Enhanced TKTL1 Expression in Malignant Tumors of the Ocular Adnexa Predicts Clinical Outcome

Ocular surface squamous neoplasia: Update on genetics, epigenetics and opportunities for targeted therapy

PURPOSE

The purpose of this review is to explore the molecular foundations of ocular surface squamous neoplasia (OSSN), focusing on the genetic and epigenetic aspects. While current management strategies include surgical excision and medical therapies, the understanding of OSSN's molecular basis remains limited, hindering the development of targeted treatments.

METHODS

A comprehensive MEDLINE search was conducted for literature published between January 1993 and October 2023. Only studies with original data on molecular, genetic, or epigenetic mechanisms, such as mutations, gene expression, and genetic predispositions were included. Articles were excluded if they focused solely on clinical management without addressing these factors, or if they were reviews, editorials, or opinion pieces.

RESULTS

The search yielded a total of 108 articles, out of which 39 articles met the criteria for further analysis. Investigations into OSSN have identified key DNA mutations in the TP53, HGF, EGFR, TERT, and CDKN2A genes, indicating common oncogenic pathways shared with other squamous cell carcinomas (SCCs). Significant epigenetic changes were identified, including DNA methylation, histone modifications, and altered miRNA expression patterns. Epigenetic dysregulation of critical tumor suppressors and oncoproteins, further highlight the complex genetic landscape of OSSN.

CONCLUSION

The molecular alterations identified in OSSN not only enhance our understanding of its biology but also have potential as novel biomarkers for early detection, prognostic evaluation, and as therapeutic targets. The identification of genetic and epigenetic markers in OSSN signifies progress towards personalized medicine approaches. Further studies and collaborative efforts are essential to validate these molecular markers and translate them into clinical practice, potentially revolutionizing OSSN management and improving patient outcomes.

Prognostic Biomarkers for Hepatocellular Carcinoma Based on Serine and Glycine Metabolism-related Genes

Background and Aims

Targeted therapy and immunotherapy have emerged as treatment options for hepatocellular carcinoma (HCC) in recent years. The significance of serine and glycine metabolism in various cancers is widely acknowledged. This study aims to investigate their correlation with the prognosis and tumor immune microenvironment (TIME) of HCC.

Methods

Based on the public database, different subtypes were identified by cluster analysis, and the prognostic model was constructed through regression analysis. The gene expression omnibus (GEO) data set was used as the validation set to verify the performance of the model. The survival curve evaluated prognostic ability. CIBERSORT was used to evaluate the level of immune cell infiltration, and maftools analyzed the mutations. DsigDB screened small molecule compounds related to prognostic genes.

Results

HCC was found to have two distinct subtypes. Subsequently, we constructed a risk score prognostic model through regression analysis based on serine and glycine metabolism-related genes (SGMGs). A nomogram was constructed based on risk scores and other clinical factors. HCC patients with a higher risk score showed a poor prognosis, and there were significant differences in immune cell infiltration between the high- and low-risk groups. In addition, three potential drugs associated with prognostic genes, streptozocin, norfloxacin, and hydrocotarnine, were identified.

Conclusions

This study investigated the expression patterns of SGMGs and their relationship with tumor characteristics, resulting in the development of a novel model for predicting the prognosis of HCC patients. The study provides a reference for clinical prognosis prediction and treatment of HCC patients.

Metabolic signatures in pancreatic ductal adenocarcinoma: diagnostic and therapeutic implications

Pancreatic ductal adenocarcinoma (PDAC) is the prototypical aggressive cancer that develops in nutrient-deficient and hypoxic microenvironment. PDAC overcomes these restrictions by employing unconventional tactics for the procurement and usage of fuel sources. The substantial reprogramming of PDAC cell metabolism is driven by oncogene-mediated cell-autonomous pathways. PDAC cells use glucose, glutamine, and lipids for energy and depend on autophagy and macropinocytosis for survival and growth. They also interact metabolically with non-cancerous cells, aiding tumor progression. Many clinical trials focusing on altered metabolism are ongoing. Understanding the metabolic regulation of PDAC cells will not only help to increase understanding of the mechanisms of disease progression but also provide insights for the development of new diagnostic and therapeutic approaches.

Bindehautdegenerationen und -neoplasien

Erhabenheiten der Bindehaut entstehen durch Gewebevermehrung, die entweder degenerativ oder neoplastisch, aber auch entzündlich sein können. In diesem Artikel werden degenerative (Pterygium und Pinguecula) sowie benigne und maligne neoplastische Bindehautveränderungen (epitheliale, melanozytäre und vaskuläre Tumoren, Choristome sowie Metastasen) bezüglich der Pathogenese, Symptome, Diagnostik und aktuellem Stand der Behandlung dargestellt.

[Conjunctival Degeneration and Neoplasia]

Conjunctival tumors result from gain of tissue, which can be either degenerative or neoplastic, but also inflammatory. In this article, degenerative (pterygium and pinguecula) as well as benign and malignant neoplastic conjunctival changes (epithelial, melanocytic and vascular tumors, choristomas as well as metastases) are discussed with regard to pathogenesis, symptoms, diagnostics and current status of treatment.

