Baicalein suppresses HER2-mediated malignant transformation of HER2-overexpressing ovarian cancer cells by downregulating HER2 gene expression.

The upregulation of the HER2 oncogene is associated with a variety of human cancers and is associated with poor prognosis. Baicalein is reported to have anti-tumor activity, but the molecular mechanism of this effect in HER2-positive cancer cells has not been studied. In this study, our data showed that baicalein can inhibit the proliferation and transformation potential of ovarian cancer cells overexpressing HER2. Baicalein treatment caused a dose-dependent inhibition of HER2 gene expression at the transcriptional level. Baicalein acted on ovarian cancer cells overexpressing HER2 to downregulate the PI3K/Akt signaling pathway downstream of HER2 and inhibit the expression or activity of downstream targets, such as VEGF and cyclin D1 and MMP2. Oral administration of baicalein supplemented with a pharmaceutical excipient significantly inhibited the growth of HER2-overexpressing ovarian SKOV-3 cancer xenografts in mice. These results suggest that downregulation of HER2 gene expression by baicalein at the transcriptional level contributes to inhibit the in vitro and in vivo proliferation and HER2-mediated malignant transformation of HER2-overexpressing ovarian cancer cells.

Baicalein Induces G2/M Cell Cycle Arrest Associated with ROS Generation and CHK2 Activation in Highly Invasive Human Ovarian Cancer Cells.

Ovarian cancer is a lethal gynecological cancer because drug resistance often results in treatment failure. The CHK2, a tumor suppressor, is considered to be an important molecular target in ovarian cancer due to its role in DNA repair. Dysfunctional CHK2 impairs DNA damage-induced checkpoints, reduces apoptosis, and confers resistance to chemotherapeutic drugs and radiation therapy in ovarian cancer cells. This provides a basis for finding new effective agents targeting CHK2 upregulation or activation to treat or prevent the progression of advanced ovarian cancer. Here, the results show that baicalein (5,6,7-trihydroxyflavone) treatment inhibits the growth of highly invasive ovarian cancer cells, and that baicalein-induced growth inhibition is mediated by the cell cycle arrest in the G2/M phase. Baicalein-induced G2/M phase arrest is associated with an increased reactive oxygen species (ROS) production, DNA damage, and CHK2 upregulation and activation. Thus, baicalein modulates the expression of DNA damage response proteins and G2/M phase regulatory molecules. Blockade of CHK2 activation by CHK2 inhibitors protects cells from baicalein-mediated G2/M cell cycle arrest. All the results suggest that baicalein has another novel growth inhibitory effect on highly invasive ovarian cancer cells, which is partly related to G2/M cell cycle arrest through the ROS-mediated DNA breakage damage and CHK2 activation. Collectively, our findings provide a molecular basis for the potential of baicalein as an adjuvant therapeutic agent in the treatment of metastatic ovarian cancer.

Dual down-regulation of EGFR and ErbB2 by berberine contributes to suppression of migration and invasion of human ovarian cancer cells.

The overexpression of EGFR and/or ErbB2 occurs frequently in ovarian cancers and is associated with poor prognosis. The purpose of this study was to examine the anticancer effects and molecular mechanisms of berberine on human ovarian cancer cells with different levels of EGFR and/or ErbB2. We found that berberine reduced the motility and invasiveness of ovarian cancer cells. Berberine depleted both EGFR and ErbB2 in ovarian cancer cells. Furthermore, berberine suppressed the activation of the EGFR and ErbB2 downstream targets cyclin D1, MMPs, and VEGF by down-regulating the EGFR-ErbB2/PI3K/Akt signaling pathway. The berberine-mediated inhibition of MMP-2 and MMP-9 activity could be rescued by co-treatment with EGF. Finally, we demonstrated that berberine induced ErbB2 depletion through ubiquitin-mediated proteasome degradation. In conclusion, the suppressive effects of berberine on the ovarian cancer cells that differ in the expression of EGFR and ErbB2 may be mediated by the dual depletion of EGFR and/or ErbB2.

Ganoderma tsugae suppresses the proliferation of endometrial carcinoma cells via Akt signaling pathway.

