Pepsin enhances glycolysis to promote malignant transformation of vocal fold leukoplakia epithelial cells with dysplasia.

PURPOSE: The mechanism underlying malignant transformation of vocal fold leukoplakia (VFL) and the precise role of the expression of pepsin in VFL remain unclear. This study aimed to investigate the effects of acidified pepsin on VFL epithelial cell growth and migration, and also identify pertinent molecular mechanisms. METHODS: Immunochemistry and Western blotting were performed to measure glucose transporter type 1 (GLUT1), monocarboxylate transporters 4 (MCT4), and Hexokinase-II (HK-II) expressions. Cell viability, cell cycle, apoptosis, and migration were investigated by CCK-8 assay, flow cytometry and Transwell chamber assay, respectively. Glycolysis-related contents were determined using the corresponding kits. Mitochondrial HK-II was photographed under a confocal microscope using Mito-Tracker Red. RESULTS: It was found: the expression of pepsin and proportion of pepsin+ cells in VFL increased with the increased dysplasia grade; acidified pepsin enhanced cell growth and migration capabilities of VFL epithelial cells, reduced mitochondrial respiratory chain complex I activity and oxidative phosphorylation, and enhanced aerobic glycolysis and GLUT1 expression in VFL epithelial cells; along with the transfection of GLUT1 overexpression plasmid, 18FFDG uptake, lactate secretion and growth and migration capabilities of VFL epithelial cell were increased; this effect was partially blocked by the glycolysis inhibitor 2-deoxy-glucose; acidified pepsin increased the expression of HK-II and enhanced its distribution in mitochondria of VFL epithelial cells. CONCLUSION: It was concluded that acidified pepsin enhances VFL epithelial cell growth and migration abilities by reducing mitochondrial respiratory complex I activity and promoting metabolic reprogramming from oxidative phosphorylation to aerobic glycolysis.

Mitochondrial Voltage-Dependent Anion Channel 1-Hexokinase-II Complex-Targeted Strategy for Melanoma Inhibition Using Designed Multiblock Peptide Amphiphiles.

Targeted therapies of melanoma are of urgent need considering the resistance of this aggressive type of cancer to chemotherapeutics. The voltage-dependent anion channel 1 (VDAC1)-hexokinase-II (HK-II) complex is an emerging target for novel anticancer therapies based on induced mitochondria-mediated apoptosis. The low cell membrane permeability of the anticancer 12-mer peptide N-Ter (RDVFTKGYGFGL) derived from the N-terminal fragment of the VDAC1 protein impedes the intracellular targeting. Here, novel multiblock VDAC1-derived cationic amphiphilic peptides (referred to as Pal-N-Ter-TAT, pFL-N-Ter-TAT, and Pal-pFL-N-Ter-TAT) are designed with a self-assembly propensity and cell-penetrating properties. The created multiblock amphiphilic peptides of partial α-helical conformations form nanoparticles of ellipsoid-like shapes and are characterized by enhanced cellular uptake. The amphiphilic peptides can target mitochondria and dissociate the VDAC1-HK-II complex at the outer mitochondrial membrane, which result in mitochondria-mediated apoptosis. The latter is associated with decrease of the mitochondrial membrane potential, cytochrome c release, and changes of the expression levels of the apoptotic proteins in A375 melanoma cells. Importantly, the mitochondrial VDAC1-derived amphiphilic peptides have a comparable IC50 value for melanoma cells to a small-molecule drug, sorafenib, which has been previously used in clinical trials for melanoma. These results demonstrate the potential of the designed peptide constructs for efficient melanoma inhibition.

Regulation of Glycolysis in Head and Neck Cancer.

Head and neck squamous cell carcinoma (HNSCC) glycolysis is an important factor for the advancement of the disease and metastasis. Upregulation of glycolysis leads to decreased sensitivity to chemotherapy and radiation. HNSCC cells maintain constitutive glycolytic flux generating metabolic intermediates for the synthesis of amino acids, nucleotides, and fats for cell survival and disease progression. There are several pathways such as PI3K/Akt, EGFR, and JAK-STAT that contribute a major role in metabolic alteration in HNSCC. Recent studies have demonstrated that cancer-associated fibroblasts abundant in the HNSCC tumor microenvironment play a major role in HNSCC metabolic alteration via hepatocyte growth factor (HGF)/c-Met cross signaling. Despite therapeutic advancement, HNSCC lacks broad range of therapeutic interventions for the treatment of the disease. Thus, understanding the different key players involved in glucose metabolism and targeting them would lead to the development of novel drugs for the treatment of HNSCC.

