RARRES2 regulates lipid metabolic reprogramming to mediate the development of brain metastasis in triple negative breast cancer.

BACKGROUND: Triple negative breast cancer (TNBC), the most aggressive subtype of breast cancer, is characterized by a high incidence of brain metastasis (BrM) and a poor prognosis. As the most lethal form of breast cancer, BrM remains a major clinical challenge due to its rising incidence and lack of effective treatment strategies. Recent evidence suggested a potential role of lipid metabolic reprogramming in breast cancer brain metastasis (BCBrM), but the underlying mechanisms are far from being fully elucidated. METHODS: Through analysis of BCBrM transcriptome data from mice and patients, and immunohistochemical validation on patient tissues, we identified and verified the specific down-regulation of retinoic acid receptor responder 2 (RARRES2), a multifunctional adipokine and chemokine, in BrM of TNBC. We investigated the effect of aberrant RARRES2 expression of BrM in both in vitro and in vivo studies. Key signaling pathway components were evaluated using multi-omics approaches. Lipidomics were performed to elucidate the regulation of lipid metabolic reprogramming of RARRES2. RESULTS: We found that down-regulation of RARRES2 is specifically associated with BCBrM, and that RARRES2 deficiency promoted BCBrM through lipid metabolic reprogramming. Mechanistically, reduced expression of RARRES2 in brain metastatic potential TNBC cells resulted in increased levels of glycerophospholipid and decreased levels of triacylglycerols by regulating phosphatase and tensin homologue (PTEN)-mammalian target of rapamycin (mTOR)-sterol regulatory element-binding protein 1 (SREBP1) signaling pathway to facilitate the survival of breast cancer cells in the unique brain microenvironment. CONCLUSIONS: Our work uncovers an essential role of RARRES2 in linking lipid metabolic reprogramming and the development of BrM. RARRES2-dependent metabolic functions may serve as potential biomarkers or therapeutic targets for BCBrM.

Expression dynamics of periodic transcripts during cancer cell cycle progression and their correlation with anticancer drug sensitivity.

BACKGROUND: The cell cycle is at the center of cellular activities and is orchestrated by complex regulatory mechanisms, among which transcriptional regulation is one of the most important components. Alternative splicing dramatically expands the regulatory network by producing transcript isoforms of genes to exquisitely control the cell cycle. However, the patterns of transcript isoform expression in the cell cycle are unclear. Therapies targeting cell cycle checkpoints are commonly used as anticancer therapies, but none of them have been designed or evaluated at the alternative splicing transcript level. The utility of these transcripts as markers of cell cycle-related drug sensitivity is still unknown, and studies on the expression patterns of cell cycle-targeting drug-related transcripts are also rare. METHODS: To explore alternative splicing patterns during cell cycle progression, we performed sequential transcriptomic assays following cell cycle synchronization in colon cancer HCT116 and breast cancer MDA-MB-231 cell lines, using flow cytometry and reference cell cycle transcripts to confirm the cell cycle phases of samples, and we developed a new algorithm to describe the periodic patterns of transcripts fluctuating during the cell cycle. Genomics of Drug Sensitivity in Cancer (GDSC) drug sensitivity datasets and Cancer Cell Line Encyclopedia (CCLE) transcript datasets were used to assess the correlation of genes and their transcript isoforms with drug sensitivity. We identified transcripts associated with typical drugs targeting cell cycle by determining correlation coefficients. Cytotoxicity assays were used to confirm the effect of ENST00000257904 against cyclin dependent kinase 4/6 (CDK4/6) inhibitors. Finally, alternative splicing transcripts associated with mitotic (M) phase arrest were analyzed using an RNA synthesis inhibition assay and transcriptome analysis. RESULTS: We established high-resolution transcriptome datasets of synchronized cell cycle samples from colon cancer HCT116 and breast cancer MDA-MB-231 cells. The results of the cell cycle assessment showed that 43,326, 41,578 and 29,244 transcripts were found to be periodically expressed in HeLa, HCT116 and MDA-MB-231 cells, respectively, among which 1280 transcripts showed this expression pattern in all three cancer cell lines. Drug sensitivity assessments showed that a large number of these transcripts displayed a higher correlation with drug sensitivity than their corresponding genes. Cell cycle-related drug screening showed that the level of the CDK4 transcript ENST00000547281 was more significantly associated with the resistance of cells to CDK4/6 inhibitors than the level of the CDK4 reference transcript ENST00000257904. The transcriptional inhibition assay following M phase arrest further confirmed the M-phase-specific expression of the splicing transcripts. Combined with the cell cycle-related drug screening, the results also showed that a set of periodic transcripts, for example, ENST00000314392 (a dolichyl-phosphate mannosyltransferase polypeptide 2 isoform transcript), was more associated with drug sensitivity than the levels of their corresponding gene transcripts. CONCLUSIONS: In summary, we identified a panel of cell cycle-related periodic transcripts and found that the levels of transcripts of drug target genes showed different values for predicting drug sensitivity, providing novel insights into alternative splicing-related drug development and evaluation.

