The possible role of Cytochrome c and programmed cell death protein 4 (PDCD4) on pathogenesis of hepatocellular carcinoma

Mitochondrial metabolism as a dynamic regulatory hub to malignant transformation and anti-cancer drug resistance

Glycolysis is the fundamental cellular process that permits cancer cells to convert energy and grow anaerobically. Recent developments in molecular biology have made it evident that mitochondrial respiration is critical to tumor growth and treatment response. As the principal organelle of cellular energy conversion, mitochondria can rapidly alter cellular metabolic processes, thereby fueling malignancies and contributing to treatment resistance. This review emphasizes the significance of mitochondrial biogenesis, turnover, DNA copy number, and mutations in bioenergetic system regulation. Tumorigenesis requires an intricate cascade of metabolic pathways that includes rewiring of the tricarboxylic acid (TCA) cycle, electron transport chain and oxidative phosphorylation, supply of intermediate metabolites of the TCA cycle through amino acids, and the interaction between mitochondria and lipid metabolism. Cancer recurrence or resistance to therapy often results from the cooperation of several cellular defense mechanisms, most of which are connected to mitochondria. Many clinical trials are underway to assess the effectiveness of inhibiting mitochondrial respiration as a potential cancer therapeutic. We aim to summarize innovative strategies and therapeutic targets by conducting a comprehensive review of recent studies on the relationship between mitochondrial metabolism, tumor development and therapeutic resistance.

Apoptotic proteins with non-apoptotic activity: expression and function in cancer

Apoptosis is a process of programmed cell death in which a cell commits suicide while maintaining the integrity and architecture of the tissue as a whole. Apoptosis involves activation of one of two major pathways: the extrinsic pathway, where extracellular pro-apoptotic signals, transduced through plasma membrane death receptors, activate a caspase cascade leading to apoptosis. The second, the intrinsic apoptotic pathway, where damaged DNA, oxidative stress, or chemicals, induce the release of pro-apoptotic proteins from the mitochondria, leading to the activation of caspase-dependent and independent apoptosis. However, it has recently become apparent that proteins involved in apoptosis also exhibit non-cell death-related physiological functions that are related to the cell cycle, differentiation, metabolism, inflammation or immunity. Such non-conventional activities were predominantly reported in non-cancer cells although, recently, such a dual function for pro-apoptotic proteins has also been reported in cancers where they are overexpressed. Interestingly, some apoptotic proteins translocate to the nucleus in order to perform a non-apoptotic function. In this review, we summarize the unconventional roles of the apoptotic proteins from a functional perspective, while focusing on two mitochondrial proteins: VDAC1 and SMAC/Diablo. Despite having pro-apoptotic functions, these proteins are overexpressed in cancers and this apparent paradox and the associated pathophysiological implications will be discussed. We will also present possible mechanisms underlying the switch from apoptotic to non-apoptotic activities although a deeper investigation into the process awaits further study.

Cytochrome c: Using Biological Insight toward Engineering an Optimized Anticancer Biodrug

The heme protein cytochrome c (Cyt c) plays pivotal roles in cellular life and death processes. In the respiratory chain of mitochondria, it serves as an electron transfer protein, contributing to the proliferation of healthy cells. In the cell cytoplasm, it activates intrinsic apoptosis to terminate damaged cells. Insight into these mechanisms and the associated physicochemical properties and biomolecular interactions of Cyt c informs on the anticancer therapeutic potential of the protein, especially in its ability to subvert the current limitations of small molecule-based chemotherapy. In this review, we explore the development of Cyt c as an anticancer drug by identifying cancer types that would be receptive to the cytotoxicity of the protein and factors that can be finetuned to enhance its apoptotic potency. To this end, some information is obtained by characterizing known drugs that operate, in part, by triggering Cyt c induced apoptosis. The application of different smart drug delivery systems is surveyed to highlight important features for maintaining Cyt c stability and activity and improving its specificity for cancer cells and high drug payload release while recognizing the continuing limitations. This work serves to elucidate on the optimization of the strategies to translate Cyt c to the clinical market.

Concerted hepatoprotective effect of bradykinin potentiating factor and low dose of γ- radiation on Naja haje envenomed rats via Bax/Bcl2 pathway

This study investigates the concerted hepatoprotective effects for three doses of bradykinin potentiating factor (BPF) and/or followed by exposure to a low dose of γ-radiation (LDR) against Naja haje envenoming in rats. Male rats were injected with three consecutive doses of BPF (1 μg/g i.p. for 3 days), followed by exposure to a low dose of gamma radiation (0.5 Gy), and then rats were injected with a dose of Naja haje venom (250 μg/kg i.p.). Results showed that Naja haje causes liver damage, significant elevation of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), cytochrome c, Nitric oxide (NO), malondialdehyde (MDA) and significant depletion in glutathione peroxidase (GPx) contents. In addition, significant depletion in B-cell lymphoma 2 (Bcl-2) and significant elevation in BcL-2 associated X (Bax protein), nuclear factor kappa B (NF-κB), interleukin-1β (IL-1β) in hepatocytes. Bradykinin potentiating factor and/or low dose of γ-radiation caused improvement in liver damage caused by Naja haje venom by a significant decrease in ALT, AST, ALP levels, Bax, cytochrome c, NF-κB, IL-1β, NO and MDA contents, BPF alone or combined with low dose radiation caused a significant increase in Bcl2 and GPx contents. In conclusion, the concerted impact of BPF and LDR may provide an effective venom detoxification tool that helps to reduce hepatic toxicity and extends the lifespan.

