Mechanochemical Disruption Suppresses Metastatic Phenotype and Pushes Prostate Cancer Cells toward Apoptosis

Pre-Exposure to Stress-Inducing Agents Increase the Anticancer Efficacy of Focused Ultrasound against Aggressive Prostate Cancer Cells

Despite the initial success in treatment of localized prostate cancer (PCa) using surgery, radiation or hormonal therapy, recurrence of aggressive tumors dictates morbidity and mortality. Focused ultrasound (FUS) is being tested as a targeted, noninvasive approach to eliminate the localized PCa foci, and strategies to enhance the anticancer potential of FUS have a high translational value. Since aggressive cancer cells utilize oxidative stress (Ox-stress) and endoplasmic reticulum stress (ER-stress) pathways for their survival and recurrence, we hypothesized that pre-treatment with drugs that disrupt stress-signaling pathways in tumor cells may increase FUS efficacy. Using four different PCa cell lines, i.e., LNCaP, C4-2B, 22Rv1 and DU145, we tested the in vitro effects of FUS, alone and in combination with two clinically tested drugs that increase Ox-stress (i.e., CDDO-me) or ER-stress (i.e., nelfinavir). As compared to standalone FUS, significant (p < 0.05) suppressions in both survival and recurrence of PCa cells were observed following pre-sensitization with low-dose CDDO-me (100 nM) and/or nelfinavir (2 µM). In drug pre-sensitized cells, significant anticancer effects were evident at a FUS intensity of as low as 0.7 kW/cm². This combined mechanochemical disruption (MCD) approach decreased cell proliferation, migration and clonogenic ability and increased apoptosis/necrosis and reactive oxygen species (ROS) production. Furthermore, although activated in cells that survived standalone FUS, pre-sensitization with CDDO-me and/or nelfinavir suppressed both total and activated (phosphorylated) NF-κB and Akt protein levels. Thus, a combined MCD therapy may be a safe and effective approach towards the targeted elimination of aggressive PCa cells.

Targeting the extracellular matrix for immunomodulation: applications in drug delivery and cell therapies

Host immune cells interact bi-directionally with their extracellular matrix (ECM) to receive and deposit molecular signals, which orchestrate cellular activation, proliferation, differentiation, and function to maintain healthy tissue homeostasis. In response to pathogens or damage, immune cells infiltrate diseased sites and synthesize critical ECM molecules such as glycoproteins, proteoglycans, and glycosaminoglycans to promote healing. When the immune system misidentifies pathogens or fails to survey damaged cells effectively, maladies such as chronic inflammation, autoimmune diseases, and cancer can develop. In these conditions, it is essential to restore balance to the body through modulation of the immune system and the ECM. This review details the components of dysregulated ECM implicated in pathogenic environments and therapeutic approaches to restore tissue homeostasis. We evaluate emerging strategies to overcome inflamed, immune inhibitory, and otherwise diseased microenvironments, including mechanical stimulation, targeted proteases, adoptive cell therapy, mechanomedicine, and biomaterial-based cell therapeutics. We highlight various strategies that have produced efficacious responses in both pre-clinical and human trials and identify additional opportunities to develop next-generation interventions. Significantly, we identify a need for therapies to address dense or fibrotic tissue for the treatment of organ tissue damage and various cancer subtypes. Finally, we conclude that therapeutic techniques that disrupt, evade, or specifically target the pathogenic microenvironment have a high potential for improving therapeutic outcomes and should be considered a priority for immediate exploration. A schematic showing the various methods of extracellular matrix disruption/targeting in both fibrotic and cancerous environments. a Biomaterial-based cell therapy can be used to deliver anti-inflammatory cytokines, chemotherapeutics, or other factors for localized, slow release of therapeutics. b Mechanotherapeutics can be used to inhibit the deposition of molecules such as collagen that affect stiffness. c Ablation of the ECM and target tissue can be accomplished via mechanical degradation such as focused ultrasound. d Proteases can be used to improve the distribution of therapies such as oncolytic virus. e Localization of therapeutics such as checkpoint inhibitors can be improved with the targeting of specific ECM components, reducing off-target effects and toxicity.

