Characterisation of methylglyoxal stress in human colorectal cancer and liver metastases using immunohistochemistry.

Background: Glycolysis is the principal source of energy for cancerous cells. One inevitable consequence of the elevated glycolytic rate is the production of highly reactive molecules such as methylglyoxal (MG). MG induces the glycation of proteins on lysine and arginine residues and generates protein adducts called MG-derived hydroimidazolones (MGHs). Glyoxalase 1 (GLO1) is the main detoxifying enzyme of MG. It is expressed in most eukaryotes and prokaryotes and is localized in the cytoplasmic compartment. An increase of GLO1 expression and activity is a cell defence mechanism against glycation damage induced under MG stress. Our previous studies reported the presence of MG protein adducts in CRC tumours and have linked MG stress with the resistance to targeted therapy in KRAS-mutated CRCs. Aims: In this pilot project, we undertook the detection of MG stress in human CRC primary tumours and liver metastases lesions. Methods: We have used immunohistochemistry and antibodies directed against MGHs protein adducts and GLO1 enzyme in CRC samples. Specific Ki67 antibodies were used for the evaluation of tumour proliferation rate. Results: By comparison of the same histological sample for GLO1 and Ki67 immunostainings, we observed that GLO1 enzyme was strongly detectable in the nucleus of undifferentiated and highly proliferative human CRC lesions. While most of the well-differentiated CRC tumours demonstrated undetectable to low nuclear GLO1 levels in the nucleus. Cytoplasmic GLO1 was similarly distributed among differentiated and non-differentiated tumours. Conclusion: It might be therefore interesting to explore further this peculiar GLO1 sub-localisation that could potentially indicate for the first time the presence of MG stress in the nucleus and the necessity for the nuclear translocation of GLO1 detoxifying enzyme in aggressive CRC lesions. Whether nuclear GLO1 detection could be a valuable marker in terms of unfavourable prognosis in CRC patients will be analysed on a large collection of CRC patients with documented clinical data and follow-up

Le ciblage de la myoferline induit la mitophagie et amorce la ferroptose dans les cellules cancéreuses pancréatiques

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Myoferlin contributes to the metastatic phenotype of pancreatic cancer cells by enhancing their migratory capacity through the control of oxidative phosphorylation

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies with an overall survival of 5%, and is the second cause of death by cancer, mainly linked to its high metastatic aggressiveness. Accordingly, understanding the mechanisms sustaining the PDAC metastatic phenotype remains a priority. In this study, we have generated and used a murine in vivo model to select clones from the human PANC-1 PDAC cell line that exhibit a high propensity to seed and metastasized into the liver. We showed that myoferlin, a protein previously reported to be overexpressed in PDAC, is significantly involved in the migratory abilities of the selected cells. We first report that highly PANC-1 metastatic clones expressed significantly higher myoferlin level than the corresponding low metastatic ones. Using scratch wound and Boyden’s chamber assays, we show that cells expressing high myoferlin level have higher migratory potential than cells characterized by a low myoferlin abundance. Moreover, we demonstrate that myoferlin silencing leads to a migration decrease associated to a reduction of mitochondrial respiration. Since mitochondrial oxidative phosphorylation has been shown to be implicated in the tumor progression and dissemination, our data identify myoferlin as a valid potential therapeutic target in PDAC

Resistance to Gemcitabine in Pancreatic Cancer Is Connected to Methylglyoxal Stress and Heat Shock Response

peer reviewedPancreatic ductal adenocarcinoma (PDAC) is a fatal disease with poor prognosis. Gemcitabine is the first-line therapy for PDAC, but gemcitabine resistance is a major impediment to achieving satisfactory clinical outcomes. This study investigated whether methylglyoxal (MG), an oncometabolite spontaneously formed as a by-product of glycolysis, notably favors PDAC resistance to gemcitabine. We observed that human PDAC tumors expressing elevated levels of glycolytic enzymes together with high levels of glyoxalase 1 (GLO1), the major MG-detoxifying enzyme, present with a poor prognosis. Next, we showed that glycolysis and subsequent MG stress are triggered in PDAC cells rendered resistant to gemcitabine when compared with parental cells. In fact, acquired resistance, following short and long-term gemcitabine challenges, correlated with the upregulation of GLUT1, LDHA, GLO1, and the accumulation of MG protein adducts. We showed that MG-mediated activation of heat shock response is, at least in part, the molecular mechanism underlying survival in gemcitabine-treated PDAC cells. This novel adverse effect of gemcitabine, i.e., induction of MG stress and HSR activation, is efficiently reversed using potent MG scavengers such as metformin and aminoguanidine. We propose that the MG blockade could be exploited to resensitize resistant PDAC tumors and to improve patient outcomes using gemcitabine therapy

Myoferlin targeting triggers mitophagy and primes ferroptosis in pancreatic cancer cells

Myoferlin, an emerging oncoprotein, has been associated with a low survival in several cancer types including pancreas ductal adenocarcinoma where it controls mitochondria structure and respiratory functions. Owing to the high susceptibility of KRAS-mutated cancer cells to iron-dependent cell death, ferroptosis, and to the high iron content in mitochondria, we investigated the relation existing between mitochondrial integrity and iron-dependent cell death. We discovered that myoferlin targeting with WJ460 pharmacological compound triggered mitophagy and ROS accumulation culminating with lipid peroxidation and apoptosis-independent cell death. WJ460 caused a reduction of the abundance of ferroptosis core regulators xc- cystine/glutamate transporter and GPX-4. Mitophagy inhibitor Mdivi1 and iron chelators inhibited the myoferlin-related ROS production and restored cell growth. Additionally, we reported a synergic effect between ferroptosis inducers, erastin and RSL3, and WJ460

Expression of Bone Sialoprotein in Human Lung Cancer

Lung cancer belongs to the group of malignant lesions that specifically select bone as secondary implantation site. The molecular bases for this property, defined as osteotropism, is still largely unknown. The recent demonstration that human breast cancer cells express and attach to bone sialoprotein (BSP), a sulfated phosphoprotein rich in bone and other mineralized tissues, could provide a clue to elucidating bone metastases formation. BSP contains the integrin binding peptide Arg-Gly-Asp (RGD), as well as non-RGD cell attachment domain. Using an immunoperoxidase technique and a specific polyclonal antibody directed against a BSP synthetic peptide, we examined the expression of BSP in 48 lung lesions including 25 squamous carcinoma, 21 adenocarcinoma, and 2 bronchioloalveolar cancers, as well as 38 human ovarian carcinoma that constitute a group of generally nonosteotropic cancers. BSP was not specifically detected in normal lung tissue with the exception of cartilage associated with bronchi. Most of the adenocarcinoma (74%) and all squamous carcinoma of the lung examined exhibited detectable levels of BSP. Staining was mainly cytoplasmic and membrane associated. The two bronchioloalveolar lung cancers examined did not show detectable amounts of BSP. When microcalcifications were observed in pulmonary malignant lesions, they were usually associated with cancer cells expressing BSP. Only 21% of the ovarian cancers examined contained malignant cells with 2+ or 3+ positivity for BSP. We further demonstrated that in 8 of 10 additional lung cancers, BSP was detected at the mRNA level. Our observation is the first demonstration that BSP is expressed in non-small cell lung carcinoma. Lung cancer cells are now the second type of osteotropic malignant cells described to express BSP. Added to the observation that BSP expression is not frequent in ovarian carcinoma, a low osteotropic cancer, our study supports our hypothesis that BSP could play a role in determining the affinity of cancer cells to bone

Improving pancreatic cancer response to gemcitabine by overcoming methylglyoxal driven suppression of AMPK

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