Emerging Role of miR-345 and Its Effective Delivery as a Potential Therapeutic Candidate in Pancreatic Cancer and Other Cancers

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with high mortality, poor prognosis, and palliative treatments, due to the rapid upregulation of alternative compensatory pathways and desmoplastic reaction. miRNAs, small non-coding RNAs, have been recently identified as key players regulating cancer pathogenesis. Dysregulated miRNAs are associated with molecular pathways involved in tumor development, metastasis, and chemoresistance in PDAC, as well as other cancers. Targeted treatment strategies that alter miRNA levels in cancers have promising potential as therapeutic interventions. miRNA-345 (miR-345) plays a critical role in tumor suppression and is differentially expressed in various cancers, including pancreatic cancer (PC). The underlying mechanism(s) and delivery strategies of miR-345 have been investigated by us previously. Here, we summarize the potential therapeutic roles of miR-345 in different cancers, with emphasis on PDAC, for miRNA drug discovery, development, status, and implications. Further, we focus on miRNA nanodelivery system(s), based on different materials and nanoformulations, specifically for the delivery of miR-345.

Novel Pathological Predictive Factors for Extranodal Extension in Oral Squamous Cell Carcinoma: a Retrospective Cohort Study Based on Tumor Budding, Desmoplastic Reaction, and Tumor-infiltrating Lymphocytes

Background: Extranodal extension (ENE) is a poor prognostic factor for oral squamous cell carcinoma (OSCC). Identifying ENE by clinical and/or radiological examination is difficult, thereby leading to unnecessary neck dissections. Currently, no definitive predictors are available for ENE. Thus, we aimed to determine the histological predictors of ENE by routine histopathological examination using biopsy and surgically resected specimens.Methods: This retrospective study included 186 surgically resected OSCC and 83 matched biopsy specimens. Clinical features associated with the tumor microenvironment, including desmoplastic reaction (DR), tumor budding (TB), and tumor-infiltrating lymphocytes (TILs), were evaluated using hematoxylin and eosin-stained primary OSCC and neck dissection specimens. These histological features were divided into two groups: DR-immature (DR-I) and DR-mature (DR-M); TB-high (TB-H) and TB-low (TB-L); and TILs-low (TILs-L) and TILs-high (TILs-H). Clinical depth of invasion (cDOI) and pathological DOI (pDOI) were adapted for biopsies and resections, respectively; DOI was evaluated as DOI >10 mm and DOI ≤10 mm. The clinicopathological relationships between these histopathological features and ENE and the independent risk factors for ENE were analyzed. The histological predictors of ENE were evaluated.Results:The histological status of DR, TILs, and TB present in biopsy and resection specimens showed high accuracy with that of ENE. DR-I, TILs-L, and TB-H were significantly associated with lymph node metastasis, cDOI, and pDOI. Bivariate and multivariate analyses revealed that TB-H and pDOI >10 mm in resections were independent factors for the presence of ENE (ENE+). The combination of TB-H/pDOI >10 mm in resection specimens showed high specificity (91%) and accuracy (83%) regarding ENE+. Although there proved to be no independent factors in biopsies, DR-I and TILs-L were significantly associated with ENE+ (p<0.001). The combination of DR-I/TILs-L/cDOI >10 mm in biopsies exhibited high sensitivity and specificity with ENE+ (70% and 77%, respectively, p<0.001). These histological predictors could detect even minor ENE (<2 mm).Conclusions:The tumor microenvironment status in primary OSCC was significantly associated with that of ENE, and TB-H was an independent risk factor for ENE. The histological status of DR-I/TILs-L/cDOI >10 mm in biopsy specimens and TB-H/pDOI >10 mm in resection specimens is a useful predictor of ENE.

Direct and Indirect Effect of TGFβ on Treg Transendothelial Recruitment in HCC Tissue Microenvironment

The balance between anti-tumor and tumor-promoting immune cells, such as CD4+ Th1 and regulatory T cells (Tregs), respectively, is assumed to dictate the progression of hepatocellular carcinoma (HCC). The transforming growth factor beta (TGFβ) markedly shapes the HCC microenvironment, regulating the activation state of multiple leukocyte subsets and driving the differentiation of cancer associated fibroblasts (CAFs). The fibrotic (desmoplastic) reaction in HCC tissue strongly depends on CAFs activity. In this study, we attempted to assess the role of TGFβ on transendothelial migration of Th1-oriented and Treg-oriented CD4+ T cells via a direct or indirect, CAF-mediated mechanisms, respectively. We found that the blockage of TGFβ receptor I-dependent signaling in Tregs resulted in impaired transendothelial migration (TEM) of these cells. Interestingly, the secretome of TGFβ-treated CAFs inhibited the TEM of Tregs but not Th1 cells, in comparison to the secretome of untreated CAFs. In addition, we found a significant inverse correlation between alpha-SMA and FoxP3 (marker of Tregs) mRNA expression in a microarray analysis involving 78 HCCs, thus suggesting that TGFβ-activated stromal cells may counteract the trafficking of Tregs into the tumor. The apparent dual behavior of TGFβ as both pro- and anti-tumorigenic cytokines may add a further level of complexity to the mechanisms that regulate the interactions among cancerous, stromal, and immune cells within HCC, as well as other solid tumors, and contribute to better manipulation of the TGFβ signaling as a therapeutic target in HCC patients.

