Pharmacological Targeting of Bcl-2 Induces Caspase 3-Mediated Cleavage of HDAC6 and Regulates the Autophagy Process in Colorectal Cancer

The role of Bcl‑2 in controlling the transition between autophagy and apoptosis (Review)

The Bcl‑2 protein family serves a key role in maintaining cellular homeostasis by regulating the balance between autophagy and apoptosis. The present review aimed to summarize interactions of Bcl‑2 with key proteins, including Beclin 1, Bax and Bcl‑2 homologous antagonist/killer, as well as its influence on cellular processes such as mitophagy, nutrient sensing and endoplasmic reticulum stress response. The impact of post‑translational modifications of Bcl‑2, including phosphorylation, ubiquitination and sumoylation, is discussed with respect to their regulatory roles under stress. In pathological states, Bcl‑2 upregulation in cancer suppresses apoptosis and autophagy, thereby facilitating tumor survival and resistance to chemotherapy. Conversely, in neurodegenerative diseases, impaired autophagy and increased apoptosis contribute to neuronal loss. Therapeutic strategies targeting Bcl‑2 (for example inhibitors such as venetoclax, navitoclax, obatoclax and combination therapies involving autophagy modulators) were evaluated for their potential efficacy. There is lack of understanding of tissue‑specific functions of Bcl‑2 and its interactions with non‑coding RNAs. Future research should prioritize these areas and leverage advanced single‑cell technologies to elucidate the real‑time dynamics of Bcl‑2 in cell processes. The present review highlights the key role of Bcl‑2 in cell fate determination and highlights its potential as a therapeutic target, offering insight for the development of innovative treatments for cancer, neurodegenerative disorder and age‑related diseases.

0.5 Gy confers resistance to a subsequent high dose of γ-rays by modulating HO-1/Nrf2 and apoptosis pathways

Ionizing radiation, from the DNA centric view, elicits biological effects and health consequences solely through energy deposition events in the cell nucleus. At higher radiation doses, this is likely true; however, at low doses, non-targeted effects, a subcategory of which is the adaptive response, tend to dominate. Controversies exist over the definition of low dose. From a radiation therapy view, it is defined as 0.5-0.7 Gy. Therefore, we investigated the effects of exposure to ionizing radiation with or without a 0.5 Gy priming dose. Techniques including comet assay, flow cytometry, fluorescence microscopy, and real-time quantitative PCR were employed. In normal lung fibroblasts (WI-38), there was a statistically significant difference in mean normalized tail moments when comparing treatment with the challenge dose alone to treatment with a 0.5 Gy priming dose prior to the challenge dose (P < 0.05). Moreover, pretreatment with a 0.5 Gy priming dose reduced G1 phase cell cycle arrest and cell death-either through apoptosis or mitotic catastrophe-induced by the subsequent 2 Gy exposure. Similarly, A549 Cells pre-exposed to a 0.5 Gy priming dose before a 2 Gy exposure showed a lower percentage of apoptosis than those exposed to the 2 Gy alone. Mechanistically, cells responded to a priming 0.5 Gy by increasing the expression of HMOX1, SOD, and Bcl2 while decreasing of IL-1β and TNF-α. In conclusion, 0.5 Gy induces an adaptive response in lung normal and cancer cell against subsequent high doses of γ-rays. Modulation of the HO-1/Nrf2 and apoptosis pathways underlie the resistance observed in primed cells.

In Vitro and In Vivo Anticancer Activities of Water-Soluble Ru(II)(η6-p-cymene) Complexes via Activating Apoptosis Central Regulators and Possibilities of New Antitumor Strategies in Triple Negative Breast Cancers

In this study, we synthesized 12 monofunctional tridentate ONS-donor salicylaldimine ligand (L)-based Ru(II) complexes with general formula [(Ru(L)(p-cymene)]+·Cl- (C1-C12), characterized by 1H NMR, 13C NMR, UV, FT-IR spectroscopy, HR-ESI mass spectrometry, and single-crystal X-ray analysis showing ligand's orientation around the Ru(II) center. All 12 of these 12 complexes were tested for their anticancer activities in multiple cancer cells. The superior antitumor efficacy of C2, C8, and C11 was demonstrated by reduced mitochondrial membrane potential, impaired proliferative capacity, and disrupted redox homeostasis, along with enhanced apoptosis through caspase-3 activation and downregulation of Bcl-2 expression. In the 4T1 breast cancer orthotopic mouse model, assessment of bioluminescence for metastatic spread, tumor burden, histopathological evaluation, immunohistochemistry (IHC), and hematological profiling and tissue Protein expression of caspase-3, cleaved caspase-3, TNF-α, and bcl-2 demonstrated that C8 treatment led to prolonged survival and suppressed tumor progression in triple negative breast cancer.

The pathological and immunohistochemical profile of tumor angiogenesis in perforated sigmoid carcinoma–Case report and short literature review

<b>Background:</b> Little is known about the physiopathological factors or mechanisms that underlie tumor invasion of the serosa and lead to perforation in the peritoneal cavity. The aim of the work was to analyze the pathological and immunohistochemical factors of tumor neoangiogenesis which could influence tumor perforation in colorectal cancer.<br /> <b>Results and discussions:</b> 451 cases of complicated colorectal carcinomas were statistically analyzed, of which 19 cases were perforated sigmoid tumors. The immunohistochemical detection of mutant p53 proteins was the first molecular parameter examined in the context of the search for markers predicting the natural evolution mode in colorectal carcinomas.<br /> <b>Conclusions</b>: Both loss of p53 and overexpression of bcl-2 proteins confer immortalization on cancer cells by inhibiting the processes leading to apoptosis. The paper proposes a review of the specialized literature, but also the presentation of a clinical case.

