Molecular Insights on the Therapeutic Effect of Selected Flavonoids on Diabetic Neuropathy

One of the common clinical complications of diabetes is diabetic neuropathy affecting the nervous system. Painful diabetic neuropathy is widespread and highly prevalent. At least 50% of diabetes patients develop diabetic neuropathy eventually. The four main types of diabetic neuropathy are peripheral neuropathy, autonomic neuropathy, proximal neuropathy (diabetic polyradiculopathy), and mononeuropathy (Focal neuropathy). Glucose control remains the common therapy for diabetic neuropathy due to limited knowledge on early biomarkers that are expressed during nerve damage, thereby limiting the cure through pharmacotherapy. Glucose control dramatically reduces the onset of neuropathy in type 1 diabetes but proves less effective in type 2 diabetes. Therefore, the focus is on various herbal remedies for prevention and treatment. There is numerous research on the use of anticonvulsants and antidepressants for the management of pain in diabetic neuropathy. Extensive research is being done on natural products including the isolation of pure compounds like flavonoids from plants and their effect on diabetic neuropathy. This review focuses on the use of an important of flavonoids such as flavanols (e.g., quercetin, rutin, kaempferol, and isorhamnetin), flavanones (e.g., hesperidin, naringenin and c,lass eriodictyol), and flavones (e.g., apigenin, luteolin, tangeretin, chrysin, and diosmin) for the prevention and treatment of diabetic neuropathy. The mechanisms of action of flavonoids against diabetic neuropathy by their antioxidant, anti-inflammation, anti-glycation properties, etc. are also covered in this review article.

Targeting loss of heterozygosity for cancer-specific immunotherapy

Developing therapeutic agents with potent antitumor activity that spare normal tissues remains a significant challenge. Clonal loss of heterozygosity (LOH) is a widespread and irreversible genetic alteration that is exquisitely specific to cancer cells. We hypothesized that LOH events can be therapeutically targeted by "inverting" the loss of an allele in cancer cells into an activating signal. Here we describe a proof-of-concept approach utilizing engineered T cells approximating NOT-gate Boolean logic to target counterexpressed antigens resulting from LOH events in cancer. The NOT gate comprises a chimeric antigen receptor (CAR) targeting the allele of human leukocyte antigen (HLA) that is retained in the cancer cells and an inhibitory CAR (iCAR) targeting the HLA allele that is lost in the cancer cells. We demonstrate that engineered T cells incorporating such NOT-gate logic can be activated in a genetically predictable manner in vitro and in mice to kill relevant cancer cells. This therapeutic approach, termed NASCAR (Neoplasm-targeting Allele-Sensing CAR), could, in theory, be extended to LOH of other polymorphic genes that result in altered cell surface antigens in cancers.

Genome-wide CRISPR knockout screens identify ADAMTSL3 and PTEN genes as suppressors of HCC proliferation and metastasis, respectively

PURPOSE

It is important for hepatocellular carcinoma (HCC) treatment that the targets related to its progression are identified. Clustered regularly interspaced short palindromic repeat (CRISPR)-associated nuclease 9 (Cas9)-based genetic screening is a powerful tool for identifying genes with loss-of-function mutations that are critical for tumour growth and metastasis.

METHODS

We transduced the human SMMC7721 HCC cell line expressing Cas9 with a human genome-scale CRISPR-Cas9 knockout (GeCKO) lentiviral library A (hGeCKOa) of 65,383 single-guide RNAs (sgRNAs) targeting 19,050 human genes; we then subcutaneously transplanted the transduced cells into nude mice.

RESULTS

The transduced cells were found to proliferate and metastasize faster than the untransduced cells. Through next-generation sequencing, the genes potentially related to HCC proliferation and metastasis were identified. The sgRNAs targeting the ADAMTSL3 and PTEN genes appeared twice on the list of genes related to HCC proliferation and metastasis, respectively. Analysis based on the data mining of Oncomine revealed that the ADAMTSL3 and PTEN genes were expressed at lower levels in HCC cells than they were in normal liver cells, indicating their tumour-suppressive roles. Downregulation of ADAMTSL3 and PTEN displayed poor overall survival (OS) and predicted poor relapse-free survival (RFS), further supporting their tumour-suppressive roles. Moreover, knocking out either the ADAMTSL3 or PTEN genes promoted either the proliferation or metastasis of HCC cells, respectively.

CONCLUSIONS

Using both in vitro and in vivo approaches, we described the profound role of the ADAMTSL3 and PTEN genes. This study indicates novel candidate targets for use in HCC treatment and therapy.

ARID1B, a member of the human SWI/SNF chromatin remodeling complex, exhibits tumour-suppressor activities in pancreatic cancer cell lines

Background:

The human ATP-dependent SWItch/sucrose nonfermentable (SWI/SNF) complex functions as a primary chromatin remodeler during ontogeny, as well as in adult life. Several components of the complex have been suggested to function as important regulators of tumorigenesis in various cancers. In the current study, we have characterised a possible tumour suppressor role for the largest subunit of the complex, namely the AT-rich interaction domain 1B (ARID1B).

Methods:

We performed Azacytidine and Trichostatin A treatments, followed by bisulphite sequencing to determine the possible DNA methylation-induced transcription repression of the gene in pancreatic cancer (PaCa) cell lines. Functional characterisation of effect of ARID1B ectopic expression in MiaPaCa2 PaCa cell line, which harboured ARID1B homozygous deletion, was carried out. Finally, we evaluated ARID1B protein expression in pancreatic tumour samples using immunohistochemistry on a tissue microarray.

