Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extracellular acidity is associated with tumor progression. Elevated glycolysis and acidosis promote the appearance of aggressive malignant cells with enhanced multidrug resistance. Thus, targeting of tumor acidity can open new avenues in diagnosis and treatment of aggressive tumors and targeting metastatic cancers cells within a tumor. pH (low) insertion peptides (pHLIPs) belong to the class of pH-sensitive agents capable of delivering imaging and/or therapeutic agents to cancer cells within tumors. Here, we investigated targeting of highly metastatic 4T1 mammary tumors and spontaneous breast tumors in FVB/N-Tg (MMTV-PyMT)634Mul transgenic mice with three fluorescently labeled pHLIP variants including well-characterized WT-pHLIP and, recently introduced, Var3- and Var7-pHLIPs. The Var3- and Var7-pHLIPs constructs have faster blood clearance than the parent WT-pHLIP. All pHLIPs demonstrated excellent targeting of the above breast tumor models with tumor accumulation increasing over 4 h postinjection. Staining of nonmalignant stromal tissues in transgenic mice was minimal. The pHLIPs distribution in tumors showed colocalization with 2-deoxyglucose and the hypoxia marker, Pimonidazole. The highest degree of colocalization of fluorescent pHLIPs was shown to be with lactate dehydrogenase A, which is related to lactate production and acidification of tumors. In sum, the pHLIP-based targeting of breast cancer presents an opportunity to monitor metabolic changes, and to selectively deliver imaging and therapeutic agents to tumors.
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PMID:Targeting breast tumors with pH (low) insertion peptides. 2500 2

Hypoxia, or low oxygen concentration, is a key factor promoting tumor progression and angiogenesis and resistance of cancer to radiotherapy and chemotherapy. 2-Nitroimidazole-based agents have been widely used in pathological and nuclear medicine examinations to detect hypoxic regions in tumors; in particular, pimonidazole is used for histochemical staining of hypoxic regions. It is considered to accumulate in hypoxic cells via covalent binding with macromolecules or by forming reductive metabolites after reduction of its nitro group. However, the detailed mechanism of its accumulation remains unknown. In this study, we investigated the accumulation mechanism of pimonidazole in hypoxic tumor tissues in a mouse model by mass spectrometric analyses including imaging mass spectrometry (IMS). Pimonidazole and its reductive metabolites were observed in the tumor tissues. However, their locations in the tumor sections were not similar to the positively stained areas in pimonidazole-immunohistochemistry, an area considered hypoxic. The glutathione conjugate of reduced pimonidazole, a low-molecular-weight metabolite of pimonidazole, was found in tumor tissues by LC-MS analysis, and our IMS study determined that the intratumor localization of the glutathione conjugate was consistent with the area positively immunostained for pimonidazole. We also found complementary localization of the glutathione conjugate and reduced glutathione (GSH), implying that formation of the glutathione conjugate occurred in the tumor tissue. These results suggest that in hypoxic tumor cells, pimonidazole is reduced at its nitro group, followed by conjugation with GSH.
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PMID:Imaging Mass Spectrometry Revealed the Accumulation Characteristics of the 2-Nitroimidazole-Based Agent "Pimonidazole" in Hypoxia. 2758 Feb 39