Hormone-stimulated lipolysis is a rapid way to mobilize fat from its storage depot for use in peripheral tissues. By convention, activation of cytosolic lipases via the β-adrenergic receptor ...(ADRB2)-cAMP signaling pathway is the only molecular mechanism considered to liberate fatty acids from triglycerides stored in lipid droplets (LDs) of cells. Herein, we provide evidence that, aside from the activation of cytosolic lipases, autophagy contributes to this hormone-stimulated lipolysis. The ADRB2-stimulated lipolysis was reduced after inhibition of early or late autophagy using either pharmacological inhibitors or shRNA-mediated autophagic gene knockdown. ADRB2 stimulation has caused a marked increase in the autophagy-targeted LDs for lysosomal degradation, which is dependent on the LD-associated RAB7 as evidenced by the use of both shRNA-mediated RAB7 knockdown and a dominant-negative RAB7 mutant. In addition, RAB7 is involved in unstimulated (basal) lipolysis, and mediates the enhanced basal lipolysis in PLIN1/perilipin 1 knockdown fat cells. In conclusion, our results showed a contribution of lipophagy to both basal and hormone-stimulated lipolysis and that RAB7 plays a pivotal role in the regulation of this autolysosome-mediated lipid degradation in fat cells.
Poorly differentiated pancreatic neuroendocrine carcinomas (NECs) are rare and aggressive malignancies with rapid disease progression and early widespread metastasis. Given histology similarity, they ...are commonly treated with platinum-based chemotherapy as small cell lung cancer (SCLC). However, no standard treatment has been established for recurrent or progressive disease. We present an Asian patient with recurrent poorly differentiated pancreatic NEC after curative surgery and adjuvant chemotherapy with cisplatin and etoposide. The tumor mutational burden (TMB) was high. The patient received chemotherapy combined with maintenance immunotherapy with nivolumab and achieved promising and durable response, suggesting TMB could be a biomarker to identify NEC patients for immune checkpoint inhibitor (ICI) treatment.
Genetic alterations for epithelial ovarian cancer are insufficiently characterized. Previous studies are limited regarding included histologies, gene numbers, copy number variant (CNV) detection, and ...interpretation of pathway alteration patterns of individual patients.
We sequenced 410 genes to analyze mutations and CNV of 82 ovarian carcinomas, including high-grade serous (n = 37), endometrioid (n = 22) and clear cell (n = 23) histologies. Eligibility for targeted therapy was determined for each patient by a pathway-based approach. The analysis covered DNA repair, receptor tyrosine kinase, PI3K/AKT/MTOR, RAS/MAPK, cell cycle, and hedgehog pathways, and included 14 drug targets.
Postulated PARP, MTOR, and CDK4/6 inhibition sensitivity were most common. BRCA1/2 alterations, PTEN loss, and gain of PIK3CA and CCND1 were characteristic for high-grade serous carcinomas. Mutations of ARID1A, PIK3CA, and KRAS, and ERBB2 gain were enriched in the other histologies. PTEN mutations and high tumor mutational burden were characteristic for endometrioid carcinomas. Drug target downstream alterations impaired actionability in all histologies, and many alterations would not have been discovered by key gene mutational analysis. Individual patients often had more than one actionable drug target.
Genetic alterations in ovarian carcinomas are complex and differ among histologies. Our results aid the personalization of therapy and biomarker analysis for clinical studies, and indicate a high potential for combinations of targeted therapies.
Bevacizumab-based regimens are used as standard treatments for colorectal cancer. Unfortunately, there are no established predictive markers for bevacizumab response.
Tumor samples from 36 metastatic ...colorectal cancer patients treated with bevacizumab plus chemotherapy were analyzed by next-generation sequencing of all coding exons of more than 400 genes. Single gene and signaling pathway analyses were performed to correlate genomic data with response.
Among the genes most frequently mutated in our cohort, only mutations in
, a phosphatase involved in
signaling, were associated with response status, with deleterious mutations being enriched in non-responders. Pathway analysis revealed that deleterious mutations in genes of the
pathway, namely in
and the related gene
, correlated with resistance. Mutations in
,
and
pathways did not associate with response. Lack of response was observed in all patients with deleterious mutations or copy number loss of
/
(
= 10), compared to only 30.8% (
= 8) of patients without such alterations (relative risk, 3.25; 95% CI, 1.83⁻5.79,
= 0.0003). Similarly,
/
deleterious alterations were associated with shorter progression-free survival, an association that was retained in multivariate analysis (HR, 3.33; 95% CI, 1.47⁻7.54;
= 0.0038).
