Increased Expression of ALDH1A1 in Prostate Cancer is Correlated With Tumor Aggressiveness: A Tissue Microarray Study of Iranian Patients

ALDEFLUOR activity, ALDH isoforms, and their clinical significance in cancers

High aldehyde dehydrogenase (ALDH) activity is a metabolic feature of adult stem cells and various cancer stem cells (CSCs). The ALDEFLUOR system is currently the most commonly used method for evaluating ALDH enzyme activity in viable cells. This system is applied extensively in the isolation of normal stem cells and CSCs from heterogeneous cell populations. For many years, ALDH1A1 has been considered the most important subtype among the 19 ALDH family members in determining ALDEFLUOR activity. However, in recent years, studies of many types of normal and tumour tissues have demonstrated that other ALDH subtypes can also significantly influence ALDEFLUOR activity. In this article, we briefly review the relationships between various members of the ALDH family and ALDEFLUOR activity. The clinical significance of these ALDH isoforms in different cancers and possible directions for future studies are also summarised.

The Prognosis-Predictive and Immunoregulatory Role of SUMOylation Related Genes: Potential Novel Targets in Prostate Cancer Treatment

SUMOylation is an important part of post-translational protein modifications and regulates thousands of proteins in a dynamic manner. The dysregulation of SUMOylation is detected in many cancers. However, the comprehensive role of SUMOylation in prostate cancer (PCa) remains unclear. Using 174 SUMOylation-related genes (SRGs) from the MigDSB database and the transcript data of PCa from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), we constructed a SUMOylation-related risk score and correlated it with prognosis, tumor mutation burden (TMB), tumor microenvironment (TME) infiltration, and response to chemotherapy and immunotherapy. Moreover, we validated two vital SRGs by RT-qPCR, western blotting, and immunohistochemistry. Two vital SRGs (DNMT3B and NUP210) were finally selected. The risk score based on these genes exhibited excellent predictive efficacy in predicting the biochemical recurrence (BCR) of PCa. A nomogram involving the risk score and T stage was established to further explore the clinical value of the risk score. We found the high-score group was correlated with worse prognosis, higher TMB, a more suppressive immune microenvironment, and a better response to Docetaxel but worse to PD-1/CTLA-4 blockade. Meanwhile, we validated the significantly higher expression level of NUP210 in PCa at mRNA and protein levels. This study elucidated the comprehensive role of SUMOylation-related genes in PCa. Importantly, we highlighted the role of an important SRG, NUP210, in PCa, which might be a promising target in PCa treatment. A better understanding of SUMOylation and utilizing the SUMOylation risk score could aid in precision medicine and improve the prognosis of PCa.

Single-cell and bulk RNA sequencing reveal cancer-associated fibroblast heterogeneity and a prognostic signature in prostate cancer

Cancer-associated fibroblasts (CAFs), the central players in the tumor microenvironment (TME), can promote tumor progression and metastasis via various functions. However, the properties of CAFs in prostate cancer (PCa) have not been fully assessed. Therefore, we aimed to examine the CAF characteristics in PCa and construct a CAF-derived signature to predict PCa prognosis. CAFs were identified using single-cell RNA sequencing (scRNA-seq) data from 3 studies. We performed the FindAllMarkers function to extract CAF marker genes and constructed a signature to predict the biochemical relapse-free survival (bRFS) of PCa in the Cancer Genome Atlas (TCGA) cohort. Subsequently, different algorithms were applied to reveal the differences of the TME, immune infiltration, treatment responses in the high- and low-risk groups. Additionally, the CAF heterogeneity was assessed in PCa, which were confirmed by the functional enrichment analysis, gene set enrichment analysis (GSEA), and AUCell method. The scRNA-seq analysis identified a CAF cluster with 783 cells and determined 183 CAF marker genes. Cell-cell communication revealed extensive interactions between fibroblasts and immune cells. A CAF-related prognostic model, containing 7 genes (ASPN, AEBP1, ALDH1A1, BGN, COL1A1, PAGE4 and RASD1), was developed to predict bRFS and validated by 4 independent bulk RNA-seq cohorts. Moreover, the high-risk group of the signature score connected with an immunosuppressive TME, such as a higher level of M2 macrophages and lower levels of plasma cells and CD8+ T cells, and a reduced reaction rate for immunotherapy compared with low-risk group. After re-clustering CAFs via unsupervised clustering, we revealed 3 biologically distinct CAF subsets, namely myofibroblast-like CAFs (myCAFs), immune and inflammatory CAFs (iCAFs) and antigen-presenting CAFs (apCAFs). In conclusion, the CAF-derived signature, the first of its kind, can effectively predict PCa prognosis and serve as an indicator for immunotherapy. Furthermore, our study identified 3 CAF subpopulations with distinct functions in PCa.