Pterygium and Ocular Surface Squamous Neoplasia: Optical Biopsy Using a Novel Autofluorescence Multispectral Imaging Technique

In this study, differentiation of pterygium vs. ocular surface squamous neoplasia based on multispectral autofluorescence imaging technique was investigated. Fifty (N = 50) patients with histopathological diagnosis of pterygium (PTG) and/or ocular surface squamous neoplasia (OSSN) were recruited. Fixed unstained biopsy specimens were imaged by multispectral microscopy. Tissue autofluorescence images were obtained with a custom-built fluorescent microscope with 59 spectral channels, each with specific excitation and emission wavelength ranges, suitable for the most abundant tissue fluorophores such as elastin, flavins, porphyrin, and lipofuscin. Images were analyzed using a new classification framework called fused-classification, designed to minimize interpatient variability, as an established support vector machine learning method. Normal, PTG, and OSSN regions were automatically detected and delineated, with accuracy evaluated against expert assessment by a specialist in OSSN pathology. Signals from spectral channels yielding signals from elastin, flavins, porphyrin, and lipofuscin were significantly different between regions classified as normal, PTG, and OSSN (p < 0.01). Differential diagnosis of PTG/OSSN and normal tissue had accuracy, sensitivity, and specificity of 88 ± 6%, 84 ± 10% and 91 ± 6%, respectively. Our automated diagnostic method generated maps of the reasonably well circumscribed normal/PTG and OSSN interface. PTG and OSSN margins identified by our automated analysis were in close agreement with the margins found in the H&E sections. Such a map can be rapidly generated on a real time basis and potentially used for intraoperative assessment.

Characterization of the Cellular Microenvironment and Novel Specific Biomarkers in Pterygia Using RNA Sequencing

With a worldwide prevalence of ~12%, pterygium is a common degenerative and environmentally triggered ocular surface disorder characterized by wing-shaped growth of conjunctival tissue onto the cornea that can lead to blindness if left untreated. This study characterizes the transcriptional profile and the cellular microenvironment of conjunctival pterygia and identifies novel pterygia-specific biomarkers. Formalin-fixed and paraffin-embedded pterygia as well as healthy conjunctival specimens were analyzed using MACE RNA sequencing (n = 8 each) and immunohistochemistry (pterygia n = 7, control n = 3). According to the bioinformatic cell type enrichment analysis using xCell, the cellular microenvironment of pterygia was characterized by an enrichment of myofibroblasts, T-lymphocytes and various antigen-presenting cells, including dendritic cells and macrophages. Differentially expressed genes that were increased in pterygia compared to control tissue were mainly involved in autophagy (including DCN, TMBIM6), cellular response to stress (including TPT1, DDX5) as well as fibroblast proliferation and epithelial to mesenchymal transition (including CTNNB1, TGFBR1, and FN1). Immunohistochemical analysis confirmed a significantly increased FN1 stromal immunoreactivity in pterygia when compared to control tissue. In addition, a variety of factors involved in apoptosis were significantly downregulated in pterygia, including LCN2, CTSD, and NISCH. Furthermore, 450 pterygia-specific biomarkers were identified by including transcriptional data of different ocular surface pathologies serving as controls (training group), which were then validated using transcriptional data of cultured human pterygium cells. Among the most pterygia-specific factors were transcripts such as AHNAK, RTN4, TPT1, FSTL1, and SPARC. Immunohistochemical validation of SPARC revealed a significantly increased stromal immunoreactivity in pterygia when compared to controls, most notably in vessels and intravascular vessel wall-adherent mononuclear cells. Taken together, the present study provides new insights into the cellular microenvironment and the transcriptional profile of pterygia, identifies new and specific biomarkers and in addition to fibrosis-related genes, uncovers autophagy, stress response and apoptosis modulation as pterygium-associated processes. These findings expand our understanding of the pathophysiology of pterygia, provide new diagnostic tools, and may enable new targeted therapeutic options for this common and sight-threatening ocular surface disease.

MACE RNA sequencing analysis of conjunctival squamous cell carcinoma and papilloma using formalin-fixed paraffin-embedded tumor tissue

Recent advances in the field of biomedical research allow for elucidation of the transcriptional signature of rare tumors such as conjunctival squamous cell carcinoma (SCC). In this study we compare its expression profile to conjunctival papilloma (Pap) and healthy conjunctival tissue (Ctrl) and develop a classification tool to differentiate these entities. Seven conjunctival SCC, seven Pap and ten Ctrl were formalin-fixed and paraffin-embedded (FFPE) and analyzed using Massive Analysis of cDNA Ends (MACE) RNA sequencing. Differentially expressed genes (DEG) and gene ontology (GO) clusters were explored and the abundance of involved cell types was quantified by xCell. Finally, a classification model was developed to distinguish SCC from Pap and Ctrl. Among the most prominent DEG in SCC a plethora of keratins were upregulated when compared to Pap and Ctrl. xCell analysis revealed an enrichment of immune cells, including activated dendritic cells and T-helper type 1 cells (Th1), in SCC when compared to Ctrl. The generated classification model could reliably discriminate between the three entities according to the expression pattern of 30 factors. This study provides a transcriptome-wide gene expression profile of rare conjunctival SCC. The analysis identifies distinct keratins, as well as dendritic and Th1 cells as important mediators in SCC. Finally, the provided gene expression classifier may become an aid to the conventional histological classification of conjunctival tumors in uncertain cases.

TKTL1 as a Prognostic Marker in Pancreatic Ductal Adenocarcinoma and Its Correlation with FDG-PET-CT

INTRODUCTION

Glucose metabolism in cancer cells differs from noncancerous cells. The expression of transketolase-like protein 1 (TKTL1), a key enzyme in the glucose metabolism of cancer cells, predicts poor prognosis in several cancer types. We studied TKTL1 as a prognostic tool and whether TKTL1 expression correlates with 18F-FDG-PET-CT among patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

This retrospective study examined two PDAC patient cohorts: 168 patients operated on at Helsinki University Hospital between 2001 and 2011, and 20 patients with FDG-PET-CT results available from the Auria Biobank. We used immunohistochemistry for TKTL1 expression, combining results with clinicopathological data.

