The Discovery of a Novel Antimetastatic Bcl3 Inhibitor

Enhancing cell death in B-cell malignancies through targeted inhibition of Bcl-3

The t(14;19)(q32;q13) is a rare recurring translocation found in B-cell lymphoproliferative malignancies, involving the Bcl-3 gene. This chromosomal translocation is often found in patients under the age of 50 and causes a more progressive disease. The Bcl-3 gene encodes a protein belonging to the IκB family of proteins, which tightly regulates NFκB signaling by acting as an activator or repressor of transcription. Previously, we developed a second-generation Bcl-3 inhibitor that could directly interfere with Bcl-3 signaling pathway, resulting in reduced melanoma cell proliferation, invasion, and migration. The present study aimed to investigate the effect of a Bcl-3 inhibitor on B-cell lymphoma and leukemia cells. It was found that treatment of cells with this inhibitor caused a decrease in cell proliferation and cell survival. Furthermore, Bcl-3 inhibition in B-cell malignant cells resulted in the loss of mitochondrial membrane potential and functionality, as well as the increased expression of cleaved caspase 3, indicating that cell death occurs through the intrinsic apoptotic pathway. This observation is further supported by reduced expression of cIAP1 protein 1 (cIAP1) upon treatment of cancer cells. Given the current lack of clinical advancements targeting Bcl-3 in oncology, this opens a novel avenue for the development and investigation of highly specific therapeutic interventions against B-cell malignancies.

Engineering an Organic Nanoplatform for Augmented Pyroeletroimmunotherapy

Photothermal immunotherapy has shown great promise in the treatment of tumor metastasis. However, the thermal resistance of tumor cells substantially compromises the treatment effect of photothermal immunotherapy. Herein, a high-performance organic pyroelectric nanoplatform, tBu-TPAD-BF2 nanoparticles (NPs), is rationally engineered for the effective pyroelectroimmunotherapy of tumor metastasis. Biocompatible tBu-TPAD-BF2 NPs with excellent pyroelectric and photothermal conversion properties are constructed by assembling organic, low-bandgap pyroelectric molecules with amphiphilic polymers. After internalization by tumor cells, treatment with tBu-TPAD-BF2 NPs causes an apparent temperature elevation upon near-infrared (NIR) laser irradiation, inducing potent immunogenic cell death (ICD). Additionally, the temperature variations under alternating NIR laser irradiation facilitate reactive oxygen species production for pyroelectric therapy, thus promoting ICD activation and lowering thermal resistance. Importantly, in vivo assessments illustrate that tBu-TPAD-BF2 NPs in combination with NIR laser exposure notably inhibit primary and distant tumor proliferation and prominently retarded lung metastasis. RNA profiling reveals that treatment with tBu-TPAD-BF2 NPs markedly suppresses metastasis under NIR laser illumination by downregulating metastasis-related genes and upregulating immune response-associated pathways. Therefore, this study provides a strategy for designing high-performance pyroelectric nanoplatforms to effectively cure tumor metastasis, thereby overcoming the inherent shortcomings of photothermal immunotherapy.

The atypical IκB family member Bcl3 determines differentiation and fate of intestinal RORγt+ regulatory T-cell subsets

Peripherally-induced regulatory T cells (pTregs) expressing the retinoic acid receptor-related orphan-receptor gamma t (RORγt) are indispensable for intestinal immune homeostasis. Nuclear factor kappa family members regulate the differentiation of thymic Tregs and promote their survival in the periphery. However, the Treg intrinsic molecular mechanisms controlling the size of the pTregs in the intestine and associated lymphoid organs remain unclear. Here, we provide direct evidence that B-cell lymphoma 3 (Bcl3) limits the development of pTregs in a T cell-intrinsic manner. Moreover, the absence of Bcl3 allowed for the formation of an unusual intestinal Treg population co-expressing the transcription factors Helios and RORγt. The expanded RORγt+ Treg populations in the absence of Bcl3 displayed an activated phenotype and secreted high levels of the anti-inflammatory cytokines interleukin (IL)-10 and transforming growth factor beta. They were fully capable of suppressing effector T cells in a transfer colitis model despite an intrinsic bias to trans-differentiate toward T helper 17-like cells. Finally, we provide a Bcl3-dependent gene signature in pTregs including altered responsiveness to the cytokines IL-2, IL-6, and tumor necrosis factor alpha. Our results demonstrate that Bcl3 acts as a molecular switch to limit the expansion of different intestinal Treg subsets and may thus serve as a novel therapeutic target for inflammatory bowel disease by restoring intestinal immune tolerance.

