Treatment of PTEN-Null Breast Cancer by a Synthetic Lethal Approach Involving PARP1 Gene Silencing.

The loss of the phosphatase and tensin homolog (PTEN) deleted from chromosome 10 is frequently observed in a variety of human cancers and appears to be an ideal target in synthetic lethality-based treatment. In this study, the synthetic lethal interaction between PTEN loss and the gene silencing of poly [ADP-ribose] polymerase 1 (PARP1) was examined in human triple-negative breast cancer cells (PTEN-null MDA-MB-468 and PTEN-positive MDA-MB-231 cells). Polycation liposomes previously developed by us were employed to deliver the small interfering ribonucleic acid (siRNA) targeted toward PARP1 (siPARP1) into the cancer cells. The silencing of the PARP1 gene exerted a cytocidal effect on the MDA-MB-468 cells but had no effect on the MDA-MB-231 cells and the human umbilical vein endothelial cells employed as normal cells. The simultaneous knockdown of PARP1 and PTEN in the MDA-MB-231 cells resulted in the significant inhibition of cell growth. The data suggest that the effects of the PARP1 knockdown on the cells were dependent on the PTEN status. A significant increase in the DNA breaks and the extent of apoptosis, possibly due to the failure of DNA repair, was observed upon PARP1 knockdown in the MDA-MB-468 cells compared with the case in the MDA-MB-231 cells. Our findings suggest that the synthetic lethal approach via PARP1 gene silencing holds promise for the treatment of patients with PTEN-null breast cancer.

ICH Culture: Its Maintenance and Development.

The founding industry members (European Federation of Pharmaceutical Industries and Associations [EFPIA], Japanese Pharmaceutical Manufacturers Association [JPMA], and Pharmaceutical Research and Manufacturers of America [PhRMA]) of the International Council for Harmonisation (ICH) have a 25-year track record of the contribution to ICH. Given that further globalization of ICH is expected, we should value this legacy and maintain the current ICH culture and its principles of "benefit to the patients first" and "science-based approach," through which industry members would ensure transparency and objectivity in their ICH activities. In order to maintain and develop the culture of the ICH and its current momentum, a 2-way approach is important: (1) sharing common views through dialogues among leaders of each industry association, such as through the Industry Executive Council, and (2) spreading the values through grassroots activities involving wider stakeholders in global forums such as DIA, as platforms for sharing the knowledge, views, and culture of ICH across the globe.

Susceptibility of PTEN-positive metastatic tumors to small interfering RNA targeting the mammalian target of rapamycin.

PTEN-positive tumors are not susceptible to the treatment with rapamycin, an inhibitor of the mammalian target of rapamycin (mTOR). Here, we determined the susceptibility of PTEN-positive cells to small interfering RNA for mTOR (si-mTOR) by using a novel liposomal delivery system. We prepared dicetyl phosphate-tetraethylenepentamine-based polycation liposomes (TEPA-PCL) decorated with polyethylene glycol (PEG) grafting Ala-Pro-Arg-Pro-Gly (APRPG), a VRGFR-1-targeting peptide. APRPG-PEG-decorated TEPA-PCL carrying si-mTOR (APRPG-TEPA-PCL/si-mTOR) had an antiproliferative effect against B16F10 murine melanoma cells (PTEN-positive) and significantly inhibited both the proliferation and tube formation of mouse 2H-11 endothelial-like cells (PTEN-positive). APRPG-TEPA-PCL/si-mTOR treatment did not induce Akt phosphorylation (Ser473) in either B16F10 or 2H-11 cells although there was strong phosphorylation of Akt in response to rapamycin treatment. Intravenous injection of APRPG-TEPA-PCL/si-mTOR significantly suppressed the tumor growth compared with rapamycin treatment in mice bearing B16F10 melanoma. These findings suggest that APRPG-TEPA-PCL/si-mTOR is useful for the treatment of PTEN-positive tumors.

Polycation liposomes as a vector for potential intracellular delivery of microRNA.