RESULTS

Five-year disease-specific survival (DSS) was slightly but not significantly better in patients with a high versus low TKTL1 expression, with DSS of 28.0 versus 17.3%, respectively (p = 0.123). TKTL1 served as a marker of a better prognosis in patients over 65 years old (p = 0.012) and among those with TNM class M1 (p = 0.018), stage IV disease (p = 0.027), or perivascular invasion (p = 0.008).

CONCLUSIONS

Our study shows that TKTL1 cannot be used as a prognostic factor in PDAC with the exception of elderly patients and those with advanced disease. The correlation of TKTL1 with 18F-FDG-PET-CT requires further study in a larger patient cohort.

Transcriptional characterization of conjunctival melanoma identifies the cellular tumor microenvironment and prognostic gene signatures

This study characterizes the transcriptome and the cellular tumor microenvironment (TME) of conjunctival melanoma (CM) and identifies prognostically relevant biomarkers. 12 formalin-fixed and paraffin-embedded CM were analyzed by MACE RNA sequencing, including six cases each with good or poor clinical outcome, the latter being defined by local recurrence and/or systemic metastases. Eight healthy conjunctival specimens served as controls. The TME of CM, as determined by bioinformatic cell type enrichment analysis, was characterized by the enrichment of melanocytes, pericytes and especially various immune cell types, such as plasmacytoid dendritic cells, natural killer T cells, B cells and mast cells. Differentially expressed genes between CM and control were mainly involved in inhibition of apoptosis, proteolysis and response to growth factors. POU3F3, BIRC5 and 7 were among the top expressed genes associated with inhibition of apoptosis. 20 genes, among them CENPK, INHA, USP33, CASP3, SNORA73B, AAR2, SNRNP48 and GPN1, were identified as prognostically relevant factors reaching high classification accuracy (area under the curve: 1.0). The present study provides new insights into the TME and the transcriptional profile of CM and additionally identifies new prognostic biomarkers. These results add new diagnostic tools and may lead to new options of targeted therapy for CM.

3' MACE RNA-sequencing allows for transcriptome profiling in human tissue samples after long-term storage

This study aims to compare the potential of standard RNA-sequencing (RNA-Seq) and 3' massive analysis of c-DNA ends (MACE) RNA-sequencing for the analysis of fresh tissue and describes transcriptome profiling of formalin-fixed paraffin-embedded (FFPE) archival human samples by MACE. To compare MACE to standard RNA-Seq on fresh tissue, four healthy conjunctiva from four subjects were collected during vitreoretinal surgery, halved and immediately transferred to RNA lysis buffer without prior fixation and then processed for either standard RNA-Seq or MACE RNA-Seq analysis. To assess the impact of FFPE preparation on MACE, a third part was fixed in formalin and processed for paraffin embedding, and its transcriptional profile was compared with the unfixed specimens analyzed by MACE. To investigate the impact of FFPE storage time on MACE results, 24 FFPE-treated conjunctival samples from 24 patients were analyzed as well. Nineteen thousand six hundred fifty-nine transcribed genes were detected by both MACE and standard RNA-Seq on fresh tissue, while 3251 and 2213 transcripts were identified explicitly by MACE or RNA-Seq, respectively. Standard RNA-Seq tended to yield longer detected transcripts more often than MACE technology despite normalization, indicating that the MACE technology is less susceptible to a length bias. FFPE processing revealed negligible effects on MACE sequencing results. Several quality-control measurements showed that long-term storage in paraffin did not decrease the diversity of MACE libraries. We noted a nonlinear relation between storage time and the number of raw reads with an accelerated decrease within the first 1000 days in paraffin, while the numbers remained relatively stable in older samples. Interestingly, the number of transcribed genes detected was independent on FFPE storage time. RNA of sufficient quality and quantity can be extracted from FFPE samples to obtain comprehensive transcriptome profiling using MACE technology. We thus present MACE as a novel opportunity for utilizing FFPE samples stored in histological archives.

High TKTL1 expression as a sign of poor prognosis in colorectal cancer with synchronous rather than metachronous liver metastases

Colorectal cancer (CRC) is the third most common cancer in the world. More than half of all affected patients develop liver metastases during the course of the disease, and over half experience recurrence despite radical primary surgery. Transketolase-like protein 1 (TKTL1) is a key enzyme in the glucose metabolism of cancer cells, and its expression in tumor tissue was previously shown to indicate a poor prognosis in colorectal cancer. In this study, we investigated the prognostic significance of TKTL1 in 111 patients with surgically resected colorectal liver metastases, with a minimum follow-up time of 10.3 years. TKTL1 expression was examined in tissue samples of both primary tumors and liver metastases, and compared to clinicopathological parameters, disease-free survival, and overall survival. We show that a high expression of TKTL1 in primary tumor tissue associated with poor disease-free survival in patients with synchronous liver metastases (P = .026, Kaplan-Meier log-rank test), but with better disease-free survival in patients with metachronous metastases, although not statistically significantly (P = .073). We found similar tendencies for TKTL1 expression in liver metastases. Thus, TKTL1 could serve as a candidate marker to identify patients who benefit from liver resection or who need more aggressive perioperative chemotherapy.

