Oncoprotein HCCR-1 expression in breast cancer is well correlated with known breast cancer prognostic factors including the HER2 overexpression, p53 mutation, and ER/PR status

Mitochondrial matrix protein LETMD1 maintains thermogenic capacity of brown adipose tissue in male mice

Brown adipose tissue (BAT) has abundant mitochondria with the unique capability of generating heat via uncoupled respiration. Mitochondrial uncoupling protein 1 (UCP1) is activated in BAT during cold stress and dissipates mitochondrial proton motive force generated by the electron transport chain to generate heat. However, other mitochondrial factors required for brown adipocyte respiration and thermogenesis under cold stress are largely unknown. Here, we show LETM1 domain-containing protein 1 (LETMD1) is a BAT-enriched and cold-induced protein required for cold-stimulated respiration and thermogenesis of BAT. Proximity labeling studies reveal that LETMD1 is a mitochondrial matrix protein. Letmd1 knockout male mice display aberrant BAT mitochondria and fail to carry out adaptive thermogenesis under cold stress. Letmd1 knockout BAT is deficient in oxidative phosphorylation (OXPHOS) complex proteins and has impaired mitochondrial respiration. In addition, BAT-specific Letmd1 deficient mice exhibit phenotypes identical to those observed in Letmd1 knockout mice. Collectively, we demonstrate that the BAT-enriched mitochondrial matrix protein LETMD1 plays a tissue-autonomous role that is essential for BAT mitochondrial function and thermogenesis.

Deletion of Letmd1 leads to the disruption of mitochondrial function in brown adipose tissue

Human cervical cancer oncogene (HCCR-1), also named as LETMD1, is an LETM-domain containing outer mitochondrial membrane protein which plays an important role in carcinogenesis. The present study found that the loss of Letmd1 in mice led to severe abnormities, such as brown adipose tissue (BAT) whitening, impaired thermogenesis of both BAT and beige fat, cold intolerance, diet-induced obesity, glucose intolerance and insulin resistance. Mechanically, the deletion of Letmd1 in BAT caused decreased level of both mitochondrial and intracellular Ca²⁺. The reduced intracellular Ca²⁺ could suppress the fission of mitochondria and ultimately lead to the disruption of BAT thermogenesis by regulating mitochondrial structures and functions. This study indicates that LETMD1 played a crucial role in BAT thermogenesis and energy homeostasis through regulating mitochondrial structures and functions, which provides a novel insight into therapeutic target exploration from oncogenes for metabolic disorders.

HGF induces oncoprotein HCCR-1 expression through the Wnt/β-catenin pathway in gastric cancer

OBJECTIVE

Human cervical cancer oncogene (HCCR)-1, previously identified in cervical cancer and its cell lines, has been reported to play an important role in tumor progression in several cancers as a suppressor of apoptosis. However, the role of HCCR-1 in the tumorigenesis of stomach cancer has not been identified. This study examined the role of HCCR-1 as a suppressor of apoptosis during tumorigenesis in gastric cancer, along with its possible regulatory pathway.

METHODS

We employed several techniques including western blotting, semiquantitative reverse transcription polymerase chain reaction, diphenyltetrazolium bromide assay, chromatin immunoprecipitation assay, fluorescence-activated cell sorting, and HCCR-1 knockdown with short hairpin RNA to elucidate the role of HCCR-1.

RESULTS

We observed that hepatocyte growth factor (HGF) upregulated HCCR-1 expression. In addition, the expression levels of β-catenin, T cell factor-1 (TCF1), and B-cell lymphoma 2 (bcl2) were increased, whereas that of tumor protein 53 (p53) was decreased following HGF treatment. HCCR-1 knockdown in NUGC-3 and MKN-28 cells decreased the expression of TCF1 and phosphorylated β-catenin and increased the binding activity on the binding site of the HCCR-1 promoter. This identifies the possible involvement of the Wnt/β-catenin pathway in HGF-induced HCCR-1 regulation. We also confirmed the role of HCCR-1 in HGF-induced anti-apoptotic activity. p53 protein expression was increased, whereas that of bcl2 was decreased with HGF treatment in HCCR-1 knockdown cells, while the apoptotic activity was increased.

CONCLUSION

Our study suggests the anti-apoptotic activity of HGF-induced HCCR-1 expression and that HGF may regulate HCCR-1 via TCF1/β-catenin in stomach cancer.