Ganoderma is one of the common medicinal mushrooms in traditional Chinese medicine. Previous researches have unveiled the multifaceted biological activity of Ganoderma extract. Ganoderma tsugae has been investigated the potential on curing prostate, colon, lung, epidermoid, breast and ovarian cancers, but not including endometrial cancer. Endometrial cancer is a gynecological malignant tumor with serious drug resistance problem in clinical cancer treatment. This study aimed to demonstrate the first study of Ganoderma on treating endometrial cancer. The Ganoderma tsugae ethanol extract (GTEE) could suppress the proliferation of endometrial cancer cells HEC-1-A, KLE, and AN3 CA. GTEE also induced G1/S phase arrest and mitochondria-mediated apoptosis in endometrial cancer cells. Furthermore, the Akt signaling pathway could be suppressed by GTEE. Therefore, our results suggest for the first time that GTEE has the potential to be an adjuvant therapeutic agent in the treatment of endometrial cancer.

Cytotoxic and Anti-inflammatory Terpenoids from the Whole Plant of Vaccinium emarginatum.

Two new Δ12 ursene-type triterpenoid coumaroyl esters (1: and 2: ), one new Δ7,15 isopimarane-type diterpenoid glycoside (20: ), and two new irido-δ-lactone-type iridoids (21: and 22: ), together with 17 known pentacyclic triterpenoids (3:  - 19: ), were isolated during the phytochemical investigation of a methanol extract of the whole plant of Vaccinium emarginatum. Their structures were determined by detailed analysis of standard spectroscopic data (MS, IR, 1D, and 2D NMR) and comparison with data of known analogs. The isolates were evaluated for their cytotoxicity against the PC-3 and Du145 prostate cancer cell lines (as assessed by an MTT cell proliferation assay), as well as for their anti-inflammatory activity via the inhibition of nitric oxide production in lipopolysaccharide-induced murine macrophage RAW 264.7 cells. Among the isolates, the triterpenoid coumaroyl and feruloyl esters (1, 3: , and 4: ) exhibited strong cytotoxicity against PC-3 prostate cancer cells, with 85.6 - 90.2% inhibition at 10.0 µg/mL. The pomolic acid coumaroyl and feruloyl esters (1: and 3: ) also showed moderate anti-inflammatory activity against nitric oxide production in lipopolysaccharide-induced RAW 264.7 cells, with 59.2 (± 1.0) and 47.1% (± 0.2) inhibition at 12.5 µg/mL, respectively.

Chinese Herbal Medicine Ganoderma tsugae Displays Potential Anti-Cancer Efficacy on Metastatic Prostate Cancer Cells.

Resistance to the current therapies is the main clinical challenge in the treatment of lethal metastatic prostate cancer (mPCa). Developing novel therapeutic approaches with effective regimes and minimal side effects for this fatal disease remain a priority in prostate cancer study. In the present study, we demonstrated that a traditional Chinese medicine, quality-assured Ganoderma tsugae ethanol extract (GTEE), significantly suppressed cell growth and metastatic capability and caused cell cycle arrest through decreasing expression of cyclins in mPCa cells, PC-3 and DU145 cells. GTEE also induced caspase-dependent apoptosis in mPCa cells. We further showed the potent therapeutic efficacy of GTEE by inhibiting subcutaneous PC-3 tumor growth in a xenograft model. The in vitro and in vivo efficacies on mPCa cells were due to blockade of the PI3K/Akt and MAPK/ERK signaling pathways associated with cancer cell growth, survival and apoptosis. These preclinical data provide the molecular basis for a new potential therapeutic approach toward the treatment of lethal prostate cancer progression.

Ganoderma tsugae Inhibits the SREBP-1/AR Axis Leading to Suppression of Cell Growth and Activation of Apoptosis in Prostate Cancer Cells.

Recent research suggests that the activation of lipid biosynthesis (lipogenesis) is linked with prostate cancer (PCa) malignancy. Sterol regulatory element-binding protein-1 (SREBP-1) is a key transcriptional regulator controlling lipogenesis. Moreover, androgen receptor (AR) has been well defined to play an important role in lethal PCa aggressiveness from androgen-responsive to castration-resistant status. In this study, we showed that the quality-assured Ganoderma tsugae ethanol extract (GTEE), a Chinese natural and herbal product, significantly inhibited expression of SREBP-1 and its downstream genes associated with lipogenesis in PCa cells. Through inhibiting SREBP-1, GTEE reduced the levels of intracellular fatty acids and lipids in PCa cells. Importantly, GTEE also downregulated the expression of AR and prostate-specific antigen (PSA) in both androgen-responsive and castration-resistant PCa cells. By blocking the SREBP-1/AR axis, GTEE suppressed cell growth and progressive behaviors, as well as activating the caspase-dependent apoptotic pathway in PCa cells. These data provide a new molecular basis of GTEE for the development of a potential therapeutic approach to treat PCa malignancy.

