Elucidating the link between collagen and pancreatic cancer: what's next?

Combining immunotherapy and radiation therapy in gastrointestinal cancers: A review

INTRODUCTION AND PURPOSE

With a significant global impact, treatment of gastrointestinal (GI) cancers still presents with challenges, despite current multimodality approaches in advanced stages. Clinical trials are expanding for checkpoint inhibition (ICI) combined with radiation therapy (RT). This review intends to offer a comprehensive image of the current data regarding the effectiveness of this association, and to reflect on possible directions to further optimize the results.

RESULTS

Several early phase studies demonstrated encouraging potential. However, translating preclinical outcomes to clinical settings proves challenging, especially in immunologically "cold" environments. GI cancers exhibit heterogeneity, requiring tailored approaches based on disease stage and patient characteristics. Current results, though promising, lack the power of evidence to influence the general practice.

CONCLUSIONS

Finding biomarkers for identifying or converting resistant cancers is essential for maximizing responses, moreover in this context strategic RT parameters need to be carefully considered. Our review emphasizes the significance of having a thorough grasp of how immunology, tumour biology, and treatment settings interact in order to propose novel research avenues and efficient GI cancer therapy.

Thymoquinone affects the gemcitabine sensitivity of pancreatic cancer by regulating collagen via hypoxia inducible factor-1α

Objective: To clarify the potential therapeutic effects of thymoquinone (TQ) on pancreatic cancer and its gemcitabine (GEM) sensitivity. Methods: The expression levels of hypoxia inducible factor-1α (HIF-1α), collagens (COL1A1, COL3A1, and COL5A1), and transforming growth factor-β1 (TGFβ1) in pancreatic cancer and para-carcinoma tissues were compared using immunohistochemical methods, and their relationships with TNM staging were analyzed. The effects of TQ on apoptosis, migration, invasion, and GEM sensitivity of pancreatic cancer cells were assessed using in vitro and in vivo experiments. Western blot and immunohistochemistry were used to detect the expression levels of HIF-1α, extracellular matrix (ECM) production pathway-related proteins, and TGFβ/Smad signaling pathway-related proteins. Results: The expression levels of HIF-1α, COL1A1, COL3A1, COL5A1, and TGFβ1 in pancreatic cancer tissues were significantly higher than those in para-carcinoma tissues and correlated with TNM staging (p < 0.05). TQ and GEM administration inhibited the migration and invasion of the human pancreatic cancer cell line PANC-1 and promoted the apoptosis of PANC-1 cells. The combination of TQ and GEM was more effective than GEM alone. Western blot analysis showed that the expression levels of HIF-1α, ECM production pathway-related proteins, and TGFβ/Smad signaling pathway-related proteins were significantly decreased when TQ was used to treat PANC-1 cells (p < 0.05), and the expression levels of these proteins in the TQ + GEM group were significantly more decreased than those in the GEM group. Overexpression or knockdown of HIF-1α in PANC-1 cells showed the same effects as those induced by TQ administration. In vivo experiments showed that in PANC-1 tumor-bearing mice, tumor volume and tumor weight in mice treated with GEM and TQ were significantly lower than those in control or GEM-treated mice, whereas cell apoptosis was significantly increased (p < 0.05). Western blot and immunohistochemistry results showed that the levels of HIF-1α, ECM production pathway-related proteins, and TGFβ/Smad signaling pathway-related proteins in the GEM + TQ treatment group were further decreased compared to the control group or the GEM treatment group (p < 0.05). Conclusion: In pancreatic cancer cells, TQ can promote apoptosis, inhibit migration, invasion, and metastasis, and enhance the sensitivity to GEM. The underlying mechanism may involve the regulation of ECM production through the TGFβ/Smad pathway, in which HIF-1α plays a key role.

