Search results for " Drug Resistance"

Antiproliferative Effects of St. John’s Wort, Its Derivatives, and Other Hypericum Species in Hematologic Malignancies

2021

Hypericumis a widely present plant, and extracts of its leaves, flowers, and aerial elements have been employed for many years as therapeutic cures for depression, skin wounds, and respiratory and inflammatory disorders. Hypericum also displays an ample variety of other biological actions, such as hypotensive, analgesic, anti-infective, anti-oxidant, and spasmolytic abilities. However, recent investigations highlighted that this species could be advantageous for the cure of other pathological situations, such as trigeminal neuralgia, as well as in the treatment of cancer. This review focuses on the in vitro and in vivo antitumor effects of St. John’s Wort (Hypericum perforatum), its derivat…

Cigarette smoking habit does not reduce the benefit from first line trastuzumab-based treatment in advanced breast cancer patients.

2011

Many ErbB2-positive cancers may show intrinsic resistance, and the frequent development of acquired resistance to ErbB-targeted agents represents a substantial clinical problem. The constitutive NF-κB activation in some HER-2/neu positive breast cancer may represent a potential cause of resistance to trastuzumab therapy. Preclinical data revealed that 4-(N-Methyl-N- nitrosamino)-1-(3-pyridyl)-1-butanone (NNK), the tobacco-specific nitrosamine is able to enhance NF-κB DNA binding activity and theoretically to increase the resistance to trastuzumab. Two hundred and forty-eight women with pathologically confirmed, uni- or bidimensionally measurable, HER-2-positive metastatic breast cancer (MBC…

Treatment for patients with relapsed/refractory mantle cell lymphoma: European-based recommendations

2017

International audience; Patients with mantle cell lymphoma (MCL) usually respond to initial combination chemotherapy, but the disease inevitably relapses and often follows an aggressive course. Here, clinical study results published since 2008 for patients with relapsed/refractory MCL were reviewed to compare available evidence for treatment guidance. Most trials identified were non-randomized, phase II studies performed at a limited number of sites, and many evaluated MCL as one of multiple non-Hodgkin lymphoma subtypes. Additional randomized, comparative trials are needed. Treatment selection generally depends on patient need, age and fitness, time of relapse, and line of therapy. Combina…

Cetuximab rechallenge in metastatic colorectal cancer patients: how to come away from acquired resistance?

2012

Background: Scientific data provide the evidence that secondary K-RAS mutations do not occur during anti-epidermal growth factor receptor therapy in colorectal cancer patients. This multicenter phase II prospective study aims to investigate the activity of a retreatment with a cetuximab-based therapy. Patients and methods: We enrolled 39 irinotecan-refractory patients who had a clinical benefit after a line of cetuximab- plus irinotecan-based therapy and then a progression of disease for which underwent a new line chemotherapy and finally, after a clear new progression of disease, were retreated with the same cetuximab- plus irinotecan-based therapy. Results: Median number of therapeutic li…

Salvage treatment for children with relapsed/refractory germ cell tumors: The Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) experienc…

2020

Background Malignant germ cell tumors (GCTs) are a heterogeneous group of rare neoplasms in children. Optimal outcome is achieved with multimodal therapies for patients with both localized and advanced disease, especially after the introduction of platinum-based chemotherapy regimens. In this respect, data on salvage treatment for children with relapsed or platinum-refractory disease are still limited. Methods Retrospective analysis of data regarding patients affected by malignant GCTs with platinum-refractory or relapsed disease after first-line treatment according to AIEOP TCGM 2004 protocol was conducted. Results Twenty-one patients, 15 females and 6 males, were considered for the analys…

Heterogeneity of KRAS, NRAS, BRAF and PIK3CA mutations in metastatic colorectal cancer and potential effects on therapy in the CAPRI GOIM trial

2015

Background: Evidence suggests that metastatic colorectal carcinoma (mCRC) has a high level of intratumor heterogeneity. We carried out a quantitative assessment of tumor heterogeneity for KRAS, NRAS, BRAF and PIK3CA mutations, in order to assess potential clinical implications. Patients and methods: Tumor samples (n = 182) from the CAPRI-GOIM trial of first-line cetuximab + FOLFIRI in KRAS exon-2 wild-type mCRC patients were assessed by next-generation sequencing that allows quantitative assessment of mutant genes. Mutant allelic frequency was normalized for the neoplastic cell content and, assuming that somatic mutations usually affect one allele, the Heterogeneity Score (HS) was calculate…

New findings on primary and acquired resistance to anti-EGFR therapy in metastatic colorectal cancer: Do all roads lead to RAS?

2015

Abstract: Anti-epidermal growth factor receptor therapy with the monoclonal antibodies cetuximab and panitumumab is the main targeted treatment to combine with standard chemotherapy for metastatic colorectal cancer. Many clinical studies have shown the benefit of the addition of these agents for patients without mutations in the EGFR pathway. Many biomarkers, including KRAS and NRAS mutations, BRAF mutations, PIK3CA mutations, PTEN loss, AREG and EREG expression, and HER-2 amplification have already been identified to select responders to anti-EGFR agents. Among these alterations KRAS and NRAS mutations are currently recognized as the best predictive factors for primary resistance. Liquid b…

Gastrointestinal stromal tumors (GISTs): Focus on histopathological diagnosis and biomolecular features

2007

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors of the gastrointestinal tract that are believed to originate from a neoplastic transformation of the intestinal pacemaker cells (interstitial cells of Cajal) normally found in the bowel wall or their precursors. Although the microscopic features have been known for a long time, the defining characteristic of GIST is the presence of the cell-surface antigen CD117 (KIT), which is demonstrated by immunohistochemistry. KIT, which is a growth factor transmembrane receptor, is the product of the proto-oncogene c-kit (chromosome 4). Surgical removal remains the only curative treatment for patients with GISTs. Tumor size, mitotic index,…

Development and Partial Characterization of a Human T-Lymphoblastic Leukemic (CCRF-CEM) Cell Line Resistant to Etoposide. Analysis of Possible Circum…

1996

We have selected an etoposide-resistant variant (CCRF-CEM/VP-16) of the human T-lymphoblastic CCRF-CEM leukemia for study. Resistance to the topoisomerase II (topo II) inhibitor was about 11-fold and stable. Other data revealed that the new cell line had acquired an atypical, non-P-glycoprotein overexpressing multidrug resistant (MDR) phenotype with cross-resistance to other topo II inhibitors (amsacrine, doxorubicin, and mitoxantrone) and to glucocorticoids, but not to novobiocin, ICRF-187, vincristine or cisplatin. In a first instance, we assumed that altered drug-topo II interactions, based on quantitative and/or qualitative modifications of the enzyme, are a cause of resistance in the c…

2015

Multidrug resistance is a prevailing phenomenon leading to chemotherapy treatment failure in cancer patients. In the current study two known cytotoxic pseudoguaianolide sesquiterpene lactones; neoambrosin (1) and damsin (2) that circumvent MDR were identified. The two cytotoxic compounds were isolated using column chromatography, characterized using 1D and 2D NMR, MS, and compared with literature values. The isolated compounds were investigated for their cytotoxic potential using resazurin assays and thereafter confirmed with immunoblotting and in silico studies. MDR cells overexpressing ABC transporters (P-glycoprotein, BCRP, ABCB5) did not confer cross-resistance toward (1) and (2), indic…