Highlight: BRCA1 and BRCA2 proteins in breast cancer

Kolaviron Ameliorates 7, 12-Dimethylbenzanthracene - Induced Mammary Damage in Female Wistar Rats

BACKGROUND

Kolaviron (KV) is a flavonoid rich portion obtained from Garcinia kola seeds with a number of reported pharmacological effects. However, its ameliorative effects on 7,12-Dimethylbenzanthracene (DMBA)-induced mammary damage has not been fully investigated, despite the reported use of the seeds in the treatment of inflammatory related disorders.

OBJECTIVE

To evaluate the ameliorative effects of KV on DMBA-induced mammary damage in female Wistar rats.

METHODS

Forty-nine (49) female Wistar rats were randomly assigned into seven groups of seven rats each. DMBA was administered orally to rats in five of the groups as a single dose of 80 mg/kg body wt while the remaining two groups received the vehicle. The rats were palpated weekly for 3 months to monitor tumor formation. After 3 months of DMBA administration, 1 ml of blood was collected to assay for estrogen receptor- α (ER-α) level. Thereafter, the vehicle (dimethyl sulfoxide) was daily administered to the negative control and positive control groups for the 14 days duration of the experiment while three groups were each given a daily oral dose of 50, 100 and 200 mg/kg body wt of KV for the duration of the experiment. The last DMBA-induced group received 10 mg/kg body wt of the standard drug tamoxifen twice in a week and the remaining DMBA-free group received 200 mg/kg body wt KV. Subsequently, the animals were humanly sacrificed and ER-α, sialic acids, sialidase, sialyltransferase levels were assay for in blood and mammary tissues followed by histopathological examinations.

RESULTS

Significantly higher levels of estrogen receptor-α (ER-α), formation of lobular neoplastic cells, epithelial hyperplasia, lymphocyte infiltration and increased sialylation were detected in DMBA-induced rats. Treatment with KV at 50, 100 and 200 mg/kg body weight resulted in a significant (p<0.05) decrease in ER-α level, significantly (p<0.05) lower free serum sialic acid (21.1%), total sialic acid level of the mammary tissue (21.57%), sialyltransferase activity (30.83%) as well as mRNA level of the sialyltransferase gene (ST3Gal1) were observed after KV interventions.

CONCLUSION

The findings suggest that KV could be further explored in targeting DMBA-induced mammary damage implicated in mammary carcinogenesis.

Precision medicine and actionable alterations in lung cancer: A single institution experience

OBJECTIVES

Oncology has become more reliant on new testing methods and a greater use of electronic medical records, which provide a plethora of information available to physicians and researchers. However, to take advantage of vital clinical and research data for precision medicine, we must initially make an effort to create an infrastructure for the collection, storage, and utilization of this information with uniquely designed disease-specific registries that could support the collection of a large number of patients.

MATERIALS AND METHODS

In this study, we perform an in-depth analysis of a series of lung adenocarcinoma patients (n = 415) with genomic and clinical data in a recently created thoracic patient registry.

RESULTS

Of the 415 patients with lung adenocarcinoma, 59% (n = 245) were female; the median age was 64 (range, 22-92) years with a median OS of 33.29 months (95% CI, 29.77-39.48). The most common actionable alterations were identified in EGFR (n = 177/415 [42.7%]), ALK (n = 28/377 [7.4%]), and BRAF V600E (n = 7/288 [2.4%]). There was also a discernible difference in survival for 222 patients, who had an actionable alteration, with a median OS of 39.8 months as compared to 193 wild-type patients with a median OS of 26.0 months (P<0.001). We identified an unprecedented number of actionable alterations [53.5% (222/415)], including distinct individual alteration rates, as compared with 15.0% and 22.3% in TCGA and GENIE respectively.

CONCLUSION

The use of patient registries, focused genomic panels and the appropriate use of clinical guidelines in community and academic settings may influence cohort selection for clinical trials and improve survival outcomes.

