Cathepsin B promotes colorectal tumorigenesis, cell invasion, and metastasis.

Cathepsin B is a cysteine proteinase that primarily functions as an endopeptidase within endolysosomal compartments in normal cells. However, during tumoral expansion, the regulation of cathepsin B can be altered at multiple levels, thereby resulting in its overexpression and export outside of the cell. This may suggest a possible role of cathepsin B in alterations leading to cancer progression. The aim of this study was to determine the contribution of intracellular and extracellular cathepsin B in growth, tumorigenesis, and invasion of colorectal cancer (CRC) cells. Results show that mRNA and activated levels of cathepsin B were both increased in human adenomas and in CRCs of all stages. Treatment of CRC cells with the highly selective and non-permeant cathepsin B inhibitor Ca074 revealed that extracellular cathepsin B actively contributed to the invasiveness of human CRC cells while not essential for their growth in soft agar. Cathepsin B silencing by RNAi in human CRC cells inhibited their growth in soft agar, as well as their invasion capacity, tumoral expansion, and metastatic spread in immunodeficient mice. Higher levels of the cell cycle inhibitor p27(Kip1) were observed in cathepsin B-deficient tumors as well as an increase in cyclin B1. Finally, cathepsin B colocalized with p27(Kip1) within the lysosomes and efficiently degraded the inhibitor. In conclusion, the present data demonstrate that cathepsin B is a significant factor in colorectal tumor development, invasion, and metastatic spreading and may, therefore, represent a potential pharmacological target for colorectal tumor therapy.

Adjuvant treatment for endometrial cancer: literature review and recommendations by the Comité de l'évolution des pratiques en oncologie (CEPO).

OBJECTIVE: Despite the very good prognosis of endometrial cancer, a number of patients with localized disease relapse following surgery. Therefore, various adjuvant therapeutic approaches have been studied. The objective of this review is to evaluate the efficacy and safety of neoadjuvant and adjuvant therapies in patients with resectable endometrial cancer and to develop evidence-based recommendations. METHODS: A review of the scientific literature published between January 1990 and June 2012 was performed. The search was limited to published phase III clinical trials and meta-analyses evaluating the efficacy of neoadjuvant or adjuvant therapies in patients with endometrial carcinoma or carcinosarcoma. A total of 23 studies and five meta-analyses were identified. RESULTS: The selected literature showed that in patients with a low risk of recurrence, post-surgical observation is safe and recommended in most cases. There are several therapeutic modalities available for treatment of endometrial cancers with higher risk of recurrence, including vaginal brachytherapy, external beam radiotherapy, chemotherapy, or a combination of these. CONCLUSIONS: Considering the evidence available to date, the CEPO recommends the following: (1)post-surgical observation for most patients with a low recurrence risk; (2)adjuvant vaginal brachytherapy for patients with an intermediate recurrence risk; (3)adjuvant pelvic radiotherapy with or without vaginal brachytherapy for patients with a high recurrence risk; addition of adjuvant chemotherapy may be considered as an option for selected patients (excellent functional status, no significant co-morbidities, poor prognostic factors); (4)adjuvant chemotherapy and pelvic radiotherapy with or without brachytherapy and para-aortic irradiation for patients with advanced disease;

Laparoscopic versus open surgery for the treatment of colorectal cancer: a literature review and recommendations from the Comité de l'évolution des pratiques en oncologie.

BACKGROUND: Adoption of the laparoscopic approach for colorectal cancer treatment has been slow owing to initial case study results suggesting high recurrence rates at port sites. The use of laparoscopic surgery for colorectal cancer still raises a number of concerns, particularly with the technique's complexity, learning curve and longer duration. After exploring the scientific literature comparing open and laparoscopic surgery for the treatment of colorectal cancer with respect to oncologic efficacy and shortterm outcomes, the Comité de l'évolution des pratiques en oncologie (CEPO) made recommendations for surgical practice in Quebec. METHODS: Scientific literature published from January 1995 to April 2012 was reviewed. Phase III clinical trials and meta-analyses were included. RESULTS: Sixteen randomized trials and 10 meta-analyses were retrieved. Analysis of the literature confirmed that for curative treatment of colorectal cancer, laparoscopy is not inferior to open surgery with respect to survival and recurrence rates. Moreover, laparoscopic surgery provides short-term advantages, including a shorter hospital stay, reduced analgesic use and faster recovery of intestinal function. However, this approach does require a longer operative time. CONCLUSION: Considering the evidence, the CEPO recommends that laparoscopic resection be considered an option for the curative treatment of colon and rectal cancer; that decisions regarding surgical approach take into consideration surgeon experience, tumour stage, potential contraindications and patient expectations; and that laparoscopic resection for rectal cancer be performed only by appropriately trained surgeons who perform a sufficient volume annually to maintain competence.

