High CD142 Level Marks Tumor-Promoting Fibroblasts with Targeting Potential in Colorectal Cancer.

Colorectal cancer (CRC) has a high incidence and is one of the leading causes of cancer-related death. The accumulation of cancer-associated fibroblasts (CAF) induces an aggressive, stem-like phenotype in tumor cells, and it indicates a poor prognosis. However, cellular heterogeneity among CAFs and the targeting of both stromal and CRC cells are not yet well resolved. Here, we identified CD142high fibroblasts with a higher stimulating effect on CRC cell proliferation via secreting more hepatocyte growth factor (HGF) compared to CD142low CAFs. We also found that combinations of inhibitors that had either a promising effect in other cancer types or are more active in CRC compared to normal colonic epithelium acted synergistically in CRC cells. Importantly, heat shock protein 90 (HSP90) inhibitor selected against CD142high fibroblasts, and both CRC cells and CAFs were sensitive to a BCL-xL inhibitor. However, targeting mitogen-activated protein kinase kinase (MEK) was ineffective in fibroblasts, and an epigenetic inhibitor selected for a tumor cell population with markers of aggressive behavior. Thus, we suggest BCL-xL and HSP90 inhibitors to eliminate cancer cells and decrease the tumor-promoting CD142high CAF population. This may be the basis of a strategy to target both CRC cells and stromal fibroblasts, resulting in the inhibition of tumor relapse.

IFITM1 expression determines extracellular vesicle uptake in colorectal cancer.

The majority of colorectal cancer (CRC) patients carry mutations in the APC gene, which lead to the unregulated activation of the Wnt pathway. Extracellular vesicles (EV) are considered potential therapeutic tools. Although CRC is a genetically heterogeneous disease, the significance of the intra-tumor heterogeneity in EV uptake of CRC cells is not yet known. By using mouse and patient-derived organoids, the currently available best model of capturing cellular heterogeneity, we found that Apc mutation induced the expression of interferon-induced transmembrane protein 1 (Ifitm1), a membrane protein that plays a major role in cellular antiviral responses. Importantly, organoids derived from IFITM1high CRC cells contained more proliferating cells and they had a markedly reduced uptake of fibroblast EVs as compared to IFITM1low/- cells. In contrast, there was no difference in the intensity of EV release between CRC subpopulations with high and low IFITM1 levels. Importantly, the difference in cell proliferation between these two subpopulations disappeared in the presence of fibroblast-derived EVs, proving the functional relevance of the enhanced EV uptake by IFITM1low CRC cells. Furthermore, inactivating IFITM1 resulted in an enhanced EV uptake, highlighting the importance of this molecule in establishing the cellular difference for EV effects. Collectively, we identified CRC cells with functional difference in their EV uptake ability that must be taken into consideration when using EVs as therapeutic tools for targeting cancer cells.

Shared extracellular vesicle miRNA profiles of matched ductal pancreatic adenocarcinoma organoids and blood plasma samples show the power of organoid technology.

Extracellular vesicles (EV) are considered as a promising diagnostic tool for pancreatic ductal adenocarcinoma (PDAC), a disease with a poor 5-year survival that has not improved in the past years. PDAC patient-derived 3D organoids maintain the intratumoral cellular heterogeneity, characteristic for the tumor in vivo.Thus, they represent an ideal in vitro model system to study human cancers. Here we show that the miRNA cargo of EVs from PDAC organoids largely differs among patients. However, we detected a common set of EV miRNAs that were present in matched organoids and blood plasma samples of individual patients. Importantly, the levels of EV miR-21 and miR-195 were higher in PDAC blood EV preparations than in healthy controls, albeit we found no difference compared to chronic pancreatitis (CP) samples. In addition, here we report that the accumulation of collagen I, a characteristic change in the extracellular matrix (ECM) in both CP and PDAC, largely increases EV release from pancreatic ductal organoids. This provides a possible explanation why both CP and PDAC patient-derived plasma samples have an elevated amount of CD63 + EVs. Collectively, we show that PDAC patient-derived organoids represent a highly relevant model to analyze the cargo of tumor cell-derived EVs. Furthermore, we provide evidence that not only driver mutations, but also changes in the ECM may critically modify EV release from pancreatic ductal cells.

CD44 Expression Intensity Marks Colorectal Cancer Cell Subpopulations with Different Extracellular Vesicle Release Capacity.