IFNγ-Induced Bcl3, PD-L1 and IL-8 Signaling in Ovarian Cancer: Mechanisms and Clinical Significance

IFNγ, a pleiotropic cytokine produced not only by activated lymphocytes but also in response to cancer immunotherapies, has both antitumor and tumor-promoting functions. In ovarian cancer (OC) cells, the tumor-promoting functions of IFNγ are mediated by IFNγ-induced expression of Bcl3, PD-L1 and IL-8/CXCL8, which have long been known to have critical cellular functions as a proto-oncogene, an immune checkpoint ligand and a chemoattractant, respectively. However, overwhelming evidence has demonstrated that these three genes have tumor-promoting roles far beyond their originally identified functions. These tumor-promoting mechanisms include increased cancer cell proliferation, invasion, angiogenesis, metastasis, resistance to chemotherapy and immune escape. Recent studies have shown that IFNγ-induced Bcl3, PD-L1 and IL-8 expression is regulated by the same JAK1/STAT1 signaling pathway: IFNγ induces the expression of Bcl3, which then promotes the expression of PD-L1 and IL-8 in OC cells, resulting in their increased proliferation and migration. In this review, we summarize the recent findings on how IFNγ affects the tumor microenvironment and promotes tumor progression, with a special focus on ovarian cancer and on Bcl3, PD-L1 and IL-8/CXCL8 signaling. We also discuss promising novel combinatorial strategies in clinical trials targeting Bcl3, PD-L1 and IL-8 to increase the effectiveness of cancer immunotherapies.

Suppression of Bcl3 Disrupts Viability of Breast Cancer Cells through Both p53-Dependent and p53-Independent Mechanisms via Loss of NF-κB Signalling

The NF-κB co-factor Bcl3 is a proto-oncogene that promotes breast cancer proliferation, metastasis and therapeutic resistance, yet its role in breast cancer cell survival is unclear. Here, we sought to determine the effect of Bcl3 suppression alone on breast cancer cell viability, with a view to informing future studies that aim to target Bcl3 therapeutically. Bcl3 was suppressed by siRNA in breast cancer cell lines before changes in viability, proliferation, apoptosis and senescence were examined. Bcl3 suppression significantly reduced viability and was shown to induce apoptosis in all cell lines tested, while an additional p53-dependent senescence and senescence-associated secretory phenotype was also observed in those cells with functional p53. The role of the Bcl3/NF-κB axis in this senescence response was confirmed via siRNA of the non-canonical NF-κB subunit NFKB2/p52, which resulted in increased cellular senescence and the canonical subunit NFKB1/p50, which induced the senescence-associated secretory phenotype. An analysis of clinical data showed a correlation between reduced relapse-free survival in patients that expressed high levels of Bcl3 and carried a p53 mutation. Together, these data demonstrate a dual role for Bcl3/NF-κB in the maintenance of breast cancer cell viability and suggests that targeting Bcl3 may be more beneficial to patients with tumours that lack functional p53.

Multifaceted roles for BCL3 in cancer: a proto-oncogene comes of age

In the early 1990's a group of unrelated genes were identified from the sites of recurring translocations in B-cell lymphomas. Despite sharing the nomenclature 'Bcl', and an association with blood-borne cancer, these genes have unrelated functions. Of these genes, BCL2 is best known as a key cancer target involved in the regulation of caspases and other cell viability mechanisms. BCL3 on the other hand was originally identified as a non-canonical regulator of NF-kB transcription factor pathways - a signaling mechanism associated with important cell outcomes including many of the hallmarks of cancer. Most of the early investigations into BCL3 function have since focused on its role in NF-kB mediated cell proliferation, inflammation/immunity and cancer. However, recent evidence is coming to light that this protein directly interacts with and modulates a number of other signaling pathways including DNA damage repair, WNT/β-catenin, AKT, TGFβ/SMAD3 and STAT3 - all of which have key roles in cancer development, metastatic progression and treatment of solid tumours. Here we review the direct evidence demonstrating BCL3's central role in a transcriptional network of signaling pathways that modulate cancer biology and treatment response in a range of solid tumour types and propose common mechanisms of action of BCL3 which may be exploited in the future to target its oncogenic effects for patient benefit.

