Exosomes from Von Hippel-Lindau-Null Cancer Cells Promote Metastasis in Renal Cell Carcinoma.

Exosomes are extracellular vesicles that modulate essential physiological and pathological signals. Communication between cancer cells that express the von Hippel-Lindau (VHL) tumor suppressor gene and those that do not is instrumental to distant metastasis in renal cell carcinoma (RCC). In a novel metastasis model, VHL(-) cancer cells are the metastatic driver, while VHL(+) cells receive metastatic signals from VHL(-) cells and undergo aggressive transformation. This study investigates whether exosomes could be mediating metastatic crosstalk. Exosomes isolated from paired VHL(+) and VHL(-) cancer cell lines were assessed for physical, biochemical, and biological characteristics. Compared to the VHL(+) cells, VHL(-) cells produce significantly more exosomes that augment epithelial-to-mesenchymal transition (EMT) and migration of VHL(+) cells. Using a Cre-loxP exosome reporter system, the fluorescent color conversion and migration were correlated with dose-dependent delivery of VHL(-) exosomes. VHL(-) exosomes even induced a complete cascade of distant metastasis when added to VHL(+) tumor xenografts in a duck chorioallantoic membrane (dCAM) model, while VHL(+) exosomes did not. Therefore, this study supports that exosomes from VHL(-) cells could mediate critical cell-to-cell crosstalk to promote metastasis in RCC.

Response of Leptomeningeal Metastasis of Breast Cancer With a HER2/neu Activating Variant to Tucatinib: A Case Report.

Metastatic breast cancer demonstrates HER2/neu amplification approximately 15% of the time. However, HER2 mutations, which often stimulate tumor growth, occur in only 3% to 5% of patients, and are seen more frequently in metastatic versus primary tumors. They are more frequent in lobular carcinoma, including triple-negative lobular cancer. Many of these variants are resistant to trastuzumab and lapatinib. However, neratinib can be efficacious, and recent data suggest that antibody-drug conjugates (ADCs) such as ado-trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan may also be helpful. Laboratory and clinical data raise the possibility that simultaneous treatment with ADCs plus neratinib may be even more efficacious. Tucatinib, which has demonstrated significant activity in the central nervous system, has also been shown in vitro to be active against a number of these HER2 variants. This report describes a patient with metastatic estrogen receptor-positive, HER2-nonamplified breast cancer with an activating HER2 mutation whose tumor became resistant to neratinib as well as capecitabine, but whose subsequent leptomeningeal disease had a dramatically successful response to tucatinib plus capecitabine. As the frequency of HER2 mutations increases during the evolution of metastatic breast cancer, it is important to obtain genomic evaluation on these tumors with either repeat tissue or liquid biopsy as they progress over time.

Alterations of housekeeping proteins in human aged and diseased hearts.

Pathological remodeling includes alterations of ion channel function and calcium homeostasis and ultimately cardiac maladaptive function during the process of disease development. Biochemical assays are important approaches for assessing protein abundance and post-translational modification of ion channels. Several housekeeping proteins are commonly used as internal controls to minimize loading variabilities in immunoblotting protein assays. Yet, emerging evidence suggests that some housekeeping proteins may be abnormally altered under certain pathological conditions. However, alterations of housekeeping proteins in aged and diseased human hearts remain unclear. In the current study, immunoblotting was applied to measure three commonly used housekeeping proteins (ß-actin, calsequestrin, and GAPDH) in well-procured human right atria (RA) and left ventricles (LV) from diabetic, heart failure, and aged human organ donors. Linear regression analysis suggested that the amounts of linearly loaded total proteins and quantified intensity of total proteins from either Ponceau S (PS) blot-stained or Coomassie Blue (CB) gel-stained images were highly correlated. Thus, all immunoblotting data were normalized with quantitative CB or PS data to calibrate potential loading variabilities. In the human heart, ß-actin was reduced in diabetic RA and LV, while GAPDH was altered in aged and diabetic RA but not LV. Calsequestrin, an important Ca2+ regulatory protein, was significantly changed in aged, diabetic, and ischemic failing hearts. Intriguingly, expression levels of all three proteins were unchanged in non-ischemic failing human LV. Overall, alterations of human housekeeping proteins are heart chamber specific and disease context dependent. The choice of immunoblotting loading controls should be carefully evaluated. Usage of CB or PS total protein analysis could be a viable alternative approach for some complicated pathological specimens.

Impact of rocuronium vs succinylcholine neuromuscular blocking drug choice for laparoscopic pyloromyotomy: is there a difference in time to transport to recovery?

OBJECTIVES/AIM: This study evaluates the relationship between neuromuscular blocking drug administered and transport time following laparoscopic pyloromyotomy. BACKGROUND: Infants with pyloric stenosis have indication for rapid sequence induction. While succinylcholine has rapid onset and short duration, its use in children may be associated with rare serious adverse effects. Rocuronium is a widely accepted alternative, but its duration could contribute to delay at surgery end. METHODS: Infants undergoing laparoscopic pyloromyotomy at Loma Linda University Medical Center Children's Hospital from January 2006 to July 2011 were studied retrospectively. Only term infants receiving propofol induction, sevoflurane maintenance, no intraoperative opioid, and rocuronium, succinylcholine, or both were included. The primary outcome measure was time to transport after surgery stop as a measure of recovery from both anesthesia and relaxant. Data was analyzed for relationships between drug choice and time to transport. RESULTS: Data from 246 patients was analyzed. Patients were similar in all groups. Time to transport was not affected by doses of propofol or neuromuscular blocking drug, anesthesia to surgery end interval or surgery length. Time to transport (minutes median, interquartile range) was 13 (7-21) in patients receiving only succinylcholine compared to 18 (11-24) in those receiving only rocuronium (P=0.03). CONCLUSIONS: For laparoscopic pyloromyotomy in term infants using propofol, sevoflurane and no intraoperative opioid, succinylcholine may be the best neuromuscular blocking drug choice, provided no contraindication is present. However, based on the small difference in time to transport, rocuronium as administered herein may be a reasonable alternative preferred by some clinicians.