Special Issue: New Approaches to Counteract Drug Resistance in Cancer

Breaking the Silence of Tumor Response: Future Prospects of Targeted Radionuclide Therapy

Therapy-induced tumor resistance has always been a paramount hurdle in the clinical triumph of cancer therapy. Resistance acquired by tumor through interventions of chemotherapeutic drugs, ionizing radiation, and immunotherapy in the patientsis a severe drawback and major cause of recurrence of tumor and failure of therapeutic responses. To counter acquired resistance in tumor cells, several strategies are practiced such as chemotherapy regimens, immunotherapy, and immunoconjugates, but the outcome is very disappointing for the patients as well as clinicians. Radionuclide therapy using alpha or beta-emitting radionuclide as payload became state-of-the-art for cancer therapy. With the improvement in dosimetric studies, development of high-affinity target molecules, and design of several novel chelating agents which provide thermodynamically stable complexes in vivo, the scope of radionuclide therapy has increased by leaps and bounds. Additionally, radionuclide therapy along with the combination of chemotherapy is gaining importance in pre-clinics, which is quite encouraging. Thus, it opens an avenue for newer cancer therapy modalities where chemotherapy, radiation therapy, and immunotherapy are unable to break the silence of tumor response. This article describes, in brief, the causes of tumor resistance and discusses the potential of radionuclide therapy to enhance tumor response.

miRNAs mediated drug resistance in hematological malignancies

Despite improvements in the therapeutic approaches for hematological malignancies in the last decades, refractory disease still occurs, and cancer drug resistance still remains a major hurdle in the clinical management of these cancer patients. The investigation of this problem has been extensive and different mechanism and molecules have been associated with drug resistance. MicroRNAs (miRNAs) have been described as having an important action in the emergence of cancer, including hematological tumors, and as being major players in their progression, aggressiveness and response to treatments. Moreover, miRNAs have been strongly associated with cancer drug resistance and with the modulation of the sensitivity of cancer cells to a wide array of anticancer drugs. Furthermore, this role has also been reported for miRNAs packaged into extracellular vesicles (EVs-miRNAs), which in turn have been described as essential for the horizontal transfer of drug resistance to sensitive cells. Several studies have been suggesting the use of miRNAs as biomarkers for drug response and clinical outcome prediction, as well as promising therapeutic tools in hematological diseases. Indeed, the combination of miRNA-based therapeutic tools with conventional drugs contributes to overcome drug resistance. This review addresses the role of miRNAs in the pathogenesis of hematological malignances, namely multiple myeloma, leukemias and lymphomas, highlighting their important action (either in their cell-free circulating form or within circulating EVs) in drug resistance and their potential clinical applications.