Apoptotic and Non-Apoptotic Modalities of Thymoquinone-Induced Lymphoma Cell Death: Highlight of the Role of Cytosolic Calcium and Necroptosis

Single and Combinatorial Effects of Metformin and Thymoquinone in Diffuse Large B Cell Lymphoma Cells

Diffuse large B cell lymphoma (DLBCL) is classified into Germinal Center B-cell (GCB) and activated B-cell (ABC) subgroups originating from different stages of lymphoid differentiation. Cell of origin dictates the behavior and therapeutic response of DLBCL. This study aimed to evaluate single and combinatorial effects of metformin and thymoquinone (TQ) in two DLBCL cell lines belonging to GCB and ABC subtypes. Metformin and TQ caused dose-dependent responses in both ABC and GCB DLBCL subtypes. Metformin had a greater impact on the ABC subtype while TQ demonstrated more pronounced effects on the GCB subtype. Synergistic effects were observed in the DHL4 (GCB subtype) but not in the HBL1 (ABC subtype) cell line. This is the first study to compare the effects of metformin and TQ in ABC versus GCB subtype of DLBCL. It brings valuable results that could be utilized in further research aimed at reshaping treatments for subtype-specific lymphomas.

Application of urine proteomics in the diagnosis and treatment effectiveness monitoring of early-stage Mycosis Fungoides

BACKGROUND

Mycosis fungoides (MF) is the most common type of cutaneous T cell lymphoma. As the early clinical manifestations of MF are non-specific (e.g., erythema or plaques), it is often misdiagnosed as inflammatory skin conditions (e.g., atopic dermatitis, psoriasis, and pityriasis rosea), resulting in delayed treatment. As there are no effective biological markers for the early detection and management of MF, the aim of the present study was to perform a proteomic analysis of urine samples (as a non-invasive protein source) to identify reliable MF biomarkers.

METHODS

Thirteen patients with early-stage MF were administered a subcutaneous injection of interferon α-2a in combination with phototherapy for 6 months. The urine proteome of patients with early-stage MF before and after treatment was compared against that of healthy controls by liquid chromatography-tandem mass spectrometry. The differentially expressed proteins were subjected to Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Clusters of Orthologous Groups analyses. For validation, the levels of the selected proteins were evaluated by enzyme-linked immunosorbent assay (ELISA).

RESULTS

We identified 41 differentially expressed proteins (11 overexpressed and 30 underexpressed) between untreated MF patients and healthy control subjects. The proteins were mainly enriched in focal adhesion, endocytosis, and the PI3K-Akt, phospholipase D, MAPK, and calcium signaling pathways. The ELISA results confirmed that the urine levels of Serpin B5, epidermal growth factor (EGF), and Ras homologous gene family member A (RhoA) of untreated MF patients were significantly lower than those of healthy controls. After 6 months of treatment, however, there was no significant difference in the urine levels of Serpin B5, EGF, and RhoA between MF patients and healthy control subjects. The area under the receiver operating characteristic curve values for Serpin B5, EGF, and RhoA were 0.817, 0.900, and 0.933, respectively.

CONCLUSIONS

This study showed that urine proteomics represents a valuable tool for the study of MF, as well as identified potential new biomarkers (Serpin B5, EGF, and RhoA), which could be used in its diagnosis and management.

Targeting regulated cell death (RCD) in hematological malignancies: Recent advances and therapeutic potential

Regulated cell death (RCD) is a form of cell death that can be regulated by numerous biomacromolecules. Accumulating evidence suggests that dysregulated expression and altered localization of related proteins in RCD promote the development of cancer. Targeting subroutines of RCD with pharmacological small-molecule compounds is becoming a promising therapeutic avenue for anti-tumor treatment, especially in hematological malignancies. Herein, we summarize the aberrant mechanisms of apoptosis, necroptosis, pyroptosis, PANoptosis, and ferroptosis in hematological malignancies. In particular, we focus on the relationship between cell death and tumorigenesis, anti-tumor immunotherapy, and drug resistance in hematological malignancies. Furthermore, we discuss the emerging therapeutic strategies targeting different RCD subroutines. This review aims to summarize the significance and potential mechanisms of RCD in hematological malignancies, along with the development and utilization of pertinent therapeutic strategies.

