Killing Two Cells with One Stone: Pharmacologic BCL-2 Family Targeting for Cancer Cell Death and Immune Modulation

Influence of Nanocurcumin and Photodynamic Therapy Using Nanocurcumin in Treatment of Rat Tongue Oral Squamous Cell Carcinoma Through Histological Examination and Gene Expression of BCL2 and Caspase-3

Background

Oral squamous cell carcinoma (OSCC) is the sixth most common mouth cancer in the world. The aim of the present study is comparing the effects of using Nanocurcumin, and photodynamic therapy (PDT), alone or together in treatment of OSCC in rats.

Methods

Forty Wister male rats were divided into Control (group 1), 650 nm diode Laser only (group 2), Nanocurcumin alone (group 3), and PDT with a combination of laser with Nanocurcumin (group 4). Then, OSCC in the tongue induced by dimethylbenz anthracene (DMBA). The treatments were evaluated clinically, histopathologically, and immunohistochemically through BCL2 and Caspase-3 genes expression.

Results

Positive control with OSCC displayed significant weight loss, while PDT group gained more than nanocurcumin treated groups as well as laser groups comparing with control positive group. The histological examination of the tongue in PDT group showed improvement. In laser group, there were partial loss of surface epithelium with various ulcers and dysplasia and partial improvement by this type of treatment. The tongue in the positive control group showed ulcer in the dorsum surface with inflammatory cells, hyperplasia of the mucosa membrane around the ulcer (acanthosis) with increase of dentition, vacuolar degeneration of prickle cell layer and increase mitotic activity of basal cell layer together with dermal proliferation.

Conclusion

Under the condition of the present study, PDT using nanocurcumin photosensitizer was effective in the treatment of OSCC regarding clinical, histological and gene expression of BCL2 and Caspase-3.

Small-Molecule PROTACs for Cancer Immunotherapy

Unsatisfactory physicochemical properties of macromolecular drugs seriously hinder their application in tumor immunotherapy. However, these problems can be effectively solved by small-molecule compounds. In the promising field of small-molecule drug development, proteolysis targeting chimera (PROTAC) offers a novel mode of action in the interactions between small molecules and therapeutic targets (mainly proteins). This revolutionary technology has shown considerable impact on several proteins related to tumor survival but is rarely exploited in proteins associated with immuno-oncology up until now. This review attempts to comprehensively summarize the well-studied and less-developed immunological targets available for PROTAC technology, as well as some targets to be explored, aiming to provide more options and opportunities for the development of small-molecule-based tumor immunotherapy. In addition, some novel directions that can magnify and broaden the protein degradation efficiency are mentioned to improve PROTAC design in the future.

Harnessing the Therapeutic Potential of Biomacromolecules through Intracellular Delivery of Nucleic Acids, Peptides, and Proteins

Biomacromolecules have long been at the leading edge of academic and pharmaceutical drug development and clinical translation. With the clinical advances of new therapeutics, such as monoclonal antibodies and nucleic acids, the array of medical applications of biomacromolecules has broadened considerably. A major on-going effort is to expand therapeutic targets within intracellular locations. Owing to their large sizes, abundant charges, and hydrogen-bond donors and acceptors, advanced delivery technologies are required to deliver biomacromolecules effectively inside cells. In this review, strategies used for the intracellular delivery of three major forms of biomacromolecules: nucleic acids, proteins, and peptides, are highlighted. An emphasis is placed on synthetic delivery approaches and the major hurdles needed to be overcome for their ultimate clinical translation.

Protein interaction networks provide insight into fetal origins of chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a leading cause of death in adults that may have origins in early lung development. It is a complex disease, influenced by multiple factors including genetic variants and environmental factors. Maternal smoking during pregnancy may influence the risk for diseases during adulthood, potentially through epigenetic modifications including methylation.

METHODS

In this work, we explore the fetal origins of COPD by utilizing lung DNA methylation marks associated with in utero smoke (IUS) exposure, and evaluate the network relationships between methylomic and transcriptomic signatures associated with adult lung tissue from former smokers with and without COPD. To identify potential pathobiological mechanisms that may link fetal lung, smoke exposure and adult lung disease, we study the interactions (physical and functional) of identified genes using protein-protein interaction networks.

