Novel chemotherapeutic agents in colorectal cancer

HMGB1-mediated autophagy modulates sensitivity of colorectal cancer cells to oxaliplatin via MEK/ERK signaling pathway

In the present study, we examined the mechanisms of oxaliplatin-induced drug resistance in human colorectal cancer cell lines HT29 and HCT116. Our results demonstrate a significant autophagy expression in CRC cells after an oxaliplatin treatment. Administration of oxaliplatin to human CRC cells significantly enhanced the expression of HMGB1, which regulated the autophagy response and negatively regulate the cell apoptosis. Moreover, a decreased oxaliplatin -induced autophagy response and an increased apoptosis level were detected in stable CRC cells harboring HMGB1 shRNA. Then we noted that HMGB1 significantly induced extracellular signal-regulated kinase (ERK)/Extracellular signal-regulated kinase kinase (MEK) phosphorylation. Taken together, these data suggest that HMGB1-mediated autophagy modulates sensitivity of colorectal cancer cells to oxaliplatin via MEK/ERK signaling pathway.

Drug specific resistance to oxaliplatin is associated with apoptosis defect in a cellular model of colon carcinoma

To investigate acquired resistance to oxaliplatin, we selected two resistant clones from the HCT116 cell line. We found that the resistant phenotype was associated with resistance to oxaliplatin-induced apoptosis as demonstrated by FACS analysis and by Western blotting of caspase 3 activation. In addition, the resistant phenotype showed a concomitant resistance to lonidamine and arsenic trioxide which are inducers of mitochondrial apoptosis. Furthermore, a complete loss of Bax expression due to a frameshift mutation was observed in the most resistant clone. Taken together, these findings suggest that altered mitochondrial-mediated apoptosis could play a role in oxaliplatin resistance.

GP letter writing in colorectal cancer: a qualitative study

BACKGROUND

The usual mode of communication with the specialist in the UK is a referral letter. Letters now primarily document the GPs' concerns for the patient and are no longer required to persuade the specialist to offer an appointment. The content of referral letters from GPs has failed to satisfy specialists responding to a series of surveys. Evidence suggests that GPs who improve their letters to specialists also refer more cases with significant pathology.

AIMS

The aims of this research are to explore the factors that may influence GPs in writing the referral letter when consulting patients presenting with lower bowel symptoms.

METHODS

A convenience sample of twelve GPs was interviewed in Nottinghamshire and inner city Sheffield practices. A framework approach was utilised in the analysis of data. Data from the interviews followed the prescribed steps, including: familiarisation, identifying a thematic framework, indexing, charting and mapping, and interpretation.

RESULTS

The thematic framework reflected four major themes. These were: (1) the nature and content of referral letters, (2) knowledge about colorectal cancer, (3) issues relating to the quality of referral letters in colorectal cases and (4) factors that effect the use of guidelines for referral.

CONCLUSIONS

GPs only have very short consultations in which to address many and complex issues. Pre-referral assessment in colorectal cases includes intimate examination of the patient. Therefore the writing of the letter of referral is often postponed until long after the patient has left the GP's office. Some GPs do not believe the consultant reads the letter of referral. However, GPs are keen to provide best care and welcome feedback about the quality of their letters. They acknowledge the responsibility to communicate with colleagues effectively and have differing ideas about what constitutes an adequate referral letter.