Defueling the cancer: ATP synthase as an emerging target in cancer therapy.

Reprogramming of cellular metabolism is a hallmark of cancer. Mitochondrial ATP synthase (MAS) produces most of the ATP that drives the cell. High expression of the MAS-composing proteins is found during cancer and is linked to a poor prognosis in glioblastoma, ovarian cancer, prostate cancer, breast cancer, and clear cell renal cell carcinoma. Cell surface-expressed ATP synthase, translocated from mitochondrion to cell membrane, involves the angiogenesis, tumorigenesis, and metastasis of cancer. ATP synthase has therefore been considered a therapeutic target. We review recent various ATP synthase inhibitors that suppress tumor growth and are being tested for the clinic.

Biological effects of radiation on cancer cells.

With the development of radiotherapeutic oncology, computer technology and medical imaging technology, radiation therapy has made great progress. Research on the impact and the specific mechanism of radiation on tumors has become a central topic in cancer therapy. According to the traditional view, radiation can directly affect the structure of the DNA double helix, which in turn activates DNA damage sensors to induce apoptosis, necrosis, and aging or affects normal mitosis events and ultimately rewires various biological characteristics of neoplasm cells. In addition, irradiation damages subcellular structures, such as the cytoplasmic membrane, endoplasmic reticulum, ribosome, mitochondria, and lysosome of cancer cells to regulate various biological activities of tumor cells. Recent studies have shown that radiation can also change the tumor cell phenotype, immunogenicity and microenvironment, thereby globally altering the biological behavior of cancer cells. In this review, we focus on the effects of therapeutic radiation on the biological features of tumor cells to provide a theoretical basis for combinational therapy and inaugurate a new era in oncology.

Bifunctional fused polypeptide inhibits the growth and metastasis of breast cancer.

Breast cancer is the most common cancer and the leading cause of cancer-related death among women worldwide, with urgent need to develop new therapeutics. Targeted therapy is a promising strategy for breast cancer therapy. Stromal-derived factor-1/CXC chemokine receptor 4 (CXCR4) has been implicated in the metastasis of breast cancer, which renders it to be therapeutic target. This study aimed to evaluate the anticancer effect of fused TAT- DV1-BH3 polypeptide, an antagonist of CXCR4, and investigate the underlying mechanism for the cancer cell-killing effect in the treatment of breast cancer in vitro and in vivo. This results in a potent inhibitory effect of fused TAT-DV1-BH3 polypeptide on tumor growth and metastasis in nude mice bearing established MDA-MB-231 tumors. Fused TAT-DV1-BH3 polypeptide inhibited the proliferation of MDA-MB-231 and MCF-7 cells but did not affect that of HEK-293 cells. The fused TAT-DV1-BH3 polypeptide colocalized with mitochondria and exhibited a proapoptotic effect through the regulation of caspase-9 and -3. Furthermore, the fused TAT-DV1-BH3 polypeptide suppressed the migration and invasion of the highly metastatic breast cancer cell line MDA-MB-231 in a concentration-dependent manner. Notably, the DV1-mediated inhibition of the stromal-derived factor-1/CXCR4 pathway contributed to the antimetastasis effect, evident from the reduction in the level of phosphoinositide 3 kinase and matrix metalloproteinase 9 in MDA-MB-231 cells. Collectively, these results indicate that the apoptosis-inducing effect and migration- and invasion-suppressing effect explain the tumor regression and metastasis inhibition in vivo, with the involvement of caspase- and CXCR4-mediated signaling pathway. The data suggest that the fused TAT-DV1-BH3 polypeptide is a promising agent for the treatment of breast cancer, and more studies are warranted to fully elucidate the therapeutic targets and molecular mechanism.

A double-edged sword: CRISPR-Cas9 is emerging as a revolutionary technique for genome editing.