HCCR-1 is a Novel Prognostic Indicator for Gastric Cancer and Promotes Cell Proliferation

The role of the human cervical cancer oncogene (HCCR-1) in the development of various tumors has been elucidated; however, its expression and function in gastric cancer remains largely unknown. Accordingly, the expression of HCCR-1 and epidermal growth factor (EGF) were detected in paired gastric cancer tissues and cell lines by western blotting (WB) and immunohistochemistry (IHC). Furthermore, the correlations between HCCR-1 expression in 209 gastric cancer tissues and the clinicopathological features and disease prognosis were analyzed. A stable HCCR-1 overexpression cell line was established, and the influence of increased HCCR-1 expression on the growth of gastric cancer cells was observed in vivo and in vitro. The expression of HCCR-1 generally increased in gastric cancer tissues. Further, increased HCCR-1 expression in gastric cancer tissues was associated with tumor T stage and was an independent factor that influenced poor postoperative prognosis in gastric cancer patients. A positive correlation was also detected between the expression of EGF and HCCR-1 in a time- and dose-dependent manner. The overexpression of HCCR-1 might enhance the growth rate of gastric cancer cells in vitro, increase the number of colony forming units, and promote the growth, volume, and weight of subcutaneous tumors in nude mice. In conclusion, HCCR-1 is a gastric cancer oncogene, and its increased expression plays a critical role in the occurrence and development of gastric cancer. Hence, HCCR-1 could serve as a valuable marker for the postoperative prognostic assessment of gastric cancer patients.

Discrimination of different cancer types clustering Raman spectra by a super paramagnetic stochastic network approach

Based in high sensitivity and specificity reported recently in detection of the cancer, the technique of Raman spectroscopy is proposed to discriminate between breast cancer, leukemia and cervical cancer using blood serum samples from patients officially diagnosed. In order to classify Raman spectra, clustering method known as Super Paramagnetic Clustering based on statistical physics concepts with a stochastic approach was implemented. Comparing firstly average Raman spectra of the three cancers, some peaks that allowed differentiating one cancer from other were identified, however, other peaks allowed concluding that there are biochemical similarities among them. According to these spectra, the band associated with amide I (1654 cm-1) and one of two shoulders assigned to amide III (1230-1282 cm-1) allowed discriminating leukemia from breast and cervical cancer, whereas band 714 cm-1 (polysaccharides) achieves to differentiate cervical cancer from leukemia and breast cancer, and bulged region, 1040 - 1100 cm-1 (phenylalanine, phospholipid) discriminated breast cancer from leukemia and cervical cancer. Subsequently, Super Paramagnetic Clustering method was applied to Raman spectra to study similarity relationships between cancers based on the biochemical composition of serum samples. Finally, as a cross check method, the standard method to classify Raman spectra of breast cancer, leukemia and cervical cancer, known as principal components analysis, was used showing excellent agreement with results of Super Paramagnetic Clustering method. Preliminary results demonstrated that Raman spectroscopy and Super Paramagnetic Clustering method can be used to discriminate between breast cancer, leukemia and cervical cancer samples using blood serum samples.

Targeting HCCR expression resensitizes gastric cancer cells to chemotherapy via down-regulating the activation of STAT3

The human cervical cancer oncogene (HCCR) has been found to be overexpressed in a variety of human cancers. However, the level of expression of HCCR and its biological function in gastric cancer are largely unknown. In this study, we evaluated HCCR expression in several gastric cancer cell lines and in one normal gastric mucosal cell line. We established a 5-FU-resistant gastric cancer cell subline, and we evaluated its HCCR expression. HCCR expression levels were high in gastric cancer lines, and expression was significantly increased in the 5-FU-resistant cancer cell subline. HCCR expression affected cell growth by regulating apoptosis in the cancer cells, and it had a positive correlation with p-STAT3 expression. Western blot and luciferase reporter assays showed that the activation of STAT3 upregulated HCCR expression in a positive feedback loop model. In vivo and in vitro studies showed that HCCR plays an important role in the apoptosis induced by 5-FU. Our data demonstrate that HCCR is probably involved in apoptosis and cancer growth and that it functions as a p-STAT3 stimulator in a positive feedback loop model. In gastric cancer cells, HCCR confers a more aggressive phenotype and resistance to 5-FU-based chemotherapy.

