Predictors of weight loss during conformal radiotherapy for head and neck cancers - how important are planning target volumes?

AIMS

Nutritional compromise is common during high dose radiotherapy (RT) or chemoradiotherapy (CRT) for head and neck cancers. We aimed to identify the factors that determine nutritional outcome for head and neck cancer patients during radiotherapy.

METHODS

Data from 103 patients with head and neck cancer treated with highly conformal radiotherapy to doses of 60 Gy or more in 30-33 fractions in the adjuvant or definitive setting was analyzed. All patients received complex 3D conformal radiotherapy (3DCRT) or intensity modulated radiotherapy (IMRT). Patients received regular nutritional counseling and need-based interventions. Their weight was recorded at the beginning and end of radiotherapy. Using univariate and multivariate models we tested possible predictors of weight loss of >5% and NG tube requirement.

RESULTS

The mean weight loss was 3.8%. The incidence of weight loss >5% was 37.9% and NG tube placement was 24.3%. The factors significantly associated with >5% weight loss in the univariate analysis were tumor site (oro-hypopharyngeal vs. others), definitive vs. adjuvant RT; prescription dose of >60 Gy vs. 60 Gy; CRT vs. RT alone; prescription dose planning target volume (PTV) volume >235 cc and total PTV volume >615 cc. Age, sex, T stage, N stage and modality (3DCRT/IMRT) were not significant. In multivariate analysis, the total PTV volume, prescription dose PTV volume and use of chemotherapy were significant after controlling for other factors. Patients could be risk stratified based on the use of CRT and large PTV volumes. Patients with none, one or both factors had a likelihood of >5% weight loss of 0%, 30.3%, and 56.9% (p < 0.001) and likelihood of NG tube placement of 5.3%, 15.2% and 37.3% (p = 0.007).

CONCLUSIONS

It is possible to predict weight loss and NG tube requirements from disease and treatment related factors. PTV volumes are important predictors of nutritional compromise. Risk stratification may enable more focused counseling and identification of patients who require preventive interventions.

Abstract 5248: Tunneling nanotubes connect melanoma cells and mediate transfer of mitochondria and GRP78

Background: Recently, exciting reports have outlined the existence and function of very thin, membranous conduits between cells that span significant distances, termed tunneling nanotubes (TnTs). TnTs have been observed in neoplastic and normal cells, and may transport soluble proteins, such as P-glycoprotein (MDR1), lipids, and whole organelles, including mitochondria and Golgi vesicles, between cells. Furthermore, TnTs mediate intercellular Ca2+ signals and transmit electrical potentials. However, their functional characterization remains incomplete.

Objectives: Our objective is to describe TnT formation and function in melanoma cell lines and primary tumor samples.

Methods: We describe the presence and composition of TnTs between cells in the melanoma cell lines SK-Mel-31, DM440, DM443, DM738, and DM598 in vitro with a combination of brightfield and fluorescent microscopy techniques. TnT formation is assessed in response to hypoxia, glucose stress, and low pH. Bulk intercellular transport of mitochondria is quantified via flow cytometry using MitotrackerTM dyes, and GFP-GRP78 fusion proteins are used for studies of protein transport. Additional flow cytometric studies include JC-1 staining to measure mitochondrial membrane potential, annexin V binding to measure apoptosis, and 7-AAD exclusion for live/dead staining. Fluorescent ATP assays are used to measure general metabolic capacity, and confocal microscopy of primary melanoma specimens is performed using melanosome-specific (P100) and dsDNA (H33342) stains.

Results All tested cell lines formed TnT-like structures with variable F-actin and tubulin composition. Mitochondria and Golgi vesicles were visible within live and fixed TnTs, which were formed constitutively and were further induced by hypoxia, glucose stress, and low pH. In an actin-dependent process, cells rapidly transferred labeled mitochondria, achieving homogeneity within 24 h as measured by flow cytometry. Transfer of healthy mitochondria from unstressed cells significantly mitigated the acute toxicity of chemotherapeutically damaged cells. GRP78 was also rapidly transferred between cells, and the transfer of GRP78 from healthy donor cells rescued cells damaged by chemotherapeutics as measured by a decreased apoptotic rate.

Conclusions: Here, we report for the first time, the characterization of TnTs between melanoma cells. Moreover, melanoma cells acquired primary and secondary chemotherapeutic resistance to alkylating agents melphalan and temozolomide and the BRAFV600E inhibitor, vemurafenib, via bulk intercellular transfer of functional mitochondria and the ER stress protein, GRP78. TnT inhibitors would represent a novel class of chemotherapeutics with implications for invasion, metastasis, and chemotherapeutic resistance.

Citation Format: Gustaaf G. de Ridder, Rupa Ray, Salvatore V. Pizzo. Tunneling nanotubes connect melanoma cells and mediate transfer of mitochondria and GRP78. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5248. doi:10.1158/1538-7445.AM2013-5248

Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.