In May 2015, Professor Xiao Yang authored a review on the development of CRISPR-Cas9 techniques in the journal of Military Medical Research. This review provided a valuable overview of this major scientific advance. It has been four years since the first publication of the CRISPR-Cas9 breakthrough (Science. 2012; 337: 816-21). The use of this technique has expanded into various scientific areas and is being developed into a systematic technical platform that may contribute to many bioengineering fields involving DNA sequence editing.

Analysis on survival and prognostic factors for cancer patients with malignancy-associated hypercalcemia.

OBJECTIVE: To explore the incidence, clinical characteristics, diagnosis and treatment strategies, prognosis of patients with malignancy-associated hypercalcemia (MAH). METHODS: The data of 115 patients with MAH who were treated at the Medical Oncology Department of Chinese PLA General Hospital from Jan., 2001 to Dec., 2010 was retrospectively reviewed. Survival analysis was performed using the Kaplan-Meier method and the Cox proportional hazard model with statistic software SPSS 18.0. RESULTS: The patients had blood calcium levels ranging from 2.77 to 4.87 mmol/L. Except for 9 cases who died or were discharged within 5 days after admission, all other patients recovered to normal blood calcium level after treatment with bisphosphonates or intravenous hydration and diuretics; their survival after occurrence of MAH was from 1 day to 4,051 days, and the median survival time was only 50 days. In the log-rank test, the male, renal metastasis, central nervous system symptoms and hypercalcemia occurring over 140 days after cancer diagnosis were predictors of poor survival (P=0.002, P=0.046, P=0.000, P=0.009). In the COX analysis, being male, central nervous system symptoms and hypercalcemia lasting over 140 days after cancer diagnosis were independent prognostic factors for survival time (RR=2.131, P=0.027; RR=3.054, P=0.002; RR=2.403, P=0.001). According to these factors, a score system was established to predict the patient prognosis and adjust the treatment. CONCLUSION: Cancer patients with MAH have an extremely poor median survival. Some independent factors indicate poor prognosis, including male gender, central nervous system symptoms and hypercalcemia lasting over 140 days after cancer diagnosis. The prognostic score can serve as a reference for MAH prognosis and treatment, worthy of further investigation.

Expression and significance of ER, PR, VEGF, CA15-3, CA125 and CEA in judging the prognosis of breast cancer.

OBJECTIVE: To explore the expression and significance of estrogen receptor (ER), progestrone receptor (PR), vascular endothelial growth factor (VEGF), CA15-3, CA125 and carcinoma embryonic antigen (CEA) expression in judging the prognosis of breast cancer. MATERIALS AND METHODS: Sixty-five patients with breast cancer undergoing operations in the general surgery department were considered as the observation group, and 50 healthy outpatients of our hospital as the control group. Cubital venous blood was drawn in the morning from fasting patients in the two groups and chemiluminescence immunoassays were used to detect the levels of CA15-3, CA125 and CEA in serum. The follow-up duration was from 4 months to 2 years, and change in levels of the indicators was detected by dynamically drawing blood. After surgery, cancer tissue samples of patients in observation group remained on file (the non-recurrent patients were biopsied). Immunohistochemistry was applied to determine the expression of ER, PR and VEGF in tissue. RESULTS: The effective rate of 12 patients with negative ER and PR expression was 33.3% in the observation group, being associated with prognosis to varying extents. Serum CA15-3, CA125 and CEA in the observation group were all significantly higher than in control group (p<0.01). With increase in pathological staging, levels of serum CA15-3, CA125 and CEA gradually increased (p<0.01). Levels in patients with lymph node metastasis were markedly higher than in those without (p<0.01). In addition, values with distal lymph node metastasis were notably higher than with adjacent lymph node metastasis (p<0.01). The postoperative follow-up results revealed that positive VEGF and levels of serum VEGF, CA15-3, CA125 and CEA in recurrence group were obviously higher than in non-recurrence group (p<0.01). CONCLUSIONS: Joint detection of ER and PR expression as well as levels of serum VEGF, CA15-3, CA125 and CEA is meaningful and can guide the diagnosis and treatment for breast cancer.

[Role of endoplasmic reticulum protein folding molecular chaperones in floxuridine-resistance choriocarcinoma JeG-3/FUDRA cell line].