Expression of the COVID-19 receptor ACE2 in the human conjunctiva

SARS‐CoV‐2 is assumed to use angiotensin‐converting enzyme 2 (ACE2) and other auxiliary proteins for cell entry. Recent studies have described conjunctival congestion in 0.8% of patients with laboratory‐confirmed severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2), and there has been speculation that SARS‐CoV‐2 can be transmitted through the conjunctiva. However, it is currently unclear whether conjunctival epithelial cells express ACE2 and its cofactors. In this study, a total of 38 conjunctival samples from 38 patients, including 12 healthy conjunctivas, 12 melanomas, seven squamous cell carcinomas, and seven papilloma samples, were analyzed using high‐throughput RNA sequencing to assess messenger RNA (mRNA) expression of the SARS‐CoV‐2 receptor ACE2 and its cofactors including TMPRSS2, ANPEP, DPP4, and ENPEP. ACE2 protein expression was assessed in eight healthy conjunctival samples using immunohistochemistry. Our results show that the SARS‐CoV‐2 receptor ACE2 is not substantially expressed in conjunctival samples on the mRNA (median: 0.0 transcripts per million [TPM], min: 0.0 TPM, max: 1.7 TPM) and protein levels. Similar results were obtained for the transcription of other auxiliary molecules. In conclusion, this study finds no evidence for a significant expression of ACE2 and its auxiliary mediators for cell entry in conjunctival samples, making conjunctival infection with SARS‐CoV‐2 via these mediators unlikely.

HIF-1α, HIF-2α, and ProExC: diagnostic or prognostic relevance in conjunctival intraepithelial neoplasia?

Purpose

The aim of this study was to investigate HIF-1α, HIF-2α, and ProExC expression in conjunctival intraepithelial neoplasia (CIN), to differentiate between metaplasia and dysplasia, and to access their value as diagnostic and prognostic immunohistochemical markers. Recurrence and progression into SCC (squamous cell carcinoma) were defined as endpoints.

Methods

Forty-three specimens including CIN I (2), CIN II (9), CIN III (29), with and without metaplasia, and metaplasia alone (3), as well as 21 conjunctival control specimens, were stained with antibodies against HIF-1α, HIF-2α, and ProExC. The percentage of positively stained cells were calculated and used for further analysis.

Results

The mean percentages of HIF-1α and HIF-2α were not increased in CIN. In comparison, the expressions of these markers were even significantly elevated in control specimens (p < 0.001). Upper epithelial cells in CIN were more often ProExC-positive compared with normal conjunctiva or metaplasia (p = 0.06 and p = 0.07). Cox proportional-hazards analysis was performed for characterization of factors influencing the combined endpoint and showed a significant elevated hazard ratio for staining with ProExC (p = 0.04) compared with HIF-1α (p = 0.26) and HIF-2α (p = 0.49).

Conclusion

Our study shows that HIF-1α and HIF-2α do not serve as diagnostic or prognostic markers in CIN. ProExC seems to be a potential indicator for CIN, but not a reliable diagnostic marker. However, control specimens occasionally also display a high percentage of ProExC-positive cells and staining over the entire epithelial layer.

Transketolase-Like Protein 1 and Glucose Transporter 1 in Gastric Cancer

BACKGROUND

The glucose metabolism of cancer cells differs from that of noncancerous cells. Transketolase-like protein 1 (TKTL1) and glucose transporter 1 (GLUT1) both play a role in this process. These biochemical tumor markers are overexpressed in several types of human cancer.

OBJECTIVE

We sought to determine if TKTL1 and/or GLUT1 expression predicts prognosis in gastric cancer.

METHODS

In this retrospective study, we selected 284 patients who underwent surgery for gastric cancer at the Helsinki University Hospital. We used immunohistochemistry to assess the expression of TKTL1 and GLUT1, combined with clinicopathological data.

RESULTS

Positive expression of TKTL1 was associated with positive expression of GLUT1, age over 65 years, male gender, advanced stage (II-IV), and advanced tumors (T2-T4). Patients with a positive expression of TKTL1 had a poorer prognosis than those with no expression (p = 0.042, Breslow test). GLUT1 positivity was associated with higher age and with the intestinal type of gastric cancer but did not carry any prognostic value.

CONCLUSION

In conclusion, our study showed that positive expression of TKTL1 correlates with a poor prognosis in gastric cancer.

APC/CCDH1 synchronizes ribose-5-phosphate levels and DNA synthesis to cell cycle progression

Accumulation of nucleotide building blocks prior to and during S phase facilitates DNA duplication. Herein, we find that the anaphase-promoting complex/cyclosome (APC/C) synchronizes ribose-5-phosphate levels and DNA synthesis during the cell cycle. In late G₁ and S phases, transketolase-like 1 (TKTL1) is overexpressed and forms stable TKTL1-transketolase heterodimers that accumulate ribose-5-phosphate. This accumulation occurs by asymmetric production of ribose-5-phosphate from the non-oxidative pentose phosphate pathway and prevention of ribose-5-phosphate removal by depleting transketolase homodimers. In the G₂ and M phases after DNA synthesis, expression of the APC/C adaptor CDH1 allows APC/C^CDH1 to degrade D-box-containing TKTL1, abrogating ribose-5-phosphate accumulation by TKTL1. TKTL1-overexpressing cancer cells exhibit elevated ribose-5-phosphate levels. The low CDH1 or high TKTL1-induced accumulation of ribose-5-phosphate facilitates nucleotide and DNA synthesis as well as cell cycle progression in a ribose-5-phosphate-saturable manner. Here we reveal that the cell cycle control machinery regulates DNA synthesis by mediating ribose-5-phosphate sufficiency.

Ribose-5-phosphate (R5P) is required for DNA synthesis, but how this is regulated during cell cycle progression is unclear. Here the authors report that the cell cycle regulator APC/C-CDH1 synchronizes cell cycle progression with R5P-derived DNA synthesis by controlling TKTL1 stability

Crucial role of the pentose phosphate pathway in malignant tumors

Interest in cancer metabolism has increased in recent years. The pentose phosphate pathway (PPP) is a major glucose catabolism pathway that directs glucose flux to its oxidative branch and leads to the production of a reduced form of nicotinamide adenine dinucleotide phosphate and nucleic acid. The PPP serves a vital role in regulating cancer cell growth and involves many enzymes. The aim of the present review was to describe the recent discoveries associated with the deregulatory mechanisms of the PPP and glycolysis in malignant tumors, particularly in hepatocellular carcinoma, breast and lung cancer.