Deleterious alterations in
/
are potential biomarkers for bevacizumab resistance.
Genetic aberrations involving DNA damage repair (DDR) remain underexplored in gastrointestinal stromal tumors (GISTs). We characterized DDR abnormalities using targeted next-generation sequencing and ...multiplex ligation-dependent probe amplification, and performed immunofluorescence (IF) and immunohistochemistry (IHC) analyses of γH2AX and 53BP1. Consistent with IF-validated nuclear co-localization, γH2AX and 53BP1 showed robust correlations in expression levels, as did both biomarkers between IF and IHC. Without recurrent pathogenic single-nucleotide variants, heterozygous deletions (HetDels) frequently targeted DNA damage-sensing genes, with CHEK2-HetDel being the most prevalent. Despite their chromosomal proximity, BRCA2 and RB1 were occasionally hit by HetDels and were seldom co-deleted. HetDels of CHEK2 and BRCA2 showed a preference for older age groups, while RB1-HetDel predominated in the non-gastric, high-risk, and 53BP1-overexpressing GISTs. Higher risk levels were consistently related to γ-H2AX or 53BP1 overexpression (all p < 0.01) in two validation cohorts, while only 53BP1 overexpression was associated with the deletion of KIT exon 11 (KITex11-del) among genotyped GISTs. Low expressers of dual biomarkers were shown by univariate analysis to have longer disease-free survival (p = 0.031). However, higher risk levels, epithelioid histology, and KITex11-del retained prognostic independence. Conclusively, IHC is a useful surrogate of laborious IF in the combined assessment of 53BP1 and γ-H2AX to identify potential DDR-defective GISTs, which were frequently aberrated by HetDels and a harbinger of progression.
The diagnosis of anaplastic lymphoma kinase (ALK)-negative inflammatory myofibroblastic tumors (IMT) remains challenging because of their morphological resemblance with spindle cell sarcoma with ...myofibroblastic characteristics.
A 69-year-old female patient presented with loco-regional recurrent IMT several times within 8 years after primary treatment and neck lymph node metastasis 3.5 years after last recurrence.
The primary, recurrence, and lymph node metastasis lesions were diagnosed as ALK-negative IMTs based on the histopathological features.
Biopsy samples were obtained during repeated surgeries and evaluated for genomic alterations during first and recurrent presentations. The evaluation was done using pathway-driven massive parallel sequencing, and genomic alterations between primary and recurrent tumors were compared.
Copy number gains and overexpression of mouse double minute 2 homolog (MDM2) and cyclin dependent kinase 4 (CDK4) were observed in the primary lesion, and additional gene amplification of Discoidin Domain Receptor Tyrosine Kinase 2 (DDR2), Succinate Dehydrogenase Complex II subunit C (SDHC), and thyroid stimulating hormone receptor (TSHR) Q720H were found in the recurrent tumors. Metastases to the neck lymph node were observed 3.5 years after recurrence.
Our results indicated genetic evolution in a microscopically benign condition and highlighted the importance of molecular characterization of fibro-inflammatory lesions of uncertain malignant potential.
The molecular underpinnings of seromucinous borderline tumor (SMBT) – an uncommon ovarian epithelial neoplasm characterized by association with endometriosis, frequent bilateral ovarian involvement, ...and occasional progression to invasive carcinoma – remain poorly understood. Here, we sought to comprehensively characterize the mutational landscape of SMBT and elucidate the clonal relationship between bilateral ovarian SMBTs. We also compared the mutational profiles between SMBTs and concurrent invasive carcinomas. Formalin-fixed, paraffin-embedded tissue specimens were retrieved from 28 patients diagnosed with SMBT. Massively parallel sequencing of 409 cancer-related genes was conducted to identify somatic mutations in 33 SMBT samples and four concurrent invasive carcinoma specimens. TERT promoter mutations were assessed by Sanger sequencing, whereas immunohistochemistry was used as a surrogate tool for detecting deletions or epigenetic silencing of relevant tumor suppressor genes. Twenty-six (92.9%) of the 28 patients were diagnosed with stage I SMBTs. Seven (25%) cases showed bilateral ovarian involvement and 13 (46%) had concomitant endometriosis. Concurrent ovarian carcinomas were identified in three patients, whereas one case had a synchronous endometrial carcinoma. Somatic mutations in the KRAS, PIK3CA, and ARID1A genes were identified in 100, 60.7, and 14.3% of SMBT samples, respectively. In contrast, TERT promoter mutations and DNA mismatch repair deficiencies were absent. Sequencing of paired specimens from patients with bilateral SMBT revealed the presence of at least two shared somatic mutations, suggestive of a clonal relationship. Similarly, we identified shared somatic mutations between SMBT samples and concurrent ovarian carcinoma specimens. Taken together, these findings demonstrated a distinct mutational landscape of SMBT in which (1) KRAS is invariably mutated, (2) PIK3CA is frequently mutated, and (3) TERT promoter mutations and DNA mismatch repair deficiencies are absent. Our findings represent the first extensive characterization of this rare ovarian neoplasm, with potential implications for disease classification and molecular diagnostics.
