The potential role of miRNAs in the pathogenesis of salivary gland cancer - A Focus on signaling pathways interplay

Salivary gland cancer (SGC) is immensely heterogeneous, both in terms of its physical manifestation and its aggressiveness. Developing a novel diagnostic and prognostic detection method based on the noninvasive profiling of microribonucleic acids (miRs) could be a goal for the clinical management of these specific malignancies, sparing the patients' valuable time. miRs are promising candidates as prognostic biomarkers and therapeutic targets or factors that can advance the therapy of SGC due to their ability to posttranscriptionally regulate the expression of various genes involved in cell proliferation, differentiation, cell cycle, apoptosis, invasion, and angiogenesis. Depending on their biological function, many miRs may contribute to the development of SGC. Therefore, this article serves as an accelerated study guide for SGC and the biogenesis of miRs. Here, we shall list the miRs whose function in SGC pathogenesis has recently been determined with an emphasis on their potential applications as therapeutic targets. We will also offer a synopsis of the current state of knowledge about oncogenic and tumor suppressor miRs in relation to SGC.

Combinations of grape seed procyanidin extract and milk thistle silymarin extract against lung cancer - The role of MiR-663a and FHIT

AIMS

Grape seed procyanidin extract (GSE), and milk thistle silymarin extract (MTE) contain structurally distinct polyphenols, and each agent has been shown to exert antineoplastic effects against lung cancer. We hypothesize that combinations of GSE and MTE will additively enhance their anticancer effects against lung cancer.

MATERIALS AND METHODS

The anti-proliferative effects of GSE, MTE and combinations were evaluated in lung neoplastic cell lines. A dose range finding (DRF) study to determine safety, bioavailability and bioactivity, followed by human lung cancer xenograft efficacy studies were conducted in female nude mice with once daily gavage of leucoselect phytosome (LP), a standardized GSE, and/or siliphos, a standardized MTE. The roles of tumor suppressors miR-663a and its predicted target FHIT in mediating the additive, anti-proliferative effecs of GSE/MTE were also assessed.

KEY FINDINGS

GSE with MTE additively inhibited lung preneoplastic and cancer cell proliferations. Mice tolerated all dosing regimens in the DRF study without signs of clinical toxicity nor histologic abnormalities in the lungs, livers and kidneys. Eight weeks of LP and siliphos additively inhibited lung tumor xenograft growth. Plasma GSE/metabolites and MTE/metabolites showed that the combinations did not decrease systemic bioavailabilities of each agent. GSE and MTE additively upregulated miR-663a and FHIT in lung cancer cell lines; transfection of antisense-miR-663a significantly abrogated the anti-proliferative effects of GSE/MTE, upregulation of FHIT mRNA and protein. LP and siliphos also additively increased miR-663a and FHIT protein in lung tumor xenografts.

SIGNIFICANCE

Our findings support clinical translations of combinations of GSE and MTE against lung cancer.

MicroRNA mediated therapeutic effects of natural agents in prostate cancer

BACKGROUND

Several natural products, extensively studied for their anticancer activities, have been found to play an efficient role in preventing prostate cancer (PCa). Recently many natural agents have been reported to modulate microRNAs (miRNAs), that are involved in cancer cell growth. The microRNAs are endogenous small noncoding ribonucleic acid molecules that regulate various biological processes through an elegant mechanism of post-transcriptional control of gene expression. Besides being involved in cancer initiation, progression, angiogenesis, inflammation, they have been reported to be responsible for chemoresistance, and radioresistance of tumors. The dysregulated miRNA expression has been associated with many cancers including PCa. Over the past several years, it has been found that natural agents are good regulators of miRNAs and have a role in PCa also. Understanding the molecular mechanisms involving miRNAs by natural agents could result in developing useful strategies to combat this deadly disease.

METHODS

In order to collect research articles, the PubMed search engine was used with keywords 'prostate cancer' and 'natural agents' and 2007 papers were retrieved, further refinement with keywords 'phytochemical' and 'prostate cancer' showed 503 papers. Data was collected from research articles, published from 2010 to 2021. From these, research articles showing miRNA-mediated mechanisms were selected.

