At the stage of carcinoma in situ, the basement membrane (BM) segregates tumor cells from the stroma. This barrier must be breached to allow dissemination of the tumor cells to adjacent tissues. ...Cancer cells can perforate the BM using proteolysis; however, whether stromal cells play a role in this process remains unknown. Here we show that an abundant stromal cell population, cancer-associated fibroblasts (CAFs), promote cancer cell invasion through the BM. CAFs facilitate the breaching of the BM in a matrix metalloproteinase-independent manner. Instead, CAFs pull, stretch, and soften the BM leading to the formation of gaps through which cancer cells can migrate. By exerting contractile forces, CAFs alter the organization and the physical properties of the BM, making it permissive for cancer cell invasion. Blocking the ability of stromal cells to exert mechanical forces on the BM could therefore represent a new therapeutic strategy against aggressive tumors.Stromal cells play various roles in tumor establishment and metastasis. Here the authors, using an ex-vivo model, show that cancer-associated fibroblasts facilitate colon cancer cells invasion in a matrix metalloproteinase-independent manner, likely by pulling and stretching the basement membrane to form gaps.
Abstract
During tumor progression, cancer-associated fibroblasts (CAFs) accumulate in tumors and produce an excessive extracellular matrix (ECM), forming a capsule that enwraps cancer cells. This ...capsule acts as a barrier that restricts tumor growth leading to the buildup of intratumoral pressure. Combining genetic and physical manipulations in vivo with microfabrication and force measurements in vitro, we found that the CAFs capsule is not a passive barrier but instead actively compresses cancer cells using actomyosin contractility. Abrogation of CAFs contractility in vivo leads to the dissipation of compressive forces and impairment of capsule formation. By mapping CAF force patterns in 3D, we show that compression is a CAF-intrinsic property independent of cancer cell growth. Supracellular coordination of CAFs is achieved through fibronectin cables that serve as scaffolds allowing force transmission. Cancer cells mechanosense CAF compression, resulting in an altered localization of the transcriptional regulator YAP and a decrease in proliferation. Our study unveils that the contractile capsule actively compresses cancer cells, modulates their mechanical signaling, and reorganizes tumor morphology.
Metastatic uveal melanoma is a deadly disease with no proven standard of care. Here we present a metastatic uveal melanoma patient with an exceptional high sensitivity to a PD-1 inhibitor associated ...with outlier CpG>TpG mutation burden, MBD4 germline deleterious mutation, and somatic MBD4 inactivation in the tumor. We identify additional tumors in The Cancer Genome Atlas (TCGA) cohorts with similar hypermutator profiles in patients carrying germline deleterious MBD4 mutations and somatic loss of heterozygosity. This MBD4-related hypermutator phenotype may explain unexpected responses to immune checkpoint inhibitors.
Patient-derived xenograft models are considered to represent the heterogeneity of human cancers and advanced preclinical models. Our consortium joins efforts to extensively develop and characterize a ...new collection of patient-derived colorectal cancer (CRC) models.
From the 85 unsupervised surgical colorectal samples collection, 54 tumors were successfully xenografted in immunodeficient mice and rats, representing 35 primary tumors, 5 peritoneal carcinoses and 14 metastases. Histologic and molecular characterization of patient tumors, first and late passages on mice includes the sequence of key genes involved in CRC (i.e., APC, KRAS, TP53), aCGH, and transcriptomic analysis.
This comprehensive characterization shows that our collection recapitulates the clinical situation about the histopathology and molecular diversity of CRC. Moreover, patient tumors and corresponding models are clustering together allowing comparison studies between clinical and preclinical data. Hence, we conducted pharmacologic monotherapy studies with standard of care for CRC (5-fluorouracil, oxaliplatin, irinotecan, and cetuximab). Through this extensive in vivo analysis, we have shown the loss of human stroma cells after engraftment, observed a metastatic phenotype in some models, and finally compared the molecular profile with the drug sensitivity of each tumor model. Through an experimental cetuximab phase II trial, we confirmed the key role of KRAS mutation in cetuximab resistance.
This new collection could bring benefit to evaluate novel targeted therapeutic strategies and to better understand the basis for sensitivity or resistance of tumors from individual patients.