Aldehyde dehydrogenase in solid tumors and other diseases: Potential biomarkers and therapeutic targets

The family of aldehyde dehydrogenases (ALDHs) contains 19 isozymes and is involved in the oxidation of endogenous and exogenous aldehydes to carboxylic acids, which contributes to cellular and tissue homeostasis. ALDHs play essential parts in detoxification, biosynthesis, and antioxidants, which are of important value for cell proliferation, differentiation, and survival in normal body tissues. However, ALDHs are frequently dysregulated and associated with various diseases like Alzheimer's disease, Parkinson's disease, and especially solid tumors. Notably, the involvement of the ALDHs in tumor progression is responsible for the maintenance of the stem-cell-like phenotype, triggering rapid and aggressive clinical progressions. ALDHs have captured increasing attention as biomarkers for disease diagnosis and prognosis. Nevertheless, these require further longitudinal clinical studies in large populations for broad application. This review summarizes our current knowledge regarding ALDHs as potential biomarkers in tumors and several non-tumor diseases, as well as recent advances in our understanding of the functions and underlying molecular mechanisms of ALDHs in disease development. Finally, we discuss the therapeutic potential of ALDHs in diseases, especially in tumor therapy with an emphasis on their clinical implications.

Prostate cancer as a dedifferentiated organ: androgen receptor, cancer stem cells, and cancer stemness

Cancer progression is characterized and driven by gradual loss of a differentiated phenotype and gain of stem cell-like features. In prostate cancer (PCa), androgen receptor (AR) signaling is important for cancer growth, progression, and emergence of therapy resistance. Targeting the AR signaling axis has been, over the decades, the mainstay of PCa therapy. However, AR signaling at the transcription level is reduced in high-grade cancer relative to low-grade PCa and loss of AR expression promotes a stem cell-like phenotype, suggesting that emergence of resistance to AR-targeted therapy may be associated with loss of AR signaling and gain of stemness. In the present mini-review, we first discuss PCa from the perspective of an abnormal organ with increasingly deregulated differentiation, and discuss the role of AR signaling during PCa progression. We then focus on the relationship between prostate cancer stem cells (PCSCs) and AR signaling. We further elaborate on the current methods of using transcriptome-based stemness-enriched signature to evaluate the degree of oncogenic dedifferentiation (cancer stemness) in pan-cancer datasets, and present the clinical significance of scoring transcriptome-based stemness across the spectrum of PCa development. Our discussions highlight the importance to evaluate the dynamic changes in both stem cell-like features (stemness score) and AR signaling activity across the PCa spectrum.

Correlations of ALD, Keap-1, and FoxO4 expression with traditional tumor markers and clinicopathological characteristics in colorectal carcinoma

Aldolase A (A-2) (ALD), Kelch-like-ECH associated protein-1 (Keap-1), and Forkhead box O4 (FoxO4) are key regulatory proteins, which have been proven to be involved in tumor development. However, the clinicopathological significance of ALD, Keap-1, and FoxO4 expressions in colorectal (colon) carcinoma (CRC) is not clearly known. We sought to explore the clinicopathological significance of ALD, Keap-1, and FoxO4 in CRC to provide evidences for potential monitoring index of CRC. Cases of 199 CRC patients were analyzed retrospectively. Evaluation of ALD, cAMP response element-binding protein-2, cyclo-oxygenase 2, FoxO4, Keap-1, and p53 expressions in CRC patients was accomplished with immunohistochemical technique. The patients were divided into negative and positive groups in accordance with immunohistochemical result. We compared the clinicopathological characteristics of the patients in the 2 groups, coupled with analysis of the relationship between 6 aforesaid proteins and clinicopathological characteristics. Herein, we confirmed the association of tumor location with the expression of ALD, Keap-1, and FoxO4. Also, tumor differentiation was observed to associate significantly with the expression of Keap-1, FoxO4, and Cox-2. The data also revealed that there was a correlation between smoking and expression of ALD, Keap-1, FoxO4, p53, and Cox-2. Nevertheless, insignificant difference was observed when clinicopathological characteristics were compared with cAMP response element-binding protein-2 expression. These findings suggest that ALD, Keap-1, and FoxO4 reinvolved in CRC development, and thus may be considered as potential monitoring protein for CRC.

Stem Cells as Target for Prostate cancer Therapy: Opportunities and Challenges

Cancer stem cells (CSCs) and cells in a cancer stem cell-like (CSCL) state have proven to be responsible for tumor initiation, growth, and relapse in Prostate Cancer (PCa) and other cancers; therefore, new strategies are being developed to target such cellular populations. TLR3 activation-based immunotherapy using Polyinosinic:Polycytidylic acid (PIC) has been proposed to be used as a concomitant strategy to first-line treatment. This strategy is based on the induction of apoptosis and an inflammatory response in tumor cells. In combination with retinoids like 9cRA, this treatment can induce CSCs differentiation and apoptosis. A limitation in the use of this combination is the common decreased expression of TLR3 and its main positive regulator p53. observed in many patients suffering of different cancer types such as PCa. Importantly, human exposure to certain toxicants, such as iAs, not only has proven to enrich CSCs population in an in vitro model of human epithelial prostate cells, but additionally, it can also lead to a decreased p53, TLR3 and RA receptor (RARβ), expression/activation and thus hinder this treatment efficacy. Therefore, here we point out the relevance of evaluating the TLR3 and P53 status in PCa patients before starting an immunotherapy based on the use of PIC +9cRA to determine whether they will be responsive to treatment. Additionally, the use of strategies to overcome the lower TLR3, RARβ or p53 expression in PCa patients, like the inclusion of drugs that increase p53 expression, is encouraged, to potentiate the use of PIC+RA based immunotherapy in these patients.