Abstract 1247: Development of GRP78 scFv-Subtilase fusion proteins for sensitization of melanoma to chemotherapeutics

GRP78 is an important molecular chaperone in the endoplasmic reticulum (ER). However, GRP78 is aberrantly expressed on the surface of melanoma cells. Our objective is to characterize cell-surface GRP78 in melanoma and determine whether immunoconjugates against GRP78 are a viable treatment strategy. We have demonstrated that cleavage of ER GRP78 by Subtilase (SubAB), a GRP78-specific protease, sensitizes melanoma cell lines of different genotypes to melphalan, vemurafenib, and temozolomide. Our data indicate that SubAB cleavage of GRP78 sensitizes melanoma cells to melphalan and vemurafenib. We then coupled the catalytic domain of SubAB, SubA, to GRP78-single chain variable fragments derived from anti-GRP78 mouse monoclonal antibodies. We have previously published that these antibodies target GRP78+ mouse melanomas in a syngeneic mouse melanoma model. These GRP78 scFv-SubA fusion proteins are internalized by cell-surface GRP78 and the SubA moiety cleaves ER GRP78 inside the cell, leading to tumor cell sensitization to chemotherapeutics, and in some instances, tumor cell death. To determine the mechanism by which ER GRP78 cleavage sensitizes melanoma cells to chemotherapeutics, the NH2-terminal 28 kDa and COOH-terminal 50 kDa SubA cleavage products were overexpressed in melanoma cells, and pull-down experiments were performed to identify binding partners. Microarray analyses were also performed on chemotherapy-treated and GRP78 scFv-SubA fusion protein-treated melanoma cells to obtain a broad view of cellular events that occurred subsequent to ER GRP78 cleavage by SubAB or GRP78 scFv-SubA fusion proteins. These fusion proteins will then be tested in mouse melanoma models to determine whether they sensitize cancer cells to chemotherapeutics in vivo. These results of these studies may lead to the development of novel melanoma therapeutics.

Citation Format: Rupa Ray, Gustaaf de Ridder, Salvatore V. Pizzo. Development of GRP78 scFv-Subtilase fusion proteins for sensitization of melanoma to chemotherapeutics. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1247. doi:10.1158/1538-7445.AM2013-1247

Implication of organic matter on arsenic and antimony sequestration in sediment: evidence from Sundarban mangrove forest, India

This study reports the measurement of stability constants for the interaction of As (V and III) and Sb (V and III) with humic substances extracted from aquatic sediments of the Sundarban mangrove forest ecosystem. It was observed that As and Sb formed a slightly more stable association with fulvic acid (FA) than with its humic acid (HA) counterpart. Quenching of fluorescence at increasing As (III and V) or Sb (III and V): FA or HA ratios was obtained that ideally correspond to a 1:1 complexation model. Quite strong complexation of As and Sb by FA and HA occurs at neutral pH, indicating that HA and FA probably markedly affect the mobility of As and Sb in the mangrove environment.

The voltage-dependent anion channel (VDAC) binds tissue-type plasminogen activator and promotes activation of plasminogen on the cell surface

The voltage-dependent anion channel (VDAC), a major pore-forming protein in the outer membrane of mitochondria, is also found in the plasma membrane of a large number of cells where in addition to its role in regulating cellular ATP release and volume control it is important for maintaining redox homeostasis. Cell surface VDAC is a receptor for plasminogen kringle 5, which promotes partial closure of the channel. In this study, we demonstrate that VDAC binds tissue-type plasminogen activator (t-PA) on human neuroblastoma SK-N-SH cells. Binding of t-PA to VDAC induced a decrease in K(m) and an increase in the V(max) for activation of its substrate, plasminogen (Pg). This resulted in accelerated Pg activation when VDAC, t-PA, and Pg were bound together. VDAC is also a substrate for plasmin; hence, it mimics fibrin activity. Binding of t-PA to VDAC occurs between a t-PA fibronectin type I finger domain located between amino acids Ile(5) and Asn(37) and a VDAC region including amino acids (20)GYGFG(24). These VDAC residues correspond to a GXXXG repeat motif commonly found in amyloid β peptides that is necessary for aggregation when these peptides form fibrillar deposits on the cell surface. Furthermore, we also show that Pg kringle 5 is a substrate for the NADH-dependent reductase activity of VDAC. This ternary complex is an efficient proteolytic complex that may facilitate removal of amyloid β peptide deposits from the normal brain and cell debris from injured brain tissue.