Connexin 43 regulates pyroptosis by influencing intracellular calcium levels in X-ray induced vascular endothelial cell damage

OBJECTIVE

Our prior research has established that X-ray exposure induces pyroptosis in human umbilical vein endothelial cells (HUVECs), with Cx43 playing a regulatory role in this process. However, the precise mechanism by which Cx43 regulates pyroptosis remains unclear. The objective of this study is to assess the involvement of the calcium signaling pathway in Cx43-mediated regulation of X-ray-induced pyroptosis in HUVECs.

METHODS

HUVECs were exposed to 10 Gy X-ray radiation either alone or combined with Cx43 overexpression or knockdown. Calcium ions (Ca2+) were stained using Fluo-4/AM and analyzed via flow cytometry and confocal microscopy. Pyroptosis was assessed through flow cytometry by staining with FLICA (fluorescent-labeled inhibitor of caspase) and propidium iodide (PI). Calcium signaling was inhibited using BAPTA/AM, 2-APB, or nifedipine. Protein expression levels were assessed by western blotting.

RESULTS

X-ray irradiation induced an increase in intracellular calcium levels in HUVECs in a dose- and time-dependent manner. The results demonstrated that regulating calcium release with BAPTA/AM, 2-APB, or nifedipine significantly reduced pyroptosis. Also, the overexpression of Cx43 significantly attenuated the increase in intracellular calcium. Conversely, Cx43 knockdown via siRNA significantly increased the intracellular calcium levels. Also, interfering with calcium signaling using BAPTA/AM, 2-APB, or nifedipine reduced the raised pyroptosis levels induced by Cx43 knockdown.

CONCLUSION

Individual HUVECs exposed to high-dose X-ray irradiation exhibited an increase in intracellular calcium, leading to pyroptosis. Also, upregulating Cx43 expression reduced the pyroptosis levels by inhibiting intracellular calcium concentration. This study introduces new concepts for identifying targets for the prophylaxis and therapy of radiation-induced damage.

Potential anticancer properties and mechanisms of thymoquinone in colorectal cancer

Colorectal neoplasms are one of the deadliest diseases among all cancers worldwide. Thymoquinone (TQ) is a natural compound of Nigella sativa that has been used in traditional medicine against a variety of acute/chronic diseases such as asthma, bronchitis, rheumatism, headache, back pain, anorexia, amenorrhea, paralysis, inflammation, mental disability, eczema, obesity, infections, depression, dysentery, hypertension, gastrointestinal, cardiovascular, hepatic, and renal disorders. This review aims to present a detailed report on the studies conducted on the anti-cancer properties of TQ against colorectal cancer, both in vitro and in vivo. TQ stands as a promising natural therapeutic agent that can enhance the efficacy of existing cancer treatments while minimizing the associated adverse effects. The combination of TQ with other anti-neoplastic agents promoted the efficacy of existing cancer treatments. Further research is needed to acquire a more comprehensive understanding of its exact molecular targets and pathways and maximize its clinical usefulness. These investigations may potentially aid in the development of novel techniques to combat drug resistance and surmount the obstacles presented by chemotherapy and radiotherapy.

Telomerase inhibitors TMPyP4 and thymoquinone decreased cell proliferation and induced cell death in the non-small cell lung cancer cell line LC-HK2, modifying the pattern of focal adhesion

G-quadruplexes (G4) are structures formed at the ends of telomeres rich in guanines and stabilized by molecules that bind to specific sites. TMPyP4 and thymoquinone (TQ) are small molecules that bind to G4 and have drawn attention because of their role as telomerase inhibitors. The aim of this study was to evaluate the effects of telomerase inhibitors on cellular proliferation, senescence, and death. Two cell lines, LC-HK2 (non-small cell lung cancer - NSCLC) and RPE-1 (hTERT-immortalized), were treated with TMPyP4 (5 μM) and TQ (10 μM). Both inhibitors decreased telomerase activity. TMPyP4 increased the percentage of cells with membrane damage associated with cell death and decreased the frequency of cells in the S-phase. TMPyP4 reduced cell adhesion ability and modified the pattern of focal adhesion. TQ acted in a concentration-dependent manner, increasing the frequency of senescent cells and inducing cell cycle arrest in G1 phase. Thus, the present results showed that TMPyP4 and TQ, although acting as telomerase inhibitors, had a broader effect on other signaling pathways and processes in cells, differing from each other. However, they act both on malignant and immortalized cells, and further studies are needed before their anti-cancer potential can be considered.