ALDH1A1 in Cancers: Bidirectional Function, Drug Resistance, and Regulatory Mechanism

Aldehyde dehydrogenases 1 family member A1(ALDH1A1) gene codes a cytoplasmic enzyme and shows vital physiological and pathophysiological functions in many areas. ALDH1A1 plays important roles in various diseases, especially in cancers. We reviewed and summarized representative correlative studies and found that ALDH1A1 could induce cancers via the maintenance of cancer stem cell properties, modification of metabolism, promotion of DNA repair. ALDH1A1 expression is regulated by several epigenetic processes. ALDH1A1 also acted as a tumor suppressor in certain cancers. The detoxification of ALDH1A1 often causes chemotherapy failure. Currently, ALDH1A1-targeted therapy is widely used in cancer treatment, but the mechanism by which ALDH1A1 regulates cancer development is not fully understood. This review will provide insight into the status of ALDH1A1 research and new viewpoint for cancer therapy.

Involvement of Cancer Stem Cells in Chemoresistant Relapse of Epithelial Ovarian Cancer Identified by Transcriptome Analysis

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy. Despite the initial resection and chemotherapeutic treatment, relapse is common, which leads to poor survival rates in patients. A primary cause of recurrence is the persistence of ovarian cancer stem cells (OCSCs) with high tumorigenicity and chemoresistance. To achieve a better therapeutic response in EOC relapse, the mechanisms underlying acquired chemoresistance associated with relapse-initiating OCSCs need to be studied. Transcriptomes of both chemosensitive primary and chemoresistant relapse EOC samples were obtained from ICGC OV-AU dataset for differential expression analysis. The upregulated genes were further studied using KEGG and GO analysis. Significantly increased expression of eighteen CSC-related genes was found in chemoresistant relapse EOC groups. Upregulation of the expression in four hub genes including WNT3A, SMAD3, KLF4, and PAX6 was verified in chemoresistant relapse samples via immunohistochemistry staining, which confirmed the existence and enrichment of OCSCs in chemoresistant relapse EOC. KEGG and GO enrichment analysis in microarray expression datasets of isolated OCSCs indicated that quiescent state, increased ability of drug efflux, and enhanced response to DNA damage may have caused the chemoresistance in relapse EOC patients. These findings demonstrated a correlation between OCSCs and acquired chemoresistance and illustrated potential underlying mechanisms of OCSC-initiated relapse in EOC patients. Meanwhile, the differentially expressed genes in OCSCs may serve as novel preventive or therapeutic targets against EOC recurrence in the future.

Cancer Stem Cell Markers for Urinary Carcinoma

Cancer stem cell (CSC) refers to cancer cells with stem cell properties, that is, they have the ability of “self-renewal” and “differentiation.” Cancer stem cells exist in cancer cells and are the “culprit” of cancer recurrence and metastasis. It is difficult to be found because of its small amount, and it is difficult for anticancer drugs to produce effects on it. At present, the isolation and identification of cancer stem cells from many solid tumors are still quite difficult, mainly due to the lack of specific molecular markers of cancer stem cells. In this review, cancer stem cell surface markers and functional markers in urinary system were summarized. These markers can provide molecular targets for cancer therapy.

Cytoplasmic expression of DCLK1-S, a novel DCLK1 isoform, is associated with tumor aggressiveness and worse disease-specific survival in colorectal cancer

BACKGROUND: Isoform-specific function of doublecortin-like kinase 1 (DCLK1) has highlighted the key role of the DCLK1-S (short isoform) in the maintenance, progression, and invasion of the tumor. OBJECTIVE: This study was designed to produce an anti-DCLK1-S polyclonal antibody to evaluate DCLK1-S in human colorectal cancer (CRC) specifically. METHODS: The expression pattern and clinical significance of DCLK1-S were assessed in a well-defined tissue microarray (TMA) series of 348 CRC and 51 adjacent normal tissues during a follow-up period of 108 months. RESULTS: Expression of DCLK1-S was significantly higher in CRC samples compared to adjacent normal samples (P< 0.001). Cytoplasmic expression of DCLK1-S was significantly higher in the tumors at the advanced stage of cancer and with poorer differentiation (P< 0.001, P= 0.02). The patients with CRC whose tumors showed higher cytoplasmic expression of DCLK1-S had worse disease-specific survival (DSS) (log-rank test, P= 0.03) and 5-year DSS rates (P= 0.01). Additionally, an improved prognostic value was observed in the patients with CRC with high DCLK1-S expression vs. its moderate expression (HR: 2.70, 95% CI: 0.98–7.38; p= 0.04) by multivariate analysis. CONCLUSIONS: Our findings strongly supported that high cytoplasmic expression of DCLK1-S compared to its moderate expression could be considered an independent prognostic factor influencing DSS.