Upon nutrient deprivation, cells are thought to suppress biosynthesis but activate catabolic pathways to provide alternative energy sources and nutrients. However, here we provide evidence that in ...adult male C. elegans, both biosynthesis and degradation activities, including ribosome biogenesis and turnover, are enhanced during early starvation and appear to depend on the availability of intestinal lipid stores. Upon depletion of the intestinal lipids, further food deprivation results in a significant reduction in metabolic activity in the starved male worms. Our data show that adult C. elegans exhibits a two-phase metabolic response to starvation stress: an initial phase with enhanced metabolic activity that rapidly exhausts the lipid stores, followed by a phase with low metabolic activity, which outlasts the life of fed control worms. DAF-2 insulin/IGF-1 receptor signaling to the RAS pathway is required for the starvation-induced ribosome biogenesis and rapid lipid depletion in the initial phase of starvation.
► Short-term starvation enhances both biosynthesis and degradation activities ► Intestinal lipid stores are rapidly depleted upon short-term starvation ► Starvation-enhanced ribosome biogenesis requires intestinal lipids ► Starvation-enhanced ribosome biogenesis depends on DAF-2 signaling to the RAS pathway
BACKGROUNDThe prognosis of triple-negative breast cancer (TNBC) is worse and a major proportion of TNBC expresses epidermal growth factor receptor (EGFR). Afatinib can inhibit EGFR signal pathway; ...however, its treatment effect for TNBC is unknown. Thus, we aimed to assess the efficacy and biomarkers of afatinib in combination with paclitaxel in a neoadjuvant setting. METHODSPatients with stage II to III TNBC were enrolled. They received 40 mg of afatinib daily for 14 days, followed by daily afatinib and weekly paclitaxel (80 mg/m2) every 21 days for four to six cycles. To explore the mechanisms of responsiveness and non-responsiveness, 409 cancer-associated genes were sequenced. RESULTSTwenty-one patients were enrolled and one patient achieved a complete clinical response; however, a 2 mm residual tumor was noted in the surgical specimen. Overall, 33.0% patients were responders. Fifteen patients received molecular testing. No activated mutation of EGFR or Her2 were found. Activated PI3K or JAK2 pathway were trended to associate with non-responder (p = 0.057). Mutation of homologous recombination (HR) genes were correlated with non-responsiveness (p = 0.005). Seven patients did not have altered PI3K, JAK2 or HR pathway; six (85.7%) of them were responder. Patients with the amplified DAXX gene was associated with a favorable trend of response (p = 0.109). CONCLUSIONAdding afatinib to neoadjuvant paclitaxel generated a modest effect in TNBC. Exploratory molecular analysis suggested that activated PI3K, JAK2 pathways and mutation of HR genes were associated with therapeutic non-responsiveness, and amplification of DAXX genes was associated with responsiveness to afatinib in combination with paclitaxel.
Combined hepatocellular cholangiocarcinoma (cHCC-CC) is a rare subtype of primary liver malignancy characterized by aggressive behavior and poor prognosis. Radial surgical resection is the standard ...curative treatment. However, effective therapeutic options for recurrent or metastatic cHCC-CC are still lacking, mainly because of an insufficient understanding of the molecular and genomic alterations of cHCC-CC, preventing the discovery of specialized targeting therapy. Here, we present the case of a patient with metastatic cHCC-CC on first-line treatment of gemcitabine, cisplatin, and nab-paclitaxel. A comprehensive genomic profile revealed four clinically relevant single nucleotide variants (BRCA2, PIK3C2G, RET, and TP53), two amplified genomic regions (CRKL and MAPK1), and 11 heterozygous genomic deletions (BAP1, CDKN2A, PTCH1, TSC1, BRCA2, RB1, RAD51, PALB2, TSC2, SMAD4, and STK11). The patient underwent olaparib treatment and achieved a remarkable and sustained tumor response. Our experience indicates that BRCA2 mutations could be a potential therapeutic target for patients with cHCC-CC. Keywords: combined hepatocellular cholangiocarcinoma, BRCA2 mutation, olaparib, comprehensive genomic panel, precision oncology
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