RESULTS

We build IUS-exposure and COPD modules, which identify connected subnetworks linking fetal lung smoke exposure to adult COPD. Studying the relationships and connectivity among the different modules for fetal smoke exposure and adult COPD, we identify enriched pathways, including the AGE-RAGE and focal adhesion pathways.

CONCLUSIONS

The modules identified in our analysis add new and potentially important insights to understanding the early life molecular perturbations related to the pathogenesis of COPD. We identify AGE-RAGE and focal adhesion as two biologically plausible pathways that may reveal lung developmental contributions to COPD. We were not only able to identify meaningful modules but were also able to study interconnections between smoke exposure and lung disease, augmenting our knowledge about the fetal origins of COPD.

A systems genetics approach delineates the role of Bcl2 in leukemia pathogenesis

Leukemia is a group of malignancies of the blood forming tissues, and is characterized by the uncontrolled proliferation of blood cells. In the United States, it accounts for approximately 3.5% and 4% of all cancer-related incidences and mortalities, respectively. The current study aimed to explore the role of Bcl2 and associated genes in leukemia pathogenesis using a systems genetics approach. The transcriptome data from BXD Recombinant Inbred (RI) mice was analyzed to identify the expression of Bcl2 in myeloid cells. eQTL mapping was performed to select the potential chromosomal region and subsequently identify the candidate gene modulating the expression of Bcl2. Furthermore, gene enrichment and protein-protein interaction (PPI) analyses of the Bcl2-coexpressed genes were performed to demonstrate the role of Bcl2 in leukemia pathogenesis. The Bcl2-coexpressed genes were found to be enriched in various hematopoietic system related functions, and multiple pathways related to signaling, immune response, and cancer. The PPI network analysis demonstrated direct interaction of hematopoietic function related genes, such as Bag3, Bak1, Bcl2l11, Bmf, Mapk9, Myc, Ppp2r5c, and Ppp3ca with Bcl2. The eQTL mapping identified a 4.5 Mb genomic region on chromosome 11, potentially regulating the expression of Bcl2. A multi-criteria filtering process identified Top2a, among the genes located in the mapped locus, as the best candidate upstream regulator for Bcl2 expression variation. Hence, the current study provides better insights into the role of Bcl2 in leukemia pathogenesis and demonstrates the significance of our approach in gaining new knowledge on leukemia. Furthermore, our findings from the PPI network analysis and eQTL mapping provide supporting evidence of leukemia-associated genes, which can be further explored for their functional importance in leukemia. DATA AVAILABILITY: The myeloid cell transcriptomic data of the BXD mice used in this study can be accessed through our GeneNetwork (http://www.genenetwork.org) with the accession number of GN144.

Bim Expression Promotes the Clearance of Mononuclear Phagocytes during Choroidal Neovascularization, Mitigating Scar Formation in Mice

Inflammation is increasingly recognized as an important modulator in the pathogenesis of neovascular age-related macular degeneration (nAMD). Although significant progress has been made in delineating the pathways that contribute to the recruitment of inflammatory cells and their contribution to nAMD, we know little about what drives the resolution of these inflammatory responses. Gaining a better understanding of how immune cells are cleared in the choroid will give a novel insight into how sustained inflammation could influence the pathogenesis of nAMD. The pro-apoptotic Bcl-2 family member Bim is a master regulator of immune cell homeostasis. In its absence, immune cell lifespan and numbers increase. Most therapeutic regimes that squelch inflammation do so by enhancing immune cell apoptosis through enhanced Bim expression and activity. To test the hypothesis that Bim expression tempers inflammation during the pathogenesis of nAMD, we used the mouse laser-induced choroidal neovascularization (CNV) model in which inflammation acts as a facilitator of CNV. Here, we showed minimal to no change in the recruitment of F4/80-, CD80-, CD11b-, and Iba1-positive myeloid-derived mononuclear phagocytes to the site of laser photocoagulation in the absence of Bim expression. However, the resolution of these cells from the choroid of Bim-deficient (Bim -/-) mice was significantly diminished following laser photocoagulation. With time, we noted increased scar formation, demonstrated by collagen I staining, in Bim -/- mice with no change in the resolution of neovascularization compared to wild-type littermates. We also noted that mice lacking Bim expression in mononuclear phagocytes (BimFlox/Flox; Lyz2-Cre (BimMP) mice) had delayed resolution of F4/80-, CD80-, CD11b-, and Iba1-positive cells, while those lacking Bim expression in endothelial cells (BimFlox/Flox; Cad5-Cre (BimEC) mice) had delayed resolution of only CD11b- and Iba1-positive cells. Both BimMP and BimEC mice demonstrated increased scar formation, albeit to differing degrees. Thus, our studies show that resolving inflammation plays an important role in moderating scar formation in nAMD, and it is impacted by Bim expression in both the endothelium and mononuclear phagocyte lineages.