Upregulation of valosin-containing protein (VCP) is associated with poor prognosis and promotes tumor progression of orbital B-cell lymphoma

Objective

This study aimed to investigate the relationship between VCP expression and the prognosis of orbital B-cell lymphoma patients and the influence of downregulation of VCP on the apoptosis and invasion abilities of lymphoma cells.

Methods

We recruited 66 orbital B-cell lymphoma patients. VCP expression in 66 samples of orbital B-cell lymphoma was determined by immunohistochemistry using monoclonal VCP antibodies. Based on VCP-expression levels detected by immunohistochemistry, we chose ten cases of orbital tumor paraffin tissue from the patients. Total RNA was extracted and differences in VCP gene-expression levels compared among patients using quantitative reverse-transcription (qRT) PCR. We used siRNA to knock down VCP in the lymphoma cell lines Raji and SUDHL4. qRT-PCR and Western blot were applied to detect VCP mRNA and protein expression, respectively. SUDHL48 assays were applied to investigate cell proliferation. Hoechst 33258 staining and flow-cytometry analysis were applied to investigate cell apoptosis. Transwell assays were applied to investigate invasive ability. Survival analysis was used to evaluate prognostic values.

Results

Expression levels of VCP were correlated with the stage, tumor grade, and recurrence rate of patients. VCP mRNA-expression levels were consistent with VCP-expression levels in orbital B-cell lymphoma tissue. Moreover, survival analysis revealed that lower VCP-expression levels were correlated with longer overall survival of orbital B-cell lymphoma patients. Down-regulation of VCP with siRNA did not inhibit cell proliferation. However, it dramatically increased apoptosis and suppressed the invasion of B-cell lymphoma cells.

Conclusion

VCP expression played an important role in the progression of orbital B-cell lymphoma. VCP could be a useful marker for predicting the prognosis of orbital B-cell lymphoma patients. VCP may be a potential therapeutic target for orbital B-cell lymphoma.

Transketolase like 1 (TKTL1) expression alterations in prostate cancer tumorigenesis

BACKGROUND

Prostate cancer (CaP) is the most common nonepidermal cancer in elderly males. Due to its heterogeneity and high variability in regards to clinical outcome and therapeutic response, urologists' handling of this disease remains a challenge. The objective of this study was to assess Transketolase like 1 (TKTL1) expression in benign prostatic tissue, peritumoral tissue and in CaP (in different stages of disease), and its correlation with clinicopathological findings, in order to detect if TKTL1 expression is associated with CaP tumorigenesis.

METHODS

In total, 100 tissue samples were included: (i) 22 benign specimens, (ii) 46 specimens with nonmetastatic CaP, and (iii) 32 specimens from patients with metastatic CaP. From the tissue microarray slides, we evaluated immunohistochemically the expression of the TKTL1 protein, using the H-score.

RESULTS

The TKTL1 protein expression pattern ranges from a low level in benign prostatic tissue (100 [57.5-105]), moderately low in peritumoral tissue (135.42 [100-195.16]), moderate expression in nonmetastatic CaP (200 [172.19-254.38]) to high in metastatic CaP (300 [222.50-300]). A significant rise of TKTL1 mean expression was seen throughout disease progression. A significant difference was also found in TKTL1 expression between peritumoral tissue and benign tissue.

CONCLUSION

The results obtained in this study suggest that pentose phosphate pathway and its key enzyme TKTL1 is altered throughout the CaP tumorigenesis, and this pathway merits further investigation.

Increased expression of hypoxia-inducible factor-1 alpha and its impact on transcriptional changes and prognosis in malignant tumours of the ocular adnexa

PURPOSE

To investigate the expression profile of the hypoxia-inducible transcription factor-1α (HIF-1α) and its downstream targets in malignancies of the ocular adnexa and to determine its relevance as a prognostic factor for clinical outcome.

METHODS

We included 49 subjects with malignant tumours (25 squamous cell carcinomas (SCC), 15 non-Hodgkin lymphomas, 9 melanomas) and 30 patients with benign tumours of the ocular adnexa (13 papillomas, 7 reactive lymphoid hyperplasias (RLHs) and 10 nevi) as controls. We quantified HIF-1α protein expression by immunohistochemistry and assessed the association between HIF-1α and clinical outcome via Kaplan-Meier analysis. Furthermore, we assessed the expression of HIF-1α downstream factors by transcriptional sequencing using the MACE (massive analysis of cDNA ends) technology.

RESULTS

SCCs revealed a strong HIF-1α expression in 61% of tumour cells in comparison with only 22% in papillomas (p < 0.0001). In contrast, malignant melanomas and lymphomas revealed a similar HIF-1α expression compared with nevi and RLHs. Transcriptional sequencing and Gene Ontology Cluster analysis demonstrated 37 hypoxia-associated factors, including HIF-1α, VEGF, SFRP1 and LOXL2 that are significantly increased in SCC and may contribute to tumour proliferation, angiogenesis, and metastasis. Association analysis between HIF-1α immunoreactivity and clinical outcome revealed a trend towards an unfavourable prognosis in malignant tumours with increased HIF-1α expression.

CONCLUSIONS

HIF-1α protein is increased in malignant tumours of the ocular adnexa, which is associated with an increase in multiple HIF-1α-downstream factors and a trend towards an unfavourable clinical outcome.