Results:

ARID1B was transcriptionally repressed due to promoter hypermethylation, and ectopic expression severely compromised the ability of MiaPaCa2 cells to form colonies in liquid culture and soft agar. In addition, ARID1B exhibited significantly reduced/loss of expression in PaCa tissue, especially in samples from advanced-stage tumours, when compared with normal pancreas.

Conclusion:

The results therefore suggest a possible tumour-suppressor function for ARID1B in PaCa, thus adding to the growing list of SWI/SNF components with a similar function. Given the urgent need to design efficient targeted therapies for PaCa, our study assumes significance.

Association of the C47T polymorphism in SOD2 with diabetes mellitus and diabetic microvascular complications: a meta-analysis

AIMS/HYPOTHESIS

A meta-analysis was performed to assess the association of C47T (rs4880) (also called Val16Ala) polymorphism in SOD2 gene with reduced risk of diabetes mellitus, including type 1 and type 2 diabetes, and diabetic microvascular complications (DMI) including diabetic nephropathy, diabetic retinopathy and diabetic polyneuropathy.

METHODS

A comprehensive search was conducted to identify all case-control or cohort design studies of the above-mentioned associations. The fixed or random effect pooled measure was selected on the basis of homogeneity test among studies. Heterogeneity among studies was evaluated using the I (2). Meta-regression and the 'leave one out' sensitive analysis of Patsopoulos et al. were used to explore potential sources of between-study heterogeneity. Publication bias was estimated using modified Egger's linear regression test as proposed by Harbord et al.

RESULTS

Seventeen articles were included. After excluding articles that deviated from Hardy-Weinberg equilibrium in cases and/or in controls, and were also the key contributors to between-study heterogeneity, the meta-analysis showed a significant association of the C allele with reduced risk of DMI in dominant (OR 0.788, 95% CI 0.680-0.914), recessive (OR 0.808, 95% CI 0.685-0.953) and codominant (OR 0.828, 95% CI 0.751-0.913) models. It also showed a significant association with reduced risk of diabetic nephropathy in the dominant model (OR 0.801, 95% CI 0.664-0.967), and reduced risk of diabetic retinopathy in the dominant (OR 0.601, 95% CI 0.423-0.855), recessive (OR 0.548, 95% CI 0.369-0.814) and codominant (OR 0.651, 95% CI 0.517-0.820) models.

CONCLUSIONS/INTERPRETATION

The meta-analysis suggested that C allele of C47T polymorphism in SOD2 gene has protective effects on risk of DMI, diabetic nephropathy and diabetic retinopathy. This risk needs to be confirmed by further studies.

Allelic loss of 6q25-27, the PARKIN tumor suppressor gene locus, in cervical carcinoma

Studies on loss of heterozygosity have been made for Parkin gene-specific microsatellite markers in malignancies like breast, ovary and lungs, and the results have shown a significant association. However, till date, there is no study with respect to Parkin gene-associated microsatellite markers in cervical cancer. The present study deals with the Parkin gene-associated microsatellite markers and the occurrence of its loss of heterozygosity in patients with human cervical cancer. DNA was isolated from the 105 cervical carcinoma samples and matched control specimens. Polymerase chain reaction was performed using primer specific for two intragenic markers D6S1599 and D6S305 present in Parkin introns 2 and 7, respectively, and one marker (D6S1008) at telomeric end and further electrophoresed on 8% denaturing polyacrylamide gel. Overall, 59 of 105 (56%) samples showed loss of heterozygosity in at least one locus in the region examined. The percentage of loss of heterozygosity for these markers ranged from 25% (D6S1008) to 48% (D6S305). Chi-square test was performed, and loss of heterozygosity was found significantly higher in both the intragenic markers (D6S1599 and D6S305) when compared with the locus at telomeric end (D6S1008) with P<0.05. These data argue that Parkin is a tumor suppressor gene whose inactivation may play an important role in the carcinoma of uterine cervix.

Identification and characterization of the human NOL7 gene promoter

NOL7 is a candidate tumor suppressor gene that localizes to 6p23, a chromosomal region frequently associated with loss of heterozygosity in a number of malignancies including cervical cancer (CC). Re-expression of NOL7 in CC cells suppresses in vivo tumor growth by 95% and alters the angiogenic phenotype by modulating the expression of VEGF and TSP1. Here, we describe the determination of two NOL7 transcriptional start sites (TSS), the cloning of its regulatory promoter region, and the identification of transcription factors that regulate its expression. Using 5' Rapid amplification of complementary DNA ends (RACE), two transcriptional start sites were identified. Deletion analysis determined that the essential elements required for the optimal promoter activity of NOL7 were 560 bp upstream of its translation start site. In silico analysis suggested that the promoter region contained potential binding sites for the SP1, c-Myc and RXRalpha transcription factors as well as an overall GC content of greater than 60%. Chromatin immunoprecipitation (ChIP) confirmed that SP1, c-Myc and RXRalpha bound to the NOL7 promoter region. Finally, we demonstrate that NOL7 expression was positively regulated by c-Myc and RXRalpha. These results demonstrate that the NOL7 promoter region possesses each of the key elements of a TATA-less promoter. In addition, the positive regulation of NOL7 by c-Myc and RXRalpha provides additional mechanistic insights into the potential role of NOL7 in CC and other malignancies.