True hypopharyngeal carcinosarcoma: a case report and literature review.

Objective Carcinosarcoma consists of carcinomatous and sarcomatous tissues and is an aggressive malignant tumor. It is rarely reported in the hypopharynx. Methods A 72-year-old man presented with dysphagia and dyspnea. Laryngoscopy, computed tomography (CT), and 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET/CT) showed a neoplasm on the left posterior hypopharyngeal wall. The patient underwent bilateral neck dissection and excision of the hypopharyngeal cancer followed by postoperative radiation therapy. Results Immunohistochemistry revealed carcinomatous cells with membrane positivity for cytokeratin, glucose transporter-1 (GLUT-1), phosphoinositide-3 kinase (PI3K), hypoxia-inducible factor-1α (HIF-1α), and hexokinase-II as well as sarcomatous cells with membrane positivity for smooth muscle actin, GLUT-1, HIF-1α, and PI3K. Histopathology and immunohistochemistry revealed a true carcinosarcoma of the hypopharynx (pT3N0M0, Stage III). Conclusions Thorough immunohistochemistry is required for a correct diagnosis of hypopharyngeal carcinosarcoma. 18F-FDG PET/CT may help to distinguish hypopharyngeal carcinosarcoma from benign tumors.

Effect of HK2, PKM2 and LDHA on Cetuximab efficacy in metastatic colorectal cancer.

Although hexokinase (HK) 2, pyruvate kinase muscle (PKM) isozyme 2 and lactate dehydrogenase (LDH) A predict the efficacy of medicines in various solid tumors, their ability to predict the efficacy of cetuximab in metastatic colorectal cancer (mCRC) remains unclear. mCRC patients with pathological specimens who received cetuximab and chemotherapy from 2005 to 2015 in the present institution were enrolled. Immunohistochemistry was used to detect HK2, PKM2 and LDHA expression. SPSS20 was used for statistical analysis. A total of 68 patients were included; 33 received cetuximab plus chemotherapy as first-line therapy, and the rest, as second- or later-line therapy. HK2 expression levels were increased in cancer compared with normal tissue (75.4% vs. 40%; P<0.001), however PKM2 (P=0.243) and LDHA (P=0.067) expression levels were not. For progression-free survival (PFS) with first-line cetuximab plus chemotherapy, patients with high HK2 expression exhibited longer PFS compared with those with low HK2 expression (23.9 months vs. 6.9 months; P=0.021). However, this positive association was absent in 35 cases administered first-line chemotherapy alone (13.4 months vs. 13.5 months; P=0.539). LDHA expression was associated with the PFS of patients receiving first-line chemotherapy (18.3 and 10.1 months for high and low expression, respectively; P=0.005), whereas this association was absent in cetuximab plus chemotherapy cases (19.9 months vs. 12 months; P=0.522). Furthermore, high LDHA expression correlated with high overall response rate (ORR) (72.2% vs. 15.4%, P=0.006) for chemotherapy, however not disease control rate (DCR) (P=0.074). Neither DCR nor ORR were associated with HK2 expression. PKM2 expression did not affect PFS, DCR or ORR. LDHA expression (P=0.005), pathological differentiation (P=0.019) and synchronous/metachronous metastasis (P=0.014) were independent predictive factors of PFS for all first-line patients, and tumor differentiation (P=0.002) was associated with overall survival (OS) in multivariate analysis. HK2, PKM2 and LDHA did not impact OS. It was concluded that HK2 expression was increased in colorectal cancer tissue and may predict cetuximab efficacy and LDHA for chemotherapy treatment of mCRC.

Regulation of glycolysis in head and neck squamous cell carcinoma.

Glycolysis is highly upregulated in head and neck squamous cell carcinoma (HNSCC). HNSCC glycolysis is an important contributor to disease progression and decreases sensitivity to radiation or chemotherapy. Despite therapeutic advances, the survival rates for HNSCC patients remain low. Understanding glycolysis regulation in HNSCC will facilitate the development of effective therapeutic strategies for this disease. In this review, we will evaluate the regulation of altered HNSCC glycolysis and possible therapeutic approaches by targeting glycolytic pathways.