The role of human cervical cancer oncogene in cancer progression

Human cervical cancer oncogene (HCCR) was identified by differential display RT-PCR by screened abnormally expressed genes in cervical human cancers. The overexpressed gene is not only identified in cervical tissues, but also in various human cancers as leukemia/lymphoma, breast, stomach, colon, liver, kidney and ovarian cancer. For its special sensitivities and specificities in human breast cancer and hepatocellular carcinoma, it is expected to be a new biomarker to replace or combine with the existing biomarkers in the diagnose. The HCCR manifests as a negative regulator of the p53 tumor suppressor gene, and its expression is regulated by the PI3K/Akt signaling pathway, modulated by TCF/β-catenin, it also participates in induction of the c-kit proto-oncogene, in activation of PKC and telomerase activities, but the accurate biochemical mechanisms of how HCCR contributes to the malignancies is still unknown. The aim of this review is to summarize the roles of HCCR in cancer progression and the molecular mechanisms involved.

Quantitative detection of the human cervical cancer oncogene for monitoring the minimal residual disease in acute leukemia

The human cervical cancer oncogene (HCCR) has been shown to be over-expressed in some solid tumors, and its function is involved in negative regulation of p53 tumor suppressor gene. However, the roles of HCCR in leukemia remain unclear. The present study is to investigate whether the expression levels of HCCR mRNA are associated with clinical prognosis in patients with acute leukemia (AL) and to explore the potential use as a biomarker for monitoring minimal residual disease (MRD) in AL. The mRNA levels of HCCR1 and HCCR2 were quantified by real-time reverse transcription polymerase chain reaction in bone marrow samples from 80 adult de novo AL patients and 20 normal healthy donors. The expressions of HCCR1 and HCCR2 were significantly higher in patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) than those in healthy donors (P < 0.01), but there was no significant difference between AML and ALL (P > 0.05). Besides white blood cell count, we did not find any significant correlation between HCCR expression and clinical characteristics, such as age, sex, CD34 antigen expression, and response to chemotherapy. HCCR was monitored in 12 cases during remission and/or relapse. Significant reductions of both HCCR1 and HCCR2 mRNA levels were observed in patients who had achieved complete remission after chemotherapy but not in patients with non-responsive. However, an increased HCCR expression was detected in these patients who relapsed. Our findings suggest that HCCR gene is over-expressed in AL patients and may be as a useful biomarker for monitoring MRD in AL.

Clinical implication of elevated human cervical cancer oncogene-1 expression in esophageal squamous cell carcinoma

The human cervical cancer oncogene 1 (HCCR-1), a novel human oncoprotein, has been shown to be upregulated in various human tumors and plays a critical role in tumorigenesis and tumor progression. Here, the authors investigated HCCR-1 level in esophageal squamous cell carcinoma (ESCC) tissues and assessed the correlation between HCCR-1 level and prognosis of the patients with ESCC. HCCR-1 levels were investigated by immunohistochemistry, in situ hybridization, real-time quantitative RT-PCR and Western blotting methods; Kaplan-Meier curve was used to evaluate the prognostic value of HCCR-1 level in patients with ESCC using log-rank test. HCCR-1 displayed high levels in ESCC tissues compared to squamous dysplasia tissues and normal esophageal epithelial tissues. No significant correlation was observed between the levels of HCCR-1 mRNA and protein and gender and age (all p>0.05) but obviously related to histological grade, clinical stage, and lymph node metastasis (all p<0.001). Moreover, the survival rate of the patients with low HCCR-1 levels was higher than that of the patients with high HCCR-1 levels (both p<0.05). These data demonstrate that HCCR-1 may be used as a novel predictor for the prognosis of the patients with ESCC.