Ubiquitin-associated (UBA) domain in human Fas associated factor 1 inhibits tumor formation by promoting Hsp70 degradation

Human Fas associated factor 1 (hFAF1) is a pro-apoptotic scaffolding protein containing ubiquitin-associating (UBA), ubiquitin like 1 and 2 (UBL1, UBL2), and ubiquitin regulatory X (UBX) domains. hFAF1 interacts with polyubiquitinated proteins via its N-terminal UBA domain and with valosin containing protein (VCP) via its C-terminal UBX domain. Overexpression of hFAF1 or its N-terminal UBA domain significantly increases cell death by increasing the degradation of polyubiquitinated proteins. In this study, we investigated whether hFAF1, whose expression level is reduced in cervical cancer, plays a role in tumor formation. We found that HeLa cells overexpressing full-length hFAF1 or the hFAF1 UBA domain alone, significantly suppressed the anchorage independent tumor growth in soft agar colony formation, increased cell death, and activated JNK and caspase 3. Employing UBA-specific tandem immunoprecipitation, we identified moieties specifically interacting with UBA domain of hFAF1, and found that polyubiquitinated Hsp70s are recruited to UBA domain. We also demonstrated that hFAF1 overexpression promotes Hsp70 degradation via the proteasome. We further found that mutating the UBA domain (I41N), as well as knocking down hFAF1 with specific RNAi, abolishs its ability to increase the proteasomal degradation of Hsp70. These findings suggest that hFAF1 inhibits tumor formation by increasing the degradation of Hsp70 mediated via its UBA domain.

Increased chromosomal radiosensitivity in women carrying BRCA1/BRCA2 mutations assessed with the G2 assay

PURPOSE

Several in vitro studies suggest that BRCA1 and BRCA2 mutation carriers present increased sensitivity to ionizing radiation. Different assays for the assessment of deoxyribonucleic acid double-strand break repair capacity have been used, but results are rather inconsistent. Given the concerns about the possible risks of breast screening with mammography in mutation carrier women and the potentially damaging effects of radiotherapy, the purpose of this study was to further investigate the radiosensitivity of this population.

METHODS AND MATERIALS

The G2 chromosomal radiosensitivity assay was used to assess chromosomal breaks in lymphocyte cultures after exposure to 1 Gy. A group of familiar breast cancer patients carrying a mutation in the BRCA1 or BRCA2 gene (n = 15) and a group of healthy mutation carriers (n = 5) were investigated and compared with a reference group of healthy women carrying no mutation (n = 21).

RESULTS

BRCA1 and BRCA2 mutation carriers had a significantly higher number of mean chromatid breaks per cell (p = 0.006) and a higher maximum number of breaks (p = 0.0001) as compared with their matched controls. Both healthy carriers and carriers with a cancer history were more radiosensitive than controls (p = 0.002 and p = 0.025, respectively). Age was not associated with increased radiosensitivity (p = 0.868).

CONCLUSIONS

Our results indicate that BRCA1 and BRCA2 mutation carriers show enhanced radiosensitivity, presumably because of the involvement of the BRCA genes in deoxyribonucleic acid repair and cell cycle control mechanisms.

Genetics and prevention of pancreatic cancer

BACKGROUND

Pancreatic cancer is an aggressive disease with a poor prognosis. Hereditary factors have been reported in up to 10% of cases of pancreatic cancer. The clinical characteristics and genetic abnormalities have been identified for a proportion of this high-risk group, and the development of preventive strategies for these individuals is now a primary goal of cancer clinicians.

METHODS

A review of the current literature regarding the genetics, screening, and prevention of pancreatic cancer and its precursor lesions was undertaken.

RESULTS

Risk factors for pancreatic cancer include smoking, chronic pancreatitis, and a genetic predisposition. The role of diabetes or a diet high in fat or meat remains unclear. The genetic mutations that accompany pancreatic cancer appear to occur in a temporal sequence, beginning in the earliest of precursor lesions. These mutations are detectable in pancreatic juice and, in conjunction with imaging, form the basis of screening programs for high-risk individuals. Not all precursor lesions will undergo malignant transformation, and testing is currently limited in its ability to determine which lesions will undergo transformation.