CONTEXTE: L'adoption de la laparoscopie pour traiter le cancer colorectal se fait lentement à cause des résultats des premières études de cas qui indiquent des taux élevés de récidive aux sites d'intervention. La laparoscopie pour traiter le cancer colorectal soulève toujours de nombreuses préoccupations, particulièrement en raison de la complexité de la technique, de la courbe d'apprentissage, et de la durée de la chirurgie. Après avoir étudié des publications scientifiques comparant l'efficacité oncologique et les résultats à court terme de la laparoscopie à ceux de la chirurgie ouverte pour le traitement du cancer colorectal, le Comité de l'évolution des pratiques en oncologie (CEPO) a formulé des recommandations pour la pratique chirurgicale au Québec. MÉTHODES: Une revue des écrits scientifiques publiés entre janvier 1995 et avril 2012 a été effectuée. Seuls les essais cliniques de phase III et les méta-analyses ont été répertoriés. RÉSULTANTS: Seize essais randomisés et 10 méta-analyses ont été retenus. L'analyse des publications a confirmé que pour le traitement curatif du cancer colorectal, la laparoscopie n'est pas inférieure à la chirurgie ouverte pour ce qui est des taux de survie et de récidive. La laparoscopie offre de plus des avantages à court terme, y compris une hospitalisation de moins longue durée, une réduction de l'usage d'analgésiques et un rétablissement plus rapide de la fonction intestinale. Cette intervention prend toutefois plus de temps. CONCLUSIONS: Compte tenu des données probantes, le CEPO recommande d'envisager la résection laparoscopique comme technique curative possible du cancer colorectal et que les décisions sur la méthode chirurgicale tiennent compte de l'expérience du chirurgien, du stade de la tumeur, des contre-indications possibles et des attentes du patient. Dans le cas de la résection laparoscopique du cancer du rectum, le CEPO recommande qu'elle ne soit pratiquée que par des chirurgiens ayant reçu la formation nécessaire et qui pratiquent suffisamment d'interventions par année pour maintenir leur compétence.

Inequalities in survival and care across social determinants of health in a cohort of advanced lung cancer patients in Quebec (Canada): A high-resolution population-level analysis.

BACKGROUND: Advanced lung cancer patients exposed to breakthrough therapies like EGFR tyrosine kinase inhibitors (EGFR-TKI) may experience social inequalities in survival, partly from differences in care. This study examined survival by neighborhood-level socioeconomic and sociodemographic status, and geographical location of advanced lung cancer patients who received gefitinib, an EGFR-TKI, as first-line palliative treatment. Differences in the use and delay of EGFR-TKI treatment were also examined. METHODS: Lung cancer patients receiving gefitinib from 2001 to 2019 were identified from Quebec's health administrative databases. Accounting for age and sex, estimates were obtained for the median survival time from treatment to death, the probability of receiving osimertinib as a second EGFR-TKI, and the median time from biopsy to receiving first-line gefitinib. RESULTS: Among 457 patients who received first-line treatment with gefitinib, those living in the most materially deprived areas had the shortest median survival time (ratio, high vs. low deprivation: 0.69; 95% CI: 0.47-1.04). The probability of receiving osimertinib as a second EGFR-TKI was highest for patients from immigrant-dense areas (ratio, high vs. lowdensity: 1.95; 95% CI: 1.26-3.36) or from Montreal (ratio, other urban areas vs. Montreal: 0.39; 95% CI: 0.16-0.71). The median wait time for gefitinib was 1.27 times longer in regions with health centers peripheral to large centers in Quebec or Montreal in comparison to regions with university-affiliated centers (95% CI: 1.09-1.54; n = 353). CONCLUSION: This study shows that real-world variations in survival and treatment exist among advanced lung cancer patients in the era of breakthrough therapies and that future research on inequalities should also focus on this population.

Advanced Lung Cancer Patients' Use of EGFR Tyrosine Kinase Inhibitors and Overall Survival: Real-World Evidence from Quebec, Canada.

EGFR tyrosine kinase inhibitors (EGFR-TKIs) are breakthrough palliative treatments for advanced lung cancer patients with tumors harboring mutations in the EGFR gene. Using healthcare administrative data, three cohorts were created to describe the use of three EGFR-TKIs that are publicly funded in Quebec for specific indications (i.e., 1st-line gefitinib, 1st-line afatinib, and post-EGFR-TKI osimertinib). The main objective was to compare overall survival (OS) among patients receiving these treatments to those in previous experimental and real-world studies. The patients who received EGFR-TKIs for indications of interest between 1 April 2001, and 31 March 2019 (or 31 March 2020, for post-EGFR-TKI osimertinib) were included to estimate the Kaplan-Meier-based median OS for each cohort. An extensive literature search was conducted to include comparable studies. For the gefitinib 1st-line (n = 457), the afatinib 1st-line (n = 80), and the post-EGFR-TKI osimertinib (n = 119) cohorts, we found a median OS (in months) of 18.9 (95%CI: 16.3-21.9), 26.6 (95%CI: 13.7-NE) and 19.9 (95%CI: 17.4-NE), respectively. Out of the 20 studies that we retained from the literature review and where comparisons were feasible, 17 (85%) had similar OS results, which further confirms the value of these breakthrough therapies in real-world clinical practice.

Epithelial polarity proteins regulate Drosophila tracheal tube size in parallel to the luminal matrix pathway.