Herbicide Widespread: The Effects of Pethoxamid on Nonalcoholic Fatty Liver Steatosis In Vitro

Pethoxamid is a widespread herbicidal product, presenting itself as an extremely flexible active substance and with a high potential for use as an herbicide for preemergence. The emergence of multiple resistance in crops has been addressed using combinations of preemergence and postemergence herbicides in the same seeding-harvest cycle. A winning combination of pethoxamid and glyphosate mainly affected the acidobacteria population. Glyphosate scientific literature has demonstrated an observational link between herbicide exposure and liver disease in human subjects. Identifying and ranking the risk to the public that pethoxamid could exert on target organs has not been evaluated so far. Due to similarities to glyphosate, we did look at the effect of pethoxamid on impaired liver cells HepG2, using a nonalcoholic fatty liver disease (NAFLD) cell model in vitro. Pethoxamid was cytotoxic starting at 1 ppm. Fatty acid accumulation (FA) was enhanced while low doses of pethoxamid slightly decreased LDH protein expression compared to FA-treated HepG2. The same trend was observed for cytochrome c. Based on our data, we can argue that NAFLD hepatic cells react to pethoxamid trying detoxifying strategies, ready to undergo cell death to avoid further degeneration. Downregulation of cytochrome can lead to the hypothesis that pethoxamid should not induce herbicide resistance.

MicroRNA-182 Promotes Cell Migration by Targeting Programmed Cell Death 4 in Hepatocellular Carcinoma Cells

Purpose

Hepatocellular carcinoma (HCC) is the most common primary liver tumor and the third greatest cause of cancer-related death worldwide. Programmed cell death 4 (PDCD4) was reported as a potential tumor-suppressor in hepatocarcinogenesis. However, relatively little is known about mechanisms that regulate PDCD4 expression in HCC. The aim of the present study is to investigate the expression of PDCD4 and miR-182 in human HCC cell lines and clinical HCC specimens and determine whether PDCD4 is a direct target of miR-182 in HCC cell lines.

Materials

The expression of miR-182 and PDCD4 in human HCC cell lines and HCC tissues were examined using qRT-PCR and Western blot method. Transwell and wound healing assays were carried out to explore the influence of miR-182 on hepatoma cells migration. A luciferase reporter assay was conducted to confirm target association.

Results

In our research, we found that PDCD4 was downregulated, whereas miR-182 was upregulated in liver cancer cell lines and HCC tissues. Transwell and wound healing assays illustrated that miR-182 contributed to migration activities of liver cancer cell lines. Loss or increase of miR-182 can lead to a negative expression of PDCD4 protein level. The luciferase reporter assay showed that PDCD4 is a direct target of miR-182.

Conclusion

All these findings suggest that miR-182 may act as an oncogenic role in liver cancer cells by directly and negatively regulating expression of PDCD4.

Calcitonin receptor is required for T-antigen-induced prostate carcinogenesis

Expression of calcitonin (CT) and its receptor (CTR) is frequently elevated in prostate cancer (PC) and activation of CT–CTR axis in non- invasive PC cells induces an invasive phenotype. However, the role of CT-CTR axis in prostate carcinogenesis has not been investigated. We employed a transgenic mouse prostate cancer model that uses long probasin promoter to target the expression of T-antigen in the prostate gland (LPB-Tag) along with CTR knock-out mice (CTRKO) to address this question. We cross-bred LPB-Tag mice with CTRKO to obtain four groups of mice. Prostates of these mice were obtained at the age of 90 days, fixed, paraffin-embedded, and used either for the extraction of RNA or for immunofluorescence. Prostate RNAs from different groups were reverse transcribed and used either for transcription profiling or for qRT-PCR. As expected, prostates of mice with LPB-Tag genotype displayed well-grown tumors with histologic features such as loss of normal morphology and nuclear atypia. WT as well as CTRKO mice displayed normal prostate morphology. Interestingly, LPB-Tag-CTRKO prostates also displayed relatively normal morphology which was indistinguishable from the WT. Microarray analysis as well as qRT-PCR suggested that CTRKO genotype reversed T-antigen-induced silencing of RB and PTEN gene expression as well as T-antigen-induced expression of several enzymes associated with lipid metabolism/ cholesterol biosynthesis, several cancer-related and androgen-regulated genes. The results for the first time identify mechanisms associated CTR-induced prostate carcinogenesis, and raise an exciting possibility of using a potent CT antagonist to attenuate progression of prostate cancer.