[Solasonine promotes apoptosis of non-small cell lung cancer cells by regulating the Bcl-2/Bax/caspase-3 pathway]

OBJECTIVE

To investigate the effect of solasonine, an active component of Solanum nigrum, on proliferation and apoptosis of non-small cell lung cancer PC9 cells.

METHODS

PC9 cells were treated with 2, 5, 10, 15, 20, or 25 μmol/L solasonine, and the changes in cell proliferation were examined using CCK-8 assay. Tetramethyl rhodamine ethyl ester (TMRE) was used to detect the changes in mitochondrial membrane potential, and caspase-3/7 detection kit and GreenNucTM caspase-3/Annexin V-mCherry kit for live cell were used to analyze the changes in caspase-3 of the cells. Annexin V-FITC/PI double staining was employed to analyze the apoptosis rate of the cells. The effect of PTEN inhibitors on solasonine-induced cell apoptosis was examined by detecting apoptosis-related protein expressions using Western blotting.

RESULTS

Solasonine treatment for 24, 48, and 72 h significantly lowered the viability of PC9 cells. The cells treated with solasonine for 24 h showed significantly decreased mitochondrial membrane potential and increased cell apoptosis with enhanced caspase-3/7 and caspase-3 activities and expression of cleaved caspase-3. Solasonine treatment significantly decreased phosphorylation levels of PI3K and Akt, increased the protein expressions of PTEN and Bax, and lowered the expression of Bcl-2 protein in the cells.

CONCLUSION

Solasonine inhibits proliferation and induces apoptosis of PC9 cells by regulating the Bcl-2/Bax/caspase-3 pathway and its upstream proteins.

A novel HDAC6 inhibitor interferes microtubule dynamics and spindle assembly checkpoint and sensitizes cisplatin-induced apoptosis in castration-resistant prostate cancer

BACKGROUND

Metastatic castration-resistant prostate cancer (CRPC), the most refractory prostate cancer, inevitably progresses and becomes unresponsive to hormone therapy, revealing a pressing unmet need for this disease. Novel agents targeting HDAC6 and microtubule dynamics can be a potential anti-CRPC strategy.

METHODS

Cell proliferation was examined in CRPC PC-3 and DU-145 cells using sulforhodamine B assay and anchorage-dependent colony formation assay. Flow cytometric analysis of propidium iodide staining was used to determine cell-cycle progression. Cell-based tubulin polymerization assay and confocal immunofluorescence microscopic examination determine microtubule assembly/disassembly status. Protein expressions were determined using Western blot analysis.

RESULTS

A total of 82 novel derivatives targeting HDAC6 were designed and synthesized, and Compound 25202 stood out, showing the highest efficacy in blocking HDAC6 (IC50, 3.5 nM in enzyme assay; IC50, 1.0 μM in antiproliferative assay in CRPC cells), superior to tubastatin A (IC50, 5.4 μM in antiproliferative assay). The selectivity and superiority of 25202 were validated by examining the acetylation of both α-tubulin and histone H3, detecting cell apoptosis and HDACs enzyme activity assessment. Notably, 25202 but not tubastatin A significantly decreased HDAC6 protein expression. 25202 prolonged mitotic arrest through the detection of cyclin B1 upregulation, Cdk1 activation, mitotic phosphoprotein levels, and Bcl-2 phosphorylation. Compound 25202 did not mimic docetaxel in inducing tubulin polymerization but disrupted microtubule organization. Compound 25202 also increased the phosphorylation of CDC20, BUB1, and BUBR1, indicating the activation of the spindle assembly checkpoint (SAC). Moreover, 25202 profoundly sensitized cisplatin-induced cell death through impairment of cisplatin-evoked DNA damage response and DNA repair in both ATR-Chk1 and ATM-Chk2 pathways.

CONCLUSION

The data suggest that 25202 is a novel selective and potent HDAC6 inhibitor. Compound 25202 blocks HDAC6 activity and interferes microtubule dynamics, leading to SAC activation and mitotic arrest prolongation that eventually cause apoptosis of CRPC cells. Furthermore, 25202 sensitizes cisplatin-induced cell apoptosis through impeding DNA damage repair pathways.

IGF‑1 inhibits palmitic acid‑induced mitochondrial apoptosis in macrophages

Insulin growth factor‑1 (IGF‑1) is an endocrine regulator that plays an important role in normal growth and development. IGF‑1 mediated effects may result in protecting macrophages from immunometabolic response. However, it is unclear whether IGF‑1 has a protective effect on fatty acid‑induced macrophages damage. In the present study, THP‑1 cells were differentiated into macrophages and stimulated with palmitic acid (PA) in the absence or presence of IGF‑1. Macrophages apoptosis was measured by Cell Counting Kit‑8 assay, flow cytometry, Hoechst 33342 staining and western blotting. The mitochondrial damage was evaluated using JC‑1 staining and mitochondrial reactive oxygen species detection. The activation of mitophagy was assessed using immunofluorescence and western blotting. As a result, IGF‑1 significantly restored the survival rate in macrophages, while the apoptosis was inhibited through mitochondrial pathway. In addition, IGF‑1 protected the mitochondrial damage induced by PA. Furthermore, PA induced mitophagy via phosphatase and tensin homolog‑induced putative kinase protein 1/Parkin, which was reversed by IGF‑1. Taken together, the present study demonstrated the protective effect of IGF‑1 on PA‑induced mitochondrial apoptosis in macrophages, which might provide a potential therapeutic strategy for treatment of lipotoxicity.