Extracellular vesicles (EV) are released by virtually all cells and they transport biologically important molecules from the release site to target cells. Colorectal cancer (CRC) is a leading cause of cancer-related death cases, thus, it represents a major health issue. Although the EV cargo may reflect the molecular composition of the releasing cells and thus, EVs may hold a great promise for tumor diagnostics, the impact of intratumoral heterogeneity on the intensity of EV release is still largely unknown. By using CRC patient-derived organoids that maintain the cellular and molecular heterogeneity of the original epithelial tumor tissue, we proved that CD44high cells produce more organoids with a higher proliferation intensity, as compared to CD44low cells. Interestingly, we detected an increased EV release by CD44high CRC cells. In addition, we found that the miRNA cargos of CD44high and CD44low cell derived EVs largely overlapped and only four miRNAs were specific for one of the above subpopulations. We observed that EVs released by CD44high cells induced the proliferation and activation of colon fibroblasts more strongly than CD44low cells. However, this effect was due to the higher EV number rather than to the miRNA cargo of EVs. Collectively, we identified CRC subpopulations with different EV releasing capabilities and we proved that CRC cell-released EVs have a miRNA-independent effect on fibroblast proliferation and activation.

Extracellular vesicles transmit epithelial growth factor activity in the intestinal stem cell niche.

Extracellular vesicles (EV) are membrane-surrounded vesicles that represent a novel way of intercellular communication by carrying biologically important molecules in a concentrated and protected form. The intestinal epithelium is continuously renewed by a small proliferating intestinal stem cell (ISC) population, residing at the bottom of the intestinal crypts in a specific microenvironment, the stem cell niche. By using 3D mouse and human intestinal organoids, we show that intestinal fibroblast-derived EVs are involved in forming the ISC niche by transmitting Wnt and epidermal growth factor (EGF) activity. With a mouse model that expresses EGFP in the Lgr5+ ISCs, we prove that loss in ISC number in the absence of EGF is prevented by fibroblast-derived EVs. Furthermore, we demonstrate that intestinal fibroblast-derived EVs carry EGF family members, such as amphiregulin. Mechanistically, blocking EV-bound amphiregulin inhibited the EV-induced survival of organoids. In contrast, EVs have no role in transporting R-Spondin, a critical niche factor amplifying Wnt signaling. Collectively, we prove the important role of fibroblast-derived EVs as a novel transmission mechanism of factors in the normal ISC niche.

Short-term advantages of ELAPE over APR.

INTRODUCTION: Conventional abdominoperineal resection (APR) has a high rate of local recurrence. Extralevator abdominoperineal excision (ELAPE) can potentially diminish the rate of intraoperative tumour perforation (IOTP) and can provide wider circumferential resection margins (CRM) but at the price of higher perineal complication rate. The aim of our study was to compare the short term results of conventional APR to ELAPE. MATERIALS AND METHODS: Thirty-five consecutively operated APRs compared to 38 also consecutively operated ELAPEs. Prospectively collected short-term outcome data were analysed retrospectively. RESULTS: There was no difference in demographics, disease stage or tumour location between groups. IOTP rate and CRM positivity rates were similar between the two groups (p = .608). No difference was found in major (Clavien-Dindo III-V) complications, but we found statistically significant difference in minor (Clavien-Dindo I-II) complications (p = .01) in favour of the ELAPE group. Frequency of perineal SSI was lower in ELAPE group, but the difference was not significant (p = .320). Intraoperative iatrogenic complications occurred at significantly lower rate in ELAPE group (p = .035). Also, postoperative morbidity connected with the dissection in the perineal phase (e.g. urine incontinence, urinary retention) was significantly lower (p = .018) after ELAPE. DISCUSSION AND CONCLUSIONS: In our experience ELAPE operations may diminish the rate of Clavien-Dindo I-II complications compared to conventional APR. This effect is ensuing from the decrease of intraoperative iatrogenic complications and from the decrease of minor postoperative complications.

Extracellular vesicle release from intestinal organoids is modulated by Apc mutation and other colorectal cancer progression factors.