BACKGROUND: We previously developed a microRNA (miRNA) delivery system by using dicetyl phosphate-tetraethylenepentamine-based polycation liposomes (TEPA-PCL), applied it to miR-92a delivery, and demonstrated its gene-silencing potential and effective anti-angiogenic effects. In the present study, we investigated the mechanism of intracellular delivery of cholesterol-grafted miR-92a (miR-92a-C) into cells. METHODS: To investigate the intracellular distribution of miR-92a-C/TEPA-PCL complex, we used human umbilical vein endothelial cells and examined certain points after transfection: (i) the time-course of miR-92a-uptake into the cells; (ii) the endocytosis pathway induced by miR-92a-C/TEPA-PCL; (iii) the capability of miR-92a-C/TEPA-PCL to escape from the endosomes; and (iv) the release of miR-92a-C from TEPA-PCL in the cytoplasm. RESULTS: Our data indicated that miR-92a-C formulated in TEPA-PCL accumulated in and was spread throughout the cytoplasm in a time-dependent manner, and was taken up into the cells by macropinosome-mediated endocytosis. In addition, the surface charge of miR-92a-C/TEPA-PCL was neutral at pH 7.4 and was charged positively at around pH 5.5, which is the inner pH of endosomes. When the late endosomes/lysosomes were stained with Lysotracker, miR-92a-C/TEPA-PCL efficiently escaped from the endosomes into the cytoplasm, possibly through the proton-sponge effect. Furthermore, miR-92a-C spread throughout whole cytoplasm and did not co-localize completely with TEPA-PCL, indicating that some of the miR-92a-C was present in free form in the cytoplasm. CONCLUSIONS: The results of the present study suggest that TEPA-PCL-based lipoplexes have an excellent potential to deliver microRNAs into the cytoplasm of cells and to induce RNA silencing action mediated by microRNAs and other small RNAs.

Development of a miR-92a delivery system for anti-angiogenesis-based cancer therapy.

BACKGROUND: RNA interference has received much attention as a novel therapeutic strategy. MicroRNA (miRNA) appears to be promising as a novel nucleic-acid medicine because it is able to suppress a series of protein expression that relates to a specific event such as angiogenesis. In the present study, we used dicetyl phosphate-tetraethylenepentamine-based polycation liposomes (TEPA-PCL) as a delivery system for miR-92a, one of the miRNAs regulating angiogenesis, and attempted to deliver miR-92a to angiogenic endothelial cells for the development of cancer therapy by anti-angiogenesis. METHODS: Cholesterol-grafted miR-92a (miR-92a-C) was bound to TEPA-PCL, and the ratio of nitrogen of TEPA-PCL to phosphorus of miR-92a-C (N/P ratio) was optimized. This complex was transfected into human umbilical vein endothelial cells (HUVECs), and the intracellular localization of miR-92a-C was observed under a confocal laser-scanning microscope by the use of fluorescein isothiocyanate-labeled miR-92a-C. After transfection of HUVECs with miR-92a-C/TEPA-PCL, the expression of miR-92a-target proteins (e.g. integrin α5, mitogen-activated protein kinase kinase 4, sphingosine-1-phosphate receptor 1) was examined by western blotting, and a tube formation assay was performed. RESULTS: The complex of miR-92a-C with TEPA-PCL was formed and miR-92a-C remained stable with TEPA-PCL at the N/P ratio of 10. After transfection of HUVECs with miR-92a-C complex, miR-92a-C spread into the whole cytoplasm of the cells without any change of cellular morphology, and the expression of several proteins encoded by miR-92a-target genes was suppressed. Furthermore, the capability of forming capillary tubes was impaired in complex-treated HUVECs. CONCLUSIONS: We have developed a miR-92a delivery system into angiogenic endothelial cells by the use of TEPA-PCL. These results suggest that miR-92a-C/TEPA-PCL is promising for the treatment of tumors via the suppression of angiogenesis.

Severe interstitial cystitis associated with Sjögren's syndrome.

