Missed opportunities for physical activity management at key points throughout the chemotherapy pathway for colorectal survivors: an observational interview study

PURPOSE

Physical activity (PA) is central to self-management for people with colorectal cancer (CRC) to support health behaviour and function secondary to cancer treatment. However, there is limited evidence on how health professionals (HPs) promote PA during cancer treatment. This study aimed to investigate how and when PA is promoted throughout the chemotherapy pathway among colorectal cancer survivors.

METHODS

A qualitative study was conducted with adults with CRC receiving chemotherapy at a large cancer centre. Cross-sectional observation of clinical consultations was conducted at four points during the chemotherapy pathway: prior, midpoint, final cycle, and 8 weeks following chemotherapy. Following completion of treatment, audio-recorded, semi-structured interviews were conducted with patients and HPs and transcribed verbatim. Codes and themes were identified and triangulated from all the data using framework analysis. Observational themes are reported and complimented by interview data.

RESULTS

Throughout the chemotherapy pathway (pre, midpoint, end), many opportunities were missed by HPs to promote PA as a beneficial means to maintain functioning and ameliorate cancer treatment side effects. When discussed, PA levels were used only to determine fitness for future oncological treatment. No PA promotion was observed despite patients reporting low PA levels or treatment side effects. Post-treatment, PA promotion was more routinely delivered by HPs, as evidenced by problem-solving and onward referrals to relevant HPs.

CONCLUSION

PA promotion was largely absent during treatment despite it being a key component of patient self-management following treatment. This suggests considerable missed opportunities for HPs to provide cancer survivors with PA evidence-based interventions. Further research is necessary to identify how best to ensure PA is promoted throughout the cancer journey.

IMPLICATION FOR CANCER SURVIVORS

These findings suggest many may not be receiving support to be physically active during treatment.

Real World Evidence: A Quantitative and Qualitative Glance at Participant Feedback from a Free-Response Survey Investigating Experiences of a Structured Exercise Intervention for Men with Prostate Cancer

AIM

To explore patient experiences of a structured exercise intervention for men with prostate cancer (PCa).

SAMPLE

41 men with either localised or advanced PCa who had been referred for a structured exercise programme by their physician and then subsequently consented to a telephone survey.

METHOD

Participants underwent a 10-week supervised exercise programme within a large cancer centre hospital consisting of 8 sessions. They then completed a short multiple choice telephone survey, elaborating on their responses where appropriate. Views expressed by participants were analysed using an affinity diagram and common themes were identified.

RESULTS

Feedback from our telephone surveys was consistently positive and suggests that the structured exercise intervention provides exercise confidence, motivation to exercise, and social support and promotes positive health behaviour change in the context of exercise. Individual differences arose amongst participants in their perceived utility of the intervention, with 73.3% expressing a preference for structured exercise classes and 19.5% expressing a preference for exercising independently.

CONCLUSION

Design of a structured exercise intervention for patients with PCa should embrace the positive aspects outlined here but consider patients' individual differences. Ongoing feedback from patients should be utilised alongside traditional study designs to inform intervention design in this area.

The genome sequence of Schizosaccharomyces pombe

We have sequenced and annotated the genome of fission yeast (Schizosaccharomyces pombe), which contains the smallest number of protein-coding genes yet recorded for a eukaryote: 4,824. The centromeres are between 35 and 110 kilobases (kb) and contain related repeats including a highly conserved 1.8-kb element. Regions upstream of genes are longer than in budding yeast (Saccharomyces cerevisiae), possibly reflecting more-extended control regions. Some 43% of the genes contain introns, of which there are 4,730. Fifty genes have significant similarity with human disease genes; half of these are cancer related. We identify highly conserved genes important for eukaryotic cell organization including those required for the cytoskeleton, compartmentation, cell-cycle control, proteolysis, protein phosphorylation and RNA splicing. These genes may have originated with the appearance of eukaryotic life. Few similarly conserved genes that are important for multicellular organization were identified, suggesting that the transition from prokaryotes to eukaryotes required more new genes than did the transition from unicellular to multicellular organization.

