Response rates in metastatic neuroendocrine tumors receiving peptide receptor radionuclide therapy and implications for future treatment strategies

BackgroundPeptide receptor radionuclide therapy is a targeted therapy used to treat unresectable somatostatin receptor-positive neuroendocrine tumors. The objective of this study was to evaluate response rates among neuroendocrine tumors of different primaries and identify factors relevant to future treatment strategies.MethodsWe retrospectively reviewed patients who received peptide receptor radionuclide therapy for neuroendocrine tumors from 2018 to 2019 at our institution. Patients were assessed with computed tomography/magnetic resonance imaging and ⁶⁸Ga-DOTATATE-positron emission tomography before and after 2 or 4 cycles of peptide receptor radionuclide therapy. Tumor response was evaluated by RECIST 1.1. Statistics included multinomial logistic regression models and Fisher exact test.ResultsTwenty-seven patients underwent 92 cycles of peptide receptor radionuclide therapy: pancreas (n = 11), small bowel (n = 7), and other (n = 9) neuroendocrine tumors. Overall, 30% (8 of 27) had partial response, 59% (16 of 27) stable disease, and 11% (3 of 27) progressed. Pancreatic neuroendocrine tumors responded differently from small bowel neuroendocrine tumors regardless of cycle number (P = .01). The majority of pancreatic neuroendocrine tumors (6 of 11) had partial response to peptide receptor radionuclide therapy, while all small bowel neuroendocrine tumors had stable disease. Pancreatic neuroendocrine tumors stable after 2 cycles were more likely to respond to additional cycles versus other neuroendocrine tumors (probability: 60% vs 11%).ConclusionPatients with unresectable advanced or metastatic pancreatic neuroendocrine tumors may benefit from a full course of peptide receptor radionuclide therapy, whereas other neuroendocrine tumors appear less likely to respond. Large prospective studies are needed to confirm these findings.     

Genetic modifiers of EGFR dependence in non-small cell lung cancer

Lung adenocarcinomas harboring activating mutations in the epidermal growth factor receptor (EGFR) represent a common molecular subset of non-small cell lung cancer (NSCLC) cases. EGFR mutations predict sensitivity to EGFR tyrosine kinase inhibitors (TKIs) and thus represent a dependency in NSCLCs harboring these alterations, but the genetic basis of EGFR dependence is not fully understood. Here, we applied an unbiased, ORF-based screen to identify genetic modifiers of EGFR dependence in EGFR-mutant NSCLC cells. This approach identified 18 kinase and kinase-related genes whose overexpression can substitute for EGFR in EGFR-dependent PC9 cells, and these genes include seven of nine Src family kinase genes, FGFR1, FGFR2, ITK, NTRK1, NTRK2, MOS, MST1R, and RAF1. A subset of these genes can complement loss of EGFR activity across multiple EGFR-dependent models. Unbiased gene-expression profiling of cells overexpressing EGFR bypass genes, together with targeted validation studies, reveals EGFR-independent activation of the MEK-ERK and phosphoinositide 3-kinase (PI3K)-AKT pathways. Combined inhibition of PI3K-mTOR and MEK restores EGFR dependence in cells expressing each of the 18 EGFR bypass genes. Together, these data uncover a broad spectrum of kinases capable of overcoming dependence on EGFR and underscore their convergence on the PI3K-AKT and MEK-ERK signaling axes in sustaining EGFR-independent survival.The term “oncogene addiction” has been used to describe the phenomenon whereby tumor cells exhibit singular reliance on an oncogene or oncogenic pathway for their survival, despite the accumulation of multiple genetic lesions (1). In non-small cell lung cancer (NSCLC), this principle is perhaps best exemplified with the finding that epidermal growth factor receptor (EGFR) mutations predict response to EGFR tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib, and thus represent a dependency in the subset of tumors harboring these alterations (2–6). However, though EGFR-mutant NSCLCs typically respond dramatically to EGFR TKIs, clinical responses are not universal, even within this genetically defined cohort, with the rate of objective response estimated to be ∼71% (5, 6). Furthermore, the overwhelming majority of patients who initially respond to EGFR inhibitors ultimately develop resistance to therapy (7). A deeper understanding of the genetic underpinnings of EGFR addiction, and how EGFR-mutant cells can overcome reliance on EGFR, may improve clinical outcomes.Here, we have applied an unbiased screening approach to identify genetic modifiers of EGFR dependence in NSCLC. Mounting evidence supports the existence of several genetic modifiers of EGFR dependence in EGFR-mutant NSCLC, which can reduce the degree to which these tumors rely on EGFR and thereby contribute to EGFR TKI resistance (8). Examples include amplification of the MET receptor tyrosine kinase (RTK) (9), activation of the NF-κB pathway (8), amplification of the HER2 (ERBB2) RTK (10), amplification of the CRKL gene (11), and activation of the AXL kinase (12). Notably, MET bypass can be reciprocally achieved via EGFR activation in MET-dependent cells (13), and analogous examples of reciprocal kinase switching have been reported in other kinase-driven cancer models (14, 15). These and other findings suggest that compensatory kinase switching may be a more general way in which oncogene-dependent cancers overcome reliance on their primary driver kinase (14, 16), but the full-range of kinases capable of mediating EGFR bypass has not been systematically studied.Recent advances in large-scale functional genetic libraries have made it possible to query a wide range of genetic perturbations for their ability to modulate specific cellular phenotypes in mammalian systems (17, 18). Using the model of EGFR-mutant, erlotinib-sensitive NSCLC cells, we have performed a systematic ORF-based screen to identify kinase and kinase-related genes whose overexpression can complement loss of EGFR activity in an EGFR-dependent context. Our findings indicate broad potential for EGFR substitution in the setting of EGFR dependence, with compensatory mechanisms commonly conferring EGFR-independent activation of the PI3K-AKT and MEK-ERK signaling pathways. Importantly, this approach has recovered known mechanisms of erlotinib resistance as well as identified novel mediators of EGFR bypass in EGFR-mutant NSCLC. These data support the idea that the EGFR-dependent state can be redundantly driven by diverse genetic inputs that commonly converge on shared downstream signaling nodes.     