A 53-year-old woman presented with oliguria, urinary frequency, abdominal pain and severe edema of the lower extremities. Her serum creatinine was 8.1 mg/dl. Computed tomographic and ultrasonographic studies showed a severely dilated urinary bladder, and bilateral hydroureteronephrosis. Examination of a urinary bladder biopsy specimen showed subepithelial edema and infiltration by lymphocytes and plasmacytes. However, the patient complainted of dry mouth and dry eyes. Ophthalmologically, the Schirmer test was positive. A biopsy of the minor salivary glands in the lip showed chronic sialoadenitis. A diagnosis of Sjögren's syndrome complicated by interstitial cystitis was made. Since she had been anuric, secondary to urinary obstruction, intermittent self-catheterization was started. Combination of corticosteroid and cyclosporin therapy was initiated. Spontaneous urination began, and gradually the patient's symptoms remitted. After 8 months of therapy, bladder capacity increased from 140 ml to 350 ml, and she voided approximately 1,200 ml by herself and 600 ml by catheterization daily. This case suggests that when severe interstitial cystitis is associated with Sjögren's syndrome, a therapeutic trial of corticosteroids and cyclosporin may be beneficial.

Intravascular embolization therapy in a patient with an enlarged polycystic liver.

Because the kidneys in patients with autosomal dominant polycystic kidney disease (ADPKD) are usually supplied by well-developed arteries, the authors attempted renal contraction therapy in such patients with renal transcatheter arterial embolization (TAE) using intravascular coils. In most patients with marked nephromegaly, renal TAE was effective. However, in patients with marked hepatomegaly without significant nephromegaly, renal TAE was not effective, and hepatic treatment was always required. In June 2001, the authors obtained approval for a new treatment,"TAE for enlarged polycystic liver," from an ethics committee discussing new treatment at their hospital. A 56-year-old man undergoing hemodialysis for 2 months was referred to the authors' institute with the complaint of severe abdominal distension and loss of appetite in March 2001. Most of the liver (about 90%) had been replaced by multiple cysts, and near-intact hepatic parenchyma was quite scarce. The kidneys were quite small compared with the liver. Angiography results showed that almost all hepatic arterial branches were well developed, although most of the portal vein was obstructed, and only the left medial portal vein was spared; the former corresponded to the hepatic region replaced by multiple cysts and the latter to the preserved intact hepatic parenchyma. The target of TAE was the hepatic arterial branches of the former. Microcoils were used as embolization material. Two years after TAE, abdominal distension has markedly decreased because of decrease in liver size (to 54% of the previous value), and muscle and fat volume in the thoracic region have increased owing to improvement of appetite. Ascites became obscure. Nutrition and activities of daily living have improved. Hepatic TAE may be an option for treatment of patients in poor condition with symptomatic polycystic liver.

Chinese herbs and bone disease.

We treated a patient with an unusual bone disease at least partly associated with Chinese herbs. Seven years after 65-year-old man had begun to consume Chinese herbs, multifocal osteoarthralgias were noted, and the patient was hospitalized for renal dysfunction (serum creatinine, 2.8 mg/dl; urea nitrogen, 19 mg/dl). Fanconi syndrome also was apparent. A renal biopsy specimen showed tubulo-interstitial fibrosis. Chinese herbs were discontinued and prednisolone was started, but bone and joint pain as well as renal function gradually worsened. Four years later, creatinine was 9.0 mg/dl and alkaline phosphatase was 571 IU/l. As bone scintigraphy revealed localized asymmetric lesions, Paget's disease of bone was suspected at first. However, neither osteosclerosis nor hypertrophy was seen in radiographs. Based on a bone specimen histology we diagnosed as mixed-type renal osteodystrophy including osteomalacia and osteitis fibrosa. Mosaic pattern of cement lines was not present. This case was not compatible with either Paget's disease or typical renal osteodystrophy as seen in dialysis patients. Etidronate disodium was effective in alleviating bone symptoms. The patient's bone disorder may be a new disease at least partly related to Chinese herbs independently of nephropathy.

