Description: <b>Sonodynamic therapy (SDT)</b> is an emerging, non-invasive treatment modality that employs ultrasound energy in conjunction with sonosensitizers to induce cytotoxicity in target tissues. A key mechanism by which SDT exerts its therapeutic effects is through the generation of reactive oxygen species (ROS). <br>
Also known as high-intensity focused ultrasound (HIFU)<br>
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SDT relies on the ultrasound-triggered activation of sonosensitizers (similar in concept to photosensitizers used in photodynamic therapy). When activated by ultrasound, these compounds undergo energy transitions that lead to the production of ROS, such as singlet oxygen and free radicals.<br>
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-Advantages of SDT include its non-invasive nature, deep tissue penetration of ultrasound, and the ability to target localized areas with high precision.<br>
-Challenges remain in precisely controlling ROS production and ensuring that the resulting oxidative stress is sufficient to induce cell death in tumor cells without overwhelming damage to surrounding normal tissues.<br>
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Sonosensitizers:<br>
– Hematoporphyrin Derivative (HPD) and Photofrin<br>
– Protoporphyrin IX (PpIX)<br>
– Chlorin e6 (Ce6)<br>
– Phthalocyanine compounds<br>
– Titanium Dioxide (TiO2) Nanoparticles<br>
– Other metallic or semiconductor nanoparticles, sometimes functionalized or loaded with traditional sensitizer molecules (e.g., gold nanoparticles, copper-cysteamine), have been explored to enhance ROS production and improve tumor targeting.<br>
– Curcumin, derived from turmeric, has been shown in several studies to exhibit sonosensitizing properties.<br>
– Under ultrasound activation, quercetin may act as a sonosensitizer, increasing ROS generation and contributing to cancer cell apoptosis.<br>
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US frequency range of 150 kHz–3 MHz, irradiation dose of 2–3 W cm−2, and the actuation duration range of 1–20 min are used for SDT research<br>
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<a href="https://can-amhifu.com/" > https://can-amhifu.com/ </a> <br>
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https://canadaclinicsupply.com/product/soundcare-plus-professional-dual-ultrasound-device-by-roscoe/
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https://physiostore.ca/product-category/therapeutic-modalities/therapeutic-ultrasound/clinical-ultrasound-systems/
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https://physiostore.ca/richmar-home-ultrasound-2000-2nd-edition/<br>
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-SDT is a pro-oxidant modality → strong antioxidants could theoretically reduce efficacy if present at high tissue levels (same logic as PDT), but this is highly protocol- and sensitizer-dependent.<br>
-Hypoxia can blunt ROS-based killing; strategies sometimes include oxygenation, microbubbles, or vascular modulation.<br>
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<!-- Sonodynamic Therapy (SDT) — Cancer-Oriented Time-Scale Flagged Pathway Table -->
<table border="1" cellpadding="4" cellspacing="0">
<tr>
<th>Rank</th>
<th>Pathway / Axis</th>
<th>Cancer / Tumor Context</th>
<th>Normal Tissue Context</th>
<th>TSF</th>
<th>Primary Effect</th>
<th>Notes / Interpretation</th>
</tr>
<tr>
<td>1</td>
<td>ROS burst (sonosensitizer activation)</td>
<td>ROS ↑↑ (local); oxidative damage ↑</td>
<td>Collateral ROS possible depending on targeting</td>
<td>P</td>
<td>Primary cytotoxic driver</td>
<td>Core SDT mechanism: ultrasound-activated sensitizers generate ROS; effectiveness depends on oxygenation and sensitizer localization.</td>
</tr>
<tr>
<td>2</td>
<td>Mitochondrial dysfunction (ΔΨm loss) → intrinsic apoptosis</td>
<td>ΔΨm ↓; cyt-c ↑; caspase-9/3 ↑ (reported)</td>
<td>↔ / injury possible at high exposures</td>
<td>R, G</td>
<td>Apoptosis execution</td>
<td>Often downstream of ROS; magnitude depends on dose and cell redox fragility.</td>
</tr>
<tr>
<td>3</td>
<td>Lipid peroxidation / membrane damage</td>
<td>Membrane integrity ↓; lipid peroxidation ↑</td>
<td>Off-target membrane injury possible</td>
<td>P, R</td>
<td>Cell damage / necrotic pressure</td>
<td>ROS and mechanical effects can destabilize membranes; can contribute to necrosis-like death if severe.</td>
</tr>
<tr>
<td>4</td>
<td>ER stress / UPR activation</td>
<td>ER stress ↑; CHOP ↑; UPR ↑ (reported)</td>
<td>↔ / stress response possible</td>
<td>R, G</td>
<td>Stress overload</td>
<td>ROS-triggered protein misfolding and calcium dysregulation can drive UPR and pro-death signaling.</td>
</tr>
<tr>
<td>5</td>
<td>DNA damage response (DDR)</td>
<td>DNA oxidation / breaks ↑; γH2AX ↑ (reported)</td>
<td>↔ / injury possible</td>
<td>R, G</td>