Characterization of Secondary Metabolites from Purple Ipomoea batatas Leaves and Their Effects on Glucose Uptake.

Ipomoea batatas has long been used in folk medicine for the treatment of hyperglycemia or as a food additive for the prevention of type 2 diabetes. However, neither the plant extract nor its active components have been evaluated systematically. In this work four crude extracts, including n-hexane- (IBH), 95% MeOH- (IBM), n-BuOH- (IBB), and H2O-soluble (IBW) fractions, were prepared by fractionation of a methanolic extract of purple I. batatas leaves. Twenty-four pure compounds 1-24 were then isolated by various chromatographic techniques and their structures identified from NMR and MS data. Glucose uptake assays in differentiated 3T3-L1 adipocytes and rat primary hepatocytes, as well as western blot analysis, were carried out to evaluate the antidiabetic activity of this species. The IBH crude fraction, with methyl decanoate (22) as a major and active compound, showed the greatest effect on glucose uptake, most likely via activation of Glut4 and regulation of the PI3K/AKT pathway. Quercetin 3-O-ß-d-sophoroside (1), quercetin (3), benzyl ß-d-glucoside (10), 4-hydroxy-3-methoxybenzaldehyde (12), and methyl decanoate (22) could be important components contributing to the antidiabetic effects. We conclude that purple I. batatas leaves have potential as an antidiabetic plant source and the active constituents 1, 3, 10, 12, and 22 are promising lead candidates for future investigation.

Improvement of enzymatic cross-linking of ovalbumin and ovotransferrin induced by transglutaminase with heat and reducing agent pretreatment.

The effects of transglutaminase (TGase, 1.0 unit/mL) with heat (95 °C, 5 min), 2-mercaptoethanol (2-ME, 0.83 %), and l-cysteine (l-Cys, 50 mM) pretreatment on the cross-linking of ovalbumin (OVA) and ovotransferrin (OVT) were investigated. SDS-PAGE revealed that although the polymerization of OVA and OVT did not occur after 3 h of incubation at 40 °C with TGase, OVA polymerized into high molecular weight polymers following TGase with 2-ME and heat pretreatment after 3 h of incubation. The surface hydrophobicity and reactive sulfhydryl (SH) groups of OVA samples significantly increased from 4065.7 ± 136.7 and 89.3 ± 1.2 SH groups (µmol/g) to 31483.6 ± 342.7 and 119.5 ± 3.7 SH groups (µmol/g), respectively. Similar results were obtained for OVT with TGase and l-Cys pretreatment and a 3-h incubation at 40 °C. The use of TGase, a reducing agent, and/or heat pretreatment can be used for the polymerization of OVA and OVT.

Cell type-specific effects of Adenosine 5'-triphosphate and pyrophosphate on the antitumor activity of doxorubicin.

Extracellular ATP is an important signaling molecule mediating quite divergent specific biological effects. Even though recent studies suggest a potential role of ATP in cancer progress, its real impact in chemotherapeutic efficacy remains unclear. In the present study, we investigated the effect of ATP on the cytotoxicity of doxorubicin in various cancer cell types and found that ATP had no effect on doxorubicin cytotoxicity in colon, prostate, breast, and cervical cancers or in osteosarcoma. In contrast, ATP has divergent effects on lung cancer cells: it can protect against doxorubicin-induced cell death in non-metastatic lung cancer CL1.0 cells, but not in highly metastatic CL1.5 cells. Both apoptotic (characterized by sub-G(1) peak, caspase 3 activation, poly(ADP-ribose) polymerase-1 cleavage) and necrotic (characterized by propidium iodide uptake and ROS production) features induced by doxorubicin in CL1.0 cells were reduced by ATP. In addition, ATP attenuated p53 accumulation, DNA damage (assessed by poly(ADP-ribose) formation and the comet assay) and topoisomerase II inhibition after doxorubicin treatment, and doxorubicin cytotoxicity was diminished by the p53 inhibitor pifithrin-α. Moreover, UTP, UDP, ADP, and pyrophosphate sodium pyrophosphate tetrabasic decahydrate diminished the antitumor effect of doxorubicin in CL1.0 cells, whereas purinergic P2 receptors antagonists did not abrogate the action of ATP. In summary, ATP fails to alter the antitumor efficacy of doxorubicin in most cancer cell types, except in CL1.0 cells, in which pyrophosphate mediates the cell protection afforded by ATP via attenuation of reactive oxygen species production, DNA damage, p53 accumulation, and caspase activation.