Roles of the Mesenchymal Stromal/Stem Cell Marker Meflin/Islr in Cancer Fibrosis

Fibroblasts synthesise the extracellular matrix (ECM) such as collagen and elastin, the excessive accumulation of which can lead to fibrosis and organ dysfunction under pathological conditions. Cancer-associated fibroblasts (CAFs) are major constituents of the tumour microenvironment (TME) that accompany the desmoplastic reaction responsible for anti-cancer treatment resistance. Thus, it is important to dissect the roles of CAFs in the TME to develop new therapeutic strategies for refractory cancers. Recent progress in the studies of CAF biology suggests that the functions of CAFs are complicated and that they are composed of functionally distinct populations, including cancer-promoting CAFs (pCAFs) and cancer-restraining CAFs (rCAFs). We recently identified a new cell surface marker for rCAFs in pancreatic and colon cancers, designated as Meflin (mesenchymal stromal cell- and fibroblast-expressing Linx paralogue)/Islr (immunoglobulin super family containing leucine-rich repeat). Based on the distribution of Meflin/Islr-positive cells, we also considered it a specific candidate marker for mesenchymal stroma/stem cells. Meflin/Islr-positive CAFs have been shown to suppress cancer progression by being involved in regulating collagen structures and BMP signalling in the TME. This review describes the function of Meflin/Islr in cancer fibrosis as well as in cardiac and lung fibrosis and its potential in the development of new cancer therapeutics.

PD-1/PD-L1 expression in pancreatic cancer and its implication in novel therapies

Pancreatic cancer is the seventh leading cause of death in developed countries and it still has a poor prognosis despite intense research in the last 20 years. Immunotherapy is a relatively new strategy in cancer treatment. The aim of immunotherapy is to block the immunosuppressive effect of tumoral cells. The PD1/PD-L1 axis has an important role in the inhibition of effector T cells and the development of regulatory T cells (Tregs). Blocking these checkpoints, and also inhibitory signals, leads to apoptosis of Tregs and increased immune response of effector T cells against tumoral antigens. Unfortunately, pancreatic cancer is generally considered to be a non-immunogenic tumor. Thus PD-1/PD-L1 inhibitors demonstrated poor results in pancreatic cancer, excepting some patients with MSI/dMMR (microsatellite instability/deficient mismatch repair). Furthermore, pancreatic cancer has a particular microenvironment with a strong desmoplastic reaction, increased interstitial fluid pressure, hypoxic conditions, and acidic extracellular pH, which promote tumorigenesis and progression of the tumor. Mismatch repair deficiency (dMMR) is correlated with a high level of mutation-associated neoantigens, most recognized by immune cells which could predict a favorable response to anti-PD-1/PD-L1 therapy. PD-1/PD-L1 molecules could be also found as soluble forms (sPD-1, sPD-L1). These molecules have a potential role in the prognosis and treatment of pancreatic cancer.

Cancer-Associated Fibroblast (CAF) Heterogeneity and Targeting Therapy of CAFs in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease that typically features a dramatic desmoplastic reaction, especially fibroblasts. The roles of cancer-associated fibroblasts (CAFs) in PDAC have received more attention in recent years. As increasing evidence suggests the heterogeneity of CAFs in PDAC, different CAF subtypes have been shown to support tumor growth, while others suppress cancer proliferation. Myofibrotic CAFs (myCAFs) show alpha-smooth muscle actin (α-SMA)high interleukin-6 (IL-6)low myofibroblastic features, are activated by direct contact with tumor cells, and are located in the periglandular region. Inflammatory CAFs (iCAFs) show α-SMAlow IL-6high inflammatory features, are activated by paracrine factors secreted from tumor cells, and are located away from cancer cells. Antigen-presenting CAFs (apCAFs) show major histocompatibility complex II (MHC II) family genes that are highly expressed. CAFs have also been gradually explored as diagnostic and prognostic markers in pancreatic cancer. Targeted therapy of CAFs in PDAC has gradually attracted attention. With the deepening of related studies, some meaningful positive and negative results have surfaced, and CAFs may be the key to unlocking the door to pancreatic cancer treatment. Our review summarizes recent advances in the heterogeneity, function, and markers of CAFs in pancreatic cancer, as well as research and treatment targeting CAFs in pancreatic cancer.

MGMT Immunohistochemical Expression in Colorectal Carcinoma and its Correlation with Tumor Progression

Introduction: There is an urgent need to identify predictive features and markers for colorectal carcinoma (CRC) progression and treatment. This study aimed to assess O6-methylguanine DNA methyltransferase (MGMT) expression in CRC and correlate with the clinico-pathological aspects of the tumor, also to evaluate the relationship between different histopathologic parameters and tumor progression. Material and Methods: The study was carried on 70 colectomy using formalin fixed paraffin embedded tumor tissue. Immunohistochemistry was used to detect MGMT expression, and clinico-pathologic aspects as well as Tumor budding, type of desmoplastic reaction, inflammatory lymphocytic milieu, pattern of invasive front and necrosis were assessed Then correlated with MGMT expression and tumor progression, using parametric and nonparametric statistical methods. Results: MGMT Loss of expression was detected in 42.9% of CRC cases. MGMT expression status was significantly correlated with tumor stage and metastatic status (p<0.05), while it was not correlated with other clinic-pathologic features, (p>0.05). Desmoplastic reaction (DR), tumor budding, stromal tumor infiltrating lymphocytes (TIL-S) and necrosis were correlated with tumor stage (p<0.05). DR correlated with tumor budding (p<0.05). Both types of TIL and Crohn’s-like lymphoid reaction (CLR) showed a mutual correlation (p<0.05). Conclusion: MGMT high expression and histopathologic parameters as DR, tumor budding, inflammatory lymphocytic milieu and necrosis could be correlated with CRC progression.