Wood chemistry and density: an analog for response to the change of carbon sequestration in mangroves

This study aimed to resolve the variations of physical and chemical properties of wood records measured in different mangroves with their annual carbon sequestration. The methods of investigation used were to examine growth rate by monitoring breast height diameter, wood chemistry and density, FTIR spectroscopy and thermogravimetry. Carbon sequestration rate showing an increase with density varied between 0.088 and 0.171 μg C kg(-1) AGB s(-1), and Avicennia marina showed the maximum value and Bruguiera gymnorrhiza, the minimum. The changes in FTIR bands at 4000-2500 cm(-1) and 1700-800 cm(-1) were correlated to the variations in cellulose in mangrove woods and lignin to cellulose ratio ranged between 0.21 and 1.75. Thermal analyses of mangrove wood suggested that the fuel value index (985-3922) exhibited an increase with the decrease in maximum decomposition temperature and density. The seasonal variation of temperature and CO2 were likely to affect chemical properties through changes in wood density.

The Escherichia coli subtilase cytotoxin A subunit specifically cleaves cell-surface GRP78 protein and abolishes COOH-terminal-dependent signaling

GRP78, a molecular chaperone with critical endoplasmic reticulum functions, is aberrantly expressed on the surface of cancer cells, including prostate and melanoma. Here it functions as a pro-proliferative and anti-apoptotic signaling receptor via NH(2)-terminal domain ligation. Auto-antibodies to this domain may appear in cancer patient serum where they are a poor prognostic indicator. Conversely, GRP78 COOH-terminal domain ligation is pro-apoptotic and anti-proliferative. There is no method to disrupt cell-surface GRP78 without compromising the total GRP78 pool, making it difficult to study cell-surface GRP78 function. We studied six cell lines representing three cancer types. One cell line per group expresses high levels of cell-surface GRP78, and the other expresses low levels (human hepatoma: Hep3B and HepG2; human prostate cancer: PC3 and 1-LN; murine melanoma: B16F0 and B16F1). We investigated the effect of Escherichia coli subtilase cytoxin catalytic subunit (SubA) on GRP78. We report that SubA specifically cleaves cell-surface GRP78 on HepG2, 1-LN, and B16F1 cells without affecting intracellular GRP78. B16F0 cells (GRP78(low)) have lower amounts of cleaved cell-surface GRP78. SubA has no effect on Hep3B and PC3 cells. The predicted 28-kDa GRP78 COOH-terminal fragment is released into the culture medium by SubA treatment, and COOH-terminal domain signal transduction is abrogated, whereas pro-proliferative signaling mediated through NH(2)-terminal domain ligation is unaffected. These experiments clarify cell-surface GRP78 topology and demonstrate that the COOH-terminal domain is necessary for pro-apoptotic signal transduction occurring upon COOH-terminal antibody ligation. SubA is a powerful tool to specifically probe the functions of cell-surface GRP78.

Small Colony variants of Staphylococcus aureus isolated from a patient with infective endocarditis: a case report and review of the literature

Staphylococcus aureus produces a particular morphological variant called small colony variant (SCV) which is responsible for persistent subclinical infections in predisposed individuals and is usually resistant to aminoglycosides and cell wall active antibiotics. Infections by SCV of S. aureus are an upcoming problem due to difficulty in laboratory diagnosis and resistance to antimicrobial chemotherapy. We here report a case of infective endocarditis caused by SCV of Staphylococcus aureus in a pediatric patient.

Verruciform xanthoma of the penis in a young male masquerading as squamous cell carcinoma: case report

Verruciform xanthoma (VX) is a relatively rare benign lesion of unknown etiology with a predilection for oral mucosa. Penis is an uncommon location and to date only 17 cases of VX of penis have been reported. The lesion assumes importance as it can be easily mistaken for verrucous carcinoma or squamous cell carcinoma. We present herein a case of penile VX in a 25-year-old man who was referred to our institute with a histopathologic diagnosis of squamous cell carcinoma reported elsewhere. On microscopy the lesion demonstrated florid verruciform hyperplasia of the epidermis with hyperkeratosis, parakeratosis and acanthosis. There was a dense infiltrate of foam cells in the papillary dermis (a hallmark of VX), which were positive for CD68 and negative for S-100 protein. We present this case to highlight the significance of recognizing VX in extra oral location. An awareness of this entity is crucial to prevent misdiagnosis and halt inappropriate therapeutic intervention.

Telmisartan, a dual ARB/partial PPAR-γ agonist, protects myocardium from ischaemic reperfusion injury in experimental diabetes

AIM

Apart from its angiotensin receptor blocker (ARB) activity, telmisartan is also a partial agonist of peroxisome proliferator-activated receptor gamma (PPAR-γ). Therefore, we assessed whether telmisartan treatment attenuates myocardial ischaemia/reperfusion (I/R) injury in diabetic rats through PPAR-γ pathway.