Rhein induces apoptosis in human breast cancer cells.

Human breast cancers cells overexpressing HER2/neu are more aggressive tumors with poor prognosis, and resistance to chemotherapy. This study investigates antiproliferation effects of anthraquinone derivatives of rhubarb root on human breast cancer cells. Of 7 anthraquinone derivatives, only rhein showed antiproliferative and apoptotic effects on both HER2-overexpressing MCF-7 (MCF-7/HER2) and control vector MCF-7 (MCF-7/VEC) cells. Rhein induced dose- and time-dependent manners increase in caspase-9-mediated apoptosis correlating with activation of ROS-mediated activation of NF-κB- and p53-signaling pathways in both cell types. Therefore, this study highlighted rhein as processing anti-proliferative activity against HER2 overexpression or HER2-basal expression in breast cancer cells and playing important roles in apoptotic induction of human breast cancer cells.

Ganoderma tsugae Induces S Phase Arrest and Apoptosis in Doxorubicin-Resistant Lung Adenocarcinoma H23/0.3 Cells via Modulation of the PI3K/Akt Signaling Pathway.

Ganoderma tsugae (GT) is a traditional Chinese medicine that exhibits significant antitumor activities against many types of cancer. This study investigated the molecular mechanism by which GT suppresses the growth of doxorubicin-resistant lung adenocarcinoma H23/0.3 cells. Our results reveal that GT inhibits the viability of H23/0.3 cells in vitro and in vivo and sensitizes the growth suppression effect of doxorubicin on H23/0.3 cells. The data also show that GT induces S phase arrest by interfering with the protein expression of cyclin A, cyclin E, CDK2, and CDC25A. Furthermore, GT induces cellular apoptosis via induction of a mitochondria/caspase pathway. In addition, we also demonstrate that the suppression of cell proliferation by GT is through down-regulation of the PI3K/Akt signaling pathway. In conclusion, this study suggests that GT may be a useful adjuvant therapeutic agent in the treatment of lung cancer.

Association of adenoid hyperplasia and bacterial biofilm formation in children with adenoiditis in Taiwan.

The adenoid is a bacterial reservoir that contributes to chronic otolaryngologic infections. Staphylococcus aureus (S. aureus) is a common pathogen in the adenoid. The increase of antibiotic resistance in S. aureus has become an important issue in public health. The aim of this study was to compare adenoid hyperplasia and biofilm formation in children with S. aureus adenoiditis in Taiwan. The patients were divided into methicillin-resistant and methicillin-sensitive S. aureus groups according to the S. aureus obtained from adenoid tissue after antibiotic susceptibility testing. Adenoid hyperplasia was assessed by lateral cephalometry, and the severity of sinusitis was evaluated by Water's view. Microbiological investigation of available S. aureus isolates was performed by in vivo morphological observation and an in vitro bacterial biofilm assay. Sixty isolates of S. aureus were identified in 283 children (21.2%) after adenoidectomy, of which 21 (35%) were methicillin-resistant S. aureus (MRSA). The severity of adenoid hyperplasia and extensive biofilm formation were more prominent in patients infected with methicillin-resistant S. aureus than in those infected with methicillin-sensitive S. aureus (MSSA). The primary outcome of this study was to provide evidence that S. aureus constituted a significant portion of the adenoidal pathogens. The secondary outcome of this study was that MRSA adenoiditis may be associated with adenoid hyperplasia and biofilm formation.

Transient ischemia/hypoxia enhances gentamicin ototoxicity via caspase-dependent cell death pathway.