Functional characterization of the fission yeast Start-specific transcription factor Res2

In the fission yeast Schizosaccharomyces pombe, transcriptional activation at Start is mediated by complexes that bind the MCB. Two such complexes have been identified; both contain the Cdc10 protein in partnership with either the Res1 or Res2 protein. Characterization of null mutants suggests that the Res1-Cdc10 complex predominantly functions in mitotic cells whereas the Res2-Cdc10 complex is required for meiosis and spore formation. Here we have characterized the functional domains of the Res2 protein. The N-terminus is both necessary and sufficient for DNA binding, whereas the C-terminus is the region involved in the interaction with the Cdc10 protein. The centrally located ankyrin repeats are dispensable for both functions. Res2 binds to DNA as a dimer. In addition, complexes containing both Res1 and Res2 can form and bind to DNA in vitro. Furthermore, the major MCB-specific complex detected in extracts from wild-type cells contains Res1 and Res2; the complex is lost when either gene is deleted and can be recognized by antibodies specific to both proteins. In order to understand the basis for the specific function of Res2 in meiosis, hybrids between Res1 and Res2 were constructed and their functions analysed. The results indicate an absolute requirement for the Res2 C-terminus for normal meiosis to occur whereas the origin of the DNA-binding region is irrelevant. The implications of these results for the regulation of the MCB-binding complexes will be discussed.

Two GC boxes (Sp1 sites) are involved in regulation of the activity of the epithelium-specific MUC1 promoter

In this report, we have analyzed the function of two Sp1 sites present in the epithelium-specific MUC1 promoter. Using promoter-reporter gene (CAT) constructs, we found that mutagenesis of either of the Sp1 binding motifs at -576/-568 and -99/-90, reduced transcription in MUC1-expressing epithelial cell lines. However, abolition of the binding site at -99/-91 by mutagenesis also resulted in increased transcriptional activity in non-epithelial cell lines, suggesting involvement of the site in tissue-specific expression. In vitro binding assays revealed a novel binding motif at -101/-89 (AGGGGGCGGGGTT), which overlaps but differs from the Sp1 consensus motif by having an adenine residue in the 5'-flanking sequence. The 5'-flanking sequence appeared to be important for binding of an Sp1-unrelated factor (SpA) but not for binding of Sp1. Site-directed mutagenesis of the motif into a site able to bind Sp1, but unable to bind SpA, resulted in an increased level of transcription of the CAT reporter gene in all cell lines tested, suggesting a repressive effect of the novel factor on transcription. The ratio between the Sp1 and SpA binding activity in nuclear extracts correlated with both promoter activity and the levels of endogenous transcription in different breast cancer cell lines. Our results are consistent with the idea that the relative activities of the two factors may be involved in the up-regulation of expression of the MUC1 gene seen in breast and other carcinomas.

Regular low-dose intravenous iron therapy improves response to erythropoietin in haemodialysis patients

BACKGROUND

Erythropoietin (Epo) is an effective but expensive treatment for anaemia in patients with chronic renal failure. Hyporesponsiveness to Epo, particularly in haemodialysis patients, is most commonly due to a functional iron deficiency, which is difficult to monitor reliably.

METHODS

Forty-six stable haemodialysis patients, receiving Epo therapy, were commenced on regular low-dose intravenous iron (sodium ferric gluconate complex) at a dose of 62.5 mg/5 ml given as a slow injection post-dialysis twice weekly, weekly, or fortnightly, according to their serum ferritin levels. Haemoglobin, serum ferritin, Epo dose, and iron dose were measured at 6-weekly intervals over a 6-month period.