Regulation of epithelial tube size is critical for organ function. However, the mechanisms of tube size control remain poorly understood. In the Drosophila trachea, tube dimensions are regulated by a luminal extracellular matrix (ECM). ECM organization requires apical (luminal) secretion of the protein Vermiform (Verm), which depends on the basolateral septate junction (SJ). Here, we show that apical and basolateral epithelial polarity proteins interact to control tracheal tube size independently of the Verm pathway. Mutations in yurt (yrt) and scribble (scrib), which encode SJ-associated polarity proteins, cause an expansion of tracheal tubes but do not disrupt Verm secretion. Reducing activity of the apical polarity protein Crumbs (Crb) suppresses the length defects in yrt but not scrib mutants, suggesting that Yrt acts by negatively regulating Crb. Conversely, Crb overexpression increases tracheal tube dimensions. Reducing crb dosage also rescues tracheal size defects caused by mutations in coracle (cora), which encodes an SJ-associated polarity protein. In addition, crb mutations suppress cora length defects without restoring Verm secretion. Together, these data indicate that Yrt, Cora, Crb, and Scrib operate independently of the Verm pathway. Our data support a model in which Cora and Yrt act through Crb to regulate epithelial tube size.

Activation of Cdk2 stimulates proteasome-dependent truncation of tyrosine phosphatase SHP-1 in human proliferating intestinal epithelial cells.

SHP-1 is expressed in the nuclei of intestinal epithelial cells (IECs). Increased SHP-1 expression and phosphatase activity coincide with cell cycle arrest and differentiation in these cells. Suspecting the tumor-suppressive properties of SHP-1, a yeast two-hybrid screen of an IEC cDNA library was conducted using the full-length SHP-1 as bait. Characterization of many positive clones revealed sequences identical to a segment of the Cdk2 cDNA sequence. Interaction between SHP-1 and Cdk2 was confirmed by co-immunoprecipitations whereby co-precipitated Cdk2 phosphorylated SHP-1 protein. Inhibition of Cdk2 (roscovitine) or proteasome (MG132) was associated with an enhanced nuclear punctuate distribution of SHP-1. Double labeling localization studies with signature proteins of subnuclear domains revealed a co-localization between the splicing factor SC35 and SHP-1 in bright nucleoplasmic foci. Using Western blot analyses with the anti-SHP-1 antibody recognizing the C terminus, a lower molecular mass species of 45 kDa was observed in addition to the full-length 64-65-kDa SHP-1 protein. Treatment with MG132 led to an increase in expression of the full-length SHP-1 protein while concomitantly leading to a decrease in the levels of the lower mass 45-kDa molecular species. Further Western blots revealed that the 45-kDa protein corresponds to the C-terminal portion of SHP-1 generated from proteasome activity. Mutational analysis of Tyr(208) and Ser(591) (a Cdk2 phosphorylation site) residues on SHP-1 abolished the expression of the amino-truncated 45-kDa SHP-1 protein. In conclusion, our results indicate that Cdk2-associated complexes, by targeting SHP-1 for proteolysis, counteract the ability of SHP-1 to block cell cycle progression of IECs.

Cdk2-dependent phosphorylation of homeobox transcription factor CDX2 regulates its nuclear translocation and proteasome-mediated degradation in human intestinal epithelial cells.

By having demonstrated previously that p27(Kip1), a potent inhibitor of G(1) cyclin-cyclin-dependent kinases complexes, increases markedly during intestinal epithelial cell differentiation, we examined the effect of p27(Kip1) on the activity of the transcription factor CDX2. The present results revealed the following. 1) p27(Kip1) interacts with the CDX2 transcription factor. 2) In contrast to CDX2 mRNA levels, CDX2 protein expression levels significantly increased as soon as Caco-2/15 cells reached confluence, slowed their proliferation, and began their differentiation. The mechanism of CDX2 regulation is primarily related to protein stability, because inhibition of proteasome activity increased CDX2 levels. The half-life of CDX2 protein was significantly enhanced in differentiated versus undifferentiated proliferative intestinal epithelial cells. 3) Cdk2 interacted with CDX2 and phosphorylated CDX2, as determined by pull-down glutathione S-transferase and immunoprecipitation experiments with proliferating undifferentiated Caco-2/15 cell extracts. 4) Treatment of Caco-2/15 cells with MG132 (a proteasome inhibitor) and (R)-roscovitine (a specific Cdk2 inhibitor) induced an increase in CDX2 protein levels. 5) Conversely, ectopic expression of Cdk2 resulted in decreased expression of CDX2 protein. 6) Of note, treatment of proliferative Caco-2/15 cells with (R)-roscovitine or leptomycin (an inhibitor of nuclear export through CRM1) led to an accumulation of CDX2 into the nucleus. These data suggest that CDX2 undergoes CRM1-dependent nuclear export and cytoplasmic degradation in cells in which Cdk2 is activated, such as in proliferative intestinal epithelial cells. The targeted degradation of CDX2 following its phosphorylation by Cdk2 identifies a new mechanism through which CDX2 activity can be regulated in coordination with the cell cycle machinery.