Chemoradiotherapy (CRT) is the current standard of care for patients diagnosed with locally advanced anal squamous cell carcinoma (ASCC), but some patients develop local and/or distant relapse during ...follow-up. This study was designed to monitor human papillomavirus (HPV) circulating tumor DNA (ctDNA) levels during CRT in patients with ASCC.
We analyzed samples from patients with HPV16- or HPV18-positive locally advanced ASCC. Blood samples were collected before and after CRT. HPV16 or HPV18 ctDNA detection was performed by droplet digital-PCR.
HPV ctDNA was detected before CRT in 29 of 33 patients with stages II-III ASCC sensitivity: 88%; 95% confidence interval (CI), 72-95; ctDNA positivity rate was associated with tumor stage (64% and 100% in stages II and III, respectively;
= 0.008). Among ctDNA-positive patients at baseline, ctDNA levels were higher in N
than in N
tumors (median 85 copies/mL, range = 8-9,333 vs. 32 copies/mL, range = 3-1,350;
= 0.03). ctDNA detection at baseline had no significant prognostic impact. After CRT, three of 18 (17%) patients displayed residual detectable HPV ctDNA; ctDNA detection after CRT was strongly associated with shorter disease-free survival (
< 0.0001).
This is the first proof-of-concept study assessing the prognostic value of ctDNA after CRT in locally advanced ASCC. In most patients, HPV ctDNA can be detected before CRT and becomes undetectable during CRT. In this study, we show that residual ctDNA levels after CRT are associated with very poor outcome.
Circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) have been recently investigated in several cancer types, but their respective clinical significance remains to be determined. In our ...prospective study, we compared the detection rate and the prognostic value of these two circulating biomarkers in patients with metastatic uveal melanoma. GNAQ/GNA11 mutations were characterized in archived tumor tissue. Using a highly sensitive and mutation‐specific bidirectional pyrophosphorolysis‐activated polymerization (bi‐PAP) technique, GNAQ c.626A>T, GNAQ c.626A>C and GNA11 c.626A>T copy numbers were quantified in plasma from 12 mL of blood. CTCs were detected at the same time in 7.5 mL of blood by the CellSearch® technique. Patient characteristics and outcome were prospectively collected. CTCs (≥1) were detected in 12 of the 40 included patients (30%, range 1–20). Among the 26 patients with known detectable mutations, ctDNA was detected and quantified in 22 (84%, range 4–11,421 copies/mL). CTC count and ctDNA levels were associated with the presence of miliary hepatic metastasis (p = 0.004 and 0.03, respectively), with metastasis volume (p = 0.005 and 0.004) and with each other (p < 0.0001). CTC count and ctDNA levels were both strongly associated with progression‐free survival (p = 0.003 and 0.001) and overall survival (p = 0.0009 and <0.0001). In multivariate analyses, ctDNA appeared to be a better prognostic marker than CTC. In conclusion, ctDNA and CTC are correlated and both have poor prognostic significance. CTC detection can be performed in every patient but, in patients with detectable mutations, ctDNA was more frequently detected than CTC and has possibly more prognostic value.
What's new?
In some cancers, tumor cells and tumor DNA find their way into the bloodstream and circulate around the body. These circulating markers present the tantalizing possibility of an easily performed test for disease prognosis. In this study, the authors sought to detect circulating tumor cells and DNA from metastatic uveal melanoma. They found that the two were highly correlated with each other, but not necessarily of strong prognostic value. Circulating tumor DNA, they report, was more frequently detected, and in patients with known mutations, might prove more useful for prognosis.
Disruption of splicing patterns due to mutations of genes coding splicing factors in tumors represents a potential source of tumor neoantigens, which would be both public (shared between patients) ...and tumor-specific (not expressed in normal tissues). In this study, we show that mutations of the splicing factor
in uveal melanoma generate such immunogenic neoantigens. Memory CD8
T cells specific for these neoantigens are preferentially found in 20% of patients with uveal melanoma bearing
-mutated tumors. Single-cell analyses of neoepitope-specific T cells from the blood identified large clonal T-cell expansions, with distinct effector transcription patterns. Some of these expanded T-cell receptors are also present in the corresponding tumors. CD8
T-cell clones specific for the neoepitopes specifically recognize and kill
-mutated tumor cells, supporting the use of this new family of neoantigens as therapeutic targets. SIGNIFICANCE: Mutations of the splicing factor
in uveal melanoma generate shared neoantigens that are uniquely expressed by tumor cells, leading to recognition and killing by specific CD8 T cells. Mutations in splicing factors can be sources of new therapeutic strategies applicable to diverse tumors.