Remote control of magnetic nanocomplexes for delivery and destruction of cancer cells

Although nanotechnology advances have been exploited for a myriad of purposes, including cancer diagnostics and treatment, still there is little discussion about the mechanisms of remote control. Our main aim here is to explain the possibility of a magnetic field control over magnetic nanocomplexes to improve their delivery, controlled release and antitumor activity. In doing so we considered the nonlinear dynamics of magnetomechanical and magnetochemical effects based on free radical mechanisms in cancer development for future pre-clinical studies.

Can ultrasound irradiation be a therapeutic option for prostate cancer?

BACKGROUND

Focal therapies for prostate cancer (PC) can reduce adverse events and do not lead to androgen-independent progression. Ultrasound could be used for cancer treatments if the repetition frequency is fitted to the purpose. We investigated the possible therapeutic effect of ultrasound irradiation on PC cells.

MATERIALS AND METHODS

We irradiated two PC cell lines, androgen-dependent LNCaP and -independent PC-3 with ultrasound (3.0 W/cm² , 3 MHz, irradiation time rate: 20%) for 2 minutes for 1 day or 3 consecutive days at a repetition frequency of 1, 10, or 100 Hz in vitro. Cell proliferation and apoptosis were determined after irradiation.

RESULTS

Cell proliferation of PC-3 was significantly inhibited after 1 day (P < .0001) and 3 days (P < .0001) of 10 Hz ultrasound irradiation, and that of LNCaP after 1 day (P < .0001) and 3 days (P < .0001) of irradiation. LNCaP was more sensitive to ultrasound at both lower and higher cell density but PC-3 was only sensitive at a lower cell density (P < .01). Irradiation with 10 Hz ultrasound-induced significantly more PC-3 apoptotic cells than control (1 day, P = .0137; 3 days, P = .0386) rather than irradiation with 1 Hz. Apoptosis via caspase-3 was induced at 10 Hz in 1-day (P < .05) irradiation in both cell lines.

CONCLUSIONS

Ultrasound irradiation with even 1 day of 10 Hz significantly inhibited cell proliferation in both LNCaP and PC-3, especially by the remarkable induction of apoptosis in vitro. Our study indicated that ultrasound irradiation can be a therapeutic option for PC and further studies in vivo will be undertaken.

Phenotypic alterations in liver cancer cells induced by mechanochemical disruption

Hepatocellular carcinoma (HCC) is a highly fatal disease recognized as a growing global health crisis worldwide. Currently, no curative treatment is available for early-to-intermediate stage HCC, characterized by large and/or multifocal tumors. If left untreated, HCC rapidly progresses to a lethal stage due to favorable conditions for metastatic spread. Mechanochemical disruption of cellular structures can potentially induce phenotypic alterations in surviving tumor cells that prevent HCC progression. In this paper, HCC response to mechanical vibration via high-intensity focused ultrasound and a chemical disruptive agent (ethanol) was examined in vitro and in vivo. Our analysis revealed that mechanochemical disruption caused a significant overproduction of reactive oxygen species (ROS) in multiple HCC cell lines (HepG2, PLC/PRF/5, and Hep3B). This led to a decrease in cell viability and long-term proliferation due to increased expression and activity of death receptors TNFR1 and Fas. The cells that survived mechanochemical disruption had a reduced expression of cancer stem cell markers (CD133, CD90, CD49f) and a diminished colony-forming ability. Mechanochemical disruption also impeded HCC migration and their adhesion to vascular endothelium, two critical processes in hematogenous metastasis. The HCC transformation to a non-tumorigenic phenotype post mechanochemical disruption was confirmed by a lack of tumor spheroid formation in vitro and complete tumor regression in vivo. These results show that mechanochemical disruption inhibits uncontrolled proliferation and reduces tumorigenicity and aggressiveness of HCC cells through ROS overproduction and associated activation of TNF- and Fas-mediated cell death signaling. Our study identifies a novel curative therapeutic approach that can prevent the development of aggressive HCC phenotypes.