Changes In Expression Of Apoptosis-related Genes Research Articles

Integrative single-cell RNA-seq and spatial transcriptomics analyses reveal diverse apoptosis-related gene expression profiles in EGFR-mutated lung cancer

In EGFR-mutated lung cancer, the duration of response to tyrosine kinase inhibitors (TKIs) is limited by the development of acquired drug resistance. Despite the crucial role played by apoptosis-related genes in tumor cell survival, how their expression changes as resistance to EGFR-TKIs emerges remains unclear. Here, we conduct a comprehensive analysis of apoptosis-related genes, including BCL-2 and IAP family members, using single-cell RNA sequence (scRNA-seq) and spatial transcriptomics (ST). scRNA-seq of EGFR-mutated lung cancer cell lines captures changes in apoptosis-related gene expression following EGFR-TKI treatment, most notably BCL2L1 upregulation. scRNA-seq of EGFR-mutated lung cancer patient samples also reveals high BCL2L1 expression, specifically in tumor cells, while MCL1 expression is lower in tumors compared to non-tumor cells. ST analysis of specimens from transgenic mice with EGFR-driven lung cancer indicates spatial heterogeneity of tumors and corroborates scRNA-seq findings. Genetic ablation and pharmacological inhibition of BCL2L1/BCL-XL overcome or delay EGFR-TKI resistance. Overall, our findings indicate that BCL2L1/BCL-XL expression is important for tumor cell survival as EGFR-TKI resistance emerges.

Abstract 5826: Comprehensive analysis with single-cell RNA sequence and spatial transcriptomics unravels distinctive expression profile of apoptotic-related genes in EGFR-mutated lung cancer

Abstract Despite an initial marked response to targeted therapy with tyrosine kinase inhibitors (TKIs) in EGFR-mutated lung cancer, the duration of response is limited due to the inevitable development of acquired resistance. Anti- and pro-apoptotic genes play an important role in the survival of tumor cells. Currently, variations in these gene expression levels are not well characterized due to the complex interplay between the inducement of expression changes by EGFR-TKIs and the presence of inter- and intra-tumor heterogeneity. Here, a comprehensive analysis of apoptosis-related genes, including BCL-2 family members and the IAP family members, was conducted via single-cell RNA sequence (scRNA-seq) and spatial transcriptomics. scRNA-seq captured changes in apoptosis-related gene expression after EGFR-TKI treatment using different EGFR-mutated lung cancer cell lines. Notably, BCL2L1 expression increased, whereas MCL1 expression decreased after EGFR-TKI treatment. Other anti- and pro-apoptotic genes did not display consistent trends in the cell lines used. Additionally, scRNA-seq was carried out on samples collected from patients with EGFR-mutated lung cancer after the development of resistance to EGFR-TKIs in order to validate the results obtained from cell line data and to compare gene expression levels between tumor and non-tumor cells. BCL2L1 exhibited high expression specifically in tumor cells; in contrast, MCL1 expression was lower in tumor cells compared to non-tumor cells. Moreover, BAD and XIAP were highly expressed in a tumor-specific manner. To further corroborate the scRNA-seq findings and delineate the spatial heterogeneity in tumors, spatial transcriptomics was performed using EGFR-driven lung cancer transgenic mouse specimens in three conditions: prior to treatment, during therapeutic response after short-term treatment, and following acquired resistance to EGFR-TKIs. Spatial transcriptomics data demonstrated that an increased BCL2L1 expression was observed in tumor tissues and that MCL1 expression was significantly higher in tissue adjacent to tumors than in tumors. Finally, we demonstrated that genetic ablation of BCL2L1 and pharmacological inhibition of BCL2L1 overcame or delayed resistance to EGFR-TKIs in vitro and in vivo. Overall, BCL2L1 is particularly important for tumor cell survival during the emergence of drug tolerance and the development of acquired resistance to EGFR-TKIs. Citation Format: Motohiro Izumi, Masanori Fujii, Vivian Ho, Ikei S. Kobayashi, Susumu S. Kobayashi. Comprehensive analysis with single-cell RNA sequence and spatial transcriptomics unravels distinctive expression profile of apoptotic-related genes in EGFR-mutated lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5826.

Corticosteroids impair epithelial regeneration in immune-mediated intestinal damage.