Immunotherapy as a Therapeutic Strategy for Gastrointestinal Cancer-Current Treatment Options and Future Perspectives

Gastrointestinal (GI) cancer constitutes a highly lethal entity among malignancies in the last decades and is still a major challenge for cancer therapeutic options. Despite the current combinational treatment strategies, including chemotherapy, surgery, radiotherapy, and targeted therapies, the survival rates remain notably low for patients with advanced disease. A better knowledge of the molecular mechanisms that influence tumor progression and the development of optimal therapeutic strategies for GI malignancies are urgently needed. Currently, the development and the assessment of the efficacy of immunotherapeutic agents in GI cancer are in the spotlight of several clinical trials. Thus, several new modalities and combinational treatments with other anti-neoplastic agents have been identified and evaluated for their efficiency in cancer management, including immune checkpoint inhibitors, adoptive cell transfer, chimeric antigen receptor (CAR)-T cell therapy, cancer vaccines, and/or combinations thereof. Understanding the interrelation among the tumor microenvironment, cancer progression, and immune resistance is pivotal for the optimal therapeutic management of all gastrointestinal solid tumors. This review will shed light on the recent advances and future directions of immunotherapy for malignant tumors of the GI system.

MECOM permits pancreatic acinar cell dedifferentiation avoiding cell death under stress conditions

Maintenance of the pancreatic acinar cell phenotype suppresses tumor formation. Hence, repetitive acute or chronic pancreatitis, stress conditions in which the acinar cells dedifferentiate, predispose for cancer formation in the pancreas. Dedifferentiated acinar cells acquire a large panel of duct cell-specific markers. However, it remains unclear to what extent dedifferentiated acini differ from native duct cells and which genes are uniquely regulating acinar cell dedifferentiation. Moreover, most studies have been performed on mice since the availability of human cells is scarce. Here, we applied a non-genetic lineage tracing method of human pancreatic exocrine acinar and duct cells that allowed cell-type-specific gene expression profiling by RNA sequencing. Subsequent to this discovery analysis, one transcription factor that was unique for dedifferentiated acinar cells was functionally characterized. RNA sequencing analysis showed that human dedifferentiated acinar cells expressed genes in "Pathways of cancer" with a prominence of MECOM (EVI-1), a transcription factor that was not expressed by duct cells. During mouse embryonic development, pre-acinar cells also transiently expressed MECOM and in the adult mouse pancreas, MECOM was re-expressed when mice were subjected to acute and chronic pancreatitis, conditions in which acinar cells dedifferentiate. In human cells and in mice, MECOM expression correlated with and was directly regulated by SOX9. Mouse acinar cells that, by genetic manipulation, lose the ability to upregulate MECOM showed impaired cell adhesion, more prominent acinar cell death, and suppressed acinar cell dedifferentiation by limited ERK signaling. In conclusion, we transcriptionally profiled the two major human pancreatic exocrine cell types, acinar and duct cells, during experimental stress conditions. We provide insights that in dedifferentiated acinar cells, cancer pathways are upregulated in which MECOM is a critical regulator that suppresses acinar cell death by permitting cellular dedifferentiation.

Integrated Analysis of Microarray and RNA-Seq Data for the Identification of Hub Genes and Networks Involved in the Pancreatic Cancer

Pancreatic cancer (PaCa) is the seventh most fatal malignancy, with more than 90% mortality rate within the first year of diagnosis. Its treatment can be improved the identification of specific therapeutic targets and their relevant pathways. Therefore, the objective of this study is to identify cancer specific biomarkers, therapeutic targets, and their associated pathways involved in the PaCa progression. RNA-seq and microarray datasets were obtained from public repositories such as the European Bioinformatics Institute (EBI) and Gene Expression Omnibus (GEO) databases. Differential gene expression (DE) analysis of data was performed to identify significant differentially expressed genes (DEGs) in PaCa cells in comparison to the normal cells. Gene co-expression network analysis was performed to identify the modules co-expressed genes, which are strongly associated with PaCa and as well as the identification of hub genes in the modules. The key underlaying pathways were obtained from the enrichment analysis of hub genes and studied in the context of PaCa progression. The significant pathways, hub genes, and their expression profile were validated against The Cancer Genome Atlas (TCGA) data, and key biomarkers and therapeutic targets with hub genes were determined. Important hub genes identified included ITGA1, ITGA2, ITGB1, ITGB3, MET, LAMB1, VEGFA, PTK2, and TGFβ1. Enrichment analysis characterizes the involvement of hub genes in multiple pathways. Important ones that are determined are ECM–receptor interaction and focal adhesion pathways. The interaction of overexpressed surface proteins of these pathways with extracellular molecules initiates multiple signaling cascades including stress fiber and lamellipodia formation, PI3K-Akt, MAPK, JAK/STAT, and Wnt signaling pathways. Identified biomarkers may have a strong influence on the PaCa early stage development and progression. Further, analysis of these pathways and hub genes can help in the identification of putative therapeutic targets and development of effective therapies for PaCa.