Ezh2 does not mediate retinal ganglion cell homeostasis or their susceptibility to injury

Epigenetic predisposition is thought to critically contribute to adult-onset disorders, such as retinal neurodegeneration. The histone methyltransferase, enhancer of zeste homolog 2 (Ezh2), is transiently expressed in the perinatal retina, particularly enriched in retinal ganglion cells (RGCs). We previously showed that embryonic deletion of Ezh2 from retinal progenitors led to progressive photoreceptor degeneration throughout life, demonstrating a role for embryonic predisposition of Ezh2-mediated repressive mark in maintaining the survival and function of photoreceptors in the adult. Enrichment of Ezh2 in RGCs leads to the question if Ezh2 also mediates gene expression and function in postnatal RGCs, and if its deficiency changes RGC susceptibility to cell death under injury or disease in the adult. To test this, we generated mice carrying targeted deletion of Ezh2 from RGC progenitors driven by Math5-Cre (mKO). mKO mice showed no detectable defect in RGC development, survival, or cell homeostasis as determined by physiological analysis, live imaging, histology, and immunohistochemistry. Moreover, RGCs of Ezh2 deficient mice revealed similar susceptibility against glaucomatous and acute optic nerve trauma-induced neurodegeneration compared to littermate floxed or wild-type control mice. In agreement with the above findings, analysis of RNA sequencing of RGCs purified from Ezh2 deficient mice revealed few gene changes that were related to RGC development, survival and function. These results, together with our previous report, support a cell lineage-specific mechanism of Ezh2-mediated gene repression, especially those critically involved in cellular function and homeostasis.

Differential Site-Based Expression of Pentose Phosphate Pathway-Related Proteins among Breast Cancer Metastases

Purpose. We aimed to investigate the expression of pentose phosphate pathway- (PPP-) related proteins in metastatic breast cancer and its relationship with clinicopathologic factors. Methods. Tissue samples from 126 metastatic breast cancers were included in a tissue microarray. Expression of PPP-related proteins [glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconolactonase (6PGL), 6-phosphogluconate dehydrogenase (6PGDH), and nuclear factor erythroid 2-related factor (NRF2)] was determined by immunohistochemistry. Results. G6PDH (p = 0.011) and cytoplasmic NRF2 (p = 0.001) showed the highest expression in brain metastases. Human epidermal growth factor receptor (HER-2) positivity was associated with G6PDH (p < 0.001) and cytoplasmic NRF2 (p = 0.015) positivity. A high Ki-67 labeling index (LI) was correlated with nuclear NRF2 positivity (p = 0.037), and HER-2-positive luminal B type was associated with G6PDH positivity (p = 0.001). On multivariate Cox analysis, independent risk factors of short overall survival were 6PGL positivity in bone metastasis (HR 4.180, 95% CI 1.160–15.06, p = 0.029) and low Ki-67 LI in lung metastasis (HR 11.853, 95% CI 1.841–76.30, p = 0.009). Conclusion. Differential expression of PPP-related proteins correlated with different prognoses and metastatic sites, with the highest expression in brain metastases, and could be a potential therapeutic target.

Modified Atkins diet in advanced malignancies - final results of a safety and feasibility trial within the Veterans Affairs Pittsburgh Healthcare System

Background

Dysfunctional mitochondrial processes limit malignant cells ability to use energy from fatty acids and ketones. Animal studies using ketogenic diets for cancer show encouraging results. We tested the diet’s safety and feasibility in cancer patients across a broad variety of solid tumors.

Methods

We recruited 17 advanced cancer patients who were not on chemotherapy. They consumed 20 to 40 g of carbohydrates daily with evaluations performed weekly until week 4, then every 4 weeks until 16 weeks. Quality of life questionnaires monitored for tolerability and compliance. Positron emission/computerized tomography was ordered at baseline, 4,8 and 16 weeks. Student t-testing evaluated differences between baseline and last visit scores for quality of life, weight, body mass index, and serum parameters. Correlations between weight loss and serum ketones, glucose, lipids and creatinine were done. Two-tailed unpaired t-testing of the mean weight loss compared responders against non-responders.

Results

Eleven out of seventeen enrolled patients were evaluable. Mean age was 65+/- 11.7 years, weight 203 +/- 4.98 lbs. (92 ± 2.3 kgs.) and previous treatment failures was 1.7, +/- 0.97. All lost significant weight with hematologic, biochemical and lipid tests remaining stable. Quality of life scores slightly improved. At 4,8 and 16 weeks, six (54.5 %), five (45.4 %) and four (36 %) patients were stable or improved. We observed no correlations between serum glucose, ketones or lipids. Clinical response did not correlate with ketosis or glycemia. Responders (stable disease or partial responders) lost statistically more weight than non-responders. Dietary compliance was difficult. Only three patients continued dieting past 16 weeks. Out of these, two patients developed brain metastases and were on steroids. They survived 80 and 116 weeks respectively. The third patient underwent residual tumor resection and has no disease at 131 weeks.

Conclusions

Modified Atkins diets are safe and feasible in advanced cancer. Quality of life was preserved. Patients who lost at least 10 % of their body weight responded the best. Steroid intake affected optimal ketone and glucose levels. Despite this, survival improved in some melanoma and lung cancer patients. Further studies are recommended.

Trial registration

Clinicaltrials.gov NCT01716468. Registered on September 18, 2012

Transketolase-like 1 ectopic expression is associated with DNA hypomethylation and induces the Warburg effect in melanoma cells

BACKGROUND

The metabolism of cancer cells is often reprogrammed by dysregulation of metabolic enzymes. Transketolase-like 1 (TKTL1) is a homodimeric transketolase linking the pentose-phosphate pathway with the glycolytic pathway. It is generally silenced at a transcriptional level in somatic tissues. However, in human cancers its expression is associated with the acquisition of a glycolytic phenotype (the Warburg effect) by cancer cells that contributes to the progression of malignant tumors. In melanoma, defective promoter methylation results in the expression of genes and their products that can affect the tumor cell's phenotype including the modification of immune and functional characteristics. The present study evaluates the role of TKTL1 as a mediator of disease progression in melanoma associated with a defective methylation phenotype.