Corticosteroid treatment (CST) failure is associated with poor outcomes for patients with gastrointestinal (GI) graft-versus-host disease (GVHD). CST is intended to target the immune system, but the glucocorticoid receptor (GR) is widely expressed, including within the intestines, where its effects are poorly understood. Here, we report that corticosteroids (CS) directly targeted intestinal epithelium, potentially worsening immune-mediated GI damage. CS administered to mice in vivo and intestinal organoid cultures ex vivo reduced epithelial proliferation. Following irradiation, immediate CST mitigated GI damage but delayed treatment attenuated regeneration and exacerbated damage. In a murine steroid-refractory (SR) GVHD model, CST impaired epithelial regeneration, worsened crypt loss, and reduced intestinal stem cell (ISC) frequencies. CST also exacerbated immune-mediated damage in organoid cultures with SR, GR-deficient T cells or IFN-γ. These findings correlated with CS-dependent changes in apoptosis-related gene expression and STAT3-related epithelial proliferation. Conversely, IL-22 administration enhanced STAT3 activity and overcame CS-mediated attenuation of regeneration, reducing crypt loss and promoting ISC expansion in steroid-treated mice with GVHD. Therefore, CST has the potential to exacerbate GI damage if it fails to control the damage-inducing immune response, but this risk may be countered by strategies augmenting epithelial regeneration, thus providing a rationale for clinical approaches combining such tissue-targeted therapies with immunosuppression.

Role of Mitochondrial Dysfunction in the Pathogenesis of Cisplatin-Induced Myotube Atrophy.

Muscle atrophy is commonly observed during cisplatin chemotherapy, leading to a reduced QOL in cancer patients. Reduced skeletal muscle mass caused by cisplatin treatment results from the activation of ubiquitin ligases-Atrogin-1 and MuRF1, but the precise mechanisms are poorly understood. In this study, we investigated the possible involvement of mitochondrial dysfunction, including reactive oxygen species (ROS) generation and ATP production, in cisplatin-induced muscle atrophy. Skeletal C2C12 myotubes were treated with cisplatin, and gene and protein expression were evaluated. Mitochondrial mass, membrane potential, and ROS levels were measured using fluorescent dyes. Mitochondrial respiratory function, ATP production rates, and glycolytic capacity were also analyzed using an extracellular flux analyzer. Metabolomic analyses were performed using gas chromatography-tandem mass spectrometry. Cisplatin treatment reduced myosin heavy chain expression by activating the ubiquitin-proteasome system. Increased ROS production was observed after cisplatin treatment, followed by significant changes in apoptosis-related gene expression and decrease in mitochondrial mass, membrane potential, respiration, and ATP production. Glycolytic capacity and tricarboxylic acid (TCA) cycle metabolite levels were reduced with cisplatin treatment. Mitochondria-targeted antioxidant mitoquinone mesylate prevented up-regulation of Atrogin-1 gene expression and restored myosin heavy chain levels, accompanied by a decrease in ROS generation, but not mitochondrial ATP production. We concluded that cisplatin-induced myotube atrophy was associated with mitochondrial dysfunction. Reducing ROS generation, rather than promoting ATP production, could be a useful therapeutic strategy for preventing cisplatin-induced muscle atrophy.

Tetrandrine and arsenic trioxide synergistically inhibit proliferation of HCC1937 triple negative breast cancer cells

ObjectiveTo evaluate the effects of tetrandrine plus arsenic trioxide on HCC1937 cells, a triple negative breast cancer cell line, and to explore possible mechanisms. MethodsThe 3-(4,5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide method was used to compare the antiproliferative effects of tetrandrine, arsenic trioxide alone and tetrandrine plus arsenic trioxide on HCC1937 cells. The median-effect principle (Chou-Talalay combination index method) was used to examine the interaction between the two drugs. Flow cytometry was used to evaluate effects of treatment with tetrandrine, arsenic trioxide or the combination of both on HCC1937 cell apoptosis. Real-time polymerase chain reaction and western blotting were performed to evaluate changes in apoptosis-related gene expression and protein levels. ResultsTetrandrine and arsenic trioxide each inhibited HCC1937 cell proliferation in a dose-dependent manner. The cell inhibition rate of HCC1937 cells treated with a combination of tetrandrine and arsenic trioxide was significantly higher than with either compound alone. The two drugs produced a synergistic effect when the inhibition rate was 20%-40%. Flow cytometry results showed that treatment with the two drugs increased the proportion of apoptotic cells. In the combination treated group, caspase-3 activation and PARP cleavage were significantly higher than in the other groups. Moreover, Bcl-2 and survivin expression were decreased, whereas that of both Bid and Bax was increased. ConclusionThese findings demonstrated that tetrandrine plus arsenic trioxide had synergistic efficacy on induction of apoptosis in HCC1937 cells.