Variation of ATM Gene Expression in Peripheral Blood Cells of Sporadic Breast Carcinomas in Iranian Patients

The ataxia telangiectasia mutated gene (ATM), candidate for breast cancer susceptibility gene, encode a 350-kDa protein belongs to the core components of DNA-damage response machinery. Female AT carriers have at least 5-fold increase risk for breast cancer. Reduction in ATM expression is shown in multiple studies in breast tissues. We aimed to perform a research to measure the ATM mRNA expression in peripheral blood cells in breast cancer patients. Peripheral blood sample from 40 newly diagnosed, histologically confirmed female breast cancer patients was collected before surgery. Total RNA was isolated from blood cells using the RNX-Plus solution and reverse transcribed into cDNA. Real-time PCR was performed using the 2(-ΔΔCT) method to calculate relative changes in gene expression by REST software. The Relative Quantitation (RQ) mean was 1.27 with the min. and max. equal to 0.20 and 3.34, respectively. Calculation of patient frequencies in different groups revealed that 17.5% had reduced expression lower than two fold decreases and 15% high expression more than two fold increases, but according to REST software there was no up-regulation or down-regulation compared to normal females. The findings of multiple studies consistent with this study indicate that the ATM gene may play an important role in breast cancer development and progression, and ATM expression is down-regulated in breast cancer tissues. Although, some of the results do not support a suppressor role for ATM in the development of sporadic breast cancer, 17.5% of our patients had under expression of ATM mRNA less than two fold relative to control.

Association of estrogen receptor α gene PvuII and XbaI polymorphisms with non-small cell lung cancer

Single nucleotide polymorphisms (SNPs) of the estrogen receptor (ER)-α have been found to be associated with various diseases at significantly different frequencies. However, whether any relationship exists between ER-α polymorphisms and lung cancer remains to be determined. In this study, 84 non-smoking, female, non-small cell lung cancer patients with various stages of disease and 234 cancer-free reference controls were enrolled to examine the association of ER-α polymorphisms in lung cancer. Two restriction SNP sites, PvuII and XbaI, in the first intron of the ER-α gene were genotyped by polymerase chain reaction-restriction fragment length polymorphism. The frequencies of the PvuII-XbaI haplotypes and genotypes in a Taiwanese population were revealed for the first time. Although the genotypic frequencies of two polymorphic sites of ER- α were in linkage disequilibrium for the lung cancer group (χ(2)=50.013, d.f.=4) and reference controls (χ(2)=60.797, d.f.=4); and 7 and 8 combined genotypes were present, respectively, the distribution and the major genotypes are different in the two groups (p<0.0001). The p-values for PvuII and XbaI genotypes were significantly different between the lung cancer and reference controls. The PP genotype presence was found to be significantly lower in the lung cancer group (P=0.005), whereas presence of the xx genotype was significantly higher (P=0.042). These findings suggested that the PP genotype had a lower risk of lung cancer; whereas the xx genotype had a higher risk. In comparison with other studies conducted in various populations, it is of note that the pX haplotype frequency of this study was higher than that of other studies, whereas the px haplotype was lower. Moreover, the Xx genotypic frequency of XbaI polymorphisms in the ER-α gene of the reference control group was found to be extremely high, whereas the xx genotypic frequency was extremely low. In conclusion, PvuII-XbaI polymorphisms of the ER-α gene were found to be associated with the risk, but not cancer severity, of non-small cell lung cancer in a Taiwanese population.

Silencing of the HCCR2 gene induces apoptosis and suppresses the aggressive phenotype of hepatocellular carcinoma cells in culture

BACKGROUND

The human cervical cancer oncogene HCCR-2 is overexpressed in various malignant tumors and cell lines, and might function as a negative regulator of the p53 tumor suppressor. Here, we used RNA interference strategies to evaluate the role of HCCR-2 in liver cancer, and to explore its potential therapeutic effect.

METHODS

Changes of HepG2 cells stably transfected by an HCCR-2 RNA interference vector were detected by real-time PCR, MTT staining, plate colony formation, flow cytometry, and cell migration experiments. Apoptosis-related protein Bcl-2 and Bax levels were measured by Western blot.

RESULTS

Our results showed that of the three siRNA-expressing vectors, siRNA-H3 had a suppressive effect on the expression of HCCR-2 mRNA, interfering with proliferation and migration of HCCR-2. Moreover, the apoptotic rate also increased, and cells transfected by siRNA-H3 were blocked in the G0/G1 stage. Plate colony formation experiments demonstrated that the single cell clone formation capacity of HepG2-H3 cells was clearly lower than that of HepG2 and HepG2-N cells. Western blot results indicated that the expression of Bcl-2 was inhibited, and the expression of Bax was increased.

CONCLUSIONS

In summary, RNAi targeting HCCR-2 could be an effective means for suppressing malignant features of hepatocellular carcinoma cells.