OBJECTIVE: To investigate changes of protein expression profiles between human choriocarcinoma JeG-3 cell line and its floxuridine (FUDR)-resistant sub-line. METHODS: The differentially expressed proteins were identified by using two dimension difference gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) approaches. Gene ontology (GO) analysis and Pathway analysis were used to screen the candidate proteins. The levels of the proteins in chemo-resistant sub-lines were validated by western blot. Ribonucleic acid interference (RNAi) was used to knockdown the expression of calreticulin (CALR) and (or) protein disulfide-isomerase A3 (PDIA3) respectively. RESULTS: Forty-six proteins spots were found to be significantly different in spot intensity by statistical analysis between chemo-resistance sub-line and parent cell line, of which 31 proteins were identified by MALDI-TOF-MS. Comparing to the parent cell lines, three endoplasmic reticulum (ER) protein folding molecular chaperones: CALR, PDIA3 and 78 000 glucose-regulated protein (GRP78) screened out were increased significantly in floxuridine-resistant sub-line and were verified by western blot. The resistance index decreased by knockdown the CALR and/or PDIA3 expression in FUDR-resistant sub-line 76.3% (36.7 ± 2.0 vs. 8.7 ± 3.1, P < 0.05) and 51.4% (36.7 ± 2.0 vs. 17.8 ± 1.2, P < 0.05) respectively. CONCLUSION: These ER protein folding molecular chaperones, CALR, PDIA3 and GRP78, may involved in the mechanism of FUDR-resistance choriocarcinoma.

[Relationship between MTA1 expression and invasive and metastatic ability of cervical cancer cell].

OBJECTIVE: To investigate the relationship between metastasis-associated gene 1 (MTA1) expression and invasive and metastatic ability of cervical cancer cell. METHODS: Three kinds of plasmids pcDNA3 (control group), pcDNA3-MTA1 (MTA1 group) and pSilencer3.1-MTA1-siRNA (MTA1-siRNA group) were transfected into human cervical cancer cell line CaSki cells. Reverse transcription (RT)-PCR and western blot were used to detected MTA1 mRNA and protein expressions. The effects of MTA1 expression on CaSki cell growth and proliferation, cell migration, adhesion and invasion, and cell cycles were tested by methyl thiazolyl tetrazolium (MTT), clone formation experiment, wound-healing assay, transwell assay, adhesion assay and flow cytometry, respectively. In animal experiment, three groups of cells were inoculated to BALB/c nude mouse subcutaneously to observe tumor formation ability. RESULTS: Compared with control group, MTA1 mRNA and protein were significantly overexpressed in MTA1 group, while MTA1-siRNA group showed lower MTA1 expression. Compared with control group, MTA1 group showed significantly accelerated cell growth; while MTA1-siRNA group showed decreased cell growth since the second day (P < 0.05). Clone formation number in control, MTA1 and MTA1-siRNA group were 133 ± 6, 169 ± 10 and 57 ± 5, respectively. MTA1 group showed accelerated cell formation, while MTA1-siRNA group showed the reverse effect compared with that in control group (P < 0.05). At 24, 48 and 72 hours after wounding, the healing ability of MTA1-siRNA group significantly lagged behind that in the control group, while MTA1 group showed accelerated cell healing ability. The adhesion rate of control, MTA1 and MTA1-siRNA group were (69.3 ± 3.6)%, (80.4 ± 5.6)% and (39.2 ± 7.4)% separately at 90 minutes after cell seeding. In contrast with control group, MTA1 group promoted the adhesion of CaSki cell to matrigel matrix, while MTA1-siRNA group inhibited the adhesion process (P < 0.05). In the migration assay, the number of cells migrated to the bottom side of the membrane in control, MTA1 and MTA1-siRNA group were 153 ± 17, 247 ± 38 and 82 ± 10, respectively. The number of cells in the invasion assay were 231 ± 19, 354 ± 36 and 76 ± 7, respectively. Compared with the control group, MTA1 group significantly increased the migration and invasion ability, while MTA1-siRNA group showed lower cell migration and invasion ability (P < 0.05). In cell cycle experiment, no significant differences of cell proportions including G(1), S and G(2) stage were found among three groups (P > 0.05). In animal experiment, compared with control group, MTA1 group showed accelerated tumor formation and growth, while the MTA1-siRNA group showed the reverse effect (P < 0.05). CONCLUSIONS: MTA1 may play its roles to promote cervical cancer cell invasion, migration, adhesion, as well as cell growth and colony formation, while RNA interference against MTA1 may decrease the malignant phenotypes. This study shows that it will be an effective beginning to explore metastasis mechanisms and cancer gene therapy strategy targeting MTA1 in cervical cancer.