Venetoclax imparts distinct cell death sensitivity and adaptivity patterns in T cells

BH3 mimetics are increasingly used as anti-cancer therapeutics either alone or in conjunction with other chemotherapies. However, mounting evidence has also demonstrated that BH3 mimetics modulate varied amounts of apoptotic signaling in healthy immune populations. In order to maximize their clinical potential, it will be essential to understand how BH3 mimetics affect discrete immune populations and to determine how BH3 mimetic pressure causes immune system adaptation. Here we focus on the BCL-2 specific inhibitor venetoclax (ABT-199) and its effects following short-term and long-term BCL-2 blockade on T cell subsets. Seven day "short-term" ex vivo and in vivo BCL-2 inhibition led to divergent cell death sensitivity patterns in CD8⁺ T cells, CD4⁺ T cells, and Tregs resulting in shifting of global T cell populations towards a more memory T cell state with increased expression of BCL-2, BCL-X_L, and MCL-1. However, twenty-eight day "long-term" BCL-2 blockade following T cell-depleted bone marrow transplantation did not lead to changes in the global T cell landscape. Despite the lack of changes in T cell proportions, animals treated with venetoclax developed CD8⁺ and CD4⁺ T cells with high levels of BCL-2 and were more resistant to apoptotic stimuli following expansion post-transplant. Further, we demonstrate through RNA profiling that T cells adapt while under BCL-2 blockade post-transplant and develop a more activated genotype. Taken together, these data emphasize the importance of evaluating how BH3 mimetics affect the immune system in different treatment modalities and disease contexts and suggest that venetoclax should be further explored as an immunomodulatory compound.

Interactions of multidomain pro-apoptotic and anti-apoptotic proteins in cancer cell death

Cancer is a global public health concern that is characterized by the uncontrolled growth of tumor cells. It is regarded as the subsequent cause of death after cardiovascular disease. The most common types of cancer include breast, colorectal, lung, and prostate. The risk factors attributed to the development of common types of cancer are tobacco smoking, excessive alcohol consumption, dietary factors, ultraviolet radiation (UV), and lack of physical activities. Two major cellular apoptotic pathways targeted in cancer therapies are intrinsic and extrinsic. These two pathways are regulated by different types of proteins, the multidomain pro-apoptotic proteins (Bak, Bax, and Bok), BH3-only pro-apoptotic proteins (Bid, Bim, Bad, Noxa, and Puma), and the anti-apoptotic proteins (Mcl-1, Bfl-1, Bcl-XL, Bcl-2, Bcl-w, and Bcl-B). Other significant molecules/factors that are known to execute cellular apoptotic pathways include bioactive compounds, and reactive oxygen species (ROS). Proteolytic caspases are known to play a vital role in the initiation of apoptotic activities in cancerous cells. Based on their functions, they are categorized into initiators and executioners. Nanotechnology has produced novel outcomes in modern medicine. The green synthesis of nanoparticles has demonstrated prospective improvements in cancer therapies in combination with the existing therapies including photodynamic therapy. This review aims at highlighting the association between pro-apoptotic and anti-apoptotic proteins, and their significance in cancer therapy.

Potentiating Therapeutic Effects of Epidermal Growth Factor Receptor Inhibition in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a subset of breast cancer with aggressive characteristics and few therapeutic options. The lack of an appropriate therapeutic target is a challenging issue in treating TNBC. Although a high level expression of epidermal growth factor receptor (EGFR) has been associated with a poor prognosis among patients with TNBC, targeted anti-EGFR therapies have demonstrated limited efficacy for TNBC treatment in both clinical and preclinical settings. However, with the advantage of a number of clinically approved EGFR inhibitors (EGFRis), combination strategies have been explored as a promising approach to overcome the intrinsic resistance of TNBC to EGFRis. In this review, we analyzed the literature on the combination of EGFRis with other molecularly targeted therapeutics or conventional chemotherapeutics to understand the current knowledge and to provide potential therapeutic options for TNBC treatment.