Enterococcus osteomyelitis secondary to pyelonephritis

We report a case of enterococcus lumbar osteomyelitis that developed after post-operative pyelonephritis. A 78-year-old G2P2 with Stage III uterovaginal prolapse and genuine stress urinary incontinence who underwent laparoscopic-assisted vaginal hysterectomy, high uterosacral ligament suspension, tension-free vaginal tape-obturator approach, and cystoscopy presented with post-operative back pain. Work-up of her back pain revealed enterococcus pyelonephritis. She continued to have back pain despite outpatient antibiotic treatment and further work-up revealed enterococcus lumbar osteomyelitis at the level of L1–L2. Enterococcus vertebral osteomyelitis is a rare infection that can occur by hematogenous spread from an infection of the urinary tract.     

Interaction of the novel antipsychotic aripiprazole with 5-HT1A and 5-HT2A receptors: functional receptor-binding and in vivo electrophysiological studies

Background Aripiprazole (7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl]butoxy}-3,4-dihydro-2(1H)-quinolinone) is a novel antipsychotic with a mechanism of action that differs from current typical and atypical antipsychotics. Aripiprazole interacts with a range of receptors, including serotonin [5-hydroxytryptamine (5-HT)] and dopamine receptors. Materials and methods This study examined aripiprazole’s interactions with 5-HT systems in vitro and in vivo to further clarify its pharmacologic properties. Results Aripiprazole produced increases in [³⁵S]GTPγS binding to rat hippocampal membranes. Its potency (pEC₅₀ = 7.2) was similar to that of ziprasidone (7.1) and greater than that of 5-HT (6.7) and buspirone (6.4), a 5-HT_1A-receptor partial agonist, whereas its intrinsic activity was similar to that of ziprasidone and buspirone. The stimulatory effect of aripiprazole was blocked by WAY-100635, a 5-HT_1A-receptor antagonist. In in vivo electrophysiology studies, aripiprazole produced a dose-related reduction in the firing rate of 5-HT-containing dorsal raphe neurons in rats, which was both prevented and reversed by WAY-100635 administration. Aripiprazole showed a high affinity for human 5-HT_1A receptors (K _i = 4.2 nM) using parietal cortex membrane preparations. In membranes from cells expressing human recombinant receptors, aripiprazole bound with high affinity to 5-HT_2A receptors (K _i = 3.4 nM), moderate affinity to 5-HT_2C (K _i = 15 nM) and 5-HT₇ (K _i = 39 nM) receptors, and low affinity to 5-HT₆ receptors (K _i = 214 nM) and 5-HT transporter (K _i = 98 nM). In addition, aripiprazole potently blocked 5-HT_2A-receptor-mediated increases in intracellular Ca²⁺ levels in a rat pituitary cell line (IC₅₀ = 11 nM). Discussion These results support a partial agonist activity for aripiprazole at 5-HT_1A receptors in vitro and in vivo, and suggest important interactions with other 5-HT-receptor subtypes. This receptor activity profile may contribute to the antipsychotic activity of aripiprazole in humans.     