Extracellular vesicles (EVs) are membrane-surrounded structures that transmit biologically important molecules from the releasing to target cells, thus providing a novel intercellular communication mechanism. Since EVs carry their cargo in a protected form and their secretion is generally increased in tumorigenesis, EVs hold a great potential for early cancer diagnosis. By 3D culturing, we provide evidence that colorectal cancer (CRC) patient-derived organoids, representing a state-of-the-art established and essential approach for studying human CRC, is a suitable model for EV analysis. When testing the effects of major factors promoting CRC progression on EV release in the organoid model, we observed that Apc mutation, leading to uncontrolled Wnt activation and thus to tumorigenesis in the vast majority in CRC patients, critically induces EV release by activating the Wnt pathway. Furthermore, the extracellular matrix component collagen, known to accumulate in tumorigenesis, enhances EV secretion as well. Importantly, we show that fibroblast-derived EVs induce colony formation of CRC organoid cells under hypoxia. In contrast, there was no major effect of tumor cell-derived EVs on the activation of fibroblasts. Collectively, our results with CRC and Apc-mutant adenoma organoids identify Apc mutation and collagen deposition as critical factors for increasing EV release from tumors. Furthermore, we provide evidence that stromal fibroblast-derived EVs contribute to tumorigenesis under unfavorable conditions in CRC.

[Is preoperative systemic chemotherapy recommended for resectable colorectal liver metastases? Oncosurgical aspects]. / Reszekábilis colorectalis eredetu májáttét esetén javasolt-e a preoperatív szisztémás kezelés? Onkosebészeti nézopont.

Surgical resection is still the only curative treatment for colorectal liver metastases, but this is one part of a complex therapy. Nowadays a patient with colorectal liver metastasis is not treated only by a surgeon or by an oncologist or even only by an invasive radiologist. Collective decisions, complement treatments give the only chance to treat these patients for longer time. Patients with colorectal liver metastases could be regarded as patients with chronic disease. Specially interesting are the various treatment options of resectable colorectal liver metastases. The efficiency and necessity of preoperative chemotherapy are still a hot spot in the treatment of resectable liver metastases. In this study, we try to summarize the international and local experiences and the current evidence of the use of preoperative chemotherapy in the treatment of colorectal liver metastases. Orv Hetil. 2018; 159(21): 823-830.

[New perspectives in rectal cancer surgery: Transanal total mesorectal excision. Initial experiences]. / Új távlatok a végbélrák sebészetében: Transanalis teljes mesorectum excisio. Kezdeti eredményeink.

INTRODUCTION: Colorectal cancer is the second most frequent cause of oncologic mortality. Its key prognostic factors are operability and surgical quality. Total mesorectal excision is the gold standard of rectal cancer surgery, however, it is hardly achievable with the laparoscopic technique in a number of cases due to anatomical issues. Transanal total mesorectal excision (TaTME) is a new operative concept, which may address this technical problem. AIM: We aimed to present the initial Hungarian experiences with the new technique. METHOD: Retrospective analysis of clinical data of the first year case series at two Hungarian centers initiating the technique. RESULTS: A total of 17 transanal total mesorectal excision (TaTME) operations were performed at two centers. Major perioperative complications happened in two cases. There was no 30-day mortality. CONCLUSIONS: Early Hungarian experiences with transanal total mesorectal excision (TaTME) give hope of a brand new era of rectal cancer surgery. Orv Hetil. 2018; 159(1): 16-22.

[Advantages of transanal approach in low rectal cancer resections]. / A transanalis megközelítés elonye a mély rectumdaganatok mutéteinél.

Laparoscopic surgery is proven equal technique to open rectal surgery. Despite advantages, some problems in case of low rectal surgery are existing: visualization of the pelvis, securing safe distal resection margin, preparing single stapled rectal stump with safe conjunction to the colorectal anastomosis. Approximately 500 procedures have been performed worldwide until today by applying Transanal Total Mesorectal Excision (TaTME) technique, which evolved from a combination of laparoscopy and transanal approach. TaTME presents a solution to the low and mid-level rectal cases. The transanal path provides a better opportunity for preparing safe distal resection margin, an easier way for making a secure distal stump closure, and also offers perfect visualization even in the most difficult area, supporting the aim of nerve-sparing. We present a case, where we performed a synchronous laparoscopic and transanal TaTME resection of a down-sized low rectal tumor at 5 cm, after neoadjuvant radio-chemotherapy. To the best of our knowledge, this was the first case in Hungary, when TaTME was administered in a synchronous way.