Docking of T6361 Analogues as Potential Inhibitors of E.coli MurA Followed by ADME-Toxicity Study

BACKGROUND

Developing more potent antibacterial agents is one of the most important tasks of scientists in the health field due to the problem of antibiotic resistance. Among the antibiotic targets, we mention MurA (UDP-N-Acetylglucosamine Enolpyruvyl Transferase), which is a key enzyme of peptidoglycan biosynthesis of the bacterial cell wall.

OBJECTIVE

Our objective was to search for new inhibitors of the bacterial enzyme MurA by docking the analogues of its inhibitor T6361, a derivative of 5-sulfonoxy-anthranilic acid.

METHODS

990 analogues of T6361 were docked in the first binding site of E.coli MurA (open form) using the FlexX program, and the ADME-Toxicity profile of the best ones was evaluated by SwissADME and PreADMET web servers. .

RESULTS

Docking results revealed two T6361 analogues to provide better energy scores than T6361, and have similar interactions with the binding site of E.coli MurA namely,3-{[2-(piperidine-1-carbonyl) phenyl]sulfamoyl}benzoic acid and 3-{[2-(pyrrolidine-1 carbonyl)phenyl]sulfamoyl}benzoic acid. Moreover, the two molecules were found to possess good pharmacokinetics and low toxicity.

CONCLUSION

We propose two analogues of T6361 as new potential inhibitors of MurA enzyme. Their good ADME-Toxicity profile qualifies them to reach in vitro and in vivo assays as future lead molecules.

BCL-3 loss sensitises colorectal cancer cells to DNA damage by targeting homologous recombination

The proto-oncogene BCL-3 is upregulated in a subset of colorectal cancers (CRC), where it has been shown to enhance tumour cell survival. However, although increased expression correlates with poor patient prognosis, the role of BCL-3 in determining therapeutic response remains largely unknown. In this study, we use combined approaches in multiple cell lines and pre-clinical mouse models to investigate the function of BCL-3 in the DNA damage response. We show that suppression of BCL-3 increases γH2AX foci formation and decreases homologous recombination in CRC cells, resulting in reduced RAD51 foci number and increased sensitivity to PARP inhibition. Importantly, a similar phenotype is seen in Bcl3-/- mice, where Bcl3-/- mouse crypts also exhibit sensitivity to DNA damage with increased γH2AX foci compared to wild type mice. Additionally, Apc.Kras-mutant x Bcl3-/- mice are more sensitive to cisplatin chemotherapy compared to wild type mice. Taken together, our results identify BCL-3 as a regulator of the cellular response to DNA damage and suggests that elevated BCL-3 expression, as observed in CRC, could increase resistance of tumour cells to DNA damaging agents including radiotherapy. These findings offer a rationale for targeting BCL-3 in CRC as an adjunct to conventional therapies and suggest that BCL-3 expression in tumours could be a useful biomarker in stratification of rectal cancer patients for neo-adjuvant chemoradiotherapy.

Nasopharyngeal Carcinoma and Its Microenvironment: Past, Current, and Future Perspectives

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy that raises public health concerns in endemic countries. Despite breakthroughs in therapeutic strategies, late diagnosis and drug resistance often lead to unsatisfactory clinical outcomes in NPC patients. The tumor microenvironment (TME) is a complex niche consisting of tumor-associated cells, such as fibroblasts, endothelial cells, leukocytes, that influences tumor initiation, progression, invasion, and metastasis. Cells in the TME communicate through various mechanisms, of note, exosomes, ligand-receptor interactions, cytokines and chemokines are active players in the construction of TME, characterized by an abundance of immune infiltrates with suppressed immune activities. The NPC microenvironment serves as a target-rich niche for the discovery of potential promising predictive or diagnostic biomarkers and the development of therapeutic strategies. Thus, huge efforts have been made to exploit the role of the NPC microenvironment. The whole picture of the NPC microenvironment remains to be portrayed to understand the mechanisms underlying tumor biology and implement research into clinical practice. The current review discusses the recent insights into the role of TME in the development and progression of NPC which results in different clinical outcomes of patients. Clinical interventions with the use of TME components as potential biomarkers or therapeutic targets, their challenges, and future perspectives will be introduced. This review anticipates to provide insights to the researchers for future preclinical, translational and clinical research on the NPC microenvironment.