The Mangrove-Derived Diterpenoid Diaporthe B Inhibits the Stemness and Increases the Efficacy of Docetaxel in Prostate Cancer PC-3 Cells

The absolute configuration of diaporthe B, a pimarane diterpene isolated from the mangrove derived endophytic fungus Eutypella sp #3E, was determined by a single-crystal x-ray diffraction study. The present study aimed to investigate the effects of diaporthe B on docetaxel-resistant prostate cancer PC-3 cells. Results of our studies showed that docetaxel-resistant PC-3 cells had higher sphere-forming efficiency and an increase in adherence to collagen-coated culture plates. The protein levels of cancer stem cell (CSC)-related markers CD44, CD133, and ALDH1A1 were higher in the docetaxel-resistant PC-3 cells than in the parental cells. Treatment with diaporthe B dose-dependently inhibited the growth and induced apoptosis in the resistant cells. Moreover, diaporthe B treatment decreased the sphere-forming efficiency and the adherence to collagen-coated plates in docetaxel-resistant PC-3 cells. Diaporthe B also decreased the protein levels of CSC-related markers CD44, CD133, and ALDH1A1 in the resistant cells. In addition, a combination of diaporthe B and docetaxel had a more potent effect on growth inhibition and apoptosis in the resistant cells than either agent alone. Our studies suggest that diaporthe B inhibits the stemness of prostate cancer cells and may have therapeutic potential for enhancing the efficacy of docetaxel in docetaxel-resistant prostate cancer cells.

The Multifaceted Role of Aldehyde Dehydrogenases in Prostate Cancer Stem Cells

Cancer stem cells (CSCs) are the only tumor cells possessing self-renewal and differentiation properties, making them an engine of tumor progression and a source of tumor regrowth after treatment. Conventional therapies eliminate most non-CSCs, while CSCs often remain radiation and drug resistant, leading to tumor relapse and metastases. Thus, targeting CSCs might be a powerful tool to overcome tumor resistance and increase the efficiency of current cancer treatment strategies. The identification and isolation of the CSC population based on its high aldehyde dehydrogenase activity (ALDH) is widely accepted for prostate cancer (PCa) and many other solid tumors. In PCa, several ALDH genes contribute to the ALDH activity, which can be measured in the enzymatic assay by converting 4, 4-difluoro-4-bora-3a, 4a-diaza-s-indacene (BODIPY) aminoacetaldehyde (BAAA) into the fluorescent product BODIPY-aminoacetate (BAA). Although each ALDH isoform plays an individual role in PCa biology, their mutual functional interplay also contributes to PCa progression. Thus, ALDH proteins are markers and functional regulators of CSC properties, representing an attractive target for cancer treatment. In this review, we discuss the current state of research regarding the role of individual ALDH isoforms in PCa development and progression, their possible therapeutic targeting, and provide an outlook for the future advances in this field.

Copper-64 Chloride Exhibits Therapeutic Potential in Three-Dimensional Cellular Models of Prostate Cancer

Prostate cancer (PCa) is the second most common cancer type in men, and in advanced metastatic stages is considerable incurable. This justifies the need for efficient early diagnostic methods and novel therapies, particularly radiopharmaceuticals with the potential for simultaneous diagnosis and therapy (theranostics). We have previously demonstrated, using monolayer-cultured cells, that copper-64 chloride, a promising theranostic agent for PCa, has the potential to induce significant damage in cancer cells while having minimal side effects in healthy tissues. Here, we further explored this compound for its theranostic applications using more advanced PCa cellular models, specifically multicellular spheroids. Namely, we evaluated the cellular uptake of ⁶⁴CuCl₂ in three human PCa spheroids (derived from 22RV1, DU145, and LNCaP cells), and characterized the growth profile and viability of those spheroids as well as the clonogenic capacity of spheroid-derived cells after exposure to ⁶⁴CuCl₂. Furthermore, the populations of cancer stem cells (CSCs), known to be important for cancer resistance and recurrence, present in the spheroid models were also evaluated using two different markers (CD44 and CD117). ⁶⁴CuCl₂ was found to have significant detrimental effects in spheroids and spheroid-derived cells, being able to reduce their growth and impair the viability and reproductive ability of spheroids from both castration-resistant (22RV1 and DU145) and hormone-naïve PCa (LNCaP). Interestingly, resistance to ⁶⁴CuCl₂ treatment seemed to be related with the presence of a CSC population, since the most resistant spheroids, derived from the DU145 cell line, had the highest initial percentage of CSCs among the three cell lines under study. Altogether, these results clearly highlight the theranostic potential of ⁶⁴CuCl₂.