METHODS

The expression of TKTL1 in metastatic melanoma tumors and cell lines was analysed by qRT-PCR and immunohistochemistry. The promoter methylation status of TKTL1 in melanoma cells was evaluated by quantitative methylation specific PCR. Using qRT-PCR, the effect of a DNA demethylating agent 5-aza-2'-deoxycytidine (5aza) on the expression of TKTL1 was examined. Biochemical and molecular analyses such as glucose consumption, lactate production, invasion, proliferation and cell cycle progression together with ectopic expression and siRNA mediated knockdown were used to investigate the role of TKTL1 in melanoma cells.

RESULTS

Expression of TKTL1 was highly restricted in normal adult tissues and was overexpressed in a subset of metastatic melanoma tumors and derived cell lines. The TKTL1 promoter was activated by hypomethylation and treatment with 5aza induced TKTL1 expression in melanoma cells. Augmented expression of TKTL1 in melanoma cells was associated with a glycolytic phenotype. Loss and gain of function studies revealed that TKTL1 contributed to enhanced invasion of melanoma cells.

CONCLUSIONS

Our data provide evidence for an important role of TKTL1 in aerobic glycolysis and tumor promotion in melanoma that may result from defective promoter methylation. This epigenetic change may enable the natural selection of tumor cells with a metabolic phenotype and thereby provide a potential therapeutic target for a subset of melanoma tumors with elevated TKTL1 expression.

Transketolase-like protein 1 expression predicts poor prognosis in colorectal cancer

BACKGROUND

Transketolase-like protein 1 (TKTL1) is an isoform of tranketolase, a key protein in a cancer cell's glucose metabolism that causes rapid cell growth and controls the non-oxidative part of the pentose phosphate pathway (PPP). Its overexpression occurs in several human cancer types. Our purpose was to study whether TKTL1 expression in colorectal cancer tissue associates with these patients' prognosis.

METHODS

We collected retrospectively patient data and tissue samples from 840 colorectal cancer patients treated at Helsinki University Hospital, then stained tumor tissue microarrays for TKTL1 by immunohistochemistry, and compared immunohistochemical tissue expression with clinico-pathological parameters and survival.

RESULTS

High expression of TKTL1 associated with high Dukes stage, non-mucinous adenocarcinoma, and left-sided disease. Patients with high TKTL1 expression had poorer prognosis than those with low expression, with a 5-year disease-specific survival of 55.7% vs. 62.7%.

CONCLUSION

We show that high TKTL1 in tumor tissue can lead to poor survival in colorectal cancer. TKTL1 thus can serve as a candidate marker for identifying patients at risk of recurrent disease.

The development of tumours under a ketogenic diet in association with the novel tumour marker TKTL1: A case series in general practice

Since the initial observations by Warburg in 1924, it has become clear in recent years that tumour cells require a high level of glucose to proliferate. Therefore, a ketogenic diet that provides the body with energy mainly through fat and proteins, but contains a reduced amount of carbohydrates, has become a dietary option for supporting tumour treatment and has exhibited promising results. In the present study, the first case series of such a treatment in general practice is presented, in which 78 patients with tumours were treated within a time window of 10 months. The patients were monitored regarding their levels of transketolase-like-1 (TKTL1), a novel tumour marker associated with aerobic glycolysis of tumour cells, and the patients' degree of adherence to a ketogenic diet. Tumour progression was documented according to oncologists' reports. Tumour status was correlated with TKTL1 expression (Kruskal-Wallis test, P<0.0001), indicating that more progressed and aggressive tumours may require a higher level of aerobic glycolysis. In palliative patients, a clear trend was observed in patients who adhered strictly to a ketogenic diet, with one patient experiencing a stagnation in tumour progression and others an improvement in their condition. The adoption of a ketogenic diet was also observed to affect the levels of TKTL1 in those patients. In conclusion, the results from the present case series in general practice suggest that it may be beneficial to advise tumour patients to adopt a ketogenic diet, and that those who adhere to it may have positive results from this type of diet. Thus, the use of a ketogenic diet as a complementary treatment to tumour therapy must be further studied in rigorously controlled trials.

TKTL1 expression in human malign and benign cell lines

Background

Overexpression of transketolase-like 1 protein TKTL1 in cancer cells has been reported to correlate with enhanced glycolysis and lactic acid production. Furthermore, enhanced TKTL1 expression was put into context with resistance to chemotherapy and ionizing radiation. Here, a panel of human malign and benign cells, which cover a broad range of chemotherapy and radiation resistance as well as reliance on glucose metabolism, was analyzed in vitro for TKTL1 expression.

Methods

17 malign and three benign cell lines were characterized according to their expression of TKTL1 on the protein level with three commercially available anti-TKTL1 antibodies utilizing immunohistochemistry and Western blot, as well as on mRNA level with three published primer pairs for RT-qPCR. Furthermore, sensitivities to paclitaxel, cisplatin and ionizing radiation were assessed in cell survival assays. Glucose consumption and lactate production were quantified as surrogates for the “Warburg effect”.