Histomorphometric features of bone in patients with primary and secondary hypoparathyroidism.

BACKGROUND: Idiopathic adynamic bone disease (ABD) in dialysis patients is characterized by low serum parathyroid hormone (PTH) concentration. Whether ABD itself causes serious disease is controversial. Fuller understanding of both primary hypoparathyroidism and secondary hypoparathyroidism resulting in a long-standing low-PTH state may shed light on properties of ABD. METHODS: We performed histomorphometric analysis in bone specimens from biopsy in two female patients with primary hypoparathyroidism and in an autopsy specimen of bone from a male patient with secondary hypoparathyroidism related to long-term hemodialysis; respective ages, 45, 58, and 65 years; dialysis duration, 6 years, 2 months, and 30 years; lumbar bone mineral density, 2.88, 2.43, and 4.1 SD above the normal mean; and serum intact PTH, <5, <20, and <84 pg/mL (mean, 30.4). Tetracycline labeling was performed in the first two cases. RESULTS: Histomorphometric analysis in the first two cases indicated a diagnosis of ABD, since no tetracycline labeling could be seen along most of trabecular bone surfaces, total osteoid volume was decreased, and fibrous tissue was minimal. Bone volume was preserved, and the dense bone-trabecular connectivity was noted, with normal lamellar structure. A small number of hump-like structures protruded from the quiescent surface of trabecular bone, a pattern which has been called "minimodeling." Tetracycline label was observed in only a small area within trabecular bone in patient 1, and at a region of trabecular bone surface showing minimodeling in patient 2. The third case was also diagnosed as ABD; cancellous lamellar structure and bone volume were normal, although trabecular connectivity was poor and island bone was relatively prominent. Minimodeling was evident. Minimodeling bone volume/total bone volume in these three cases was 9.0%, 13.1%, and 6.8%, respectively; number of minimodeling sites/total bone volume (N/mm2) was 4.9, 8.6, and 9.0, respectively. CONCLUSION: Bone formation mechanism by minimodeling might contribute to preserving bone volume in dialysis patients with hypoparathyroidism, even in the absence of remodeling stimulated by PTH.

Renal contraction therapy for enlarged polycystic kidneys by transcatheter arterial embolization in hemodialysis patients.

Kidneys of patients with autosomal dominant polycystic kidney disease (ADPKD) usually continue to increase in size, even after patients begin dialysis therapy, and the mass effects may lead to severe complications. Such external conventional therapies as surgical and laparoscopic procedures have not yielded satisfactory results. Because kidneys in patients with ADPKD usually are supplied by well-developed arteries, we attempted renal contraction therapy in patients with ADPKD by renal transcatheter arterial embolization (TAE) using intravascular coils. After obtaining informed consent, we selected anuric patients on dialysis therapy with markedly distended abdomens or macroscopic hematuria. Between October 1996 and December 2000, a total of 64 patients were treated. Renal size, abdominal circumference, dry weight, hematocrit, and insulin-like growth factor-I were measured before TAE and 3, 6, and 12 months after TAE. Renal sizes decreased to 73.8% +/- 12.0%, 61.7% +/- 14.7%, and 53.4% +/- 11.6% of preinterventional values at 3, 6, and 12 months after therapy, respectively (P < 0.0001). Abdominal circumference and dry weight were significantly decreased at 3, 6, and 12 months (P < 0.0001) compared with baseline values before therapy. Hematocrits increased sequentially after 3, 6, and 12 months (P < 0.0001). Levels of insulin-like growth factor-I an index of nutritional status, significantly increased at 3, 6, and 12 months compared with the baseline value (P < 0.001). This therapy was effective for all patients. Serious complications were not seen after this treatment, although such minor complications as fever and flank pain were observed within the first week after the procedure. Our internal treatment with TAE is a safe and effective procedure that has resulted in improvement in the quality of life and nutritional status of patients with ADPKD.