A novel HER2 inhibitor TAK-285 overcomes trastuzumab resistance of HER2-over-expressing breast cancer

Abstract #3143

Background: The anti-HER2 antibody trastuzumab has been proven highly effective in the treatment of HER2-expressing breast cancers clinically. However, the continuous administration often leads to drug resistance, the mechanism of which is not well understood. Here we present a new mechanism for trastuzumab-resistance. We also show TAK-285, a novel small molecule HER2/EGFR kinase inhibitor under clinical evaluation, overcomes the resistance to trastuzumab.
 Methods: A trastuzumab-resistant sub-clone (BT-474TR) of the HER2-positive human breast cancer line, BT-474, was established in house by serial passage in the presence of 5 μg/mL trastuzumab for over 5 months. Gene expression profiles of the clones were assessed using Affymetrix HG-U133 plus 2.0 human gene arrays and confirmed by real-time PCR. Target genes were depleted by siRNA-mediated knockdown and confirmed by real time-PCR and immunoblot. Effects on cell growth were assessed by the CellTiter-Glo luminescent cell viability assay (Promega).
 Results: BT-474TR cells exhibited modified expression of several genes including cofilin, compared to the parental BT-474 cells. Although immunoblotting using anti-cofilin antibody revealed no clear change in protein level, BT-474TR displayed significant increase in phosphorylation of cofilin. Gene-specific knockdown of cofilin-1 led to re-sensitization of BT-474TR to trastuzumab, though the cofilin-2 knockdown did not. Likewise, knockdown of either LIMK1 or PAK1, known to regulate cofilin-phosphorylation, resulted in similar re-sensitization of BT-474TR to trastuzumab. BT-474TR also exhibited increase in phosphorylation of both LIMK1 and PAK1. TAK-285 showed almost equivalent inhibitory activity against both BT-474 and BT-474TR proliferation in cell culture and in xenograft study, while trastuzumab did not affect the proliferation of BT-474TR in either condition
 Conclusions: These data suggest that activation of cofilin signaling pathway is a probable mechanism of trastuzumab resistance. PAK1/LIMK1/cofilin-1 inhibitors might therefore be useful in preventing or reversing trastuzumab resistance. The phosphorylation status of PAK1/LIMK1/cofilin might also serve as a biomarker of Trastuzumab-sensitivity. Moreover a novel HER2 inhibitor, TAK-285, might show benefit in the treatment of trastuzumab-resistant HER2-expressing breast cancers.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3143.

Prevalence of dementia in the rural island town of Ama-cho, Japan

BACKGROUND

With the striking increase in the number of elderly people in Japan, dementia has not only become a medical but also a social issue.

METHODS

We studied the prevalence of dementing disorders in a rural island town of Japan (Ama-cho), using a door-to-door 2-phase design.

RESULTS

Of the 120 persons screened as having cognitive impairment, 104 people were diagnosed as having dementia. The prevalence (cases/100 persons aged 65 years and older) was 11.0 for all types of dementia, 7.0 for Alzheimer's disease, 1.7 for vascular dementia, 0.53 for dementia with Lewy bodies, 0.74 for Parkinson's disease dementia, 0.21 for progressive supranuclear palsy, 0.11 for frontotemporal lobar degeneration and 0.74 for other dementia. The overall prevalence was higher in women for Alzheimer's disease and Parkinson's disease dementia, and in men, for vascular dementia and dementia with Lewy bodies.

CONCLUSION

We confirmed the overall prevalence of dementia in the elderly population aged 65 years and older to be 11.0. This finding is higher compared with previous reports in Japan.

[Safety management of bronchoscopic examination and treatment]

Safety management of bronchoscopic examination and treatment is devided into 3 phases. Patient information should be provided before the procedure. Also written informed conscent should be obtained after the information of advantage and disadvantage of examination/treatment. Bronchoscopists and well-trained nurses should manage both the procedure itself and patient condition. Through check up of patient is necessary to avoid late complications after the procedure. Due to the increase in the number of interventional bronchoscopies, the management of patients is getting more important. Safety management should be developed by wide-range of medical team including bronchoscopists, nurses and technical staff.