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TTLL3 and TTLL8 are tubulin glycine ligases catalyzing posttranslational glycylation of microtubules. We show here for the first time that these enzymes are required for robust formation of primary ...cilia. We further discover the existence of primary cilia in colon and demonstrate that TTLL3 is the only glycylase in this organ. As a consequence, colon epithelium shows a reduced number of primary cilia accompanied by an increased rate of cell division in TTLL3‐knockout mice. Strikingly, higher proliferation is compensated by faster tissue turnover in normal colon. In a mouse model for tumorigenesis, lack of TTLL3 strongly promotes tumor development. We further demonstrate that decreased levels of TTLL3 expression are linked to the development of human colorectal carcinomas. Thus, we have uncovered a novel role for tubulin glycylation in primary cilia maintenance, which controls cell proliferation of colon epithelial cells and plays an essential role in colon cancer development.
Synopsis
This study reports first evidence for tubulin glycylation to affect the establishment and maintenance of primary cilia. Functional abrogation of tubulin glycine ligases impacts cell proliferation and tumor onset.
Glycylation and glycylases are required for robust primary cilia formation in mammals.
Colon epithelial cells have primary cilia that depend on the glycylase TTLL3.
Absence of TTLL3 leads to increased cell proliferation in colon.
Lack of TTLL3 promotes colon carcinogenesis.
This study reports first evidence for tubulin glycylation to affect the establishment and maintenance of primary cilia. Functional abrogation of tubulin glycine ligases impacts cell proliferation and tumor onset.
Abstract This article reports on the clinical practice guidelines developed by a multidisciplinary group working on the indications and uses of the various available treatment options for relieving ...intestinal obstruction or its symptoms in patients with peritoneal carcinomatosis. These guidelines are based on a literature review and expert opinion. The recommended strategy involves a clinical and radiological evaluation, of which CT of the abdomen is a crucial component. The results, together with an analysis of the prognostic criteria, are used to determine whether surgery or stenting is the best option. In most patients, however, neither option is feasible, and the main emphasis, therefore, is on the role and administration of various symptomatic medications such as glucocorticoids, antiemetic agents, analgesics, and antisecretory agents (anticholinergic drugs, somatostatin analogues, and proton-pump inhibitors). Nasogastric tube feeding is no longer used routinely and should instead be discussed on a case-by-case basis. Recent studies have confirmed the efficacy of somatostatin analogues in relieving obstruction-related symptoms such as nausea, vomiting, and pain. However, the absence of a marketing license and the high cost of these drugs limit their use as the first-line treatment, except in highly selected patients (early recurrence). When these medications fail to alleviate the symptoms of obstruction, venting gastrostomy should be considered promptly. Rehydration is needed for virtually every patient. Parenteral nutrition and pain management should be adjusted according to the patient needs and guidelines.
Gene fusions provide access to new therapeutic opportunities for patients treated for a colorectal cancer (CRC). However, they do not excess 1% of patients. A better identification of patients in ...whom gene fusions are highly prevalent is a major issue in a therapeutic and medico-economics perspective. This study assesses the rates of gene fusions in CRC patients with MSI/RAS-BRAFWT in our routine practice detected with a commercially available NGS-based fusion panel. Among the 130 MSI CRC tumors, 43 (33%) were KRAS-NRAS-BRAFWT. A gene fusion was detected in 7 (25.9%) of the 27 MSI/RAS-BRAFWT samples, which had RNA suitable for analysis after quality control. These fusions involved mainly NTRK1/3 (n = 5), as well as ALK (n = 1) and BRAF (n = 1). In the present study, we confirm that patients with MSI/RAS-BRAFWT CRCs represent a subpopulation in which targetable gene fusions are overrepresented. Our results support the use of a two-step algorithm for molecular screening, in which metastatic CRC patients would have routine MSI and RAS/BRAF testing, and then only those with MSI/RAS-BRAFWT would be screened with dedicated NGS RNA panel for gene fusions.
•Gene fusions do not excess 1% of patients with colorectal cancer (CRC).•Gene fusions are overrepresented in patients with MSI/RAS-BRAFWT CRC.•Most of gene fusions provide access to new therapeutic opportunities.•Our results support the use of a two-step algorithm for molecular screening.
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