Novel Hybrid CHC from β-carboline and N-Hydroxyacrylamide Overcomes Drug-Resistant Hepatocellular Carcinoma by Promoting Apoptosis, DNA Damage, and Cell Cycle Arrest

A novel hybrid CHC was designed and synthesized by conjugating β-carboline with an important active fragment N-hydroxyacrylamide of histone deacetylase (HDAC) inhibitor by an amide linkage to enhance antitumor efficacy/potency or even block drug resistance. CHC displayed high antiproliferative effects against drug-sensitive SUMM-7721, Bel7402, Huh7, and HCT116 cells and drug-resistant Bel7402/5FU cells with IC₅₀ values ranging from 1.84 to 3.27 μM, which were two-to four-fold lower than those of FDA-approved HDAC inhibitor SAHA. However, CHC had relatively weak effect on non-tumor hepatic LO2 cells. Furthermore, CHC exhibited selective HDAC1/6 inhibitory effects and simultaneously augmented the acetylated histone H3/H4 and α-tubulin, which may make a great contribution to their antiproliferative effects. In addition, CHC also electrostatically interacted with CT-DNA, exerted remarkable cellular apoptosis by regulating the expression of apoptosis-related proteins and DNA damage proteins in Bel7402/5FU cells, and significantly accumulated cancer cells at the G2/M phase of the cell cycle by suppressing CDK1 and cyclin B protein with greater potency than SAHA-treated groups. Finally, CHC displayed strong inhibitory potency to drug-resistant hepatic tumors in mice. Our designed and synthetic hybrid CHC could be further developed as a significant and selective anticancer agent to potentially treat drug-resistant hepatocellular carcinoma.

Loss of BIM in T cells results in BCL-2 family BH3-member compensation but incomplete cell death sensitivity normalization

BIM is the master BH3-only BCL-2 family regulator of lymphocyte survival. To understand how long-term loss of BIM affects apoptotic resistance in T cells we studied animals with T cell-specific deletion of Bim. Unlike CD19^CREBim^fl/fl animals, LCK^CREBim^fl/fl mice have pronounced early lymphocytosis followed by normalization of lymphocyte counts over time. This normalization occurred in mature T cells, as thymocyte development and apoptotic sensitivity remained abnormal in LCK^CREBim^fl/fl mice. T cells from aged mice experienced normalization of their absolute cell numbers and responses against various apoptotic stimuli. mRNA expression levels of BCL-2 family proteins in CD4⁺ and CD8⁺ T cells from young and old mice revealed upregulation of several BH3-only proteins, including Puma, Noxa, and Bmf. Despite upregulation of various BH3 proteins, there were no differences in anti-apoptotic BCL-2 protein dependency in these cells. However, T cells had continued resistance to direct BIM BH3-induced mitochondrial depolarization. This study further highlights the importance of BIM in cell death maintenance in T cells and provides new insight into the dynamism underlying BH3-only regulation of T cell homeostasis versus induced cell death and suggests that CD4⁺ and CD8⁺ T cells compensate differently in response to loss of Bim.

Flow Cytometry-Based Detection and Analysis of BCL-2 Family Proteins and Mitochondrial Outer Membrane Permeabilization (MOMP)

The BCL-2 family of proteins orchestrates a complex signaling network that governs the balance between cellular survival and death. A comprehensive understanding of the mechanistic interactions between these proteins continues to evolve in normal and malignant cells. The functional variation by individual BCL-2 proteins in different cell types has driven clinical therapeutic development in targeting individual BCL-2 members with the goal of fine-tuning cell death in diseased cells. Given the importance of understanding and validating the effect of activating or inhibiting BCL-2 protein interactions in individual cells, the methods used to measure apoptotic cell death have undergone increased scrutiny. Here, we describe two in vitro flow cytometry-based methods that are useful in measuring BCL-2 proteins and mitochondrial-based cell death in complex cell populations.