Overexpression and translocation of dynamin 2 promotes tumor aggressiveness in breast carcinomas

Dynamin 2 is a GTPase protein that has been implicated in cancer progression through its various roles such as endocytosis, morphogenesis, epithelial-mesenchymal transition (EMT), cellular contractions, and focal adhesion maturation. The increased expression levels of this molecule have been demonstrated with the development of several cancers such as prostate, pancreas, and bladder. However, its clinical significance in breast cancer is unclear yet. In the present study, the membranous, cytoplasmic, and nuclear expression levels of dynamin 2 molecule were evaluated for the first time, using immunohistochemistry (IHC) on tissue microarray (TMA) slides in 113 invasive breast cancer tissues. Moreover, afterward, the association between the dynamin 2 expression and clinicopathological features was determined. Our finding showed that, a higher nuclear expression of dynamin 2 is significantly associated with an increase in tumor stage (P = 0.05), histological grade (P = 0.001), and age of the patients (P = 0.03). In addition, analysis of the cytoplasmic expression levels of this molecule revealed that, there was a statistically significant difference between the expression levels of dynamin 2 among the different breast cancer subtypes (P = 0.003). Moreover, a significant association was found between the increased expression of dynamin 2 membranous and vascular invasion (VI) (P = 0.02). We showed that dynamin 2 protein expression has an association with more aggressive tumor behavior and more advanced disease in the patients with breast cancer; therefore, dynamin 2 molecule could be considered as an indicator of disease progression and aggressiveness.

Low expression of Talin1 is associated with advanced pathological features in colorectal cancer patients

To explore the proper prognostic markers for the likelihood of metastasis in CRC patients. Seventy-seven fresh CRC samples were collected to evaluate the mRNA level of the selected marker using Real-time PCR. Moreover, 648 formalin-fixed paraffin-embedded CRC tissues were gathered to evaluate protein expression by immunohistochemistry (IHC) on tissue microarrays. The results of Real-Time PCR showed that low expression of Talin1 was significantly associated with advanced TNM stage (p = 0.034) as well as gender (p = 0.029) in mRNA levels. Similarly, IHC results indicated that a low level of cytoplasmic expression of Talin1 was significantly associated with advanced TNM stage (p = 0.028) as well as gender (p = 0.009) in CRC patients. Moreover, decreased expression of cytoplasmic Talin1 protein was found to be a significant predictor of worse disease-specific survival (DSS) (p = 0.011) in the univariate analysis. In addition, a significant difference was achieved (p = 0.039) in 5-year survival rates of DSS: 65% for low, 72% for moderate, and 88% for high Talin1 protein expression. Observations showed that lower expression of Talin1 at both the gene and protein level may drive the disparity of CRC patients’ outcomes via worse DSS and provide new insights into the development of progression indicators because of its correlation with increased tumor aggressiveness.

Association study between genetic variants in retinol metabolism pathway genes and prostate cancer risk

Background

Evidence suggests that serum retinol level is associated with prostate cancer risk, but the association between genetic variants in the retinol metabolism pathway genes and prostate cancer risk remains unclarified.

Methods

Single‐nucleotide polymorphisms (SNPs) in 31 genes in the retinol metabolism pathway were genotyped to evaluate the association with prostate cancer risk in 4,662 cases and 3,114 controls from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. The gene expression analysis was evaluated using data from the Gene Expression Omnibus (GEO) datasets and the Cancer Genome Atlas (TCGA) database. Data from the Genotype‐Tissue Expression (GTEx) project dataset were utilized to perform the expression quantitative trait loci (eQTL) analysis.

Results

Two SNPs were significantly associated with prostate cancer risk [rs1330286 in ALDH1A1: odds ratio (OR) = 0.88, 95% confidence interval (CI) = 0.83‐0.94, p = 2.45 × 10⁻⁴; rs4646653 in ALDH1A3: OR = 1.17, 95% CI =1.07‐1.27, p = 4.33 × 10⁻⁴]. Moreover, the mRNA level of ALDH1A3 was significantly higher in prostate cancer tissues than in normal tissues in both TCGA datasets and GEO datasets (p = 1.63 × 10⁻¹² and p = 4.33 × 10⁻², respectively). rs1330286 was an eQTL of ALDH1A1 (P = 2.90 × 10⁻³).

Conclusion

Our findings highlight that genetic variants in retinol metabolism pathway genes are associated with prostate cancer risk.

DCLK1, a promising colorectal cancer stem cell marker, regulates tumor progression and invasion through miR-137 and miR-15a dependent manner

Cancer stem cells (CSCs) are thought to be a major player in tumor initiation, progression, and metastasis. Targeting CSCs for elimination presents a promising therapeutic strategy; however, this approach will require a stronger understanding of CSC biology and identification of CSC-specific markers. The present study was conducted to examine the correlation between DCLK1 and miR-137 and miR-15a levels in colorectal cancer. A total of 222 samples, including 181 colorectal cancer specimens, 24 adenomatosis, and 17 non-adenomatosis colonic polyps, were stained for DCLK1 expression using immunohistochemistry. Also, expression of miR-137 and miR-15a was assessed in colorectal cancer with high and low DCLK1 expression levels. Most colorectal cancer specimens (76%) showed strong expression of DCLK1, whereas only 21% of adenomatous and none of non-adenomatous colonic polyps showed strong DCLK1 expression. A significant difference in DCLK1 expression was found between colorectal cancer, adenomatous, and non-adenomatous colonic polyps (P < 0.001). Higher expression of DCLK1 was more frequently detected in colorectal cases with larger tumor size (P = 0.03), poor differentiation (P = 0.03), and lymph node involvement (P = 0.04). Comparison of miR-137 and miR-15a in colorectal cancer cases revealed a significant inverse correlation with DCLK1 expression (P = 0.03 and P = 0.04, respectively). DCLK1 may act as a candidate marker for colorectal cancer stem cells. The critical role of DCLK1 in colorectal cancer suggests that it may represent an early diagnostic marker and therapeutic target; however, further investigation is warranted.