Changes in apoptosis-related gene expression and cytokine release in breast cancer cells treated with CpG-loaded magnetic PAMAM nanoparticles

CpG-oligodeoxynucleotide (CpG-ODN) can function as an immune adjuvant. Previously, we showed that stimulation of breast cancer cells with CpG-ODN conjugated with PAMAM dendrimer-coated magnetic nanoparticles (DcMNPs) has induced apoptosis. The aim of the current study was to evaluate the expression levels of some apoptosis-regulating genes in several human breast cancer cells treated with CpG/DcMNPs. Treated MDA-MB231 cells showed an increase in Noxa and Bax gene expression levels, whereas the expression level of Survivin decreased. Similarly, Noxa gene was overexpressed in treated MCF7 cells. In treated SKBR3 cells, a decline in the c-Flip mRNA level was determined. Furthermore, release of cytokines, IL-6, IL-10, and TNF-α, was determined in cell culture supernatants. CpG/DcMNP treatment leads to an increase in the release of IL-6 in MDA-MB231 and SKBR3 cells, whereas release of IL-10 and TNF-α did not change significantly. It is indicated that CpG-ODN may show its cytotoxic effect by regulating the expression of apoptosis-related genes and the release of cytokine in breast cancer cells.

Apoptosis-related BCL2-family Members: Key Players in Chemotherapy

Classical chemotherapeutic agents such as mitotic inhibitors (spindle poisons), alkylating agents, antimetabolites, topoisomerase inhibitors, and anthracenediones (anthracyclines) inhibit DNA synthesis and mitosis, thereby killing or impeding the proliferation of rapidly dividing cells. During the last decade, targeted therapy has gained advantage over conventional treatment regimens, as it is more effective against cancer and also much less harmful to normal cells, thus minimizing the side-effects of chemotherapy. This type of treatment blocks the proliferation of cancer cells by inhibiting the function of specific targeted molecules needed for tumor growth and metastasis. Targeted therapy agents include monoclonal antibodies and small-molecule inhibitors, which most commonly target receptor and/or non-receptor tyrosine kinases. Most members of the BCL2 apoptosis-related family regulate cellular fate as a response to antineoplastic agents. Modulations at the mRNA and protein levels of these genes are usually associated with sensitivity or resistance of various types of cancer cells to chemotherapeutic drugs. Moreover, alterations in expression of BCL2-family members, induced by anticancer drug treatment, can trigger or simply facilitate apoptosis. In this review, we summarize information about changes in apoptosis-related gene expression caused directly or indirectly by antineoplastic agents, as well as about the impact of BCL2-family members on the chemosensitivity or chemoresistance of cancer cells.

Changes in Apoptosis-related Gene Expression Induced by Repression of FGFR1 by RNA Interference in Embryonic Fibroblasts and Cancerous Cells from Chicken

ABSTRACT Fibroblast growth factor receptor 1 ( FGFR1 ) plays roles in angiogenesis, wound healing, and embryonic development via the regulation of cell proliferation, differentiation, and survival. It is well known that ectopic expression of FGFR1 is associated with cancer development. To characterize the function of FGFR1 in the normal and cancer cell lines DF-1 and DT40, respectively, we performed FGFR1 knockdown by RNA interference. In the DT40 cells, FGFR1 knockdown induced upregulation of FGFR2 and FGFR3 expression, downregulation of pro-apoptosis-related genes, and upregulation of anti-apoptosis-related genes. However, in DF-1 cells, FGFR1 knockdown induced upregulation of pro-apoptosis-related genes and downregulation of anti-apoptosis-related genes. Our data suggest that repression of FGFR1 induced upregulation of other FGF receptors and anti-apoptosis-related genes in cancer cells and pro-apoptosis-related genes in normal cells.( Key words : RNA interference, FGFR1 , Apoptosis, DT40, DF1)