[Adenovirus-delivered tissue inhibitor of metalloproteinases-3 transfection increases the sensitivity of cervical cancer cells to cisplatin].

OBJECTIVE: To investigate the effects of adenovirus-delivered tissue inhibitor of metalloproteinases-3 ( Ad-TIMP-3) on sensitivity of cervical cancer cells to cisplatin and evaluate the potential application of this combined scheme in cervical cancer treatment. METHODS: Cells of cervical cancer CaSKi cell line were infected with Ad-TIMP-3 in vitro. Apoptotic effect, cell cycle changes and p53 protein expression were detected. After combined treatment of those cells with cisplatin, colony formation test was performed and cytotoxicity was detected by MTT. The growth curve and tumor growth inhibition in vivo were evaluated. RESULTS: The expressions of TIMP-3 mRNA and protein were significantly upregulated after transfection. As a result, massive apoptosis was induced and the cells were arrested at G2/M phase. Exogenous overexpression of TIMP-3 increased p53 protein level markedly in spite of the backgrounds of p53 gene in cells. Combined with cisplatin treatment, the cloning efficiency was decreased. A synergism was observed by isobolic method ( D < 1 ) in vitro and tumor growth was significantly inhibited in vivo. CONCLUSION: Ad-TIMP-3 is a powerful proapoptotic agent. It increases sensitivity of the cells to cisplatin and the Ad-TIMP-3 gene therapy in combination with cisplatin could be a promising alternative in cervical cancer treatment.

[Effects of adenovirus delivered tissue inhibitor of metalloproteinases transfection on biological behaviors of cervical cancer cell lines].

OBJECTIVE: To explore the effects of adenovirus delivered tissue inhibitor of metalloproteinases-3 (Ad-TIMP-3) on the biological behaviors of cervical cancer cell lines and to evaluate its potential application in cervical cancer gene therapy. METHODS: We transferred Ad-TIMP-3 into cervical cancer cells. The TIMP-3 mRNA expression was assessed by RT-PCR, and the TIMP-3 and p53 protein expressions were assessed with Western blot. The apoptotic changes of cells were illustrated with morphology and DAPI staining. The viability of cells was determined with MTT assay. The abilities of in vitro invasion and adhesion were evaluated by the invasion and adhesion assays respectively. RESULTS: After infection, the TIMP-3 mRNA and protein were significantly upregulated in a time-dependent manner. Overexpression of TIMP-3 markedly increased p53 protein level in spite of the backgrounds of p53 gene in cells. Ad-TIMP-3 infection induced massive apoptosis of cervical cancer cells with a marked bystander effect. The abilities of in vitro invasion and adhesion were inhibited significantly (P < 0.01). The cytotoxicity of Ad-TIMP-3 was significantly stronger than that of Ad-p53 (P < 0.05, P < 0.01). CONCLUSIONS: Ad-TIMP-3 infection has cytotoxic effects on cervical cancer cells and can inhibit the expressions of these malignant phenotypes. Ad-TIMP-3 may be a potentially useful agent for cervical cancer gene therapy.

[The feasibility and mechanism of recombinant adenovirus Ad - p 14 ARF in gene therapy of liver cancer].

OBJECTIVE: To explore the feasibility and mechanism of recombinant adenovirus Ad-pl4ARF in cancer gene therapy. METHODS: The proliferation of different liver cancer cells was assessed by morphology and trypan blue assay. Cell apoptosis was confirmed by detecting phosphatidylserine (PS) externalization with Annexin V/PI double staining. The expression of related proteins was analyzed by Western bloting. Nude mouse model bearing subcutaneous transplanted BEL7402 tumor was established to study the therapeutic ability of Ad-pl4ARF. RESULTS: Ad-pl4ARF suppressed cell growth and proliferation, and promoted cell apoptosis of cancer cell lines with different genetic background. Ad-pl4ARF inhibited growth of liver cancer cells ( HepG2, BEL7402) in a dose-dependent manner. Ad-pl4ARF lead to overexpression of Bax and p21, the downstream regulating genes of p53. In the experimental therapy on nude mice bearing subcutaneous transplanted BEL7402 tumor, Ad-pl4ARF suppressed tumor growth significantly. CONCLUSION: pl4ARF is a short gene and with powerful function, which are consistent with the requirements for tumor suppressor genes used in gene therapy. It may play an important role in gene therapy against malignancies in the future.