the development of non-small cell lung cancer: a pilot study

Extracellular Matrix Stiffness in Lung Health and Disease

The extracellular matrix (ECM) provides structural support and imparts a wide variety of environmental cues to cells. In the past decade, a growing body of work revealed that the mechanical properties of the ECM, commonly known as matrix stiffness, regulate the fundamental cellular processes of the lung. There is growing appreciation that mechanical interplays between cells and associated ECM are essential to maintain lung homeostasis. Dysregulation of ECM-derived mechanical signaling via altered mechanosensing and mechanotransduction pathways is associated with many common lung diseases. Matrix stiffening is a hallmark of lung fibrosis. The stiffened ECM is not merely a sequelae of lung fibrosis but can actively drive the progression of fibrotic lung disease. In this article, we provide a comprehensive view on the role of matrix stiffness in lung health and disease. We begin by summarizing the effects of matrix stiffness on the function and behavior of various lung cell types and on regulation of biomolecule activity and key physiological processes, including host immune response and cellular metabolism. We discuss the potential mechanisms by which cells probe matrix stiffness and convert mechanical signals to regulate gene expression. We highlight the factors that govern matrix stiffness and outline the role of matrix stiffness in lung development and the pathogenesis of pulmonary fibrosis, pulmonary hypertension, asthma, chronic obstructive pulmonary disease (COPD), and lung cancer. We envision targeting of deleterious matrix mechanical cues for treatment of fibrotic lung disease. Advances in technologies for matrix stiffness measurements and design of stiffness-tunable matrix substrates are also explored. © 2022 American Physiological Society. Compr Physiol 12:3523-3558, 2022.

Time depended Bcl-2 inhibition might be useful for a targeted drug therapy

Background

Over expression of Bcl-2 is frequently observed in several types of cancers and it is one of the prognostic markers in breast cancer. The importance of the Bcl-2 protein as ideal therapeutic target is the dual role of inhibiting apoptosis and autophagy-mediated cell death. Thus, the bcl-2 targeting may be a strategy of choice to improve treatment efficacy and overcome drug resistance to cancer chemotherapy. For this reason, we designed the siRNA mediated silencing of the Bcl-2 gene in the MCF-7 breast cancer cell line.

Objectives

The purpose of this research was to investigate the effective Bcl-2 gene silencing by our homemade siRNA, more than previous study. Our data demonstrated that specific inhibition of the Bcl-2 by siRNA induces approximately more than 90 % gene silencing.

Methods

MCF-7 Cell lines were treated by homemade Bcl-2siRNA for the first time and control siRNA that was transfected with nanoparticle. The cells harvested at 24, 48 and 72 h and transcription level of Bcl-2 was examined by Real Time -PCR analysis. The drug sensitivity was detected by using LDH assay test. Finally Anexin V-FITC test was performed for evaluation of apoptosis.

Results

In the present study, results showed that targeting the specific sequence of the Bcl-2 by our homemade siRNA in the MCF7 cell line and its effect was more obvious in 24 h in contrast to 48 and 72 h.

Conclusions

However, we showed here a time dependent blocking of the bcl-2 transcript that might lead to cell dead due autophagy, and not necessarily to apoptosis.

Bcl-2-enhanced efficacy of microtubule-targeting chemotherapy through Bim overexpression: implications for cancer treatment