Inference of phenotype-relevant transcriptional regulatory networks elucidates cancer type-specific regulatory mechanisms in a pan-cancer study

Reconstruction of transcriptional regulatory networks (TRNs) is a powerful approach to unravel the gene expression programs involved in healthy and disease states of a cell. However, these networks are usually reconstructed independent of the phenotypic (or clinical) properties of the samples. Therefore, they may confound regulatory mechanisms that are specifically related to a phenotypic property with more general mechanisms underlying the full complement of the analyzed samples. In this study, we develop a method called InPheRNo to identify "phenotype-relevant" TRNs. This method is based on a probabilistic graphical model that models the simultaneous effects of multiple transcription factors (TFs) on their target genes and the statistical relationship between the target genes' expression and the phenotype. Extensive comparison of InPheRNo with related approaches using primary tumor samples of 18 cancer types from The Cancer Genome Atlas reveals that InPheRNo can accurately reconstruct cancer type-relevant TRNs and identify cancer driver TFs. In addition, survival analysis reveals that the activity level of TFs with many target genes could distinguish patients with poor prognosis from those with better prognosis.

Emerging Kinase Therapeutic Targets in Pancreatic Ductal Adenocarcinoma and Pancreatic Cancer Desmoplasia

Kinase drug discovery represents an active area of therapeutic research, with previous pharmaceutical success improving patient outcomes across a wide variety of human diseases. In pancreatic ductal adenocarcinoma (PDAC), innovative pharmaceutical strategies such as kinase targeting have been unable to appreciably increase patient survival. This may be due, in part, to unchecked desmoplastic reactions to pancreatic tumors. Desmoplastic stroma enhances tumor development and progression while simultaneously restricting drug delivery to the tumor cells it protects. Emerging evidence indicates that many of the pathologic fibrotic processes directly or indirectly supporting desmoplasia may be driven by targetable protein tyrosine kinases such as Fyn-related kinase (FRK); B lymphoid kinase (BLK); hemopoietic cell kinase (HCK); ABL proto-oncogene 2 kinase (ABL2); discoidin domain receptor 1 kinase (DDR1); Lck/Yes-related novel kinase (LYN); ephrin receptor A8 kinase (EPHA8); FYN proto-oncogene kinase (FYN); lymphocyte cell-specific kinase (LCK); tec protein kinase (TEC). Herein, we review literature related to these kinases and posit signaling networks, mechanisms, and biochemical relationships by which this group may contribute to PDAC tumor growth and desmoplasia.

High-grade mesenchymal pancreatic ductal adenocarcinoma drives stromal deactivation through CSF-1

Pancreatic ductal adenocarcinoma (PDAC) is characterized by an abundance of stroma. Multiple molecular classification efforts have identified a mesenchymal tumor subtype that is consistently characterized by high-grade growth and poor clinical outcome. The relation between PDAC stroma and tumor subtypes is still unclear. Here, we aimed to identify how PDAC cells instruct the main cellular component of stroma, the pancreatic stellate cells (PSCs). We found in primary tissue that high-grade PDAC had reduced collagen deposition compared to low-grade PDAC. Xenografts and organotypic co-cultures established from mesenchymal-like PDAC cells featured reduced collagen and activated PSC content. Medium transfer experiments using a large set of PDAC cell lines revealed that mesenchymal-like PDAC cells consistently downregulated ACTA2 and COL1A1 expression in PSCs and reduced proliferation. We identified colony-stimulating factor 1 as the mesenchymal PDAC-derived ligand that deactivates PSCs, and inhibition of its receptor CSF1R was able to counteract this effect. In conclusion, high-grade PDAC features stroma that is low in collagen and activated PSC content, and targeting CSF1R offers direct options to maintain a tumor-restricting microenvironment.