RESULTS

In this review, we have summarized the information available on the modulation of miRNAs by natural agents, their derivatives, and various combinatorial strategies with chemo/radiation therapy for the mitigation of PCa.

CONCLUSIONS

Based on the current review of literature, it has been found that the use of natural agents is a novel approach for altering miRNA expression strongly associated with PCa development, recurrence and resistance.

microRNA Levels in Cervical Cancer Samples and Relationship with Lesion Grade and HPV Infection

BACKGROUND

miR-21, miR-214, and miR-let-7a are three validated and well-known miRNAs. miR-21 is described as an "oncomir," while miR-214 and miR-let-7a are described mainly as tumor suppressors. The role of these miRNAs remains unclear in cervical cancer, an important malignancy among women worldwide and responsible for many deaths every year.

OBJECTIVE

The objective of this study was to describe the expression profile of miR-21, miR-214, and miR-let-7a in plasma and cervical scraping from a control group and patients with different grades of cervical lesions and invasive cervical cancer, and then correlate with HPV infection groups.

METHODS

Plasma and cervical scraping were submitted to DNA and RNA extraction. HPV detection and typing were performed by conventional PCR followed by PAGE to amplicons interpretation. The miRNA relative expression in plasma and cervical scraping samples was performed by real-time PCR using specific TaqMan probes.

RESULTS

miR-21 (p=0.0277) and miR-214 (p=0.0151) were up-regulated in cervical scraping samples of the invasive cervical cancer (ICC) group. However, miR-214 was also up-regulated in the LSIL group (p=0.0062). Both miRNAs were not related to HPV infection. However, miR-let-7a was higher in HPV positive plasma samples (p=0.0433) than in HPV negative plasma samples, and the correlation analysis confirmed the association between the levels of this miRNA with the presence of HPV (p=0.0407; r=0.3029), but not with lesion grade (p>0.05).

CONCLUSION

Our results suggest that miR-21 is related to cervical cancer progression and miR-214 appears to have an ambiguous role in cervical lesions. miR-let-7a may be upregulated at the systemic level in patients with HPV infection.

The Dual Regulatory Role of MiR-181a in Breast Cancer

MicroRNAs (miRNAs) are a family of highly conserved noncoding single-stranded RNA molecules of 21 to 25 nucleotides. miRNAs silence their cognate target genes at the post-transcriptional level and have been shown to have important roles in oncogenesis, invasion, and metastasis via epigenetic post-transcriptional gene regulation. Recent evidence indicates that the expression of miR-181a is altered in breast tumor tissue and in the serum of patients with breast cancer. However, there are several contradicting findings that challenge the biological significance of miR-181a in tumor development and metastasis. In fact, some studies have implicated miR-181a in regulating breast cancer gene expression. Here we summarize the current literature demonstrating established links between miR-181a and human breast cancer with a focus on recently identified mechanisms of action. This review also aims to explore the potential of miR-181a as a diagnostic and/or prognostic biomarker for breast cancer and to discuss the contradicting data regarding its targeting therapeutics and the associated challenges.

MicroRNA and Metastasis

Noncoding RNAs are important regulatory molecules of cellular processes. MicroRNAs (miRNAs) are small noncoding RNAs that bind to complementary sequences in the 3' untranslated region of target mRNAs, leading to degradation of the target mRNAs and/or inhibition of their translation. Some miRNAs are essential for normal animal development; however, many other miRNAs are dispensable for development but play a critical role in pathological conditions, including tumorigenesis and metastasis. miRNA genes often reside at fragile chromosome sites and are deregulated in cancer. Some miRNAs function as oncogenes or tumor suppressors, collectively termed "oncomirs." Specific metastasis-regulating miRNAs, collectively termed "metastamirs," govern molecular processes and pathways in malignant progression in either a tumor cell-autonomous or a cell-nonautonomous manner. Recently, exosome-transferred miRNAs have emerged as mediators of the tumor-stroma cross talk. In this chapter, we focus on the functions, mechanisms of action, and therapeutic potential of miRNAs, particularly oncomirs and metastamirs.