Aminoglycoside ototoxicity is a common cause of drug-induced hearing loss. Toxicity is dose related, but some patients may still develop hearing loss even under safe dosage. Apart for genetic idiosyncrasy, indirect evidences imply that ischemia may increase the aminoglycoside ototoxic sensitivity because common clinical situations associated with cochlear ischemia such as noise, sepsis, and shock are known to augment the development of aminoglycoside ototoxicity. At present, a direct interaction of cochlear ischemia and aminoglycoside ototoxicity is still lacking. This study demonstrated a direct evidence of increased gentamicin (GM) ototoxic sensitivity in chronic guinea pig models of transient cochlear ischemia. No permanent auditory changes were observed after a single dose of GM (125 mg/kg) or after transient cochlear ischemia for 30 min. Persistent and significant auditory threshold shift was detected when GM was given after transient cochlear ischemia. Cochlear hair cells and spiral ganglion neurons are the major regions affected. Apoptosis contributes to hair cell death during acute interaction of ischemia and GM ototoxicity. Increased apoptotic cell death was also depicted when GM crossreacted with hypoxia in vitro, using cochlear cell lines. Generation of reactive oxygen species, loss of mitochondrial membrane potential, calcium release, and caspase-dependent apoptotic cell death were shown during the interaction of hypoxia and GM ototoxicity in vitro. This synergistic ototoxicity may be critical to aminoglycoside-induced hearing loss in clinical scenarios. The results should improve our understanding of the interacting mechanism and potential preventive strategy to aminoglycoside ototoxicity.

Hyperbaric oxygen upregulates cochlear constitutive nitric oxide synthase.

BACKGROUND: Hyperbaric oxygen therapy (HBOT) is a known adjuvant for treating ischemia-related inner ear diseases. Controversies still exist in the role of HBOT in cochlear diseases. Few studies to date have investigated the cellular changes that occur in inner ears after HBOT. Nitric oxide, which is synthesized by nitric oxide synthase (NOS), is an important signaling molecule in cochlear physiology and pathology. Here we investigated the effects of hyperbaric oxygen on eardrum morphology, cochlear function and expression of NOS isoforms in cochlear substructures after repetitive HBOT in guinea pigs. RESULTS: Minor changes in the eardrum were observed after repetitive HBOT, which did not result in a significant hearing threshold shift by tone burst auditory brainstem responses. A differential effect of HBOT on the expression of NOS isoforms was identified. Upregulation of constitutive NOS (nNOS and eNOS) was found in the substructures of the cochlea after HBOT, but inducible NOS was not found in normal or HBOT animals, as shown by immunohistochemistry. There was no obvious DNA fragmentation present in this HBOT animal model. CONCLUSIONS: The present evidence indicates that the customary HBOT protocol may increase constitutive NOS expression but such upregulation did not cause cell death in the treated cochlea. The cochlear morphology and auditory function are consequently not changed through the protocol.

Engineering of Escherichia coli for targeted delivery of transgenes to HER2/neu-positive tumor cells.

Targeting of non-phagocytic tumor cells and prompt release of gene cargos upon entry into tumors are two limiting steps in the bacterial gene delivery path. To tackle these problems, the non-pathogenic Escherichia coli strain BL21(DE3) was engineered to display the anti-HER2/neu affibody on the surface. After co-incubation with tumor cells for 3 h, the anti-HER2/neu affibody-presenting E. coli strain was selectively internalized into HER2/neu-positive SKBR-3 cells. The invasion efficiency reached as high as 30%. Furthermore, the bacteria were equipped with the phage ϕX174 lysin gene E-mediated autolysis system. Carrying the transgene (e.g., eukaryotic green fluorescent protein, GFP), the tumor-targeting bacteria were subjected to the thermal shock to trigger the autolysis system upon entry into HER2/neu-positive cells. Flow cytometric analysis revealed that 3% of infected cells expressed GFP 24 h post thermal induction. Overall, the results show a promise of the proposed approach for developing bacteria as a delivery carrier.

Ile/Ile homozygosity at codon 655 of HER2 in schwannoma.