METHODS

Diabetic rats were randomized to receive vehicle (sham and I/R), telmisartan (10 mg/kg/day, orally), PPAR-γ antagonist GW9662 (1 mg/kg/day, intraperitoneally) or both for 14 days. On 15th day, excluding sham group, left anterior descending coronary artery occlusion was performed for 45 min followed by 1 h of reperfusion. Haemodynamic, biochemical, histopathological, ultrastructural, immunohistochemical (Bax and Bcl-2 protein), TUNEL positivity, infarct size and western blot studies were performed.

RESULTS

Telmisartan treatment significantly improved cardiac function by normalizing mean arterial pressure, left ventricular pressure (±LVdP/dt(max) , a marker of myocardial contraction and relaxation), by decreasing left ventricular end-diastolic pressure (a marker of preload, 3.7 ± 0.41 vs. 7.3 ± 0.89, p < 0.001) and percent infarct area (37.52 ± 5.83 vs. 46.27 ± 3.20, p < 0.01) as compared to diabetic I/R group. Interestingly, GW9662 worsens the I/R injury (percent infarct area, 54.38 ± 6.48 vs. 46.27 ± 3.20, p < 0.01), whereas telmisartan with GW9662 (percent infarct area, 41.16 ± 8.23 vs. 46.27 ± 3.20, p < 0.05) showed lesser significant results as compared to telmisartan alone. Additionally, telmisartan significantly ameliorates activities of endogenous antioxidants, creatine kinase-MB isoenzyme, lactate dehydrogenase and prevented the increase of tumour necrosis factor-alpha and malondialdehyde in myocardium. Furthermore, telmisartan also decreased Bax expression (4.45 ± 1.24% vs. 10.25 ± 0.96%, p < 0.01), number of TUNEL-positive cells (6.2 ± 0.98% vs. 13.0 ± 1.6, p < 0.01), inflammation, myonecrosis and increased Bcl-2 expression (5.45 ± 0.15% vs. 1.24 ± 0.3%, p < 0.01). On the other hand, GW9662 treatment alone increased the Bax expression, TUNEL positivity and decreased Bcl-2 expression. Telmisartan protective effects were partially attenuated by a co-administration with GW9662. Western blot analysis showed that telmisartan treatment enhanced PPAR-γ expression, whereas GW9662 decreased it in myocardium.

CONCLUSIONS

In addition to the class effect of ARBs, telmisartan has a beneficial effect in I/R injury in diabetic rats in part because of activation of PPAR-γ.

Modulation of the unfolded protein response by GRP78 in prostate cancer

The unfolded protein response (UPR) is an adaptive survival mechanism through which cells can weather the stress of misfolded protein accumulation induced by a wide variety of pathophysiologic and pharmacologic insults. The ER chaperone GRP78 is a central modulator of the UPR both through its protein-binding capacity and its direct regulation of the UPR signaling molecules IRE1α, PERK, and ATF6. Recent reports have revealed the presence of GRP78 on the surface of cancer cells. Biological roles for cell-surface GRP78 include competing NH(2)-domain and COOH-domain agonist receptor activities that induce opposite effects on proliferation and apoptosis. Modulation of the UPR impacts both of these processes directly and indirectly. Here, we outline methods that we use to investigate UPR modulation via direct ligation of cell-surface GRP78. Specifically, we review methods of cell culture, cell-signaling analysis with emphasis on UPR components, and ultimately, the impact that these have on cell proliferation, survival, and apoptosis.

Level of heavy metals in some edible marine fishes of mangrove dominated tropical estuarine areas of Hooghly River, north east coast of Bay of Bengal, India

The muscles of some important marine fishes collected in and around Hooghly estuarine coastal areas were analyzed for the heavy metals Cu, Zn, Ni, Cd, Cr and Pb. The concentration range of Cu (16.22-47.97 ppm), Pb (12.40-19.96 ppm) and Zn (12.13-44.74 ppm) were recorded comparatively higher and were similar to that found in contaminated areas. On the other hand the ranges of Ni (2.20-3.69 ppm), Cr (0-3.89 ppm) and Cd (0.62-1.20 ppm) were almost equal to those carried out over a wide range of geographical areas. The degree of bioaccumulations was metal-specific as well as species-specific in nature. The toxic groups of metals (Pb and Cd) showed higher variability than the essential metals (Cu, Zn and Ni). The calculated intake value of metals (week⁻¹ kg⁻¹ body wt) varied from 14.88 to 27.60 of Pb, 0.87 to 1.68 of Cd, 0.0 to 5.45 of Cr, 22.70 to 137.16 of Cu, 3.08 to 5.17 of Ni and 16.98 to 62.60 of Zn through human consumption of these fishes and were compared with those of standard Provisional Tolerable Weekly Intake value (PTWI) per kg body weight as stipulated by WHO. The PTWI(Cal) values of Pb in some of the fishes recorded marginally excess values and may indicate a health risk through consumption of successive 7 days in a week.