<td>Replication stress / apoptosis support</td>
<td>DNA damage is typically secondary to ROS; relevance depends on tumor proliferation state.</td>
</tr>
<tr>
<td>6</td>
<td>Ferroptosis-like signaling (context-dependent)</td>
<td>Lipid ROS ↑; GPX4 pressure ↑ (reported in some SDT papers)</td>
<td>↔</td>
<td>R, G</td>
<td>Non-apoptotic oxidative death</td>
<td>Some SDT systems push lipid peroxidation strongly enough to resemble ferroptosis; not universal.</td>
</tr>
<tr>
<td>7</td>
<td>Autophagy response</td>
<td>Autophagy ↑ (adaptive) or contributes to death (context)</td>
<td>↔</td>
<td>G</td>
<td>Stress adaptation</td>
<td>Autophagy can be protective or pro-death depending on magnitude of SDT stress and sensitizer localization.</td>
</tr>
<tr>
<td>8</td>
<td>Microenvironment effects (vascular permeability / perfusion)</td>
<td>Local perfusion changes; permeability ↑ (reported)</td>
<td>Potential local vascular injury</td>
<td>P, R</td>
<td>Delivery modulation</td>
<td>Ultrasound can increase permeability (esp. with microbubbles); may enhance drug delivery in some protocols.</td>
</tr>
<tr>
<td>9</td>
<td>Immune activation (DAMPs / ICD-like signals)</td>
<td>Immunogenic cell death signals ↑ (reported)</td>
<td>—</td>
<td>G</td>
<td>Anti-tumor immunity support</td>
<td>Cell stress/death can release DAMPs and promote antigen presentation; data vary by model and sensitizer.</td>
</tr>
<tr>
<td>10</td>
<td>Parameter dependence / safety constraints</td>
<td>Effect varies with sensitizer + ultrasound settings + oxygenation</td>
<td>Heating / cavitation injury risk if misapplied</td>
<td>—</td>
<td>Translation constraint</td>
<td>SDT outcomes depend heavily on ultrasound frequency/intensity/duty cycle and sensitizer biodistribution; not “plug-and-play.”</td>
</tr>
</table>
<p><b>Time-Scale Flag (TSF):</b> P / R / G</p>
<ul>
<li><b>P</b>: 0–30 min (ROS burst; immediate membrane/vascular effects)</li>
<li><b>R</b>: 30 min–3 hr (stress pathways: ER/DDR; apoptosis initiation)</li>
<li><b>G</b>: >3 hr (cell death execution; immune/phenotype outcomes)</li>
</ul>
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Sonodynamic Therapy — Common Sonosensitizer Classes
<!-- Sonodynamic Therapy (SDT) — Common Sonosensitizer Classes -->
<table border="1" cellpadding="4" cellspacing="0">
<tr>
<th>Sensitizer Class</th>
<th>Examples</th>
<th>Primary Mechanistic Bias</th>
<th>Dominant Death Pathways (Reported)</th>
<th>Notes / Interpretation</th>
</tr>
<tr>
<td><b>Porphyrins / Hematoporphyrin derivatives</b></td>
<td>Hematoporphyrin, Protoporphyrin IX, Photofrin-like agents</td>
<td>ROS generation (Type I/II-like chemistry under ultrasound)</td>
<td>Intrinsic apoptosis (ΔΨm ↓, cyt-c ↑), caspases ↑</td>
<td>Most classical SDT sensitizers; strong mitochondrial localization; mechanistically closest to PDT analogs.</td>
</tr>
<tr>
<td><b>Chlorins / Phthalocyanines</b></td>
<td>Chlorin e6 (Ce6), phthalocyanine derivatives</td>
<td>High ROS yield</td>
<td>Apoptosis ↑; lipid peroxidation ↑; ER stress ↑</td>
<td>Often used in nanoformulations to improve tumor accumulation and ultrasound activation efficiency.</td>
</tr>
<tr>
<td><b>Xanthene dyes</b></td>
<td>Eosin Y, Rose Bengal</td>
<td>ROS burst + membrane effects</td>
<td>Apoptosis ↑; necrotic pressure (dose-dependent)</td>
<td>Some studies show strong oxidative burst; selectivity depends on uptake and targeting.</td>
</tr>
<tr>
<td><b>Repurposed chemotherapeutics</b></td>
<td>Doxorubicin, 5-ALA (via PpIX accumulation)</td>
<td>Combined ROS + intrinsic drug mechanism</td>
<td>Apoptosis ↑; DDR ↑</td>
<td>Dual-mechanism systems: drug effect plus ultrasound-enhanced ROS; schedule-dependent outcomes.</td>
</tr>
<tr>
<td><b>Metal-based nanoparticles</b></td>
<td>TiO2, ZnO, MnO2-based systems</td>
<td>ROS catalysis; Fenton-like chemistry</td>
<td>Lipid peroxidation ↑; ferroptosis-like signaling (reported)</td>
<td>Often engineered to amplify ROS via catalytic surfaces; ferroptosis signatures reported in some platforms.</td>
</tr>
<tr>
<td><b>Organic nano-sonosensitizers</b></td>
<td>Polymeric micelles, liposome-loaded sensitizers</td>
<td>Targeted ROS release</td>
<td>Apoptosis ↑; immune activation (DAMPs ↑)</td>
<td>Improved tumor delivery; often combined with immune checkpoint therapy in preclinical systems.</td>
</tr>
<tr>
<td><b>Gas-generating / microbubble-assisted systems</b></td>
<td>O2-loaded microbubbles, perfluorocarbon systems</td>
<td>Cavitation + oxygenation enhancement</td>
<td>Enhanced ROS; vascular disruption</td>
<td>Used to overcome hypoxia and improve ROS yield; parameter-sensitive.</td>
</tr>
<tr>
<td><b>Natural compound–based sensitizers (experimental)</b></td>
<td>Curcumin, certain flavins (reported)</td>
<td>ROS generation (lower potency vs porphyrins)</td>
<td>Apoptosis ↑ (reported)</td>
<td>Less standardized; ROS yield and ultrasound responsiveness vary widely.</td>
</tr>
</table>