Bcl-2 is commonly overexpressed in tumors, where it is often associated with unfavorable outcome. However, it has also been linked to a favorable sensitivity to microtubule-targeting agents (MTAs). We show that Bcl-2-overexpressing lung and breast cancer cells were more sensitive to both paclitaxel and vinorelbine. Bcl-2 over-expression also significantly potentiated in vivo efficacy of paclitaxel, in terms of tumor volume decrease and survival benefits, in models of nude mice bearing lung cancer xenografts. To further investigate this favorable effect of Bcl-2, a genomic approach was taken. It revealed that Bcl-2 overexpression induced up-regulation of the proapoptotic protein Bim in lung cancer cells and that, conversely, Bcl-2 silencing decreased Bim expression level. A gene regulation study implicated the transcription factor Forkhead box-containing protein, class O3a in Bim up-regulation. Lastly, we show that Bim was responsible for MTA-triggered lung cancer cell death through a dynamin-related protein 1-mediated mitochondrial fragmentation. The Bcl-2-governed Bim induction evidence offers for the first time an explanation for the favorable higher sensitivity to treatment shown by Bcl-2-overexpressing cells. We suggest that Bim could be a powerful predictive factor for tumor response to MTA chemotherapy. Our data also give new insight into some failures in the efficacy of therapies targeted against Bcl-2.

Arsenic-induced malignant transformation of human keratinocytes: involvement of Nrf2

Arsenic is a well-known human skin carcinogen but the underlying mechanisms of carcinogenesis are unclear. Transcription factor Nrf2-mediated antioxidant response represents a critical cellular defense mechanism, and emerging data suggest that constitutive activation of Nrf2 contributes to malignant phenotype. In the present study when an immortalized, nontumorigenic human keratinocyte cell line (HaCaT) was continuously exposed to an environmentally relevant level of inorganic arsenite (100 nM) for 28 weeks, malignant transformation occurred as evidenced by the formation of highly aggressive squamous cell carcinoma after inoculation into nude mice. To investigate the mechanisms involved, a broad array of biomarkers for transformation were assessed in these arsenic-transformed cells (termed As-TM). In addition to increased secretion of matrix metalloproteinase-9 (MMP-9), a set of markers for squamous differentiation and skin keratinization, including keratin-1, keratin-10, involucrin, and loricrin, were significantly elevated in As-TM cells. Furthermore, As-TM cells showed increased intracellular glutathione and elevated expression of Nrf2 and its target genes, as well as generalized apoptotic resistance. In contrast to increased basal Nrf2 activity in As-TM cells, a diminished Nrf2-mediated antioxidant response induced by acute exposure to high doses of arsenite or tert-butyl hydroxyquinone occurred. The findings that multiple biomarkers for malignant transformation observed in As-TM cells, including MMP-9 and cytokeratins, are potentially regulated by Nrf2 suggest that constitutive Nrf2 activation may be involved in arsenic carcinogenesis of skin. The weakened Nrf2 activation in response to oxidative stressors observed in As-TM cells, coupled with acquired apoptotic resistance, would potentially have increased the likelihood of transmittable oxidative DNA damage and fixation of mutational/DNA damage events.

Expression of p53 protein and the apoptotic regulatory molecules Bcl-2, Bcl-XL, and Bax in locally advanced squamous cell carcinoma of the lung

OBJECTIVE

Bcl-2 family of proteins plays a critical role in the regulation of apoptosis. This pathway may be dysregulated leading to an altered ratio of pro- and anti-apoptotic molecules, hence rendering cells resistant to chemotherapy. The objective of this study was to understand the role of Bcl-2 family members in mediation of apoptosis in squamous cell carcinoma of the lung.

RESULTS

Bronchoscopically obtained lung biopsies from 30 cases of histologically proven squamous cell carcinoma of the lung in stage III were assessed for the expression of Bcl-2, Bcl-XL, and Bax at the mRNA and protein levels by semi-quantitative reverse transcription (RT-PCR) and immunohistochemistry. The apoptotic index (AI) was determined by the TUNEL assay. The AI ranged from <0.1 to 6.0% with a median of 1.3%. Bcl-2/Bax transcript ratio ranged from 1.5 to 4.5 and Bcl-XL/Bax from 1.3 to 4.0 indicating increased levels of anti-apoptotic molecules at the transcript levels. There was no correlation of the mRNA levels to the apoptotic index. (Wilcoxon-signed rank test.) Immunohistochemistry for proteins revealed that majority of the tumors were Bax predominated. p53 protein immunohistochemical expression was present in 66% cases. The apoptotic index correlated with Bax expression (P < 0.05; Wilcoxon-signed rank test and chi-square test) but not with Bcl-2, Bcl-XL or p53 levels. There was a positive association of p53 with Bax expression.