Association of epidermal growth factor receptor mutations in lung cancer with chemosensitivity to gefitinib in isolated cancer cells from Japanese patients

Somatic mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) gene are reported to be associated with clinical responsiveness of lung cancer to gefitinib, an EGFR tyrosine kinase inhibitor. To elucidate the association between somatic mutations and the pharmacological actions of gefitinib, the chemosensitivity of isolated cancer cells from the lungs of Japanese patients to gefitinib was examined by the collagen gel-droplet embedded culture drug sensitivity test in vitro. In 30 specimens isolated from non-small-cell lung cancer patients, mutations were observed in eight tumour specimens (27%) and chemosensitivity to gefitinib was observed in seven specimens (23%). However, somatic mutations were not predominantly associated with chemosensitivity to gefitinib in vitro. Both mutation and chemosensitivity frequencies in this study were higher than those reported in studies from the United States, indicating a possible ethnic difference. Moreover, both frequencies were much higher in females than in males. Since a gender difference in chemosensitivity to gefitinib was observed in isolated cancer cells in vitro, this suggests that gefitinib works in part through the suppression of EGFR signalling, but that other factors, including sex-related factors, may participate in gefitinib action.

In vivo suppression of mafA mRNA with siRNA and analysis of the resulting alteration of the gene expression profile in mouse pancreas by the microarray method

Maf is a family of transcription factor proteins that is characterized by a typical bZip structure, and one of the large mafs, mafA is a strong transactivator of insulin. To explore the role of mafA in the pancreas, we modified the mafA mRNA level in vivo in mice by the RNA interference (siRNA) technique and analyzed the resulting alteration of the expressed gene profile with a microarray system. The mafA expression level in siRNA-treated mice was reduced approximately 60% compared with control-siRNA-treated animals. Microarray analysis revealed changes in the expression level of several genes in the siRNA-treated mice, with prominent down-regulated expression of the genes encoding insulin, glucagon, and adipocytokines, suggesting possible role of mafA in the pathophysiological states of impaired metabolic responses or inflammatory reactions.

Pregnancy achieved following IVF-ET after surgery for infertility with perforate transverse vaginal septum and incomplete septate uterus: case report

Transverse vaginal septum is a rare congenital anomaly. Imperforate transverse vaginal septum causes marked clinical symptoms, and is diagnosed at a young age in most cases. Perforate transverse vaginal septum is difficult to detect due to the absence of symptoms. In this study, we report a case of a 33-year-old infertile female with a perforate transverse vaginal septum and incomplete septate uterus who had wished to bear a child for over ten years, and consulted our hospital. Transverse vaginal septum was considered to be an etiological factor for infertility. After surgery for transverse vaginal septum, in vitro fertilization achieved pregnancy.

Effect of lysed Enterococcus faecalis FK-23 on allergen-induced immune responses and intestinal microflora in antibiotic-treated weaning mice

BACKGROUND

Recent epidemiological studies have indicated that early life receipt of antibiotics may be associated with an increased risk of developing atopic disorder. Lysed Enterococcus faecalis FK-23 (LFK), a probiotic product of E faecalis, has been shown to have inhibitory effects on allergen-induced immune responses in mice.

OBJECTIVE

The purpose of this study was to evaluate the effects of LFK on immune responses and intestinal microflora in antibiotic-treated, and allergen-sensitized weaning mice.

METHODS

Three-week-old BALB/c mice were sensitized with cedar pollen allergen to establish the experimental model. The allergen-induced peritoneal accumulation of eosinophils, serum levels of total and allergen-specific immunoglobulin (Ig) E and IgG2a, and the intestinal bacterial flora were determined in the control, antibiotic, LFK and antibiotic-LFK groups (n = 7 in all groups). Orally administered erythromycin, one kind of macrolide antibiotic, was used for the experiments.

RESULTS

There was no significant difference in the allergen-induced peritoneal accumulation of eosinophils and serum specific IgE and IgG2a levels in erythromycin-treated mice compared to a control group. However, the ratio of serum total IgE to IgG2a levels was significantly increased in erythromycin-treated mice relative to that found either in LFK-treated mice or in erythromycin-treated mice with LFK supplementation. The total aerobes, total anaerobes and Enterococcus species of intestinal microflora were not significantly different among all groups. Lactobacillus species were distinctly eliminated in the mice exposed to erythromycin on day 7 and totally recovered in erythromycin-treated mice with LFK intervention on day 28, but could not be recovered in the erythromycin-treated mice without LFK intervention.