A quantum dot-based fluorescence sensing platform for the efficient and sensitive monitoring of collagen self-assembly

An efficient and sensitive assay for monitoring collagen self-assembly is presented.

Clinical value of serum hyaluronan and propeptide of type III collagen in patients with pancreatic cancer

Hyaluronan (HA) and collagen are highly expressed in pancreatic cancer (PC) stroma. HA and collagen accumulation increase tumor interstitial fluid pressure, compromising blood flow and drug penetration. The aim of this biomarker study was to determine the clinical utility of serum HA and the propeptide of type III collagen (PRO-C3) in patients with PC. A cohort from the Danish BIOPAC study (NCT03311776) including patients with histologically confirmed pancreatic ductal adenocarcinoma (n = 809), ampullary carcinoma (n = 44), distal biliary tract cancer (n = 31), chronic pancreatitis (n = 15), intraductal papillary mucinous neoplasm (n = 41), duodenal adenoma (n = 7) and no cancer (n = 25). Healthy controls were available for serum HA (n = 141) and PRO-C3 (n = 8). The main outcome was overall survival (OS) of patients with PC in relation to pretreatment serum HA and PRO-C3 levels. Patients with PC had higher baseline serum HA and PRO-C3 than healthy subjects and patients with benign conditions. Pretreatment serum baseline HA and PRO-C3 in patients with PC were associated with poorer survival and PRO-C3 remained prognostic also after adjusting for age, performance status, stage, the presence of liver and peritoneum metastasis, and CA19-9. Detection of HA and PRO-C3 may be useful in differentiating between malignant and benign pancreatic conditions. Serum HA and PRO-C3 were prognostic for OS in patients with PC.

Low P4HA2 and high PRTN3 expression predicts poor survival in patients with pancreatic cancer

BACKGROUND

The tumor microenvironment in pancreatic cancer has a multifaceted role in disease development and progression. Prolyl 4-hydroxylase subunit alpha 2 (P4HA2) and proteinase 3 (PRTN3) are involved in the synthesis and degradation of collagen in the tumor microenvironment and have been identified as prognostic biomarker candidates for pancreatic cancer in our previous mass spectrometric study. This study aimed at validating prognostic performance of P4HA2 and PRTN3 in a larger cohort of patients.

METHODS

The expression of P4HA2 and PRTN3 was evaluated with tissue microarrays and immunohistochemistry in 140 patients with pancreatic cancer who underwent surgical resection. Kaplan-Meier and Cox proportional hazards regression modeling were used to explore the association of P4HA2 and PRTN3, either separately or combined, with clinicopathological factors and survival.

RESULTS

Most tumors were positive for P4HA2 (133/140, 95%), whereas 77 tumors (55%) were positive for PRTN3. Expression levels of P4HA2 and PRTN3 did not separately correlate with disease-free or overall survival, in either uni- or multivariable analysis. However, a low P4HA2 and high PRTN3 expression correlated with shorter disease-free survival (median 7.0 vs. 13.4 months, adjusted HR 3.24, 95% CI: 1.13-9.25, p = .028) and overall survival (median 8.5 vs. 25.8 months, adjusted HR 8.14, 95% CI: 3.41-19.44, p < .001).

CONCLUSION

Our data show that a low P4HA2 and high PRTN3 expression correlates with poor survival in patients with pancreatic cancer, indicating the involvement of collagen deposition in the restraint of the tumor. The tumoral expression of PRTN3 reinforces the therapeutic potential of PR1-targeting immunotherapy in pancreatic cancer.