Dynamic changes in the main regulatory genes of mitochondrial permeability transition pore in Eimeria tenella host cells.

The purpose of the present study was to investigate the dynamic changes in the main regulatory genes of the mitochondrial permeability transition pore in E. tenella host cells. Primary chick embryo cecum epithelial cell culture techniques, spectrophotometer technology, Hoechst-Annexin V-PI apoptosis staining and ELISA were used to detect the apoptosis rate and dynamic changes of Bcl-2, Bcl-xl, Bax, Bak, Bid, Bad, HK-II, and ATP content in E. tenella host cells at 4, 24, 48, 72, 96, and 120 h. The rates of early apoptosis, late apoptosis, and necrosis of group T0 were significantly lower (P < 0.05) or highly significantly lower (P < 0.01) than those of group C at 4 h, but higher (P < 0.05 or P < 0.01) at varying degrees than those of the same group at 24-120 h. Compared to group C, the amount of Bcl-2, ATP, Bax and Bad in group T0 were visibly lower (P < 0.05 or P < 0.01) at 4 h, whereas Bcl-xl/Bax was highly significantly higher (P < 0.01) at 4 h. In addition, group T0 had less ATP at 24-120 h than group C, whereas the amount of Bcl-2, Bcl-xl, Bax, Bak, Bid, Bad and HK-II in group T0 inversely increased in varying degrees at 24-120 h compared with group C. Moreover, Bcl-2/Bax was lower (P < 0.01) at 24, 48, and 96 h, and Bcl-xl/Bax was lower (P < 0.05) at 48 h in group T0 than in group C, respectively. Taken together, these observations indicate that in the early developmental stages of E. tenella, the host-cell apoptosis rate decreased; although the amount of anti- and pro-apoptotic genes in host cells decreased, the ratios of anti-apoptotic to pro-apoptotic bcl-2 gene-family members increased. In the middle and later developmental stages of E. tenella, the host-cell apoptosis rate increased; the amount of anti- and pro-apoptotic genes increased, while the ratios of anti-apoptotic to pro-apoptotic bcl-2 gene-family members decreased. In addition, ATP decreased at all developmental stages of E. tenella.

Long-term prognostic implications and therapeutic target role of hexokinase II in patients with nasopharyngeal carcinoma.

Tumor cells preferentially use anaerobic glycolysis rather than oxidative phosphorylation to generate energy. Hexokinase II (HK-II) is necessary for anaerobic glycolysis and displays aberrant expression in malignant cells. The current study aimed to evaluate the role of HK-II in the survival and biological function of nasopharyngeal carcinoma (NPC). Our study demonstrated that high expression of HK-II was associated with poor survival outcomes in NPC patients. When using 3-BrOP (an HK-II inhibitor) to repress glycolysis, cell proliferation and invasion were attenuated, accompanied by the induction of apoptosis and cell cycle arrest at the G1 stage. Furthermore, 3-BrOP synergized with cisplatin (DDP) to induce NPC cell death. Collectively, we provided that the aberrant expression of HK-II was associated with the malignant phenotype of NPC. A combined treatment modality that targets glycolysis with DDP holds promise for the treatment of NPC patients.

Light activation of the insulin receptor regulates mitochondrial hexokinase. A possible mechanism of retinal neuroprotection.

The serine/threonine kinase Akt has been shown to mediate the anti-apoptotic activity through hexokinase (HK)-mitochondria interaction. We previously reported that Akt activation in retinal rod photoreceptor cells is mediated through the light-dependent insulin receptor (IR)/PI3K pathway. Our data indicate that light-induced activation of IR/PI3K/Akt results in the translocation of HK-II to mitochondria. We also found that PHLPPL, a serine/threonine phosphatase, enhanced the binding of HK-II to mitochondria. We found a mitochondrial targeting signal in PHLPPL and our study suggests that Akt translocation to mitochondria could be mediated through PHLPPL. Our results suggest that the light-dependent IR/PI3K/Akt pathway regulates hexokinase-mitochondria interaction in photoreceptors. Down-regulation of IR signaling has been associated with ocular diseases of retinitis pigmentosa, diabetic retinopathy, and Leber Congenital Amaurosis-type 2, and agents that enhance the binding interaction between hexokinase and mitochondria may have therapeutic potential against these ocular diseases.