Effect of Akt activation and experimental pharmacological inhibition on responses to neoadjuvant chemoradiotherapy in rectal cancer

BACKGROUND

Neoadjuvant chemoradiotherapy (CRT) is one of the preferred initial treatment strategies for locally advanced rectal cancer. Responses are variable, and most patients still require surgery. The aim of this study was to identify molecular mechanisms determining poor response to CRT.

METHODS

Global gene expression and pathway enrichment were assessed in pretreatment biopsies from patients with non-metastatic cT2-4 N0-2 rectal cancer within 7 cm of the anal verge. Downstream Akt activation was assessed in an independent set of pretreatment biopsies and in colorectal cancer cell lines using immunohistochemistry and western blot respectively. The radiosensitizing effects of the Akt inhibitor MK2206 were assessed using clonogenic assays and xenografts in immunodeficient mice.

RESULTS

A total of 350 differentially expressed genes were identified, of which 123 were upregulated and 199 downregulated in tumours from poor responders. Mitochondrial oxidative phosphorylation (P < 0·001) and phosphatidylinositol signalling pathways (P < 0·050) were identified as significantly enriched pathways among the set of differentially expressed genes. Deregulation of both pathways is known to result in Akt activation, and high immunoexpression of phosphorylated Akt S473 was observed among patients with a poor histological response (tumour regression grade 0-2) to CRT (75 per cent versus 48 per cent in those with a good or complete response; P = 0·016). Akt activation was also confirmed in the radioresistant cell line SW480, and a 50 per cent improvement in sensitivity to CRT was observed in vitro and in vivo when SW480 cells were exposed to the Akt inhibitor MK2206 in combination with radiation and 5-fluorouracil.

CONCLUSION

Akt activation is a key event in the response to CRT. Pharmacological inhibition of Akt activation may enhance the effects of CRT. Surgical relevance Organ preservation is an attractive alternative in rectal cancer management following neoadjuvant chemoradiotherapy (CRT) to avoid the morbidity of radical surgery. Molecular steps associated with tumour response to CRT may provide a useful tool for the identification of patients who are candidates for no immediate surgery. In this study, tumours resistant to CRT were more likely to have activation of specific genetic pathways that result in phosphorylated Akt (pAkt) activation. Pretreatment biopsy tissues with high immunoexpression of pAkt were more likely to exhibit a poor histological response to CRT. In addition, the introduction of a pAkt inhibitor to cancer cell lines in vitro and in vivo led to a significant improvement in sensitivity to CRT. Identification of pAkt-activated tumours may thus allow the identification of poor responders to CRT. In addition, the concomitant use of pAkt inhibitors to increase sensitivity to CRT in patients with rectal cancer may constitute an interesting strategy for increasing the chance of a complete response to treatment and organ preservation.

A comparative study between two central veins for the introduction of totally implantable venous access devices in 1201 cancer patients

INTRODUCTION AND AIMS

The Subclavian vein has been traditionally the vein of choice for central venous catheterization by general surgeons. Alternative settings for the introduction of totally implantable venous access devices (TIVAD) and the search for lower rates of morbidity led to the choice of other central veins. This study compares two different venous accesses, the subclavian (SC) versus the internal jugular (IJ), in terms of early and late morbidity.

PATIENTS AND METHODS

This is a prospective, non-randomized, observational, uni-institutional (tertiary cancer centre) study. From March 2003 to March 2006, 1231 TIVADs were placed (1201 patients), in an ambulatory operating room, under vital signs and EKG monitoring, using local anaesthesia and without perioperative radiological control.

RESULTS

Of the 1231 TIVAD, 617 were inserted via the SC and 614 via the IJ vein. The two groups (SC vs. IJ) were comparable as to general patient characteristics. Immediate complications were more frequent in the SC than in the IJ approach (respectively, 5.0% vs. 1.5%; p<0.001); Catheter malposition occurred in 2.3% when using the SC vein and in 0.2% for the IJ (p=0.001). Long term morbidity was also more frequent in the SC than in the IJ group (respectively, 15.8%, 87/551, vs. 7.6%, 39/512; p<0.001). Venous thrombosis developed in 2.0% of patients with an SC TIVAD as compared to 0.6% with an IJ TIVAD (p=0.044). Catheter malfunction was significantly dependent on the vein used: SC - 9.4% vs. IJ - 4.3% (p=0.001).

CONCLUSIONS

Our results support the preferential use of the Internal Jugular vein for the insertion of TIVAD.

Antibacterial proteins in rainbow trout, Oncorhynchus mykiss

Antibacterial proteins are an important part of the innate immune system for all animals. They have been extensively studied in mammals, amphibians and invertebrates, but have received only scant attention in fish. Their expression and processing, however, provide a way of monitoring defence vigour during development or with seasonal changes in physiology. The aim of the present work was to identify and characterise antibacterial proteins in rainbow trout. In vitro analyses of extracts of the peripheral blood leucocytes, head kidney leucocytes and mucus from adult unstimulated (non-immune) fish showed marked antibacterial activity against Gram positive bacteria. Fractionation by ion exchange chromatography and RP-HPLC of head kidney extracts showed the presence of two forms of lysozyme but no constitutively expressed antimicrobial proteins of < 10 kDa. By contrast, chromatographic analyses of mucus revealed at least four antibacterial proteins. Two are conventional lysozymes, a third is an unusual lysozyme-like protein with a low isoelectric point, and the fourth is a highly hydrophobic, cationic peptide of c. 3 kDa.

Lunar phase and psychiatric illness in goa

There has been considerable research on the influence of the lunar cycle on mental illness with conflicting findings. The objective of this study was to determine the relationship between full moon (FM), new moon (NM), and other moon (OM) days and the frequency of specific psychiatric disorders in patients seen at a tertiary psychiatric hospital in Goa and to examine relationships with eclipses. Analysis of all new patients in two calendar years (1997 & 1993) was carried out. Diagnoses of interest were : Non affective psychoses; depression; and mania. The numbers of new patients seen at the OPD of the Institute of Psychiatry & Human Behaviour, Goa, with these diagnoses were compared between FM, NM and OM days. Numbers of patients with these diagnoses on eclipse days (lunar/solar) were also examined. A significant trend was observed for greater numbers of patients with non-affective psychoses on FM days, but no pattern was observed for mania or depression. The excess of non-affective psychoses was more marked on days of a visible lunar eclipse. A relationship between FM and non-affective psychoses has been demonstrated. Its implications for further research and the potential mechanism to explain these findings are discussed.

[Foreign-body aspiration in adults]

Proximal airway obstruction and acute life-threatening asphyxia is the most important complication of foreign body aspiration. Small foreign bodies that transverse the larynx may be initially asymptomatic appearing serious respiratory disturbances only later. Three patients with different clinical evolutions are reported and the diagnostic and therapeutic approaches, discussed.