1.1.2. Exosomal lncRNAs (Long Non-coding RNAs)
The transfer of exosomal lncRNAs between the tumor microenvironment and tumor cells is involved in events such as reprogramming the tumor microenvironment, growth, migration, and survival of cancer cells, as well as the development of mechanisms that cause resistance to chemotherapy [88]. In addition, because exosomal lncRNAs play a role in malignancy and response to treatment, they could be employed as biomarkers for many cancers [88]. There is evidence that lncRNAs promote drug resistance in diverse cancers [88]. For instance, lncRNA SBF2 (SET binding factor 2) induces temozolomide resistance in glioblastoma cells during chemotherapy [89]. During tumor growth, access to oxygen is limited due to poor vasculature within the developing solid tumor mass, which is called hypoxia [88]. Under hypoxia conditions, the hypoxia-inducible factor (HIF)-1α pathway is activated in tumor cells, which during oxygen stress, plays a role as an adaptive mechanism [90]. Moreover, the hypoxia condition promotes cell survival through the transcription of several lncRNAs [91, 92].