CONCLUSIONS

Avoiding tobacco smoking and minimizing risk factors associated with chronic pancreatitis are recommended to reduce the risk of pancreatic cancer. Individuals with a high-risk genetic background require counseling, genetic testing if appropriate (BRCA2 mutation or p16INK4A inactivity) and secondary screening for pancreatic cancer in specialist centers. Risk stratification will improve as more genetic abnormalities causing pancreatic cancer are defined.

Gene function in early mouse embryonic stem cell differentiation

Background

Little is known about the genes that drive embryonic stem cell differentiation. However, such knowledge is necessary if we are to exploit the therapeutic potential of stem cells. To uncover the genetic determinants of mouse embryonic stem cell (mESC) differentiation, we have generated and analyzed 11-point time-series of DNA microarray data for three biologically equivalent but genetically distinct mESC lines (R1, J1, and V6.5) undergoing undirected differentiation into embryoid bodies (EBs) over a period of two weeks.

Results

We identified the initial 12 hour period as reflecting the early stages of mESC differentiation and studied probe sets showing consistent changes of gene expression in that period. Gene function analysis indicated significant up-regulation of genes related to regulation of transcription and mRNA splicing, and down-regulation of genes related to intracellular signaling. Phylogenetic analysis indicated that the genes showing the largest expression changes were more likely to have originated in metazoans. The probe sets with the most consistent gene changes in the three cell lines represented 24 down-regulated and 12 up-regulated genes, all with closely related human homologues. Whereas some of these genes are known to be involved in embryonic developmental processes (e.g. Klf4, Otx2, Smn1, Socs3, Tagln, Tdgf1), our analysis points to others (such as transcription factor Phf21a, extracellular matrix related Lama1 and Cyr61, or endoplasmic reticulum related Sc4mol and Scd2) that have not been previously related to mESC function. The majority of identified functions were related to transcriptional regulation, intracellular signaling, and cytoskeleton. Genes involved in other cellular functions important in ESC differentiation such as chromatin remodeling and transmembrane receptors were not observed in this set.

Conclusion

Our analysis profiles for the first time gene expression at a very early stage of mESC differentiation, and identifies a functional and phylogenetic signature for the genes involved. The data generated constitute a valuable resource for further studies. All DNA microarray data used in this study are available in the StemBase database of stem cell gene expression data [1] and in the NCBI's GEO database.

A new member of the MCM protein family encoded by the human MCM8 gene, located contrapodal to GCD10 at chromosome band 20p12.3-13

The MCM8 protein from HeLa cells, a new member of the MCM family, co-isolates through several steps with MCM6 and MCM7, and MCM8 co-immunoprecipitates with MCM4, MCM6 and MCM7, proteins reportedly forming a helicase complex involved in initiation of DNA replication. MCM8 mRNA is expressed in placenta, lung and liver, but is also significantly expressed in adult heart, a tissue with a low percentage of proliferating cells. The MCM8 gene, consisting of 19 exons, is located contrapodal to a gene, consisting of 11 exons, encoding a homolog of the yeast GCD10 gene product. The region between these two transcription units, comprising as few as 62 bp, is TATA-less and highly GC-rich, containing multiple CpG units. MCM8 expression is altered in certain forms of neoplasia. In a case of choriocarcinoma MCM8 mRNA is aberrant, leading to expression of a protein lacking 16 amino acids. In several cases of colon adenocarcinoma MCM8 expression is greatly reduced relative to matched non-cancerous tissue. The potential helicase domain of MCM8 is different from those of other MCM proteins in that it is more homologous to canonical ATP-binding domains of other known helicases. Results suggest that MCM8 may interact with other MCM proteins to alter the function of the replicative MCM protein complex.