RESULTS

At the beginning of the study, 12 patients in the group had ferritin levels of less than 100 microg/l, and were thus considered to potentially have an absolute iron deficiency. The study group was therefore split into two subgroups for the purpose of analysis, i.e. the 12 patients with ferritin levels of less than 100 microg/l at the start of the study or 'low ferritin group', and the remaining 34 patients with ferritin levels of greater than 100 microg/l at the start of the study or 'normal ferritin group'. In the low ferritin group (n=12), intravenous iron therapy increased serum ferritin levels, and produced a significant rise in haemoglobin, and a significant reduction in Epo dose. (Ferritin pre-iron, median (range) 68 (20-96) microg/l; post-iron, 210.5 (91-447) microg/l, P<0. 003, Wilcoxon. Haemoglobin pre-iron, 10.05 (8.2-11.9) g/dl; post-iron, 11.0 (9.9-11.9) g/dl, P<0.03. Epo dose pre-iron, 9000 (4000-30 000)-i.u./week, P<0.05). Similar results were obtained in the normal ferritin group (n=34) following intravenous iron therapy, with significant increases in serum ferritin levels and haemoglobin concentrations, and a significant reduction in Epo dose. (Ferritin pre-iron, 176 (103-519) microg/l; post-iron, 304.5 (121-792) microg/l, P<0.0001. Haemoglobin pre-iron, 9.85 (6.5-12.8) g/dl; post-iron: 11.25 (9.9-13.3) g/dl, P<0.0001. Epo dose pre-iron, 6000 (2000-15 000) i.u./week; post-iron, 4000 (0-15 000)-i.u./week, P<0. 005).

CONCLUSION

Regular intravenous iron supplementation in haemodialysis patients improves the response to Epo therapy.

Analysis of the tissue-specific promoter of the MUC1 gene

The 5'-sequences flanking the human MUC1 gene have been analyzed for their ability to direct expression of a reporter gene (the chloramphenicol acetyltransferase gene (CAT)) in cell lines that normally express or do not express the MUC1 gene. A construct containing 2.9 kilobase pairs of MUC1 5'-flanking sequence sequence showed expression of CAT in breast and pancreatic cell lines but not in the non-epithelial cell lines HT-1080, SK23, and HTB96. Deletion analysis showed that maximum expression was obtained in ZR-75 (breast cancer line) and HPAF (pancreatic cancer line) with only 743 base pairs of 5'-flanking sequence. Sequences within 1.6 kilobase pairs of the transcriptional start site showed enhancing activity in a vector carrying an enhancerless SV40 promoter. Analysis of proximal 5'-sequences in a promoterless CAT vector carrying the SV40 enhancer showed that sequences between -60 and -150 were crucial for tissue-specific expression. An Sp1 site at -99/-90 and an E box (E-MUC1) at -84/-64 in this region were shown by mutational analysis to play a role in the regulation of transcription. Gel shift analysis with oligonucleotides and nuclear extracts of ZR-75 showed protein binding to both of these sites. Sp1 binding activity was similar in ZR-75 and HT1080 cells, whereas binding of factors to the E-MUC1 oligonucleotide revealed quantitative and qualitative differences between epithelial and non-epithelial cells.

Tissue-specific expression of a human polymorphic epithelial mucin (MUC1) in transgenic mice