Thapsigargin shifts the CA set point of parathyroid cells to lower extracellular [CA]

The hypothesis that cytosolic calcium concentration ([Ca²⁺ _cyt]) is the primary regulator of parathyroid hormone (PTH) secretion is supported by a number of studies that show an inverse relationship between them. One agent shown to inhibit PTH secretion is thapsigargin, a sesquiterpene lactone that raises [Ca²⁺ _cyt] by inhibiting the Ca-ATPase that pumps Ca²⁺ from the cytosol into the lumen of the endoplasmic reticulum. Thapsigargin may act on the parathyroid cell other than to inhibit the Ca-ATPase, however, in ways that might also affect PTH secretion. We have tested its effects on functional parameters, such as protein synthesis, the exocytic machinery, and the ability of parathyroid cells to respond to different concentrations of extracellular Ca²⁺ ([Ca²⁺ _ex]). In particular, we have determined whether the inhibition of PTH secretion by thapsigargin is independent of or is modulated by changes in [Ca²⁺ _ex]. The results revealed no effects of thapsigargin on protein synthesis or the exocytic mechanisms within 2 h of treatment, and showed that [Ca²⁺ _ex] can modulate PTH secretion in the presence of thapsigargin. Its inhibition of PTH secretion, therefore, appears to rest on its ability to shift [Ca²⁺ _cyt] to higher levels, but the possibility that it interacts with the Ca receptor has not been eliminated. The results support the hypothesis that the primary regulator of steady-state PTH secretion is [Ca²⁺ _cyt].     

Nonpharmacologic approaches for the treatment of hyperlipidemia

Coronary heart disease (CHD) is the leading cause of death in the United States. Dyslipidemias, like decreased high-density lipoprotein (HDL) and increased low-density lipoprotein (LDL), have been linked through epidemiologic and experimental studies with the development of atherosclerosis and an increased risk of CHD. The introduction of various classes of lipid-lowering drugs, especially the hydroxymethylglutaryl-coenzyme-A-reductase inhibitors (statins), has allowed for effective treatment of hyperlipidemia. This article reviews the following nonpharmacologic approaches to hyperlipidemia: LDL apheresis, surgery, the emergence of HDL as a therapeutic target, gene therapy, and finally, the possibility of developing a vaccine against atherosclerosis.     

An efficient procedure for purification of recombinant human β heat shock protein 90

Background and the purpose of the study

Heat Shock Protein 90 (Hsp90) is typically the most abundant chaperone in the eukaryotic cell cytoplasm, and its expression is essential for loading immunogenic peptides onto major histocompatibility complex molecules for presentation to T-cells. Therefore, it may act as a good candidate as an adjuvant molecule in vaccine technology.

Methods

Initially the human Hsp90β gene was cloned into the heat inducible expression vector pGP1-2 and then the recombinant protein was isolated by ion exchange chromatography. After intradermal injection of confirmed purified band of protein to rabbits and isolation of the serum IgG antibody, for its affinity purification, the rabbit''s purified Hsp90 specific IgG was coupled to the cyanogen bromide-activated Sepharose 4B.

Results

The recovery of the purified protein of interest by affinity chromatography was 50%.

Conclusion

This research enabled purification of human heat shock protein by a laboratory prepared column chromatography.