Thymoquinone induces apoptosis in temozolomide-resistant glioblastoma cells via the p38 mitogen-activated protein kinase signaling pathway

Temozolomide (TMZ) can cross the blood-brain barrier (BBB) and deliver methyl groups to the purine (guanine) bases of DNA, leading to mispairing during DNA replication and subsequent cell death. However, increased expression of the repair enzyme methyl guanine methyltransferase (MGMT), which removes methyl groups from purine bases, counteracts methylation by TMZ. We evaluated the anticancer potential of thymoquinone (TQ), a hydrophobic flavonoid that inhibits resistance and induces apoptosis in various cancer cells, both in vitro and in vivo. In vitro experiments showed that compared with the Hs683 and M059J cell lines, U251 cells were more sensitive to TMZ. Compared to U251 cells, U251R cells, a TMZ drug-resistant strain established in this study, are characterized by increased expression of phosphorylated extracellular signal-regulated kinase (p-ERK) and MGMT. TQ treatments induced apoptosis in all cell lines. The p38 mitogen-activated protein kinase signal pathway was mainly activated in U251 and U251R cells; however, p-ERK and MGMT upregulation could not suppress TQ effects. Furthermore, si-p38 pretreatment of U251R cells in TQ treatments inhibited cell apoptosis. We speculate that TQ contributed to the phosphorylation and activation of p38, but not of ERK-induced apoptosis (irrespective of TMZ resistance). In vivo, U251R-derived tumors subcutaneously inoculated in nude mice exhibited significant tumor volume reduction after TQ or TQ + TMZ cotreatments. High-performance liquid chromatography assay confirmed the presence of TQ in murine brain tissues. Our findings demonstrate that TQ can effectively cross the BBB and function alone or in combination with TMZ to treat glioblastoma.

Identification and Assessment of Necroptosis-Related Genes in Clinical Prognosis and Immune Cells in Diffuse Large B-Cell Lymphoma

Background

With the unveiling of new mechanisms and the advent of new drugs, the prognosis of diffuse large B-cell lymphoma (DLBCL) becomes promising, but some patients still progress to the relapse or refractory stage. Necroptosis, as a relatively novel programmed cell death, is involved in the development of multiple tumors. There are no relevant studies on the prognostic significance of necroptosis in DLBCL to date.

Methods

We identified the differential necroptosis-related genes (NRGs) by comparing the DLBCL and normal control in GSE12195 and GSE56315 datasets. TCGA DLBC and GSE10846 containing clinical information and microarray expression profiling were merged as the entire cohort. We performed consensus clusters based on NRGs and two clusters were obtained. Kaplan–Meier (K-M) survival analysis, GSVA, GO, KEGG, and ssGSEA were used to analyze the survival, function, and immune microenvironment between two clusters. With LASSO and proportional hazard model construction, we identified differentially expressed genes (DEGs) between NRG clusters, calculated the risk score, established a prognostic model, and validated its value by calibration and ROC curves. The entire cohort was divided into the training and test cohort, and GSE87371 was included as an external validation cohort. K-M, copy number variation, tumor mutation burden, and drug sensitivity were also analyzed.

Results

We found significant differences in prognosis between the two NRG clusters. Cluster A with a poor prognosis had a decreased expression of NRGs and a relatively suppressed immune microenvironment. GSVA analysis indicated that cluster A was related to the downregulation of the TGF-β signaling pathway and the activation of the Notch signaling pathway. The risk score had an accurate predictive ability. The nomogram could help predict the survival probability of DLBCL patients in the entire cohort and the external validation cohort. The area under the curve (AUC) of the nomogram, risk score, and International Prognostic Index was 0.723, 0.712, and 0.537, respectively. γ/δ T cells and Macrophage 1 cells decreased while Macrophage 2 cells and Natural Killer resting cells increased in the high-risk group. In addition, the high-risk group was more sensitive to the PI3K inhibitor and the PDK inhibitor.

Conclusion

We explored the potential role of necroptosis in DLBCL from multiple perspectives and provided a prognostic nomogram for the survival prediction of DLBCL. Necroptosis was downregulated and was correlated with an immunosuppressed tumor microenvironment and poor prognosis in DLBCL. Our study may deepen the understanding and facilitate the development of new therapy targets for DLBCL.