CONCLUSIONS

Our results suggest that LFK may improve the intestinal ecosystem disturbed by antibiotic use, and thereby prevent subsequent development of atopy. However, whether different antibiotics have different effects on immune responses needs to be addressed further.

Clinical characteristics of acute encephalopathy of obscure origin: a biphasic clinical course is a common feature

OBJECTIVE

To evaluate the clinical characteristics of acute encephalopathy of obscure origin (AE).

STUDY DESIGN

We examined clinical, imaging, and laboratory findings in children with AE. Specific subtypes of AE such as Reye's syndrome (RS), acute necrotizing encephalopathy (ANE), hemorrhagic shock and encephalopathy (HSE), acute encephalitis with refractory, repetitive partial seizures (AERRPS), and hemiconvulsion-hemiplegia syndrome (HH) were diagnosed. Other AE patients were regarded as non-specific subtype.

RESULTS

Nineteen patients were identified; specific AEs in 14 and non-specific AE in 5. Patients with RS, ANE, HSE frequently showed neuroimaging abnormalities (9/9) and significant elevation of liver enzymes (7/9) within 2 days after onset. Prognoses were extremely poor; early death in 6 and severe neurological sequelae in 3. Two of the 3 HH patients and 4 of the 5 non-specific AE patients showed biphasic clinical courses (AEBC); consciousness levels transiently improved following initial seizures and were exacerbated at the fourth to sixth days. In AEBC, neuroimaging abnormalities were rarely observed during the acute phase (1/5) but were detectable at clinical exacerbation. They rarely showed severely abnormal elevation in liver enzymes (1/6) and resulted in mild to moderate neurological sequelae (6/6).

CONCLUSION

A biphasic clinical course is a common feature in HH and non-specific AE.

Influence of pancreas transplantation alone on native renal function

Pancreas transplantation alone (PTA) has become an accepted treatment of nonuremic diabetic patients, when the risks of secondary complications of diabetes mellitus are greater than those of the surgical procedure and the posttransplant immunosuppression. As a decrease in native renal function is expected, we followed this parameter among patients who underwent PTA. From January 1997 through January 2005, we performed 69 PTA in 66 patients. All patients showed glucose hyperlability with hypoglycemic unawareness, or two or more diabetic complications as well as creatinine clearance (CrCl) > or = 45 mL/min. Immunosuppression was based on tacrolimus, mycophenolate mofetil and prednisone. Twenty-four hour CrCl were performed after all successful PTA. We divided patients in two groups according to the pretransplant CrCl: group 1, CrCl < or = 70 mL/min (n = 20) and group 2, CrCl > 70 mL/min (n = 25). The data were analyzed using Student's t-test (P < or = .05 was considered significant). Twenty-one patients were excluded from the analysis because of death (n = 5) or graft loss (n = 8) during the first year or follow-up shorter than 1 year (n = 8). The mean value of CrCl decreased 28.8% (85.0 +/- 31 versus 60.5 +/- 36 mL/min; P < .001). There was also a 39.3% reduction among group 1 subjects (P = .003), including 10 who displayed CrCl < or = 30 mL/min. There was also a 24.4% reduction among group 2 (P = .008), but no patient developed end-stage renal disease. In conclusion, native renal function decreased significantly after PTA, but was well tolerated among patients with CrCl > 70 mL/min. Patients with CrCl < 70 mL/min show a significant risk of worsened renal function.

Pancreas Retransplantation: Outcomes of 20 Cases

The objective of this paper was to evaluate our initial experience with pancreas retransplantation. From January 26, 1996 to February 2005, 285 pancreas transplantations were performed, including 20 (7%) retransplants. The causes of primary graft loss were graft thrombosis in 11 (55%, 7 venous and 4 arterial); 4 (20%) chronic rejections; 2 (10%) ischemia/reperfusion injury; 1 severe graft pancreatitis; 1 primary nonfunction; and 1 sepsis. Venous drainage was placed in the iliac vessels in 14 (70%), vena cava in 5 (25%), and portal drainage in 1. The exocrine drainage was vesical in 16 (80%) and enteric in 4 (20%). In 14 cases (70%), the primary graft was removed before and in 6 (30%) at the time of retransplantation. Immunosuppression was based on antilymphocyte induction, tacrolimus, mycophenolate mofetil, and steroids in all patients. One-year patient and graft survivals were 95% and 85%. In conclusion, pancreas retransplants were feasible with results comparable to a primary pancreas transplantation.