Characterization of ochratoxin A-induced apoptosis in primary rat hepatocytes

The main target organ of the mycotoxin ochratoxin A (OTA) in mammals is the kidney but OTA has also been shown to be hepatotoxic in rats and to induce tumors in mouse liver. Even at very low concentrations, OTA causes perturbations of cellular signaling pathways as well as enhanced apoptosis. OTA has been extensively studied in kidney cell systems. Since this substance also affects liver health, we focused our work on apoptosis-related events induced by OTA in primary rat hepatocytes. We performed pathway-specific polymerase chain reaction arrays to assess the expression of genes involved in apoptosis. Treatment with 1 microM OTA for 24 h caused marked changes in apoptosis-related gene expression. Genes as apaf1, bad, caspase 7, polb (DNA polymerase beta, performs base excision repair), and p53, which are marker genes for DNA damage, were upregulated. FAS and faslg were also markedly induced by treatment with OTA. Treatment of hepatocytes with OTA led to a concentration-dependent inhibition of protein biosynthesis. Apoptosis-inducing factor was released from mitochondria following OTA treatment; the mycotoxin induced the activity of caspases 8, 9, and 3/7 and caused chromatin condensation and fragmentation. Caspase inhibition led to a significant but not complete reduction of OTA-induced apoptosis. Our data suggest that not only OTA leads to p53-dependent apoptosis in rat hepatocytes but it also hints to other mechanisms, independent of caspase activation or protein biosynthesis, being involved.

Study on the bone marrow mesenchymal stem cells induced drug resistance in the U937 cells and its mechanism

The hematopoietic microenvironment (HM) plays a critical role in malignant cell growth, patient survival, and response to chemotherapy in hematologic malignancies. However, mechanisms associated with this environmental influence remain unclear. In this study, we investigated the role of bone marrow derived mesenchymal stem cells (MSCs) in U937 cell line, to find out the relations between leukemia drug resistance and the MSCs. U937 cells were cultured in suspension or grew adherently with MSCs. The cell growth curve was drawn and the cell cycle was measured by flow cytometry. Apoptosis and sensitivity of U937 to daunoblastina (DNR) were quantified by DNA ladder detection and trypan blue exclusion assays, respectively. The gene expression profile chip technology was used to determine and analyze the changes in apoptosis-related gene expression after adherent culture and the expression of MDR1 mRNA was assessed by reverse transcriptional polymerase chain reaction (RT-PCR) at the same time. In the adherent culture, the proliferation of the U937 cells was inhibited, the G0/G1 phase cells increased (F = 64.9726, P < 0.0001), G2/M phase cells were decreased (F = 98.1361, P < 0.0001) and the natural apoptosis rate was decreased (F = 24.0866, P < 0.0001) compared with those in the suspended culture. U937 cell viability was enhanced and cell apoptosis was blocked during DNR treatment in adherent culture with MSCs. Thirty-nine differently expressed genes were screened from the 487 apoptosis related genes in the adherent culture U937 cells. Among the 37 upregulated genes, Bcl-XL was upregulated most significantly. Two genes were downregulated. Adherent culture did not induce MDR1 mRNA expression in U937 cells. MSCs play a role in modulating the proliferation of U937 cells and response of U937 cells to DNR, and Bcl-XL apoptosis-inhibiting gene may be most important in determining the sensitivity of leukemic cells to treatment, which is not related to MDR1.

Regulation of polymorphonuclear leukocyte apoptosis: role of lung endothelium-epithelium bilayer transmigration.

Delayed polymorphonuclear leukocyte (PMN) apoptosis exacerbates acute lung injury. To reach the alveolar spaces, PMNs must migrate across both pulmonary endothelial and epithelial cell layers. We hypothesized that transmigration across the endothelium-epithelium bilayer suppresses PMN apoptosis and sought to elucidate the underlying mechanisms. PMNs freshly isolated from normal volunteers were allowed to migrate across polycarbonate membranes alone or membranes coated with a bilayer of human lung endothelial and epithelial cells. After migration toward different chemoattractants (IL-8, formyl-Met-Leu-Phe, or leukotriene B(4)), PMN apoptosis and caspase activities were assessed by annexin V, histology, and enzymatic assays, respectively. Messenger RNA and specific protein expression in three receptor ligand-mediated, apoptosis-inducing pathways (Fas, TNF-alpha, and TNF-related apoptosis-inducing ligand) were further examined by gene array, RT-PCR, flow cytometry, and Western blot analyses. The data demonstrated that transbilayer migration suppressed PMN apoptosis, and this effect was not chemoattractant type specific. Kinetic analyses further showed that the delay of apoptosis was sustained to at least 18 h. Transbilayer migration caused significant decreases in caspase (-3, -8, and -9) activities. The changes in apoptosis-related gene expression support the survival role of transbilayer migration. Furthermore, the reduced apoptosis was correlated with downregulation of Fas ligand and TNF receptor 1 expression. Our data reveal that migration across a lung endothelium-epithelium bilayer suppresses PMN apoptosis. The decreased activity and/or expression of proapoptotic proteins may provide possible targets for the regulation of inappropriate delay in PMN apoptosis during lung inflammation and injury.