The human MUC1 gene codes for the core protein of a mucin which is expressed by glandular epithelia and the carcinomas which develop from these tissues. The core protein is aberrantly glycosylated in cancers, and some antibodies show specificity in their reactions with the cancer-associated mucin, which also contains epitopes recognized by T-cells from breast and pancreatic cancer patients. For evaluating the potential use of mucin-reactive antibodies and mucin-based immunogens in cancer patients, a mouse model, expressing the MUC1 gene product PEM (polymorphic epithelial mucin) as a self antigen, would be extremely useful. To this end, we have developed transgenic mouse strains expressing the human MUC1 gene product in a tissue-specific manner. The TG4 mouse strain was established using a 40-kilobase fragment containing 4.5 kilobases of 5' and 27 kilobases of 3' flanking sequence. The TG18 strain was developed using a 10.6-kilobase SacII fragment from the 40-kilobase fragment; this fragment contained 1.6 kilobases of 5' sequence and 1.9 kilobases of 3' flanking sequence. Both strains showed tissue specificity of expression of the MUC1 gene, which was very similar to the profile of expression seen in human tissues. The antibody SM-3 is directed to a core protein epitope, which is selectively exposed in breast cancers and which shows a more restricted distribution on normal human tissues. It was established that the distribution of the SM-3 epitope of PEM in the tissues of the transgenic mice is similar to that seen in humans. The transgenic mouse strains described here should form the basis for the development of a preclinical model for the evaluation of PEM-based antigens and of antibodies directed to PEM in cancer therapy.

Structure and biology of a carcinoma-associated mucin, MUC1

Although mucins have been studied at the biochemical and biophysical level for some time, attempts to define their structures in detail were only partially successful because of their size and complexity. The advent of monoclonal antibodies reactive with these molecules introduced a new approach to structural studies by defining antigenic epitopes, by allowing purification of the mucin molecules by affinity chromatography, and by providing a means to clone genes coding for the core proteins. By their profile of reactivity with the normal and cancer-associated mucin in a particular tissue, the antibodies also defined a difference in the mucin derived from the two sources. It is now clear that this difference lies in the carbohydrate side chains, as the core proteins are identical. Because the mucins are tumor-associated antigens and the cancer mucins can express epitopes that are relatively tumor specific, this family of molecules is now being intensively studied. There is also considerable interest in elucidating the normal function of the mucin and in determining whether, through an altered structure, this function is subverted in malignancy. In the next few years we should expect that the structure of other mucins will be defined in the same detail as the product of the MUC1 gene. We should also expect to see the continued application of mucin-reactive antibodies in the clinic and the investigation of mucins as agents for immunotherapy of some cancers. As to the function(s) of these molecules, perhaps we will learn enough in the future to make a critical reappraisal of the name.

Structure and expression of the human polymorphic epithelial mucin gene: an expressed VNTR unit

The human polymorphic epithelial mucin (PEM) is expressed apically by glandular epithelium and by the carcinomas that develop from these tissues. Previously isolated cDNA clones revealed that the core protein contained a large domain consisting of variable numbers of 60 bp tandem repeats (TR), making it an expressed minisatellite. We now report the full genomic sequence of the PEM gene, including 803 bp of 5' flanking sequence. The gene is composed of 7 exons and varies in size from approximately 4 to approximately 7 kb, depending on the number of tandem repeats in exon 2. Expression of PEM was obtained from a genomic clone in an Epstein-Barr virus based vector, after transfection into a human epithelial cell line, indicating the presence of effective regulatory sequences in this clone.

Molecular cloning and expression of human tumor-associated polymorphic epithelial mucin

Human mammary cells present on the cell surface a polymorphic epithelial mucin (PEM) which is developmentally regulated and aberrantly expressed in tumors. PEM carries tumor-associated epitopes recognized by the monoclonal antibodies HMFG-1, HMFG-2, and SM-3. Previously isolated partial cDNA clones revealed that the core protein contained a large domain consisting of variable numbers of 20-amino acid repeat units. We now report the full sequence for PEM, as deduced from cDNA sequences. The encoded protein consists of three distinct regions: the amino terminus consisting of a putative signal peptide and degenerate repeats; the major portion of the protein which is the tandem repeat region; the carboxyl terminus consisting of degenerate tandem repeats and a unique sequence containing a transmembrane sequence and a cytoplasmic tail. Potential O-glycosylation sites (serines or threonines) make up more than one-fourth of the amino acids. Length variations in the tandem repeat result in PEM being an expressed variable number tandem repeat locus. Tandem repeats appear to be a general characteristic of mucin core proteins.