CONCLUSION

The results of this study indicate that in locally advanced squamous cell carcinoma of the lung, Bax protein is up regulated and determines the level of apoptosis.

Apoptosis and lung cancer: a review

It is important to understand the molecular events that contribute to drug-induced apoptosis, and how tumors evade apoptotic death. Defects in apoptosis are implicated in both tumorigenesis and drug resistance, and these defects are cause of chemotherapy failures. These studies should explain the relationship between cancer genetics and treatment sensitivity, and should enable a more rational approach to anticancer drug design and therapy. Lung cancer is a major cause of cancer deaths throughout the world. Small cell lung carcinoma (SCLC) and non-small cell lung carcinoma (NSCLC) represent the two major categories of lung cancer that differ in their sensitivity to undergo apoptosis. The role of apoptosis regulation in lung cancer with major focus on the differential sensitivities of the major subtypes is reviewed.

Injury-induced "switch" from GTP-regulated to novel GTP-independent isoform of tissue transglutaminase in the rat spinal cord

We recently found that alternative transcripts of tissue transglutaminase (tTG or TG2) were present in hippocampal brain regions of Alzheimer's disease (AD), but not in control, non-demented, age-matched brains. Since antecedent non-severe trauma has been implicated in AD and other neurodegenerative diseases, such as Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS), we were interested in whether alternative transcripts might be detected in a model of neurotrauma, controlled-contusion spinal cord injury (SCI) in the rat. Implicated in diverse roles from growth and differentiation to apoptotic cell death, only bifunctional tTG, of the nine member TG family, has dual catalytic activities: guanine trinucleotide (GTP) hydrolyzing activity (GTPase), as well as protein cross-linking. These functions imply two physiological functions: programmed cell life and death. These may have profound roles in the nervous system since studies in cultured astrocytes found tTG short (S) mRNA transcripts induced by treatment with injury-related cytokines. In the developing rat spinal cord, tTG activity is concentrated in ventral horn alpha motoneurons, but neither studies of spinal cord tTG gene expression, nor evaluation of the GTP-regulated isoforms in tissues, have been reported. We now report increased tTG protein and gene expression occurring rapidly after SCI. In parallel, novel appearance of a second, short form transcript, in addition to the normal long (L) isoform, occurs by 8 h of injury. Up-regulation of tTG message and activity following neural injury. with appearance of a truncated GTP-unregulated S form, may represent new approaches to drug targets in neurotrauma.

In vivo expression of p53 and Bcl-2 and their role in programmed cell death in premalignant and malignant lung lesions

Forty-four specimens of non-malignant and malignant human lung tissue, taken from patients with non-small cell lung cancer (NSCLC), were examined for the expression of wild-type p53, mutant p53, and bcl-2 and the occurrence of programmed cell death (apoptosis). Wild-type p53 expression peaked in peritumoral and metaplastic samples, whereas mutant p53, bcl-2 and apoptosis were first detected in metaplasia and increased with progression to carcinoma. Bcl-2 positive samples had lower levels of apoptosis than bcl-2 negative samples and was independent of wild-type or mutant p53 expression. These results suggest that the over-expression of wild-type p53 may be an early cellular response to an alteration in normal cellular homeostasis. The ensuing increase in apoptosis appears to be relatively independent of mutant or wild-type p53 expression, but does not occur in cells expressing bcl-2.