Advancements in Cancer Stem Cell Isolation and Characterization

Occurrence of stem cells (CSCs) in cancer is well established in last two decades. These rare cells share several properties including presence of common surface markers, stem cell markers, chemo- and radio- resistance and are highly metastatic in nature; thus, considered as valuable prognostic and therapeutic targets in cancer. However, the studies related to CSCs pave number of issues due to rare cell population and difficulties in their isolation ascribed to common stem cell marker. Various techniques including flow cytometry, laser micro-dissection, fluorescent nanodiamonds and microfluidics are used for the isolation of these rare cells. In this review, we have included the advance strategies adopted for the isolation of CSCs using above mentioned techniques. Furthermore, CSCs are primarily found in the core of the solid tumors and their microenvironment plays an important role in maintenance, self-renewal, division and tumor development. Therefore, in vivo tracking and model development become obligatory for functional studies of CSCs. Fluorescence and bioluminescence tagging has been widely used for transplantation assay and lineage tracking experiments to improve our understanding towards CSCs behaviour in their niche. Techniques such as Magnetic resonance imaging (MRI) and Positron emission tomography (PET) have proved useful for tracking of endogenous CSCs which could be helpful in their identification in clinical settings.

Cancer Stem-Like Cells in a Case of an Inflammatory Myofibroblastic Tumor of the Lung

Background: Inflammatory myofibroblast tumor (IMT) is a rare tumor with obscure etiopathogenesis in which different inflammatory cells and myofibroblastic spindle cells are seen histologically. Although the majority of these neoplasms have a benign clinical course, the malignant form has also been reported. The gold standard is surgical treatment for complete removal. Our report describes a 50-year-old woman who underwent surgery for IMT of the lung. The aim is to determine whether cancer stem cells may be present in IMT of the lung.

Methods: In April 2018, the patient underwent surgery for tumor mass asportation through lateral thoracotomy. The histology of the tumor was consistent with IMT of the lung. The ALDEFLUOR assay, after tissue digestion, was used to identify and sort human lung cancer cells expressing high and low aldehyde dehydrogenase (ALDH) activity. SOX2, NANOG, OCT-4, and c-MYC positivity were additionally determined by immunohistochemistry.

Results: The specimen contained 1.10% ALDH^high cells among all viable lung cancer cells, which indicates the population of cancer stem cells is not negligible. Immunohistochemically assessed cell positivity for ALDH1A1, SOX2, NANOG, OCT-4, and c-MYC, which are considered as lung cancer stem-like cells markers.

Conclusion: For the first time, we demonstrated the presence of cancer stem cells in a case of IMT of the lung. This finding may provide a base for considering new pathological and molecular aspects of this tumor. This perspective suggests further studies to understand the possibility of developing recurrence depending on the presence of cancer stem cells.

High GD2 expression defines breast cancer cells with enhanced invasiveness

INTRODUCTION

Breast cancer is the most frequently diagnosed cancer among women. Cancer stem cells (CSCs) are suggested to be responsible for tumor initiation, progression, metastasis, recurrence and drug resistance. This study was conducted to evaluate the clinical significance of GD2, a newly suggested CSC marker and two other traditional CSC markers, CD44 and CD24 in breast cancer patients.

MATERIAL AND METHODS

A total of 168 primary breast cancer tissues were evaluated in terms of GD2, CD44 and CD24 expression using tissue microarray. Then, the correlation of expression levels of these markers with patients' clinicopathological characteristics was assessed.

RESULTS

Higher GD2 expression was mainly found in patients with advanced histological grade (p = 0.02), presence of lymph node invasion (p = 0.04), larger size of tumors (p = 0.04) and older age (p = 0.04). Breast cancer samples with advanced histological grade also showed higher CD44 (p = 0.03) and CD24 expression (p = 0.05). A significant positive association was found between increased CD24 expression and lymph node involvement (p = 0.01). Furthermore, GD2-high/CD44-high/CD24-low phenotype was frequently seen in breast cancer samples with positive lymph node involvement (p = 0.05).

CONCLUSION

In summary, increased expression of GD2 may define more aggressive tumor behavior in breast cancer. GD2 can well be considered as a diagnostic and prognostic marker in breast cancer.