Functional changes induced by chronic UVA irradiation to cultured human dermal fibroblasts

Ultraviolet (UV) irradiation induces damage of the skin, and in particular, photoageing is known to be the result of chronic UV irradiation. Many investigations have attempted to clarify the mechanisms of photoageing induced by chronic UVA irradiation, but consensus has not been achieved yet by in vivo experiments, mostly due to differences among UV sources and animals used for experiments. In vitro experiments have shown that a single exposure to UVA irradiation causes overexpression of matrix metalloproteinases and denaturation of collagen, but the mechanisms of the photoageing effects of chronic UVA irradiation are still unclear. To examine the effects of chronic UVA irradiation, we used an in vitro fibroblast cellular ageing system as a model of photoageing. Chronic UVA irradiation of normal human fibroblasts induced shortening of the cellular life span and an increase of cellular diameter, in parallel with expression of senescence-associated beta-galactosidase. Extracellular degradation enzyme, matrix metalloproteinase 1 (MMP-1) was overexpressed after repeated UVA irradiation, but tissue inhibitor of metalloproteinase 1 (TIMP-1) expression was hardly changed by chronic UVA irradiation. We conclude that chronic UVA irradiation of normal human fibroblasts induces cellular functional changes, leading to accelerated cellular ageing and MMP-1 overexpression.

Adsorption of gaseous formaldehyde and carboxylic acids by ammonium-ion-exchanged α-zirconium phosphate

Ammonium-ion-exchanged alpha-Zr(HPO(4))(2)H(2)O (alpha-ZrP) was obtained as a single phase with the interlayer distance of 9.4 A by the ion-exchange of proton with ammonium ion. The ammonium ion-exchanged alpha-ZrP could adsorb ill-smelling gases, such as formaldehyde and carboxylic acids (formic acid, acetic acid, propionic acid, and butyric acid). The adsorption amounts of carboxylic acids increased in the order, butyric acid<propionic acid<acetic acid<formic acid, whereas the adsorption amount of formaldehyde was the same as that of butyric acid. It was cleared that the adsorbed formaldehyde was partially decomposed to formic acid and methanol by self oxidation-reduction reaction in the interlayer region as evidenced by solid-state NMR. Thereby the interlayer distance after the adsorption of formaldehyde expanded to 14.4 A. In the case of formic acid, it was cointercalated into the interlayer region, and the interlayer distance expanded to 11.1 A. On the other hand, the interlayer distance of the other carboxylic acid-adsorbed compounds decreased to 7.6 A due to release by the evacuation.

Cranial reshaping employing distraction and contraction in the treatment of sagittal synostosis

We treated four patients with scaphocephaly using a combination of distraction and contraction techniques and achieved satisfactory results. Radial osteotomies in the frontal and occipital bones flattened these abnormal bossing bones and accelerated the disappearance of bony bumps created by distraction. This technique facilitates the achievement of the desired shape of the skull through fine adjustments of the distraction and contraction devices.

Ulnar recurrent adipofascial flap for reconstruction of massive defects around the elbow and forearm

An ulnar recurrent adipofascial flap was raised and turned over to reconstruct massive defects around the elbow and forearm after wide resection of malignant tumours. Compared to the fasciocutaneous flap, the ulnar recurrent adipofascial flap has the following advantages: (1) a larger flap can be harvested without the problem of primary closure of the donor site, (2) the contour and scar of the donor site is reasonably acceptable since no tension is presented, (3) the flap can be turned over to cover a wider area, and (4) debulking of the flap can be performed during the operation if needed. The rotation arc of the ulnar recurrent adipofascial flap reaches a wide region, including the distal one-half of the upper arm, the elbow, and the proximal two-thirds of the forearm. Sensory deficit in the forearm was avoided in our patients because meticulous separation and preservation of the medial cutaneous nerve of the forearm was achieved without jeopardising the blood supply to the flap. The ulnar recurrent adipofascial flap is an easy and reliable option for one-stage reconstruction of massive defects around the elbow.