Results

Considerable amounts of tktl1 mRNA and TKTL1 protein were detected only upon stable transfection of the human embryonic kidney cell line HEK293 with an expression plasmid for human TKTL1. Beyond that, weak expression of endogenous tktl1 mRNA was measured in the cell lines JAR and U251. Western blot analysis of JAR and U251 cells did not detect TKTL1 at the expected size of 65 kDa with all three antibodies specific for TKTL1 protein and immunohistochemical staining was observed with antibody JFC12T10 only. All other cell lines tested here revealed expression of tktl1 mRNA below detection limits and were negative for TKTL1 protein. However, in all cell lines including TKTL1-negative HEK293-control cells, antibody JFC12T10 detected multiple proteins with different molecular weights. Importantly, JAR and U251 did neither demonstrate an outstanding production of lactic acid nor increased resistance against chemotherapeutics or to ionizing radiation, respectively.

Conclusion

Using RT-qPCR and three different antibodies we observed only exceptional occurrence of TKTL1 in a panel of malignant human cell lines in vitro. The presence of TKTL1 was unrelated to either the rate of glucose consumption/lactic acid production or resistance against chemo- and radiotherapy.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-15-2) contains supplementary material, which is available to authorized users.

TKTL1 expression and its downregulation is implicated in cell proliferation inhibition and cell cycle arrest in esophageal squamous cell carcinoma

It is well known that tumor cells mainly depend on the nonoxidative pathway of the pentose phosphate pathway (PPP), and transketolase-like 1 (TKTL1), a kind of crucial metabolism enzyme, participates in the regulation of PPP; notably, overwhelming evidence has demonstrated that TKTL1 plays pivotal roles in the development and progression of multiple tumors. However, there were no reports about the role of TKTL1 in esophageal squamous cell carcinoma (ESCC). Here, we investigated TKTL1 expression and preliminarily elucidated its underlying biological functions in ESCC. We found that TKTL1 exhibited the high expression in ESCC tissues and cells, and the survival rate of patients with negative TKTL1 expression was significantly higher than that of patients with positive TKTL1 staining (P < 0.05). Additionally, significant correlations of TKTL1 expression with histologic grade, clinical stage, and lymph node metastasis were found (P < 0.05). Subsequently, TKTL1 small interfering RNA (siRNA) significantly reduced TKTL1 messenger RNA (mRNA), and protein levels companied with the marked reduce of total transketolase activity but did not affect TKT and TKTL1 mRNA level. More importantly, TKTL1 siRNA obviously induced cell cycle arrest in G0/G1 phase and suppressed cell proliferation in vitro and in vivo coupled with the reduced cyclin D1 and cdk4 levels as well as decrease of Ki-67 proliferation index in EC1 cells. Taken altogether, our results suggest that TKTL1 as a key prognostic factor may be a novel target for therapy of the patients with ESCC.

A biomarker based detection and characterization of carcinomas exploiting two fundamental biophysical mechanisms in mammalian cells

Background

Biomarkers allowing the characterization of malignancy and therapy response of oral squamous cell carcinomas (OSCC) or other types of carcinomas are still outstanding. The biochemical suicide molecule endonuclease DNaseX (DNaseI-like 1) has been used to identify the Apo10 protein epitope that marks tumor cells with abnormal apoptosis and proliferation. The transketolase-like protein 1 (TKTL1) represents the enzymatic basis for an anaerobic glucose metabolism even in the presence of oxygen (aerobic glycolysis/Warburg effect), which is concomitant with a more malignant phenotype due to invasive growth/metastasis and resistance to radical and apoptosis inducing therapies.

Methods

Expression of Apo10 and TKTL1 was analysed retrospectively in OSCC specimen (n = 161) by immunohistochemistry. Both markers represent independent markers for poor survival. Furthermore Apo10 and TKTL1 have been used prospectively for epitope detection in monocytes (EDIM)-blood test in patients with OSCC (n = 50), breast cancer (n = 48), prostate cancer (n = 115), and blood donors/controls (n = 74).

Results

Positive Apo10 and TKTL1 expression were associated with recurrence of the tumor. Multivariate analysis demonstrated Apo10 and TKTL1 expression as an independent prognostic factor for reduced tumor-specific survival. Apo10+/TKTL1+ subgroup showed the worst disease-free survival rate in OSCC.

EDIM-Apo10 and EDIM-TKTL1 blood tests allowed a sensitive and specific detection of patients with OSCC, breast cancer and prostate cancer before surgery and in after care. A combined score of Apo10+/TKTL1+ led to a sensitivity of 95.8% and a specificity of 97.3% for the detection of carcinomas independent of the tumor entity.

Conclusions

The combined detection of two independent fundamental biophysical processes by the two biomarkers Apo10 and TKTL1 allows a sensitive and specific detection of neoplasia in a noninvasive and cost-effective way. Further prospective trials are warranted to validate this new concept for the diagnosis of neoplasia and tumor recurrence.

EDIM-TKTL1 blood test: a noninvasive method to detect upregulated glucose metabolism in patients with malignancies

AIM

To determine whether the TKTL1 protein epitope detection in monocytes (EDIM) test allows detection of upregulated glucose metabolism in malignancies.

MATERIALS & METHODS

The EDIM-TKTL1 blood test was conducted in 240 patients with 17 different confirmed or suspected malignancies. Test scores were compared with (18)F-fluoro-2-deoxy-D-glucose (FDG)-PET/computed tomography (CT) results.

RESULTS

EDIM-TKTL1 score and FDG-PET results showed a concordance of 90% with a sensitivity of 94% and specificity of 81%. Including CT data, all values were enhanced. A subgroup analysis of non-small-cell lung cancer patients showed a significant correlation between the EDIM-TKTL1 score and the primary tumor size determined by FDG-PET/CT.

CONCLUSION

EDIM-TKTL1 blood test revealed good concordance with FDG-PET/CT results in patients with malignancies demonstrating its efficacy to detect upregulation of glucose metabolism in primary tumors or metastases.