PURPOSE: This study aimed to determine the genetic role of HER2, one of the epidermal growth factor receptor (EGFR) family, in schwannoma. The latter is a neogrowth of myelin-producing Schwann cells in peripheral nerves, inducible by N-nitrosoethylurea in animals with mutation in the neu gene (homologous gene of human HER2 protein). METHODS: In this study we obtained genomic DNA samples from tissue blocks of schwannoma, initially by xylene treatment and alcohol extraction, followed by use of the DNA extraction kit. Evaluation of this genetic polymorphism in our subjects was conducted by direct nucleotide sequencing or restriction enzyme analyses after PCR work. RESULTS: There were thirty extracted DNA samples from tissue blocks of schwannoma, and all were Ile/Ile homozygotes after genotype analyses. Two individuals received the leukocyte DNA extraction after peripheral blood sampling, both showing Ile/Ile homozygosity. This study gave the impression of an association of the HER2 polymorphism at codon 655 with tumorigenesis of schwannoma. Although the majority of the Taiwanese showed Ile/Ile homozygosity (about 83%), the present study revealed a 100% carriage rate among the tissue blocks from our subjects with schwannoma. CONCLUSION: Ile/Ile homozygosity at codon 655 of HER2 in schwannoma may imply some role in tumorigenesis of Ile655Val allele of HER2 in this nerve tumor.

Phenylpropanoids and lignoids from the whole plant of Vaccinium emarginatum and their cytotoxicity against prostate cancer cells.

One new naturally occurring quinone, 3',4'-dihydroxy-1,2,6-trimethoxy-[1,1'-biphenyl]-4(1H)-one (1), one new diarylpropane, emarginone A (2), and one new neolignan, emarginone B (3), along with eighteen known compounds have been isolated from the chemical investigation of the EtOAc-soluble fraction of the Vaccinium emarginatum whole plant methanolic extract. The new structures were elucidated by combined analysis of spectroscopic analytical methods and comparison with the literature data obtained from known analogues. In addition, the cytotoxicity of compounds 2, 4, and 14-20 against Du145 and PC-3 prostate cancer cell lines using MTT cell proliferation assay was evaluated. Compounds 2 and 19 showed most potent cytotoxicity against Du145 with IC50 values of 7.53 and 6.63 µg/mL, respectively. Furthermore, compounds 2, 17, and 19 also exhibited significant cytotoxicity against PC-3 with IC50 values ranging from 3.44-6.64 µg/mL.

New flavonoids, emarginin A-C from Vaccinium emarginatum Hayata.

Phytochemical investigation of methanolic extract of the whole plants of Vaccinium emarginatum allowed for the characterization of one epicatechin derivative (1) that was isolated from a natural source for the first time and three new flavonoids, emarginin A (2), emarginin B (3), and emarginin C (4), together with 11 known compounds (5-15). The structures of compounds 1-4 were elucidated by combination of spectroscopic analysis (MS, IR, and NMR) and by comparison with that of literature analogues. Compounds 1-8 and 11-15 were evaluated for their preliminary in vitro anti-proliferative activity against Du145 and PC-3 prostate cancer cell lines. Among them, compound 15 exhibited most potent cytotoxicity against Du145 and PC-3 cells, with IC50 values of 8.46 and 10.98 µM, respectively. Furthermore, compounds 1-7 were assessed for their anti-inflammatory potential against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 cells. Compound 4 exhibited moderate anti-inflammatory activity, with an IC50 value of 27.99 µM.

Octarepeat changes of prion protein in Parkinson's disease.

Polymorphism in prion protein (PrP) is related to different phenotypes of spongiform encephalopathies and some mental illnesses. The octarepeat region of PrP, encompassing the codon 51 through 91, is related to cellular anti-oxidation function and may play a role in genetic contribution of PrP polymorphism to neurodegeneration, such as Parkinson's disease (PD). We analyzed the genomic patterns of PrP gene from 528 subjects and found a predominance of Met/Met variant at codon 129 of PD subjects without significant difference (97.3%, and 96.5% in controls). But among PD subjects there were one with heterozygosity of silent nucleotide substitution (NS) on octarepeats (R1-2-3g-3-4/R1-2-2-3-4) and three with heterozygosity of single copy deletion (CD) on octarepeats (R1-2-3-4/R1-2-2-3-4). Consistent genomic DNA and cDNA sequences were found in a PD subject without any octarepeat changes and the one with NS, but R1-2-3g-3-4/R1-2-2-3-4 of cDNA pattern occurred in the one with genomic CD. This is the first report of the polymorphic PrP octarepeat change among those with parkinsonism. We proposed a hypothesis about an initial secondary hairpin structure of the template strand followed by the transcript "shift backward" due to the high homology of the sequences between R2 and R3 motifs while synthesizing RNA. This phenomenon may be a key step of neurodegeneration resulting from PrP polymorphism and require further studies.