Kinetics of glycogen levels in asynchronous and synchronous cultures of a human colon carcinoma cell line, HT 29

Clinical Features, Survival and Prognostic Factors of Glycogen-Rich Clear Cell Carcinoma (GRCC) of the Breast in the U.S. Population

The World Health Organization (WHO) defines glycogen-rich clear cell carcinoma (GRCC) of the breast as a carcinoma with glycogen accumulation in more than 90% of its tumor cells. Due to the rarity of this disease, its reported survival and clinical associations have been inconsistent due to reliance on case reports and limited case series. As a result, the prognostic implication of this cancer subtype remains unclear. Using the U.S. Surveillance, Epidemiology, and End Results (SEER) program database, we compared the incidence, demographics and prognostic factors of 155 cases of GRCC of the breast to 1,251,584 cases of other (non-GRCC) breast carcinomas. We demonstrate that GRCC is more likely to be identified as high grade, advanced stage, and more likely to have triple negative receptor status. GRCC cases display a poorer prognosis than non-GRCC carcinomas of the breast irrespective of age, AJCC staging, tumor grade, joint hormone receptor/human epidermal growth factor receptor 2 (HER2) status, and treatment. Similar to non-GRCC carcinomas, older age and higher American Joint Committee on Cancer (AJCC)/TNM staging were associated with poorer prognosis for GRCC, while treatment with surgery and radiation were associated with improved survival. Radiation, specifically in the setting of breast-conserving surgery, further improved survival compared to surgery alone. Our study highlights the poorer prognosis associated with glycogen accumulation in breast cancers and hence stresses the importance of identifying this more aggressive tumor type.

Glycogen metabolism has a key role in the cancer microenvironment and provides new targets for cancer therapy

Metabolic reprogramming is a hallmark of cancer cells and contributes to their adaption within the tumour microenvironment and resistance to anticancer therapies. Recently, glycogen metabolism has become a recognised feature of cancer cells since it is upregulated in many tumour types, suggesting that it is an important aspect of cancer cell pathophysiology. Here, we provide an overview of glycogen metabolism and its regulation, with a focus on its role in metabolic reprogramming of cancer cells under stress conditions such as hypoxia, glucose deprivation and anticancer treatment. The various methods to detect glycogen in tumours in vivo as well as pharmacological modulators of glycogen metabolism are also reviewed. Finally, we discuss the therapeutic value of targeting glycogen metabolism as a strategy for combinational approaches in cancer treatment.

Effect of VIP on the glycogen metabolism of human colon adenocarcinoma cells studied by 13C nuclear magnetic resonance spectroscopy

Metabolic pathways of glucose utilization have been investigated in a human colon adenocarcinoma cell line (HT29) using carbon-13 Nuclear Magnetic Resonance spectroscopy. HT29 cells were adapted to grow on a polystyrene beaded microcarrier and were perfused when attached to the beads in a specially designed NMR cell. Abnormalities in carbohydrate metabolism already observed in several cancer cells were studied in HT29 cells fed with (1-13C)-enriched glucose. The cells were first perfused with a glucose-free medium for 2 h in order to deplete the intracellular store of glycogen, and they were subsequently perfused with a medium containing enriched glucose at an initial concentration of 5.5 mM. Sequential 13C-NMR spectra, recorded at 100.5 MHz (5 min accumulation), show that HT29 cells were able to utilize glucose through the glycolytic pathway while storing glucose as glycogen (glucose was utilized at a rate of 3.9 mumol/mg protein/hr). The glycolytic activity determined by the amount of lactic acid produced was 4.6 microns/mg protein/hr, corresponding to the formation of 1.2 lactic acid per glucose molecule. Glycogen accumulation corresponded to 16 micrograms/mg of protein. Treatment of HT29 with 10 nM vasoactive intestinal peptide (VIP) induced a transient decrease in the level of labelled glycogen to 50% of the initial value. Control level was recovered 12 min after VIP loading.