Increased expression of DCLK1, a novel putative CSC maker, is associated with tumor aggressiveness and worse disease-specific survival in patients with bladder carcinomas

Doublecortin-like kinase 1 (DCLK1) has been characterized as a novel potential cancer stem cell (CSC) marker in several types of cancer. It is considered as one of the most specific markers for distinguishing colorectal CSCs from normal stem cells. Yet, there are limited reports on the role of DCLK1 as a putative CSC marker in bladder cancer. Using immunohistochemistry, DCLK1 expression was examined in a well-defined tissue microarray series of 472 bladder cancer tissues. The association between DCLK1 protein expression and clinicopathological features, as well as survival outcomes, was assessed. Our findings showed strong, moderate, and weak DCLK1 expression in 123 (26.1%), 230 (48.7%), and 119 (25.2%) of the bladder cancer specimens, respectively. Higher expression of DCLK1 was significantly associated with increase in histological grade (P ≤ .001), pT stage (P = .014), lamina propria (P = .006), and lamina propria/muscularis (L/M) involvement (P = .014). On multivariate analysis, pT stage (P < .001), histological grade (P = .021), and lamina propria involvement (P = .001) were independent prognostic factors in DCLK1 expression. Moreover, the expression of DCLK1 was found to be an independent marker of poor prognosis for disease- specific survival (DSS) (P = .048) in bladder carcinomas. Our observations showed that DCLK1 expression was associated with more aggressive tumor behavior, more advanced disease, and poorer DSS in patients with bladder carcinomas. However, any potential clinical applications of DCLK1 as a novel target molecule in bladder cancer patients would require further investigations.

Association of homeobox B13 (HOXB13) gene variants with prostate cancer risk in an Iranian population

Background: Prostate cancer is a complex condition in which both genetic and environmental factors concomitantly contribute to the tumor initiation and progression. Recently, HOXB13 has been proposed as a susceptibility gene for prostate cancer.

Objective: The present study was conducted to determine the existence of potential variations in HOXB13 gene in Iranian men with prostate cancer (PCa) compared to benign prostatic hyperplasia (BPH) cases.

Methods: HOXB13 genetic status was screened in 51 samples, including 21 blood and tissue of PCa cases, and compared to 30 cases affected by BPH using PCR/sequencing. Then, the existence of potential association was investigated between genomic DNA alterations in blood and tissue PCa specimens.

Results: Analysis of BPH tissues showed single nucleotide variations c.366C > T (rs) or c.513T > C (rs9900627) in exon 1, but not in exon 2. Evaluation of PCa tissues revealed 2 cases with both synonymous c.366C > T and c.513T > C variants and 2 cases with the synonymous c.366C > T variant in exon 1. The variants c.366C > T and c.513T > C, simultaneously or separately, were found in blood samples of PCa patients. The novel variant c.127A > G in exon 2 was detected in 1 PCa blood sample. Our analysis indicated a significant reciprocal correlation between HOXB13 mutation in the tissue and blood samples of PCa cases (p= 0.02).

Conclusion: The variants in exon 2 of HOXB13 may influence the risk of prostate cancer. Also, evaluation of HOXB13 mutation may be considered as a novel marker for screening PCa. Further investigations are warranted to evaluate the clinical significance of HOXB13 in Iranian population.

Cancer stem cell research in Iran: potentials and challenges

Treatment modalities can reduce cancer-related mortality; however, a majority of patients develop drug resistance, metastasis and relapse. It has been proposed that tumorigenic characteristics of tumors are related to a proportion of cancer cells, termed cancer stem cells (CSCs). Following the first evidence regarding the existence of CSC population in acute myeloid leukemia in 1997, publications in CSCs field showed an explosive trend in all cancer types around the world. First research paper in the field of CSCs in Iran was published in 2004 on prostate cancer. Subsequently, an annual number of publications in the field of CSCs displayed a rapidly growing trend. Therefore, in the current review, we have presented a comprehensive evaluation of the CSCs research in Iran.

Prostate Tumor Overexpressed-1 (PTOV1) promotes docetaxel-resistance and survival of castration resistant prostate cancer cells

Metastatic prostate cancer is presently incurable. The oncogenic protein PTOV1, first described in prostate cancer, was reported as overexpressed and significantly correlated with poor survival in numerous tumors. Here, we investigated the role of PTOV1 in prostate cancer survival to docetaxel and self-renewal ability. Transduction of PTOV1 in docetaxel-sensitive Du145 and PC3 cells significantly increased cell survival after docetaxel exposure and induced docetaxel-resistance genes expression (ABCB1, CCNG2 and TUBB2B). In addition, PTOV1 induced prostatospheres formation and self-renewal genes expression (ALDH1A1, LIN28A, MYC and NANOG). In contrast, Du145 and PC3 cells knockdown for PTOV1 significantly accumulated in the G2/M phase, presented a concomitant increased subG1 peak, and cell death by apoptosis. These effects were enhanced in docetaxel-resistant cells. Analyses of tumor datasets show that PTOV1 expression significantly correlated with prostate tumor grade, drug resistance (CCNG2) and self-renewal (ALDH1A1, MYC) markers. These genes are concurrently overexpressed in most metastatic lesions. Metastases also show PTOV1 genomic amplification in significant co-occurrence with docetaxel-resistance and self-renewal genes. Our findings identify PTOV1 as a promoter of docetaxel-resistance and self-renewal characteristics for castration resistant prostate cancer. The concomitant increased expression of PTOV1, ALDH1A1 and CCNG2 in primary tumors, may predict metastasis and bad prognosis.