Comparing the effects of different cell death programs in tumor progression and immunotherapy

Our conception of programmed cell death has expanded beyond apoptosis to encompass additional forms of cell suicide, including necroptosis and pyroptosis; these cell death modalities are notable for their diverse and emerging roles in engaging the immune system. Concurrently, treatments that activate the immune system to combat cancer have achieved remarkable success in the clinic. These two scientific narratives converge to provide new perspectives on the role of programmed cell death in cancer therapy. This review focuses on our current understanding of the relationship between apoptosis and antitumor immune responses and the emerging evidence that induction of alternate death pathways such as necroptosis could improve therapeutic outcomes.

BH3 mimetics induce apoptosis independent of DRP-1 in melanoma

Despite the recent advancement in treating melanoma, options are still limited for patients without BRAF mutations or in relapse from current treatments. BH3 mimetics against members of the BCL-2 family have gained excitement with the recent success in hematological malignancies. However, single drug BH3 mimetic therapy in melanoma has limited effectiveness due to escape by the anti-apoptotic protein MCL-1 and/or survival of melanoma-initiating cells (MICs). We tested the efficacy of the BH3 mimetic combination of A-1210477 (an MCL-1 inhibitor) and ABT-263 (a BCL-2/BCL-XL/BCL-W inhibitor) in killing melanoma, especially MICs. We also sought to better define Dynamin-Related Protein 1 (DRP-1)'s role in melanoma; DRP-1 is known to interact with members of the BCL-2 family and is a possible therapeutic target for melanoma treatment. We used multiple assays (cell viability, apoptosis, bright field, immunoblot, and sphere formation), as well as the CRISPR/Cas9 genome-editing techniques. For clinical relevance, we employed patient samples of different mutation status, including some relapsed from current treatments such as anti-PD-1 immunotherapy. We found the BH3 mimetic combination kill both the MICs and non-MICs (bulk of melanoma) in all cell lines and patient samples irrespective of the mutation status or relapsed state (p < 0.05). Unexpectedly, the major pro-apoptotic proteins, NOXA and BIM, are not necessary for the combination-induced cell death. Furthermore, the combination impedes the activation of DRP-1, and inhibition of DRP-1 further enhances apoptosis (p < 0.05). DRP-1 effects in melanoma differ from those seen in other cancer cells. These results provide new insights into BCL-2 family's regulation of the apoptotic pathway in melanoma, and suggest that inhibiting the major anti-apoptotic proteins is sufficient to induce cell death even without involvement from major pro-apoptotic proteins. Importantly, our study also indicates that DRP-1 inhibition is a promising adjuvant for BH3 mimetics in melanoma treatment.

Butein Inhibited In Vitro Hexokinase-2-Mediated Tumor Glycolysis in Hepatocellular Carcinoma by Blocking Epidermal Growth Factor Receptor (EGFR)

BACKGROUND Anaerobic glycolysis is an important physiological process of all cancer cells. Butein has been reported to demonstrate substantial antitumor activities in various cancers. However, the effect of butein on tumor glycolysis remains unclear. In this study, the effect of butein on tumor glycolysis and the underlying mechanism were investigated in hepatocellular carcinoma (HCC). MATERIAL AND METHODS Cell proliferation assay and anchorage-independent growth assay were carried out to evaluate the antitumor activities of butein in vitro. The effect of butein on tumor glycolysis was determined by examining the changes in glucose uptake and lactate production. Hexokinase-2 (HK-2) expression in HCC cells upon butein treatment was analyzed by Western blotting. The activity of butein on EGFR signaling pathway was studied and its potency in EGFR exogenous overexpression cells was investigated. RESULTS After butein treatment, HCC cell proliferation was significantly inhibited (91.4% in Hep3B and 88.2% in Huh-7 at 80 μM, p<0.001). Moreover, the number of colonies formed in the agar was substantially decreased (93.8% in Hep3B and 72.3% in Huh-7 at 80 μM, p<0.001). With the suppression of HK-2 expression, glucose consumption in Hep3B and Huh-7 cells decreased by 48.4% and 56.3%, respectively (p<0.01), and the lactate production also was reduced accordingly (39.5% in Hep3B and 48.6% in Huh-7, p<0.01). Mechanism investigations demonstrated that butein dose-dependently blocked the activation of the EGFR signaling pathway in HCC cells. In EGFR exogenous overexpression cells, the glycolysis suppression exerted by butein was substantially attenuated. CONCLUSIONS Butein has a substantial inhibitory effect on tumor glycolysis in HCC cells, and the glycolysis suppression exerted by butein is closely related to its effect on the EGFR signaling pathway.