Transglutaminases in disease

Transglutaminases (TGases) are enzymes that are widely used in many biological systems for generic tissue stabilization purposes. Mutations resulting in lost activity underlie several serious disorders. In addition, new evidence documents that they may also be aberrantly activated in tissues and cells and contribute to a variety of diseases, including neurodegenerative diseases such as Alzheimer's and Huntington's diseases. In these cases, the TGases appear to be a factor in the formation of inappropriate proteinaceous aggregates that may be cytotoxic. In other cases such as celiac disease, however, TGases are involved in the generation of autoantibodies. Further, in diseases such as progressive supranuclear palsy, Huntington's, Alzheimer's and Parkinson's diseases, the aberrant activation of TGases may be caused by oxidative stress and inflammation. This review will examine the role and activation of TGases in a variety of diseases.

Adenoid cystic carcinoma: use of cell proliferation, BCL-2 expression, histologic grade, and clinical stage as predictors of clinical outcome

BACKGROUND

Although the three basic histologic growth patterns of adenoid cystic carcinomas (tubular, cribriform, and solid) provide some indication of clinical outcome, additional, perhaps superior, predictors of biologic activity are needed for patient management.

METHODS

This series is composed of 31 adenoid cystic carcinomas that presented in Linköping between 1982 and 1997. The tumors were clinically staged and histologically graded. For each case, after immunohistochemical identification, the proportion of tumor cells expressing the cell cycle markers MIB-1 and bcl-2 (as an indicator of proliferation and apoptosis, respectively) were quantified. Statistical correlation was sought between tumor stage and grade and the two cell cycle markers.

RESULTS

The proportions of cycling tumor cells in adenoid cystic carcinomas ranged from 0.3% to 55%. For patients with no evidence of disease and a follow-up of at least 5 years, the mean percent MIB-1 value was significantly lower than for those patients who were alive with local recurrence and/or metastasis or who had died from their adenoid cystic carcinoma (p =. 024). MIB-1 tumor cell positivity also correlated strongly with tumor grade (p =.053), but not with stage (p =.22). Neither clinical stage nor histologic grade correlated with the degree of bcl-2 tumor cell positivity (p =.97 and p =.49, respectively).

CONCLUSIONS

Staging and grading continue to play a vital role in the management of patients with adenoid cystic carcinoma. Furthermore, in this series of patients with adenoid cystic carcinoma, a cycling tumor cell population as measured by the MIB-1 antibody greater than 10% indicates this group as biologically more aggressive and at an increased risk for a fatal course.

Antisense bcl-2 treatment increases programmed cell death in non-small cell lung cancer cell lines

Programmed cell death (PCD) is a genetically regulated pathway that is altered in many cancers. This process is, in part, regulated by the ratio of PCD inducers (Bax) or inhibitors (Bcl-2). An abnormally high ratio of Bcl-2 to Bax prevents PCD, thus contributing to resistance to chemotherapeutic agents, many of which are capable of inducing PCD. Non-small cell lung cancer (NSCLC) cells demonstrate resistance to these PCD-inducing agents. If Bcl-2 prevents NSCLC cells from entering the PCD pathway, then reducing the amount of endogenous Bcl-2 product may allow these cells to spontaneously enter the PCD pathway. Our purpose was to determine the effects of bcl-2 antisense treatment on the levels of programmed cell death in NSCLC cells. First, we determined whether bcl-2 and bax mRNA were expressed in three morphologically distinct NSCLC cell lines: NCI-H226 (squamous), NCI-H358 (adenocarcinoma), and NCI-H596 (adenosquamous). Cells were then exposed to synthetic antisense bcl-2 oligonucleotide treatment, after which programmed cell death was determined, as evidenced by DNA fragmentation. Bcl-2 protein expression was detected immunohistochemically. All three NSCLC cell lines expressed both bcl-2 and bax mRNA and had functional PCD pathways. Synthetic antisense bcl-2 oligonucleotide treatment resulted in decreased Bcl-2 levels, reduced cell proliferation, decreased cell viability, and increased levels of spontaneous PCD. This represents the first evidence that decreasing Bcl-2 in three morphologically distinct NSCLC cell lines allows the cells to spontaneously enter a PCD pathway. It also indicates the potential therapeutic use of antisense bcl-2 in the treatment of NSCLC.