Clinical significance of endothelial cell marker CD34 and mast cell marker CD117 in prostate adenocarcinoma

Prostate cancer is the second cause of cancer-related deaths in men and this is attributed to its aggressiveness and metastatic identity. Our objective was to evaluate the expression patterns of endothelial cell marker CD34 and mast cell marker CD117 in prostate adenocarcinoma (PCa) compared to benign prostate tissue and their relation to the clinicopathological features. A total of 90 prostate samples, including 45 PCa and 45 benign prostate tissues were immunohistochemically examined for the detection of CD34 and CD117 markers. The expression of these markers was also correlated with clinicopathological parameters. Significant overexpression of CD34 was found in PCa group compared to benign prostate tissues (P≤0.001). The expression of CD34 and CD117 in PCa with advanced Gleason score was more than PCa with early Gleason score (P=0.02 and P=0.005, respectively). A significant positive correlation was observed between CD34 expression and the level of total serum prostate specific antigen (sPSA) (P=0.006). In addition, CD34High/CD117High phenotype was frequently observed in PCa cases compared to benign prostate tissues (P≤0.001). There was a positive significant association between CD34High/CD117High phenotype with advanced Gleason score (P≤0.001) and total sPSA level (P=0.02). Our findings showed that increased expression of CD34 and CD117 markers confer tumor progression and aggressiveness on PCa. These molecules may be good candidates for targeted therapy of PCa patients.

Co-Expression of Putative Cancer Stem Cell Markers CD44 and CD133 in Prostate Carcinomas

Cancer stem cells (CSCs) are the main players of prostate tumorigenesis thus; characterization of CSCs can pave the way for understanding the early detection, drug resistance, metastasis and relapse. The current study was conducted to evaluate the expression level and clinical significance of the potential CSC markers CD44 and CD133 in a series of prostate tissues. One hundred and forty eight prostate tissues composed of prostate cancer (PCa), high-grade prostatic intraepithelial neoplasia (HGPIN), and benign prostate hyperplasia (BPH) were immunostained for the putative CSC markers CD44 and CD133. Subsequently, the correlation between the expression of these markers and the clinicopathological variables was examined. A higher level of CD44 expression was observed in 42% of PCa, 57% of HGPIN, and 42% BPH tissues. In the case of CD133 expression PCa, HGPIN, and BPH samples demonstrated high immunoreactivity in 46%, 43%, and 42% of cells, respectively. Statistical analysis showed an inverse significant correlation between CD44 expression with Gleason score of PCa (P = 0.02), while no significant correlation was observed between CD133 expression and clinicopathological parameters. A significant reciprocal correlation was observed between the expression of two putative CSC markers CD44 and CD133 in PCa specimens while not indicating clinical significance. Further clinical investigation is required to consider these markers as targets of new therapeutic strategies for PCa.

Reduced expression of CXCR4, a novel renal cancer stem cell marker, is associated with high-grade renal cell carcinoma

PURPOSE

Cancer stem cells (CSCs) represent a population with tumour-initiating, self-renewal, and differentiation potential. This study aimed to evaluate the expression patterns and clinical significance of chemokine receptor type 4 (CXCR4) as a novel CSC marker in renal cell carcinoma (RCC).

METHODS

The expression of CXCR4 was examined in 173 well-defined renal tumour tissues, including 106 (61.5 %) clear cell renal cell carcinomas (ccRCCs), 35 (20 %) papillary renal cell carcinomas (pRCCs), and 32 (18.5 %) chromophobe renal cell carcinomas (ChRCCs), by immunohistochemistry on a tissue microarray. The association between expression of this marker and clinicopathologic parameters was then analysed.

RESULTS

There was a significant difference in the expression levels of CXCR4 in the ccRCC samples compared to the ChRCC and pRCC samples (P < 0.001). Increased expression of CXCR4 was significantly correlated with higher-grade tumours (P < 0.001) and worse stage (P = 0.001). A significant association was also found between expression of CXCR4 and microvascular invasion (P = 0.018). Among RCC subtypes, comparison of the differences between CXCR4 expression in low- and high-grade tumours demonstrated that pRCC tumours had a significantly higher expression of CXCR4 (P < 0.001) than ccRCC tumours (P = 0.01).

CONCLUSION

Significantly higher expression levels of CXCR4 were found in pRCC and ccRCC samples. Increased CXCR4 expression was associated with more aggressive tumour behaviour in RCC patients, especially in pRCC and ccRCC subtypes due to their more metastatic behaviour. These findings suggest that CXCR4 can be considered as a novel diagnostic and therapeutic marker for targeted therapy of renal carcinoma.